UNGIN. LID.
AUDELS
POWER PLANT
ENGINEERS GUIDE
WITH QUESTIONS AND ANSWERS
674
275
TJ
GPS
A 566612

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1

PRE-VIEW
SPECIAL FEATURES
Boilers, all types; boiler and engine room physics;
fireman's guide; boiler examination questions; boiler
operation; pulverized coal systems; instant steam;
boiler fixtures; boiler repairs and calculations. Boiler
accessories: feed pumps, feed water heaters, econo-
mizers; feed water treatment and deaeration; injectors;
safety valve calculations; mechanical stokers; oil burners;
condensers; air pumps and air ejectors; evaporators;
steam and hot water heating; pipe fitting. Steam
engines; valve gears; turbines; compressors; gas
and Diesel engines. Lubricants and lubrication.
A complete Power Plant Library. 1,500 pages.
Elaborate ready reference index. The A to Z of practi-
cal Steam Engineering.
HUNDREDS OF:
Skeleton diagrams showing basic construction.
Photographs showing actual construction.
Operating illustrations showing actual management.
Repair illustrations showing proper servicing.
Sketches illustrating the nature of steam.
FOR WHOM?
For all engineers, firemen, water tenders, oilers,
operators, repair men and applicants preparing for an
Engineer's License examination, or desiring to increase
their knowledge in quest of higher positions.
MAIN SUPERHEATED STEAM
VALVE
OUTLET TO ENGINE
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TWENS'HAVI{ENTR
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SUPER HEATER
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DRY PIPE
FEED DISTRIBUTER
SATURATED STEAM OUTLET
FOR AUXILIARIES
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ASH PAN
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STEAM AND
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Elements of-A STEAM BOILER
I





AUDELS
POWER
PLANT
ENGINEERS
GUIDE
גז
A PRACTICAL TREATISE
WITH }
EXAMINATION QUESTIONS AND ANSWERS
FOR
ENGINEERS · MECHANICS & OPERATORS
COVERING
THEORY, CONSTRUCTION AND OPERATION
OF POWER HOUSE MACHINERY
INCLUDING
STEAM BOILERS, ENGINES, TURBINES,
AUXILIARY EQUIPMENT ETC.
FULLY ILLUSTRATED
BY
FRANK D. GRAHAM
HARTERED
THEO. AUDEL & CO.,
49 WEST 23rd STREET
1
PUBLISHERS
NEW YORK IO N.Y.
..
COPYRIGHT
1945
THEO. AUDEL & CO.
NEW YORK
All Rights Reserved
Printed in the United States of America
Pho
AUTHOR'S NOTE
Euge
With
17
54.6
In writing a Preface, Foreword, Author's Note, or whatever
it be called, the author's opinion is the shorter the better.
Accordingly, there will be no wordage waste here.
The readers attention is called to just two items:
1. The purpose of this book is to include in one volume a
complete library of practical and theoretical Steam Engineering.
The numerous subjects are presented with forceful directness
in plain language and simple terms that anyone can understand.
The information it contains is all that is needed by the operating
engineers, firemen and boiler attendants; also by students pre-
paring to take examinations for all grades of Engineers'
Licenses.
The author introduces a large number of elementary skeleton dia-
grams to explain basic principles, construction being shown by photo-
graphs of the latest designs as brought out by the leading manufacturers.
2. An expression of thanks and appreciation is here given:
To the various manufacturers for their co-operation in fur-
nishing complete information covering their equipment.
To Evelyn K. Lawson for very efficient secretarial work, in-
cluding typing author's manuscript, proof reading, checking
and able assistance in making the index. To Geo. W. Hood for
masterly execution of line drawings from hundreds of the
author's pencil sketches. To Henry E. Raabe, M. E., for a
critical comparative analysis of Diesel engine performance
referred to the Otto Cycle and remarks on "The Fallacy of
Compounding." To Henry Harman, William Proner, Thomas
Lawn, Howard Gunn and William Williams for monotype
composition. To Patrick K. Quill and Edward B. Guinas for
make-up. Composition and make-up under the personal direction
of Charles J. La Motta.
and
To the Publishers for encouragement and suggestions during
the preparation of the book.
FRANK D. GRAHAM.
i
LIST OF CHAPTERS
Chapter 1 Basic Principles
2 Air..
3 Water.
4 Steam
5 Heat...
6 Fuels....
7 Combustion..
8 How A Boiler Makes Steam.
9 Boiler Types.
9A Instant Steam.
10 The Nature of Boilers.
11
12
13
•
•
19 Boiler Accessories..
20 Boiler Operation..
21 Boiler Repairs..
22 Boiler Calculations.
23 Boiler Feed Pumps.
24 Feed Water Heaters.
25 Economizers..
26 Feed Water Deaeration
Boiler Materials.
Properties of Boiler Materials.
Tests of Boiler Materials.
14 Shell Boiler Construction.
15 Shell Boiler Openings..
16 Water Tube Boiler Construction.
17 Strength of Boilers.
18 Boiler Fixtures and Attachments
•
31 Safety Valves .
32 Draught..
•
27 Feed Water Treatment
28 Feed Water Regulators
29 Injectors..
30 Steam Traps .
•
•
▸
•
•
Pages
1- 10
11- 16
17- 30
31- 58
59- 72
73- 80
81- 96
97- 108
109- 126
126A-126H
127-138
• ·
•
狰
​•
139- 140
141- 144
145- 154
155- 178
179- 184
185- 210
211- 244
245-276
277- 290
291- 344
345-354
355-370
371- 432
433-450
451- 458
459- 466
467-478
479-488
489-508
509-524
525-546
547-556
LIST OF CHAPTERS
Chapter 33 Mechanical Stokers...
34 Pulverized Coal Systems.
35 Oil Burners..
36
37
38 Steam Jet Air Ejectors.
39 Cooling Ponds and Cooling Towers..
40 Evaporators..
Condensers.
Condenser Calculations.
41 Big Boilers...
42 House Heating Boilers.
43 Steam Heating Systems.
44 Hot Water Heating.
·
• •
·
•
45 Heating Calculations
46 Pipe, Fittings, and Pipe Fitting.
47 Non-Ferrous Tubing and Fittings,
48 Steam Engines.
49
Indicators.
50 The Slide Valve.
51 The Valve Gears.
52 Variable Cut Off………
53 Reversing Valve Gears.
54 Valve Setting..
Hoists...
55
56
Steam Turbines.
57 Air Compressors
58 Inter and After Coolers..
•
•
•
•
59 Compressor Control Devices.
60 Compressor Operation.
61 Gas Engine Principles.
62 Diesel Engines.
63 Diesel Engine Performance.
64 Lubricants.
65 Lubrication.
Pages 557-586
587-612
613- 670
671- 712
713- 730
731-746
747-764
765-776
777-798
•
•
•
799- 814
815- 846
847-858
859- 882
883-926
927-944
945- 976
977-988
989-1024
1025-1034
1035-1068
1069-1094
1095-1130
1131-1162
1163-1220
.1221-1246
1247-1258
1259-1274
1275-1296
1297-1362
1363-1410
1411-1420
1421-1430
1431-1458
INDEX
For Quick Reference in Answering Your
Questions or Problems.
This index is one in which every item is indexed in several ways as:
1, direct; 2, indirect, and 3, cross. That is, they are indexed under chapter
headings; 2, indirect or independently as for instance "steam engine,
3 cross, as "engine, steam." Accordingly if the item be not found under one
heading, look up some associated heading.
""
or
By intelligent use of the index, the reader will have no difficulty in
finding any item, and if he will carefully read the index he will be amazed
at the vast amount of information to be found in this book, and he will
in this way find numerous items he would like to look up.
A
Abnormally high water...
Absolute zero......
Adjustable lost motion.
Admission.
inside.
period of..
AIR..
absolute zero..
Boyle's law.
Charles' and Boyle's laws.
Charles' law...
compression of.
def.....
effect of elevation.
free..
in water..
lowest temperature.
normal....
pressure variation.
properties of, table.
standard...
weight..
· ..
·· •
Boyle's law..
centrifugal.
Charles' law...
compound..
• •
•
•
•
•
• • •
•
• ❤
AIR COMPRESSORS.
actual, ill...
adiabatic.
air cooled.
Boyle's and Charles' laws.
application of.
•
• ·
·
• •
►
• • ·
·
.404
1005
1006 1007
•
...327
8, 14
·
•
·
.1006
11-16
.8, 14
.14
.14
.14
.13
·
.11
.12
.13
•
.29
.16
13
11
.15
.11
.13
1221-1246
1228
.1226
.1239
1227
· •
..
•
•
.1227
1223
1233
1226
.1237
Air Compressors—continued
compression cycle..
direct connected.
duplex....
diagrams.
•
frame construction.
free air..
how driven.
isothermal compression.
low, medium and high pressure.
ratio of compression.
rotary...
single, and double acting.
and multi-cylinder.
stage.
•
•
stroke.
tandem, three stage.
two stage belt driven.
*
...
•
..
two stage, three stroke cycle
types of....
valves, channel.
feather..
finger.
plate.
ring disc.
water cooled.
• •
Air pumps.
calculations.
•
·
•
J •
▸
dry.
Graham "zero clearance'
reason for...
Alkalinity, equipment
test....
+
Alleged nipple holder.
Allen valve, movement, ills..
•
·
·
•
•
►
•
1223
1235
1242
1245
1240
1221
1235
1224
.1234
1224
1233
.1230
1236
1231
1222
1244
1243
1 ·
•
•
•
•
•
·
..1241
1229
.1240
1238
1237
1239
1239
1238
.9
.723
..684
.695
675
474
.475
..913
.1017
•
·
·
•
·
•
Alternate, side spread firing.
Angular advance.
Apparent cut-off.
Ash...
pit doors
•
Ashes, def. .
Atmospheric pressure
effect on engine.
how measured..
Atomizing oil burners.
Author's, low level air pump.
Automatic injectors...
B
Bagasse.
Balanced, slide valve.
Barometer..
..
• • U
tail pipe...
types.
Barrus test.
BASIC PRINCIPLES,
absolute zero....
· · •
pressure table..
Barometric, column.
Barometric condenser(s)
starting.
•
•
•
❤ ••
•
··
•
atmospheric pressure.
barometer.
condensate.
condensation.
efficiency.
energy..
expansion, and contraction
linear…….
volumetric.
Fahrenheit scale
•
•
molecule...
potential energy
power...
• • •
sensible heat.
specific heat.
steam…..
temperature.
thermometer.
scale...
vacuum..
•
•
·
• •
•
•
· •
foot pound..
friction..
gauge and absolute pressure.
heat...
and work..
horse power.
kinetic energy
latent heat.
•
►
·
•
• •
•
pump, so-called.
..
D
pressure..
from barometer reading.
·
· ·
• ·
•
•
•
•
•
·
• •
304
1031
1006, 1007
·
•
•
•
.93
5, 12
.5
5
•
.73
302
·
•
623
692
494
78
995
··
680
688
712
689
689
673
1-10
•
.8
5
6
.9
.9
10
4
10
10
10
•
•
•
•
·
•
10
6
2
3
.5
4
2
1, 2
4
4
5
7
2
3
8
2
8
8
6
7
.8
4
•
•
•
6
9
Basic Principles-continued
work.
Bastard condenser, application of.
Bending stress..
BIG BOILERS.
· ·
baffles...
baffling.
· · • •
bent tube.
development, ills.
circulation..
forced circulation.
hand hole assembly, ill..
large straight tube..
marine header...
sectional header, ill..
sizes....
tube header, ill..
connections..
•
..
steam and water drum, ills..
straight tube.
• •
..
draught
Scotch..
sectional..
tube sizes.
two inch tubes.
types...
water cooled furnaces.
Bilgram diagram, ill..
Bleeder.
Blow down regulation.
Blowing off…….
Blow off valve..
precaution with.
Boiler(s), circulation in .
► •
Clyde, and Scotch.
dry back....
·
D
•
• •
+
• •
• ·
•
•
•
•
•
•
··
·
construction, angle stay.
crown bar..
Graham vertical.
horizontal return tubular.
horse power of……..
locomotive.
non-sectional.
patches..
pipe.
plates, how tapped.
room.
• ·
•
•
•
•
•
sheet repair...
shell, half section, ill
·
• .
•
• •
•
+
··
·
jaw stay..
stay tube...
submerged tube.
through tube..
tubes, properties of.
water required...
where located.
BOILER ACCESSORIES . .
buoyancy float regulator.
collectors..
dry pipe..
•
•
·
·
•
691
..145
777-798
•
•
•
•
•
.780
.789
785
.783
.785
..798
..782
777
•
..782
..779
777
779
..785
..781
.793
789
•
..792
..777
4
.793
.1019
..328
470
..337
253
339
25
•
112
.120
.171
172
.116
110, 119
129, 355
.111
114
352
.126
161
298
298
119
114
351
220
.170
.170
.115
115
•
•
•
•
•
•
.361
..299
292
277-290
.283
. 288
..287
།
Boiler Accessories—continued
feed, water heaters.......
278
Graham separator collector and dryer. 286
heaters, open and closed..
..279
saving.
pumps..
separators.
steam, loop.
•
• •
•
• .
•
separator.
traps.
water regulator.
BOILER CALCULATIONS.
• •
-
boiler tubes, properties..
Code, horse power rating.
rating, objection to...
evaporation...
example and rules..
grate, diameter of.
dimensions.
• •
adjustment.
operation.
•
·
•
heating surface.
horse power..
properties of circles.
size of grate..
tubes, diameter of...
tubular heating surface
BOILER FEED PUMPS.
adjustable lost motion..
centrifugal...
turbine driven.
characteristics.
combined auxiliary valve.
operation..
compound.
cushion valve.
•
•
gear..
power.
system.
• • •
valve, and port.
turret...
• · •
·
enclosed impeller.
engine driven...
feed water.
• ·
list of parts.
maximum lift.
•
•
systems..
five, ports, why?.
hot water.
independent.
internal gear.
jerky operation.
Kinghorn valve.
lack of capacity.
lift...
· ·
• ·
·
def....
duplex, "D" and "B" gear
• •
·
•
•
• •
• •
•
•
· ►
• D
▸
•
stage, ills..
Graham engine driven, ills..
•
►
··
•
+
•
•
·
DI •
•
•
•
• •
•
..285
289
.287
.284
.283
355-370
361
369
369
355
364
.357
.356
360, 366
355, 366
..358
.356
362
363
•
·
•
•
371-432
.404
374
.412
.375
.389
390
.383
.397
418
.398
.371
406, 407
•
280
277
.401
.413
.394
397
377
374
.373
.371
•
·
.382
395
422
.384
.413
.373
.425
417
381
422
.380
.415
412
*
Boiler Feed Pumps-continued
multi-stage impeller, ills..
negative lift...
non-expansive valve.
operation, valve gear.
pot valve type.....
pound and vibrate, cause.
priming valve…………
reciprocating pumps.
selection of……
separate auxiliary valve.
servicing valve gear.
short stroking..
simplex, construction.
gears...
horizontal, ills..
steam valve type.
system..
•
•♥•
•
worn-sealing rings.
Boiler feed water.
chloride test..
equipment..
hardness test.
taking sample.
testing..
•
•
vs. duplex pumps.
single stage..
size required..
split cross head.
starting..
stopping on dead center.
reciprocating pump troubles.
transmission.
•
triple expansion.
types...
valve gear "lost motion'
vapor lock..
various drives, ills..
water piston.
blow off valves...
check valves...
cock operation.
fusible plugs.
gauge cocks..
globe valves.
goose neck.
grate.
injector.
Mississippi cock.
gauge...
stop valve.
•
·
safety valve.
steam, cocks.
ATTACHMENTS..
• •
•
test kit..
BOILER FIXTURES AND
D • • •
·
• [ •
►
· •
• •
·
•
• •
waste cock.
water, column.
•
straight way cock.
valves...
•
•
·
D
•
•
·
·
• •
.
❤
•
•••
•
•
•
420
.413
399
388
.377
.416
420
.371
.383
386
417
416
.372
385, 392
.396
.391
384
.376
421
.380
379
.416
419
412
.377
383
.371
402
417
.418
.379
422
469
476
.477
470, 473
.472
470
471
·
•
a
·
*
•
•
•
•
245-276
251, 253
248
260
272
261, 262
250
269
273
·
T
+
•
•
· •
•
.270
262, 263
246
255-265
266, 268
247
254
245
261
264, 267
Boiler Fixtures and Attachments—cont.
gauges...
whistles...
BOILER MATERIALS.
defs....
BOILER OPERATION.
action of zinc..
after lighting fire.
ash pit doors..
avoiding blowing off.
before steam forms.
bleeder operation.
boiler, and engine
blowing off...
"boil out"
...
where located.
cleaning, boiler.
fire..
coal tar firing.
coke firing.
coking method...
••
•
• •
• •
•
•
•
··
feed pump indication.
filling boiler.
fire tools...
•
condenser connection.
continuous water feed.
corrosion..
“cutting in” a boiler.
draught in boiler room.
eliminating scale.
even spread...
exhaust piping.
··
firing, coarse coal..
improper position.
intervals..
•
""
•
with coke.
with sawdust.
with shavings.
with straw.
• •
•
•
·
•
•
• •
with tan bark.
foaming, ills...
formation of scale..
•
• •
• •
locomotives.
methods, front and back.
side spread...
with coal tar.
•
in boilers.
laying up..
"lively gauge’
main steam outlet.
oil, effect of……………
piping methods.
• •
*
•
• •
•
· •
·
•
•
•
incrustation..
installation....
intermittent water feed.
intervals between cleaning.
kerosene.
•
•
•
·
•
•
•
263, 266
.274
·
139-140
.139-140
291-344
·
· ·
..300
327, 328
. . 293
337
341
292
.339
311, 313
.314
314
.304
296
326
332
342
298
336
303
297
329
299
303
308
308
..319
321, 327
.304
•
gauge cocks..
Graham separator, collector and dryer.325
hand firing methods..
•
•
.335
300
.302
.302
►
·
.304
314
314
316
316
.315
..317
•
•
•
•
331, 343
335
.301
303
335
292
327
.312
336
.336
.341
.302
. 295
•
•
.335
. 294
Boiler Operation-continued
pitting.
points on hand firing.
port opening....
D
precaution with blow off valve.
preventing vibration.
priming and foaming.
proper water level..
regulating draughts.
right and wrong piping.
running.
•••
scum scoop..
soot indication.
stack observation.
indication
working
•
washing boiler.
water, column, ills.
dangerously low.
gauge....
starting the fire..
steamer "Atlantic City"
thin fuel bed…….
thin spots...
· •
• • ·
repair of.
cutting tube.
•
wet and cold...
BOILER REPAIRS.
• •
··
•
•
•
air leak detector, ills...
beading tool...
before making.
bulge....
breakdowns
caulking.
tool.
cracks.
•
•
•
·
O
wrong method.
BOILER TYPES
split tube..
tube, plug, ills..
stopper.
•
•
leaky tube, ill...
ordering new tubes.
patches, soft and hard.
preliminary operation.
removing, furnace, ill
nipples..
tubes
ripper chisel...
rolling tubes too much.
round methods..
•
• •
• •
cylindrical furnace removal.
grooving...
classification...
Clyde (dry back)
dampness...
double tube boiler.
dry back...
soft and hard patches..
spectacle piece, ill...
• · •
•
• • · •
•
·
..
·
•
•
•
+
·
•
•
• •
··
•
• •
•
•
·
•
•
•
▸
•
•
•
•
.334, 335
318, 319
..380
339
295
331
• •
.323
.321
291
.296
336
333
320
299, 300
.310
.308
307
• •
• ·
•
·
•
• •
+
339
.324
330
:.301
302, 324
.325
..309
345-354
·
345
349
..346
347
.346
.352, 354
354
347
347
.350
346
346
347
353
352
346
346
.350
.353
349
353
345
•
•
•
•
•
•
•
•
•
.353
351
349
·
•
.347
.348
..345
109-126
.109
.120
.334
114
.112
•
Boiler Types—continued
externally fired..
fire, and water tubes.
box shell boiler.
tube...
flash and semi-flash.
flue fastened..
Galloway tube, ills..
. 121
.126
generator.....
Graham super steam generator, ills...124
Graham vertical...
.116
119
122
.118
111, 117
.114
•
locomotive...
non-sectional
pipe boilers.
porcupine.
Scotch..
sectional..
•
*
horizontal return tubular.
internally fired……
link suspended.
•
• •
.. •
•
•
• • ·
•
single tube boiler.
submerged tube.
through tube..
tube and flue.
variety of.
water, back.
tube...
• •
•
• · •
•
•
•
•
·
•• •
• ·
•
"Boiling out"
Boiling point.
Boyle's law.
Box condenser, author's.
B. t. u....
•
· •
• •
··
• •
Bursting pressure.
Butt and double strap joint,
various types..
•
•
C
Calculation of riveted joints.
Candle flame
Carbon..
dioxide.
monoxide.
Caulking, how done
• D
Centrifugal pumps.
natural balancing.
troubles, failure to discharge
lantern ring.
noisy operation.
packing...
Charles' law..
Checker work, cooling tower.
Check valves.
• · ·
•
·
•
•
•
•
Chimney, object of.
Circulation, in boilers.
Circumferential joints.
Classification of boilers.
Cleaning the fire...
·
• •
··
•
• ·
• •
..
• • •
•
•
..
•
123
113
112, 117
.110
126
114
•
• •
•
.126
.121
119
114
114
.115
115
110, 113
.109
112
110
341
23, 44
14
.693
59
,215
-
..
•
→
•
•
•
•
•
•
.221
•
222
.86
.82
.85
85
354
.374
421
.419
423
.423
423
14
•
•
體
​•
.764
..248
.547
25
•
..239
.109
311
Clearance..
linear.
Clinker....
··
Closed heaters.
Clyde, and Scotch boilers.
dry back boiler..
•••
·
Coal, and oil, table..
heating value of.
how graded...
sizes of...
tar firing..
•
· ·
Coefficient, of elasticity
of linear expansion.
Coffee brewer.
Coil, with return bends.
Coke..
firing.
heating value of..
Coking method.
Cold, short.
··
•
ashes..
carbon.
dioxide.
monoxide.
· ·
• •
•
.
..
CO2 recorder..
Davy's lamp.
def………….
flame...
•
• •
··
• •
clinker...
combustible.
complete.
constituents of ashes.
•
shut..
Collectors...
Combination cooling tower.
COMBUSTION.
·
•
· • ·
• D
hydro-carbons.
hydrogen....
incombustible matter.
incomplete.
kindling point.
oxidation..
•
•
• •
·
• ·
• • • •
•
•
··
• •
• • • ·
•
·
·
Orsat apparatus.
• D
oxygen, how obtained…….
perfect..
products of..
•
•
•
·
Ringelmann chart.
smoke scale..
smoke...
cause of...
supporter of…….
· • • • • • •
too little air..
volatile matter.
Compound feed pumps.
Compression..
•
··
•
•
effect of...
loss due to..
position..
COMPRESSOR CONTROL
DEVICES...
...
•
•
•
•
•
•
•
.1008
1008
•
•
•
•
•
•
.95
445
112
.120
..80
75
74
74
314
148
.65
.25
897
75
•
•
•
•
•
.314
..76
.304
141
142
.288
..763
81-96
•
體
​85
85
.95
81
85
..95
95, 96
.88
81
.87
84
83
.93
85
•
..93
..82
•
•
·
•
•
•
.84
81
•
94
81
.87
.85
93
92
..89
.91
81
85
..90
.383
146, 1011
.1012
..1015
1010
•
1259-1274
Compressor Control Devices-continued
actuating force......
automatic clearance valve.
auxiliary valve…..
constant speed..
dual control..
free air unloader.
indicator diagram.
inlet unloader..
necessity for..
safety stop valve.
stop and start..
1260
1270
.1272
.1265
.1263
1263, 1272
.1269
1268
1259
1272
1261
1264
.1262
operations..
unloading methods.
valves, cylinder relief.
1263
1271
safety stop..
1272
1267
variable, clearance, diag..
compression, diag....
COMPRESSOR OPERATION 1275-1296
.1267
.1295
belt driven compressors..
belts.
.1287
by-pass system...
1284
cold weather precautions.
.1293
..1285
1292
1291
1282
1286
.1276
1277
1290
..1289
1288
1281
1279
1275
•
• •
...
· •
•
unloader, adaptation.
•
cooling water..
cylinder, cleaning.
stuffing box..
five step control..
"four corner”…….
intake piping..
lubrication.
oil, stuffing box.
wiper rings.
partition plate.
parts list.
plug and bolt...
preliminary procedure.
principle of...
regulator, five step.
remote control..
removal of oil.
starting.
•
❤
•
•
• •
•
▼ •
•
• •
·
•
...
precautions.
steam driven.
suggestions..
variable clearance.
Condensate..
... •
pumps....
Condensation.
• •
•
•
cooling, surfaces..
water required.
design data...
dry air pumps.
Grashof formula.
high vacuum.
•
▸
•
• •
•
•
+ •
• •
·
•
•
•
• •
•
• ·
..
··
·
•
•
•
·
·
• •
•
•
·
•
•
·
•
•
•
•
•
•
·
.1280
1284
.1284
1287
•
1275
.1277
1295
.1294
1279
causes of....
initial....
Condenser and pump assembly, ills....696
CONDENSER CALCULATIONS.713-730
air pump, jet condenser.
•
• •
• • •
729
.9
.43
.1005
·
..723
716, 720
..9
•
..715
.718
729
..721
728
•
•
Condenser Calculations-continued
injection water.
range of vacuums.
terminal difference.
vacuum available..
velocity of flow.
water works..
wet air pump
CONDENSERS.
air pump
function of.
·· •
low level, ill.
••
Barrus tests...
box...
•
•
• •
• •
reasons for..
automatic cut off diagram.
·
..
• • •
• •
•
economy of.
jet, elementary, ills..
Condensers, keel..
parallel flow...
power gain in condensing.
scoop..
• •
· •
•
·
• ❤ •
so called vacuum pump.
standard, ill..
steam turbine..
·· •
·· •.
·
throttling diagrams, ills..
vacuum, def..
•
how measured.
Condensing, gain in power.
object of...
Conduction.
Conductivity.
Constant feed,
Convection...
current..
cause of...
COOLING PONDS AND
· •
• •
TOWERS..
Cooling Ponds, def..
directed flow, ills...
•
·
••
...
+ •
distribution deck..
double deck spray, ills..
effect of weather.
loss...
louvre fence.
natural...
•
• •
*
•
combination, ills..
construction..
•
+
•
non-directed.
single deck spray, ills..
spray, cooling surface.
depth of.
nozzles, ills..
spraying action.
types...
where suitable.
Cooling surface, condenser
Cooling Tower(s)
• •
·
draught calculation.
enclosed..
•
• •
•
•
•
•
·
··
•
•
•
•
•
•
723
.717
..716
.713
.723
..720
.726
671-712
•
·
..
..674
..692
.675
.674
673
.693
672
..678
691, 692
.679
673
•
.694
.676
694
•
.718
672
.671
.676
.673
.671
..68
.68
326
.68
.97
...98
747-764
747
.749
..756
751
.750
..747
·
9
*
•
753
.749
748
.750
..751
.754
..752
..751
749
747
.716
.755
..763
756
..759
..758 .
•
•
Cooling Tower(s)-continued
forced draught...
induced draught, ills...
open natural draught, ills...
wood checker work, ills..
Cooling water.
Corrosion..
•
in marine boilers.
•
operation.
troubles...
Counter flow condenser, ill.
Cover plate...
Crank position, ill.
Cross flow condenser.
Crow foot stay.
Crown bar...
Cushioning.
Cut off, apparent.
Cylinder, head, striking.
plan view, ill..
section of, ill..
•
def...
•
► ..
• •
** ·
• ·
D
D and B pump valve gear.
Data on name plate.
Davy's lamp...
Deep well pump(s)
attention required.
installation.
•
· ·
• • •
· •
•
• •
pre-combustion.
separate...
turbulence.
•
•
. •
... •
•
•
•
•
•
·
a
• •
• • •
•• •
·
abnormal power.
does not start..
low pressure..
no discharge.
Deep well system.
Deformation.
Diagram, Bilgram, ill..
Diagonal stay.
DIESEL ENGINE PERFORMANCE,
....
critical comparative analysis ..1411-1420
cycle or system...
1419, 1420
fallacy of compounding.
DIESEL ENGINES...
admission stroke..
alleged "full" Diesel.
alleged "semi-Diesel”
combustion, methods.
periods..
•
· •
• •
·
•
•
pressures.
stroke..
combustion chamber, air cell..
alleged "open".
ante...
plain
•
·
..762
760
.757
..764
..715
332, 333
.470
.704
157
.1018
703
.169
172
·
.1012
1006, 1007
.416
.991
.990
•
▸
·
.406
.178
..88
430
432
430
430
427
427
427
427
427
429
.147
.1019
.167
•
•
•
•
• •
•
•
1416-1419
1363-1410
•
•
•
•
• 4
•
.1366
1363
1363
1383
1380
.1369
..1367
•
•
·
*
1385
1381
.1385
1381
.1382
1382
.1381
1363
Diesel Engines-continued
distributor system..
exhaust stroke..
four cycle....
fuel injection, methods..
systems.
fuel pumps.
glow plug.
Graham injector, operation of...
Graham mechano, acto transfer
injector..
hydraulic valve.
indicator diagram..
individual pump system.
injection, nozzles..
valve, mechanical.
lubricating oils...
operating instructions;
troubles.
overloading.
··
•
··
power stroke.
Raabe on idling.
two cycle....
·· ■
•
• •
operating instructions
operation..
super-charger.
timing diagram.
viscometer..
Directed circulation.
flow, cooling ponds, ills
•••
•
•
mechanical.
methods..
advantage of.
coal burned..
installation.
advantages.
tube condenser, ills.
water tube..
Down flow boilers.
DRAUGHT…..
•
• ► •
•
• ·
·
•
•
•
causes of...
chimney draw.
closed stokehold, ill..
curves, ills..
def.....
forced...
•
•
..
·
• ·
•
•
·
·
1404
1401
101
.749
Disengagement, steam bubbles. ..101
Distribution, deck, spray pond, ills....756
of steam..
Double, deck spray pond, ills.
flow turbine condenser, ill
riveted joint.
shear....
→
• •
-
►
·
·
•
•
•
•
·
•
·
..
·
•
*
•
gauge, indications
U type, ills..
Graham special engine, ills..
how measured.
induced..
installation, forced draught, ills.
marine practice..
• ·
•
•
.
•
·
.1377
.1369
1366
.1370
1386
1387
.1392
...1379
*
· •
.1378
.1387
1364, 1365
.1375
1390
1388
1400
4 •
·
D
•
• 1
1393-1398
.1400
1368
1398
.1403
1405-1410
..1404
1403-1405
•
• •
·
•
+
•
•
•
·
• ·
•
•
•
•
..989
..751
.707
.228
.150
.158
.697
.114
..209
547-556
-
·
►
•
•
.547
548
.552
549
547
553
·
550
556
553
549
548
555
550
554
.552
554
•
•
•
•
• •
550
551
Draught-continued
……….
natural, coal burned..
ordinary jet blower, ills..
primary air supply..
secondary air supply.
steam jets.....
stokehold system.
turbine blower, ill..
two kinds...
vortex blower, ills..
Drilled stays, precaution.
Drill sizes for pipe taps.
Dry, air pump..
bottom fire box.
system....
valve and valve seat.
Duplex pump..
small, ill………..
valve gear.
entire..
“lost motion”
rocker arm, ill..
Duty of boilers.
Eccentric.
strap...
Eccentricity.
ECONOMIZERS.
construction.
Dry steam……….
Dual bank condenser, ill..
Ductile...
Duplex, "D" and "B" gear.
•
...
arrangement, ills.
• •
..
D •
•
•
•
• •
Efficiency.
• • •
of joint.
Ejectors, steam.
Energy..
kinetic.
potential.
• • ·
• • •
• •
•
• •
•
D
·
• ·
· • •
def....
economy.
feed pump.
header type.
late practice.
marine stud type.
return bend bifucations type.
Edges of valve..
•
.
•
E
· •
· • •
.
•
•
•
• •
· •
•
Engine driven feed pumps
Equal lead....
Evaporation rate.
Evaporative condenser
EVAPORATORS..
connections.
construction.
def………….
•
·
•
•
•
555
551
548
.548
551
553
.554
.550
.550
165
..914
684, 789
117
.33
.706
142
406
•
•
•
•
•
.278
277
406
.406
..402
1129,1130
401,
•
·
· •
• •
•
•
·
•
•
.394
397
1030, 1031
.1029
1031
.451-458
453
451
458
453
452
457
454
457
.992
.10
214
684
4
.4
4
.371, 378
1003
.133
..700
765-776
·
•
1129
127
·
•
..769
..773
765
•
Evaporators-continued
distilled water installation,
essentials...
fittings.
installation, ills..
methods, ills..
operation..
salinometer.
• D
• ...
scale marking.
single and double effect, ills..
typical.
various methods.
•
Even spread firing.
Exhaust, edge.
lead...
.. •
• · • · •
provision for.
volumetric..
piping.
Expansion, and contraction
linear.
systems..
types...
def...
•••
....
External latent heat.
Externally fired boiler.
Extreme position, ills..
deaerating
metering.
• ·
• •
• •
• •
•
•
Factor, of evaporation..
of safety..
Fahrenheit scale.
Feed, constant..
intermittent.
Feed pumps, characteristic.
drives for..
indications.
kinds used.
simplex double deck plate.
size required.
•
• •
• •
construction.
•
•
•
•
•
• •
• •
•
•
•
•
F
··
•
•
·
D
•
•
·
•
•
• •
·
·
•
Feed water…….
FEED WATER DEAERATION...459-466
air separation.
cycle...
deaerator, location
def....
essentials.
marine type.
process in detail.
FEED WATER HEATERS.
blowing. down..
classification..
cleaning.
...
coils, material.
closed..
•
•
•
•
·
•
•
•
..767
.766
.771
.768
.770
.765
.772
774
•
• •
•
·
•
•
..993
.1003
.297
· •
10, 66
.10
.65
.10
38, 39
56, 57
147, 217
8
326
327
.375
•
·
.766
.774
.775
.303
·
•
.123
1013
•
•
.377
.329
371
372
380
.382
277
.371
•
.460
.464
465
459
.460
462
.460
433-450
•
344
433
. 449
.447
443
445
441
450
433
Feed Water Heaters-continued
87
Flame.
economizer.
elementary..
open....
marine type..
maximum temperature.
mistake in buying.
multi-stage system.
object of..
··
and closed.
...
• •
• •
·
•
·
testing..
kit..
་ ·
primary..
regenerative system, diag.
repairing.
saving..
secondary..
semi-closed feed system.
single stage feed system..
test for leaky coil...
FEED WATER REGULATORS..479-488
buoyancy float..
evaporation.
type.
expansion, tube.
tube inst..
type.
intermittent feed..
··
•
equipment.
foaming..
hardness, test..
alkalinity, tests.
equipment..
blow down regulation.
boiler water..
chloride test.
..
• • •
• •
test equipment.
importance of.
specific gravity body.
FEED WATER TREATMENT.
• •
·
•
.. .
leaky condenser test..
selecting the treatment.
standardized solutions.
tests usually made.
total alkalinity.
•
•
• •
•
• ·
•
•
•
• •
• •
•
•
·
Field drop tube.
Fire, door..
tube ..
Firing methods..
front and back.
on steamer "Atlantic City"
with, coal tar.
coke...
saw dust...
shavings.
straw...
tan bark.
Fittings, joint and edge.
without pitch, drunken thread.
Fixed carbon...
· •
·
·
• •
•
•
•
•
·
·
433
434
441
443
447
446
435
437
279
. 433
448
·
449
280, 435
433
442
444
447
+
• •
480
483
.487
484
.488
488
479
480
•
•
467-478
.470
469
476
477
470
470
473
.467
478
467
468
470
471
468
.476
.106
..182
110, 113
•
·
474
475
..306
..304
.310
..314
314
316
•
..316
315
.317
.938
824
73
•
•
Flash, boilers.
generator..
Flat, flame oil burners
surfaces.
Flue..
Foaming
ills...
Foot pound.
Force.
•
Formation of steam.
Free air..
• •
·
Freezing, and boiling points
point....
of sea water..
Friction..
•
From and at 212° Fahr.
FUELS..
..
anthracite coal, sizes. .
bagasse...
bituminous..
burned....
coal, and oil, table.
constituents..
coke...
uses of..
crude oil.
def...
fixed carbon..
▸
·
•
Fusion...
•
•
·
· A
•
•
•
gaseous, liquid comparison.
hard..
heating values.
how classed..
liquid.....
natural gas, heating value.
•
oak bark..
oils, classifications.
•
··
plug, location
•
peat....
petroleum.
saw dust, heating value.
soft..
straw.
tar..
total combustiles..
volatile matter...
wood, heating value.
Furnace, internal boiler
Fusible....
• •
latent heat of.
work of...
·
·
•
·
• •
•
•
•
•
•
·
·
•
•
•
..633
161, 238
113, 243
135-343
.331, 470
4
147
36
13
.18
66
24
•
•
.209
126
·
•
.10
.57
73-80
.75
.78
C
•
·
.75
131
.80
.73
.75
75
..75
73, 75
.74
78
79
77
.613
76
79
77
75
77
.78
78
.73
73
79
+
•
•
.73
73
77
•
.137
142
177
20
.20
.23
G
Galloway tubes, ills..
GAS ENGINE PRINCIPLES...1297-1362
121
Gas Engine Principles-continued
abnormal events..
post-admission.
post exhaust.
pre-release.
review..
adjusting tappet.
admission..
stroke.
•
air bleed...
arc and spark.
broken valve springs.
cam drive, action of.
shaft drive.
carburetor(s)..
accelerating unit.
anti-percolating unit.
elementary..
thermostat...
crank shaft..
cycle.
def...
•
essential elements.
idling system.
metering rod..
•
•
• •
………
• •
•
•
·
..
• ·
•
slow closing throttle.
variable air bleed..
compression..
stroke..
connecting rod…….
cooling control.
thermostat...
•
• ..
•
·
cooling systems.
details...
latent and sensible heat.
natural circulation..
D
•
diagram showing parts.
drop....
• •
+ • •
· • •
[
•
•
· •
economizers.
events of cycle..
exhaust stroke.
explosive mixture.
four cycle..
fuel mixture..
full pressure lubrication.
hopper cooling..
igniter....
ignition, condenser, hydraulic
analogy..
high tension.
low tension.
make and break.
primary coil.....
•
• •
• .
lubricating systems.
full pressure…..
• • • •
·
··
• •
•
•
•
synchronous, musical analogy.
indirect air cooling.
inductive admission.
inherent defects..
lean mixture.....
· •
1309, 1317
.1309
.1309
.1309
1318
•
•
.1322
1317
1303
1343
.1352
1301
1321
1323
1338
.1346
.1346
1340
1339
.1344
..1345
1346
1347
•
+
•
·
•
..1302
1336
1337
1331
•
·
•
•
1332
1333
1335
1336
1302
1300
1297
1298
1307
..1344
1316
.1308
..1338
1300
1338
1329
1337
1352
.. • •
.1318
1304
·
·
•
+
•
·
•
•
•
1359
.1316
.1353
1353
1359
.1360
..1334
1319
1310
.1339
1328
1330
•
•
• •
Gas Engine Principles-continued
lubrication, gear and chain.
mixture proportions..
moving parts.
multi-cylinders.
valves..
.. •
..
normal, and abnormal events.
events...
plain tube carburetor.
poor mixture.
port opening.
post-admission.
reason for...
power stroke..
pre-admission.
reason for...
pre-post events.
pre-release.
primary air.
release proper..
rich mixture.
scavenging.
secondary, air.
ignition coil.
slow closing throttle.
stationary parts..
super-charger(s).
types.....
synchronous ignition.
systems.
condenser.
•
in head.
•
► • ·
·
· •
Gear pump.
operation.
Generator..
flash..
semi-flash.
•
• • •
• • •
·
• ·
•
•
·
•
•
shape of...
where located.
·
•
•
• •
·
terminal pressure.
timing, gears.
marks..
valve, and valve gear assembly
drive..
gear...
spring.
timing..
timing diagrams.
··
•
•
•
weak valve springs.
wire drawing.
Gaseous, fuels.
steam
•• •
· .. •
·
•
•
•
•
Globe valves……
Gozenbach valve, ills.
•
•
•
+ •
·
·
•
•
Gas liquid comparison.
Gas, natural………
Gauge(s), and absolute pressure
water....
·
• •
•
•
•
• •
·
•
•
•
►
•
•
→
·
·
•
•
1317
1319
1318
1307
.1341
..1318
1338
1320
1341
1355
.1346
1299
1348
1361
1359
.1351
1357
·
·
•
.1331
1338
1299
.1310
1317
1317
1342
1339
.1313
.1317
1319
1306
.1307
..1327
1301
1313
1313
1316
1323
.1301
1324, 1326
..1312
•
·
•
•
•
266
.426
424
126
.126
126
.250
1048
Goose neck.....
..269
Graham, separator, collector and dryer. 325
•
1315
1315
1314
. 1323
1319
79
.33
.79
79
•
•
.6
Graham-continued
super steam generator
vertical boiler..
Grashof formula.
Grate...
air space..
function of ....
heating surface
ratio..
shape of....
Gun oil burners.
Gusset stay…….
•
Hand firing.
Hardness.
test..
• *
Hard patch.
Head..
HEAT....
two kinds of.
and work.
B.t.u..
•
•
radiation..
sensible...
specific.
•
•
•
· ·
coefficient, of expansion
of linear expansion.
4
•
·
temperature
scales...
•
conduction..
conductivity.
convection.
def....
expansion, and contraction.
due to...
external latent.
freezing point.
internal latent:.
judged by color
latent....
mercury well..
molecular vibration.
·
•
•
·
•
..
•
·
·
•
•
•
1]
• •
H
•
•
•
figuring radiation.
heat, how lost.
proper radiation..
radiators, table of..
simplified methods.
240 B. t. u..
Heating surface.
amount of.
arrangement of.
·
·
• •
•
•
+
+
•
•
·
•
•
• •
·
❤
·
124
116
721
127
.133
.130
.131
128
130
.633
166, 169
•
•
·
•
303
.142
473
352, 353
..27
..28
.59-80
.3, 4
59
•
•
•
transfer of.
unit of...
HEATING CALCULATIONS……..859-882
basis of...
Code methods
•
.59
66, 67
..68
..68
.68
..64
...38
•
.65
.65
■
3,70
.60
.61
.3, 68
..59
+
..68
2. 62
•
.66
•
38
64
.2
•
•
•
..859
864-882
860
859
863
.863
.861
861
127
131
132
.65
.59
Heating the feed water.
Hints, on locomotive firing.
HOIST(S)
air..
boiler.
size...
brakes.
bull wheel.
•
•
•
••
U
··
chain drive..
clutch winches...
comb. drum and brake.
construction details..
defects of gasoline and Diesel.
def....
Diesel.
double friction cone.
drum, diagram.
types..
electric..
double drum.
swinger.
•
•
•
...
·
··
•
engine disassembled.
exhaust piping.
four sides...
friction, drum.
leaders.
gas hoist brake.
gasoline...
derrick lighter.
multi-drum.
•
•
Homogeneity.
Homogeneous.
•
•
•
•
··
•
• ▸
•
•
•
O
oil on brake.
operating, directions.
gear..
•
•
safety lever.
single cylinder..
swinging gear.
terms.
two drums.
winch operation..
Hollow screw stay, ill.
• •
overhead system.
pitch for main..
•
݂ܕ
•
•
...
• •
•
absolute pressure..
circuit two pipe system.
distribution tees…….
expansion tank…………..
feature of...
natural circulation.
one pipe..
•
•
..
•
•
• •
•
· •
•
· • •
•
•
•
storage tank..
thermo circulation.
two pipe natural circulation.
•
435
..321
1131-1162
1161
. 1131
1131
1144
.1148
1154
1144
1142
1143
.1159
1131
1158, 1159
.1155
1140
1138
1160
1160
1162
1134
•
•
•
•
•
•
•
•
•
•
•
•
•
•
·
·
1135
1133
1136
1141
.1155
1154, 1157
1156
1147
1145
1149
1148
1151
1137
1146
Horizontal return tubular boiler. 110,119
Horse power.
boiler..
Hot short.
HOT WATER HEATING.
•
·
•
•
·
•
•
·
•
.1151
1132
1148
.163
.152
142
•
5
130, 355
.142
847-858
..855
.856
849
.852
.847
840
.851
.853
.858
.849
.848
.857
•
•
•
·
·
•
·
·
HOUSE HEATING BOILERS...
BOILERS...799-814
alleged cast iron, objections.
Code rating.
coil, ill...
diaphragm regulator
heating surface.
def....
..
inadequate..
manufacturers rating.
old rating...
sectional welded..
short and long pass.
square base....
•
unsatisfactory operation.
vertical, cast iron.
tubular.
[ •
basic principles.
"boil over".
circulation…….
convection currents.
directed flow..
formation of steam.
free circulation.
··
....
Ice, fusion of……….
def...
drum..
....
weight of..
Ignition, point.
**
water film.
HOWABOILER MAKES STEAM.97-108
"reversed" circulation
steam bubbles.
effect of.....
•
•
feed pump.
INDICATOR(S)
cocks ..
construction of.
•
• A
specific gravity of..
•
system oil burners..
··
• •
.. •
+
temperature variation.
undirected flow..
HOW TO FIGURE RADIATION;
CODE...
Hydro-carbons.
Hydrogen..
•
•
pantograph.
parallel motion..
piped to cylinder.
reducing motion,
removing piston.
Incombustible matter.
Incrustation..
Independent, cut off.
.
• • ·
•
I
•
• .
•
·
U •
lever reducing motion
outside spring.
•
+
•
·
·
•
•
• • •
•
•
•
..799
..801
.806
..814
799, 895
..800
..800
810
801
.812
.807
..804
..802
803, 804
..808
811
•
··
•
a
.102
..100
103
104
•
..97
101
.
•
..98
.97
864-882
84
.83
·
.101
..99
..98
102
..20
22
18
84
•
•
636
..93
.335
1049
.371
977-988
.985
.977
977
.978
.982
.986
983
•
·
.979
.985
.984
.987
Indicator(s)—continued
scale...
springs..
taking apart.
types....
Initial condensation.
@
•
INJECTORS..
automatic operation.
calculations..
•
• •
• •
••
caution.
connecting.
def……….
double tube
failures..
"Inspirator".
installation.
locomotive.
non-lifting and lifting.
operation...
over flow valve.
• ·
•
• •
· •
part's
points on connecting.
positive...
principle..
proper size.
rudimentary.
selection.
troubles.
types...
• •
•
..
Inside, admission.
lap..
lead..
•
after, coolers.
necessity for
principles.
two stage.
construction.
def.....
installation,
·
INTER AND AFTER
COOLERS.
D
•
··
+
non-photo-electric control.
non-recirculating flash boiler
photo-electric control..
recirculating flash boiler.
moisture..
mountings.
receiver capacity.
Intermittent feed
•
with after-cooler
without after-cooler.
•
•
• • ·
D
•
·
•
•
Internal, boiler furnace.
latent heat....
Internally fired boilers.
·
•
·
•
INSTANT STEAM 126A-126F
motorized valve..
+ •
·
.981
..980
.988
..979
1005
489-508
•
495, 496
498
.508
501
489
495, 506
..503
507
499
504
493
491
494
489
501
.493
489
497
491
•
•
•
•
•
*
• •
•
•
•
.490
1006, 1007
..999
1003
•
→
·
•
•
·
•
•
4
126 D
126 E
126 F
126H
126 B
1247-1258
1252, 1254
1255
1258
1253
1251
1247
1248
1257
1256
1254
1252
1257
•
·
495
505
327
137
.38
.122
J
Jet Condenser, barometric,.
column....
circulating water.
combined, flow, ills..
parallel and counter flow.
counter flow.
dry air pump.
operation.
parallel flow.
removal pump.
steam ejectors.
types..
vacuum breaker.
··
connection.
Lap.
..
..
•
•
and butt joint.
inside..
joints.
negative.
outside..
• •
exhaust.
inside...
object of
position..
variable..
Latent heat.
external.
Laying up.
Lead..
K
Keel condensers, application.
author's low level air pump.
bastard..
def...
Kerosene in boilers..
Kindling point.
Kinetic energy
··
E
· .
• •
• *
• •
▸
·
•
•
•
·
• •
Linear clearance
Link suspension.
Liquid fuel.
Load.
•
•
•
·
•
Leaking condensers, test.
Least density of water.
Length of ports...
Liberating surface.
Lift..
Lifting injectors.
Ligament..
•
·
L
• 物
​•
•
•
•
·
•
··
•
.
•
677, 682
.683
686
•
•
688
.680
690
681
683
680
684
.677
.682
.681
..684
·
• ·
•
.997
.221
..999
156, 221
..999
997
•
•
•
•
•
·
.690
.692
690
.690
.336
84
4
•
•
•
•
..1000
1003
.1003
..1001
.1000
1003
478
..23
.993
134
380
+
•
•
.2
39
341
.493
160, 236
1008
118
78
148
•
Locomotive boiler.
Loss, cooling ponds.
Lost motion, adjustable, inside.
duplex valve gear.
fixed, inside.
Louvre enclosed cooling tower.
Low level jet condenser, ills..
Low pressure oil burners, ill.
LUBRICANTS……….
def.....
desirable quality.
duty of..
friction..
•
animal oils.
choice of.
classes of....
cold, flash and burning points
crank case dilution..
•
··
••
•
cause of..
granular structure of metals.
liquid.....
lubrication..
points on selection.
S.A.E. viscosity numbers.
solid...
stability.
..
•
temperature chart.
vegetable and mineral oils.
LUBRICATION..
centrifugal oiler..
chain oiler..
chart...
compression system.
external systems.
feed regulation..
glass top cups.
•
• •
•
...
•
• •
•
grease cups.
hand oil pump.
how to lubricate.
internal, classification.
lubricators, gravity.
hydrokinetic.
down flow
up flow
plain cylinder..
multiple, sight feed oiler.
wick feed..
oil, boat feed..
cups..
pump on cylinder.
pendulum bob oiler
practical points.
pressure system.
•
•
•
4
• •
· •
•
▸
•
• •
power pump..
slide sight feed oiler.
splash system.
wrist pin oiler.
•
· ·
•
• ·
•
· •
• •
·
• • •
•
• •
· .
·
• •
► •
·
· • •
·
•
•
•
•
•
· ·
• • •
•
.402
..404
.758
..682
..631
1421-1430
.1425
1427
1424
1424
.1429
1421
..1423
1422
1421
.1421
1422
.1425
.1429
1428
1427
.1425
1424
1429
1426
1431-1458
1448
1445
1456
1452
1440
1454
1441
1452, 1463
.1437
1431
.1431
1432
1432
1434
1434
1432
1442
1445
1447
1446
1439
1449
1436, 1458
1452
1440
1450
1455
1443
· •
•
■
111, 117
.747
.404
•
·
•
·
•
·
·
•
•
•
•
•
•
•
+
•
•
•
•
•
❤
•
•
•
•
•
•
•
·
•
•
M
Manholes, shape of...
Matter, three states of..
Maximum, density of water.
vacuum condensing.
Measurement of work.
MECHANICAL STOKERS.
chain..
def...
firing..
I.F. screw feed.
•
incline..
front feed.
link grate.
underfeed.
•
•
..
ram.
rotary or sprinkler.
side feed...
single tuyere.
operating points on under feed.
over feed..
pneumatic spreader
•
•
··
•
• •
•
sprinkler instructions.
suitable fuel...
traveling grate.
under feed.
Melting points.
Mercury well...
Micro control oil burners, ills.
Mississippi cock.
Modulus of, elasticity
rupture....
Molecular vibration.
Molecule(s)
movement.
• •
•
·
· ·
•
·
N
Natural, cooling ponds.
gas..
Negative, lap.
lead, position.
•
•
Multiple spray oil burners.
Multi-stage impeller..
•
• • ·
··
•
• •
•
•
• ·
•
+
Newcomen's atmospheric engine.
Nipple holder, alleged.
replacement.
•
Nitrogen..
Non-conductor, misnomer.
Non-directed flow, cooling ponds.
Non-expansive valve..
NON-FERROUS TUBING AND
FITTINGS.
Non-Ferrous, advantages.
copper tubes, properties of.
disadvantage..
557-586
.566
..557
..303
.585
..566
..559
562
.565
...569
..559
.576, 578
.567
..564
.559
573
580
·
.561
..566
.561
21, 142
: 65
635
.263
148
149
59
1
2
•
• •
•
.181
1
23
.713
4
..
•·
-
-
•
.727
..79
..999
1001
43
+
•
..913
.350
615
420
•
..748
.399
87
.68
927-944
930
..928
927
•
Non-Ferrous-continued
edge and end feed fittings.
fittings, flared, ills..
making flared joint..
making solder fitting joint.
material..
screwed....
sizing tool..
solder fittings.
various..
hard tubes, application.
soft tubes, application.
Non-lifting injectors.
Non-sectional boilers.
Normal air....
O
··
•
• ·
•
Oak bark...
Oil, effect of..
and coal, relative values
OIL BURNER(S) ..
atomizing.
centrifugal.
chamber.
classification.
··
•
three circuits..
ejector....
flame detector.
fuel oils..
classification.
•
general principles.
gun..
hot plate...
...
master control.
service suggestions.
def…………….
domestic, automatic control.
basic.
boiler control...
connections.
installation.
•
ignition system.
induction mixing
injector.
inside centrifugal, ill..
•
•
hot water switch.
ignition transformer.
inverted...
inverted, cycle, ill.
inverted, lock out mechanism.
inverted, starting cycle.
··
·
•
•
•
·
·
+ ▸
•
operating instructions.
་
•
• ·
•
U
+
•
·
·
•
·
..937
..931
.933-935
..939
..927
.930
.936
938, 941
..937
•
.929
.929
493
114, 198
13
•
癱
​•
17
.335
..79
613-670
.623
619
.621
617
617
.646
645
.657
.658
650
.651
.652
.656
653
.651
..659
647-649
•
•
•
•
•
.616
621
.619
instructions, variable capacity type ..637
.631
low pressure, ill. .
mechanical.
622
pressure sprayer.
micro cam valve.
multiple spray.
•
•
•
•
•
.618
.659
..613
.613
.615
•
633
.622
.636
•
.623
..634
615, 625
.626
.628
637, 667
i
Oil Burners-continued
outside centrifugal……
pot..
...
proportioning.
rotary.
operation..
sprayer...
operation.
service suggestions.
troubles.
"Twinplex"
vaporizing..
··
variable capacity, ill
• •
Orsat apparatus.
Outside lap.
Oxidation..
connections, ills.
venturi, flat flame.
•
..624
614, 617, 620
637
643
633
high pressure.
632
661, 664
wiring diagrams.
One and two pass condensers, ills...701
Open, cooling tower.
heaters....
• •
Palm stay.
Patches, boiler.
Peat...
•
T
• ·
• •
·
• •
•
•
•
•
•
bending methods.
bushings..
heating value of...
Period of admission.
Permanent set.
Petroleum..
· .
fittings.
flanges.
grinding chasers.
gun tap, ills..
hcaders..
·
•
• •
• •
•
•
Pipe bends, table.
Pipe boilers..
PIPE, FITTINGS, AND PIPE
•
•
caps....
coupling
cutting, a thread
niples, wrong way
dies, adjustable………
•
•
•
·
P
·
• •
•
best kind.
Duroline pipe.
elbow angles..
elbows..
external shoulders
female and male threads.
•
883-926
FITTING…….
Pipe fitting(s), alleged nipple cutting . .912
assembling..
..920
918
.893
.902
..889
.906
.909
..908
.906
.919
..894
894
.905
902
887
.890
.910
917
..901
•
·
·
•
• ··
•
•
.619
.632
630, 631
.629
627
659, 660
.617
.627
663, 665
•
•
757
437
.94
•
997
81
.166
352
.76
..76
1002
150
..79
.916
126, 205
Pipe fitting (s)-continued
inside burrs...
joint compound.
lock nut..
"make up"
making up joint.
malleable fittings, dimensions.
nipple holder.
nipples..
pipe.
•
reamer.
reducers.
tees...
bending vise
bends, table.
cutters.
drilling jack, ill.
fitting.
joints.
·
• •
•
• •
•
properties of
tap and reamer, ills..
three grades..
vise..
• •
piping diagram steamer
“Stornoway” I ..
•••
•
·
· •
...
•
thread(s), Briggs' standard.
length of.
unions..
wrenches..
Pipe taps, drill sizes
Piping, boiler and engine.
preventing vibration..
Pitch..
fitting.
Pitting.
•
• •
•
· D
Pre-admission.
Points on hand firing.
Porcupine boiler, ills..
Port, length.
opening..
Position, crank, ill.
Positive injectors.
Potential energy.
Pot oil burners.
• •
•
·
·
•
absolute..
atmospheric.
barometer table...
Power house construction.
Power pump, crank end.
drives..
list of parts.
water end...
Precaution with blow off valve.
Pressure.
from barometer reading.
gauge..
sprayer oil burner, ills.
Primary, air supply.
feed water heaters.
Priming...
• • •
•
·
•
• •
+
•
• •
·
•
•
• •
..905
..922
889
.892
..922
..926
.910
..888
.883
.918
..916
904, 907
..916
..903
..926
..885
914
..884
..903
295
157, 236
..824
334
1004
..318
122
..993
380, 1012, 1017
.1018
493
4
632
292
413
418
415
.414
339
5
•
►
.925
..907
.893
899
..886
..924
..891
..921
..914
..291
•
•
·
.6
.5
•
•
7
7
6
623
.548
433
135, 331
Priming-continued
valve...
Principles, basic.
PROPERTIES OF BOILER
MATERIALS.
brittle.
cold, short.
shut..
ductile...
fusible.
hardness.
..
..
homogeneous.
hot short..
·
melting points.
resilience..
··
specific gravity.
strength.
tenacity.
weldable.
•••
•
••
►
•
• •
Properties of, circles.
saturated steam..
•
exhauster. .
feeder drive..
"blue flame”…………
bowl, and impact mills
burner.
classifier...
duplex burner.
essentials of.
•
hot air control.
impact, and attrition.
mill..
mill, details.
rotary burner.
shadow wall.
Radial stays
Radiation.
• ·
mill..
points on combustion.
pulverizers..
attrition.
•
••
•
..
• D
+
super-heated steam.
Proportioning oil burner.
PULVERIZED COAL SYSTEMS. 587-612
air swept tube mill..
automatic control.
· •
• • •
•
►
turbulence, how obtained
type R burner.
vortex burner
water walls..
Pumps...
·
• •
·
•
• ·
·
Q
Quadruple riveted joint..
R
•
•
•
.
•
141-144
.141
141
142
.142
.142
142
.142
142
142
143
143
.143
142
·
•
•
•
·
•
•
•
.144
.358
47-51
•
54, 55
631
..600
.607
588
.597
.603
593
608
589
594
598
612
.601
595
596
590
588
591
•
420
1
•
+
•
•
.591
603, 609
..611
..605
.604
.602
.588
277
• ·
231
172
..68
Range of vacuums, condensing.
Real cut off..
Regelation..
Release.
position, ill.
Remarkable characteristics of water. 19
Resilience..
Re-tubing.
143, 151
.352
..898
896
..104
..
..
•
..
Return bends, malleable, table.
·· •
··
•
various..
Reversed circulation.
REVERSING VALVE GEARS..1069-1094
alleged Stevenson link motion.
Bremme.
Hackworth.
essential parts.
moving picture.
Joy....
link motion.
• •
loose eccentric.
Marshall..
methods.
radial..
various..
Walschaert's.
Riding cut off.
equalizing the lead.
suspension..
discharge.
in general.
• •
•
..
• •
• •
O • • •
•
• •
•
how to calculate.
·
C
virtual travel, ills..
Ringelmann, chart.
smoke scale..
Riveted joint, efficiency.
element of...
•
•
•
major...
noisy operation.
packing...
•
•
equation..
essential parts.
example..
lever....
outside spring.
pop...
·
points in designing.
strength of...
Riveted joints...
Riveted screw stay, ill..
Rivets, shearing strength of.
Rotary Pump Troubles..
•
SAFETY VALVES..
Code States.
dead weight.
def....
•
•
.
-
•
•
+
• ·
•
•
•
•
S
•
• •
•
•
• •
•
717
1006, 1007
..21
1010
1009
•
•
•
•
·
..1073
1089, 1090
*
..1082
..1083
1084, 1085
1091, 1094
1071, 1074
..1077
1079
1069, 1072
1086, 1087
..1069
.1081-1094
1082
.1093
..1050
1061
..93
.92
159, 221
..222
•
•
•
..160
.220
163
221
423
.423
424
424
427
426
•
222
221
•
525-546
..527
..527
..525
542
527
544
527
.535
530, 531
•
Safety Valves-continued
application...
object of...
operation.
ring..
precaution..
principle of.
seat..
spring resistance.
types..
•
•
•
•
•
Safe working pressure.
Salinometer, scale markings.
Saturated steam.
Saw dust.
firing..
Scale, Fahrenheit.
getting rid of..
Scoop, condenser
•
·
O ·
•
• •
• •
• ·
scum.
Scotch boiler.
Screw stays, why break.
Secondary, air supply.
feed water heaters.
Sectional, boilers.
· •
header, ill....
Semi-dual bank condenser, ill..
Semi-flash generator.
Sensible heat.
··
tap..
stay, rod, ill.
tube.
• •
•
crow foot stay...
data on name plate.
diagonal stay..
double shear, adv..
drilled stay, ill..
efficiency of joint.
CONSTRUCTION.
Separators.
Shallow well pumps.
Shavings firing..
Shear....
Shearing strength of rivets
Sheets..
SHELL BOILER
•
·
•
·
..
•
• ·
•
flat surfaces..
Gusset stay.
lap and butt joints.
lap joint, cover plate.
objection..
ligament.
locomotive.
palm stay.
pitch..
plates, how tapped..
riveted, joint.
screw stay, ill..
sheets..
socket stay, ill.
stay bolt.
•
. •
•
•
·
• •
·
▸
•
·
• · •
•
• →
•
• •
•
•
•
•
•
•
1
•
•
•
•
+
•
..538
529
539
.534
531
526
217
.775
33
77
•
•
•
..336
.694
.336
120
164
.548
433
114, 198
199
O
.705
. 126
2, 36
285, 286
•
•
•
..428
316, 323
.152
221
.155
•
•
+
.155-180
169
178
.167
158
163
159
•
.316
.8
·
533
532
536
•
•
..161
166, 169
156
157
.156
160
.155
166
157
.161
.159
163
.155
.166
161, 178
162, 163
166, 167
167
·
•
•
Shell Boiler Construction-continued
stays...
spacing.
strength of joint.
submerged tubes.
through stay, ill. .
SHELL BOILER OPENINGS..
how classified...
major.
manholes..
minor..
··
•
• •
horizontal pump.
valve, gears..
K
SLIDE VALVE.
Short stroking, pump..
Simplex, double deck plate pump
piston steam valve.
separate aux. valve.
valves combined..
Single and divided flow
condensers, ills..
Single, and double shear
deck spray pond.
riveted lap joint.
shear...
tube condenser, ills..
water tube..
↓ Q
Allen valve..
angular advance.
apparent cut off.
balanced..
•••
•
defects, ill..
def...
distribution.
edge of valve
exhaust, lead
port....
• • •
• •
Bilgram diagram, ill..
Allen valve..
clearance..
compression, ill.
loss due to.
constant lead.
cut off, real..
cylinder, secitonal view, ill.
D valve...
•
•
• •
•
•
•
• •
•
• *
•
· •
•
•
extreme position, ills..
inside, admission.
lap..
lap, ill..
lead, constant.
exhaust..
object of.
negative position, ill..
position, ill.
unqualified.
variable..
· •
* •
length, of ports.
of seat, ills....
line and line position.
• ·
•
• •
• •
•
D
*
•
•
·
•
•
161
.169
160
177
166, 167
179-184
179
179
·
•
•
•
.180
.179
.416
372
..396
385, 389
391
• ·
.701
158
.750
..222
150
.694
.114
.989-1024
1015, 1017
.1032
1006
..996
.1019
.1022
.1008
1010, 1011
.1015
.386
.389
.1003
1006, 1007
..990
..989
1020-1024
•
..989
..989
.992
.1003
..994
1013
1006
..998
..997
.1003
1003
1001
.1001
1000
1002
.1003
.993
.994
1000
Slide Valve—continued
linear advance, ill...
negative, inside lap.
lap, ill……….
neutral position.
outside lap.
viston....
Smoke..
port, and passage, dif..
opening, ill..
ports, ill.....
pre-admission, object.
valve position, ill..
pre-release, function.
release position, ill.
steam, chest, ill..
lap...
terminal position.
travel of valve..
valve, motion, table.
on seat, ill...
seat..
variable lead, ills.
width of ports..
...
+
how classified.
•
•
..
··
rod, ill..
spacing.
tube..
•
Special boilers.
Specific gravity.
Specific heat..
tables.
various substances.
Specimen..
Spheroidal state.
··
indication.
Socket stay, ill.
Soft patch.
Soot, accumulation of
• •
•
•
•
•
•
•
·
....
U
• •
•
•
…….
• •
•
•
•
• •
• · •
•
• •
Spindle stay bolt tap, ill.
Sprayer oil burners, operation.
Spraying, action of..
•
Spray nozzle..
Spray pond, double deck, ills.
effect of weather.
louvre fence..
single deck.
Standard atmosphere.
Starting the fire..
• •
• • •
+
broken, how detected..
tap..
threads.
Stay(s)...
crow foot.
diagonal.
fastening methods.
Gusset.
•
•
•
•
•
• •
·
•
• •
•
"Stationary” working pressure….
Stay bolts...
•
•
•
•
..995
1004
1004
.1010
1009, 1010
991
•
+
.993
.989
1002, 1003
..993
•
..1016
..999
..998
.997
•
•
•
..992
1012
..998
.996
..997
1009
1014
1018
•
89, 90
.92
..90
..166
352, 353
.333
.209
.22, 143
69, 170
72
71
145
.107
165
.627
.751
.752
.751
.754
753
.750
11,18
299
..35
161, 238
.178
·
•
·
.162
.163
.242
.169
.167
.176
..169
166, 167
.169
167, 170
•
•
• •
STEAM....
boiling point.
bubbles, formation of.
characteristics..
chest, ill..
cocks, various.
condensate...
condensation.
••••
def...
distribution.
dome..
dry..
edge of valve ill.
•
• •
•
sensible heat.
so-called.
space....
·
• •
• •
gaseous..
gauge.
heat required.
internal latent heat.
kinds of..
loop...
pressures.
process of boiling.
saturated..
•
• • •
•
engineers knowledge of.
external latent heat, alleged and real;
see author's note..
factor of evaporation.
formation of………….
from and at 212° Fahr.
•
•
· ·
superheated…..
saving.
tables, saturated.
how to use
superheated.
the medium.
total heat..
unqualified..
variation of boiling point.
wet....
white cloud.
·
basic principles.
Boyle's law...
brasses...
working pressure..
STEAM ENGINE(S)
angularity of rod..
Babbitt metal..
·
•
+
connecting rod.
angularity of.
various, ills..
cross head(s), ills
various, ills.
def...
diagram factors.
drop....
essential elements.
expansion diagram.
fly wheel...
•
··
•
• • •
•
•
·
• ·
•
•
·
•
·
· •
•
*
..99
31
..992
255-265
31-58
.44
.31
.835, 989
….184
.33
.993
.33
•
+
•
266, 268
..36
.38
.46
289
.34
41
33
.36
.9
134
52, 53
.52
47-51
.46
54-55
•
·
43
43
[
39
58
.36
39
33
•
32
41
32
.45
33
31
.35
945-976
.970
..966
..945
.952
..966
965, 968
..970
967, 968
..963
.965
..945
958, 959
..952
.945
.955
..975
Steam Engine(s)—continued
"gudeon".
...
Graham two cylinder oscillating..948
hyperbolic logarithm.
horizontal, ill.
initial pressure...
lines, indicator diagram.
main bearing..
mean effective pressure.
names of parts...
number of expansions.
operation...
piston, rings, ills..
rods...
running over-under, ills
shaft.
split belt wheel.
atmospheric.
def...
automatic, air vent.
control..
damper.
+ •
branch main…..
circuit with loop, ill.
concealed radiation.
distribution..
dry return.
exhaust...
heating, elements
...
..947
..952
..949
960-961
..962
..964
stuffing box...
971
..974
959, 960
.953
terminal pressure.
turning force..
..969
valve setting, finding dead center..1096
web crank arm..
STEAM HEATING SYSTEMS..815-846
..971
834, 835
833
.832
845
833
.817
830
.841
• •
vacuum.
def...
•
Surface arrangement.
· • •
•
·
• •
Hi-jet..
how classed.
indirect...
low pressure.
def...
one pipe, circuit, ill.
divided circuit.
overhead system.
relief, ill....
piping methods, ill..
return, bend, pitch, ills..
pipes...
hammer, ill...
pockets
• ►
riser, connections, ills..
main connection, ill.
two pipe.
wet return.
wiring diagram.
•
·
vapor, def.
variator..
water, backing up, ill.
• +
•
•
· ·
• •
• ·
•
•
• •
+
.956
946, 947
..952
..954
972, 973
955, 959
•
•
·
•
.969
·
..835
.817
838
.831
.808
.843
.815
846
817
833
.828
..827
824
...816
821, 822
824
.817
.819
..820
.832
836
•
·
•
.833
833
840
825
823
.823
618, 817
844
STEAM, INSTANT 126A-126F
motorized valve....
non-photo-electric control.
non-recirculating flash boiler.
photo-electric control..
recirculating flash boiler..
STEAM JET AIR EJECTORS
application......
drain loop.
essential parts.
how classed..
•
multiple, ills..
multi-stage ills..
operation....
shutting down.
single stage, ills..
starting up.
three stage..
two stage.
STEAM TRAPS.
"blast".
compound.
def...
duty..
free floating valve..
•
impulse...
installation..
aligning..
bearings.
•
•
• • ·
· · · •
·
..
..
• •
inverted bucket…….
mysterious trouble.
return..
specific gravity.
steam loss.
thermal..
troubles.
various....
··
••
+
•
upright bucket..
STEAM TURBINES.
·
• ·
•
•
bearing temperatures.
carbon rings..
casings..
classification.
compound.
multi-stage.
•
•
•
•
• •
•
•
•
so-called impulse.
condition for rotation..
4
•
►
*
DH, ball bearing type.
end view.
side view..
dual...
equal pressure.
erection..
essential parts.
foundation.
governor(s).
lubrication.
•
•
•
•
•
•
·
·
·
• • •
-
• • ·
•
• •
..126D
126 E
126 F
126H
126 B
731-746
.732
.744
731
.732
741
.739
731, 734
.740
733
.735
.734
.734
509-524
•
•
•
•
•
•
·
•
513
516
512
.519
524
511,517
•
+
•
+
1163-1220
.1200
1211, 1212
1220
1211
+
•
•
•
• •
519
..520
..509
..509
1176
1165
1181, 1190
1188, 1189
1183
1171
1214
1209
1207
.1182
1173
1197
1163
1200
1177
1178
•
•
•
.514
523
518
•
.521
.510
.515
Steam Turbines—continued
how mounted………..
impulse, and reaction.
def....
inlet line..
kinetic energy
maintenance.
miscellaneous.
nozzles.
oil, cooling.
kind of.
operation..
after starting.
before starting.
lubrication.
shutting down.
overspeed governor.
pipe connections.
•
principle..
reaction..
• · • • •
•
principle of.
•
··
• •
•
•
• • •
•
•
►
..
• •
Scotch mill..
shaft packing..
single stage, con. detail.
··
·
• •
so called impulse.
speed, adjustment.
governors....
troubles...
unequal pressure..
vanes..
•
•
calculation…..
efficiency of.
element.
· • ·
• •
• •
... •
Stop valve.
Strain..
Straw.
firing..
Stress.
bending.
STRENGTH OF BOILERS.
··
••
·
•
•
various types of...
ligaments..
areas of heads to be stayed..
bursting pressure..
butt and double strap joint.
circumferential joints..
diagonal spacing.
efficiency of joint.
factor of safety.
flat surfaces.
lap and butt joint, dif.
P ·
lap joint, objection to..
..
• •
principle, ills...
quadruple riveted joint.
riveted joint(s).
• •
•
•
•
•
•
• •
rules...
safe working pressure.
shearing strength of rivets.
single riveted lap joint, ill..
spacing of tubes...
1
•
•
▸
•
•
•
•
.1209
.1197
1174, 1189
.1212
1208
1204
.1206
.1206
.1208
1206
1205
.1204
1164
1169, 1189
1192
1170
1179
• • •
•
•
•
•
•
•
·
•
.1180
1173, 1174
1179, 1216
•
.1203
1217, 1218
1189
1175
.247
152
.77
.315
.162
.145
.211-244
.239
215, 217
.228
.239
1200
1167
1167
1202
1194
•
·
U
·
·
237
.214
.217
238
221
.221
.221
237
212
•
•
•
•
..231
220, 223
.222, 223
..221
223
..215
.217
221
..222
.236
Strength of Boilers-continued
stay bolts...
strength of shell, rule..
thickness of shell.
triple riveted joint.
Submerged tube boiler
Super-chargers..
Superheated steam.
Super-heating, saving.
Surface, liberating.
Surface condenser(s).
and pumps, ills...
author's box...
counter flow, ills.
cross flow, ills..
def....
double, flow, ills.
tube, ills...
tube....
starting.
troubles..
tubes..
•
• •
evaporator. .
gauging cooling water.
·
"
•
•
large, ills...
leaky tubes..
one and two pass, ills..
operation.
...
•
•
•
..
·
...
• •
•
•
scoop...
semi-dual bank, ills..
single, and divided flow, ills..
·
•
test...
Tension.
TESTS OF BOILER
•
•
··
·
MATERIALS….
•
U
•
•
•
•
·
two pass high vacuum, ills..
water, and steam circuit..
works...
Swinging eccentric, ills..
•
T
•
•
•
+
Tail pipe, barometric condenser.
Tan bark..
firing..
Temperature.
how measured.
Tenacity..
Tensile, strength.
•
•
•
bending stress.
coef. of elasticity.
deformation.
factor of safety.
force......
load...
member...
modulus, of elasticity
of rupture.
permanent set.
.
·
•
•
•
•
•
•
•
► •
•
• ·
• • ·
·
•
·
238, 239
..213
.219
.229
115, 177
1361
33, 52
..52
.134
..689
..696
.693
.704
..703
..689
..707
..697
..720
.711
710
•
•
•
•
..707
..700
..704
..694
.705
..701
..694
..708
..703
..702
·
•
..698
..702
.697
1042
689
.77
317
2, 60
145-154
145
148
147
147
147
•
..60
.143
153
146
.153
•
·
•
•
•
148
.148
148
149
.150
►
·
Test of Boiler Materials—continued
resilience.
shear.
specimen.
standard..
strain..
stress.
tensile strength.
tension..
tortion.
..
·· •
..
transverse test.
ultimate strength.
• •
• •
►
amount of fuel burned.
"boiler horse power"
duty..
foaming.
gas passage.
grate....
•
·
·
·
scale..
Three stages.
of matter..
of water...
tube boiler.
Throw.
Tortion..
quality of steam.
shell...
..
function of.
heating surface ratio.
shape of...
tube...
Thermometer.
steam space.
water, evaporator.
heating surface.
basis of measurement
liberating surface.
priming..
•
yield point..
THE NATURE OF BOILERS……. 127-138
air space...
•• •
•
•
·
·
• • •
cutting..
Tube(s).
for condensers.
stopper, ills..
tools, ills..
•
·
Total combustible.
Transfer of heat.
Transverse test.
Travel....
Traveling grate.
riveted joint..
Troubles, oil burners,
Tube condenser.
•
• +
•
•
•
• •
·
• •
•
•
•
U
Ultimate strength..
Unit of heat....
· •
• •
- •
·
•
•
•
•
•
·
151
..152
145
.146
..152
.152
153
.153
151
.149
.153
154
·
146,
·
•
•
133
131
.129
.127
.136
132
127
.130
128, 131
130
127
129
134
.135
137
.136
..134
•
•
•
•
•
•
..115
1031
151
73
3, 68
149
1020
574
+
. •
132
136
.8
.8
40
1
.17
•
•
..229
663, 665
..694
.350
113
702
348
349
•
•
倡
​..153
.59
Vacuum.
•
breaker..
def...
how lost.
how measured.
pump, so-called.
Valve, motion, table
seat...
VALVE GEAR.
· •
• • D
•
angular advance.
def...
direct...
eccentric.
strap.
eccentricity.
indirect..
motion.
·
...
• • ·
valve stem..
yoke..
• •
• •
*
linear advance.
outside eccentric rod.
principal classes of.
simple..
throw..
· •
...
•
VALVE SETTING..
angular advance
duplex pump..
•
•
··
•
•
•
V
•
•
+
the lead...
finding, angular advance.
dead center.
length of valve stem.
·
•
emergency rule..
equalizing, riding travel, ills…….
•
"
• •
inside admission..
link motion..
location of ports, ills.
main, and riding valve, ills.
valve....
•
•
Meyer gear, ill..
pump gears.
..
riding, cut off gear, ills..
• •
eccentric.
valve.
Valve stem.
Vaporization.
VARIABLE CUT OFF.
basic principle.
characteristics.
features...
Gonzenbach valve, ills.
independent.
methods..
•
•
·
•
+
Meyer gear.
offset swinging eccentric.
link motion
re-admission, how avoided.
riding..
•
•
•
•
•
•
•
•
•
+
•
.6
.686
.671
.704
..676
.9, 29, 676
1018
..989
1025-1034
▸
1031
.1025
.1032
.1031
.1029
1031
1032
.1033
.1032
1034
1034
1026
.1031
.1028
1025, 1027
1095-1130
.1105
1024, 1125
1111
..1115
1099, 1100
..1098
1096, 1097
..1098
.1107
1119-1122
+
•
·
·
•
•
.1118
1117
1123
1113
1118
1118
.1028
...36
D
•
· •
•
·
1109
1112
.1035-1068
1036
1064
.1060
.1048
.1049
.1035
1060, 1065
·
..1044
..1064
..1065
.1052
Variable Cut Off—continued
variable lap..
shifting eccentric.
slide valve defects..
swinging eccentric, ills..
virtual travel, ills…..
with variable travel.
Variable lead, ills...
Various eibows..
Venturi oil burners, ill. . .
• •
Vertical, boiler, through tube
horizontal shell boiler.
tubular boilers.
Volatile matter..
WATER..
column.
cooled furnaces.
contraction of.
••••
• • •
air, and water.
boiling point..
circulation in boilers.
•
· •
·
Almy, ills...
bent tubes..
•
•
·
·
• • ·
• •
def....
expansion of.
freezing and boiling points.
fusion...
gauge..
indication.
head, two kinds of.
ice, weight of.
latent heat...
least density of..
maximum density of.
melting point.....
most remarkable characteristic.
•
W
··
per U. S. gallon.
regelation.....
removal pump, ills.
specific gravity of ice.
thermal circulation.
three states..
treatment..
weight, of.
•
• ❤
..
D
work of fusion..
WATER TUBE BOILER
CONSTRUCTION…….
circular flues.
curved tubes.
def....
directed flow, ills..
door, construction.
sizes.
►
•
•
..1060
1039, 1040
1046
.1042
.1061
1068
1002
895
632
175
112
174
.73
* ·
•
•
• •
· •
•
·
•
• •
· •
17-30
.29
.23
.25
•
*
•
• •
•
17
19
.18
.20
.263
28, 302
•
· •
•
.264
.793
.19
•
· · •
•
•
►
• •
· · • •
•
•
•
•
.28
•
.18
.20
23
• •
·
.23
21
.467
17, 26
.26
690
. 22
26
17
•
19.
21
•
.185-210
..208
...199
..243
198, 201
.185
.194
.189
189
.23
Water Tube Boiler Construction
down flow...
fire door opening.
flash....
flat surfaces.
"freaks".
• ·
Graham sectional series boiler, ills....204
Graham special...
hand hole plates, ills..
..
segments.
special.
stay(s)..
tubes...
•
inclination of tubes, ills..
ligaments..
longitudinal drum, ills.
non-sectional..
nozzles...
over discharge, ills..
parts, ills
pipe boiler..
porcupine.
sectional..
·
·
•
..
•
• •
•
and non-sectional, ills..
header, ill...
• • •
• •
• •
•
...
•
under discharge, ills..
up flow...
Yield point.....
•
•
various bent tubes, ills..
water grate.
Weldable....
Wet, air pump, calculation.
steam.
White cloud.
Wire drawing..
Wood, heating value of
Work..
of fusion..
Working pressure.
•
•
• •
•
Y
straight and curved tubes.
strength of boilers, riveted joints. 225-234
transverse drum..
tube, and pipes, dif., ills
arrangements..
holding power.
in parallel, ills..
in series parallel, ills..
Z
·
· •
•
•
Zero, absolute..
clearance air pump, author's.
Zinc, action of..
4
·
+
•
*
cont
124, 209
.189
.209
238
210
•
204
200
193
235
.203
195, 198
..188
.195
196
.207
..202
197, 198
.186
.199
.240
209
242
.242
.200
•
•
# ·
•
··
•
•
•
•
•
..203
. 191
.187
.189
192
•
·
192
.195
193, 209
.190
207, 210
.144
.727
33
31
993
76, 77
4
·
• •
•
•
+
23
217
+ ·
..154
8
..692
..335
1:
"",
Basic Principles
1
CHAPTER 1
Basic Principles
Define the term basic principles.
Ans. The fundamental laws which govern the behavior of
substances when acted upon by any external agency
agencies.
or
Of what value is this in taking an examination for
engineers' license?
Ans. With a knowledge of these fundamental laws, the appli-
cant is better equipped to reason out the problems and answer
the questions.
Why are engineers required to take an examination
before obtaining a license?
Ans. Because a boiler is a dangerous thing, especially in the
hands of an ignorant person.
What is a molecule?
Ans. The smallest particle in which a substance can exist in
the free or uncombined state.
What are the three states of matter?
Ans. 1, Solid; 2, liquid, and 3, gas.
2
Basic Principles
How are the three states distinguished with respect to
the molecules?
Ans. By the character of their motion.
How do the molecules move in a solid?
Ans. Back and forth like tiny pendulums.
How do they move in a liquid?
Ans. They wander all around without any definite path.
How do they move in a gas?
Ans. In straight lines.
What is heat?
Ans. A form of energy known by its effects.
How are these effects indicated?
Ans. Through the touch and feeling as well as by the expan-
sion, fusion, combustion or evaporation of the matter upon
which it acts.
What is sensible heat?
Ans. That heat which produces a rise of temperature as dis-
tinguished from latent heat, which produces a change of state.
What is latent heat?
Ans. The quantity of heat required to change the state or
condition under which a substance exists without changing its
temperature.
What is temperature?
Ans. That which indicates how hot or cold a substance is:
a measure of sensible heat.
Basic Principles
3
What is specific heat?
Ans. The ratio of the quantity of heat required to raise the
temperature of a given weight of any substance one degree
Fahr. to the quantity of heat required to raise the temperature
of the same weight of water from 62° to 63° Fahr.
The capacity of any substance for receiving heat as compared with
another which is taken as a standard, this being generally water. Thus,
the same quantity of heat which will raise one pound of water 1° Fahr.
will raise about 44 pounds of cast iron 1° Fahr. so, the specific heat
of water being taken as 1.000 that of cast iron is 0.241.
When does a transfer of heat take place?
Ans. When bodies of unequal temperatures are placed near
each other, heat leaves the hot body and is absorbed by the
cold body until the temperature of each is equal.
How fast does the transfer take place?
Ans. The rate by which heat is absorbed by the colder body
is proportional to the difference of temperatures of the two
bodies.
How does a transfer of heat take place?
Ans. By radiation, conduction or convection.
What is the relation between heat and work?
Ans. Heat develops mechanical force and motion, hence it
is convertible into mechanical work.
How is heat measured?
Ans. By a standard unit called the British thermal unit
abbreviated B.t.u.
What is the (mean) B.t.u.?
4
Basic Principles
1
Ans. 180 part of the heat required to raise the temperature
of one pound of water from 32° to 212° Fahr.
What is work?
Ans. The overcoming of resistance through a certain distance
by the expenditure of energy.
How is work measured?
Ans. By a standard unit called the foot pound.
What is a foot pound?
Ans. The amount of work done in raising one pound one
foot, or in overcoming a pressure of one pound through a dis-
tance of one foot.
What is the relation between the unit of heat and the
unit of work?
Ans. 1 B.t.u.=777.52 foot pounds.
What is energy?
Ans. Stored work, that is, the ability to do work.
Name two kinds of energy.
Ans. Potential energy and kinetic energy.
What is potential energy?
Ans. Energy due to position.
What is kinetic energy?
Ans. Energy possessed by a moving body due to its momen-
tum.
What is power?
Ans. The rate at which work is done.
Pasic Principles
5
ел
What is one horse power?
Ans. 33,000 foot pounds per minute.
How is pressure usually measured?
Ans. As pounds per square inch.
What is pressure?
Ans. As defined by Rankine: A force of the nature of a
thrust, distributed over a surface.
What is atmospheric pressure?
Ans. The force exerted by the weight of the atmosphere on
every point with which it is in contact.
How great is the atmospheric pressure?
Ans. It is generally taken at 14.7 lbs. per sq. in. at sea level.
Why do we not feel this pressure?
Ans. Because air presses the body both externally and inter-
nally so that the pressures in different directions balance.
How is most of the atmospheric pressure got rid of?
Ans. By the use of a condenser.
What effect has atmospheric pressure on steam engine
operation?
Ans. It acts as a back pressure on the engine piston and so
reduces the power.
How is the pressure of the atmosphere measured?
Ans. By an instrument called a harometer.
6
Basic Principles
How is a barometer constructed?
Ans. Essentially it consists of a glass tube 33 to 34 ins. long,
sealed at one end, filled with mercury and inverted in an open
cup of mercury.
How does it measure the pressure of the atmosphere?
Ans. By the height of the column of mercury in the tube
above the level of the mercury in the cup. The reading gives
the pressure in terms of "inches of mercury."
What is a vacuum?
Ans. A space devoid of matter; a space in which the pressure
is zero.
What is the difference between gauge pressure and abso-
lute pressure?
Ans. Gauge pressure is pressure measured above atmospheric
pressure; absolute pressure is pressure measured above zero,
that is, = gauge pressure+pressure of the atmosphere.
What are the applications of these pressures?
Ans. Gauge pressure is used for measuring the pressure in a
boiler, automobile tire, etc. Absolute pressure is used in all
calculations relating to the expansion of steam.
How is absolute pressure expressed in gauge pressure?
Ans. By subtracting 14.7.
How are pressures below that of the atmosphere usually
expressed?
Ans. As lbs. per sq. in. absolute in making calculations or
the equivalent in "inches of mercury" in practice.
Basic Principles
7
What is the meaning of the term "referred to a 30 inch
barometer"?
Ans. It means that the variable pressure of the atmosphere
is in value such that it will cause the mercurv in the barometer
to rise 30 inches.
What can be said about such expressions as a 24 inch
vacuum?
Ans. Ridiculous in that it is not a vacuum strictly speaking,
but only a partial vacuum, yet nothing can be done about it.
How is the pressure in lbs. per sq. in. obtained from the
barometer reading?
Ans. RULE: Barometer reading in inches X.49116-pressure
per sq. in.
Various readings are given in the following table:
Pressure of the atmosphere per square inch for various readings of
the barometer:
Rule.-Barometer in inches of mercuryX.49116 lbs. per sq. in.

Barometer
(ins. of mercury)
28.00
28.25
28.50
28.75
29.00
29.25
29.50
29.75
Pressure
per sq. ins., lbs.
13.75
13.88
14.00
14.12
14.24
14.37
14.49
14.61
Barometer
(ins. of mercury)
29.921
30.00
30.25
30.50
30.75
31.00
Pressure
per sq. ins., lbs.
14.696
14.74
14.86
14.98
15.10
15.23
The above table is based on the standard atmosphere, (which by defin-
ition=29.921 ins. of mercury=14.696 lbs. per sq. in., that is I in. of
mercury=14.696÷29.921.49116 lbs. per sq. in.
8
Basic Principles
L
What is a thermometer?
Ans. A device to measure temperature.
Of what does it consist?
Ans. It consists of a glass tube terminating in a bulb which
is charged usually with mercury.
How does it measure the temperature?
Ans. By the contraction or expansion of the liquid with tem-
perature changes, causing the liquid to rise or recede in the tube.
What is provided to determine the degree of heat?
Ans. An arbitrary scale divided into "degrees."
What is the Fahrenheit scale?
Ans. The scale generally used in English speaking countries.
On this scale the freezing point is 32° and the boiling point 212°.
What is the absolute zero?
Ans. A point which has been determined on the thermometer
scale (by theoretical considerations) beyond which a further
decrease in temperature is inconceivable.
It is that temperature at which the volume of a gas would have
become zero or it would have lost all the molecular vibration which
manifests itself as heat.
What is the absolute zero temperature?
Ans. -459.6° Fahr.
What is steam?
Ans. The vapor of water, being a colorless expansive invisible
fluid.
Basic Principles
9
What is the white cloud seen issuing from an exhaust
pipe and called steam by greenhorns?
Ans. This is not steam, but in reality a fog of minute liquid
particles produced by condensation of steam.
Under what conditions does steam exist?
Ans. When there is the proper relation between the tem-
perature of the water and the external pressure.
What is condensation?
Ans. The reduction in bulk of any substance accompanied
by increase in density.
Describe the condensation of steam.
Ans. When the temperature of steam becomes less than that
corresponding to its pressure, condensation takes place, that is,
it ceases to exist as steam and becomes water.
When steam condenses what is the liquid called?
Ans. The condensate.
What happens during the condensation of steam?
Ans. Air which was originally mechanically mixed in the
water is liberated.
What must be provided for condensers to maintain a
vacuum?
Ans. The liberated air coming in with the condensate, must
be removed from the condenser.
How is this done?
Ans. By an air pump, ignorantly called a vacuum pump.
10
Basic Principles
1
I
L
What is the law of expansion and contraction?
Ans. Practically all substances expand with increase in tem-
perature and contract with decrease of temperature.
What is the difference between linear and volumetric
expansion?
Ans. Linear expansion is the expansion of solid bodies in a
longitudinal direction; the expansion in volume is called volu-
metric expansion.
Define friction.
Ans. It is that force which acts between two bodies at their
surface of contact so as to resist their sliding on each other.
Define efficiency.
Ans. It is the ratio of the useful work performed by a prime
mover to the energy expended. In other words: The output
divided by the input.
Air
11
CHAPTER 2
Air
By definition: Air is a gas consisting of a mechanical mixture
of 23.2 per cent of oxygen (by weight), 75.5 per cent nitrogen
and 1.3 per cent argon. Carbonic acid is present to the extent
of about .03 or .04 per cent of the volume. Obscure constituents
are: .01 per cent kryplon with small amounts of several gases.
What should an engineer know about air?
Ans. Its presence in boilers tends to oxidize the metal; air
in condensers destroys the vacuum necessitating the use of an
air pump. It is a problem to get rid of air in heating systems.
What is the standard atmosphere?
Ans. A pressure of 29.921 ins. of mercury which is equal to
14.696 lbs. per sq. in.
Does the pressure of the atmosphere always remain con-
stant in any one place?
Ans. No.
How does it vary?
Ans. It continually varies as indicated by the reading of the
barometer, depending upon weather conditions.
12
Air
How does the pressure of the atmosphere vary with the
elevation?
Ans. It decreases approximately one half pound for every
1,000 feet of ascent.
Give a familiar illustration of decreasing air pressure.
Ans. In driving an automobile up a high mountain there is
a gradual loss of power during the ascent because less air is
admitted and the charge becomes too rich.

INS.
30
28.55
27.09
25.78
22.11
19.92-
0.
SEA
LEVEL
4 MILE
2 MILE
MILE
1
MILE
12 MILE
2 MILES
LBS.
14.75-
14.02
3.33
42.66
-12.02
-10.88
9.8
SEA LEVEL 4 MILE 1/2 MILE 1/4 MILE
IMILE 1/2 MILES 2 MILES
Fig. 1.-Mercurial barometer illustrating the relation between "inches of mer-
cury" absolute pressure and boiling point.
Of what possible use is this fact to an engineer taking
an examination?
Ans. Since the atmospheric pressure decreases about one half
pound per 1,000 ft. elevation, engine efficiency and capacity
are affected accordingly.
How is it affected?
Ans. The efficiencies of simple and compound non-condensing
engines vary directly with the altitude. With condensing engines
the variation is in the other direction, but according to Marks
is so slight as to be negligible.
Air
13
Does air have weight?
Ans. Yes.
What is the volume of one pound of air at 32° Fahr. and
standard atmospheric pressure?
Ans. 12.39 cu. ft.
What is the weight of one cu. ft. of air at 32° Fahr. and
standard atmospheric pressure?
Ans. 0.08071 lb.
Mention an application of this unit.
Ans. It is used in some calculations for compressed air.
What is free air?
Ans. Air at normal atmospheric conditions.
How is this definition modified with respect to air com-
pressors?
Ans. It is stated as: Air at the atmospheric conditions at the
point where the compressor is installed.
What is normal air?
Ans. Air with 36 per cent relative humidity at 68° Fahr.
What is relative humidity?
Ans. The degree of saturation of the air with watery vapor.
What happens when air is compressed?
Ans. When the space occupied by a given volume of air is
changed, both its pressure and temperature are changed in
accordance with Boyle's and Charles' laws.
For compression and expansion of a gas see also Chapter on Steam.
14
Air
What is Boyle's law?
Ans. At constant temperature the absolute pressure of a gas
varies inversely as its volume.
What is Charles' law?
Ans. At constant pressure, the volume of a gas is proportional
to its absolute temperature.
What should be noted with respect to calculations in-
volving Charles' and Boyle's laws?
Ans. Absolute pressure and absolute temperature should be
taken.
C
ABSOLUTE
PRESSURE
GAUGE
B
ate |
080211 1111
1001 ADEL
VACUUM
GAUGE
14.696
(LBS. PER SQ. IN.)
B
A
ZERO

29.921 INS.
A
GAUGE
PRESSURE

ZERO
ZERO
Figs. 2 and 3.-Elementary diagrams illustrating difference between gauge
and absolute pressure.
What is the absolute zero?
Ans. As before stated, 459.6 degrees below 0° on the Fahren-
heit scale, written-459.6°.
What is the significance of the absolute zero?
Ans. Experiments have demonstrated that a gas expands
Air
15
when at the freezing point and under constant pressure about
1
491.6 of its volume for each increase of 1° Fahr. in temperature.
This tends to show that at some point about 491.6-32° or 459.6°
below zero on Fahrenheit scale, the volume of the gas would
have become zero or it would have lost all the molecular vibra-
tion which manifests itself as heat.
Volume and Weight of Air
(at atmospheric pressure for different temperatures)

Tempera-
ture,
Degrees
Fahr.
•
12
22
32
43
52
72
82
92
102
112
122
132
142
152
162
172
182
192
202
212
230
250
275
300
Volume of
I Pound
of Air in
Cubic
Feet
II.57
11.88
12.14
12.39
12.64
12.89
13.14
13.39
13.64
13.89
14.14
14.41
14.66
14.90
15.17
15.41
15.67
15.92
16.18
Weight
per Cubic
Foot.
Pounds
0.0864
0.0842
0.0824
0.0807
0.0791
0.0776
0.0761
0.0747
0.0733
0.0720
0.0707
0.0694
0.0682
0.0671
0.0659
0.0649
0.0638
0.0628
0.0618
16.42
о.обод
16.67 0.0600
16.92 0.0591
0.0575
17.39
17.89
0.0559
18.52 0.0540
19.16 0.0522
Temper
ature,
Degrees
Fahr.
325
350
375
400
450
500
600
700
800
goo
1000
1100
1200
1300
1400
1500
1600
1700
1800
2000
2200
2400
2600
2800
3000
Volume of
I Pound
of Air in
Cubic
Feet
19.76
20.41
29.96
21.69.
22.94
24.21
26.60
29:59
31.75
34.25
37.3!
39.37
41.84
44.44
46.95
49.51
52.08
54.64
57.14
62.11
67.11
72.46
76.92
82.64
87.72
Weight
per Cubic
Foot,
Pounds
0.0506
0.0490
0.0477
0.0461
0.0436
0.0413
0.0376
0.0338
0.0315
0.0292
0.0268
0.0254
b.0239
0.0225.
0.0213
0.0202
0.0192
0.0183
0.0175
0.0161
0.0149
0.0138
0.0130
0.0121
0.0114
16
Air
What is the lowest temperature yet obtained by anyone?
Ans. -430.6 Fahr. which is the freezing point of hydrogen.
Water
17
CHAPTER 3
Water
What is water?
Ans. A colorless transparent liquid being a compound com-
posed of hydrogen and oxygen in the proportion of 2 parts by
weight of hydrogen to 16 parts by weight of oxygen.
What is the chemical symbol for water?
Ans. H₂O.
What effect has temperature and pressure upon this
substance H₂O?
Ans. It may exist as: 1, a solid; 2, a liquid; or 3, a gas.
What is it called in these three states?
Ans. 1, Ice; 2, water; and 3, steam, as in fig. 1.
What is the weight of one cu. ft. of ice at 212° Fahr.?
Ans. 57.5 lbs.
What is the weight of one cu. ft. of water at 32° Fahr.?
Ans. 62.41 lbs.
18
Water
Why is the weight of ice less than that of water?
Ans. It is due to expansion on freezing. That is, there is less
than one cu. ft. of water per cu. ft. of ice.
What are the freezing and boiling points of water at
atmospheric pressure at sea level?
Ans. 32° and 212° Fahr. respectively when the barometer
reads 29.921 ins.
3RD. STATE
STEAM

Fig. 1.-Frozen radiator illustrating the three states.
What is the reading 29.921 ins.?
Ans. The standard atmosphere.
IST. STATE
ICE
2ND. STATE
WATER
What is the equivalent in pounds per square inch?
Ans. 14.696 lbs. per sq. in.
Water
19
What is the most remarkable characteristic of water?
Ans. At maximum density (39.1° Fahr.) water will expand
as heat is added and it will expand slightly as the temperature
falls from this point as shown in figs. 2 to 4.
29
What also besides hydrogen and oxygen is contained in
water and why is it a nuisance?

CU.INS.
SCALE
28
مر گزرج
Wi
27.7 INS.
32°
EXPANSION
WITH
FALL OF TEMPERATURE
27.68 INS.
39.1°
POINT OF
MAXIMUM DENSITY
28.88 INS.
KITTTTTTT
EXPANSION
212°
||T HIM IFT
OF TEMPERATURE
RISE
Figs. 2 to 4.-The most remarkable characteristic of water: expansion below and
above its temperature or "point of maximum density" 39.1° Fahr. Imagine
one pound of water at 39.1° Fahr. placed in a cylinder having a cross sectional
area of 1 sq. in. as in fig. 3. The water having a volume of 27.68 cu. ins. will
fill the cylinder to a height of 27.68 ins. If the liquid be cooled it will expand
and, at say, the freezing point 32° Fahr. will rise in the tube to a height of
27.7 ins. as in fig. 2 before freezing. Again, if the liquid in fig. 3 be heated,
it will also expand and rise in the tube, and at say the boiling point (for
atmospheric pressure 212° Fahr.) will occupy the tube to a height of 28.88
cu. ins. as in fig. 4.
20
Water
Ans. Water contains mechanically mixed with it about 5 per
cent of air by volume. For this reason air pumps are necessary
with condensers. Moreover the air attacks the boiler internally.
What is "fusion"?
Ans. A change of state of a substance from the solid form to
the liquid form.
What is the common word for fusion?
Ans. Melting.
Describe the fusion of ice
Ans. If heat be applied to the ice it will gradually melt, but
during the melting process the temperature will remain the
same.
Why?
Ans. It is due to the latent heat of fusion.
What is latent heat?
Ans. It is that quantity of heat which disappears or becomes
"concealed" in a body while producing some change in it other
than a rise of temperature, that is, the temperature remains
constant while the latent heat disappears.
How is latent heat measured?
Ans. By B.t.u.
What is the latent heat of fusion?
Ans. The amount of heat required to melt one pound of ice
at 32°.
In amount what is it?
Ans. 143.57 B.t.u.
Water
21
What name is given to the temperature at which fusion
takes place?
Ans. The melting point.
Upon what does the melting point depend?
Ans. Upon the pressure.
How does it vary with the pressure?
Ans. Ice melts at 32° Fahr. at standard atmospheric pressure
and freezes at the same temperature. At higher pressures the
melting point of ice, or the freezing point of water is lower,
being at the rate of .0133° Fahr. for each additional atmosphere
of pressure.
What is regelation?
Ans. Re-freezing or secondary freezing.
Give a familiar example of this phenomenon.
Ans. In making a snow ball if the snow be near the melting
point, the pressure of the hand is sufficient to squeeze it into
a compact partially solidified mass. When the snow is squeezed
between the hands, melting occurs at the points of greatest
pressure, and solidification follows as soon as the resulting
liquid is relieved of the pressure. See fig. 5.
What important change takes place during the melting
of ice?
Ans. It decreases in volume.
Why is the change of volume important?
Ans. Because precautions must be taken with apparatus in
which water is used, to prevent damage in case of freezing.
22
Water
Give a familiar example.
Ans. Water pipes burst when the temperature is a few de-
grees below 32°, although it requires a pressure of 14,000 lbs.
per sq. in. to burst some ordinary wrought pipe.
How much is the decrease in volume?
Ans. The relative volume of ice to water at 32° Fahr. is as
1.0855 to 1; that is, the space occupied by one pound of ice is

ا.
E
Tilgio
What is the specific gravity of ice?
Ans. .922, water at 62° Fahr. being 1.
Will
Fig. 5.-Familiar operation of making a snow ball illustrating regelation.
8.55 per cent greater than that occupied by one pound of water
at the same temperature.
What is specific gravity?
Ans. The weight of a given substance compared with the
weight of some other substance taken as a standard of com-
parison. Water is the standard for liquids and solids.
A
Water
23
What is the work of fusion?
Ans. The latent heat of fusion X the mechanical equivalent
of heat. That is 143.6 × 777.5
111,649 ft. lbs.
What is the point of maximum density of water?
Ans. 39.1° Fahr.
ATMOSPHERIC PRESSURE
What is the point of least density of water?
Ans. The temperature at which steam begins to form.
OPEN
212
FAHR.
၁၀
=
O
CLOSED
327.8°
.FAHR.
100 LBS.
ABSOLUTE PRESSURE)


Figs. 6 and 7.-Water boiling at atmospheric pressure and at 100 lbs. pressure
absolute. Note temperatures.
Upon what does the boiling point of water depend?
Ans. Upon the pressure as shown in figs. 6 and 7.
What is the boiling point at atmospheric pressure?
Ans. It depends upon what is the atmospheric pressure.
Don't you know that the atmospheric pressure is constantly varying
with weather conditions and is affected by the altitude?
24
Water
This is no catch question — what is the boiling point at
sea level when the barometer reads 14.696 ins. the stand-
ard atmosphere?
Ans. 212° Fahr.
Does the boiling point of water vary; if so, how?
Ans. Yes. It is lowered with decrease of pressure.
At an elevation of say 5,000 ft., water will boil at a temperature of
202° Fahr.
What is the freezing point of sea water?
Ans. 27° Fahr.
What cooking utensil depends for its operation on the
effect of pressure on the boiling point?
Ans. The pressure cooker.
Must water be "hot" to boil?
Ans. No.
Why?
Ans. The boiling point depends upon the pressure.
For instance water under a 28 in. vacuum will boil at 100°; if the
vacuum be increased to 29.74 ins. it will boil at 32° Fahr.
What cooking utensil depends for its operation upon a
variation of pressure?
Ans. The glass coffee brewer. See figs. 8 to 10.
Why do some waters give considerable trouble in boiling
operation?
Ans. Because they contain scale forming ingredients.
Water
25
What property of water causes circulation in boilers?
Ans. Its change in weight with change of temperature. That
is, the higher the temperature of water the less it weighs.
The circulation is considerably increased by the formation of steam
bubbles.
FILTER
How does this cause circulation in boilers?
Ans. The heavy low temperature water sinks to the lowest
point in the boiler and displaces the light high temperature
water, thus causing continuous circulation as long as there is
a temperature difference in different parts of the boiler.
TUBE
PRESSURE
COFFEE |||||
11
AIR
TIGHT
JOINT
WATER
SOURCE OF
HEAT
VACUUM


F
BREWED COFFEE
F
Figs. 8 to 10.—The familiar glass coffee brewer illustrating the variation of pres-
sure upon which its operation depends. Fig. 8, heat applied, pressure generated
and the water being forced into the upper container; fig. 9, completion of the
upflow part of the cycle; fig. 10, cooling period producing vacuum which causes
excess pressure of atmosphere to force the liquid down into the lower globe.
26
Water
What is this kind of circulation called?
Ans. Thermal circulation.
What part of a boiler is subjected to the greatest pressure
in operation?
Ans. The lowest point.
Why?
Ans. The pressure at the lowest point is that due to the
steam pressure+the weight of the water.
What catch question does this circumstance cause
"smart" examiners to spring upon the unsuspecting
person taking the examination?
Ans. It is: Does the steam gauge register the correct pressure
in the boiler and why?
What is the answer to this catch question?
Ans. The answer is no, except at the particular point where
the gauge is connected to the boiler.
What is the object of these smart catch questions?
Ans. To test the reasoning ability of the applicant to analyze.
The author considers some of the catch questions a little too smart.
What is the weight of one cu. ft. of water at maximum
density?
Ans. It is generally taken at the figure given by Rankine
62.425 lbs. The figure 62.5 is often used as approximate.
What is the weight of one U. S. gallon of water?
Ans. The U. S. gallon (231 cu. ins.) of water weighs 8% lbs.
Water
27
,
Is this weight correct? Why?
Ans. It is correct only when the water is at a temperature
of 65° Fahr.
LOSS OF HEAD
How does the pressure of water due to its weight, vary?
Ans. It varies with the head.

DYNAMIC HEAD
"
STATIC HEAD
DYNAMIC HEAD
SPORTEUNEN PRISMPUNG TULARIADENI
STATIC HEAD
Figs. 11 and 12.—Static and dynamic head illustrating also loss of head.
How?
Ans. It is equal to .43302 lb. per sq. in. for every foot of
(static) head, at 62° Fahr.
Define head.
Ans. The depth, that is, height of water in a vessel, pipe or
conduit which is a measure of the pressure at a given point
below the surface.
28
Water
Name and define two kinds of head.
Ans. Static head relating to water at rest; dynamic head
relating to water in motion static head+frictional resistance.
See figs. 11 and 12.
What ridiculous mistake is made by the ignorantia in
defining head?
Ans. The practice of considering lift as part of the head.

TRUE
LEVEL
FALSE
LEVEL
HERZIEHHIKOW
COLD,
HEAVY
WATER
HOT, LIGHT
WATER
Fig. 13.-False water level registered by water gauge due to difference in den-
sity of the water in the gauge and water in the boiler.
Does the water gauge show the correct height of the
water in the boiler, and why?
Ans. It does not, in fact it registers a lower water level than
inside the boiler because the water in the gauge is at a lower
Water
29
temperature than the water in the boiler and is accordingly
heavier which causes it to sink to a lower level in establishing
equilibrium. See fig. 13.
{
What is contained in water besides water?
Ans. Water contains air mechanically mixed with it which
is liberated in the condensation of steam.
STEAM BUBBLES
COLD WATER
LIBERATED
AIR
(RISING)


BOILING WATER
Figs. 14 and 15.-Cold and boiling water illustrating the liberation of air
"mechanically mixed" in the cold water.
What important provision must be made for this and
why?
Ans. Surface condensers must be provided with air pumps
(ignorantly called "vacuum" pumps) to remove the liberated
air and condensate (in the case of wet air numps) from the
condenser. See figs. 14 and 15.
Why ignorantly called "vacuum" pumps?
30
Water
Ans. Because it is condensation of steam that creates the
vacuum and not the removal of the air.
In fact without an air pump a vacuum would last quite some time
in a condenser. The air pump prevents the condenser gradually filling
with air and lowering the vacuum.
In other words, the condensation of steam creates the vacuum and the
air pump maintains the vacuum.
Steam
31
CHAPTER 4
Steam
It is important that those who install or have charge of
boilers, should have some knowledge of the nature of steam, its
formation and behavior under various conditions.
Unfortunately this knowledge is usually sadly lacking. This knowl-
edge should be of a higher order than that possessed by some individuals
who call British thermal units, British "terminal" units.
What is steam?
Ans. The vapor of water.
What are its characteristics?
Ans. It is a colorless expansive invisible gas.
What is the "white cloud" seen issuing from an exhaust
pipe and ignorantly called steam by greenhorns?
Ans. It is not steam at all but in reality a fog of minute
liquid particles formed by condensation. In other words, it is
finely divided condensate.
What causes the steam to change into a white cloud?
Ans. Exposure to a temperature lower than that corres-
ponding to its pressure.
For instance, steam exhausting into the atmosphere encounters a
temperature of say ordinarily between 60° and 80° and condensation
32
Steam
immediately takes place forming the "white cloud." If the temperature
were 212° Fahr. no condensation would take place and the exhaust
would remain steam, which is invisible.
What is understood by the term "steam" unqualified?
Ans. It is generally understood to mean saturated steam
and not so-called steam.

WET
STEAM
-SATURATED
STEAM
SUPERHEATED
STEAM
Fig. 1.-Safety valve blowing, illustrating the three kinds of steam.
With respect to power what is steam?
Ans. The medium or working substance by which some of the
heat energy liberated from the fuel by combustion is transmitted
to the engine and partly converted into mechanical work.
Steam
33
What an Engineer should know
about steam
How is steam classified according to its quality?
Ans. As saturated, dry, wet, superheated, highly superheated
or gaseous, as shown in fig. 1.
What is saturated steam?
Ans. Steam of a temperature due to its pressure.
This is the important definition, and the one expected by the examiner
in an examination.
Why is the last answer important in an examination?
Ans. Because strictly speaking it specifies the only condition
in which true steam can exist.
What is wet steam?
Ans. Steam containing intermingled moisture, mist, or spray.
What is dry steam?
Ans. Steam containing no moisture. It may be either satu-
rated or super-heated steam.
What is super-heated steam?
Ans. Steam having a temperature higher than that corres-
ponding to its pressure.
What is gaseous steam?
Ans. A ridiculous classification for highly super-heated steam
because both super-heated steam and "gaseous" steam are
gaseous.
How is steam classified with respect to pressure?

34
Steam
COME
5 lbs.
160 lbs.
25 lbs.
43at him.
Iban ében!
GENERATOR
GASOLING
FANE
White
**Flash
system
MA
BURBER
ge
306
80 lbs.
Standard stationary pressure
250 lbs.
WATE FIGH
FLOS MOTOR
500 lbs.
NEREDE
100
THROTTLE
f
MATER PERT
STEAM
PRESSURES
From 5 lbs. to 500 lbs.
220 lbs. Figs. 2 to 8.--Examples illustrating use of steam at various pressures.
Steam
35
Ans. 1, Vapor; 2, atmospheric; 3, low pressure; 4, medium
pressure; 5, high pressure; 6, extra high pressure.
What is the application of atmospheric pressure steam?
Ans. In steam heating systems in which the pressure is only
a few ounces above or below atmosphere pressure.
What is the application of low pressure steam?
Ans. In ordinary steam heating systems working at approxi-
mately 5 to 10 lbs. per sq. in.
What is the application of medium pressure?
Ans. For power plants working up to 150 lbs. per sq. in.
What is the standard "stationary" working pressure?
Ans. 80 lbs. per sq. in.
What is the application of high pressure steam?
Ans. For plants operating at pressures from 150 lbs. to 300
lbs. approximately.
What is the application of extra high pressure steam?
Ans. For plants operating from 300 lbs. to over 2,000 lbs.
per sq. in.
Give examples of plants using various pressures.
Ans. Vapor, atmospheric and low pressure applications
already given. Stationary engines (ordinary slide valves) 80
lbs.; road rollers 100-120 lbs.; marine engines; compound
100-150 lbs.; triple expansion 160-250 lbs.; locomotives 200-
350 lbs.; pressures above in large power plants (Edison stations,
etc.) and special applications. See figs. 2 to 8.
2
:
36
Steam
The formation of Steam
VAPORIZATION
How much heat does it take to generate steam?
Ans. The sensible heat+the internal latent heat+the ex-
ternal latent heat.
INDICATED BY
"SENSE" OF FEELING
What is the sensible heat and why so called?
Ans. That part of heat which produces a rise in temperature,
as shown by the thermometer, in distinction from latent heat.
So called because it is sensible to the touch.
SENSIBLE HEAT

RADIATOR
Fig. 9.-Familiar radiator exmple of sensible heat.
Steam
37
What is the British thermal unit (B.t.u.)
1
Ans. The 180 part of the heat required to raise the tem-
perature of one pound of water from 32° to 212° Fahr.*
INTERNAL
LATENT HEAT
THE BUSINESS OF WAITING
FOR THE COFFEE POT TO BOIL
What is latent heat?
Ans. That quantity of heat which disappears or becomes con-
cealed in a body while producing some change in it other than
a rise of temperature.
EXTERNAL
LATENT HEAT
WHEN THE POT BOILS


Mill
MZ

Figs. 10 and 11.-Domestic illustrations of internal and external latent
heats. The author does not agree with the generally accepted calculation for
the external latent heat or external work of vaporization in the formation of
steam and considers it wrong in principle. See Audels Engineers and Mechan-
ics Guide, Vol. 1, page 31, also Vol. 5, page 1795 by the author.
*NOTE.-Strictly speaking, this is the mean heat unit (now generally accepted)
which gives 180 instead of 180.3 units and the latent heat as 970.4 instead of
969.7 units.
NOTE.-Strictly speaking the word unqualified is the total latent heat
internal latent heat +external latent heat.
=
38
Steam
What is is the internal latent heat?
Ans. The amount of heat that water will absorb at the boiling
point without a change in temperatures.

WET STEAM
CONDENSATION ON
SIDE OF VESSEL
EXPLOSION OF
BUBBLE
DISENGAGEMENT
HEATED CENTRAL
PORTION
COOL OUTER
PORTION
EXPANSION OF THE
STEAM GLOBULES
GLOBULE DISENGAG-
ING FROM HEATING
SURFACE (INITIAL
DISENGAGEMENT)
HEATING SURFACE
W
EVAPORATION
WHITE CLOUD
SPOPULARLY KNOWN,
AS "STEAM"
SATURATED OR
DRY STEAM
DISENGAGING
SURFACE
VAPORIZATION
STEAM BUBBLES
ATMOSPHERIC
PRESSURE
COLLAPSE OF
GLOBULE
(CONDENSATION
COMPLETE)
CONDENSATION
EXPANSION
·CHANGE OF STATE
ATMOSPHERIC PRESS
JRE PLUS PRESSURE
DUE TO THE HEAD CE
THE WATER.
HEAT SUPPLY
Fig. 12.-The phenomena of vaporization or process of "boiling."
What is the external latent heat?
Ans. When vaporization takes place, the amount of heat
†NOTE.—In other words: The amount of heat which must be absorbed by water
at the boiling point before vaporization will begin. See fig. 16.
Steam
39
required because of the work in pushing back the atmosphere
to make room for the steam‡. See fig. 16.
What is the meaning of "from and at 212° Fahr."?
Ans. In boiler operation, it is an evaporation that would be
the equivalent of the actual evaporation when the feed water
enters the boiler at 212° Fahr. and steam is formed at
standard atmospheric pressure.

FEED WATER
212
FAHR
A
HEATER
212
^^)
FAHR
་
F
ހ |
//////-----ÿÿ
S
Fig.13.-Evaporation "from and at 212° Fahr."
INOTE.-The author does not agree with the generally accepted calculation
for the external latent heat or external work of vaporization and holds that it is
wrong in principle. The author holds that "Since the water already existed at the
beginning of vaporization, the atmosphere was already displaced to the extent of
the volume occupied by the water, and therefore this displacement must not be
considered as contributing to the external work done by the steam during its
formation as indicated in fig. 15. For the author's theory see Audel's Engineers
& Mechanics Guide, Vol. I, page 31.
40
Steam
and actual piston movement.
Figs. 14 to 16 -Three stages in the formation of steam; stage 3 (fig. 16) for
external latent heat illustrates author's basis for calculation. Note erroneous
.0167 FT.
27.7 CU INS
28.88 CO INS
THE SENSIBLE HEAT
O
I LB. OF WATER AT 32
212-32-180 B.T.U. REQUIRED TO RAISE THE
TEMPERATURE TO THE BOILING POINT
MAIN
THE INTERNAL LATENT HEAT
897.6 HEAT UNITS REQUIRED
BEFORE STEAM FORMS
VOLUME ORIGINALLY OCCUPIED BY THE WATER
VOLUME 26.79 CUBIC FEET
********
****
ONE POUND
OF
SATURATED STEAM AT 212:
...
PISTON MOVEMENT AS ERRONEOUSLY ASSUMED
26.7733 FEET-
ACTUAL PISTON MOVEMENT
:::
STAGE 1
STAGE 2
STAGE 3
The Three Stages



Steam
41
Describe the process of boiling; that is, vaporization.
Ans. When heat is applied to a liquid such as a quantity of
water in a boiler, the lower layers are first warmed. These
expand and rise to the top, their place being taken by the colder
layers from above, and by this process the mass is warmed
through. The air which is contained in the water expands as
the temperature is raised, and rises to the top. The temperature
of the lower layers in time becomes raised up to slightly above
the atmospheric boiling point, 212° F., and steam is formed,
as bubbles adhering to the heating surface; these bubbles, by
expansion, become large enough to detach themselves and rise
into the colder layers above. On reaching the colder layers, they
condense and their sudden collapse sets up vibration in the
water which is communicated to the metal of the containing
vessel, causing the familiar "singing" heard at this stage, and the
steam which composes the bubbles gives up its latent heat, thus
warming the water until the whole mass is at the boiling point.
The Total Heat of Saturated Steam.-In transforming
one pound of water into saturated steam at atmospheric
pressure the amount of heat to be supplied, as already shown,
may be tabulated as follows:
Stage 1- The sensible heat required to raise the tem-
perature of the water to the boiling point..
Stage 2-The internal latent heat absorbed by the water
at 212° before a change of state takes place..
Stage 3―The external latent heat required for the work
to be done on the atmosphere.
180 B.t.u.
897.51 ""66
72.89 “ “ “f
1,150.4
666666
The sum of these three items, is known as the total heat above
32° F., this temperature being taken as the starting point.
42
Steam
!
Expressed as an equation.
Sensible heat+internal latent heat+external latent heat
180 + 897.51
+
72.89
In the foregoing where is the sensible heat?
Ans. In the water.
Where is the total heat?
Ans. In the steam.
CIRCULATING
WATER
D
CONDENSATE
HOT WELL-
WWW
W
M
B
E
C
COOLING
SURFACE
CONDENSER
DISCHARGE
..:
UNS
total heat
=1,150.4 B.t.u.
-=-**

Mu
STEAM
I
A
Fig. 17.-The condensation of steam. If water be boiled in a flask A, and the
steam thus produced led off through pipe C, having a coiled section surrounded
by cold water, it will here be cooled below the boiling point, and will therefore
condense, the condensate passing out into the receptacle B, as water. The
cooling or "circulating" water enters the condenser at the lowest point D, and
leaves at the highest point E.
Steam
43
STEAM
LINE
Condensation
What is condensation?
Ans. The change of state of a substance from the gaseous
to the liquid form.
What is the liquid called?
Ans. The condensate.

……
COOLING
WATER STEAM
LINE
HIT
VACUUM
COOLING SPRAY
Figs. 18 and 19. -Newcomen's atmospheric engine illustrating effect of con-
denser in reducing the back pressure due to the atmosphere, which, in effect,
makes the forward pressure of the atmosphere available to force the piston
down on the return stroke.
J
What causes condensation?
Ans. A reduction of temperature below that corresponding
to the pressure.
What happens when steam condenses?
Ans. The water from which the steam was originally formed
contained a small percentage of air mechanically mixed with it
and this air does not re-combine with the water of condensation,
but remains liberated in a condenser or in the pipes of a
steam heating plant.
44
Steam
Effect of Pressure on Boiling Point
80.3 LBS
GAUGE
AIR
PUMP
་་་་་་་་
ICE
τὸ
25.
29.74 IN
VACUUM
32°
FAHR.
29.74 IN
VACUUM
4
TOP OPEN.
TO. ATMOSPHERE
14.7 LBS.
ABS
°212™°
M
Figs. 20 to 23.-Variation of the boiling point with change of pressure.
How is this air removed?
Ans. By air pumps and air valves respectively.
200
95 LBS.
ABS
324.1°
585.3 LBS
GAUGE
COO
600 LBS.
ABS
486.6
J




Steam
45
How was the principle of condensation first utilized?
Ans. The early engineers discovered that by condensation
the pressure of the atmosphere is made available for doing
work, resulting in the introduction of so called "atmospheric
engines." See figs. 18 and 19.
Steam above Atmospheric Pressure
When vaporization takes place in a closed vessel, what
happens due to rising temperature?
Ans. The pressure rises until equilibrium between tempera-
ture and pressure is re-established.
When equilibrium is established, what is the tempera-
ture of equilibrium called?
Ans. The boiling point.
How does the boiling point vary?
Ans. The higher the pressure, the higher the boiling point,
as shown in figs. 20 to 23.
Why?
Ans. More heat must be added to the water because of the
increasing amount of work that must be done to push back the
air to make room for the steam. That is, because of the increas-
ing external latent heat in establishing "thermal equilibrium.”
The Steam Table
The amount of study of the steam table and knowledge
absorbed are not always in proportion and sometimes it hap-
46
Steam
pens after considerable study one gets "tripped up" in using
the steam table in solving problems.
What is the steam table?
Ans. By definition: The properties of steam for various
pressures given in tabulated form.
Name two kinds of steam table.
Ans. 1, Properties of Saturated Steam; 2, Properties of
Super-heated Steam.
The following examples illustrate how to use the steam table:
Example.-How many heat units are saved in heating 25 lbs. of feed
water from 90° to 212°?
In column 4, total heat in the water at 212° = 180.
In column 4, total heat in the water at 90° = 58
= 122
Heat units saved per lb. of feed water
Total heat units saved = 122×25=3,050 B. t. u.
Example.-What is the weight of 20 cu. ft. of steam at 150 lbs. absolute
pressure?
The weight of 1 cu. ft. steam at 150 lbs. abs. is given in column 8 at
.332 lb. Twenty cu. ft. then will weigh: .332×20=6.64 lbs.
Example.-How much more heat is required to generate 26 lbs. of steam
at 150 lbs. abs., than at 90 lbs. abs.
In column 5 total heat in steam at 150 lbs. abs. 1,193.4
In column 5 total heat in steam at 90 lbs. abs. =1,184.4
Excess heat required per pound (weight)
Total for 26 lbs. =9×26=234 B. t. u.'
--
Example.-How much heat is absorbed by the cooling water, if a con-
lensing engine exhaust 17 lbs. of steam per hour at a terminal pressure
of 18 lbs. absolute into a 28½ inch vacuum.
Heat to be absorbed per lb. of steam
Total heat absorbed by the cooling water per hour
1,096.2×17=18,635.4 B. t. u.
9 B. t. u.
•
In column 5, total heat in the steam at 18'lbs. abs.
In column 4, total heat in the water with 28½" vacuum=
= 1,154.20
58.00
= 1,096.2
Steam
47
Vacuum, Inches of
Mercury.
Properties of Saturated Steam
Condensed from Marks and Davis' Steam Tables and Diagrams, 1909, by
permission of the publishers, Longmans, Green & Co.

29.74
29 67
29.56
29.40
29 18
11.60
Pressure,
Absolute
Lbs. per Sq. In.
28.89
28.50
28.00
27.88 1
25.85 2
23.81 3
21.78
19.74
17.70
15.67
13.63
0.0886 32
0.1217
40
0 1780 50
0.2562
60
0.3626 70
0.505 80
0.696 90
0.246 100
450780C2RL
10.3
11.3
12.3
9
9.56 10
7.52 11
5.49 12
3.45 13
1.42 14
lbs.
gauge 14.70
0.3 15
1.3 16
2.3
17
3.3
18
4.3
19
5.3
20
6.3
21
7.3
8.3
9.3
222222**27
Temperature,
Fahrenheit.
23
24
25
26
In the Water
Total Heat
above 32° F
8 Heat-Units.
પ્
0.00
8.05
In the Steam
18.08
28.08
38.06
48.03
58.00
67.97
H
Heat-Units.
Latent Heat, L=
H-h Heat-Units.
180.0
1150.4
212
213.0
181.0 1150.7
216.3 184.4 1152.0
219.4 187.5
1153.1
222.4 190.5
1154.2
225.2 193.4
1155.2
228.0 196.1
1156.2
230.6 198.8
1157:1
233.1
201.3
1158.0
235.5
203.8 1158.8
237.8
206.1 1159.6
240.1 208.4 1160.4
242.2 210.6 1161.2
244.4 212.7 1161.9
1073.4 1073.4 3294
1076.9 1068.9 2438
0.000304 0.0000 2.1832
0.000410 0.0162
0.000587 0.0361
1081.4
1063.3 1702
2.1394
2.0865
2.0358
1085.9
1057.8 1208
0.000828 0.0555
1090.3
1052.3 871
0.001148 0.0745 1.9868
1094.8 1046.7 636.8 0.001570 0.0932
1.9398
0.002131 0.1114
1.8944
1099.2 1041.2 469.3
1103.6 1035.6
0.002851 0.1295
1.8505
101.83
69.8
1104.4 1034.6
350.8
333.0
173.5
1.8427
0.00300 0.1327
0.00576
126.15
94.0
1115.0 1021.0
1.7431
0.1749
118.5 0.00845 0.2008
141.52
109.4
1121.6
1.6840
1012.3
1005.7
153.01 120.9
1126.5
90.5 0.01107 0.2198
1.6416
162.28 130.1 1130.5
1000.3
73.33 0.01364 0.2348
1.6084
995.8
61.89 0.01616 0.2471 1.5814
991.8
170.06 137.9 1133.7
176.85 144.7 1136.5
182.86 150.8 1139.0
188.27 156.2 1141.1
193.22 161:1 1143.1
53.56 0.01867 0.2579 1.5582
47.27 0.02115 0.2673 1.5380
988.2
985.0
42.36 0.02361 0.2756 1..5202
38.38 0.02606
982.0
1.5042
0.2832
35.10 0.02849 0.2902
197.75 165.7
1144.9
979.2
1.4895
201.96 169.9
1146.5
976.6
32.36 0.03090 | 0.2967
1.4760
205.87 173.8
1148.0
974.2
1.4639
30.03 0.03330 | 0.3025
28.02 0.03569 0.3081
209.55 177.5
1149.4
971.9
1.4523
970.4
969.7
967.6
965.6
963.7
961.8
960.0
958.3
956.7
955.1
953.5
952.0
950.6
949.2
Volume, Cu. Ft. in.
1 Lb. of Steam.
·
Weight of 1 Cu. Ft.
Steam, Lb.
Entropy of the
Water.
26.79 0.03732 0.3118
26.27 0.03806 0.3133
24.79 0.04042 0.3183
23.38 0.04277
0.3229
22.16 0.04512 0.3273
21.07 0.04746
0.3315
20.08 0.04980
0.3355
19.18 0.05213
0.3393
18.37 0.05445
0.3430
17.62 0.05676 | 0.3465
16.93 0.05907
16.30 0.0614
15.72 0.0636
15.18 0.0659
Entropy of Evapo-
ration.
1.4447
1.4416
1.4311
1.4215
1.4127
1.4045
1.3965
1.3887
1.3811 ·
1.3739
0.3499 1.3670
0.3532 1.3604
0.3564 1.3542
0.3594 1.3483
48
Steam
Gauge Pressure,
Lbs. per Sq. In.
Pressure,
13.3
28
14.3 29
15.3 30
16.3 31
17.3 32
18.3
33
19.3
34
20.3 35
21.3 36
22.3 37
23.3
38
24.3 39
25.3 40
26.3
41
27.3 42
28.3
43
29.3
44
30.3 45
31.3 46
32.3 47
33.3 48
34.3 49
35.3 50
36.3 51
37.3
38.3
Absolute
Lbs. per sq. in.
41.3
42.3
INKHRONAROJ
52
39.3 54
53
40.3 55
56
57
43.3
14.3 59
45.3 60
46.3 61
47.3 62
48.3 63
49.3 64
50.3 65
51.3 66
52.3 67
58
Properties of Saturated Steam-Continued
Total Heat
above 32° F
Temperature,
Fahrenheit.
In the water
Heat-Units.
In the Steam
H
Heat-Units.
246.4
214.8 1162.6
248.4
216.8
1163.2
250.3
218.8
1163.9
252.2
220.7
1164.5
254.1
222.6
1165.1
255.8
224.4
1165.7
257.6
226.2
1166.3
259.3
227.9
1166.8
261.0
229.6
1167.3
262.6
231.3
1167.8
264.2
232.9
1168.4
265.8
234.5
1168.9
267.3
236.1
1169.4
268.7
237.6
1169.8.
270.2
239.1
1170.3
271.7
240.5
1170.7
273.1
242.0
1171.2
274.5
243.4
1171.6
275.8
244.8
1172.0
277.2
246.1
1172.4
278.5
247.5
1172.8
279.8
248.8
1173.2
281.0 250.1
1173.6
282.3 251.4
1174.0
283.5 252.6
1174.3
284.7 253.9
1174.7
285.9 255.1
1175.0
287.1
256.3
1175.4
288.2 257.5
1175.7
289.4 258.7 1176.0
290.5 259.8
1176.4
291.6 261.0
1176.7
292.7
262.1 1177.0
293.8 263.2
1177:3
1177.6
294.9 264.3
295.9 265.4
1177.9
297.0 266.4
1178.2
298.0 267.5 1178.5
299.0 268.5 1178.8
300.0
269.6
1179.0
Latent Heat, L=
H-h Heat-Units.
947.8
946.4
945.1
943.8
942.5
941.3
940.1
938.9
937.7
936.6
935.5
934.4
933.3
932.2
931.2
930.2
929.2
928.2
927.2
926.3
925.3
924.4
923.5
922.6
921.7
920.8
919.9
919.0
918.2
917.4
916.5
915.7
914.9
914.1
913.3
912.5
911.8
911.0
910.2
909.5
Volume, Cu. Ft. in
1 Lb. of Steam.
Weight of 1 Cu. Ft.
Steam, Lb.
14.67 0.0682
14.19 0.0705
13.74 0.0728
13.32 0.0751
12.93 0.0773
12.57 0.0795
12.22 0.0818
11.89 0.0841
11.58 0.0863
11.29 0.0886
11.01 0.0908
10.74 0.0931
10.49 0.0953
10.25 0.0976
10.02 0.0998
9.80 0.1020
9.59 0.1043
9.39 0.1065
9.20 0.1087
9.02 0.1109
8.84 0.1131
8.67 0.1153
8.51 0.1175
8.35 0.1197
8.20 0:1219
8.05 0.1241
7.91 0.1263
7.78 0.1285
7.65 0.1307
7.52 0.1329
7.40 0.1350
7.28 0.1372
7.17 0.1394
7.06 0.1416
6.95 0.1438
6.85 0.1460
6.75 0.1482
6.65 0.1503
6.56 0.1525
6.47 0.1547
Entropy of the
Water.
Entropy of Evapo-
ration.

0.3623 1.3425
0.3652
1.3367
0.3680
1.3311
0.3707 1.3257
0.3733 1.3205
0.3759 1.3155
0.3784 1.3107
0.3808
1.3060
0.3832
1.3014
0.3855
1.2969
0.3877 1.2925
0.3899
1.2882
0.3920
1.2841
0.3941
1.2800
0.3962 1.2759
0.3982 1.2720
0.4002
1.2681
0.4021
1.2644
0.4040 1.2607
0.4059
1.2571
1.2536
0.4077
0.4095 1.2502
0.4113 1.2468
0.4130 1.2435
0.4147 1.2402
0.4164 1.2370
0.4180 1.2339
0.4196 1.2309
0.4212 1.2278
0.4227 1.2248
0.4242
1.2218
1.2189
0.4257
0.4272 | 1.2160
0.4287 1.2132
0.4302 1.2104
0.4316 1.2077
0.4330 1.2050
0.4344 1.2024
0.4358 1.1998
0.4371 1.1972
Steam
49
Gauge Pressure,
Lbs. per Sq. In.
53.3
54.3
Pressure,
Absolute
Lbs. per sq. in.
~~~ZN8%
68
70
55.3
56.3
57.3
72
58.3 73
59.3
74
60.3
75
61.3 76
62.3
PERRO ≈≈**858
78
63.3
64.3 79
65.3 80
66.3 81
67.3 82
68.3
83
69.3 84
70.3
71.3
86
72.3 87
73.3
74.3 89
75.3
90
76.3 91
77.3
92
78.3 93
79.3 94
80.3 95
81.3 96
82.3 97
83.3 98
84.3 99
85.3 100
87.3 102
89.3 104
91.3 106
93.3 108
95.3 110
97.3 112
99.3 114
Properties of Saturated Steam-Continued
Total Heat
above 32° F

Temperature,
Fahrenheit.
In the water
14
327.1
327.8
Heat-Units.
311.2
312.0 282.0
312.9
282.9
313.8 283.8
314.6 284.6
In the Steam
Heat-Units.
H
301.0 270.6 1179.3 908.7
302.0 271.6 1179.6
302.9
908.0
272.6
1179.8
907.2
303.9
273.6
1180.1
906.5
304.8 274.5
1180.4
905.8
305.8 275.5
1180.6
905.1
306.7 276.5
1180.9
904.4
307.6. 277.4 1181.1
903.7
308.5 278.3
1181.4
903.0
309.4 279.3
1181.6
902.3
310.3
280.2
1181.8
901.7
281.1
1182.1
901.0
1182.3
900.3
1182.5
899.7
1182.8
899.0
1183.0
898.4
315.4 285.5
1183.2
897.7
316.3 286.3
1183.4
897.1
317.1 287.2
1183.6
896.4
317.9 288.0
1183.8
895.8
318.7
288.9
1184.0
895.2
319.5 289.7
1184.2
894.6
320.3 290.5
1184.4
893.9
321.1 291.3
1184.6
893.3
321.8
292.1
1184.8
892.7
322.6
323.4
292.9 1185.0
892.1
293.7 1185.2
891.5
324.1 294.5
1185.4
890.9
324.9
295.3
1185.6
890.3
325.6 296.1
1185.8
889.7
326.4 296.8
1186.0
889.2
297.6
1186.2
888.6
298.3
1186.3 888.0
329.3 299.8
1186.7
886.9
330.7
301.3
1187.0
885.8
332.0
302.7 1187.4
884.7
333.4 304.1 1187.7
334.8 305.5
1188.0
306.9 1188.4
883.6
882.5
881.4
880.4
336.1
337.4 308.3 1188.7
Latent Heat, L=
H-h Heat-Units.
Volume, Cu. Ft. in
1 Lb. of Steam.
4.89
4.84
Weight of 1 Cu. Ft.
Steam, Lb.
4.79
4.74
4.69
Entropy of the
Water.
6.20
6.38 0.1569 0.4385 1.1946
6.29 0.1590 0.4398 1.1921
0.
0.1612 0.4411 1.1896
0.1634 0.4424 1.1872
0.1656 0.4437 1.1848
0.1678
0.1678 0.4449
6.12
6.04
5.96
5.89
0.1699 | 0.4462
0.4462
5.81
0.1721 0.4474
0.1743
5.74
0.4487
5.67 0.1764 0.4499
5.60
0.1786 | 0.4511
5.54
0.4511
0.1808 0.4523
0.1829
5.47
0.4535
5.41
0.1851 0.4546
5.34
0.1873 | 0.4557
5.28
0.1894 0.4568
5.22
0.1915 | 0.4579
5.16
0.1937 0.4590
5.10
0.1959
5.05 0.1980
5.00
4.94
Entropy of Evapo-
ration,
4.65
4.60
4.56
4.51
4.47
0.2215 0.4724
|
0.2237 | 0.4733
0.4733
4.429 0.2258 | 0.4743
4.347 0.2300 | 0.4762
4.268 0.2343 0.4780
4.192 0.2336 | 0.4798
4.118 0.2429 | 0.4816
4.047 0.2472 0.4834
3,978 0.2514 0.4852
|
3.912 0.2556 | 0.4869
0.4869
1.1825
1.1801
1.1778
1.1755
1.1732
1.1710
1.1687
1.1665
1.1644
1.1623
1.1602
1.1581
1.1561
1.1540
0.4601
0.4612 1.1520
1.1500
1.1481
0.2001 0.4623
0.2023 | 0.4633
|
0.2044 0.4644
0.2065 0.4654
0.2087 | 0.4664
1.1461
1.1442
0.4664 1.1423
0.2109 | 0.4674 | 1.1404
0.2130 | 0.4684 | 1.1385
0.2151 0.4694 1.1367
0.2172 0.4704 1.1348
|
0.2193 0.4714 1.1330
1.1312
1.1295
1.1277
1.1242
1.1208
1.1174
1.1141
1.1108
1.1076
1.1045
50
Steam
Gauge Pressure,
Lbs. per Sq. In.
Pressure,
Lbs. per Sq. In.
Absolute
Properties of Saturated Steam-Continued
Total Heat
above 32° F

Temperature,
Fahrenheit.
338.7
340.0
341.3
In the Water
342.5
343.8
345.0
346.2
347.4
348.5
349.7
4
Heat-Units.
101.3
116
103.3 118
105.3 120
312.3
107.3 122
313.6
109.3 124
314.9
111.3 126
316.2
113.3 128
317.4
115.3 130
318.6
117.3 132
319 9
119.3 134
321.1
121.3 136 350.8
322.3
123.3 138
352.0
323.4
125.3 140
353.1
324.6
325.8
127.3 142 354.2
129.3 144 355.3 326.9
328.0
329.1
131.3 146 356.3
133.3 148 357.4
135.3 150
137.3 152
139.3 154
332.4
333.5
334.6
358.5 330.2
359.5 331.4
360.5
141.3 156 361.6
143.3 158 362.6
145.3 160 363.6
147.3 162 364.6 336.7
149.3 164 365.6 337.7
151.3 166 366.5 338.7
339.7
335.6
153.3 168 367.5
155.3 170
157.3 172
159.3 174
368.5 340.7
369.4
341.7
370.4
342.7
161.3 176 371.3
343.7
344.7
163.3 178 372.2
165.3 180 373.1 345.6
167.3 182 374.0 346.6
169.3 184 374.9 347.6
171.3 186 375.8 348.5
173.3 188 376.7 349.4
175.3 190 377.6 350.4
177.3 192 378.5 351.3
179.3 194 379.3 352.2
In the Steam
Heat-Umts.
H
Latent Heat, L=
H-h Heat-Units
309.6
1189.0 879.3 3.848
311 0 1189.3 878.3
3.786
1189.6 877.2
3.726
1189.8 876.2
3.668
1190.1 875.2
3.611
1190.4 874.2
3.556
1190.7 873.3
3.504
3.452
1191.0 872.3
1191.2 871.3
1191.3 870.4
3.402
3.354
1191.7 869.4
3.308
1192.6 868.5
3.263
3.219
3.175
3.133
3.092
3.052
3.012
2.974
2.938
2.902
2.868
2.834
2.801
2.769
2.737
2.706
2.675
2.645
2.616
2.588
2.560
2.533
2.507
2.481
2.455
2.430
2.406
2.381
2.358
1192.2 867.6
1192.5 866.7
1192.7❘ 865.8
1192.9 864.9
1193.2 864.0
1193.4 863.2
1193.6 862.3
1193.8 861.4
1194.1 860.6
1194.3
859.7
1194.5 858.8
1194.7
858.0
1194.9
857.2
Volume, Cu. Ft. in
1 Lb. of Steam.
1195.1 856.4
1195.3 855.5
1195.4 854.7
1195.6 853.9
1195.8 853.1
1196.0 852.3
1196.2 851.5
1196.4 850.8
1196.6 850.0
1196.8 849.2
1196.9 848.4
1197.1 847.7
1197.3 846.9
1197.4 846.1
1197.6 845.4
Weight of 1 Cu Ft.
Steam, Lb.
Entropy of the
Water.
Entropy of Evapo-
ration.
0 4886
1.1014
0.2599
0.2641
0.4903
0.4919
1.0984
1.0954
0.2683
0.2726
0.4935
1.0924
0.2769
0 4951
1.0895
0.2812
0.4967
0.4967
1.0865
0.2854
0.4982
1.0837
0.2897 0.4998
1 0809
1.0782
0.2939 0.5013
0.2981
1.0755
0.5028
0.3023 0.5043
0.5043 1.0728
0.3065 0.5057 1.0702
0.3107 0.5072
1.0675
0.3150 0.5086
1.0649
0.3192 0.5100 1.0624
0.3234
0.5114 1.0599
0.3276
0.5128
0.5128 1.0574
0.3320
0.3362
0.5142 1.0550
0.5155 | 1.0525
0.3404 0.5169 1.0501
0.3446 0.5182
0.3488 0.5195
1.0477
1.0454
0.5208 1:0431
0.5220
0.5220 1.0409
0.5233 1.0387
0.5245
0.5245
0.3529
0.3570
0.3612
0.3654
0.3696
0.3738
0.3780 0.5281
1.0300
0.3822 0.5293
1.0278
0.3864 0.5305
1.0257
0.3906 0.5317
1.0235
0.3948 0.5328 1.0215
0.3989 0.5339
0.5339 1.0195
0.4031 0.5351
1.0174
0.4073 0.5362 1.0154
0.4115 0.5373
1.0134
1.0114
0.4157 0.5384
1.0365
1.0343
0.5257
0.5257
0.5269 1.0321
0.4199 0.5395 1.0095
0.4241 0.5405 1.0076
Steam
51
Gauge Pressure,
per Sq. In.
Lbs.
Pressure,
**
Absolute
Lbs. per Sq. In.
Properties of Saturated Steam-Continued
Total Heat
above 32° F

Temperature,
Fahrenheit.
In the Water
પ્
Heat-Units.
181.3 196
380.2
353.1
183.3 198 381.0 354.0
185.3 200 381.9
354.9
190.3 205
384.0
357.1
195.3 210
386.0
359.2
200.3 215
388.0
361.4
205.3 220 389.9
363.4
210.3 225
391.9
365.5
367.5
215.3 230 393.8
220.3 235 395.6 369.4
225.3 240 397.4 371.4
399.3 373.3
401.1
375.2
230.3 245
235.3 250
245.3 260
255.3 270
378.9
404:5
407.9 382.5
265.3 280 411.2
386.0
389.4
275.3 290
285.3 300
295.3 310
305.3 320 423.4
315.3 330 426.3
414.4
417.5 392.7
420.5
395.9
399.1
402.2
325.3 340
429.1 405.3
431.9
408.2
335.3 350
345 3 360
355.3 370
434.6
411.2
437.2
414.0
365.3 380 439.8
416.8
375.3 390 442.3
419.5
385.3 400 444.8 422
435.3 450
485.3 500
$535.3 550
456.5 435
467.3 448
477.3 459
585.3 600 486.6 469
Source 684 500
484
542
1062 550
1574 600
604
2265 650
2974
689
3075 700
4300.2 752
† 5017.1 779
5659.9 810.6
In the Steam
Η
Heat-Units.
Latent Heat, L=
H-h Heat-Units.
Volume, Cu. Ft. in
1 Lb. of Steam.
1197.8
1197.9
844.7
843.9
1198.1 843.2
1198.5 841.4
1198.8 839.6
1199.2 837.9
1199.6 836.2
1199.9 834.4
1200.2 832.8
1200.6831.1
Weight of 1 Cu. Ft.
Steam, Lb.
Entropy of the
Water.
Entropy of Evapo-
ration.
2.335 0.4283 0.5416 | 1.0056
2.312 0.4325 0.5426
1.0038
0.437 0.5437 1.0019
2.290
2.237
0.447
0.5463 0.9973
2.187
0.457
0.5488 0.9928
2.138
0.468
0.5513 0.9885
2.091
0.478
0.5538 0.9841
2.046 0.489
0.5562 0.9799
2.004
0.499 0.5586 0.9758
1.964
0.509
0.5610 0.9717
1200.9 829.5
1.924
0.520
0:5633 0.9676
1201.2 827.9
1.887
0.530
0.5655 0.9638
1201.5
826.3
1.850
0.541
0.5676 0.9600
1202.1
823.1
1.782
0.561
0.5719 0.9525
1202.6 820.1
1.718
0.582
0.5760 0.9454
1203.1 | 817.1
1.658
0.603
0.5800 0.9385
1203.6 814.2
1.602
0.624
0.5840 0.9316
1204.1
811.3
1.551
0.645
0.5878 0.9251
1204.5 808.5
1.502
0.666
1204.9 805.8
1.456
0.687
1205.3 803.1
1.413
0.708
1.372
0.729
1205.7 800.4
1206.1 797.8
1.334 0.750
1206.4
795.3
1.298
0.770
1206.8 792.8
1.264
0.791
1207.1
790.3 1.231
0.812
1207.4 787.9 1.200 0.833
1208 786
1.17 0.86
1209 774
1.04
0.96 0.635
1210
762
0.93
1.08
1210
751
0.83
1.20
1210
741
0.76
1.32
1209
725
0.66 1.52
1200
658
0.42 2.36
1176
572
0.27
441
0.16
0.05
0.5915 0.9187
9.5951 0.9125
0.5986 0.9065
0.6020 0.9006
0.6053
0.8949
0.6085
0.8894
0.6116 0.8840
0.6147 0.8788
0.6178 0.8737
0.621 0.868
0.844
0.648 0.822
0.659 0.801
0.670 0.783
0.686 0.755
0.743
0.650
3.75 0.799 0.540
6.2
0.396
*From G. A. Goodenough's tables 1915.
Calculated by J. McFarlane Gray-Proc. Inst. M.E., July, 1889.
52
Steam
What is super-heated steam?
Ans. If a closed vessel containing water and steam be heated,
the pressure of the steam will gradually rise until all the water
has been evaporated. At this point the further addition of heat
will not produce any appreciable increase in pressure but will
cause a rise in temperature in which condition the steam is
said to be superheated, hence, superheated steam is defined as
steam heated to a temperature above that due to its pressure.
What is the object of super-heating steam?
Ans. It reduces and in extreme cases prevents condensation,
thus giving better economy.
What are the disadvantages in using super-heated steam?
Ans. Increased difficulty of securing proper lubrication,
higher first cost and depreciation.
What is the saving due to super-heating?
Ans. According to Ripper, the condensation at cut off is
reduced 1 per cent for each 7.5 degrees of super-heat.
The saving varies considerably with the type of engine, degree of
expansion, etc.
What conditions favor super-heat?
Ans. High degree of expansion of the steam, slow speed,
constant load and high fuel cost.
How much super-heat should be given to the steam?
Ans. For maximum saving possible the degree of super-heat-
ing should be such that the steam is exhausted in a saturated
state (the ideal case).
Steam
53
When is there too much super-heat?
Ans. When the super-heat is high enough to give a super-
heated exhaust.
In practice, does this occur often?
Ans. In practice, it is very seldom that the super-heating is
carried to the extent of giving a super-heated exhaust; in fact,
the exhaust is usually not even saturated but wet.
Is super-heated steam used for locomotives?
Ans. Super-heated steam is quite generally used in locomotive
practice. Its use has resulted in increased steam economy and
less trouble from water of condensation in the cylinders.
What results are obtained when applied to locomotives?
Ans. According to Fernald and Orrok: "The saving in water
consumption per horsepower-hour is reported to be some 10
or 12 per cent over that with saturated steam, with a corres-
ponding saving of 10 to 15 per cent in fuel consumption."
54
Steam
Press.
Abs. Temp.
Lbs. Sat.
per
Steam.
Sq. In.
20
40
60
80
100
120
· 140
130
180
200
220
240
260
Properties of Superheated Steam
(Condensed from Marks and Davis' Steam Tables and Diagrams.)
specific volume in cu. ft. per lb., h=total heat, from water at 32° F. in
B.t.u. per lb., n=entropy, from water at 32°.
Degrees of Superheat.



0
50
100
→
150
200
250 300 400 500 600
228.0 v 20.08 21.69 23.25 24.80 26.33 27.85 29.37 32.39 35.40 38.40
h 1156.2 1179.9 1203.5 1227.1 1250.6 1274.1 1297.6 1344.8 1392.2 1440.0
n 1.7320 1.7652 1.7961 1.8251 1.8524 1.8781 1.9026 1.9479 1.9893 2.0275
267.3 v 10.49 11.33 12.13 12.93 13.70 14.48 15.25 16.78 18.30 19.80
h 1169.4 1194.0 1218.4 1242.4 1266.4 1290.3 1314.1 1361.6 1409.3 1457.4
n 1.6761 1.7089 1.7392 1.7674 1.7940 1.8189 1.8427 1.8867 1.9271 1.9646
292.7 v 7.17 7.75 8.30 8.84 19.36 9.89 10.41 11.43 12.45 13.46
h 1177.0 1202.6 1227.6 1252.11276.41300.41324.3 1372.2|1420.0 1468.2
n 1.6432 1.67611.7062 1.7342 1.7603|1.7849 1.8081 1.8511 1.8908 1.9279
312.0 v 5.47 15.92 6.34 6.75 17.17 7.56 7.95 8.72 19.49 10.24
h 1182.31208.8 1234.3 1259.0 1283.6 1307.81331.9 1379.8 1427 91476.2
n 1.6200 1.6532 1.6833 1.7110 1.7368|1.7612 1.7840 1.8265 1.8658 1.9025
327.8 v 4.43 4.79 5.14 5.47 15.80 6.12 6.44 7.07 7.69 8.31
h 1186.3 1213.8 1239.7 1264.7 1289.4 1313.6 1337.8 1385.9 1434.1 1482.5
n 1.6020 1.6358 1.6658 1.6933 1.7188 1.7428 1.7656 1.8079 1.8468 188.29
341.3 v 3.73 4.04 4.33 14.62 4.89 15.17 5.44 5.96 6.48 6.99
h 1189.6 1217.9 1244.1 1269.3 1294.1 1318.4 1342.7 1391.0 1439.4 1487.8
n 1.5873 1.6216 1.6517 1.6789 1.7041 1.7280 1.7505 1.7924 1.8311 1.8669
353.1 v 3.22 3.49 3.75 4.00 4.24 4.48 4.71 5.16 5.61 16.06
h 1192.2 1221.4 1248.0 1273.3 1298.21322.6 1346.91395.4 1443.8 1492.4
n 1.5747 1.6096|1.6395|1.6666 1.6916 1.7152 1.7376 1.7792 1.8177 1.8533
363.6 v 2.83 3.07 13.30 3.53 3.74 3.95 4.15 4.56 4.95 5.34
h 1194.5 1224.5 1251.3 1276.8 1301.7 1326.2 1350.6 1399.3 1447.9 1496.6
n 1.5639 1.5993 1.6292 1.6561 1.6810 1.7043 1.7266 1.7680 1.8063 1.8418
373.1 v 2.53 2.75 2.96 3.16 3.35 3.54 3.72 4.09 4.44 4.78
h 1196.4 1227.2 1254.3 1279.9 1304.8 1329.5 1353.9 1402.7 1451.4 1500.3
n 1.5543 1.5904 1.6201 1.6468 1.6716 1.6948 1.7169 1.7581 1.7962 1.8316
381.9 v 2.29 2.49 2.68 12.86 3.04 3.21 3.38 3.71 4.03 4.34
h1198.1 1229.8 1257.1 1282.6 1307.7 1332.4 1357.0 1405.9 1454.7 1503.7
n 1.5456 1.5823 1.6120 1.6385 1.6632 1.6862 1.7082 1.7493 1.7872 1.8225
289.9 2.09 2.28 12.45 12.62 12.78 2.94 3.10 3.40
3.40 3.69
3.69 3.98
h 1199.61232.2 1259.6 1285.2 1310.3 1335.1 1359.8 1408.8 1457.7 1506.8
n 1.5379 1.5753 1.6049 1.6312 1.6558 1.6787 1.7005 1.7415 1.7792 1.8145
397.4 v 1.92 2.09 2.26 2.42 12.57 2.71 2.85 13.13 3.40 13.67
h 1200.9 1234:3 1261.9 1287.6 1312.8 1337.6 1362.3 1411.5 1460.5 1509.8
n 1.5309 1.5690 1.5985 1.6246 1.6492 1.6720 1.6937 1.7344 1.7721 1.8072
404.5 v 1.78 1.94 2.10 2.24 2.39 2.52 2.65 2.91 3.16 3.41
h 1202.11236.4 1264.1 1289.9 1315.1 1340.01364.7 1414.0 1463.2 1512.5
n 1.5244|1.5631 1.5926|1.6186 1.6430 1.6658 1.6874 1.7280 1.7655 1.8005
Steam
55
Press.
Abs.
Lbs.
per
Sq. In.
280
300
350
400
450
500
Temp.
Sat.
Steam.
Properties of Superheated Steam-Continued

0
50
Lb. per sq. in.
Temp. sat. °F.
100
Degrees of Superbeat.


°F °C.
212 100 0.463
302 150 .462 0.478 0.515
392 200
482 250
572 300
662 350
752
400
150 200
Volume of Superheated Steam-Linde's equation (1905),
(150,300,000
T3
250 300 400
411.2 v 1.66 1.81 1.95 2.09 2.22 12.35 2.48 2.72 2.95 3.19
h 1203.11238.4 1266.2 1291.91317.21342.21367.0 1416.4 1465.7 1515.1
n 1.5185 1.5580 1.5873 1.6133 1.6375 1.6603 1.68181.7223 1.7597 1.7945
417.5 v 1.55 1.69 1.83 1.96 2.09 2.21 2.33 2.55 2.77 2.99
h 1204.11240.3 1268.2 1294.0 1319.3 1344.3 1369.2 1418.6 1468.0 1517.6
n 1.5129 1.5530 1.5824 1.6082 1.6323 1.6550 1.6765 1.7168 1.7541 1.7889
431.9 y 1.33 1.46 1.58 1.70 1.81 1.92 2.02 2.22 2.41 2.60
h 1206.1 1244.6 1272.7 1298.7/1324.1 1349.3 1374.3 1424.0 1473.7 1523.5
n 1.5002 1.5423 1.5715 1.5971 1.6210 1.6436 1.6650 1.7052 1.7422 1.7767
444.8 v 1.17 1.28 1.40 1.50 1.60 1.70 1.79 1.97 2.14 2.30
h 1207.7 1248.6 1276.9 1303.01328:6 1353.91379.11429.01478.9 1528.9
n 1.4894 1.5336 1.5625 1.5880 1.6117 1.6342 1.6554 1.6955 1.7323 1.7666
456.5 v 1.04 1.14 1.25 1.35 1.44 1.53 1.61 1.77 1.93 2.07
h 1209 1252 1281 1307 1333 1358 1383 1434 1484 1534.0
n 1.479 1.526 1.554 1.580 1.603 1.626 1.647 1.687 1.723 1.758
467.3 v 0.93 1.03 1.13 1.22 1.31 1.39 1.47 1.62 1.76 1.89
h 1210 1256 1285 1311 1337 1362 1388 1438 1489 1539
In 1.470 1.519 1.548 1.573 1.597 1.619 1.640 1.679 1.715 1.750
462 .475
463 474
.464 475
468 .477
.4731 481 494 .504
pv=0.5962T-p(1+0:0014p)
-0.0833)
in which p, is in lb. per sq. in., v, is in cu. ft. and T, is the absolute temperature on the Fahren
heit scale, has been used in the computation of Marks & Davis' steam tables.
Specific heat of superheated steam.-Mean specific heats from the temperature of sat
uration to various temperatures at several pressures-Knoblauch and Jakob (from Peabody's
Tables).
500
14.2 28.4 56.9 85.3 113.3 142.2 170.6 199.1 227.5 256.0 284.4
248 289 316 336 350 368 381 392 403 412
210
.502 0.530 0.560 0.597 0.635 0.677
495 .514 .532
492 .505 .517
492 .503 512
.552,570
530 541
.512
.522 .529
.520 526
•
600


588 0.609 0.635 0.664
.550 .561 .572 .585
536 .543 .550 .557
.537 542 .547
.531
56
Steam

Temperature
Fahrenheit.
KERT FREER ZX888 JJRBH 8 Feed Water.
Degr's
80
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
200
205
210
212
0
5.
Factors of Evaporation
PRESSURE IN POUNDS PER SQUARE INCH ABOVE THE ATMOSPHERE,
15. 25.
35. 45. 55. 65. 75. 85. 95.
105.❘ 115. 125.
135. | 145.
155.
165.❘ 175. 185.❘ 200.
Temperature
Fahrenheit.
2727 SEARS BOZEZ õugag JZRBA ZAAHKÄ Feed Water.
Degr's
32
1.187 1.192 | 1.199 | 1.2041.209 1.212 | 1.216 | 1.218 1.221 1.223 | 1.226 | 1.228 1.230 | 1.231 | 1.233 1.235 | 1.236 1.238 | 1.239 | 1.240 1.241
1.184 1.1891.1961.2011.206 1.209 | 1.213 | 1.215 | 1.218 | 1.220 | 1.223 | 1.225 | 1.227 | 1.228 | 1.230 | 1.232 1.233|1.235 | 1.236 | 1.237 | 1.238
1.179 | 1.181 | 1.191 | 1.196 | 1.201 | 1.204 | 1.208 | 1.219 1.213 | 1.215 1.218 | 1.220 | 1,222 | 1.233 | 1.225 | 1.227 | 1,228 1.230 | 1.231 | 1.232 1.233
1.173 1.178 | 1.185 | 1.190 | 1.195 | 1.198 | 1.202 | 1.204 | 1.207 | 1.209 | 1.212 | 1.214 | 1.216 | 1,217 | 1.219 | 1.221 | 1.222 | 1.224 | 1.225 | 1.226 | 1.227
| | | | | | |
| | | | | | | |
1.168 1.173 1.180 1.185 1.190 1.193 1.197 1.199 1.202 1.204 1.207 1.209 1.211 1.212 1.214 1.216 1.217 1.219 1.220 1.221 1.222
1.163 1.168 1.175 1.180 1.185 1.188 1.192 1.194 1.197 1.199 1.202 1 204 1.206 1.207 1.209 1.211 1.212 | 1.214 1.215 1.216 1.217
1.158 1.163 | 1.170 | 1.175 | 1.180 1.183 1.187 | 1.189 | 1.192 | 1.194 | 1.197 1.199 | 1.201 | 1.202 | 1.204 | 1.206 1.207 1:209 1.2101.211| 1.212
1.153 1.158 | 1.165 | 1.170 | 1.175 | 1.178 | 1.182 | 1.184 | 1.1871.1891.192 | 1.194 1.196 1.1971.1991.2011.202 | 1.204 | 1.205 | 1.206 | 1.207
1.148 1.153 1.160 1.165 1.170 1.173 1.177 1.179 1.182 1.184 1.187 1.189 | 1.191 | 1.192 1.194 1.196 1.197 1.199 1.200 1.201 | 1.202
1.143 1.148 | 1.155 | 1.160 | 1.165 | 1.168 | 1.172 | 1 174 | 1.177 | 1.179 1.182 1.184 | 1.186 | 1.187 | 1.189 | 1.191 | 1.1921.194.195 | 1.196 | 1.197
1.176 | 1.178 | 1.180 | 1.181 | 1.183 | 1.185 | 1.186 1.188 1.189 | 1.190 | 1.191
90
130
1.124 | 1.126 | 1.128
1.137 | 1.142 | 1.149 | 1.154 | 1.159 | 1.162 | 1.166 1.168 1.171 1.173
1.132 1.137 1.144 1.149 1.154 | 1.157 | 1.161 | 1.163 | 1.166 1.168 1.171 | 1.173 | 1.175 | 1.176 1.178 | 1.180 | 1.181 | 1.183 1.1841.185 1.186
1.1271.132 1.139 1.144 | 1.149 | 1.152 | 1.156 1.158 1.1611.163| 1.166 | 1.168 | 1.170 | 1.171 | 1,173 | 1.175 1.176 1.178 1.179 | 1.180 | 1.181
1.122 1.127 | 1..34 | 1.139 1.144 1.147 1.151 1.153 | 1.156 1.158 1.161 1.163 | 1.165 | 1.166| 1.168 | 1.170 | 1.171 | 1.173 ¦ 1.174 | 1.175 1.176 95
1.117 1.122 1.129 | 1.134 | 1.139 | 1.142 | 1.146 | 1.148 | 1.151 | 1.153 | 1.156 1.158 1.160 1.1611.163 | 1.165 1.166 1.168 1.169 1.170 1.171 100
1.111 1.116 | 1.123 | 1.128 | 1.133 | 1.136 | 1.140 | 1.142 | 1.145 1.147 1.150 1.152 1.154 1.155 1.157 1.159 1.160 1.162 1.163 1.164 1.165 105
1.106 | 1.111 | 1.118 | 1.123 1.1281.131 1.135 1.137 | 1.140 | 1.142 1.145 1.147 1.149 1.150 1.152 | 1.154 1.155 | 1.157 | 1.158 | 1.159 1.160
110
1.101 1.106 1.113 1.118 | 1.123 | 1.126 | 1.130 1.132 1.135 1.137 | 1.140 † 1.142 1.144 1.145, 1.147 | 1.149 1.150 1.152 1.153 1.154 1.155
1.096 1.101 | 1.108 | 1.113 | 1.118 | 1.121 | 1.125 | 1.127 | 1.130 | 1.132 | 1.135 | 1.137 1.139 | 1.140 | 1.142 | 1.144 | 1.145 | 1.147 | 1.148 1.149 1.150
1.091 | 1.096 | 1.103 | 1.108 | 1.113 | 1.116 | 1.120 | 1.122 | 1.125 | 1.127 | 1.130 | 1.132 | 1.134 | 1.135 | 1.137 | 1.139 | 1.140 | 1.142 | 1.143 | 1.144 | 1.145
1.085 1.090 1.097 1.102 | 1.107 | 1.110 | 1.114 | 1.116 1.119 | 1.121 | 1.1241.126 1.128 1.1291.131 1.133 1.134 1:136 1.137 1.138 1.139
1.080 1.085 1.092 1.097 | 1.102 | 1.105 | 1.109 1.111 1.114 1.116| 1.119 | 1.121 1.123
1.129 1.131 1.132 1.133 | 1.134 135
1.075 | 1.080 | 1.087 | 1.092 | 1.097 | 1.100 | 1.104 | 1.106 | 1.109 | 1.111 | 1.114 | 1.116 | 1.118 | 1.119 | 1.121 |†1.123 1.124 1.126 1.127 1.128 | 1.129
140
1.070 | 1.075 | 1.082 | 1.087 | 1.092 | 1.095 | 1:099 | 1.101 | 1.104 | 1.106 | 1.109 | 1.111 1.113 | 1.114 | 1.116 | 1.118 1.119 1.121.1.122 | 1.123 | 1.124 145
1.065 | 1.070 | 1.077 | 1.082 | 1.087 | 1.090 | 1.091 | 1.096 | 1.099 | 1.101 1.101 1.106 1.108 | 1,109 | 1.111 | 1.113 | 1.114 | 1.116 | 1.117 1.118 1.119 150
1.059 1.064 | 1.071 1.076 | 1.081 | 1.084 1.088 | 1.090 | 1.094 1.095 1.098 1.100 1.102 | 1.103 | 1.1051.107 | 1.108 1.110 1.111 1.112 1.113
1.054 1.059 1.066 | 1.071 1.076 1.079 | 1.083 | 1.085 1.088 1.090 1.093 1.095 | 1.C97 | 1.098 1.100 1.102 1.103 1.105 1.106 1.1071.108
1.049 1.054 1.061 | 1.066 | 1.071 | 1.074 | 1.078 1.080 | 1.083 | 1.085 | 1.088 | 1.090 | 1.092 | 1.093 | 1.095 | 1.097 1.0981.100 | 1.101 | 1.102 | 1.103
1.044 1.049 1.058 1.061 1.060 1.069 1.073 1.075 1.078 | 1.080 1.083 1.085 | 1.087 | 1.088 1.090 1.092 | 1.093 1.095 1.096 1.097 1.098
1.039 1.044 | 1.051 1.056 1.0611.064 1.068 1.070 | 1.073 1.075 1.07C 1.080 1.082 1.083 1.085 1.087 1.088 1.090 1.091 1.0921.093
| | |
1.033 1.038 1.045 1.050 1.055 1.058 1.062 1.064 1.067 1.069 1.072 1.074 1.076 1.077 1.079 1.081 1.082 1.084 1.085 1.086 1,087
1.028 1.033 | 1.040 | 1.045 | 1.050 | 1.053 | 1.057 | 1.059 | 1.062 | 1.064 | 1.067 | 1.069 | 1.071 | 1.073 | 1.074 | 1.070 | 1.077 | 1.079 | 1.080 | 1.081 | 1.082
1.023 1.028 1.035 1.040 1:045 1.048 1.052 1,054 | 1.057 | 1.059 1.062 1.064 1.066 1.067 | 1.069 1.071 1.072 | 1.074 1.075 1.076 1.077
1.018 1.023 | 1.030 | 1.035 | 1.040 | 1.043 | 1.047 1.049 1.052 | 1.054 | 1.057 | 1.059 | 1.061 1.062 1.064 1.066 1.006 | 1.069 1.070 1,071 1.072
1.013 1.018 1.025 1.030 1.0351.038 1.042 1.044 1.047 1.049 1.052 1.054 1.056 1.057 1.059 1.061 1.062 1.064, 1.065 1.066 1.067-
1.001 1 012 1.019 1.024 1.029 1.032 1.036 1.038 1.041 1.043 1.046 1.048 1.050 1.051 1.053 1.055 1.056 1058 1.059 1.060 1.062
| | |
1.0021 007 1.014 1.019 1.024 1.027 1.031 1.033 1.036 1.038 1.041 1.043 1.045 1.046 1.048 1.050 1,051 1.053 1.051 1.055 1.057
1.000 1.005 1.012 3.017 1.022 1.025 1.029 1.031. 1.034 1.0361.039 1,041 1.043 1.044 1.046 1.048 1.049 1.051 1.052 1.053 1.056
55
75
80
85
115
120
125
155
160
165
170
175
180
185
190
195
200
205
210
212
Steam
57
1
2
Factors of Evaporation.-It takes more coal to generate
steam at high pressure than at low pressures, and accordingly
in the rating of steam boilers some standard of evaporation must
be adopted in order to obtain a true measure of performance.
This involves two items.
Temperature of the feed water;
Pressure at which the steam is generated.
With respect to the first item, it must be evident that more coal would
be used in generating steam if the feed water were supplied at a low tem-
perature, say 60° F, than at a higher temperature, say 150° F. and no
comparison of the performance of two boilers working under these con-
ditions could be obtained, unless a factor were introduced in the calculation
to allow for the difference in temperature of the feed water. The reason
more heat is required as the pressure of the steam is raised may be less
apparent.
Ques. Why is more coal required to generate steam at
a high pressure than at a low pressure?
Ans The external work of vaporization is greater
That is to say, more work is done in the formation of the steam in making
room for itself against a high pressure than against a low pressure.
Ques. How is a standard of vaporization obtained?
Ans. By finding the equivalent vaporization "from and at
212° Fahr "
Ques. What is the meaning of the term "from and at
212° Fahr.?”
Ans It signifies the generation of steam at 212° F from
water at the same temperature
Ques. Define the term "factor of evaporation.
Ans. A factor of evaporation is a quantity which when multi-
plied by the amount of steam generated at a given pressure from
58
Steam
water at a given temperature, gives the equivalent evaporation from
and at 212° Fahr
Ques. How is the factor of evaporation obtained?
Ans. It is equal to the difference in the heat in the steam at
the pressure generated, and the heat in the water divided by the
latent heat of steam at atmospheric pressure.
That is, factor of evaporation
in which
Expressed as a formula:
F=
F = Factor of Evaporation.
H = Heat above 32° Fahr. in the steam at given pressure.
h = Heat above 32° Fahr. in water at given pressure.
H=Heat above 32° Fahr. in steam at atmospheric pressure.
h" =Heat above 32° Fahr. in water at atmospheric pressure.
H-h
H'-h'
F:
latent heat at generated pressure
latent heat at atmospheric pressure
Formula (1) just given is expressed in the simplest form as
H-h
970.4
(1)
1,199.2-118
970.4
(2)
Here 970.4-H' -h'
1150.4-180 (see steam table)
Example-What is the factor of evaporation for steam at 200 pounds
pressure when the feed water is delivered to the boiler at a temperature of
150° Fahr? From the steam table, the heat H, in the steam at 200 pounds
pressure = 1,199.2 B.t.u. The heat h, in the feed water above 32° at 150°
Fahr is 150-32=118 B.t.u Substituting these values in formula 2
F=
=: 1.1142
The meaning of it is that if a boiler were generating, say 1,000 pounds of
steam per hour at 200 pounds pressure, from feed water at 150° Fahr. it
would absorb the same amount of heat from the fire as when generating
1,000X1,1121=1,112 lbs.
of steam "from and at 212°", that is generating steam at atmospheric
pressure from feed water at 212.
Heat
59
HEAT
TOOL
REST
CHAPTER 5
What is heat?
Ans. A form of energy in bodies consisting of molecular
vibration.
Heat
FRICTION
WORK

EMERY WHEEL
Fig. 1.-Grinding tool on emery wheel illustrating heat due to friction.
What governs the degree of molecular vibration?
Ans. The higher the temperature, the faster the molecules
move; the lower the temperature, the slower they move.
What is the unit of heat?
Ans. The British thermal unit (B.t.u.) as previously ex-
plained.
60
Heat
Temperature
A substance is said to be hot or cold according to its physical
or sensible effect when touched.
Define temperature?
Ans. Temperature is that condition of a body on which its
power of communicating heat to or receiving heat from other
bodies, depend.
ACTUAL IN PRACTICE
(cu
CURVES EXAGGERATED
FOR EMPHASIS

tve
ど
​ť
ISOTHERMAL
ADIABATIC
LOSS SAVED
(SOLID BLACK)
LOSS NOT SAVED
(IN SECTION)
Fig. 2.-Isothermal, adiabatic and actual compression curves showing position
of the loss due to the heat of compression not saved and saved.
When is a body at a higher temperature than another
body?
Ans. When its molecules move faster than those of the other
body.
How is temperature measured?
Heat
61
Ans. Ordinary temperatures by a thermometer. Very high
temperatures in a combustion chamber, by a pyrometer.
What is the basic principle of thermometers?
Ans: Expansion and contraction of substances due to the
effect of heat.
What are the two fixed points on the thermometer scale?
Ans. The freezing point and the boiling point (at standard
atmospheric pressure).
How is the scale graduated?
Ans. By graduating the distance between the two fixed
points into the proper number of degrees corresponding to the
particular scale used.
What are the scales in general use and where used?
Ans. The Fahrenheit (in English speaking countries); the
Centigrade or Celsius (in countries that use the metric system);
and the Reaumur (used on the continent of Europe).
=
The Fahrenheit Scale.-The number of degrees between the two
fixed points is 180. The freezing point is 32° above zero, hence the boil-
ing point is 32° +180° 212°.
The Centigrade Scale.-The number of degrees between the two
fixed points is 100. The freezing point is zero, hence the boiling point
is 100°.
The Reaumur Scale.-The number of degrees between the two
fixed points is 80. The freezing point is zero, and accordingly, the boil-
ing point, 80°.
Comparison of Thermometer Scales
The following conversion factors will be found convenient in
obtaining equivalent readings on the different scales.
6.2
Heat
1
1 degree Fahrenheit
Centigrade
Reaumur
1
"
COLD
Temperature Fahrenheit
44
Centigrade
Reaumur
one type metal
=
another type metal
=
JUNCTION
Heated end
-
5/9 degree Centigrade
Fahrenheit =
44
9/5
9/4
44
=
*********
ICE
....
44
protective case
4/9 degree Reaumur
"
4/5
40
5/4
9/5 X temp. C + 32°
5/9 × (temp. Fahr.
4/5 temp. C = 4/9 (Fahr.
32)
"/li\
Figs. 3 and 4.-Two familiar examples of sensible heat.
Cold
end
9/4 R + 32°
5/4 R
- 32)
HOT
HOT
qatla
"
=
Centigrade



Wires to
milli-voltmeter

MILLI-VOLTMETER
graduated to read
degrees of heat
Fig. 5.-Elementary thermocouple thermometer used for measuring high tem-
peratures. In principle, when heat is applied to the junction of two dissimilar
metals, a current of electricity begins to flow in proportion to the amount of
heat applied; this current can be brought to a meter and translated into terms
of heat. The thermocouple for Diesel engine use is inserted in an opening in
the cylinder exhaust and, by its temperature reading, denotes the burning con-
dition of the fuel; by it, also, it is possible to compare the actions in the various
cylinders. Where thermocouples are permanently installed in cylinder exhausts,
the individual thermocouples may be connected to one indicating instrument
by switches which connect one or another at will, for comparative readings.
Heat
63
180 DIVISIONS
212 BOILING POINT
200
190
180
170
160
150
140
130
120
110
100
90
80
70
60
50
320FREEZING
25
20
THERMOMETER SCALES


10
0°
-100 DIVISIONS-
--
OOF WATER
90
8 8 8 8 ☀ %
20
10
-0° POINT OF
MERCURY FILLED BULBS
CENTIGRADE
80 DIVISIONS-
80°
-70
888
60
50
40
-30
20
10
WATER
FAHRENHEIT
REAUMUR
Fig. 6.-Fahrenheit, Centrigrade and Reaumur thermometer scales.
64
Heat
i
What is a pyrometer?
Ans. An instrument for measuring very high temperatures.
What are the principles of operation of the various types?
Ans. Various principles have been employed as: 1, contrac-
tion of clay by heat; 2, relative expansion of two dissimilar
metals; 3, thermo-electric couple, etc.
High Temperature Judged by Color
High temperatures may be approximated by the experienced
eye. The following table by Pouillet is generally accepted,
giving colors and the corresponding temperatures.
Incipient red heat . .
Dull red heat..
•
Incipient, cherry red
heat.
•
Temperature Colors
Deg. Deg.
с
F
525
977
700 1,292
800 1,472
900 1,652
Cherry red heat..
Clear cherry red heat 1,000 1,832
Deep orange heat..
Clear orange heat..
White heat..
Bright white heat..
Deg. Deg.
с
F
1,100 2,021
1,200 2,192
1,300 2,372
1,400 2,552
(1,500 2,732
to
Dazzling white heat< to
1,600 2,912
Expansion Due to Heat
The amount by which say, a metal rod increases in length
for a rise of temperature differs for different metals - this is
linear expansion.
Heat
65

O
سلسلسسلسله
200109
Thumhu
06
80
09
40 150
30
10 20
001
mmmm.lumamulumiiniumininkus.
90
08
70
09 05
A0
44.
Define the coefficient of
linear expansion.
Ans. It is: The ratio of the in-
crease in length produced by a
rise of temperature of 1° to the
original length.
What provision must be
made in boilers because of
the expansion of the metal
due to the heat?
Ans. In setting horizontal
shell boilers by the old method,
one end is supported on rollers.
Old methods are shown in figs.
12 and 13. A better method is
shown in fig. 14.

What provision is made in
water tube boilers?
Ans. The tubes are arranged
so that they are free to expand
and contract.
Figs. 7 and 8.-Tagliabue mercury well temporary thermometer connection
and type of thermometer used with same. The mercury well is designed for use
with a solid glass thermometer (fig. 7) for test work or for application where only
an occasional reading is required. There is a seating plug provided with a gas-
ket for confining the mercury.
66
Heat
Give an advantage of expansion and contraction by heat.
Ans. Boiler plates are fastened by red hot rivets.
When the rivets cool they contract and bind the plates together
with great force.

THERMOMETER
CRACKED
ICE
BAF
Plan
ນາງ
44.0.424/
**}}}|
WAKITT
Wash
Fig. 9.-Method of determining the freezing point. some ice, break it
small and pack it around the bulb of the thermometer in a glass or metal funnel
so that the water which forms as the ice melts may drain away into a vesse
placed below to receive it. The ice should be heaped up around the tube until
only the top of the column is visible, and the thermometer left thus covered for
15 minutes. Then, with a fine file, make a scratch on the glass opposite to the
top of the column of mercury which represents the freezing point.
Heat
67
Give a disadvantage of expansion and contraction by
heat.
WATER RESISTANT TO RE
Ans. A short space must be left between the rails of a rail-
road to permit this expansion and contraction.

•
-
OC
O
O O C
K
p=
FAHR
C
THE AND MAY HERE THAT T
LUG
A
FAHR
ANITATIONS ARE MANAGED AND WANTED MEDIA
F
COEFFICIENT OF EXPANSION = F÷L
Figs. 10 and 11.-Coefficient of expansion. If a bar of length L at temperature
n° Fahr., as in fig. 10, be heated to n° + 1° Fahr., and expand a distance F,
as in fig. 11, then the coefficient of expansion is F÷L.
ROLLER
PLATE
LL.

Fig. 12.-The usual but objectionable method of providing for expansion on
Tug supported boilers. It will be seen that no provision is made for transverse
expansion of the shell, consequently the side walls must "breathe" with the
boiler, which tends to produce air leaks by cracking and loosening the mortar.
i
68
Heat
Transfer of Heat
How is heat transferred from one body to another at
lower temperature?
Ans. By 1, radiation; 2, conduction; and 3, convection.
Describe radiation, conduction and convection in boiler
operation.

O OO
OO O
OOOO
ROLLERS
PLATES
Fig. 13.-Approved method of providing for expansion on lug supported boilers.
The two sets of rollers placed at right angles to each other form a universal
joint, allowing free movement both endwise or crosswise.
Ans. Heat from the burning fuel passes to the metal of the
heating surface by radiation; through the metal by conduction;
and is transferred to the water by convection (circulation).
What is conductivity?
Ans. The relative value of a material, as compared with a
standard, in affording a passage through itself or over its surface
for heat. See fig. 16.
What is a very bad conductor ignorantly called?
Ans. A non-conductor.
Heat
69
Name a good conductor.
Ans. Copper.
Any substance that is a good conductor of electricity is a good
conductor of heat.

oooooooooooo
ос
OOOOOO 00000
ооо о OOOO
Oo
о
Fig. 14.-Method of providing for expansion by link suspension. As may be
seen, the weight of the boiler is carried by the steel work, thus relieving the
brick work of this duty. The side columns may be either of solid channel iron
or built up from angles and lattice work, and channel bars are carried across
the top of these columns as shown. The boiler is suspended from these channels.
by suspension links or rods arranged with nuts and washers, permitting easy
leveling and adjustment of the height of the boiler.
Specific Heat
By definition the specific heat of a substance is: The ratio of
the quantity of heat required to raise its temperature one degree to
the amount required to raise the temperature of the same weight
of water one degree.
70
Heat
Expressed as a formula:
Specific heat
=
MAPOROROCHIM AHOLAHRAMANH
B.t.u. to raise temp. of substance 1°
B.t.u. to raise temp. of same weight water 1°
from this it follows:
Specific heat =B.t.u. required to heat 1 lb. of a substance 1° Fahr.

RADIATION
CONDUCTION
€9
DAMIAMUTHAMARAMIHAD
CONVECTION
PUMP
CONVECTION
B.
Fig. 15.-Elementary diagram illustrating transfer of heat by radiation, con-
duction and convection. It should be noted that air is the cooling agent
and not the water as the water is only the medium for transferring the heat
to the point where it is extracted and dissipated by the air. Accordingly, the
term water cooled engine is,a, misnomer, but nothing can be done about it.
What is the standard?
Ans. Water usually from 62° to 63° Fahr.
Example.-The same quantity of heat that will raise 1 lb. of water
1° Fahr. will raise about 8.4 lbs. of cast iron 1° Fahr. Accordingly the
specific heat of water being taken as 1, that of cast iron would be only
1 ÷ 8.4 .119
That is, it is the ratio between the two heats.
Heat
71

WIRES
TWISTED
BUNSEN
BURNER
(G.SILVER)
Copper.
Wrought iron.
Glass....
Cast iron.
Lead..
Tin..
Steel {Hard.
Brass..
Ice...
IGNITION
(IRON)
(COPPER)
MATCHES
Fig. 16.-Experiment illustrating heat conductivity of various metals.
Specific Heat of Various Substances
Solids
COPPER
IRON
GERMAN SILVER
HEAT TRANSFER DISTANCES
•
.0951
.1138
.1937
.1298
.0314
.0562
.1165
1175
.0939
.504
72
Heat
་
Water..
Sulphuric Acid..
Mercury
Alcohol
Benzine
Ether...
Air....
Oxygen.
Hydrogen..
Nitrogen.
Ammonia.
Alcohol...
Liquids
Gases
•
.23751
.21751
3.409
.2438
.508
.4534
1.
Constant Constant
pressure
volume
.335
.0333
.7
.95
.5034
.16847
.15507
2.41226
.17273
.299
.399
Fuels
73
CHAPTER 6
Fuels
Define the term fuel.
Ans. A fuel is any substance which will by burning (rapid
oxidation) produce heat and light as coal, wood, oil, gas, etc.
What are the chemical constituents of coal?
Ans. Carbon, hydrogen, oxygen, nitrogen, and inorganic mat-
ter that constitutes the ash. Sulphur in the free state is some-
times present in coal.
Explain the terms volatile matter, fixed carbon, total
combustible, and ash?
Ans. In the language of the chemist, that part of coal,
moisture excepted, which is driven off when a sample is sub-
jected to a temperature up to about 1,750° F. is the volatile
matter; the solid carbon is the fixed carbon; the sum of volatile
matter and fixed carbon is the total combustible, and the part
that does not burn is ash.
What causes the different heating values of the mining
grades of coal?
Ans. The varying quantities of the chemical constituents
and their combinations.
74
Fuels
How are fuels broadly classed?
Ans. 1, solid; 2, liquid; and 3, gaseous.
Solid Fuels
What is the effect of sizes of lumps of coal?
Ans. In general the smaller the size, the greater the amount
of impurities present, the heat value is lower, more coal sifts
through the grate and other objectionable results are increased.
Class
Classification of American Coals

Sub-bituminous and lignite..
Bituminous, low grade…….
Bituminous, medium grade.
Anthracite..
Semi-anthracite..
Bituminous, high grade.
Semi-bituminous.
Eadern cannel....
•
•
··
Volatile
matter
in % of
com-
bustible
27 to 60
32 to 50
32 to 50
less than 10
10 to 15
30 to 45
15 to 30
45 to 60
Oxygen
in com-
bustible
%
10 to 33
7 to 14
6 to 14
1 to 4
1 to 5
5 to 14
1 to
5 to
6
8
B.t.u. per
pounds of
combustible
9,600 to 13,250
12,400 to 14,600
13,800 to 15,100
14,800 to 15,400
15,400 to 15,500
14,800 to 15,600
15,400 to 16,050
15,700 to 16,200
What is the consequence of this?
Ans. The larger sizes usually command higher prices, espe-
cially for anthracite.
How is coal graded as to sizes?
Ans. By screening through standard openings which, how-
ever differ somewhat both in size and shape in different locali-
ties. The following table gives names and corresponding sizes.
This does not relate to pulverized coal, blowing into the furnace by
air blast.
Fuels
75
Broken...
Egg.
Stove..
Chestnut.
..
•
Pea..
No. 1 Buckwheat..
No. 2 Buckwheat.
No. 3 Buckwheat.
Culm...
• •
Sizes of Anthracite Coal
Size
•
Diameter of opening
through or over which coal
will pass, inches
Through
41/2
31/4
25/16
15%
7/2
9
5
8
16
3/16
3/32
Name two general divisions of coal.
Ans. Hard or anthracite, and soft or bituminous.
Over
314
25/16
15%
7/8
9/16
3/16
5/16
3/12
What is the heating value of coal?
Ans. Approximately: Anthracite 14,000 to 15,000 B.t.u.;
bituminous, 12,000 to 15,000 B.t.u.
What is coke?
Ans. The solid substance remaining after the partial burning
of coal in an oven or after distillation in a retort.
How is gas retort coke produced?
Ans. By the application of high temperature to the outside
of the retort for a short time.
What are its principal uses?
Ans. For domestic purposes and sometimes in steam boiler
practice.
76
Fuels
What is the heating value of coke?
Ans. Roughly about 14,000 B.t.u.
What is peat?
Ans. A substance of vegetable origin always found more or
less saturated with water in swamps and bogs.
It consists of roots and fibres in every stage of decomposition from
the natural wood to vegetable mold.
What must be done to use peat as a fuel?
Ans. It must be dried out as much as possible.
How is peat prepared as a fuel?
Ans. As: 1, hand or spade peat; 2, briquetted peat; 3, ma-
chine peat.
What is the heating value of peat?
Ans. About 9,000 to 10,000 B.t.u.
As a fuel what is included in the term wood?
Ans. It designates the limbs and trunks of trees as they are
felled.
Name two general classes of wood?
Ans. 1, hard; and 2, soft.
What is the effect of moisture in wood?
Ans. It causes a loss of economy.
What is the heating value of wood?
Ans. Roughly, dry wood 7,800 B.t.u.; ordinary fire wood
5,800 B.t.u.
Fuels
77
What is the relative heating value of wood as compared
with coal?
Ans. The heating value of thoroughly dried wood is about
40 per cent that of coal.
What kind of tan bark is generally used as a fuel?
Ans. Oak bark.
How is wet tan bark successfully burned?
Ans. By burning it in a furnace of sufficient volume to
accommodate a large quantity of wet bark exposed to the
heated gases coming from the burning bark, which has been
previously dried.
What is the heating value of bark in its oridnary state?
Ans. Bark containing 30 per cent of water has a heating value
of about 4,000 B.t.u.
Is straw used for fuel?
Ans. It is in certain locations.
What is the basic requirement for burning straw?
Ans. It must be fed into the furnace only as fast as consumed.
What are the conditions for burning saw dust?
Ans. Ample room should be given it in the furnace and
sufficient air supplied on the surface of the mass.
What is the heating value of saw dust?
Ans. Roughly 4,000 to 6,000 B.t.u. depending upon its com-
position and condition.
78
Fuels
What is bagasse?
Ans. The fibrous portion of sugar cane left after the juice
has been extracted.
Of what does bagasse consist?
Ans. Woody fibre, water, sucrose, glucose and other solids
in varying proportions, depending upon the quality of the
cane and its treatment in the mill.
What is the heating value of bagasse?
Ans. Its average heating value when dry is 8,360 B.t.u.
What is the value of tar as a fuel?
Ans. It is usually much lower than its value for other
purposes.
How does the yield of tar vary?
Ans. It varies with the kind of coal and with the methods
employed from about 4½ to 62 per cent of the weight of coal.
What is the heating value of tar?
Ans. A series of calorimetric tests give about 15,700 B.t.u.
Liquid Fuels
In general, of what does crude oil consist?
Ans. It consists of carbon and hydrogen, though it also con-
tains varying quantities of moisture, sulphur, nitrogen, arsenic,
phosphorous and silt.
Fuels
79
What is the percentage of moisture?
Ans. From 1 to over 30 per cent.
What is the heating value of petroleum?
Ans. From 18,000 to 22,000 B.t.u. approximately.
What are the relative values of oil and coal as fuels?
Ans. Under favorable conditions 1 lb. of oil will evaporate
from 14 to 16 lbs. of water from and at 212° Fahr.; 1 lb. of coal
will evaporate from 7 to 10 lbs. of water from and at 212° Fahr.
Gaseous Fuels
What kinds of gaseous fuels are used in steam boilers?
Ans. Natural gas, waste gas from blast furnaces, coke oven
gas and producer gas.
How do gas fuels compare with liquid fuels?
Ans. Gas fuels offer all the advantages of liquid fuels and
but few of the disadvantages.
What is the heating value of a natural gas?
Ans. It varies from 800 to 1,100 B.t.u. per cu. ft.
What is the relative value of natural gas as compared to
coal?
Ans. 1,000 cu. ft. of natural gas is approximately equivalent
to 57.25 lbs. of coal.
80
Fuels
Comparative Evaporation of Coal and Oil
Taken from the United States Geographical Report on Petroleum
One Pound of Combustible
Petroleum 18 to 40 deg. Baume..
Pittsburg lump and nut, Penna.
Pittsburg nut and slack, Penna….
Anthracite, Penna..
Indiana block..
Georges Creek lump, Maryland...
New River, West Virginia.
Pocahontas lump, West Virginia….
Cardiff lump, Wales..
Cape Breton, Canada..
Nanaimo, British Columbia.
Co-operative, British Columbia.
Greta, Washington..
Carbon Hill, Washington.
•
•
•
·
•
•
•
·
Barrels of Petro-
Pounds of Water leum required to
Evaporat's at 212 do same amount of
deg. per pound of evaporation
as
combustible
one ton of coal
10.
8.
9.8
9.5
10.
9.7
10.5
10.
9.2
7.3
8.9
7.6
7.6
Đó có có tin t
4.
3.2
288
3.9
3.8
4.
3.8
∞2
4.2
4.
3.7
2.9
3.6
3.
3.
Combustion
81
CHAPTER 7
Combustion
What is combustion?
Ans. Rapid oxidation.
What is oxidation?
Ans. The act of combining with oxygen, or subject to the
action of oxygen, or of an oxidizing agent.
What is this oxygen called?
Ans. The supporter of combustion.
Where is it obtained?
Ans. In the air.
How much oxygen is contained in the air?
Ans. 20.91 per cent by volume; 23.15 per cent by weight.
What is the material called which is capable of com-
bustion?
Ans. The combustible
In steam engineering practice the term combustible is applied to
that portion of the material which is dry and free from ash.
What is a fuel?
82
Combustion
Ans: Any material which serves by combustion for the pro-
duction of fire, as coal, coke, oil, etc.
Give another definition for combustible.
Ans. It is that portion of the fuel which burns.
What are the principle combustibles in coal and other
fuels?
Ans. Carbon, hydrogen and sulphur.



…………………………………||||||||||
………||||iminalRAT
་་་་་་
LETTER protoKKAVUULI
|||||||||
Figs. 1 and 2.-Principle of the Davy safety lamp: A flame will not pass
through wire gauze. The reason for this is that the gauze conducts the heat
away from the flame so rapidly that the gas on the other side is not raised to
the kindling point, that is to the temperature of ignition.
What is carbon?
Ans. A combustible element, non-metallic in its nature which
is present in most organic compounds.
As a combustible it forms the base of lamp black and charcoal and
enters largely into mineral coals.
How much carbon is contained in bituminous coal?
Ans. About 50 per cent.
Combustion
83
How is carbon obtained from wood?
Ans. It is separated from wood in the form of charcoal by
distilling off the more volatile elements.
What is hydrogen?
Ans. A colorless, odorless, tasteless gas, the lightest body
known.
!!///////
This element is combustible, burning with an almost invisible flame.
It is a non-supporter of combustion.

*•.F^Q^{\EX¶…(^[ANUELLER-HIEKKALAX
What is sulphur?
Ans. An elemen-
tary mineral sub-
stance of a yellow
color, brittle, insol-
uble in water, easily
fusible and inflam-
mable. It burns
with a blue flame and
gives off a peculiar
suffocating odor.
Why is the pres-
ence of sulphur in
fuel objectionable?
Fig. 3.-Experiment illustrating the cooling of flame below the igniting
temperature. With a wire coil placed as shown, the heat of the flame will
be transmitted along the wire so rapidly that the temperature will fall below
the point at which combustible gases combine with oxygen, that is, below the
kindling point, and here the flame will be extinguished. The cooling effect is
also illustrated in the operation of an internal fire box boiler where the heat
of the fuel lying next to the furnace walls is transmitted through the walls to
the water so rapidly that the fire becomes "dead" along the walls.
84
Combustion
Ans. It has a tendency to aid in the formation of clinkers,
and the gases from its combustion, when in the presence of
moisture, may cause corrosion.
What is the ignition or kindling point?
Ans. That temperature which will cause a combustible to
unite with oxygen and cause combustion to take place.
Describe what happens when combustion takes place.
Ans. The two principle elements of coal, carbon and hydrogen
have an affinity for oxygen. When they unite chemical heat is
produced. The oxygen having the stronger affinity for hydrogen
unites with it first and sets the carbon free. A multiplicity of
solid particles of carbon thus scattered in the midst of burning
hydrogen are raised to a state of incandescence.
The carbon in due time unites with the oxygen, forming carbon
dioxide or carbon monoxide.
What happens to the hydrogen during combustion?
Ans. The hydrogen unites with the oxygen in the proportion
of two atoms of hydrogen to one atom of oxygen forming
water (H2O).
Mention an important feature in the process of com-
bustion.
Ans. Chemical compounds are formed by the combination of
carbon and hydrogen.
What are these compounds called?
Ans. Hydro-carbons.
What are the most important hydro-carbons?
Ans. Methane or marsh gas, ethylene or olefiant gas, acet-
ylene and penzole.
Combustion
85
What are the products of complete combustion?
Ans. Carbon dioxide (CO2) and water (H2O).
What other names are given to carbon dioxide and
carbon monoxide?
Ans. Carbonic acid and carbonic oxide respectively.
When is combustion complete?
Ans. When the combustible unites with the greatest possible
amount of oxygen, as when one atom of carbon unites with
two atoms of oxygen to form carbon dioxide-CO2.
When is combustion incomplete and why?
Ans. When the combustible does not unite with the maxi-
mum amount of oxygen, as when one atom of carbon unites
with one atom of oxygen to form carbon monoxide (CO). The
reason is that the carbon monoxide (CO) may be further burned
to carbon dioxide (CO2).
What causes incomplete combustion?
Ans. Insufficient supply of air.
What happens when too little air is admitted to the fire?
Ans. There will not be enough oxygen present to supply two
atoms of oxygen to each atom of carbon liberated, hence carbon
monoxide will be formed having a heating value of 4,450 B.t.u.
instead of carbon dioxide which has a heating value of 14,500
B.t.u.
What results when too much air is supplied?
&
86
Combustion
Ans. Since carbon cannot combine with oxygen in any greater
ratio than two atoms of oxygen to one atom of carbon, any
excess air supply simply dilutes the gases and cools the furnace.
Are steam boilers usually operated with too much air
supply?
Ans. Yes, an excess supply as large as 150 per cent is not
uncommon. too much draught being as a rule employed.

BRIGHT WHITE LIGHT
ALMOST BLACK-
BLUE-
INVENT
m
OUTERMOST CONE OR MANTLE
PERFECT COMBUSTION
INTERMEDIATE CONE
IMPERFECT COMBUSTION
INNERMOST CONE
COMBUSTIBLE GAS
CUP
PERFECT COMBUSTION
Fig. 4. The candle flame. The form of the candle flame is common to all flames
which consist of gas issuing from a small circular jet, like the wick of a candle.
The gas issues from the jet in the form of a cylinder which, however, imme-
diately becomes a diverging cone by diffusing into the surrounding air. When
this cone is kindled, the margin of it, where interruption with the surrounding air
is nearly complete, will be perfectly burned, but the gases in the interior of the
diverging cone cannot burn until they have ascended sufficiently to meet with
fresh air; since these unburned gases are continually diminishing in quantity,
the successive circles of combustion must diminish in diameter resulting in the
conical shape.
Combustion
87
What is the effect of heating the air supply?
Ans. It increases the rate of combustion.
What are the objectionable effects of the nitrogen con-
tained in the air supply?
Ans. In passing through the furnace without change it dilutes
the air, absorbs heat, reduces the temperature of the product
for combustion, and is the chief source of heat losses in furnaces.
What is the useful effect of nitrogen?
Ans. It prevents too rapid combustion.
Without the large proportion of nitrogen in the atmosphere, the
latter would be so rich in oxygen, that the resulting high rate of
combustion would burn out the grates.
Is it possible in practice to obtain perfect combustion
with the theoretical amount of air?
Ans. No.
An excess is required, amounting to sometimes double the theoretical
supply, depending upon the nature of the fuel to be burned and the
method of burning it. The reason for this is that it is impossible to bring
each particle of oxygen in the air into intimate contact with the particles
in the fuel that are to be oxidized, due not only to the dilution of the
oxygen in the air by nitrogen, but because of such factors as the irreg-
ular thickness of the fire, the varying resistance to the passage of the
air through the fire in separate parts on account of ash, clinker, etc.
Is as large an excess of air required for oil as for coal?
Ans. No.
What is flame?
Ans. Visible flame is a combustible gas heated to an intense
heat. See fig. 4.
88
Combustion
What is the product of perfect combustion of carbon?
Ans. Invisible carbonic acid.
The product of perfect combustion of hydrogen is invisible water
vapor steam.
ddag
How is the state of the combustion in a furnace deter-
mined and why?
A

BO
с
Fig. 5.-Experiment with Davy's lamp. If the lamp be suspended in a large jar,
closed at the top with a perforated wooden cover A, and having an opening B,
below through which coal gas is allowed to pass slowly into the jar, the flame
will be seen to waver, to elongate very considerably, and finally to be ex-
tinguished, when the wire cage will be filled with a mixture of coal gas and
air burning tranquilly within the gauze which prevents the flame passing to
ignite the explosive atmosphere surrounding the lamp. As proof that the lamp
is surrounded by an explosive mixture, a lighted taper inserted through the
hole C, will cause an explosion.
Ans. It is determined accurately by determining the amount
of carbonic acid in the flue gases because carbon is the principle
constituent of the fuel.
What happens when fresh coal is fired into a hot furnace?
Ans. Incomplete combustion.
Combustion
68
CARBON MONOXIDE
(GAS BURNING)
CARBON MONOXIDE
(INCOMPLETE COMBUSTION)
CARBON MONOXIDE
C
c0tc2co
CO
CO
C
여
​CARBON DIOXIDE
(DOES NOT BURN)
CARBON MONOXIDE
-CARBON DIOXIDE
CARBON DIOXIDE
(COMPLETE COMBUSTION)
PRIMARY
AIR SUPPLY
CARBON DIOXIDE
co₁₂+0=co₂
CO
CO
2
SECONDARY
AIR SUPPLY
Figs. 6 and 7.-Combustion in an ordinary stove, illustrating incomplete and complete combustion.
What is the visible indication of incomplete combustion?
Ans, Smoke,

90
Combustion
What is smoke?
Ans. The term is applied to all the products of combustion
escaping from the furnace whether visible or invisible.
What are the black particles in smoke?
Ans. Solid carbon.

•
A
……………………………………………………
What does colored smoke indicate?
Ans. Incomplete combustion. See figs 6 and 7.
What is volatile matter?
CANCER, COO,
Fig. 8.-Experiment showing that combustion occurs only at the surface
of an ordinary flame. Insert one end of a small open tube into the
flame. The combustible gas will then escape at the other end and can be
lighted with a match.
Combustion
91
Ans. Substances that distill at low temperatures and are re-
leased when the coal is heated.
WRA
Upon the amount and nature of these distillates depend the amount.
and nature of the smoke produced.

CHIMNEY
BURNER
CARD
EI
·AIR SUPPLY
…………………
Fig. 9.-Cause of smoke. When the supply of oxygen is insufficient to con-
sume the particles of solid carbon, they are set free and then assume the form
of soot, the collection of these minute particles being called smoke.
Upon what does the smoke producing tendency of coals
depend?
Upon the nature rather than the volume of the volatile
content.
92
Combustion
What is the effect when the air supply does not thorough-
ly mix with the gases from the fuel?
Ans. It causes slower combustion resulting in a longer flame.
How can the hydro-carbon gases be completely and
smokelessly burned?
Ans. By admitting and thoroughly mixing sufficient air before
the gases are cooled below a certain temperature.

A
►
·
•
········
·····
Figs. 10 to 15.—Ringelmann scale for grading smoke density. It consists of
four large sheets ruled with vertical and horizontal lines forming squares as
shown. No. 1 is ruled with line 1 mm thick and spaced 9 mm wide; No. 2,
2.3 mm lines, 7.7 mm spaces; No. 3, 3.7 mm lines, 6.3 mm spaces; No. 4,
5.5 mm lines, 4.5 mm spaces. The cards are placed 50 feet from the observer
in line with the chimney, together with a white and a solid black card. The
observer glances quickly from the chimney to the cards and judges which one
corresponds with the color and density of the smoke. Ringelmann readings are
usually taken at 2 to 1 minute intervals during an hour or more. The readings
are plotted in a log which gives a good general idea of the manner and regu-
larity of smoke emission but is very unsatisfactory for ordinary stacks.
How should the combustion chamber be proportioned
for burning bituminous coals?
Ans. It should be extra large.
How is smoke classified with respect to intensity?
Ans. By dividing it into several shades or comparing it with
a smoke chart.
What determines largely the temperature of combustion?
Combustion
93
RINGELMANN CHART
Ans. The design of the furnace.
Give a definition of the term ashes?
Ans. All the mineral matter left after the complete combustion
of fuel.
Why do fuels contain incombustible matter?

5
3
N
I
•
PA
3.6
3.8
4.0
4.2 4.4
PER CENT HYDROGEN.
4.6 4.8
5.0
Fig. 16.-Ringelmann chart showing how the density of smoke varies with the
percentage of hydrogen in the coal.
NOTE.—Admiral R. T. Hall describes an electrical means of determining the
density of smoke used on the U. S. S. Conyngham. The basic principle is the
sensitivity of the metal selenium to light as affecting the passage of electric current.
A selenium disc connected to the ship lighting circuit was placed on one side of the
stack opposite a light on the other. The intensity of the beam of light striking
the disc of course varied with the density of the smoke. A milliammeter with a
suitably graduated scale indicated the changes in current due to the changes
in smoke density.
94
Combustion
Ans. Because the plants of which the coal was formed con-
tained inorganic matter and because of the earthy matter in
the drift of the coal period.

FOURTH
PIPETTE FOR
FINAL WASH
FROM FLUE
O
EVD C B
e
F
e
8
Fig. 17.-Four pipette Orsat apparatus for accurate analysis. The first pipette B
contains a solution of caustic potash, the second C, an alkaline solution of
pyrogallic acid and the remaining two D, and E, a solution of cuprous chloride.
Each pipette contains a number of glass tubes, to which some of the solution
clings, thus facilitating the absorption of the gas. In the pipettes D, and E,
copper wire is placed in these tubes to re-energize the solution as it becomes
weakened. The rear half of each pipette is fitted with a rubber bag, one of
which is shown at K, to protect the solution from the action of the air. The solu-
tion in each pipette should be drawn up to the mark on the capillary tube.
The various operations are performed the same as with the three pipette appar-
atus with the exception that after the gas has been in pipette D, it is given a
final wash in E, and then passed into the pipette C, to neutralize any hydro-
chloric acid fumes which may have been given off by the cuprous chloride
solution, which, especially if it be old, may give off such fumes, thus increasing
the volume of the gases and making the reading on the burette less than the
true amount.
Combustion
95
What are the principle constituents of ashes?
Ans. Silica, alumina, lime, oxide and bisulphide of iron.
What is clinker?
Ans. A product formed in the furnace by fusing together
impurities in the coal such as oxide of iron, silica, lime, etc.
Which coals clinker least under high temperature as
judged by the color of the ashes?
Ans. Those whose ashes are nearly pure white.
What substance in ashes causes clinker?
Ans. Oxide of iron.
With complete combustion of coal what percentage of
ashes remain?
Ans. It varies considerably for different coals, but average
values will be 5 to 10 per cent.
How a CO2 Recorder Works.-The principle upon which
most recorders work is based upon the absorption of CO2 from
flue gases by a solution of caustic potash.
There are four essential operations to be performed by a
recorder for each CO2 determination.
1. Measuring out a definite quantity of flue gases.
2. Passing the measured sample through the caustic potash
solution which absorbs the CO2, decreasing the volume of the
gases in proportion.
3. Recording the decreased volume after absorption of the
CO2 by the caustic potash solution.
4. Exhausting the recorded sample, thus bringing the appa-
ratus back to its initial condition, ready for the next gas sample.
96
Combustion
:
What does the CO2 percentage indicate?
Ans. The volume of excess air flowing through the furnace
and the power of the boiler.
Just what is this percentage?
Ans. It is the ratio between the air that is taken for a
useful purpose in burning the coal and that which is taken to
the wasteful end of cooling the furnace gases.
That is all it does indicate and its indications are only approxima-
tions.
:
WATYW
How a Boiler Makes Steam
97
A
How a Boiler Makes
Steam
CHAPTER 8
What is the basic principle in steam making?
Ans. An upset of hydraulic thermal equilibrium causing cir-
culation, that is, convection currents.
EXPANSION

SAME LEVEL
EQUAL
TEMPERATURE
LIGHT
WATER
C
CONTRACTION
ICE
FLAME
HEMA
ننا لاه
B
HEAVY
WATER
Figs. 1 and 2.-Glass U-tube partially filled with water illustrating expansion
and contraction of water with variation in temperature and resulting change
in weight per unit volume.
What causes convection currents?
Ans. A variation of temperature in different parts of a boiler.
See figs. 1 and 2.
98
How a Boiler Makes Steam
How does this variation of temperature cause convection
currents?
Ans. The water at high temperature weighs less than the
water at low temperature. Accordingly the low temperature
heavy water sinks to the bottom of the containing vessel and
pushes the high temperature light water up to the top.
A familiar example employing this method of circulation was intro-
duced in some early automobiles in which the radiators depended upon
HIGH TEMPERATURE

LIGHT WATER
C
HEATER
LOW TEMPERATURE
1111
WATER
HEAVY
HORGE
C
Fig. 3.-Elementary hot water heating system illustrating thermo-circulation.
temperature differences instead of forced circulation by pump now
universally employed. Also in hot water heating systems, as shown
in fig. 3.
Is this difference in temperature all that causes convec-
tion currents, that is circulation?
Ans. No.
How a Boiler Makes Steam
99
In boiler operation what additional condition accelerates
considerably the circulation due to the water at different
temperatures?
F
Ans. The formation of steam bubbles results in a mixture of
steam and water in the up flow side much lighter than the solid
column of cooler water in the down flow side.

人
​HOT
COLD
LIGHT
HEAVY
WATER
WATER
Fig. 4. Circulation of water in boiling. The lower and outer layers are first
warmed. These expand, and becoming less dense, rise to the surface, their
place being taken by the colder and denser layers, thus producing convection
currents as indicated by the arrows.
If a pot be filled with water and placed on an open fire
what happens?
Ans. It will be noticed as shown in fig. 4, that when it boils:
the water rises at the sides and sinks in the center.
100
How a Boiler Makes Steam
…………….
Why?
Ans. Fire being in contact with the sides, the water is heated
most at the sides causing it to expand, become lighter and rise,
being pushed up by the heavier water in the central part of the
vessel.
What happens as the rising expanded water reaches the
top of the vessel?

FORMATION OF STEAM BUBBLE
THE FORMATION OF STEAM

0000



GROWTH OF BUBBLE
DETACHMENT OF BUBBLE
BUBBLE RISING AND EXPANDING
BURSTING OF BUBBLE
Figs. 5 to 9.-The formation of steam showing what happens to each bubble.
Ans. The surface is cooled somewhat which causes it to con-
tract and becoming denser it naturally sinks.
Where does the formation of steam take place?
Ans. In the water directly in contact with the pot, especially
in the lower part where the temperature of the metal is highest.
K
How a Boiler Makes Steam
101
Describe the formation of steam.
Ans. A particle of water in contact with the metal is heated
until it is changed into steam, first appearing as a small bubble
which for a time clings to the metal, as in fig. 5.
What happens to the bubble?
Ans. Its size gradually increases by the addition of more
steam, formed from the surrounding water until it finally
disengages itself from the metal, as in fig. 7.
After disengagement of the bubble of steam what
happens?
Ans. Since it is much lighter than the water, it quickly
rises and bursts on reaching the surface, allowing the steam
to escape into the atmosphere, as in figs. 7 to 9.
What takes place during the ascent of the bubble and
why?
Ans. It expands because of the gradual reduction in pressure
due to the decreasing hydraulic head. Note expansion in figs.
6 to 8.
What kind of circulation is that just described as dis-
tinguished from another kind of circulation?
Ans. Natural or undirected circulation.
What is the other kind of circulation?
Ans. Directed circulation.
*
Why does a pot boil over with undirected circulation?
Ans. If, in fig. 10, the fire be very hot, steam bubbles will
rise from all points at the bottom in such quantities as to impede :
the downward flow of water, in which case the pot "boils over
102
How a Boiler Makes Steam
MERCY!
מע
バー
​ཀ༽ ཀ ་
>
تم
UNDIRECTED
CIRCULATION
DIRECTED
(RESTRICTED)
རྗ༽ སྤུ་
(~
"
£
??
обрат товар
(T) <
()
()
so
DIRECTING
BAFFLE
()
UNDIRECTED
(NATURAL)
Fig. 10.-Familiar coffee pot "boil over" due to undirected flow with accompanying reaction by the cook.
Fig. 11.-Directed flow with cylindrical baffle or inner vessel.
How may "boiling over” be prevented?
Ans. By introducing directed circulation as in fig. 11. Here a vessel of somewhat
smaller diameter with a hole in the bottom is lowered into the pot as shown, so


How a Boiler Makes Steam
103
fastened as to leave a small concentric space all around between
it and the pot.
In the case of the coffee pot, the familiar way of doing it without
any baffle device is shown in fig 12.
In what kind of boiler is the "pot" circulation just de-
scribed virtually reversed?
Ans. In the vertical or so called "upright" shell boiler as
shown in fig. 13.
UP FLOW ZONE
HOT
Tu
か
​
DOWN FLOW ZONE
COLD
OFF CENTER
Fig. 12.-Familiar "shove over" method of preventing a coffee boil over.
Why?
Ans. The coldest part of the boiler is at its shell.
Describe the circulation.
Ans. In the vertical boiler the current descends along the
shell to the lowest point and rises next to walls of the furnace
then continues upward along the tubular heating surface.
What is the importance of a free circulation in boilers?
Ans. Among other things it maintains the metal of the boiler
at a nearly uniform temperature which prevents unequal
متر
104
How a Boiler Makes Steam
expansion on its various parts, especially in boilers having thick
plates. It also facilitates the escape of steam from the heating
surface as soon as it is formed-a condition necessary to pre-
vent overheating of the plates which would occur unless they
be maintained in constant contact with the water.
Describe an experiment which shows the importance of
circulation in a boiler.

(Dub
T
wwwwwww
יד
DIH
F
ASCENDING LIGHT WATER
DESCENDING HEAVY WATER
COLD PART
Fig. 13.-"Reversed" circulation in vertical boiler.
Ans. Take a test tube, anchor a piece of ice at the bottom,
fill with water and apply heat at the top, as in fig. 14. The
water will boil at the top, but the temperature at the bottom
of the tube is not appreciably affected.
Why?
Ans. Water is a bad conductor and transmits heat principally
by convection, that is by circulation.
How a Boiler Makes Steam
105
In steam making, is all the heat applied transferred to
the water?
Ans. No, a considerable amount of the heat generated by the
fuel is lost.

BOILING WATER-
COLD
WATER
Mo
THI
Sal
ICE
*
Fig. 14.-Experiment to show the importance of circulation in boilers. Water
is a bad conductor and receives heat principally by convection. A test tube
filled with cold water having a piece of ice placed in the lower end is heated
at the top as shown. The water will soon boil at its upper surface while the
temperature of the bottom of the tube is not appreciably changed.
Name and describe an early arrangement for obtaining
directed flow.
106
How a Boiler Makes Steam
Ans. The Field drop tube boiler based on the principle shown
in fig. 15.
POOR
. CIRCULATION
OVERHEATED TUBE END
In this arrangement the heated water rises in the annulus between
the inner or directive tube and the exterior heating surface tube
while the cold water circulates down in the inner tube.

STEAM
pod opportu
EQE630.
ANCHORZU.
DECIMUZINOGE
RAPID CIRCULATION
Fig. 15.-Field tube without, and with inner circula-
tion tube, illustrating importance of rapid circula-
tion. Because of the poor circulation in tube L, the
excess steam forming at the bottom of the tube
tends to drive the water upward, thus the metal is
left unprotected and quickly becomes overheated
by the intense heat from the furnace. With an
inner tube to promote circulation as in tube F,
there is a constant flow of cool water over the
metal with the result that the steam is carried off
to the liberating surface as soon as it is formed,
thus preventing the metal becoming overheated.
However, inner tube or no inner tube, this circula-
tion makeshift is no good especially in marine
practice.
Why is this arrangement objection-
able?
[…………Ÿ!!!!!!
Ans. In the first place, with a multi-
plicity of closely spaced tubes, there is
bound to be turbulence or confused flow
in leaving the outer tube and entering the inner tube. As ordi-
narily constructed there is poor draught. Moreover in freezing
weather such a boiler cannot be drained without turning it
upside down. The only practical way to get the water out of
the tubes is to evaporate it, and if too hot a fire be used,
there is danger of burning the tubes.
This method of directed circulation is practically obsolete, and may
be dismissed as no good.
How a Boiler Makes Steam
107
The author objects to this contraption, not only for the
foregoing reason, but also because of the extra cost and weight
of the inner tubes, the latter item being highly objectionable
in marine practice especially in the case of high speed vessels,
since weight and high speed are directly opposed.
RED HOT PLATE
Another objection is that when the inner circulation tubes are not
provided, it results in such poor circulation as to drive the water off
DROP OF WATER
...་....་་
FILM OF STEAM

Fig. 16.-Drop of water on red hot plate illustrating the spheroidal state.
the bottom of the tubes, that is, resulting in the spheroidal state, as
shown in fig. 16,— at least spasmodically.
What is the spheroidal state?
Ans. The condition of a liquid, as water, when being thrown
on the surface of a highly heated metal, it rolls about in
spheroidal drops or masses, at a temperature several degrees
108
How a Boiler Makes Steam
below ebullition and without actual contact with the heated
surface. This phenomenon is due to the repulsive force of heat
and the intervention of a cushion of vapor.
Boiler Types
109
CHAPTER 9
Boiler Types
Why is there such a great variety of boiler types?
Ans. It is due to the many different kinds of service for
which they are intended, the varied conditions accompanying
their use, and the competition among engineers who have
sought to produce at moderate cost, boilers that will be safe,
durable, compact and economical.
How may the multiplicity of boiler types be briefly
classed?
Ans. They may all be grouped into a few general divisions.
General Classification
All boilers may be classed broadly as:
1. With respect to service, as
a. Stationary heating
power
b. Locomotive
c. Marine
2. According to form of construction:
a. Fire tube (shell)
b. Water tube (some so called)
110
Boiler Types
What is a fire tube?
Ans. One in which the products of combustion pass through
the tube which is surrounded by water, as shown in fig. 6.
What is a water tube?
Ans. One which is surrounded by the products of combustion,
the water being inside the tube, as in fig. 7.
MAIN OUTLETS

295
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030
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THROUGH STAYS
Fig. 1.-Horizontal return tubular boiler.
LUGS
8
How is a tube fastened to a sheet?
Ans. By expanding, as in fig. 8.
105
What is the difference between a tube and a flue?
Ans. A tube is a lap welded or seamless cylindrical shell
made in small sizes. A flue is a large cylindrical shell; it may
be seamless, lap welded or riveted.
Boiler Types
111
SPARK
ARRESTER
SMOKE BOX
DOOR
EXIT FOR
CINDERS
Fig. 2.-Locomotive boiler.
SMOKE STACK
NOZZLE
SHELL
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BAFFLE PLATE
EXHAUST PIPE
WHISTLE
STEAM DOME
ID
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ASH PAN
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FURNACE
DOOR

BRAN
V V V V V V V V V O
What is a sheet?
Ans. A flat plate or head called a sheet having holes for receiving the tubes or flues.
112
Boiler Types

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LARGE COMBUSTION CHAMBER-
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Figs. 3 and 4.-Clyde or dry back and Scotch water back boilers. Some
people insist on calling Clyde boilers Scotch boilers even though they know
better.
000000

Fig. 5.-Combined vertical horizontal fire box shell boiler with horizontal fire
tubes.
Boiler Types
113


FIRE TUBES
0000000
0 0 0 0 0 0 0
0000
00:00 00:0
- O O O O O
SHEET
EXPANDED JOINT
TUBE
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Figs. 6 and 7.-The difference between fire tubes and water tubes. It's simply
this: Fire flows through fire tubes and water flows through water tubes.
SMALL DIAMETER
SHEET
WATER TUBES
SHEET
1
KE


RIVETED JOINT
FLUE
LARGE DIAMETER
-SHEET
t
Figs. 8 and 9.-Differences between a tube and a flue. The chief differences
are sizes, thickness, method of manufacture and making the joint as by expand-
ing and riveting as shown.
114
Boiler Types
How is a flue fastened to a sheet?
Ans. By flanging and riveting, as in fig. 9.
Why are boilers with flues practically obsolete?
Ans. Because of inadequate heating surface.
What is a single tube boiler?
Ans. One made up of plain tubes, as in fig. 10.
SINGLE


DOUBLE
CIRCULATOR INNERTUBE
Figs. 10 and 11.-Difference between single and double water tubes.
What is a double tube boiler?
Ans. One having an auxiliary tube placed inside each main
tube to give circulation, as in fig. 11.
What is a non-sectional boiler?
Ans. One in which all the tubes are in communication with
a common header at each end, as in fig. 12.
What is a sectional boiler?
Ans. One in which the tubes are divided into groups, each
Boiler Types
115
NON-SECTIONAL
OVER DISCHARGE
WATER LEVEL
PRIMING TUBES
UNTO
THROUGH
TUBE
HATEKEE
BAFFLE PLATE
#
SECTIONAL


Figs. 12 and 13.-Difference between non-sectional and sectional boilers
as explained in the text.
1011
WATER LEVEL
SEN
UNDER
DISCHARGE
DROWNED TUBE
SUBMERGED
TUBE


CONE
Figs. 14 and 15.-Through (sometimes called flush) tube and submerged
tube vertical boilers.
116
Boiler Types

DRYER
1/2 IN ASBESTOS
BOARD
NO. 12 U.S. GAUGE
COLLECTOR.
SEPARATOR
AUXILIARY
OUTLET
WATER LINE
14 STEEL PLATE-
TENSILE STRENGTH
55,000 LBS.
DOUBLE RIVETED BUTT
AND DOUBLE STRAP
JOINT EFFICIENCY 82.8%
IIN LAYER ASBESTOS
INSULATION
¼ OAK LAGGING.
6 TUBE SHEET.
HAND HOLES
FLANGE 1/2 RADIUS
TUBE SHEET
13/16 STAY BOLTS
PITCH 44 × 4¾¾
$16 FURNACE PLATE-
3 WATER LEG
HAND HOLES
ASH PAN 8" THICK
-DIAM TUBE LIMIT 331
gods
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DIAM FURNACE 36
DIAM SHELL 40
CHHANDO O O O O
DIAM LAGGING 43.
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0 0 0 O O O
GRATE ARCA 2 AIR SPACES
722 SQ FT
MIERDIE
200 OO
18
-2-1156
8X16
DOOR
Fig. 16.-Graham through tube vertical marine boiler.
TOTAL HEATING SURFACE
357 SQ.FT.
RATIO 49.4:1
555 TUBES 1"x2"-18"
3/32 THICK
6.
3/4 FEED
INLET
I" BLOW
OFF
4-2 × 14
LUGS
Boiler Types
117
group communicating with a header at each end, making
independent units, as in fig. 13.
What is a through tube boiler?
Ans. A vertical shell boiler having tubes extending from the
lower tube sheet the full length of the shell, as in fig. 14.
What is a submerged tube boiler?

NUMEROUS
BRACES
། ་་ །
FIRE BOX
DRY BOTTOM
Fig. 17.-Marine type of locomotive boiler with dry bottom fire box.
Ans. A vertical boiler having tubes extending from the lower
tube sheet to an upper submerged tube sheet, the latter being
connected to a head at the top by a "cone", as in fig. 15.
The author considers the necessity for this construction greatly over-
rated except in some special cases. Take for instance the author's
boiler, fig. 16, there is no necessity for submerged tubes even when
forced, because an abnormally high water level can be carried due to:
1, separator; 2, collector; and 3, dryer. Note small diameter tubes
compared with their length.
What is a fire box boiler?
118
Boiler Types

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Fig. 18.-Method of providing for expansion by link suspension. As may be seen, the weight of the boiler
is carried by the steel work, thus relieving the brick work of this duty.
Boiler Types
119
Ans. One having the fire within a fire box, although external
to the shell, is rigidly connected to it, as in fig. 17.
The fire box is usually of steel plates instead of bricks.
What is a horizontal return tubular boiler?
Ans. One so arranged that the products of combustion after

WATER
WATER
PHILLI
-WATER
Fig. 19.—Modern Scotch boiler showing general arrangement. Note that the
combustion chamber is entirely surrounded by water, that is, except for the
opening where it is attached to the furnace.
120
Boiler Types
passing along the length of the shell, return in an opposite
direction through the tubes before passing up the stack. See
fig. 18.
What is a Scotch boiler?
Ans. A horizontal boiler in which the combustion chamber
at the end is entirely surrounded by water-mark ye entirely
surrounded by water. See fig. 19.

BRICK
B
X
Uz
NO WATER
HEAT LOSS HERE
Fig. 20.-Modified Clyde (dry back) boiler with short fire tubes at rear of fur-
nace corrugated flue, the object being to provide circulation under the flue.
What is a Clyde boiler?
Ans. A boiler similar to a Scotch boiler, but instead of a
water space at the back end of the combustion chamber, a
removable back which is lined with some insulating material
such as asbestos or fire tile.
Why the sarcasm in the definition of a Scotch boiler?
Ans. Because there are still some non-descript individuals,
who either through ignorance or questionable motives call a
Clyde boiler a Scotch boiler.
Boiler Types
121
Evidently a Clyde boiler is cheaper in construction than a Scotch
boiler and due to the loss of B.t.u. through the insulation, a Clyde
boiler is not as efficient as a Scotch boiler - this must be self evident.
M
What are Galloway tubes?
Ans. Obsolete transverse tubes placed in a flue and attached
to openings in the side of a flue to increase the heating surface,
as in fig. 21.

Fig. 21.-Galloway flues (so called "tubes"). As arranged in independent or
through flue. In construction, the Galloway flue is tapered to permit the
lower flange being inserted in the upper opening to get the flue into place.
Some makers insert cylindrical pipes and weld them to the flue.
What is the difference between Cornish and Lancashire
boilers?
Ans. They are respectively one and two flue boilers.
What is a porcupine boiler?
Ans. One having a vertical drum into which are screwed a
multiplicity of horizontal radial short tubes having their outer
122
Boiler Types
ends closed and the ends of square section which enables them
to be screwed into the drum with a wrench, as in fig. 22.
What is an internally fired boiler?
Ans. One in which the furnace is within the shell, being
surrounded by water. Example, the familiar vertical shell
boiler, as in fig. 16.

A
::
STEAM
WATER
GRATE
RADIAL TUBES
"
Fig. 22.-Single tube porcupine boiler. It consists of a central column of
heavy hydraulic pipe, into which tubes are screwed. The vertical drum is ex-
tended above the radial tubular heating surface to form sufficient space for the
steam. The heads are welded in.
Boiler Types
123
What is an externally fired boiler?
Ans. One in which the furnace is outside the shell, the furnace
walls being usually of fire brick. Example, the familiar hori-
zontal return tubular boiler as shown in fig. 18.
What is the comparison between tubes and pipes with
respect to their use for heating surface in boilers?
Ans. Tubes are much lighter than pipes. In case of repair
single tubes may be removed, but in the case of pipe boilers,
several lengths of pipe are made up into a coil necessitating
the removal of the whole coil to get at any of its component
lengths.
How much lighter is a square foot of tube heating surface
than of pipe heating surface?
Ans. It depends upon the size of the tubes and pipes.
For instance weight of standard 2 inch (.13 B.w.g.) boiler tube is
1.932 lbs. per lineal foot; weight of standard 1 inch pipe (external
diameter 1.9 in.) is 3.631 lbs.
The length of each per square foot of external surface is: tube,
1.91 ft.; pipe, 2.01 ft.
What is the lightest gauge tubes used standard practice?
Ans. No. 13 B.w.g.
What is the smallest size tube used except in special
cases?
Ans. One inch o.d.
O.d. means outside diameter.

124
Boiler Types
What is the difference between a tube and a pipe?
Ans. The metal of a tube is thin, being proportioned only to
withstand the steam pressure whereas a pipe is made of rela-
tively thick metal.
Why is a tube of thin metal and a pipe of relatively
thick metal?
403
Lobs
Fig. 23. Super steam generator built by the author. View taken 5 minutes
after lighting fire shows steam blowing off at 75 lbs. pressure. For details of
design see page 2077, Audel's Engineers and Mechanics Guide No, 5, by
the author. The design includes: steam generating coils, feed water heater,
super heater, water cooled furnace and "water grate.'
Ans. A tube is expanded into the tube sheet whereas a pipe
must be of extra thickness because of the screwed joint.
NOTE. The author objects to the practice of some manufacturers of cast iron
sectional house heating boilers of calling some of the water passages "tubes."
They are anything but tubes and it is ridiculous to call them tubes.

Boiler Types
125
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Fig. 24.-An outstanding example of pipe boiler construction. Note the specia!
unions top and bottom permitting easy removal of any coil.
126
Boiler Types
Why do the manufacturers of "pipe boilers" object to
calling them pipe boilers?
Ans. For some phony reason they like to call them "water
tube boilers"-in this case a misnomer.
What is the difference between a boiler and a generator?
Ans. A boiler carries a considerable volume of water in pro-
portion to its heating surfaces, and is therefore not very sensitive
to sudden changes in the rate of combustion, whereas a generator
carries no excess volume of water but converts the water into
steam as it transverses the heating surface progressively from
one end to the other; it has no water level as indicated by
water gauge or gauge cocks.
Name two types of generator.
Ans. Semi-flash and flash.
A semi-flash generator is a combination of a shell and flash boiler.
It consists of a drum or shell holding a body of water and a coil of
pipe forming the heating surface.
A flash generator consists of a long length of tubing formed into a coil,
usually water entering at the top and being "flashed" into steam at some
intermediate point coming out of the lower layer as superheated steam.
The term boiler is frequently used in place of generator.
Instant Steam
126A
CHAPTER 9-A
Instant Steam
Strictly speaking, that is, with mathematical precision, the
title of this Chapter is a misnomer, because no physical change
can take place instantaneously, which means without lapse of
time. The author, however, advisedly takes a little license here
in calling this Chapter "Instant Steam" to forceably impress
upon the reader the fact that there are boilers on the market
to-day which can generate steam from cold water to pressures
up to 300 lbs. in less than two minutes,* instead of taking over
two hours as in the case of some Scotch boilers!
What kind of boiler can generate steam in less than two
minutes?
Ans. An oil burning flash boiler.
What is necessary for the satisfactory operation of this
type boiler?
Ans. Complete automatic control of fuel, water and steam,
also arrangement of steam separator to provide required steam
space to dampen pressure fluctuations.
Describe the automatic control.
Ans. A single motor drives all necessary units, that is, it
*NOTE.-The author's coal burning super-heated steam generator, produces
super-heated steam from a cold water start in five minutes. See pages 124 and 204.
126B
Instant Steam

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-BURNER
Instant Steam
126C
operates feed water pump, fuel pump, magneto for ignition and
blower for combustion air. Thus the fuel supplied to the burner
is automatically regulated in relation to the amount of air
delivered for combustion.
How are the units controlled?
Ans. By the steam demand.
What are the applications of these outfits?
Ans. They are used for a variety of industrial and marine
applications wherever there is a demand for either a steady
source of steam or as an emergency unit ready to pick up the
load when needed. They are used in large plants as standby
units for extra loads that cannot be handled by the main boiler
in severe cold weather when heating requirements are high.
Name two types of these flash boilers?
Ans. 1. The recirculating type, and 2, the direct or non-
recirculating type.
Recirculating type Boiler-The complete boiler comprises a re-
circulated type coil steam generator and a steam separator as shown in
fig. 1. A portion of the water pumped into the steam generating coils
is passed over into the steam separator and is recirculated to reduce
the possibility of scale formation on the inside of the coils.
The boiler is complete and self-contained and includes all the ac-
cessories and controls, such as the burner, a forced draft blower, feed
water pump, fuel pump, burner control, water level control, low water
automatic fuel cut-off, stack switch, high temperature switch, steam
pressure switch, boiler control panel, an automatic ignition system,
motor for driving blower, fuel pump and water pump, gauges, relief
valves, safety valves, stop valve etc., requiring only connection to
stack (smoke pipe), electrical supply, fuel supply and water supply.
Low voltage, electrical overload and short circuit protection are pro-
vided in addition to protective devices against excessive steam tem-
perature, excessive stack temperature and low water level.
Essentially, this type of boiler consists of a staggered coil assembly,
into which water is pumped for evaporation into steam, a combustion

126D
Instant Steam
chamber surrounded by the coil assembly, a fire pot below and com-
bustion chamber and the burner.
The coil assembly is designed and arranged to allow for free ex-
pansion, but is held in firmly staggered relation for maximum heat
transfer. The ends of the coils are so shaped that an effective seal is
made to prevent by-passing hot gases.
The coil assembly is made up of three sets of coiled, welded, steel
tubing. The framework of the boiler is of fabricated steel. The fire pot
is moulded of plastic refractory material.
entr
VAPOR
UP
anion
D
Figs. 2 and 3.-Motorized valve. A small motor drives a gear train which
operates the valve. Used for automatic control of water or steam.
astiod
The recirculating water returning from the steam separator is fed
into the intermediate generating coil of the boiler.
An excess of water is circulated through the boiler. The excess water
is separated out of the steam in the steam separator and recirculated
through the boiler by being fed into the intermediate coil of the boiler.
The water feed to the boiler is governed by the water level in the
steam separator by means of the water level control, which allows
the make-up water supply to be by-passed back to the tank instead
Instant Steam
126E

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Fig. 4.—Wiring diagram for automatic control without photo-electric control.
126F
Instant Steam

FIRE
POT
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poat
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Fig. 5.-Direct or Non-Recirculating type flash boiler detail showing inverted burner.
AIR
RING
Instant Steam
126G
of being fed into the outer coil of the boiler whenever the water level
in the steam separator begins to rise above half of a gauge glass.
Direct or Non-Recirculating type Boiler
The coils are ar-
ranged similarly to those of the type just described. Incoming air to
the burner is delivered by a blower, which is belt driven from the
motor. The motor also drives the water pump and the fuel pump.
A damper at the air intakes allows for the adjustment of the amount
of air delivered by the blower.
The water for evaporation is drawn from the storage tank through
the feed water treater and is then pumped through the lower portion
of the fuel control to the steam generating coils. During operation,
an excess of water is circulated through the coils. The excess water
circulated is about 5% more than is required for evaporation into
steam, but the steam generating unit is capable of proper operation
with anywhere from 2% to 20% excess water circulation. This excess
water maintains an even temperature in the steam generator and
flushes out the scale forming matter from the coils. The water and
sludge are separated out from the steam in the steam separator, which
has a separating chamber and a mud sump to remove the solids from
the steam centrifugally, for the purpose of blowing them out periodically
through a foot lever operated blowdown valve provided for the purpose.
An inverted bucket steam trap is provided to return the excess water.
The ignition is constant, so that should any of the safety devices
shut off the fire, it will automatically relight, when normal conditions
are restored. Ignition is provided by a rotary converter, which con-
verts the direct current input to alternating current, which is then
stepped up to the required 10,000 volts for ignition purposes by a
transformer. See wiring diagrams figs. 4 and 6.
A five-stage fire is used. The fire will vary automatically from one
stage to another, depending upon the desired steam pressure setting
and the steam demand. There are two selectable ranges of operation,
low and high. The low range on the "START" position of the Operating
Switch is used in mild weather and whenever the steam generator is
started. The high range, on the "RUN" position of the switch is nor-
mally used in regular service, after the steam generator has been
started and has been operating on low range ("START" position) for
about 2 or 3 minutes.
The steam pressure switch through its five contacts, operates relays
to increase or decrease, in five successive stages, the main motor speed,
thus varying the water and fuel delivery as well as the delivery of air
by the blower. Consequently, the output of the steam generator is
increased or decreased progressively, in accordance with the setting
of the pressure switch and the actual steam demand, dependent also
126H
Instant Steam
upon the range, low or high selected. The proportions of fuel to water
and of air for combustion are maintained relatively automatically,
when properly set. Excess steam pressures over the pressure switch
setting will entirely shut down the steam generator, even when operat-
ing on low range.

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Fig. 6.-Wiring diagram for automatic control with photo-electric control.
The Nature of Boilers
127
CHAPTER 10
The Nature of Boilers
Define a boiler with respect to the duty it performs.
Ans. A boiler is a closed vessel arranged to transfer heat
from burning fuel to water within the boiler, converting the
water into steam, usually of a pressure greater than that of the
atmosphere.
For the thermal action, what are the two essential parts
of a boiler?
Ans. The grate, and the heating surface, as in fig. 1.
What is the grate?
Ans. That part of the furnace which is composed of alternate
bars and spaces to support the fire and admit the air.
How is the area of the grate expressed?
Ans. In square feet.
What is the heating surface?
Ans. That part of a boiler exposed to the heat on one side
and the water on the other.
How is the area of the heating surface expressed?
Ans. In square feet.
128
The Nature of Boilers
What is the best form of heating surface and why?
Ans. The tubular form because for a given strength it gives
the least weight per square foot of heating surface.
How long should the gases of combustion be in contact
with the heating surface?
Until cooled to such an extent that active and quick trans-
mission of heat stops.

DISENGAGING SURFACE
LIBERATING AREA'
50-00-
B
SERIES
CONNECTION
MIGHT
All
Fig. 1.-Elementary boiler illustrating the two essential parts necessary to make
steam, that is, a grate and heating surface.
What is the relation between grate and heating surface
areas called?
Ans. The grate-heating surface ratio. Preferably stated as
heating surface-grate ratio.
Thus, if there be, say, 25 sq. ft. of heating surface per sq. ft. of grate
it is stated as: 25 to 1.
The Nature of Boilers
129
What part of a tube or pipe is considered as heating
surface?
DEAD
PLATE
Ans. The internal surface of a fire tube and the external
surface of a water tube or pipe, as shown in figs. 3 and 4.

GRATE BARS
END SUPPORT-
Fig. 2.-Detail of dead plate or front support and grate bars.
INTERNAL
SURFACE
FIRE
-
EXTERNAL
SURFACE


-WATER=
WATER
FIRE
Figs. 3 and 4.-Basis of measurement of heating surface of 1, fire tubes, and 2,
water tubes.
What is the area of the heating surface frequently used
to express?
Ans. The "horse power" of the boiler.
How about the criticism of this term "boiler horse
power"?
130
The Nature of Boilers
Ans. It is the critics who should be criticized rather than
the term.
It is the ignorance of the public that causes confusion, not the term.
One boiler horse power is a close approximation to the horse power and
equals 33,478.8 B.t.u. per hour. See fig. 5.
BOILER HORSE POWER
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Fig. 5.-One boiler horse power. By definition: A unit of power adopted by
the judges at the Philadelphia Exhibition in 1876, known as the Centennial
Standard: It equals the evaporation of 30 lbs. feed water per hour, from a feed
temperature of 100° Fahr. to steam of 70 lbs. gauge pressure. This is equivalent
to 33478.8 B.t.u. per hour, or the evaporation of 34½ lbs. of water at 212°.
Al
What is the function of the grate?
Ans. To support the fuel and provide spaces through which
air enters distributed throughout the fuel.
What should be the shape of the grate for convenient
firing and why?
The Nature of Boilers
131
Ans. It should be wide rather than deep to allow the fireman
to spread the fuel in nearer uniform thickness.
HEATING
What determines the number of pounds of fuel that can
be burned?
Ans. The area of the grate and the draught.
5-10:1
VERTICAL
H
20:1


WATER TUBE
HORIZONTAL

30:1

LOCOMOTIVE

60:1
25-50:1
Figs. 6 to 10.-Familiar type boilers illustrating various grate heating sur-
face ratios.
NOTE. The ratio of heating surface to grate area varies widely according to
conditions. With very low rates of combustion it may be say 20 to 1, and for
very high rates as in locomotive practice, as much as 75 to 1 or more. In general,
with ordinary rates of combustion, the ratio of heating surface to grate area
varies usually between 30 to 1 and 40 to 1, because it has been found that the
heat of the gases produced from the fuel on one square foot of grate area can be
effectively and economically absorbed by from 30 to 40 square feet of heating
surface. The ratio is preferably stated as under the illustrations.
132
The Nature of Boilers
How is the rate of combustion expressed?
Ans. As pounds of fuel per sq. ft. of grate per hour.
Give some typical grate heating surface ratios.
Ans. 5 to 10:1, for ridiculous heating boilers; 20:1 small
vertical boilers; 30:1 horizontal return tubular boilers; 25 to
50:1 water tube boilers; 60:1 locomotive boilers. See figs. 6 to 10.
MULTI-DIVISION

SHORT TRAVEL
CAREER
CHHAHAALLEN
KALENHAALDEN
W
ÿÿÿÿÿÿ
Fig. 11.-Efficient arrangement of the heating surface-multi-division.
How does the rate of combustion vary?
Ans. From 3 or 4 lbs. per sq. ft. of grate per hour to 60 lbs.
or more depending upon the type of boiler.
How many lbs. of water are evaporated per hour per lb.
of coal ("from and at 212° Fahr.")?
•
The Nature of Boilers
133
Ans. Approximately 8 to 11 lbs.
Upon what does the evaporation rate depend?
Ans. Upon the quality of coal grate-heating surface ratio and
efficiency of the heating surface.
How should the gas passages be arranged?

AGO'YDUN ONDUL
ROMANIA!
MÍNGUEUM
Mult
Fig. 12.-Plain circular grates for vertical boilers made in from 2 to 4 sections
for 20 to 60 in. boilers, grate diameter 14½ to 52 in. The standard air space
is 3% in.
Ans. They should be so arranged that the whole heating
surface can readily absorb the heat of the gases, for instance,
as in fig. 11.
What is the proportion of air space through the grate to
the total area of the grate?
Ans. The area of the air space is usually from one third to
one half of the total grate area. A grate with liberal air passages
is shown in fig. 12.
134
The Nature of Boilers
What is the liberating surface?
Ans. The water surface or area of contact between water
and steam.

-UNSTEADY PRESSURE
PRIMES EASILY
SMALL
DOES NOT
PRIME EASILY
STEAM SPACE
LIBERATING SURFACE
LARGE
STEADY
PRESSURE
STEAM SPACE
LIBERATING
SURFACE
TOIM
Figs. 13 and 14.-Influence of the size of steam space and liberating surface.
The steam space forms a reservoir for the storage of steam, hence if it be small,
as in fig. 13, a sudden and large demand for steam will cause a considerable
drop of pressure and the accompanying violent ebullition to re-establish
equillibrium between pressure and temperature will cause priming, carrying
over a large amount of spray into the steam main. The priming effect being
increased by the small area of liberating surface for the discharge of steam into
the steam space. When the steam space and liberating surface are large as in
fig. 14, the opposite conditions obtain.
The Nature of Boilers
135
This is sometimes called the disengaging surface as distinguished
from the submerged area of the tube openings into the drum of a water
tube boiler, the total area of these tube openings being called the
liberating area because it is here that the steam bubbles are "liberated"
from the tubes.
What is the object of the liberating or disengaging
surface?
D
SPRAY
Ans. It provides for the escape of the steam bubbles from
the water.

PRIMING
HEAVY DEMAND
ABNORMAL
WATER
LEVEL
BEER LIKE FOAM
NORMAL
WATER
LEVEL
FOAMING
POORLY DEFINED
WATER LEVEL
IMPURE OR DIRTY
WATER
ally
B
||
mmm
|||||||
mont
Figs. 15 and 16.-Elementary boilers illustrating the difference between prim-
ing and foaming and the conditions which produce these effects.
What is its real object?
Ans. To prevent turbulence or priming during disengage-
ment. Figs. 13 and 14 show results with small and large
liberating surface.
What is priming?
Ans. The carrying of small water particles in dangerous
136
The Nature of Boilers
quantities into the steam rendering it unfit for use in engines,
as in fig. 15.
What is foaming?
Ans. The mixing of steam and water in a boiler accompanied
by violent ebullition, as shown in fig. 16.
What causes foaming?
Ans. The causes are: Dirty water, trying to evaporate more
water than the size and construction of the boiler is intended
for, taking the steam too low down, insufficient steam room,
imperfect construction of boiler, and sometimes it is produced
by carrying the water line too high..
How much water should be carried in a boiler?
Ans. There should be enough to cover all the heating surface
subjected to the intense heat of the fire, at least several inches
deep, giving due consideration to inclined positions which boilers
other than stationary may assume, as for instance, tractors,
locomotive or marine boilers.
In large plants why are several boilers used instead of
one of equivalent capacity?
Ans. 1, for mechanical reasons; especially in the case of shell
boilers the size is limited; 2, in case of accident, only part of
the boiler plant need be shut down during repair; 3, for variable
load, the number of boilers in operation may be altered to suit
the demand for steam.
What is the chief difference in behavior of water tube
and shell boilers?
Ans. A water tube boiler is more sensitive to changes in
combustion conditions than a shell boiler.
The Nature of Boilers
137
Why?
Ans. Its response to changes in the rate of combustion is
quicker because it carries less water in proportion to the heating
surface.
1
Give some other differences.
Ans. More sensitive pressure fluctuations with variations in
load. Water tube boilers require more attention to feed pumps
because of the small amount of water carried.

DEAD SPOT
COLD WALL
KILLS FIRE
HENDET
WIMM
CONSIDERABLE B.t.u.
ABSORBED BY WATER
PP!
ˇˇˇˇˇˇˇˇˇˇ W
ASHES AND
PARTLY BURNED
COAL
Fig. 17.-Characteristic of the internal boiler furnace.
What kind of steam will a through tube vertical boiler
generate especially when the water is low in the glass
and why?
Ans. Slightly super heated steam because of the heat given
off by that portion of the tubes not in contact with the water.
138
The Nature of Boilers
What are the characteristics of an internal boiler furnace?
Ans. It is more efficient thermally than the external furnace,
but combustion is not so good near the cool walls. See fig. 17.
What are the characteristics of an external boiler furnace?
Ans. The surrounding brick work is subject to heat loss by
radiation, however, the combustion is better, no dead spots
adjacent to the brick.
Boiler Materials
139
CHAPTER 11
Boiler Materials
In the construction of a steam boiler although the variety of
materials is small, yet the subject of boiler materials is of im-
portance both to designer and operating engineer. What the
engineer should know about these metals is given briefly in the
following:
愚
​Definitions
Alloy cast irons. -Irons which owe their properties chiefly to the
presence of an element other than carbon.
Alloy steels. -Steels which owe their properties chiefly to the pres-
ence of an element other than carbon.
Basic pig iron. - Pig iron containing so little silicon and sulphur that
it is suited for easy conversion into steel by the basic open-hearth process
(restricted to pig iron containing not more than 1.00 per cent of silicon).
-
Bessemer pig iron.-Iron which contains so little phosphorus and
sulphur that it can be used for conversion into steel by the original or
acid Bessemer process (restricted to pig iron containing not more than
10 per cent of phosphorus).
Bessemer steel. -Steel made by the Bessemer process, irrespective
of carbon content.
Blister steel. —Steel made by carburizing wrought iron by heating
it in contact with carbonaceous matter.
Cast iron. -Iron containing so much carbon or its equivalent that
it is not malleable at any temperature. The committee recommends
drawing the line between cast iron and steel at 2.2 per cent carbon.
Cast steel. The same as crucible steel; obsolete, and confusing;
the terms "crucible steel" or "tool steel" are to be preferred.
Charcoal hearth cast iron. -Cast iron which has had its silicon
and usually its phosphorus removed in the charcoal hearth, but still
contains so much carbon as to be distinctly cast iron.
Converted steel. The same as blister steel.
Crucible steel. -Steel made by the crucible process, irrespective
of its carbon content.
140
Boiler Materials
Gray pig iron and gray cast iron. -Pig iron and cast iron in the
fracture of which the iron itself is nearly or quite concealed by graphite,
so that the fracture has the color of graphite.
Malleable castings.—Castings made from iron which when first
made is in the condition of cast iron, and is made malleable by subse-
quent treatment without fusion.
Malleable iron. -The same as wrought iron.
Malleable pig iron.—An American trade name for the pig iron
suitable for converting into malleable castings through the process of
melting, treating when molten, casting in a brittle state, and then mak-
ing malleable without remelting.
Open hearth steel.-Steel made by the open-hearth process irre-
spective of its carbon content.
Pig iron. Cast iron which has been cast into pigs direct from the
blast furnace.
Puddled iron. -Wrought iron made by the puddling process.
Puddled steel.-Steel made by the puddling process, and neces-
sarily slag-bearing.
Refined cast iron.-Cast iron which has had most of its silicon
removed in the refinery furnace, but still contains so much carbon as
to be distinctly cast iron.
Shear steel.-Steel, usually in the form of bars, made from blister
steel by shearing it into short lengths, piling, and welding these by
rolling or hammering them at a welding heat. If this process of shearing,
etc., be repeated, the product is called “double-shear steel."
Steel.-Iron which is malleable at least in some one range of tem-
perature and, in addition, is either 1, cast into an initially malleable
mass; or 2, is capable of hardening greatly by sudden cooling; or⚫3, is
both so cast and so capable of hardening.
Steel castings. —Unforged and unrolled castings made of Bessemer,
open-hearth, crucible, or any other steel.
Washed metal. -Cast iron from which most of the silicon and
phosphor have been removed by the Bell-Krupp process without re-
moving much of the carbon, still contains enough carbon to be cast iron.
Weld iron. -The same as wrought iron; obsolete and needless.
White pig iron and white cast iron. -Pig iron and cast iron in
the fracture of which little or no graphite is visible, so that their
fracture is silvery and white.
Wrought iron. -Slag-bearing, malleable iron, which does not harden
materially when suddenly cooled.
Properties of Boiler Materials
141
CHAPTER 12
Properties of
Boiler Materials
It is essential that anyone engaged in the design, construction,
erection or operation of a steam boiler should be familiar with
the nature of the various materials entering into its construction.
A material is said to possess certain properties which define
its character or behavior under various conditions.
The following definitions of terms used to express the proper-
ties of materials entering into boiler construction should be
noted.
Definitions
Define brittle.
Ans. Breaking easily and suddenly with a comparatively
smooth fracture; not tough or tenacious.
This property usually increases with hardness. The hardest and most
highly tempered steel is the most brittle; white iron is more brittle
than gray, and chilled iron than any other. The brittleness of castings
and malleable work is reduced by annealing.
Define cold short.
Ans. The name given to the metal when it cannot be worked
under the hammer or by rolling, or be bent when cold without
cracking at the edges.
142
Properties of Boiler Materials
Such a metal may be worked or bent when at a great heat, but not
at any temperature which is lower than about that assigned to dull red.
Define cold shut.
Ans. In foundry work, when through cooling, the metal
passing round the two sides of a mold, does not properly
unite at the point of meeting.
Define ductile.
Ans. Easily drawn out; flexible; pliable. Material, as iron, is
"ductile" when it can be extended by pulling.
Define fusible.
Ans. Capable of being melted or liquefied by the action of
heat.
Define hardness.
Ans. The quality of being not easily penetrated or separated
into parts; the quality of not yielding to pressure.
Define homogeneous.
Ans. Of the same kind or nature; hence, homogeneous, as
applied to boiler plates, means even grained.
In steel plates there are no layers of fibers, and the metal is as strong
one way as another.
Define hot short.
Ans. More or less brittle when heated; as hot short iron.
Define melting points of solids.
Ans. The temperature at which solids become liquid.
Properties of Boiler Materials
143
All metals are liquid, at temperatures more or less elevated, and they
probably all turn into gas or vapor at very high temperatures. Their
melting points range from 39 degrees below zero of Fahrenheit's
scale, the melting, or rather the freezing point of mercury, up to more
than 3,000 degrees.
Define resilience.
Ans. The quality of elasticity; the property of springing back
or recoiling upon removal of a pressure, as with a spring.
Define specific gravity.
Ans. The weight of a given substance relative to an equal
bulk of some other substance which is taken as a standard of
comparison.
Water is the standard for liquids and solids, air of hydrogen for
gases. If a certain mass be weighed first in air, then in water, and the
weight in air divided by the loss of weight in water, the result will
give the specific gravity; thus, taking a ten pound piece of cast iron,
its weight suspended from the scale pan in a bucket of water, will be
8.6 lbs., dividing 10 by the difference 10-8.6 or 1.4, the answer will
be 7.14, which is the specific gravity of cast iron.
Define strength.
Ans. Power to resist force; solidity or toughness; the quality
of bodies by which they may endure the application of force
without breaking or yielding.
Define tenacity.
Ans. The attraction which the molecules of a material have
for each other, giving them the power to resist tearing apart.
The strength with which any material opposes rupture; its
tensile strength.
Define tough.
Ans. Having the quality of flexibility without brittleness;
144
Properties of Boiler Materials
capable of resisting great strain; able to sustain hard usage;
not easily separated or cut.
Material, as iron, is said to be tough, when it can be bent first in one
direction, then in the other, without fracturing. The greater the angle
it bends through (coupled with the number of times it bends) the
tougher it is.
Define weldable.
Ans. A term applied to material; as iron, if it can be united,
when hot, by hammering or pressing together the heated parts.
The nearer the properties of the material, after being welded, are to
what they were before being heated and welded, the more weldable it is.
Tests of Boiler Materials
145
T
CHAPTER 13
Tests of
Boiler Materials
Metals are tested for strength in various ways as by taking
a sample of standard shape and subjecting it in testing ma-
chines to tension, compression, bending, sheering stresses. There
are various terms used in testing and the definitions, as here
given should be carefully noted.
In testing, what is a 'specimen"?
Ans. A portion of the whole submitted to tests to determine
the qualities or physical properties of the remainder.
What are the various tests that should be made on
boiler materials?
Ans. 1, Tensile; 2, compression; 3, transverse; 4, shearing;
5, tortional; 6, hardness; 7, cold bending; 8, homogeneity.
Define bending stress.
Ans. A force acting upon some member of a structure tending
to deform it by bending or flexure; the effect of this force.
causes bending strain on the fibers or molecules of the material
of which the part is composed.
An instance of pure bending stress is given by pulling on the end of
a lever, which tends to deflect it while performing work.
146
Tests of Boiler Materials
Define compression.
Ans. To press or push the particles of a member closer
___||_
W
<1″TO 13″ RAD-
FIXED END
b
THICKNESS SAME AS BOILER PLATE
PARALLEL SECTION
NOT LESS THAN 9"

- 18"-
Fig. 1.—Standard specimen required for all tension tests of plate material.
Tension and bend test specimens shall be taken from the finished rolled ma-
terial. They shall be of the full thickness of material as rolled, and shall be
machined to the form and dimensions here shown, except that bend test speci-
mens may be machined with both edges parallel. One tension, one cold bend,
and one quench bend test shall be made from each plate as rolled. If any test
specimen show defective machining or develop flaws, it may be discarded
and another specimen substituted.
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Fig. 2.—Tensile test. The specimen R, is placed in the wedge grips a, b, c, d,
thus pulling it in tension between the fixed end and movable head of the
machine. The latter is connected with the scale lever G, upon which slides the
weight W, similar to an ordinary weighing scale. Two center marks L and F,
are punched on the specimen at a standard distance A, apart. In testing, the
pull on the specimen is gradually increased by moving W, to the left and the
dimensions A, and B, measured for each increase of load.
Tests of Boiler Materials
147
together, as, for instance, the action of the steam pressure in
a boiler on the fire tubes.
Define deformation.
Ans. Change of shape; disfigurement, as the elongation of
test piece under tension test.
L
Define factor of safety.
Ans. The ratio between the breaking load and what is selected
as the safe working load.
L
B
-A-
F
FRACTURE
•


F
A
Figs. 3 and 4.-Tensile test specimen before and after rupture showing reduc-
tion of section Blat break.
Thus, if the breaking load of a bolt be 60,000 pounds per square inch,
and the working load be 6,000 pounds per square inch, then the factor
of safety is 60,000÷6,000 = 10.
Define force.
Ans. That which changes or tends to change the state of a
148
Tests of Boiler Materials
•
body at rest, or which modifies or tends to modify the course
of a body in motion, as a pull, pressure, or a push; a force
always implies the existence of a simultaneous equal and
opposite force called the reaction.
Define load.
Ans. The total pressure acting on a surface.
Thus, if an engine piston having an area of 200 square inches be
subjected to a steam pressure of 150 lbs. per square inch, then the
load, or total pressure on the piston is 200 X150=30,000 lbs.

Qumrana e In
Omi
и
R
F
M
S
q
Fig. 5.-Compression test. The specimen R, is placed between the two plates
M, and S, and a compression stress of any intensity applied by moving the
weight W, on the lever G. In testing, as the load is gradually increased, the
changes in dimensions A, and B, are noted and result calculated in a manner
similar to that explained for the tensile test, fig. 2.
Define member.
Ans. A part of a structure as a brace, rivet, tube, etc.,
subject to stresses.
Define modulus (or Coefficient) of elasticity.
Ans. The load per unit or section divided by the elongation
or contraction per unit of length.
•
Tests of Boiler Materials
149
Within the elastic unit, when the deformations are proportional to
the stresses, the modulus of elasticity is constant, but beyond the elastic
limit, it decreases rapidly. In wrought iron and steel there is a well
defined elastic limit, and the modulus within that limit is nearly
constant.
M
Define modulus of rupture.
Ans. A value obtained by experiment upon a rectangular
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Fig. 6.-Transverse test. The specimen R, is placed on two supports M and S, and
a load W, applied at the mid point as shown. The deflection or amount of
bending for any load is indicated with precision by the multiplying gear, LF.
In testing, the weight W, is gradually increased and deflection noted till the
breaking load is reached.
S
bar supported at the ends and loaded at the middle, substi-
tuting results in the formula
3 Pl
2 bd2
in which P-breaking load in pounds;
l, b, d=length, breadth and depth respectively in inches.
150
Tests of Boiler Materials
Define permanent set.
Ans. When a metallic piece is stressed beyond its elastic
limit, deformation occurs, the piece being either stretched,
crushed, bent or twisted, according to the nature of the strain.
This alteration in form is known as permanent set.

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DOUBLE
SHEAR
Figs. 7 and 8.—Single and double shear tests. The specimen is placed in
the holder and the stress applied. The cutter shears the metal in a single plane
for single shear and in two planes for double shear.
Tests of Boiler Materials
151
Define resilience.
Ans. The property of springing back or recoiling upon re-
moval of a pressure, as with a spring.
"Min
1
Without special qualifications the term is understood to mean the
work given out by a spring or piece, strained similarly to a spring,
after being strained to the extreme limit within which it may be
strained again and again, without rupture or receiving permanent set.

FIXED END
ELEMENT OF SURFACE BEFORE DEFLECTION
ELEMENT OF SURFACE AFTER DEFLECTION
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DEFLECTOR INDICATOR
Fig. 9.-Tortion test. The specimen is gripped in the head so that it cannot
turn and the indicator attached; this end free to turn on the support. Tortion is
applied by the weight, which twists the specimen in a clockwise direction, thus
an element of its surface is distorted from a straight line, to a spiral form, the
amount of distortion depending upon the intensity of the tortional force applied
and the resisting power of the metal. By attaching at the deflection end, a suit-
able scale, the amount of twist can be read in degrees. The results sought in
tortional tests are to determine the tortional elastic limit and ultimate tortional
strength. Since the strain varies over the sectional area, it cannot be expressed
as pounds per square inch, but must be stated as inch pounds. The value is
obtained by multiplying the pull applied by the lever arm by the distance
through which it acts. Thus if the weight be 100 pounds and the lever arm be
30 inches, then the tortional stress corresponding is 100x30 = 3,000 inch-
pounds. Again if the indicator register 20° on a 20-inch specimen the deflec-
tion in twist is stated as 20°÷20 inches = 1° per inch.
152
Tests of Boiler Materials
Define shear.
Ans. The effect of external forces acting so as to cause
adjacent sections of a member to slip past each other. When
so acted upon, the member is said to be in shear.
Define strain.
Ans. According to Wood, it is a name given to the kind of
alteration produced by the stresses.
The distinction between strain and stress is not always observed,
there being much confusion among writers as to these terms.
1/16"
GROOVE
FRACTURE
AT GROOVE
Figs. 10 and 11.-Homogeneity test. Made by grooving and fracturing
specimen.
Define stress.
Ans. 1. An internal action or internal force set up between
the adjacent molecules of a body when acted upon by forces.
2. The force or combination of forces, which produces a strain.
.

Tests of Boiler Materials
153
Define tensile strength.
Ans. The cohesive power by which a material resists an
attempt to pull it apart in the direction of its fibers, this
bears no relation to its capacity to resist compression.
·14 "DIAM.-
Define tension.
Ans. The stress or force by which a member is pulled; when
thus pulled, the member is said to be in tension.
"DIAM.
7/32" RAD.
.8" DIAM:"
ין
·3½"-
STANDARD THREAD

-14 IN. DIAM.-
Fig. 12.-Standard specimen required for tension tests of gray iron casting
material. The quality of the iron going into casting under specification shall
be determined by means of the above specimen, known as the arbitration bar.
The tensile test is not recommended, but in case it be called for, the bar as here
shown, shall be turned up from any of the broken pieces from the transverse
test. The expense of the tensile test shall fall on the purchaser.
Define ultimate strength.
Ans. The maximum unit stress developed at any time before
rupture.
154
Tests of Boiler Materials
Define yield point.
Ans. The point at which the stresses and the strains become
equal, so that deformation or permanent set occurs. The point
at which the stresses equal the elasticity of a test piece.
Shell Boiler Construction
155
Details of Shell
Boiler Construction
LAP.
CHAPTER 14
What is the distinguishing feature of shell boilers?
Ans. The use of fire tubes instead of water tubes.

RIVET
STRAPS
BUTT

RIVETS
-SHELL PLATE-
Figs. 1 and 2.-Single riveted lap joint and single riveted butt and double
strap joint.
What are sheets?
Ans. The boiler heads having circular holes for the flues or
tubes and to which they are respectively riveted or expanded.
What are the chief differences in locomotive boilers and
why?
Ans. They vary greatly in the shape of the furnace and the
location of the grate because of different kinds of coal available
in various localities.
156
Shell Boiler Construction
Upon what important detail of construction does the
strength of a boiler shell depend?
Ans. The longitudinal riveted joint of the shell.
Why?
Ans. Because the strength of the joint is always less than
the strength of the plate.


O
O
O
O
Figs. 3 and 4.-Butt joint with two covers.
What is the difference between a lap and a butt joint?
Ans. The plate ends overlap to form a lap joint and register
with each other to form a butt joint, as in figs. 1 and 2.
What is the objection to a lap joint?
Ans. The plate ends through which the rivets pass, being in
different planes, the pull is not direct but tends to twist the
plates, frequently causing them to bend.
Shell Boiler Construction
157
In designing a riveted joint what is the chief object in
view?
Ans. To so proportion it that it will be equally strong against
failure in all its parts.


о
о
о
о
о
о
Figs. 5 and 6.-Lap joint with cover plate or offset strap. It is safer than the
plain lap joint, but not as good as the butt joint with double strap.


Figs. 7 and 8.-Effect of pull on lap joints and butt joints with one cover plate.
What is the difference between centers of adjacent rivets
in the same row called?
Ans. The pitch. See fig. 9.
What is diagonal pitch?
Ans. That pitch where there are two or more rows of rivets,
the distance between the centers of diagonally adjacent rivets.
See fig. 9.
158
Shell Boiler Construction
What is back pitch?
Ans. The distance between the center lines of any two
adjacent rows of rivets. See fig. 9.
What is the difference between single and double shear?
Ans. Single shear occurs in one plane as in a lap joint, and

BACK PITCH-
PITCH
DIAGONAL PITCH
Fig. 9.-Double riveted butt joint, illustrating pitch, diagonal pitch and back
pitch.
double shear in two planes as in a butt and double strap joint.
See figs. 10 and 11.
What is the advantage of double shear?
Ans. It is twice as strong as single shear.
In practice it is taken as 134 to allow for imperfection of construction.
Shell Boiler Construction
159
What is the efficiency of a riveted joint?
Ans. The ratio which the strength of a unit length of a
riveted joint has to the same unit length of the solid plate.
SINGLE SHEAR
How does the efficiency of a riveted joint increase?
Ans. It increases as the rivet diameter and pitch is increased.

IA
M
Figs. 10 and 11.-Lap, and butt and double strap joint, illustrating respectively
single and double shear.
***
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We
AROMAT
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****
DOUBLE SHEAR


····
B
C
ΙΑ
D
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.....
18.
A
B'
c'
Fig. 12.-Single riveted lap joint, illustrating element of the seam to be con-
sidered in determining the strength of the joint. The shaded portion ABCD is
the element; its equivalent A' BICI DI may also be considered as an element.
160
Shell Boiler Construction
There is a practical limit to this owing to mechanical difficulties
encountered.
What basic consideration determines the strength of a
riveted joint?
Ans. It depends upon whether the plate or the rivets be the
stronger.

Figs. 13 and 14.-Failures of riveted joints; fig. 13, fracture between rivets;
Fig. 14, split, and double shear between rivets and edge of plate. The first is
caused by the rivets being too close together, that is, not enough metal in the
plate between rivet holes, and the second is due to insufficient metal between
rivet holes and edge of the plate.
What is a ligament?
Ans. The metal between tube holes.
Shell Boiler Construction
161
What are its dimensions?
Ans. Length = pitch-2Xtube radius. Its thickness = thick-
ness of tube sheet.
How are flat surfaces strengthened and why?
Ans. All flat surfaces must be stiffened or supported by stays
or braces, otherwise the steam pressure would bulge them out-
ward and tend to make them spherical or cylindrical in shape.
What is the difference between a brace and a stay?
Ans. The chief difference is in size, that is, a brace is a large
stay.
Into what two classes may all reinforcing members be
divided?
Ans. They may be classed as independent and connecting
members.
Stays
What is a stay bolt?
Ans. A metallic pin or rod, used to hold objects together
and generally having screw threads cut at one end, and some-
times at both, to receive a nut, as in fig. 15.
How are boiler plates tapped so that a threaded bolt or
stay will properly screw into both plates without strip-
ping the threads?
Ans. By the use of a long or stay bolt tap which threads both
plates in one operation, as in figs. 16 to 18.
•
162
Shell Boiler Construction

Fig. 15.-Stay bolt, consisting of a threaded length of rod with a nut at each
end, or a forged head at one end and a nut at the other end.

REAMER
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-TAPER-
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BOILER
PLATES
-TAPER
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-SHANK

SHANK

SHANK
Figs. 16 to 18.-Stay bolt tap, showing method of using and illustrating how
both plates are tapped in one operation so that the bolt will thread into both
plates without interference.
Shell Boiler Construction
163
What thread is used for stay bolt taps?
Ans. All sizes of stay bolt taps have 12 threads to the inch,
the approved form being the U. S. standard; the "V" thread
was formerly sometimes used.
What diameter of a screwed stay is taken in calculating
its strength?
Ans. The least diameter. »
100
For a continuous thread, this is at the bottom of the thread, and
at the middle section of turned stays.

42 THREADS
PER INCH
-TURNED DOWN SECTION
LEAST
DIAMETER
Fig. 19.-Riveted screw stay or so called stay bolt. The standard sizes vary from
3/4 to 1/2 ins. in diameter and all have twelve threads per inch.

Fig. 20-Hollow or drilled riveted screw stay.
What are riveted stays?
Ans. Stays in which the threaded ends are riveted instead
of having a nut at each end.
164
Shell Boiler Construction
Describe a riveted stay as used on the sides of the fire
box in vertical and locomotive boilers.
Ans. It consists of a rod threaded at the ends and turned
down along the middle section to a diameter slightly less than
that of the root of the threads, as in fig. 20.
Why slightly less than that of the root of the thread?
Ans. So that in passing the bolt between the sheets, the re-
duced diameter of the body will pass through the threaded hole
in the sheet.
in

UNE CQUAL EXPANSION OF PLATES
NORMAL
POSITION
OF STAY
DISTORTED
-OR- BENT
POSITION OF STAY_———
INDICATIONL
OF CRACK
W
Fig. 21.-Why screwed stays sometimes break. The inner plate being exposed
to the intense heat of the furnace expands more than the other one, hence a
see-saw movement is set up with changes in temperatures. The continued bend-
ing action tends to crystallize the metal in time and cause it to crack. By drill-
ing holes as shown, an extensive crack will be indicated by a leak or blow
through the hole-provided the hole has not become closed by dirt and
corrosion: In the figure the dotted lines show normal or straight position of
the stay, and the sectional view the bent position.
CRACH
What is the object of drilling holes through the ends of
screwed stays, as in fig. 20?
Where is the break most likely to occur?
Ans. Near the plate.
Ans. To indicate by a leak through the drilled holes a break
in the stay and its location. See fig. 21.
Shell Boiler Construction
165
Why do screwed stays sometimes break?
Ans. Because of unequal expansion between the outer and
inner plates the stays are bent back and forth each time this
occurs.
……………
Where does the break occur and why?
Ans. Usually close to the outer sheet, because the inner sheet
is generally thinner than the outer sheet and therefore holds
the end of the stay less rigidly. See fig. 21.

KOMNATULALATUITAMIN
till!!!
WAPBA
Fig. 22.-Spindle stay bolt taps with threaded spindle. The taps are threaded
externally and internally in a certain definite relationship so that continuity of
lead from one tap to the other is positively maintained regardless of the dis-
tance between the taps. This construction insures the tapping of a continuous
thread in the two boiler sheets where the stay bolt is to be located. The dis-
tance between the sheets may be anything within the limits of the spindle.
What precaution should be taken with drilled stays?
Ans. The holes should not be allowed to become closed by
corrosion.
1
What is a socket stay?
Ans. A so-called stay bolt consisting of a rod and socket.
See fig. 23.
Describe the placement of a socket stay bolt.
Ans. The socket is placed between the plates to be stayed
and the rod threaded through the plates and socket, and the
ends riveted.
166
Shell Boiler Construction
How is the stress distributed in a Gusset stay?
Ans. The tension is not uniform but is greater near one edge.
What is a palm stay?

SOCKET.
Fig. 23.-Socket stay or so called socket bolt. The socket acts as a strut and holds
the plates at a proper distance apart.

COPPER WASHERS
Fig. 24.—Stay rod or through stay, especially adapted to short boilers of large
diameter. The most common and simple form is a plain rod threaded at the ends.
The rod passes through the steam space and the ends are fastened to the heads.
The length is adjusted in various ways, the simplest being by nut and washers
as here shown. The copper washers prevent abrasion of the plates by the nuts
and act as packing in securing a tight joint. In place of the nuts the rod is some-
times bolted to angle irons which are riveted to the heads. In this case, turn
buckles are used for adjusting the length
Shell Boiler Construction
167
Ans. A round rod having forged on one end a plate or "palm"
and a thread and nut connected at the other end, as in fig. 35.
What is a stay rod or through stay?
Ans. A plain rod 14 to 22½ ins. in diameter having nuts
and washers for fastening the ends to plates.

Fig. 25.-Turn buckle used for adjusting the length of stay rods or through stays
when the latter are bolted to internal angle irons instead of passing through the
shell as in fig. 24.


Fig. 26.-Stay tube ends. It must be evident that where both ends are threaded
one end must be of larger diameter than the other to allow inserting the tube.

20
Figs. 27 and 28.-Diagonal stay bent to form from a flat steel plate.
168
Shell Boiler Construction
Where are they used?
Ans. Chiefly in marine boilers of the Scotch and Clyde types.
Why?
Ans. These boilers being short and of large diameter, the
considerable amount of flat surface in the heads not reinforced
by the tubes is conveniently stayed with through stays without
rendering the interior inaccessible.
Why are large copper washers used?
Ans. They prevent abrasion of the plates by the nuts and
act as packing in securing a tight joint. See fig. 24.

EYE ENDS
Fig. 29-Diagonal stay with eye ends. It is attached to the boiler angle irons
and pins.

Figs. 30 and 31.-Diagonal stay with forged ends.
Shell Boiler Construction
169
How far apart should the stays be spaced and why?
Ans. At least 14 ins. so that a man can pass between them.

✪ ◊ e
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Fig. 32.-Gusset stay consisting of a flat piece attached diagonally to the shell
and head by angle irons. Because of the character of the stress coming on a
gusset stay, it should be proportioned for a larger factor of safety than for or-
dinary diagonal stays.

االذا
Figs. 33 and 34.-Crow foot stay, consisting of a rod with forked end, attached
by a pin to a V shaped end with palms or so called crow foot, the palms of
which are riveted to the flat plate to be stayed.
170
Shell Boiler Construction
What is a stay tube?
Ans. A thick tube with threads on the ends, one end being
larger than the other so that the tube may be slipped through
the large hole. See fig. 26.

u
Fig. 35.-Palm stay, so called because it has a palm like plate forged at the
end. Since the threaded end passes through the head obliquely, two diagonally
cut washers are used as connectors between the nuts and plate.

DO
DO
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©
Figs. 36 and 37.-Jaw stay. This type of stay is used in connection with T
irons, riveted to the head.
These tubes are practically obsolete because of many tests showing
that the holding power of expanded tubes is more than is necessary to
support the pressure coming on the plate.
What are Gusset stays?
Ans. Pieces of plate iron secured to the boiler front or back.
near the top or bottom by means of angle irons, as in fig. 32.
Shell Boiler Construction
171
What is a jaw stay?
Ans. A round bar having jaws forged at one end and a flat
plate at the other inclined at the proper angle for riveting to
the boiler shell, as in figs. 36 and 37.
The jaw end is attached by a pin to a T iron which is riveted to
the head.


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Figs. 38 and 39.-Staying of head in tubular boiler with steel angles.
What is a steel angle stay?
Ans. Two lengths of steel angle riveted together forming a
T shape piece and riveted to the plate. See figs. 38 and 39.
Where are they used?
Ans. They are used for staying the segment of heads above
the tubes on boilers not over 36 ins. in diameter and limited
to 100 lbs. pressure.
172
Shell Boiler Construction
What is a crown or roof bar?
Ans. It consists of a solid bar or made up of two plates
welded together at the ends and having a depth of about 4 to
6 ins. and proper thickness to support the load coming on it.
Either bolts or rivets may be used to keep the plates which form the
girder from spreading.
What is the application of crown or roof bars?
Ans. They are used for supporting the flat tops of fire boxes

SLING STRAPS
ė
CROWN BAR
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Fig. 40.-Detail of crown bar reinforced by sling straps. The sling stays are con-
nected to the girder and to an angle iron or T iron, which is riveted to the shell.
The angle iron stiffens the shell. In design, the crown bar should be strong
enough to support the crown sheet independently of the sling straps.
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and combustion chambers, especially in locomotive and marine
boilers, as in fig. 40.
What is the application of radial stays?
Ans. They are used chiefly in locomotive boilers in which
the fire box crown sheet is arched.
Shell Boiler Construction
173
How are they arranged?
Ans. Radially to the curvature of the two plates which they
connect. See fig. 43.

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Figs. 41 and 42.-Details of crown bar construction supported by side plates.
The bar is usually made up of bar plates having a depth of from 4 to 6 inches.
and a thickness of 5% to ¾ inches. If 8 inch stays be used, the distance between
the plates is usually 1 inch. The plates are forged so that they take a bearing
by means of feet on the edges of the side plates and support the furnace top
by bolts which pass between the two strips and have a nut resting on a washer
which spans the strips. The ends of the bars which rest upon the side plates
should be carefully fitted to make a good bearing, and the area should be
sufficient to prevent crushing. The distance between the crown sheet and the
guides should be at least 1½ inches to insure good circulation and facilitate
cleaning.

Fig. 43.-Detail of radial stays as connected to a cruved or arched crown sheet.
174
Shell Boiler Construction
Vertical Tubular Boilers
Name two types of vertical shell boilers.
Ans. The through tube and the submerged tube.


3
Top
Figs. 44 to 46.—Details of corner angles or T braces.
O
O
O
O
O
O
O
RADIAL T BARS
O
O
O
O
O
O
O
A

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Fig. 47.-Radial T bars for fastening stays to heads,
Shell Boiler Construction
175
O
Describe a through tube vertical boiler.
Ans. An outer cylindrical shell encloses the water and steam
space. Within this shell is a smaller cylinder extending about
one-third way up which forms the furnace and combustion
chamber and ash pit. The cylindrical furnace is flanged out at
the bottom until it meets the outer shell, dispensing in this way,
with a lower head. In one side it flanges to the shell to form an
opening for furnace door; the top is flat and into which are
expanded a multiplicity of vertical tubes, the upper end of

ANGLE BAR
CHANNEL BARS
O
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Fig. 48.-Angle and channel bars for through stay connections.
which are expanded into a similar flat surface at the top of the
shell. These flat surfaces are called respectively the lower and
upper tube sheets.
How is the cylindrical furnace fastened to the outer
shell?
Ans. By a proper number of stay bolts.
What would be the tendency in the absence of these
stay bolts?
Ans. The cylindrical furnace would tend to collapse.
176
Shell Boiler Construction
-HEAD-
SHELL
LOTU
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Figs. 49 to 56.-Methods of fastening stays. Figs. 49 to 52, head fastenings; figs. 53 to 56 shell fastenings.
1


Shell Boiler Construction
177
What is the construction of submerged tubes of vertical
boilers?
Ans. The top head of the shell is riveted to a conical shaped
submerging chamber called a "cone" of sufficient depth that
the upper tube sheet attached to the lower flange of the cone
is submerged below the water level.
What is the objection to this arrangement?
Ans. It complicates the construction and renders the upper
tube sheet less accessible.
The advantage of the submerged tube idea in the author's opinion
is in general greatly overrated except in the case of poorly designed
through tube boilers attended to by an ignorant operator, or pur-
posely forced.
Where is a fusible plug placed?
Ans. In an outer tube heavier than the others and located
at a distance not less than 3 the distance of the length of the
tube from the bottom tube sheet.
How is the fusible plug attached to the tube?
Ans. It is screwed into the tube.
ů
Are fusible plugs reliable?
Ans. No, they are temperamental like spark plugs.
Why?
Ans. They crystalize with age which increases the melting
point, accordingly they should be renewed every year or at a
shorter interval.
Why are tube sheets thicker than shell plates?
Ans. They are subject to strains put on them by the expan-
178
Shell Boiler Construction
sion and contraction of the tubes. Moreover they must be thick
enough to have sufficient strength to expand the tubes into
the tube sheet without expanding the holes.
What data is stamped or placed on the name plate?
Ans. Such items as name of manufacturer of steel; its tensile
strength; name of manufacturer of boiler, boiler number, etc.
What is the difference in the pressure exerted on the
outer and furnace shells?
Ans. The outer is in tension and the furnace shell in com-
pression.
Which shell is the weaker of the two?
Ans. The inside shell.
Why are stay bolts used?
Ans. To prevent bulging or collapse of the furnace inward.
How about the number of stay bolts provided?
Ans. A large number of small stay bolts is better than a few
larger ones.
◊
How is a broken stay bolt detected?
Ans. If of the drilled type, a break is detected by leakage.
How many tube sheets has a vertical boiler?
Ans. A top tube sheet and a bottom tube sheet.
Shell Boiler Openings
179
CHAPTER 15
Shell Boiler Openings
Why are openings provided leading into the water and
steam spaces of shell boilers?
Ans. They are necessary for proper care and operation of
the boiler.
How are the openings classified?
Ans. They are divided into two classes known as: 1, major
openings, and 2, minor openings.
Name the major openings?
Ans. Man holes and hand holes.
What are the two classes of minor opening?
Ans. The steam openings and the water openings.
Name the steam minor openings.
Ans. 1, main outlet; 2, outlet for safety valve; 3, outlets for
auxiliary steam; 4, outlet for injector; 5, outlets for gauge
cocks; 6, feed water inlet; 7, blow off outlet.
How are hand and man holes located?
Ans. They are placed in such a position that accumulations
of sediment can be removed and that tools can be inserted for
180
Shell Boiler Openings

FRONT
TUBE
SHEET
11"X15"
IS
STAYS
STEAM NOZZLE
HANDHOLE
TUBES
MANHOLE
SHELL
Figs. 1 and 2.-Major and minor openings in a horizontal return tubular boiler.
SHELL
) --
STEAM
NOZZLE
FUSIBLE PLUG
REAR TUBE SHEET
HANDHOLE-
BLOW OFF PIPE-
12 C
cleaning boiler tubes and shell. Man holes are placed so that entrance can be had for
the examination and replacing of stays, braces, tubes and pipe connections.
Where is the man hole for a horizontal boiler usually placed?
Ans. In the top of the shell, or, for large boilers, in the head above the water line.
Where is the hand hole placed in horizontal tubular boilers?
Ans. In each head below the tubes and for vertical boilers they are placed opposite
the lower tube sheet and at the bottom of the water leg.

Shell Boiler Openings
181

FOR INJECTOR.
FOR FEED INLET
7
FOR GAUGE COCKS
FOR STEAM GAUGE
FOR MAIN OUTLET
FOR WATER GAUGE
R BLOW OFF
Fig. 3.-Minor openings in a ver-
tical boiler. In this type boiler the
fusible plug is tapped into one of
the fire tubes, being reached
through a hand hole at the low
water level.
What is the usual size of man
hole and how placed?
Ans. 11 x 15 ins. the longer
diameter being placed at right
angles to the axis of the shell.
What is the shape of the
opening?
Ans. Elliptical.
What is the effect of the re-
moval of the section of the
shell and what must be done?
Ans. It reduces its strength
and reinforcement must be used,
either by flanging over the shell
or by riveting on a collar around
the opening.
Why is only one or two bolts
sufficient for securing a hand
or man hole cover to the
boiler?
Ans. Because the steam press-
ure does not come on the bolts
but on the boiler plate, the bolts
serving merely to hold the cover
in place firmly against its gasket
when there i no internal press-
ure on the boiler.

182
Shell Boiler Openings
When a man hole is cut in a shell how is the shell rein-
forced?
Ans. By a forged steel ring fitted about the hole.
Fig. 4. Wrought steel manhole plate. There are two bolts hydraulically riveted
in position.
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Figs. 5 to 7.-Views of ordinary fire door, showing damper and baffle plate.
How is a tight joint secured on a hand or man hole?
Ans. By means of a gasket.
What is a steam dome?
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daytrid of had logi
beanol bule sidia
Billaddu on ad
Ans. A chamber on the top of a boiler. In plod od o ropoul
Javol 15to
of

Shell Boiler Openings
183
What is the object of a steam dome?
Ans. To get rid of some of the moisture in the steam.
illed
What is the present status of steam domes?
Ans. They are practically obsolete except on locomotive and
some special boilers.
COOKOUT SO
CHATTANOO
TENNU
MFG.CO
Fig. 8.-Furnace front and shaking grate assembly. On the furnace front is
shown large fire door with automatic safety latch, hinged ash door with ratchet
bar draft regulator, lever for shaking grates and saddle wedge for holding
grates in firing position. The grate assembly is made by fitting the parts together
without the use of bolts or pins. The shaking grate bars are supported in a
frame made up of a right and left side bearing bar and a front and rear bearing
bar. The front bearing bar is bolted to the furnace front. The balance of the
grate assembly in the furnace is made without bolts.
What size opening is cut in the shell to communicate
with the dome?
Ans. Some manufacturers place the upper man hole in the
dome, while others make the opening just large enough to
pass the steam at the proper velocity.
184
Shell Boiler Openings
What is the usual proportion of a steam dome.
Ans. The diameter and height is usually about one half the
diameter of the boiler.
I
Water Tube Boiler Construction
185
CHAPTER 16
Details of Water Tube
Boiler Construction
What is the main difference between a water tube boiler
and a shell boiler?
LARGE{


STEAM SPACE-
VOLUME OF WATER-
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Figs. 1 and 2.-Sensitiveness of shell and water tube boilers. The shell boiler
with its large steam and water spaces is less sensitive to sudden load changes
than the water tube boiler.
186
Water Tube Boiler Construction
Ans. The water is inside the tubes of a water tube boiler and
outside the tubes in a shell boiler, as in figs. 1 and 2.
With respect to the definitions, what is a shell boiler
sometimes called?
Ans. A fire tube boiler.
What are the methods of grouping the tubes in water
tube boilers?


图
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WATER LEVEL
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UNDER
DISCHARGE
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Figs. 3 and 4.-Sectional and non-sectional arrangement of the heating
surface.
Ans. 1, sectional, 2, non-sectional; as shown in figs. 3 and 4.
Of what does the tubular heating surface consist?
Ans. Either tubes or wrought pipe. See figs. 5 and 6.
Water Tube Boiler Construction
187
What minor openings are provided for the ordinary
horizontal tubular boiler?
Ans. 1, Two main steam outlets, one being for main steam
supply and the other for auxiliaries; 2, an independent outlet
for the injector only; 3, two outlets for water column connec-
13 BWG .095 IN.

7
LIN.
-1.315 IN.-
IIN. TUBE
IIN. PIPE
(STANDARD)
Figs. 5 and 6.-The difference between a tube and a pipe.
1.049 IN.
.133 IN

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tions; 4, opening for fusible plug; 5, inlet for feed water; 6,
outlet for scum cock; 7, outlet to blow off cock.
What should be noted about water column fixtures and
gauge cocks on vertical boilers?
Ans. They are usually connected direct to the shell.
188
Water Tube Boiler Construction
How about the main steam outlet on a vertical boiler?
Ans. There is usually only one main steam outlet, the safety
valve being attached to a branch connection from the outlet.
What should be noted especially about one of the outlets?
Ans. It should be remembered once and for all that a separate
outlet should be provided for the injector and steam should not be
taken for any other purpose from this outlet.
Why?
Ans. An injecter is a temperamental device and its opera-
tion will be unsatisfactory on sudden variations in steam
pressure.
What are nozzles?
Ans. Short flanged nipples.
Of what material should nozzles be made?
Ans. Of pressed steel.
How are boiler tubes listed and described?
Ans. From the outside diameter.
How are wrought pipes listed?
Ans. From the "nominal" inside diameter.
Thus a 1 in. wrought pipe is nearly 114 in. outside diameter while
a 1 in. boiler tube is exactly 1 in.
How are seamless tubes manufactured?
Ans. From solid billets by passing the billet heated white
hot through a piercing mill.
Water Tube Boiler Construction
189
What is the holding power of boiler tubes?
Ans. Experiments by Yarrow & Co. on steel tubes 2 to 212
ins. in diameter expanded into tube sheets, gave results ranging
from 7,000 to 41,715 lbs. Most tests give 20,000 to 30,000 lbs.
How are boiler tubes fastened to the tube sheets?
Ans. By expanding the metal of the tube against the tube
plate with a tube expander and then beading over the ends
with a beading tool.
How is the fire door openings constructed on vertical
boilers?
Ans. It is necessary to provide an opening through both
furnace plate and outer shell for firing, the simplest being the
ring construction, the plates being riveted against the ring and
caulked to give a tight joint.
Describe the door construction.
Ans. The door is made of cast iron and should be sufficiently
large to permit the convenient handling of shovel and slice bar
to the back of the fire.
What is the usual size of the door?
Ans. 12 ins. x 10 ins., varying up to 16 x 20.
How is the door protected thermally on the inside?
Ans. By a lining plate of cast iron which should be per-
forated so that air entering the damper of the door will be
divided into fine streams to cool the plate.
What is liable to happen to the lining plate?
Ans. It is likely to warp or crack by the intense heat.
190
Water Tube Boiler Construction

5/11/L
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Figs. 7 to 19.-Various forms of curved or bent tube as used in curved tube boil-
ers. They may be classed as: 1, single curve; 2, double curve; 3, triple curve,
etc.; 4, circular form as helix, flat and cone shaped spirals, etc.
25
Water Tube Boiler Construction
191
What shapes are given to the tubes or pipes?
Ans. They may be: 1, straight; 2, curved; 3, coiled; 4, closed
(porcupine), etc. See figs. 7 to 19.
Q Q Q Q
How are the tubes arranged?
Ans. They may be connected: 1, All in series; 2, all in
parallel; 3, sections in series; 4, sections in parallel; 5, sections
in series parallel. See figs. 20 to 25.

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Figs. 20 and 21.-Series connection, showing electric dry cells connected
in series and arrangement of pipes joined by return bends.
What positions are given to the tubes?
Ans. They may be: 1, horizontal; 2, inclined; 3, vertical. See
figs. 26 to 28.
How are tubes classed with respect to circulation?
Ans. As: 1, up flow; 2, down flow; 3, over discharge (priming
tube); 4, under discharge (drowned tube); 5, directed flow
(double tube). See figs. 29 to 33.
192
Water Tube Boiler Construction
What are the essential parts of any water tube boiler no
matter how complex may be its construction?
Ans. The parts necessary are: 1, steam-water drum; 2,

Q
fr
19 (1)
t
H
11
+
HEADERS-
In
cα
Of a a ∞ a - ā
•HH
-0--0
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ODG
Figs. 22 and 23.—Parallel connection, showing electric dry cells connected
in paralle!, and similar arrangement of tubes expanded into two headers.
oofed
IN PARALLEL
OGD
Oo
FO
HM


PIPES
IN SERIES
SERIES PARALLEL
Figs. 24 and 25.-Series parallel connection, showing electric dry cells
connected in series parallel, and similar arrangement of pipes tapped
into headers; here only two coils are shown and they are connected to headers
by pipes threaded R and L.
Water Tube Boiler Construction
193
HORIZONTAL
HHHHI
=
Figs. 26 to 28.-Inclination of the heating surface showing tubes in horizontal,
inclined and vertical positions.
-Ō
INCLINED

=
UP FLOW
20
oaż
·
VERTICAL



تميمة
شتم
eetca
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Fig. 29.-Circulation principles: 1, illustrating up flow.
50
194
Water Boiler Tube Construction

>==
S
DOWN FLOW
020==6=
cer
INNER TUBE
a sad
Fig. 30.-Circulation principles; 2, illustrating down flow. In construction,
non-return valves are provided to prevent reversal of flow-
not shown.
تمع
CIRCULATION
0:00
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W
W
ÿÿÿÿ:/ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
Fig. 31.-Circulation principles: 3, illustrating directed flow (due to Field
drop tube) and sometimes in the so-called "porcupine" type boiler as here
shown the heating surface is composed of tubes closed at one end and the
circulation "directed" by means of a smaller inner tube through which the
relatively cold water flows and returns through the larger tube. In the authors
opinion no good for various reasons.
Water Tube Boiler Construction
195
sometimes separate water drum; 3, down flow tubes; 4, lower
header; 5, up flow tubes; 6, sometimes upper header; 7, feed
water heater; 8, sometimes super-heater; 9, grate; 10, ash pan.
See fig. 34.
How are these elements assembled?
Ans. Into one unit by means of suitable fittings and connec-
tions and the assembly placed in an insulated casing.
UNDER DISCHARGE
OVER DISCHARGE


DROWNED
TUBE
O
BAFFLE
O
Figs. 32 and 33.—Circulation principles: 4, illustrating under discharge
(drowned tube) and over discharge (priming tube). In the latter method a
baffle plate is necessary to protect the outlet from spray especially in the
absence of a dry pipe.
What is the construction of a non-sectional boiler?
Ans. It consists essentially of a mass of tubes expanded in
parallel into two headers which connect at the ends of a com-
bined steam and water drum, as in fig. 35.
What is the advantage of the in parallel arrangement
of tubes?
Ans. All the tubes are accessible for cleaning.
196
Water Tube Boiler Construction

MAIN SUPERHEATED STEAM
OUTLET TO ENGINE
VALVE
Jage
N
BY
PASS
SURE AM
KAST
EASYC
WIKSTOWER DAS
ONE
SLEEDER SUPER HEATER
K
RGVEIKATO
DE
НД
G
SATURATED STEAM OUTLET
FOR AUXILIARIES
DRY PIPE I
FEED DISTRIBUTER
GRATE
34044
UP FLOW!!
UP FLOW!! PIPES
ASH PAN-
ROXYDABRAS«
STEAM AND
WATER DRUM
FEED WATER
HEATER
DOWN
FLOW
E
CHECK
VALVE
F
MUD DRUM.
INSULATING
CASE
PUMP
Fig. 34.-Elementary water tube boiler showing essential parts. In operation, feed water discharged by the
feed pump A, enters the feed water heater at B, and is raised usually to the boiling point in traversing the
heater. It is discharged into the drum through the feed distributer C, with minimum disturbance.
The ideal feed is constant and regulated to correspond with the steam demand.
Water Tube Boiler Construction
197
What is the construction of a sectional boiler?
Ans. The heating surface is divided into a number of sections.
1, each section consisting of a few tubes in parallel expanded
into small headers; or 2, a few pipes joined in series by return
bends, and connected to a header or direct to the drum. Details
of construction shown in figs. 36 to 40.
What is the advantage of the parallel arrangement?

+
O
•O
0.0
DOD
"/////
HEADER
Fig. 35.-Detail of header for non-sectional arrangement of the tubular heat.
ing surface.
Ans. The tubes are accessible for cleaning, especially im-
portant when operated with impure feed water. Also easy re-
placement as indicated in fig. 36.
What should be noted about the series arrangement?
Ans. Since the tubes are not accessible for cleaning, the series
arrangement precludes the use of impure feed water.
198
Water Tube Boiler Construction
What advantages have sectional over non-sectional
boilers?
Ans. The sectional boiler can be more easily transported
than the non-sectional type over difficult routes because it can
be knocked down into a number of comparative light units.
The sectional construction avoids the use of stay bolts.

)
(0
Ha
ALB
QUE.
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!!!!
VEN
Fig. 36.-Sectional headers showing replacement of a tube accomplished with.
certain precautions without waiting for boiler to cool down.
Moreover a tube or pipe failure is easily repaired by removing the
section. However in the case of expanded tubes in a non-sectional
boiler, the headers are arranged with openings opposite the tube ends
so that any tube may be removed.
What should be noted about boilers with curved tubes?

Water Tube Boiler Construction
0199
guontis
nfocaly
Ans. Various curves are employed to secure certain advan-
tages in construction.
contus quite
t
bpha Smirnoff
Tenaga alan A
What results are obtained by the use of bent tubes?
Ans. The results obtained are: 1, provision for expansion
and contraction; 2, longer tube length; 3, flexible disposition
of the heating surface:
4, in large boilers one
man hole to be removed
instead of individual
tube hand hole plates
for cleaning; 5, ease of
making repairs depend-
ing on the design; 6,
curved tubes designed
for over discharge give
a large space above the
grate, thus improving the
combustion efficiency.
Fig. 37.-Detail of sectional header showing
construction.
Under what condition
is provision for ex-
pansion and contrac-
tion especially im-
portant?
Ans. For operation
under forced draught.
What is the advantage
of longer tubes?
Ans. It reduces the
number of expanded
nu avd
joints.

200
Water Tube Boiler Construction
What is the advantage of flexible disposition of the
heating surface?
no/Toulait ni
Ans. In special cases the heating surface may be suitably
located without mechanical difficulties to give good circulation.
707
[10
What is the point with respect to larger boilers having
one man hole?
Ans. The drum is of such size that a man can enter through
the man hole and gain access to any of the tubes for cleaning.
haubivilni to Ban
af
ofod tail stor
Mopanimalo pol
Longly or unm
Ro
Figs. 38 to 40.-Details of sectional header hand hole plate. The oval shape of
plate permits removal.
What should be noted with respect to straight and
curved tubes?
Ans. A straight tube is more easily cleaned than a curved tube.
How does ease of repair depend upon design?
Ans. In some boilers any tube may be removed without dis-
turbing the others, whereas in some other tube arrangements
it is necessary to start at the beginning of the row and remove
all tubes up to the one damaged.
CE
Water Tube Boiler Construction
201

HUUTORIHUILÍ
……………
DUBUI
410141
SHINIHHHHHPOLLA
WATER LINE
LARGE AMOUNT
OF WATER
SLOW RESPONSE
NO WATER
LINE
PUMP
SMALL AMOUNT
OF WATER
QUICK RESPONSE
WATER
LPREMILIULEMIHMI
GOFO
STEAM
ODESYOBJED LORETRE 1
LANEY
wwwww
コ
​BURNER
Figs. 41 and 42.-Difference between a boiler and a generator. Fig. 41, boiler; fig. 42, generator.
or "flash boiler".
What is the advantage of curved tubes designed for over discharge?
Ans. This arrangement gives a large space above the grate which improves com-
bustion efficiency.
What is the object of tubes arranged in series parallel?
Ans. This arrangement is found in some large multi-drum boilers.
202
Water Tube Boiler Construction

A pa
Amy, ASUS
رب
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DIRECT
6xx
a
ad
Coo
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a
KERTOA TESCO BANJOJ
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BAFFLED
W
Figs. 43 and 44.—Combustion principles, illustrating direct draught and baffled draught. Evidently with
direct draught there is more or less short circuiting of the hot gases rendering portions of the heating surface
correspondingly less effective, on the other hand, baffles, especially of the horizontal type here shown become,
in time, coated with accumulation of ashes, etc., necessitating frequent cleaning.
It lends itself to very large boilers, the unit virtually comprising several boiler units com-
bined into one.
What is a porcupine boiler?
Water Tube Boiler Construction
203
HEADER OR
WATER LEG
FYLL
LONGITUDINAL DRUM

Cano-a-
TUBES
IN PARALLEL
1
RETURN TUBES
Fig. 45.—Elementary non-sectional boiler with longitudinal drum consisting
of drum, two headers or water legs and mass of tubes in parallel.
TRANSVERSE DRUM
HEADER OR
WATER LEG

MOONA
Fig. 46.-Elementary non-sectional boiler with transverse drum, and return tubes.
Since only one header is connected to the drum evidently some means of
completing the path for circulation must be provided, hence the return tubes.
204
Water Tube Boiler Construction

RAND L
1% DOWN FLOW
1½ DOUBLE EXTRA HEAVY HEADER
OCE
L H.
THREAD
ALL PIPE STANDARD
" WROUGHT PIPE
EXCEPT AS
OTHERWISE MARKED
2 x 2 ANGLE IRON
-22″-
-8 H. THREAD'
'1½½"DOUBLE EXTRA
HEAVY HEADER
¥4” EXTRA HEAVY
·LEGS PLUGGED AT
UPPER END
L.H. THREAD-
GRATE 11″x 22"
STANDARD MALLEABLE
FITTINGS EXCEPT AS
OTHERWISE MARKED
½" EXTRA HEAVY PIPE
PIPE
EXTRA HEAVY CROSS
K½"EXTRA HEAVY
LEGS PLUGGED AT
UPPER END
SIOF VIEW SHOWING INNER UPFLOWS, FEED WATER
HEATER COILS, ETC.
RANDL
RAND
RANDL
STEAM OUTLET
ལ་
·FEED WATER INLET
"STACK OPENING
SIKKIM
L.H. THREAD
WATER GRATE
SIDE VIEW SHOWING OUTER UPFLOWS, SUPERHEATER,
FEED WATER HEATER COILS, DRUM CONNECTIONS and
SUPPORTING LEGS
Figs. 47 and 48.-Two side views of small sectional series pipe boiler designed and built by the author to
furnish steam for experimental purposes. The features of this design are ease and cheapness of construction,
water grate and furnace enclosed on three sides by water heating surface. It can be made up entirely of pipe
and fittings, though a lighter drum may be made by the use of a large tube with heads turned out of boiler
plate and properly stayed. The sections are made up of ½-inch pipe and return bends with r, and I, elbows
at the lower ends and are connected to upper heads by r, and I, nipples. There are 10 up flow sections, 8
inner sections as shown in fig. 47, and two side sections as shown in fig. 48. There are two super heater sec-
tions, one on each side (fig. 48). Proportions: Up flows 26.6 square feet; feed water heater 13.3 square
Water Tube Boiler Construction
205
feet; super heater 7.1 square feet; total heating surface 47 square feet; total length ½-inch pipe 212 feet;
grate area 1.92 square feet; ratio 1:25.4. Grate is made of extra heavy ½-inch pipe spaced 1% inches be-
tween centers. The case indicated in dotted lines is made of thin sheets iron lined with asbestos board.
Figs. 47 and 48.-Text continued.
Ans. A type having a tube sheet or vertical drum
into which are screwed or expanded a number of
tubes, the outer ends of which are closed and which
form the water tubular heating surface.
What may be said in favor of porcupine boilers?
Ans. Not much.
Why?
Ans. They are no good for the same reasons as
given for the Field drop tube type page 106, fig. 15.
Pipe Boilers
What is a pipe boiler?
Ans. One made of wrought pipe and malleable
fittings. As in figs. 47 and 48.
What are they usually erroneously called?
Ans. Water tube boilers.
↓
This mistake is due to ignorance or a desire to cover up
the fact that they are made of pipe instead of tubes. As
stated before by the author the fact that they are made
of pipe is no objection as some very excellent boilers are
made of pipe.
206
Water Tube Boiler Construction
What kind of pipe is used?
Ans. The wrought pipe used is made in sizes according to
the Briggs standard and are listed according to the nominal
diameter rather than the actual diameter, there being con-
siderable difference, especially in the smaller sizes. See table
on page 885 and 886.

MANUE
Fig. 49.—Circular form or helix curve bent tube vertical drum automobile type
boiler. This is a true coil, as distinguished from the so called coil boiler in which
the "coils" are made up of straight pipes connected in series by return bends.
This type boiler consists of a central vertical drum, surrounded by a number
of pipe coils which are connected to the drum at its extremities. The drum holds
a reserve of water, which, when the boiler is in operation, circulates through the
coils absorbing heat from the fire, and re-entering the drum at the top as water
and steam. The amount of water in the drum varies from three gallons in the
smallest size to eight gallons in the 24-inch boiler. Steam is taken from the
top of the drum and passed through a superheater before delivery to engine.
What weight of pipe is used?
Ans. Standard, but in some cases extra heavy.
Water Tube Boiler Construction
207
Describe a typical pipe boiler.
Ans. It is built up in sections, each section being composed
of a few lengths of pipe connected in series by return bends.
The lower end of each section is connected by a right and left
long nipple to a bottom header or side pipe, and the upper end
by a short right and left nipple to the drum, the left handed
thread connection being in the side pipe and drum.
What are the features of pipe boilers?
Ans. The material of which they are constructed is cheap
and easily obtained anywhere in case of repairs. They can be
shipped knocked down, facilitating transportation over difficult
routes, and are easily assembled by any pipe fitter of ordinary
intelligence; high steam pressure may be safely carried.
In the selection of a pipe boiler what are the points to
be noted?
Ans. 1, accessibility for repairs especially the location of the
7 and I connections which have to be reached to remove sections;
2, special fittings these are preferably avoided in design, espe-
cially for boilers used in remote places because of delay in
sending to factory for new parts in case of repairs; 3, provision
for cleaning; 4, construction of casing; 5, mud drum and blow
off; 6, lifting ring for connection to hoist tackle in installing.
What is a water grate?
Ans. It consists of a series of pipes connected close together
in parallel to a header at one end and to up flow elements at
the other as in figs. 47 and 48, also fig. 52.
The drawings on page 204 show a pipe boiler with water grate de-
signed and built by the author. In a recent test, steam was generated
at working pressure from cold water in 5 minutes from striking the
match in lighting the fire.
208
Water Tube Boiler Construction
NEM
* - • * •
WIJA
TO MEW QUE
MEN? Path Dát. Jag til Maaf:
C
2222222222222
DH
Figs. 50 and 51.-Almy Class E water tube, pipe boiler. It consists of a large number of pipes screwed into
upper and lower manifolds, and is composed of side and fore and aft sections. It also has a feed water heater
and steam dome. The top manifold extends across the front and along the sides of the boiler, and the bottom
manifold extends along the sides and across the back below the grates. Between these manifolds are the
tubes which form the heating surface. Along the front of the boiler extends a drum, which forms a water reser-
voir connected at the bottom with the lower manifold. At the top it is joined to a steam dome in which the
steam rises or separates from the entrained water. The feed enters the feed water heater at the top, from whence


Water Tube Boiler Construction
209
it passes to the bottom of the horizontal reservoir. It then flows through the large tubes into the lower manifold,
from which it passes to the tubes, and, becoming heated therein, enters the top manifold, as a mixture of steam
and water, flowing to the separator. The water from the separator falls to the bottom of the reservoir and con-
tinyes in the circulation circuit until evaporated.
Figs. 50 and 51.-Text continued.
What is the difference between up flow and
down flow boilers?
Ans. According to the way in which the water
passages are arranged the circulation may be
directed upward or downward.
Although most boilers work on the up flow prin-
ciple, Rankine puts up an elaborate argument in
favor of the down flow type. See fig. 30.
In what special type boiler is the down flow
principle used?
Ans. In flash boilers.
What is a flash boiler?
Ans. A boiler consisting of a series of coils of
steel tubing, water is supplied by a pump on the
engine which delivers the water to the top coil,
from whence it circulates through the other
coils, becoming heated in its descent and issuing
from the lower coil, as highly superheated steam.
See page 201, fig. 42.
What goes under the name of a “special”
boiler?
Ans. Any one of a multiplicity of types for
special service or hallucinations of the designers
not already treated upon.
Well, what are some of these "freaks"?
210
Water Tube Boiler Construction
Well, what are some of these "freaks"?
Ans. Among the multitude may be mentioned: 1, combined
flue and fire tube; 2, combined fire tube and water tube; 3,
combined shell and water tube; 4, combined shell, fire and water
tube or other special types not included in the list just given.
What (though it does not belong in this chapter) could
be said in favor of cast iron sectional alleged house
heating boilers?
Ans. Not much-in fact very little.
Why?
Ans. Where is the heating surface?
Principally in the chimney, regardless of the coal bills.

=0
رزر
TRA
950200
LREST
3=8
40
XHC
VENSKTOP WA
A
WATER GRATE
Fig. 52.-"Water grate." It consists of a series of pipes connected close to-
gether in parallel to a header at one end and to the up flow elements at the
other, thus avoiding sagging or burning out as experienced with ordinary
grates especially when forced. In early times water grates were tried out by
James Gurney and others. Figs. 47 and 48 show small boiler with water grate
as designed and built by the author.
INHH
**}* #
Strength of Boilers
211
CHAPTER 17.
P
Strength of Boilers
Strength of Shell
What must be considered in determining the strength
of a boiler shell?
Ans. It is necessary to consider: 1, steam pressure; 2, diam-
eter of shell; 3, thickness of shell, and 4, efficiency of the joint.
How much of the shell is considered in making the calcu-
lation and why?
How is the thickness of the shell expressed?
Ans. As a fraction of an inch.
Ans. A section of the shell one inch long is taken and its diam-
eter is expressed in inches because the steam pressure, as indi-
cated by the steam gauge, means the pressure acting upon each
square inch.
Give an example illustrating total pressure to which the
metal of the shell is subjected.
Ans. Consider a one-inch length of a shell 10 ins. in diameter
and suppose the lower half to be filled with concrete and
212
Strength of Boilers

A
....
STEAM PRESSURE
50 LBS. PER SQ. IN.
DIAMETER 10 INS
*
...
*.**.
CONCRETE
****
……..
LENGTH I IN.
!!!
BA
Ad
50 LBS
50 LBS.
250 LBS.
50 LBS
•``....
50 LBS
50 LBS
50 LBS
50 LBS
➡O 50 LBS.
M i j j
CONCRETE
250 LBS.
……
1.10.
50 LBS
..
Figs. 1 and 2.-Section of boiler shell, illustrating total pressure to which the metal of the shell is subjected.
the upper half subjected to a steam pressure of 50 lbs. per sq. in. as shown in fig. 1.
Since the shell is 10 ins. in diameter and 1 in. long, evidently the area of the concrete
surface exposed to the steam pressure is:
10 x 1 = 10 sq. ins.

Strength of Boilers
213
and as there is 50 lbs. steam pressure acting on each sq. in. the
total pressure on the concrete is:
50 X 10 = 500 lbs.
one half of this being carried by the metal of the shell at each
side, that is, the load on the metal is 250 lbs.
What would be the stress in the shell if it were 1 in. thick?
Ans. Its sectional area would be 1 x 1 1 sq. in. hence the
stress in the shell would be 250 lbs. per sq. in.
=
What would be the stress in the shell if it were only 1/4 in.
thick?
Ans. The sectional area would be 14 x 1 = 14 sq. in. and the
total pressure or load of 250 lbs. would be carried by only 14 sq.
in. of metal, hence the stress would be increased 4 times, that is,
the metal would be subjected to a stress of
250 ÷ 1/4 = 250 x 4
X 1000 lbs. per sq. in.
1
State the method of determining the stress in a shell in
the form of a rule.
Ans. Multiply steam pressure in lbs. per sq. in. by RADIUS
of the shell (in ins.) and divide by the thickness of the shell expressed
as a fraction of an inch.
What important factor remains to be considered?
Ans. The riveted joint.
Why?
Ans. Because the strength of the joint is always less than the
strength of the plate.
214
Strength of Boilers

P
~ 50 LBS.
50 LBS.
250 LBS.
50 LBS.
50 LBS.
CONCRETE
11 #
50 LBS.
What is the ratio of the
strength of the joint to
the strength of the plate
called?
Ans. The efficiency of the
joint.
Why is the joint weaker
than the solid plate?
=
Ans. Because part of the
metal of the plate is cut
away for holes for the rivets.
Fig. 3.-Half section of shell, illustrating efficiency of the joint.
Example.—If, as in fig. 3 the efficiency of the joint be 50 per cent
and the plate be ¼ in. thick, what is the stress on the metal at the joint?
The total pressure coming on the full plate section is 250 lbs. and
since the plate is 1/4 in. thick, the stress at P is:
250 ÷ 1/4 sq. in.
1,000 lbs.
Strength of Boilers
215
The efficiency of the joint being 50 per cent, the area of section J
will be one-half of P or
1½ of 1/4
=
=
18 sq. in.; hence
2,000 lbs.
=
stress along the joint
The same result is obtained by dividing the stress on the solid plate
by the efficiency of the joint, that is:
1,000 ÷ .5
2,000 lbs.
250 ÷ 18
=
←
RULES
1. To find the total pressure (load) to be carried by the shell.
RULE.—Multiply the gauge steam pressure in lbs. per sq. in. by the
radius of the shell expressed in inches.
2. To find the stress coming on the shell.
RULE.-Divide the total pressure (as found in 1) by the area of the
solid plate per inch length of longitudinal section, and by the efficiency
of the joint.
Expressed as a formula:
stress in shell
steam pressure X radius of shell
thickness of solid plate × efficiency of joint
Bursting Pressure
Upon what does the bursting pressure depend?
Ans. Upon: 1, Tensile strength of the shell; 2, thickness of the
shell; 3, radius of the shell; and 4, efficiency of the joint.
Considering a half section as in fig. 4, evidently if the internal
pressure acting on the shell indicated by the weights be sufficient to
bring a stress in the metal equal to its tensile strength, the shell will
be pulled apart or ruptured as shown, the rupture taking place at the
weakest section of the joint.
4
Example.—Thickness of solid plate ¼ in.; diameter of shell 10 ins.
efficiency of joint 50 per cent; tensile strength 60,000 lbs. per sq. in.
What is the bursting steam pressure?
216
Strength of Boilers
•
Equivalent thickness of metal for 50 per cent efficiency is:
14 X.5 % in. (that is, 50 per cent of ¼)
====
For 60,000 lbs. tensile strength per sq. in. g of this would be the
corresponding force necessary to rupture the joint, or
¼% of 60,000
7,500 lbs.
JOINT
ANGE
? LBS
BOILER
SHELL
? LBS.
=

2
? LBS
CONCRETE
? LBS
.***
? LBS
· 10.
71
Fig. 4. Half section of shell, illustrating bursting pressure. The concrete indi-
cates uniform distribution of pressure due to the weights.
That is, the total pressure necessary to burst the boiler is 7,500 lbs.
acting on the half section, and since this pressure is distributed over an
area of 5 sq. in. the equivalent steam pressure per sq. in. is:
7,500 ÷ 5 1,500 lbs.
Strength of Boilers
217
Accordingly the following rule:
1. To determine the bursting pressure.
RULE.-Multiply the thickness of the shell (expressed in inches or
fraction of an inch), by the efficiency of the joint and by the tensile strength
of the metal. Divide the product by the radius of the shell and the result
will be the bursting pressure in lbs. per sq. in.
Factor of Safety
What is the factor of safety?
Ans. The ratio of the bursting pressure to the working pres-
sure.
What do you mean by the working pressure?
Ans. The maximum safe pressure to which a boiler is sub-
jected.
working pressure
What determines the safe working pressure?
Ans. It is the maximum pressure to be carried on a boiler
consistent with the factor of safety employed in the design.
-
Example. The bursting pressure of a certain boiler is 500 lbs.
What is the safe working pressure for a factor of safety of 5?
bursting pressure ÷ factor of safety
5
500
*****
100 lbs. per sq. in.
The Working Pressure
Upon what does the working pressure depend?
Ans. The maximum pressure to be allowed at which it is con-
sidered safe to operate a boiler depends upon: 1. Tensile
strength; 2, thickness of shell; 3, radius of shell; 4, efficiency of
the joint; 5, factor of safety.
218
Strength of Boilers
Example.—What is the maximum allowable working pressure to be
carried on a boiler 50 ins. in diameter, tensile strength 60,000 lbs.
plates 3/8 in. thick, efficiency of joint 87 per cent, factor of safety 5?
A tensile strength of 60,000 lbs. corresponds to a stress of
60,000 × 3%
22,500 lbs.
3
8
in a ¾ in. plate per inch length of section, and for a factor of safety
of 5, the maximum load allowable on the solid metal of the shell is:
22,500 ÷ 5
4,500 lbs.
J
P
MAX. LOAD AT J =
pressure.
=

(60,000 x 38) x 87%
5
-25 INS-
WORKING PRESSURE 3,915-25=156.6 LBS.
Fig. 5.-Half section of shell, illustrating method of determining the working
3,915 ÷ 25
Considering the efficiency of the joint 87 per cent, this load must be
reduced to
=
87 per cent of 4,500 3,915 lbs.
not lbs. per sq. in. but the maximum allowable force or load tending
to pull the metal of the shell apart. Since this force is distributed over
the radius of the shell or 50 ÷ 2 25 ins. (that is, 25 sq. in. consider-
ing 1 inch length of shell) the maximum allowable working pressure is
(see fig. 5):
= 3,915 LBS.
*
V
1561½ lbs. per sq. in.
2
Strength of Boilers
219
Expressed as a formula the problem becomes
TXTXE
working pressure =
RX F
in which:
T = ultimate tensile strength stamped on shell plates in lbs. per sq. in.
t = minimum thickness of shell plates in weakest course, in inches.
E = efficiency of longitudinal joint or of ligaments between tube holes
(whichever be the least).
Rinside radius.
F = factor of safety, or the ratio of the ultimate strength of the
material to the allowable stress.
Thickness of Shell
After figuring the size of a boiler for a given capacity,
what is usually the first problem to solve?
Ans. To determine the proper thickness of the shell necessary
for safety.
Upon what does the thickness of the shell depend?
Ans. Upon 1: Working steam pressure; 2, radius of the shell;
3, efficiency of the joint; 4, tensile strength of the plate; 5, factor
of safety.
←
Example. What thickness of shell is required for a 50 inch boiler
suitable for 125 lbs. working pressure if the tensile strength of the
plates be 60,000 lbs. efficiency of joint 82 per cent factor of safety 5?
Radius of shell
25 ins.
K
50 ÷ 2
125
-=
The total pressure to be carried by the shell is equal to
radius X working pressure
25 X
=
3,125 lbs.
220
Strength of Boilers
Since the factor of safety is 5, the shell must be strong enough to
withstand 5 times this load or
5 X 3,125
15,625 lbs.
If the efficiency of the joint were 100 per cent and with 60,000 lbs.
tensile strength, the thickness of shell would be
15,625 ÷ 60,000
.26 ins.
R.
Now since the efficiency of the joint is only 82 per cent, the thick-
ness of the shell is:
.26 ÷ .82
*****
=
.317 or say 516 ins. (approx.)
THICKNESS =
=
J=82% OF P
TOTAL PRESSURE = 25 X 125 =3125

(25x125)×5
60,000:X:82 SAY:56
317
R
<TENSILE STRENGTH =
60,000 LBS.
Fig. 6.—Half section of shell, illustrating method of determining thickness of
shell.
Riveted Joints
Name two general types of riveted joint.
Ans. 1. Lap joints and 2, butt and double strap joints.
Strength of Boilers
221
Name the various types of lap joint.
Ans. 1. Single riveted; 2, double riveted; 3, cover plate.
Name the various types of butt and double strap joints.
Ans. 1. Double riveted; 2, triple riveted; 3, quadruple riveted;
4, quintuple riveted.
What is the difference between a lap and a butt joint?
Ans. The plate ends overlap to form a lap joint and register
with each other to form a butt joint, there being two straps to
form tie pieces in riveting.
What is the objection to a lap joint?
Ans. The plate ends through which the rivets pass being in
different planes, the pull is not direct, but tends to twist the
plates, frequently causing them to bend and sometimes result-
ing in an explosion.
In designing a riveted joint, what is the chief object in
view?
Ans. To so proportion it that it will be equally strong against
failure by all possible ways of breaking.
What should be noted about the shearing strength of
rivets of lap and butt joints?
Ans. In the case of a lap joint the rivet will shear at only one
section, whereas in the case of the butt and double strap joint
shearing of the rivet is resisted by two sections.
What is the efficiency of a riveted joint?
Ans. The ratio which the strength of a unit length of a riveted
joint has to the same unit length of the solid plate.
222
Strength of Boilers
How to Calculate a Riveted Joint
In calculating the strength of any form of riveted joint
upon what is the calculation based?
Ans. A unit length or element of the joint is taken because the
strength of the entire seam is the same as the strength of this
element.

¡A
D
***
MAR
....
www
MR
***
Ch
M
*****
W
*******
K
B
C
ΙΑ
ANN
***
*******
HAWA
<
****
B'.
Ic'
Fig. 7.-Single riveted lap joint, illustrating element of the seam to be con-
sidered in determining the strength of the joint. The shaded portion ABCD is
the element; its equivalent A'B'C'D may also be considered as an element.
How long is the element?
Ans. The length of the unit length considered depends upon
the arrangement of the rivets and is equal to the greatest pitch.
Why should no further length of the seam be considered?
Ans. Because the entire seam is composed of similar elements
having the same symmetrical arrangements of rivets and plate
material.
Strength of Boilers
223
In calculating any riveted joint what are the three things
to be considered?
Ans. 1, Strength of the plate; 2, strength of the rivet or rivets;
3, efficiency of the joint.
Example. The method of calculating riveted joints is illustrated
in this example by taking the simplest joint the single lap joint.
In fig. 7 ABCD is the element of the joint to be considered. Evi-
dently since R has been cut out of the plate for the rivet, the solid
metal of the plate left to resist the pull is:
M+S,
or since M + R + S is equal to the pitch:
Strength of plate
or, as expressed with the usual symbols:
Strength of plate
(P—d) T..
in which t = thickness of plate; P
T = tensile strength.
Similarly
thickness × (pitch — diam. of rivet) × tensile strength
-
=
=
pitch; d
strength of rivet
section area of rivet × shearing strength
or expressed as a formula:
---
=
=
(1)
diameter of rivet, and
strength of rivet
in which .7854 d² section area of rivet, and S
.7854 d² × S...
d2 X
(2)
shearing strength.
Now, if the tensile strength of the plate be say 60,000 lbs. per sq. in.
of section, and say, 40,000 lbs. per sq. in. of section for the rivet, then
Shearing strength of rivet
tensile strength of plate, or
40,000
60,000
=
S = 2/T....
Hence, substituting this value for S, in equation (2)
Strength of rivet .7854 d² × 2T = .524 ď² T …
(3)
(4)
224
Strength of Boilers
Now, for equal strength of plate and rivet the values obtained in (1)
and (4) for strength of plate and rivet must be equal, that is
t (P-d) T .524 d² T
or
t (P-d) = .524 d²
d2
(5)
The strength of the solid plate must be considered to determine the
efficiency of the joint. Evidently
Strength of solid plate
thickness × pitch × tensile strength = t PT (6)
Now, since efficiency of the joint strength of joint ÷ strength of
solid plate, and since strength of plate at the joint
rivet, then from equations (1), (4) and (6).
strength of the
=
Efficiency
or reduced to lowest terms
Efficiency
t (P―d) T
t PT
P-d
P
(
——
.524 d² T
t PT
524 d2
t P
(7)
Mention an item that has not been considered in the cal-
culations just given.
Ans. The strength of the plate against shearing between rivet
and edge of the plate.
How is this determined sometimes without calculation?
Ans. In practice failure is guarded against by placing the rivet
hole at a proper distance from the edge of the plate, which by
experience has been found to be about one diameter solid metal
that is, 11½ diameter from edge of plate to center of rivet hole.
What was the object of the foregoing calculation?
Ans. To illustrate the principles involved which if thoroughly
understood there should be no difficulty in applying them to the
more complicated joints.
Strength of Boilers
225
The American Society of Mechanical Engineers has made an
exhaustive study of the subject and in its boiler code has
formulated rules for calculating the various forms of joint,
which will now be given.

RIVETED JOINTS
b
Efficiency of Riveted Joints.-The ratio which the strength
of a unit length of a riveted joint has to the same unit length of
the solid plate is known as the efficiency of the joint and shall be
calculated by the general method illustrated in the examples
which follow:
P
Example.-Calculate a single riveted lap joint corresponding to the
specifications here given.
The following A.S.M.E. Boiler Code notation is used:
TS
tensile strength stamped on plate, lb. per sq. in.
t
thickness of plate, in.
thickness of butt strap, in.
pitch of rivets, in., on row having greatest pitch
d =
diameter of rivet after driving, in. diameter of rivet hole
α = cross-sectional area of rivet after driving, sq. in.
S = shearing strength of rivet in single shear, Ib. per sq. in.
=
=
According to
***********
A.S.M.E. Boiler Code
=
=
226
Strength of Boilers
S = shearing strength of rivet in double shear, lb. per sq. in., as given
in Par. 16
c = crushing strength of mild steel, lb. per sq. in., as given in Par. 15
n = number of rivets in single shear in a unit length of joint
N =number of rivets in double shear in a unit length of joint.
Example 1.-Lap joint, longitudinal or circumferential, single-riveted
.(fig. 8).
A = strength of solid plate = PXtXTS
B=strength of plate between rivet holes = (P―d)tXTS
C=shearing strength of one rivet in single shear=nXsXa

C
小
​-P↓↓
O
Fig. 8.-Example of lap joint, longitudinally and circumferentially single riveted.
A.S.M.E. Boiler Code.—Ultimate strength of materials used in computing joints.
12 Cast iron shall not be used for boiler and superheater mountings, such as nozzles,
connecting pipes, fittings, valves and their bonnets, for steam temperatures of over 450 deg.
Fahr.
14 Tensile Strength of Steel Plate. The tensile strength used in the computations for steel
plates shall be that stamped on the plates as herein provided, which is the minimum of the
stipulated range, or 55,000 lbs. per sq. in. for all steel plates, except for special grades having a
lower tensile strength.
Iron rivets in single shear.....
Iron rivets in double shear..
15 Crushing Strength of Steel Plate. The resistance to crushing of steel plate shall be
taken at 95,000 lb. per sq. in. of¸cross-sectional area.
16 Strength of Rivets in Shear. In computing the ultimate strength of rivets in shear, the
following values in pounds per square inch of the cross-sectional area of the rivet shank shall be
used:
Steel rivets in single shear..
Steel rivets in double shear..
38,000
76,000
44,000
88,000
The cross-sectional area used in the computations shall be that of the rivet shank after
driving.
•
Strength of Boilers
227
D=crushing strength of plate in front of one rivet=dXtXc
Divide B, C or D (whichever is the least) by A, and the quotient will be the
efficiency of a single-riveted lap joint as shown in hg. 8.
TS=55,000 lb. per sq. in.
t=¼4 in. =.25 in.
P=1% in. =1.625 in.
d=¹ in. =.6875 in.
a=.3712 sq. in.
s=44,000 lb. per sq. in.
•
12,890 (B)
22,343 (A)
c=95,000 lb. per sq. in.
A=1.625X.25X55,000=22,343
B=(1.625 .6875) .25X55,000 =12,890
C=1X44,000X.3712=16,332
D=.6875X.25X95,000=16,328
=.576-efficiency of joint

P
D
·
}
Fig. 9.-Example of lap joint, longitudinally and circumferentially double.
riveted.
Example 2.-Lap joint, longitudinal or circumferential, double-
riveted (fig. 9). ().
A=strength of solid plate=PXtXTS
B=strength of plate between rivet holes = (P—d) tXTS
C=shearing strength of two rivets in single shear=nXsXa
D=crushing strength of plate in front of two rivets=nXdXtXc
Divide B, C, or D (whichever is the least) by A, and the quotient will be the
efficiency of a double-riveted lap joint, as shown in fig. 9.
•
228
Strength of Boilers
TS=55,000 lb. ner sq. in.
t=% in.=.3125 in.
P=2% in. =2.875 in.
d=34 in. =.75 in.
a =.4418 sq. in.
s=44,000 lb. per sq. in.
0
1
31
26,523 (B)
49,414 (A)
Example 3.-Butt and double-strap joint, double-riveted (fig. 10).
{
c=95,000 lb. per sq. in.
A =2.875X0.3125X55,000=49,414
B=(2.875-.75) .3125X55,000=36,523
P
C=2X44,000X.4418=38,878
D=2X.75X.3125X95,000 =44,531
=.739=efficiency of joint

•
O
↓
Fig. 10.—Example of butt and double strap joint, double riveted.
A =strength of solid plate=PXtXTS
B=strength of plate between rivet holes in the outer row = (P―d) t×TS
C=shearing strength of two rivets in double shear, plus the shearing
strength of one rivet in single shear = NXSXa+nXsXa
D=strength of plate between rivet holes in the second row, plus the shear-
ing strength of one rivet in single shear in the outer row = (P-2d)
tXTS+nXsXa
Strength of Boilers
229
1
E=strength of plate between rivet holes in the second row, plus the crush-
ing strength of butt strap in front of one rivet in the outer row =
(P-2d) tXTS+dXbXc
F-crushing strength of plate in front of two rivets, plus the crushing
strength of butt strap in front of one rivet = NXdXtXc+nXdXbXc
G=crushing strength of plate in front of two rivets, plus the shearing
strength of one rivet in single shear = NXdXtXc+nXsXa
H=strength of butt straps between rivet holes in the inner row= · (P—2d)
26XTS. This method of failure is not possible for thicknesses of
butt straps required by these rules and the computation need
only be made for old boilers in which thin butt straps have
been used. For this reason this method of failure will not be con-
sidered in other joints.
Divide B, C, D, E, F, G or H (whichever is the least) by A, and the quo-
tient will be the efficiency of a butt and double strap joint, double-
riveted, as shown in fig. 10.
T'S=55,000 lb. per sq. in.
in.=.3125 in.
t=% in. =.375 in.
b =
P=4 in. 4.875 in.
d=% in.=.875 in.
a=.6013 sq. in.
s=44,000 lb. per sq. in.
S=88,000 lb. per sq. in.
c=95,000 lb. per sq. in.
Number of rivets in single shear in a unit length of joint=1.
Number of rivets in double shear in a unit length of joint =2.
A =4.875X.375X55,000=100,547
-
B (4.875-875) .375X55,000 =82,500
C=2X88,000X.6013+1X44,000X.6013=132,286
D=(4.875-2X.875) .375X55,000+1X44,000X.6013=90,910
E (4.875-2X.875) .375X55,000+.875X.3125X95,000 =90,429
=
F=2X.875X.375X95,000+.875X.3125X95,000=88,320
G=2X.875X.375X95,000+1X44,000X.6013=88,800
82,500 (B)
100,547 (A)
=.82 efficiency of joint
Example 4.-Butt and double strap joint, triple-riveted (fig. 11). §).
A =strength of solid plate=PXtXTS
B=strength of plate between rivet holes in the outer row = (P—d) tXTS
C=shearing strength of four rivets in double shear, plus the shearing
strength of one rivet in single shear = NXSXa+nXsXa
D-strength of plate between rivet holes in the second row, plus the shearing
230
Strength of Boilers
strength of one rivet in single shear in the outer row=(P—2d)
tXTS+nXsXa
E=strength of plate between rivet holes in the second row, plus the crush-
ing strength of butt strap in front of rivet in the outer row = (P—2d) t
XTS+dXbXc
F=crushing strength of plate in front of four rivets, plus the crushing
strength of butt strap in front of one rivet =NXdXtXc+nXdXbXc
C=crushing_strength of plate in front of four rivets, plus the shearing
strength of one rivet in single shear = NXdXtXc+nXsXa
Divide B, C, D, E, F or G (whichever is the least) by A, and the quotient
will be the efficiency of a butt and double strap joint, triple-riveted, as
shown in fig. 11.

O
1
C
O
P
TS=55,000 lb. per sq. in.
t=% in.=.375 in.
b = in. =.3125 in.
P=6½ in. =6.5 in.
d=13 in..8125 in.
0
-
··
Fig. 11.-Example of butt and double strap joint, triple riveted.
a=.5185 sq. in.
s=44,000 lb. per sq. in.
S=88,000 lb. per sq. in.
c=95,000 lb. per sq. in.
Number of rivets in single shear in a unit length of joint = 1.
Number of rivets in double shear in a unit length of joint =4.
Strength of Boilers
231

O
#1
•
•
O
A =6.5X.375X55,000 = 134,062
B=(6.5.8125) .375X55,000 =117,304
C=4X88,000X.5185+1X44,000X.5185=205,326
P
O
Fig. 12.-Illustration of butt and double strap joint, quadruple riveted.
D=(6.5-2X.8125) .375X55,000+1X44,000X.5185123,360
E=(6.5-2X.8125) .375X55,000+.8125X.3125X95,000 =124,667
F=4X.8125X.375X95,000+1X.8125X.3125X95,000=139,902
G=4X.8125X.375X95,000+1X44,000X.5185=138,595
117,304 (B)
134,062 (A)
O
.875 efficiency of joint
Example 5.-Butt and double strap joint, quadruple riveted (fig. 12).
A strength of solid plate = PXtXTS
B=strength of plate between rivet holes in the outer row = (P—d)tXTS
C=shearing strength of eight rivets in double shear, plus the shearing
strength of three rivets in single shear = NXSXa+nXsX a
D=strength of plate between rivet holes in the second row, plus the shear-
ing strength of one rivet in single shear in the outer row = = (P—2d}
¿XTS+1XsX.a
232
Strength of Boilers
E=strength of plate between rivet holes in the third row, plus the shearing
strength of two rivets in the second row in single shear and one rivet
in single shear in the outer row = (P—4d)tXTS+nXsXa
F=strength of plate between rivet holes in the second row, plus the crushing
strength of butt strap in front of one rivet in the outer row = = (P—2d)
tXTS+dXbXc
G=strength of plate between rivet holes in the third row, plus the crushing
strength of butt strap in front of two rivets in the second row and one
rivet in the outer row=(P-4d) t×TS+nXdXbXc
H=crushing strength of plate in front of eight rivets, plus the crushing
strength of butt strap in front of three rivets = NXdXtXc+nXdXbXc
1=crushing strength of plate in front of eight rivets, plus the shearing
strength of two rivets in the second row and one rivet in the outer
row, in single shear = NXdXtXc+nXsXa
Divide B, C, D, E, F, G, H or I (whichever is the least), by A, and the
quotient will be the efficiency of a butt and double strap joint quadruple-
riveted, as shown in fig. 12.
TS=55,000 lb. per sq. in.
t=½ in. =.5 in.
b = in. =.4375 in.
P=15 in.
d=15% in.=.9375 in.
a=.6903 sq. in.
s=44,000 lb. per sq. in
S=88,000 lb. per sq. in.
c=95,000 lb. per sq. in.
Number of rivets in single shear in a unit length of joint=3.
'Number of rivets in double shear in a unit length of joint =8.
A.S.M.E. Boiler Code.—Riveting and Calking.
253 Riveting. Rivet holes, except for attaching stays or angle bars to heads, shall be
drilled full size with plates, butt straps and heads bolted in position; or they may be punched
not to exceed 14 in. less than full diameter for plates over in. in thickness, and 1 in. less
than full diameter for plates not exceeding in. in thickness, and then drilled or reamed to
full diameter with plates, butt straps and heads bolted in position.
254 After drilling rivet holes, the plates and butt straps shall be separated and the burrs
removed.
255 Rivets. Rivets shall be of sufficient length to completely fill the rivet holes and form
heads at least equal in strength to the bodies of the rivets.
256 Rivets shall be machine driven wherever possible, with sufficient pressure to fill the
rivet holes, and shall be allowed to cool and shrink under pressure.
CAULKING
257 Caulking. The caulking edges of plates, butt straps and heads shall be beveled. Every
portion of the caulking edges of plates, butt straps and heads shall be planed, milled or chipped
to a depth of not less than 1 in. Caulking shall be done with a round-nosed tool.
Strength of Boilers
233
A=15X.5X55,000=412,500
B=(15-.9375) .5X55,000=386,718
C=8X88,000X.6903+3X44,000X.6903=577,090
=
D=(15-2X.9375) ,5X55,000+1X44,000X.6903=391,310
E (15-4X.9375) .5X55,000+3×44,000X.6903=400,494
F (15-2X.9375) .5X55,000+.9375X.4375X95,000 =399,902
G=(15-4X.9375) .5X55,000+3X.9375X.4375X95,000=426,269
******
H=8X.9375X.5X95,000+3X.9375X.4375X95,000 =473,145
I=8X.9375X.5X95,000+3X44,000X.6903 =447,369
Ⓒ
386,718 (B)
412,500 (A)
= .937=efficiency of joint


O
T
Fig. 13.-Illustration of butt and double strap joint of the saw tooth type.
Ligaments
What is a ligament?
Ans. The section of metal not cut away between two adjacent
tube holes.
234
Strength of Boilers
Where is the section or ligament?
Ans. It lies in a plane passing through the axis of the holes,
that is the line joining the centers of the holes.
When a head is drilled for tubes a good deal of the metal is cut away,
hence the efficiency of the metal between the tube holes or ligament
must be considered.
Name two cases according to the arrangement of the
tubes.

+/½?
Fig. 14.-A.S. M. E. circumferential joint for thick plates of horizontal return
tubular boilers.
Ans. 1, Holes drilled in line parallel to the axis of the shell;
2, Holes drilled in a line diagonal with the axis of the shell.
How are the holes in each row spaced for Case 1?
Ans. The pitch may be equal or unequal.
For equal spacing as shown in fig. 15 how do you de-
termine the efficiency of the ligament?
Ans. By the following formula:
efficiency of ligament
p - d
p
Strength of Boilers
235
in which
Р
d
*******
pitch of tube holes in inches.
diameter of tube holes in inches.
ДОО
54"
5'4"-

Эт
54"
634-
LONGITUDINAL LINE
Fig. 15.-Example of tube spacing, with pitch of holes equal in every row,
illustrating efficiency of ligament.
он
он
54" 64"
он
54"-




p-d
Р
Є
514-332
514
54"-
63/4"
12."
LONGITUDINAL LINE
Fig. 16.-Example of tube spacing with pitch of holes unequal in every second
row, illustrating efficiency of ligament.
это
Example.-If the pitch of the tube hole as in fig. 15 be 514 ins.
diameter of tubes 314 ins. tube holes 332 ins. what is the efficiency of
the ligament?
efficiency of ligament
5.25-3.281
5.25
= .375
For unequal pitch as in fig. 16 how do you determine
efficiency of the ligament?
236
Strength of Boilers
Ans. In this case
54
efficiency of ligament
in which
Р
N
unit length of ligament in inches.
number of tube holes in length p.
= diameter of tube holes in inches.
d
это
54"
Ф
634"
р-
Є
294
Р
nd


54"-
634
оте
LONGITUDINAL LINE
Fig. 17.-Example of tube spacing with pitch of holes varying in every second
and third row, illustrating efficiency of ligament.
p-nd 12-2 X 3.281
p
12
Example. -If the diameter of tube holes be 39 z and the spacing be
as in fig. 16 what is the efficiency of the ligament?
efficiency of ligament =
.453
How do you determine the efficiency of ligament for holes
drilled in a line diagonal with the axis of the shell as in
fig. 18?
Ans. For this arrangement the efficiency of the ligament is
determined by the following formulae using the lowest value
obtained.
Strength of Boilers
237
efficiency of ligament
Where
.95 (p1-d)
P1
p-d
Р
>
P1 diagonal pitch of tube holes in inches.
d diameter of tube holes in inches.
p =
The constant .95 in the formula (a) applies provided
p1 - d be 1.5 or over.
ооо
longitudinal pitch of tube holes or distance between center of
tubes in a longitudinal row of tubes in inches.
ооо
оо
R
-524-
оо
ооо
ооо
| 6.42'
=
ооо
=
Example.-Diagonal pitch of tube holes (as in fig. 18)
diameter of holes 432 ins., longitudinal pitch of holes 1112 ins.
.95 (6.42—4.031)
6.42
11.5-4.031
11.5
.353...
. (a)
LONGITUDINAL LINE-
Fig. 18.-Example of tube spacing with tube holes on diagonal lines, illus-
trating efficiency of ligament.
(b)


6.42 ins.,
(a)
.649....
(b)
Taking the least values determined by formulae a and b, the effi-
ciency of ligament is .353.
NOTE-See A.S.M.E. Code on ligaments P-192 page 44, Sectiqn 1, Power Boilers,
238
Strength of Boilers
:
Reinforcement of Flat Surfaces
How are flat surfaces usually reinforced?
Ans. By stays or braces.
Into what two classes may all reinforcing members be
divided?
Ans. They may be classed as independent and connecting fas-
tenings.
www
What is a stay bolt?
Ans. By definition: A metallic pin or rod, used to hold objects
together and generally having screw threads cut at one end, and
sometimes at both ends to receive a nut.
How are boiler plates tapped so that a threaded bolt or
stay will properly screw into both plates without strip-
ping the threads?
Ans. By the use of a long stay bolt tap which threads both
plates in one operation.
What thread is used for stay bolt taps?
Ans. All sizes of stay bolt taps have 12 threads to the inch.
What diameter of a screwed stay is taken in calculating
its strength?
Ans. The least diameter.
What is a stay rod?
Ans. A through stay especially adapted to short boilers of
large diameter.
Strength of Boilers
239
1
What is the maximum stress allowed on stay bolts?
Ans. 7,500 lbs. per sq. in.
What is the area supported by one stay bolt?
Ans. It is the area enclosed by the two pitches less the area
of one stay bolt hole.
in which
F
Circumferential Joints.-The strength of a riveted circum-
ferential joint of a boiler, the heads of which are not stayed by
tubes or through braces, shall be sufficient, considering all
methods of failure to resist the total longitudinal force acting on
the joint with a factor of safety of 5. The total longitudinal force
is determined by the following formula:
F = 1/4π D² P
P
=
total longitudinal force in lbs.
D
=
Diameter of circular area, acted on by the pressure in producing
the total longitudinal force on the joint in ins.
pressure lbs. per sq. in.
3.1416.
=
π -
When 50 per cent or more of the total force just described is relieved
by the effect of tubes or through stays in consequence of the reduction
of the area acted upon by the pressure and holding power of the tubes
and stays, the strength of the circumferential joints shall be at least
70 per cent that required above.
Areas of Heads to be Stayed
What is necessary where flat heads are used?
Ans. It is necessary to provide stays or braces for that part
unsupported by the tubes.
240
Strength of Boilers
What is the problem usually asked on' examination
papers for engineer's license?
Ans. It is to find the area of the segment of the head (of a
horizontal tubular boiler) to be braced.
The area of a segment of a head to be stayed shall be the
area enclosed by lines drawn 2 in. from the tubes and at a
distance d, from the shell as shown in figs. 19 and 20. The
value of d, used may be the larger of the following values:
$

oooooooooooooooo
5T
2. d
VP
VEEARS TO
R
Fig. 19.-Upper segment of head to be stayed.
1. d=the outer radius of the flange not exceeding 8 times
the thickness of the head.
-
Where
d
unstayed distance from shell, inch.
T
thickness of head in sixteenths of an inch.
P = maximum allowable working pressure lbs. per sq. in.
Strength of Boilers
241
The net area to be stayed in a segment of a head may be
determined by the following formula:

4 (H-d-2)²
1
3
= area to be stayed, sq. in.
where
=
2 (R-d)
(H-d—2
H = distance from tubes to shell, in.
d
distance determined by formula in: Par. P-214 (A.S.M.E.
Power Boilers Code).
R = radius of boiler head, in.
○ ○ ○ ○ Q. 000000
O O O
Q₂OO
*****
area of segment
Fig. 20.-Lower segment of head to be stayed.
Where d 3 ins., area to be stayed in a segment may be determined
by the following formula:
- .608


4 (H-5)²
3
1
2 (R-3)
H-5
sq. ins.
When the portion of the head below the tubes (lower segment), in a
horizontal return tubular boiler is provided with manhole opening, the
flange of which is formed from the solid plate and turned inward to a
depth of not less than three times the thickness of the head, measured
from the outside, the area to be stayed as shown in fig. 20, may be re-
duced by 100 sq. ins. The surface around the manhole shall be supported
by through stays with nuts inside and outside at the front head.
242
Strength of Boilers
Diagonal and Gusset Stays
RULE.-Multiply the area of a direct stay required to support the
surface by the slant or diagonal length of the stay; divide this product
by the length of a line drawn at right angles to surface supported to
center of palm of diagonal stay.
in which
A
a
L
ドー
​ι
=
सीस
A
aL
τ ι
sectional area of diagonal stay sq. in.
sectional area of direct stay sq. in.
length of diagonal stay, as indicated in fig. 21. in.,
length of line drawn at right angles to boiler head or surface
supported to center of palm or diagonal stay as in fig. 21.
1
11
L--
Fig. 21.-Measurements for determining stresses in diagonal stays.
Stay Tubes
When stay tubes are used in multi-tubular boilers to give
support to the tube plates the sectional area of such stay tubes
shall be determined as follows:
total section of stay tubes =
(A-a) P
sq. ins.
TS
C

Strength of Boilers
243
Where
A = area of that portion of the tube plate containing the tubes
sq. in.
α
aggregate area of holes in the tube plate sq. in.
P
= maximum allowable working pressure lbs. per sq. in.
TS tensile strength not to exceed 7,000 lbs. per sq. in.
P-241 Circular Flues. The maximum allowable working
pressure for seamless or welded flues more than 5 in. diameter,
and up to and including 18 in. diameter, shall be determined
by one or the other of the following formulas:
}
(1) Where the thickness of the wall is not greater than
0.023 times the diameter
P = =
(2) Where the thickness of the wall is greater than 0.023
times the diameter
P:
10,000,000/³
D³
P
=
17,300/
D
where P = maximum allowable working pressure, lb per sq in.,
D = outside diameter of flue, in.,
275
t = thickness of wall of flue, in.
(3) The above formulas may be applied to riveted flues
of the size specified provided the sections are not over 3 ft in
length and provided the efficiency of the joint is greater than
PD
20,000/
Example: Given a flue 14 in. in diameter and /16 in. in thickness. The thick-
ness of the wall is less than 0.023 times the diameter; hence formula in (1)
should be used. Substituting the values in this formula:
10,000,000 × 5/16 × 5/16 × 5/16
14 X 14 X 14
110 lb per sq in.
244
Strength of Boilers
P-242 Adamson Type. When plain horizontal flues are
made in sections not less than 18 in. in length and not less
than 5/16 in. in thickness:
(1) They shall be flanged with a radius measured on the
fire side of not less than 3 times the thickness of the plate, and
the flat portion of the flange outside of the radius shall be at least
3 times the diameter of the rivet holes.
(2) The distance from the edge of the rivet holes to the edge
of the flange shall be not less than the diameter of the rivet
hole, and the diameter of the rivets before driving shall be at
least 1/4 in. larger than the thickness of the plate.
(3) The depth of the Adamson ring between the flanges
shall be not less than 3 times the diameter of the rivet holes,
and the ring shall be substantially riveted to the flanges.
The fire edge of the ring shall terminate at or about the point
of tangency to the curve of the flange, and the thickness of the
ring shall be not less than 1/2 in.
The maximum allowable working pressure shall be deter-
mined by the following formula:
(18.75 T - 1.03 L)
maximum allowable working pressure, lb per sq in.,
outside diameter of furnace, in.,
where P
D
⠀ ⠀
PANT
P
P
57.6
D
length of furnace section, in.,
thickness of plate, in sixteenths of an inch.
Example: Given a furnace 44 in. in diameter, 48 in. in length, and ½ in. in
thickness. Substituting values in formula:
57.6
145 [ (18.75 × 8) — (1.03 × 48) ] = 1.309(150
44
-
49.44) = 131 lb per sq in.
Boiler Fixtures and Attachments
245
CHAPTER 18
Boiler Fixtures and
Attachments
Various names such as fixtures, attachments, fittings, trim-
mings, mountings, etc., have been given to the numerous de-
vices fastened to the boiler and which are necessary for its
proper operation.
The term fixtures relates rather to the grate, ash pit, doors,
dampers, funnel, smoke hood, etc., than to fittings such as steam
gauge cocks, etc.
What valves are necessary on a boiler?
Ans. 1, Safety valve; 2, stop valve; check valve; blow off
valve (cock), as shown in fig. 1.
What is the most important valve on a boiler and why?
Ans. The safety valve, because upon its proper operation
depends the safety of those in charge of the boiler. Figs. 2 to 5
show some basic types; fig. 6 names of parts of lever valve.
What is a safety valve?
Ans. An automatic loaded or weighted valve which opens
at a pre-determined pressure and releases steam from the boiler,
thus preventing the steam pressure rising above that for which
the valve is set.
246
Boiler Fixtures and Attachments
What care should a safety valve receive?
Ans. It should be kept clean and should be raised by hand
every morning.
Why should it be raised so often?
Ans. So that it cannot stick in its seat through the accumu-
lation of dirt and scale.
What types of safety valve are in general use?
Ans. The lever safety valve, and the spring safety valve.

STEAM
GAUGE
SIPHON
ANGLE
VALVE
FUSIBLE
PLUG
GLOBE
VALVE
H
INJECTOR
CHECK
VALVE
ANGLE
VALVE
WHISTLE.
CHOH!
ŞAFETY VALVE
STOP VALVE
COCK
GAUGE
COCKS
WATER
GAUGE
GLOBE
VALVE
BLOW OFF
COCK
Fig. 1.-Vertical boiler showing the boiler fittings consisting of control and in-
dicating devices essential for sale operation. A portion of the shell !s cut away
to expose the fusible plug to view.
Boiler Fixtures and Attachments
247
What is the application of each type?
Ans. Lever type generally used in stationary practice;
spring type for marine plants.
How should a safety valve be attached to a boiler?

ADJUSTABLE STOP
LIFT LIMIT
VALVE STEM
CLOSED POSITION
COUNTER BALANCE
་་་
SPRING
םםםםם
•
-HAND WHEEL
OPEN
BOILER
PRESSURE
VALVE CLOSED
TO BOILER
Fig. 2.-Stop or non-return valve. A form of check valve which can be opened
or closed by hand control when the pressure in the boiler is greater than that
in the line, but cannot be opened when the pressure within the boiler is less
than that in the line. The counterbalance spring slightly overbalances the
weight of the valve and tends to hold the valve open, thus preventing move-
ment of the valve with every slight fluctuation of pressure.
248
Boiler Fixtures and Attachments
Ans. It should be attached to a separate outlet, but on
boilers having only one main outlet, it may be attached to a
tee on main steam pipe as close to boiler as possible without
any valve between it and the boiler.
What is a stop valve?
Ans. A non-return valve having a hand wheel and screw
stem which acts only to close the valve. A counter balance
spring tends to keep the valve open. See fig. 2.

F....

B
USALUNKENREIMERGULL
E
LUNKENHEIMER
A*
Figs. 3 and 4.-Swing or hinged type check valve. The design gives a valve
opening area equal to that of the connecting pipes. The valve disc B, is at-
tached by the nut D, to the carrier C, which is pivoted at H. The two side plugs
(fig. 3) serve as bearings for the pivot pin H. Should the movement of the pin
cause the plugs to wear, they can be easily renewed at small expense. To pre-
vent the disc lock nut jarring loose, a hole is drilled through both the lock nut
and threaded end of disc, through which a wire is inserted. To regrind, un-
screw bonnet F, and place some powdered glass or sand, and soap or oil on the
seat; also unscrew plug E, opposite disc, which permits inserting a screw driver
in the slot of the disc.
What is the mistaken idea about a stop valve?
Ans. It is erroneously applied to all hand control valves.
What is the object of a stop or non-return valve?
Ans. The valve is designed to close automatically if any
pressure part fail in a boiler to which it is attached, and to
prevent back flow from the steam header to the point of failure,
thus, isolating automatically a defective boiler from any other
boiler supplying the same header.
Boiler Fixtures and Attachments
249
What is a check valve?
Ans. A form of non-return valve used to control the flow of
water as in pump operation. See figs. 3 to 6.
Name the different types of check valve.
Ans. 1, Disc; 2, ball; 3, swinging; 4, adjustable, etc.
B
Va
POWELL
MODELSTAR
B..
h
A
ง

Fig. 5.-Disc check valve. The check valve disc Vd has integrally cast wing
guides, which snugly engage within the guide C, auxiliary guides being pro-
vided below the disc. To regrind, remove bonnet Ac, lift out guide C, place
a little fine sand or ground glass and water on the disc face, replace same in
the body B, and apply a screw driver to slot in disc stem. Rotate back and
forth until a good bearing is obtained, then carefully wipe off the ground glass
or sand and replace valve guide C, and screw on bonnet.

C
LUNKENHEIMER
Fig. 6.-Ball check valve. This form of check consists of three parts, A, seat
casting; C, ball; B, bonnet. It meets the requirements for users of this type of
check valve, but is not desirable for sizes above 3 inches because of the high
cost and weight of the ball.
250
Boiler Fixtures and Attachments

5.
W....
下
​
M-
J
LUNKENHEIMER
Figs. 7 and 8.—Adjustable lift check valve showing fig. 7, valve without spring
bearing on disc; and fig. 8, detail showing valve with spring bearing on disc.
PACKING NUT
SLAND H
STUFFING-
BOX
OUTLET
BONNET
211
LUNKENHCIMER:

HAND
WHEEL
-VALVE SPINDLE
VALVE
SCREW THREAD
SEAT
PARTITION
INLET
SPHERICAL OR "GLOBE"
SHAPED CASTING
Fig. 9.-Globe valve. A commonly used type of valve which takes its name
from the globe shaped casting forming the body of the valve. It should be noted
that whereas the entire assemblage of parts here shown is ordinarily called a
valve, the term valve, strictly speaking and in accordance with the definition,
means the disc at the end of the valve spindle. This disc is the "lid or cover'
mentioned in the definition.
Boiler Fixtures and Attachments
251
What should be placed between a check valve and boiler,
and why?
Ans. A globe or preferably a gate valve as in fig. 14 to
permit cleaning or repairs to the check valve, as shown in figs.
9 or 12 and 13.
What is a blow off valve?
Ans. A valve of special construction and used to provide
means for: 1, discharging mud, scale and other impurities; 2,
rapid lowering of the boiler water level if too high, etc. One
type is shown in fig. 22.


WATER OR
STEAM
CANNOT ESCAPE
ATER
MOR
STEAM
BATH
RIGHT WAY
WRONG WAY.
Figs. 10 and 11.-Right way and wrong way to connect a globe type
valve in pipe line, showing disastrous result of attempting to repack a wrongly
connected valve. In the illustrations the partition and disc are shown in dotted
lines from which the proper position of the valve is clearly seen.
252
Boiler Fixtures and Attachments
Why is an ordinary valve not suitable?
Ans. Because when the valve is open small pieces of scale
and other foreign matter are hurled against the seat with great
force and grind the surface of the seat and valve away, causing
the valve to leak.
How is this avoided in a blow off valve?


HAND WHEEL-
PACKING NUT
GLAND
STUFFING BOX
SCREW ADJUSTMENT
SEAT
SINGLE DISC
DOUBLE DISC
Figs. 12 and 13.-Single disc and double disc forms of gate valve. Each is
operated by raising or lowering the disc. When closed the two faces of the
disc are tightly pressed (by wedge action) against the seats, thus affecting a
double seal. It should be noted that 'here are two seats for both the single
and double disc types.
Boiler Fixtures and Attachments
253
F
Ans. The valve is so constructed that the valve and seat
when open, are out of the path of the escaping water and im-
purities.
How should a blow off valve be connected to a boiler?

BOILER
1
GATE VALVE
BLOW OFF
VALVE
Fig. 14.-Approved method of connecting a blow off valve. Suppose something
lodged under the blow off valve and you couldn't shut it, then you would have
another chance by closing the gate valve-that is why it is put there.
Ans. A gate valve should be placed between the blow off
valve and boiler, as shown in fig. 14.
Why?
Ans. To insure a tight outlet and to provide additional
means of shutting off the connection in case anything happen
to the blow off valve.
254
Boiler Fixtures and Attachments

HANDLE
HEXAGON
HEAD
SEAT
PIPE
THREAD
SQUARE LOCK
SIDE PRESSURE
ON SEAT AT
LOWER END
SQUARE 'SHANK
SIDE PRESSURE
ON SEAT AT
UPPER END
WASHER
RETAINING NUT
Fig. 15.-Straight way cock showing ends tapped for connection in the run
of a pipe line, and detachable handle.
WRONG WAY
TURNING G
FORCE
SET SCREW
NO SIDE
PRESSURE
ON SEAT
RIGHT WAY
T
HEXAGON
HEAD
VALVE
PIPE
THREAD


M
ARF
S
APPLIED FORCE
APPLIED FORGE
Figs. 16 and 17.-Wrong and right way to open a ground cock. Grasping the
handle as in fig. 16, and simply pulling it toward you, brings considerable pres-
sure against the seat and tends to warp or distort seat causing leakage. The
handle should be turned as in fig. 17, pushing with the thumb T, and pulling with
the other fingers L,A,R,F, producing forces M and S. The force M, prevents
side pressure due to S, coming on the valve seat giving a resultant turning force
G, around the valve axis.
Boiler Fixtures and Attachments
255

POWELL
int
14
DIMMUNE RU
POWELL
POWELL
#
2
POWELL
5
www.
·
POWELL
חיוור
AU
POWELL
UIDIN
3
6

Figs. 18 to 23.-Plain straight way steam cocks. 1, Flat head; 2, square head; 3, T head; 4, flat head,
male and female; 5, flat head, both ends male; 6, flat head, both ends female.




256
Boiler Fixtures and Attachments

POWELL
Fig. 24.-Straight way packed valve steam cock for
working pressures up to 200 lbs. In construction,
the valve is passed up through the bottom of this stop
cock, the reverse of the usual way, and is held to its
bearing by a spring in the bottom cap. Holes are
drilled in bottom of key, allowing fluid to act as a
cushion. The stem is provided with the usual packing
nut. Care must be observed not to get the packing
too tight-it may throw the valve off its seat. These
cocks are made with screw bottom nut up to 1½ in.,
1/4 in. and larger with bolted flange nuts, as indicated
in dotted lines.


STOPS
CHECK
PIN
CHECK
PIN
06
OPEN
CLOSED
Figs. 25 and 26.—Straight way cock with stops and check pin in open and
closed positions. This control device is especially desirable on three way, and
waste cocks.
Boiler Fixtures and Attachments
257

BRANCH
L
FLOW
TWO PORTS
HOD TOH
ON
BRANCH
SHUT
OFF
ON
-MAIN LINE
ФОР
OFF
F
FLOW
Figs. 27 to 29.-Two port three way cock showing
flow control. Fig. 27, on in branch L; fig. 28, on in
branch F; fig. 29, water shut off from both branches.


258
Boiler Fixtures and Attachments
-ON
-ON
ON-****
C
LOLOLOS
L
Figs. 30 to 33. Three port three way cock showing flow control.
Fig. 30 on in branch Land run R; fig. 31, on in branch L, off in
run R; fig. 32, on in main line FR and off in branch L; fig. 33
supply run F shut off from both branch L, and distribution run R.

FLOW
MAIN
LINE
MAIN
LINE
OFF
BOD
-ON-
FLOW

Boiler Fixtures and Attachments
259


BRANCH
MAIN
L
BRANCH
TWO PORT FOUR WAY COCK
L
OFF
OFF
MAIN
OC
BRANCH
OFF
Figs. 34 to 37.-Four way two port cock control diagrams.
T
«««
MAIN
MAIN
R
OFF
BRANCH
R
OFF
THREE PORT FOUR WAY COCK
F
MAIN
L
OFF
Figs. 38 to 41.-Four way three port cock control diagrams.
MAIN
20
R
BRANCH
R
L
L
E
IF
OFF
OFF




260
Boiler Fixtures and Attachments
How should a blow off connection be made on a hori-
zontal return tubular boiler?
Ans. The boiler shell is tapped at the rear end for the blow
off pipe. The latter should preferably be run straight down to
below the floor level of the combustion chamber and then out,
the pipes in the combustion chamber being protected from the
heat by some insulating material as tile, brick, etc.
What is a cock?
BRANCH
NCH
MAIN...
MAIN-
FOUR PORT FOUR WAY COCK



MAIN
OFF
Figs. 42 to 44.-Four way four port cock control diagrams.
Ans. A device for regulating the flow of fluids through a
pipe; a typical straight way cock is shown in fig. 15.
How is it usually constructed?
Ans. It usually consists of a tapered conical plug having a
hole or port in it, and working in a shell of iron or brass bored
out to receive the plug and provided with passages to connect
into pipes at either end.
How is a cock operated?
Ans. Rotation of the plug (90°) controls the passage of
Boiler Fixtures and Attachments
261

OFF
DRAIN PORT-
and drain outlet.
DRAIN
Figs. 45 and 46.-Waste or drain cock showing operation; fig. 45, on position, water flowing through run;
fig. 46, off position,
of run draining through drain port
end
distribution
DRAIN OUTLET
fluids by bringing the opening
in the plug opposite those in
the shell or away from them.
Fig. 16 shows how not to turn
a cock. Figs. 27 to 55 show how
various cocks work.
How many cocks are ordi-
narily attached to a boiler?
***
Ans. One or more blow off
cocks and three gauge cocks.
What is a gauge cock?
Ans. A device for determin-
ing the water level in the boiler.
A few varieties are shown in
figs. 47 to 62.

How is the water level de-
termined by means of
gauge cocks?
Ans. Each cock is open
slightly and the presence of
water or steam escaping from
the cock tested by its appear-
ance, sound, and feel to the
hand.
262
Boiler Fixtures and Attachments
The right and wrong methods are shown in figs. 51 and 52.
Why is the cock only slightly opened in testing?
Ans. Because a full opening tends to raise the water level,
thus giving a false level.
What are the two principal types of gauge cock classed
with respect to the means employed for closing?
Ans. Compression and pressure.

POWELL
Fig. 47.-Spring cock; long shank push button or "Mississippi" pattern.

粥
​POWELL
Fig. 48.-Compression cock; short shank, weighted lever or "ball" pattern.
Figs. 49 and 50.-Combined spring and diaphragm compression cock.
Boiler Fixtures and Attachments
263
What is a Mississippi cock?
Ans. One in which steam pressure keeps the cock closed and
a push button is provided to open the cock.
What other name is given to gauge cocks?
Ans.
"Pet" cocks.


SLIGHTLY
OPEN
STEAM
TRUE
LEVEL
FALSE
LEVEL
WIDE
OPEN
+.
WATER
Figs. 51 and 52.-Right and wrong way of testing water with gauge cocks.
When the cock is only slightly opened, as in fig. 51, the water level is not
materially raised by the outrushing steam, but if opened wide, as in fig. 52,
the reduction of pressure inside and consequent violent ebulition to restore
equilibrium causes a considerable disturbance of the water level near the cock,
resulting in a false level as shown. This precaution should be remem-
bered, especially when using the lower cock, because if opened wide, the
water is lifted surprisingly high, hence, unless the lowest cock be at a liberal
height above the crown sheet, it may when opened wide indicate water though
the true level may be dangerously low.
What is a water gauge?
Ans. A device used to indicate the height of water within a
boiler. Typical construction is shown in figs.58 to 60.
264
Boiler Fixtures and Attachments
How is it constructed?
Ans. It consists of a strong glass tube, long enough to cover
the safe range of water level, and having the ends connected to
the boiler interior by fittings. Since both ends of the tube are
in communication with the boiler, the water level in the tube will
be approximately the same as that in the boiler.

NE
K
»…………
F.
H.

LUNKENHEIMER
LUNKEN-E'
*[20FEREN
Figs. 53 to 55.-Self grinding gauge cocks. In operation (fig. 53) when the
lever is moved to open position, the projection X, presses against the oose piece
A, which forces back the stem E, and unseats the disc allowing steam or water
to pass out of the nozzle. The guide next the disc is provided with spiral grooves,
so that the water or steam in passing through these spirals will impart a rotary
motion to the stem E. When the pressure on the loose piece A, is released, the
boiler pressure forces the valve to its seat, while the stem is rotating, thus grind-
ing in the seat bearing a little every time the cock is opened. The piece A, being
independent precludes the possibility of wedging between stem and body.
Why approximately?
Ans. It registers a false level lower than the level in the
boiler because of the difference in temperature of the water in
the tube and in the boiler, as shown on page 324.
What is a water column?
Ans. A boiler fixture consisting of a cylindrical piece to
Boiler Fixtures and Attachments
265
which are attached the water gauge and gauge cocks, thus
combining the two into one unit. The top and bottom have
outlets which connect it with the boiler below and above the
water level, as shown in fig. 62.
What fittings should be used for these connections?
Ans. Tees, with plugs, not elbows.
CRANK
HANDLE
Why?
Ans. So that by removing the plugs, the connecting pipes
may be cleaned of any foreign matter.

MALDI-
F
Wille
WORN THREAD AND
DISTURBED ALIGNMENT
UNBALANCED
FORCE
HAND WHEEL
D
BALANCED
FORCES
NO LATERAL STRESS
ON STEM OR THREADS
Baada
igs. 56 and 57.-Why the author objects to crank handles on cocks or any
other screw fittings. The illustrations require no explanation; however, it might
be mentioned that cocks, like nuts, are usually screwed without judgment,
that is closed with entirely too much force, hence a considerable turning force
is sometimes required to open them. When this force is applied to a crank as in
fig. 56, since it is unbalanced, the lateral thrust must be resisted by the threads
at diagonally opposite points. Moreover, when the threads become worn from
this abuse, as soon as the crank begins to turn, the alignment is destroyed and the
valve tends to dig into the seat at L, and to leave it at F, here shown exagger-
ated for clearness. The unequal grinding effect tends to cause a leak at F.
266
Boiler Fixtures and Attachments
What is a steam gauge?
Ans. A device for indicating "gauge" pressure as distin-
guished from absolute pressure.
How does a steam gauge work?
Ans. A steam gauge (according to type) works on one of
two principles: 1, the expansion of a corrugated diaphragm



III
=SOИKENHEIWEB
TONKENREIWER
NUKEKHEIWEK:
BUT I DO LAKOS
Figs. 58 to 60.-Four, three and two rod plain cylindrical water gauges. The
plug in the top fitting permits replacing the glass tube.
when pressure is applied, and 2, the tendency of a curved tube
to assume a straight position when under pressure.
The two types are shown in figs. 63 and 64 and operation of the
curved tube gauge in fig. 65.
What are the indications that a steam gauge is working
properly?
Boiler Fixtures and Attachments
267
PŠTI
P
„JEWELLER
*** MRSA aut
ROWELL
SURM
me
BOILER
CONNECTION
STEAM GAUGE
WATER GAUGE
-GAUGE, COCKS
WATER GAUGE
DRAIN
BOILER
CONNECTION
Fig. 61. Automatic offset cylindrical water gauge. The automatic cut off balls in shank close in case the
glass break.
Fig. 62.-Water column without fixtures showing the various openings and what they are for.


268
Boiler Fixtures and Attachments


0
VG
}}}}}}|
с
Figs. 63 and 64.-Diaphragm and bent tube as used in the two classes of steam
gauge.
FIXEO END'
HAIR
SPRING
wwww
HAND
PIVOT
E
F
PINION
FREE
END
RACK
m
A B
A
B

Fig. 65.—Multiplying mechanism of a bent tube steam gauge, showing zero
position in full lines, and one position under pressure in dotted lines. The free
end, A, of the tube is connected by a link to the rack arm at E, the latter being
pivoted at F, as shown. Evidently when the free end of the tube moves a short
distance, as from A, to B, the motion of the pointer or indicating hand will
Boiler Fixtures and Attachments
269
Ans. The index or pointer moves easily with every change
of pressure in the boiler and if the steam drop to atmospheric,
the hand should go back to zero.
How is the accuracy of a gauge tested?
Ans. By comparing it with a test gauge.
What is a goose neck?
Ans. A short length of pipe having one complete turn and
to which the steam gauge is attached.
What's the idea of curving the goose neck?
Ans. It traps condensate, gradually fills, and the cool water
prevents live steam touching the corrugated diaphragm tube.
However, it should be filled with water when the gauge is in-
stalled.
How are steam gauges quickly ruined by greenhorns in
charge of contractors' outfits, saw mill rigs and other
nondescript outfits?
Ans. By disregarding the precaution of including a goose
neck between the gauge and its connection to the boiler.
Did you ever notice a gauge connected to a boiler with just a straight
nipple? Some greenhorn did the pipe fitting. Proper methods are shown
in figs. 66 to 68.
How should a goose neck be connected, and why?
move a much greater distance as from C, to D. In construction, by making
EF, of suitable length, any degree of sensitiveness may be obtained, thus
adapting the gauge for a low or high range of pressure. The hair spring which
is connected with the pointer shaft, offers a slight resistance which takes up the
lost motion in the mechanism and renders it "taut" at all times.
270
Boiler Fixtures and Attachments
Ans. It should first be filled with water to protect the gauge
mechanism from the hot live steam.
What is an injector?
Ans. An instrument for forcing water into a boiler against
the boiler pressure by means of a steam jet.
Injectors are treated at length in Chapter 29.



120
100
140
160
River in t
180
260
220
200
240
09
200
160
140
100
18
LOCOMOTIVE.
TIVE.
260
300
90 110
50
1501507
WHI
210 061
250 230
Figs. 66 to 68.–Various forms of connection for steam gauge. The pocket
formed by the connection becomes filled with water of condensation which
protects the spring from the heat of the steam.
What is a fusible plug?
Ans. A safety device which acts in case of dangerously low
water. It consists of an alloy of tin, lead and bismuth and a
covering of brass or cast iron, as shown in fig. 69.
Some plugs have a casing of bronze with a core of practically pure
tin, having a melting temperature of 400 to 500° Fahr.
Boiler Fixtures and Attachments
271
What should be noted about fusible plugs as a safety
device?
Ans. They are greatly overrated.
Why?
Ans. They are unreliable, sometimes blowing out when there
is no apparent cause and sometimes remaining intact when the
plates become over heated.
What precaution should be taken with fusible plugs?
Ans. They should be renewed at least once every six
months of service.
What is the pressure limitation for fusible plugs?
Ans. They are seldom used for pressures above 250 lbs.
per sq. in.
Where are fusible plugs placed?
Ans. In the parts exposed to great heat. In the crown sheet
of a locomotive boiler, in one of the tubes of a vertical boiler.
Define the term furnace?
Ans. That part of the boiler designed for burning the fuel.
Describe the grate assembly for a horizontal return
tubular boiler.
Ans. It consists of the 1, grate; 2, front support or dead
plate; 3, rear support or bridge wall; 4, main combustion cham-
ber; 5, supplementary combustion chamber.
How is the grate constructed?
Ans. It is of cast iron made up in sections each containing
numerous so called grate bars.

272
Boiler Fixtures and Attachments
GIGA
UNKENHEIMER
10/889
4.S.M.E
STD.
MS. FIRE SIDE
Fig. 70-End of fire
box boiler show-
ing fusible plug in
crown sheet in the
act of blowing.
Fig. 69.-Fusible plug (outside type). Each
plug is stamped "A.S.M.E. Std." on the
bronze casing to signify conformance with
A.S.M.E. code specifications. A.P.I. Field
Boiler Code requirements are the same as
A.S.M.E. Code. A heat number stamped
on the fusible core of each plug is the mark
of approval of the Bureau of Marine In-
spection and Navigation, Department of
Commerce, and signifies that samples of
each "heat" have been submitted to the
Department for test and have been ap-
proved. The A.S.M.E. Boiler Code rules do
not prescribe a restrictive upper limit for
steam pressure, but deem it unnecessary to
use fusible plugs when boilers are operated
at working pressures in excess of 250 lb.
per sq. in. Regulations of the Bureau of
Marine Inspection and Navigation prohibit
the use of fusible plugs when temperatures
exceed 425° Fahr. Fusible plugs are made
of bronze and are filled with
pure Banca tin. The long pipe
threads fit not only standard pipe-threaded openings, but also
openings that have been stretched oversize.
FUSIBLE PLUG
REFERE
20
D00000
0 0 0 0
00000
Boiler Fixtures and Attachments
273
What duties are performed by the grate?
Ans. It serves the purpose of holding the fuel while it burns
and of admitting sufficient air so that it can burn.
Why are there numerous types of grate bars?
Ans. Because of the great variety of fuels each requiring
different conditions for best combustion.
How much air space is provided?
Ans.
From 30 to 50% of the grate area.
Why are grate bars tapered to give a wider opening be-
tween the bars at the lower end?
Ans. For free flow of air and cooling.
How wide are the air spaces?
Ans. They vary from 3 to 1 inch wide.
How long should grate bars be made?
Ans. Not longer than three feet.
What precaution should be taken in installing grate
bars?
Ans. Ample space should be provided for expansion.
Why do some grate bars have a shallow groove running
along the top?
Ans. To fill with ashes which tends to prevent clinker.
Where are shaking and dumping grates extensively used?
Ans. On house heating boilers because of the very low grade
of intelligence exercised in firing, the fire is frequently extin-
guished, making it necessary to dump the fuel.
274
Boiler Fixtures and Attachments

+37
K
M
N--
LUNKENHEIMER
--B
KARLANEAZKAZZZZZZKRIVALLEman
-A
H
E---
LUNKENHEIMER
-G
L H
X---
Fig. 71.-Single tone whistle. The supply of steam is regulated by the valve D,
which opens against a weak spring L, and the steam pressure, the opening force
being applied to the stem F, through lever E, by means of a chain or wire at-
tached to the lever at its upper end. The sound is produced by the rush of steam
in a thin cylindrical sheet through opening M, directly against the edge of the
whistle bell A, in which the vibrations necessary to produce the sound are
produced. The bell is held in place by the threaded rod B, and jamb nut M.
The lever pivot J, is secured by nut, H. By removing cap K, the valve may be
removed for examination or repair.
Fig. 72.-Typical balanced whistle valve. In operation, steam pressure on the
disc C, normally holds it to its seat. A slight pull on lever X, suffices to open the
small auxiliary valve A. This admits steam through the opening in the center
Boiler Fixtures and Attachments
275
Mention some smoke prevention arrangements used.
Ans. 1, Large combustion chamber; 2, supplementary com-
bustion chamber; 3, baffle plates; 4, brick checker work; 5, sup-
plementary air supply; 6, Dutch oven; 7, down draught
furnace, etc.
HIGH
MAJOR
SIREN OR
MOCKING
BIRD
WHISTLE
SINGLE BELL WHISTLES
J



CHIME WHISTLES
f
MEDIUM
MINOR
portamente
Ill
AUGMENTE.D
FIFTH
p
Fig. 73 to 80.-Musical effect of various whistles.
ff p
O
LOW




B
SEVENTH

What is the advantage of pre-heating the air?
Ans. The affinity of heated air for carbon being much
greater than that of cold air, it raises the intensity of com-
bustion.
What limits the depth of the ash pit?
Fig. 72.-Text continued.
of the stem of valve C, to expansion chamber where it acts upon the piston, the
area of which, being equal to that of valve C, practically balances it, and with
only a slight additional pressure, the valve opens wide. When lever is released,
the spring E, closes auxiliary valve A, and the main valve C, closes easily with-
out jar, as the steam entrapped in the balancing expansion chamber tends to
cushion and retard its movement.
276
Boiler Fixtures and Attachments
12.
Ans. The height of the grate above the floor at which firing
can be conveniently done-not more than 20 ins.
How is the best way to induce a fireman to regulate the
draught by the damper in the stack and not by the ash
pit doors?
Ans. Remove the ash pit doors.
+
Boiler Accessories
277
CHAPTER 19
Boiler Accessories
These are numerous accessories to be provided for boiler
operation. Among these may be mentioned: 1, feed pump;
2, feed water heater; 3, economizer; 4, feed water regulator;
5, separator; 6, steam traps; 7, steam loop, etc.

ARTURTINANTAIH
Fig. 1.-A very small duplex pump. Size: 2 ins. diameter steam cylinders;
1% in. water cylinders; 2% in. stroke. Its capacity is .004 gals. per revolution;
rev. per minute 80; gals. per minute 3.5. Steam pipe % in.; exhaust pipe ½ in.
inlet pipe 1 in.; discharge 34 in. Floor space occupied 1 ft. 9 ins. x 7 ins. wide.
This pump supplied feed water to the 2½ x 3 Roberts boiler of the author's
steamer Stornoway 1, the engine being a 3,5 and 8 by 6 Herreschoff triple
expansion condensing.
What types of feed pumps are used for pumping water
into the boiler?
Ans. Reciprocating and centrifugal.
Name two well know types of reciprocating pumps.
Ans. Simplex and duplex.
278
Boiler Accesoriess
What can be said of a simplex pump as to reliability as
compared with a duplex pump?
Ans. Not much. It is a tempermental pump unless in A-1
condition and sometimes acts as bad as a gas engine.
What is a duplex pump?
Ans. A combination of two pumps arranged side by side
and so connected that movement of each operates the steam
valve of the other.
Which is the larger cylinder in a boiler feed pump and
why?
Ans. The steam cylinder to overcome the hydraulic pres-
sure and the considerabie friction of the pump.
What can be said of a duplex pump?
Ans. It is the most reliable type and at the same time most
wasteful of steam.
Name a desirable characteristic of the duplex pump.
Ans. There is no dead point at any point of the stroke.
Feed Water Heaters
What is a feed water heater?
Ans. An apparatus for raising the temperature of boiler
feed water with exhaust steam.
What are the reasons for heating the feed water?
Ans. It results in a saving in fuel and also frees hard water
of much of its scale forming salts. Moreover the water entering.
Boiler Accessories
279
3
the boiler at high temperature brings less strain on the shell
than in the case of high temperature differences.
Name two types of heater in general use.
Ans. 1, Open; and 2, closed.
FEED INLET
f
Describe an open heater.
Ans. This type consists essentially of an open chamber in
which the exhaust steam and water to be heated are brought
CLOSED
OPEN
OUTLET
SUMP:
DISTRIBUTION
TRAY
STEAM
INLET
FEED OUTLET
STEAM
OUTLET
STEAM
INLET


FLOW
BAFFLE
FEED INLET
FEED OUTLET
'Figs. 2 and 3.-Elementary diagrams showing essential features of open and
closed feed water heaters.
into intimate contact by spraying the water through the steam,
both the water and condensate going to the boiler.
What are the features of the open heater?
Ans. It is more efficient than the closed heater and by means
of a series of pans, scale forming substances can be precipitated
before the water enters the boiler.
280
Boiler Accessories
Where should the feed water enter a closed heater?
Ans. At the top of the heater or where the exhaust steam
is leaving the heater.
Why?
Ans. Because if exhaust steam and the feed water entered
at the same place, the cold water coming in direct contact
with the highest temperature of the steam would cause the
tubes to become brittle or crystallized at that point.
What is a closed heater?
Ans. A type of heater in which the steam and feed water
are separated by a metal surface.
Where is a feed water heater placed?
Ans. Between the engine exhaust and the boiler.
To what temperature will a heater heat the feed water?
Ans. To about 10° to 15° less than the temperature of the
exhaust steam.
What is the saving due to heating the feed water?
Ans. About 1% per each 112° rise in temperature of the
feed water.
What other method is employed for heating feed water
besides a feed water heater?
Ans. Heating by use of an economizer.
What is the distinction between a feed water heater and
an economizer?
Ans. Both in function, are feed water heaters, the distinction
being that the feed-water heater receives heat from exhaust
Boiler Accessories
281
steam whereas the economizer receives its heat from the hot
gases of combustion.
BOILER
What is an economizer?
Ans. A second stage feed water heater placed between the
boiler and stack, so as to absorb a portion of the heat not
absorbed by the boiler.

FEED INLET
HOT GASES
Where is an economizer placed?
Ans.
Between the boiler and stack.
STACK
FEED OUTLET
-
Fig. 4. The make up of an economizer. By definition, an economizer is a
type of feed water heater which receives its heat from the hot gases of combus-
tion instead of from the exhaust steam. As usually connected, it is a secondary
heater; that is, it receives its feed water from the exhaust steam heater or
primary heater.
What is the usual temperature of the hot gases escaping
up the chimney?
Ans. Approximately from 500° to 700° Fahr.
282
Boiler Accessories
Since the temperature of steam, say at 100 lbs. pressure, is only
338° Fahr., it is evident that a large amount of heat is going to waste,
some of which could be profitably recovered by means of an economizer.
What is the usual construction of an economizer?
Ans. The usual construction consists of steel tubes (coils
or in parallel) through which the water flows, being sur-
rounded by a casing to guide the hot gases over the heat-
ing surface.
How does an economizer.operate?
Ans. Feed water is forced through the tubes while the gases
circulate around them.
What provision should be made to cope with the condi-
tion under which economizers work?
Ans. Since soot is a very efficient heat insulator, any deposit
on the tubes will considerably reduce the efficiency of the
heating surface, hence some device should be provided for con-
tinuously or periodically removing the soot from the heating
surface of the tubes.
Describe typical economizer construction.
Ans. It consists of a series of tubes made up in sections,
connected at the ends, and placed in a brick chamber through
which the gases pass from the boiler to the chimney or fan.
Feed Water Regulators
What is a feed water regulator?
Ans. An automatic device which controls the amount of feed
Boiler Accessories
283
water admitted to the boiler so as to maintain a constant
water level.
JODOLEKANI
Describe a simple form of regulator.
Ans. It consists of a hollow metal buoyancy float placed in

TO BOILER
BUOYANCY FLOAT
********I
G@MEELEL652EFALET
PERKAKAOMI
NEEDLE BYPASS VALVE
TANK
Fig. 5.-Elementary buoyancy float feed water regulator.
FEED PUMP
the water column which moves up and down with changes in
the water level and operates the feed supply valve, or by pass,
thus regulating the quantity of feed water admitted.
284
Boiler Accessories
What is a steam trap?
Ans. An automatic device which allows the passage of water
but prevents the passage of steam.
VALVE
SEAT OUTLET
REVERSIBLE)
What is a trap used for?
Ans. To drain pipes of condensate.
BODY
BLOW
OFF
(XX)
Steam Traps
1101
BONNET
MAIN VALVE
PILOT VALVE
VALVE CAGE

INLET
BUCKET
WINGED
GUIDE
(BRASS)
DISCHARGE
TUBE
リリカ
​Maligining
ANA.
Figs. 6 and 7.-Bucket pilot valve steam trap. Fig. 6 before discharge;
fig. 7 during discharge. In operation, condensation enters the trap at inlet
against baffle plate, and overflows into the bucket, which when full, drops and
opens the pilot valve. This relieves the pressure under the main valve and the
pressure on top of this valve, under the seat, then forces it to bottom of
cage.
The condensation is then discharged from bucket down to low water line which
keeps end of discharge tube always water sealed. The bucket then rises and
valves close.
In construction how is the device shaped so as to intro-
duce centrifugal force?
Ans. By introducing a partition or equivalent means to sud-
denly change the direction of the fast flowing steam usually
through 180°.
Boiler Accessories
285
What may be said of steam traps?
Ans. According to Crane, “A trap is a trap and it is unfortu-
nate that it is impossible to get along without them.'
""
According to the author "They are frequently too much annoyance
and breeding devices for profanity”—This goes also for injectors when
not properly installed.
Are there many types of traps on the market?
Ans. There is an undue multiplicity of traps on the market
(each one better than the others according to the maker).
Name four types of traps extensively used.
Ans. 1. Non-return; 2, return; 3, intermittent; 4, continous.
For additional information on Steam Traps, see Chapter 30.
What is a steam loop?
Ans. An ingenious "thermal pump" consisting of an arrange-
ment of piping wherein condensate is returned to the boiler.
See page 289.
Why call it a thermal pump?
Ans. Because its basic principle of operation is the expenditure
of heat to cause condensation and pressure difference.
Separators
What is a separator?
Ans. A device designed to remove as much moisture as pos-
sible from steam after it leaves the boiler.
Where is it placed and why?
286
Boiler Accessories
Ans. Close to the engine so as to avoid any further conden-
sation between separator and engine.
What is the outstanding basic force which causes the
separation of moisture?
Ans. Centrifugal force.
Any other force?
Ans. Sometimes gravity as a secondary force.

COLLECTOR
SEPARATOR
DRAIN
WATER
LEVEL
BAFFLE PLATE
COLLECTOR
CYBUGUN
DRYER
EXIT
ERCH
Fig. 8.-Detail showing separator, collector, and dryer on Graham through
tube vertical marine boiler. This design makes possible working with an ab-
normally high water level, thus increasing the efficiency of the upper heating
surface.
How does the centrifugal force act?
Ans. Change in direction of the steam flowing at 6,000 to
8,000 ft. per minute creates very great centrifugal force which
acting on the heavy globules of condensate hurls them out of
the path of the steam.
What is usually provided on a separator and why?
Boiler Accessories
287

FROM BOILER
WET
STEAM
HIGH VELOCITY
RESERVOIR AND-
VELOCITY REDUCING
CHAMBER
DRAIN
**:
R
TO ENGINE
1-33=
CONDENSATE
Fig. 9.-Elementary steam separator, illustrating principles of operation. Steam
from the boiler is led into chamber of larger section than the pipe, and out
again after: 1, having its direction suddenly changed (usually through
180°), and 2, having its velocity reduced while passing through the cham-
ber. Change in direction of the steam flowing at 6,000 to 8,000 feet
per minute creates considerable centrifugal force which acting on
the heavy globules, hurls them out of the path of the steam. The
velocity of the steam in changing its direction is reduced because of the large
size of the chamber which diminishes the disturbance due to the steam passing
through the chamber, thus increasing the efficiency of the device.
DS
-DRIP PIPES:
ZIMI
DRY STEAM
LOW VELOCITY
CONDENSATE
GAUGE

A
E-E
WATER LINE
WATER CHAMBER
Figs. 10 and 11.-Dry pipe or internal separator. In operation, the steam after
rising, enters the separator through two narrow slots Ċ (fig. 11), and in passing
down through the thin passages c, is brought in contact with the perforated
plates or lining D, through which moisture is separated to water chamber.
Steam from passages c, then enters the main pipe A, from which it is taken
from the boiler. Water in water chamber is conducted to the water in the boiler
by drip pipes E, which are provided with check valves as shown.
288
Boiler Accesoriess
Ans. A reservoir to catch the condensate and having a glass
gauge and drain cocks, the collected condensate is usually
automatically removed by a trap.
Collectors
What is a collector or so called dry pipe?
Ans. A pipe placed inside a boiler at a high point and having
small perforations extending its length so as to take off steam
at a multiplicity of points and thus avoid turbulence by taking
off steam at only one point.

Fig. 12.-Typical separator; sectional view showing construction. The baffle plate
which serves to change the direction of the steam flow is not set at right angles
to the entering steam current, but is set at an angle so that when the steam is
impinged against it, the particles of water rebound at an opposite angle. This
sets up a rotating motion in the steam, bringing the latter in contact with the
inside walls of the separator. These walls are heavily corrugated, as is also the
surface of the baffle plate, and all corrugations are designed so as to carry the
drainage out of and away from the course of the steam. Any moisture not
caught by the upper baffle plate and by the inner walls, is subject to further
separation process by means of additional baffle plates located in the well or
receiver portion of the separator, one of these plates being shown in the illus-
tration. The separator is adapted for steam flow in either direction.
Boiler Accessories
289
What is the matter with calling a collector a separator?
Ans. It's distinctly a misnomer, because the function of a
collector is to collect steam from a multiplicity of points in
small amounts from each point, thus bringing into action dis-
engagement over practically the whole disengaging surface.
Steam Loop
What are the four essential parts of a steam loop?
Ans. 1, Riser; 2, goose neck; 3, condenser; 4, drop leg.
2 GOOSE NECK
1
RISER
12
Dis
WET STEAM
+7
SO CALLED
HORIZONTAL PIPE
HORIZONTAL LINE
3 CONDENSER
INCLINED

یام
4-
DROP LEG
CONDENSATE
WINIAMHELMEMBERMAUNGARINNAR ESSE
CHECK VALVE
Fig. 13.-Essential parts of a steam loop: 1, riser; 2, goose neck, or non return
device; 3, condenser, commonly and erroneously called the horizontal pipe;
4, drop leg, or balancing pipe. A check valve is placed at the end of the drop.
leg to prevent surging or fluctuating of the water level, thus rendering the oper-
ation stable. There are two conditions necessary for proper operation of a loop:
1, sufficient length of drop leg to balance the pressure reduction due to weight
and friction of the mixture in the riser; 2, sufficient cooling surface of condenser
to condense at a rate which will give the proper flow in the riser.
290
Boiler Accessories
1
What determines the capacity and strength of the
system?
Ans. The proportions of the four parts.
How does a steam loop work?
Ans. The riser does not contain a solid body of water, but a
mixture of water and steam.
The steam part of this mixture is readily condensed by means
of the condenser at the top, usually and erroneously called the
horizontal pipe. This condensation reduces the pressure in the
system which causes an upward flow of the mixture in the riser,
that is, the riser is constantly supplying steam, conveying large
quantities of water in the form of a fine spray to take the
place of the steam condensed in the condenser.
As soon as the water mixed with the steam passes the goose neck, it
cannot return to the riser; hence the contents of the pipes constantly
work from the riser toward the boiler, the condenser being slightly
inclined toward the drop leg so as to readily drain the condensate
into the drop leg.
The condensate will accumulate in the drop leg to a height such that
its weight will balance the weight of the mixture in the riser.
+
Boiler Operation
291
BOILER
Boiler Operation
A boiler is a dangerous device in the hands of a greenhorn
hence a thorough knowledge of its behavior under varying
conditions is necessary for safety.
CLOSE ELBOW
EASY
BEND
A
CHAPTER 20

LONG LENGTH OF PIPE
GOOD
B
EXHAUST、
BAD
Fig. 1.—Right and wrong methods of piping boiler and engine of steam vessel.
A, shows short steam pipe with long sweep fittings, or made in one piece bent
to easy curve. This arrangement gives the minimum resistance to steam flow and
minimum radiation loss. B, shows a very objectionable method, and represents
the actual piping which the author once saw in a U. S. Navy launch. Note the
extra length of pipe due to placing the h.p. cyl. aft, also the close elbows.
This arrangement will give considerably more pressure drop between boiler
and engine and radiation loss than the arrangement at A. The author cannot
think of any reason that would justify turning the engine around backward, as
in arrangement B, and considers the whole arrangement very objectionable.
292
Boiler Operation
¡
The term operation broadly includes:
1. Installation.
2. Getting up steam.
3. Firing.
4. Repair.

GOOD
+
!!!
Ser
00
Figs. 2 and 3.-Good and bad practice in power house construction. The only
way to protect engine bearings from a constant bath of grinding matter from the
boiler room is to build a solid wall as in fig. 2. The result of providing a door
between boiler and engine room is seen in fig. 3. This door is always kept open,
especially when the fireman is removing the ashes and the only way to keep
such doors closed is to make them of solid brick, as in fig. 2.
BAD
BLAST OF ASHES, COAL DUST,
GRIT ETC OVER BEARINGS
1. Installation
Where should a boiler be located?
Ans. As near the engine as possible, as in fig. 1, at A.
Boiler Operation
293
Why?
Ans. To reduce pipe line condensation to a minimum and in
the case of super-heated steam, to minimize the super-heat loss.
How about the piping between the boiler and engine?
Ans. It should be as short as possible with minimum elbows
and adequate insulation.

INCLINED TOWARD ENGINE
RIGHT WAY
INCLINED TOWARD BOILER
WRONG WAY
Figs. 4 and 5.-Right and wrong way to pitch main steam pipe between boiler
and engine. The pipe should always be pitched to drain toward en-
gine, as in fig. 4, otherwise the condensate tending to return to boiler, as in
fig. 5, is opposed by the flow of steam in the opposite direction, resulting in
the accumulation of considerable condensate in the pipe, all of which, on a
sudden demand for steam, may be forced into the cylinder as a solid slug of
water with probably disastrous results.
294
Boiler Operation

DRIP
|
A
H
B
A
HEADER,
S
BOILERS
M
B
S
SMOKE
-FLUE
SMOKE
FLUE
BOILERS
DRIP
Fig. 6.-Objectionable arrangement of piping; it is arranged thus in order to
carry the bend D, underneath the crane girder in the engine room. It is
objectionable because when gate valve A on any boiler, is closed, bend B
will gradually fill with condensate, the column of water being driven over into
main when A is reopened. If engine be cut out of service by closing valve E,
leaving C open; bend D will fill up with water which will pass into the cylinder
when Ě is reopened. If both E and C, be closed, water will collect in main
above C. Whenever a valve forms a water pocket in a steam line, as A, C,
and E, the valves should be drained from above the seat.
ALTERNATE SCHEME WITH
ANGLE GLOBE VALVE
C
DIVISION WALL-
D
-CRANE GIRDER
DRIP
MAIN HEADER
D
DRIP:
ENGINE
E
G
F
ENGINE

CRANE GIRDER
E
X
DRIP
CONNECTION
ENGINE
DIVISION WALL
Fig. 7.-Proper arrangement of piping. In this arrangement, condensation on
bend C will drain into main; the same result is obtained using angle valve
(dotted lines) instead of B. Valves placed at same distance as H, above
boiler nozzle should be anchored to prevent vibration. Any leakage through
angle valve, or B, will fill bend E with condensate, hence the necessity of a
separator G, placed close to the cylinder.
Boiler Operation
295
Where should the main steam outlet on the boiler be
located?
Ans. At the end which will give the shorter pipe line between
engine and boiler.
The practice of the U. S. Navy on launches with compound engines
in having the l. p. cylinder next to the boiler and running extra length
of steam supply piping is in the opinion of the author ridiculous.

ROLLER
ROLLER
Figs. 8 and 9.-Method of preventing vibration and of supporting pipes. The
figures show top and side views of a main header carried in suitable frames fitted
with adjustable roller. While the pipe is illustrated as resting on the adjustable
roller, nevertheless the roller may also be placed at the sides or on top of the
pipe to prevent vibration, or in cases where the thrust for a horizontal or vertical
branch has to be provided for. This arrangement will take care of the vibration
without in any way preventing the free expansion and contraction of the pipe.
What important provision should be made in erecting
piping between boiler and engine?
Ans. It should be so inclined so that the condensate will
drain toward the engine.
296.
Boiler Operation
Why?
Ans. Because if the pipe be filled with condensate there would
be on opening the throttle, a bombardment of a solid column
of condensate to do damage in the absence of care in first
draining the pipe.
What Y
LARGE
PIRE
GOOD
VACUUM

TANGENT
INLET
CONDENSER
JW THI
MULTIPLICITY
OF CLOSE ELBOWS
2. Running
The term running as here used comprises:
1. Inspection before getting up steam.
SMALL
PIPE
POOR
VACUUM
CONDENSER
Figs. 10 and 11.—The right and the wrong way to pipe engine to condenser.
What mistake is usually made in the design of boiler
plants?
Ans. Usually there is no provision for equalized draught in
the case of a battery of boilers.
Boiler Operation
297
2. Getting up steam.
3. Firing methods.
4. Water tending.
5. Meeting fluctuating loads.
6. Banking fires.
7. Blowing off.

EXHAUST PIPE
30
2
.CONDENSER-
1.2.3.4,5.6 AND 7. MULTIPLICITY
OF CLOSE ELBOWS
6
Fig. 12.-An arrangement of exhaust piping which was expected to give a
24 inch vacuum, but didn't. The results obtained in this particular case was 12
to 15 inches. The only reasons for this arrangement were convenience, and
ignorance of conditions affecting back pressure.
What is the first thing an engineer should do on first
taking charge of a plant?
Ans. He should trace out all the pipe lines and note condi-
tion of same; carefully examine safety valve, gauge cocks and
water gauge, making sure that gauge column is clear of obstruc-
tions by inserting a rod.
Attention should also be given to feed line, check valve, feed pump,
injector, blow off valve.
298
Boiler Operation
What next should be done?
Ans. Fill boiler with water to proper level. Usually to 2nd
gauge cock.


BOILERS
-M
UNEQUAL DISTRIBUTION
BOILERS
NO DRAUGHT
DOOR
OPEN
DRAUGHI

DOOR
CLOSED:
Figs. 13 and 14.-Poor provision for draught in boiler room. Where the air must
come in through a door located at the end of the room, evidently the boiler
nearest the door will get most of the air and the others less and less, leaving
hardly any air for the most remote boiler. When the door is closed as in cold
weather, fig. 14, the draught in all the boilers will be very poor, the only air
available being that which leaks in through cracks.
Boiler Operation
299
How much water should be put in a small water tube
boiler and why?
Ans. Fill to top of gauge glass because a water tube boiler
holds very little water compared to a shell boiler, then in case
of trouble in starting pump or injector there is a margin of water
to work on.
Describe how not to get up steam, especially with shell
boilers.
Ans. Throw in all the wood the furnace will hold, saturate
the mass with kerosene and apply a match, starting the blower
full speed, as soon as possible.
What may be said of this method?
Ans. It indicates either ignorance or a desire to help the
repair man.
The fireman should understand the characteristics of the boiler he
is operating — what it will and will not stand.
What is the proper method of starting the fire?
Ans. Spread a thin layer of coal over the grate, then some
paper and a moderate amount of wood. It is best ignited by
burning some paper in the ash pan, or in the case of a large
boiler, some oily waste may be placed in the interstices of the
wood, as shown in fig. 15.
What precaution should be taken upon lighting the fire?
Ans. The draught should not be too strong, as unequal
expansion of the metal will cause leakage in the tubes, seams
or rivets.
What should be done as soon as the wood is well ignited?
Ans. Coal should be added, a little at a time.
300
Boiler Operation
Why should the coal be added a little at a time?
Ans. This will hold the fire in check and prevent sudden
heating of the metal.
After lighting the fire, what should be done?
Ans. Maintain a light fire until the brickwork of the setting
is dried out thoroughly. If the entire setting be new the drying
out may require several days; if the lining of the combustion

MATCH
ני הים
COAL PAPER
WOOD
יו
Th
Fig. 15.—Method of starting the fire. The thin layer of coal protects the grate
bars. The mass of wood is best ignited by lighting paper in the ash pan. In this
way ignition of the wood is secured in several places at once instead of only at
a single point.
chamber only has been renewed, about 48 hours will be suffi-
cient time for drying out for small settings. Larger ones will
require a longer time.
What should be done before steam begins to form?
Ans. Open top gauge cock or safety valve so that the steam
will drive out the air.
Why?
Ans. The air, if not removed, would work through to the
condenser and retard the vacuum, moreover its presence would
furnish oxygen which would be active in corroding the boiler.
Boiler Operation
301
Why open gauge cock instead of the safety valve?
Ans. Air, being heavier than steam, will be next the water,
while the steam will rise, hence the air should be expelled at a
point as near the water line as possible. See fig. 16.

@THIN
|:
PUERILEH
STEAM
AIR
1-101
IgH
121-1
Fig. 16.-Method of expelling air from boiler in getting up steam. Air being
heavier than steam, will lie in a layer next to the water line, while steam will
rise to the top, hence to get out all the air open the water gauge cock (nearest
above water line) and not the safety valve.
When steam forms what should be done?
Ans. The safety valve and gauge cocks should be closed, and
the steam gauge should at once be observed.
What attention should be given to the water gauge?
Ans. If it appear stationary or "dead" see that the valves
are open.
302
Boiler Operation
What is a good indication that the water gauge is
working?
Ans. A "lively" gauge-that is the water fluctuating up and
down, especially, in water tube boilers.
What does a too lively gauge indicate?
Ans. Priming or foaming.
What should be done when steam is up to the desired
pressure and no steam is being used.
Ans. The hinges of the fire door should not be dislocated or
broken off by violently throwing the fire door open as is usually
done by greenhorns.
How is a further rise of pressure and blowing off avoided?
Ans. Close the damper and throw on a little coal, being care-
ful to spread it well.
Why not throw open the fire door to check the fire?
Ans. When the door is opened, the sudden inrush of cold air
striking the highly heated surfaces cause rapid cooling of the
metal with unequal contraction, this, in the case of a shell
boiler, subjecting it to severe strains, in some types of pipe
boilers it makes no difference.
Why should the ash pit door be left open at all times?
Ans. To prevent the grate bars becoming overheated, thus
prolonging their life.
In general how is the fire attended after raising steam?
Ans. For power boilers, frequent firing in small amounts; for
house heating boilers, heavy firing with less frequent intervals.
Boiler Operation
303
There are two kinds of firing:
1. By hand;
2. By mechanical stokers.
121/2"
What are the various methods of hand firing?
Ans. 1, Spreading methods: (a. even spread; b, alternate side
spread; c, alternate front and back spread;), 2, coking method.
Describe even spread firing.
Ans. The coal is spread evenly beginning at the back of the
grate and working toward the door, as shown in fig. 20.
WELDED
1
22"
P
WELDED
+2½"
WELDED
3. Firing

3/4"
·6'-6"
8'
I" STANDARD PIPE
8'
I" ROUND BAR WELDED
TO END OF PIPE AND
BLADE RIVETED TO IT.

WELDED
14" STANDARD PIPE
I" STANDARD PIPE
•
-2-6″
22"

WELDED
|6
Figs. 17 to 19.-Fire tools as recommended by the Bureau of Mines showing
construction and dimensions.
304
Boiler Operation
Describe the alternate side spread firing.
Ans. Coal is spread on one side of the grate over its whole
length, then over the other side, alternately, as shown in figs.
21 and 22, at equal intervals of time. The firing interval is short-
ened to one half the time as with the even spread method.
Describe alternate front and back spread firing.
Ans. This method is the same as the alternate side spread
method except that the fresh coal is alternately fired on the
front and back halves of the grate.

-
wang
Fig. 20-Even spread mode of firing, the result of which will be a uniform genera-
tion of gas throughout the charge.
What is the coking method of firing?
Ans. In this method the fresh coal is piled on the front of
the grate, while the rear half is covered with partially burned
coke. See figs. 23 and 24.
What is the action of the coking method?
Ans. The gases distilled from the fresh coal pass over the
rear half of the grate, through which an excess of air is enter-
ing, the air being highly heated as it passes through the bed of
Boiler Operation
305
coke. The gases and heated air intermingle in the combustion
chamber and are completely burned to carbon dioxide and
steam.
}
Kox /\ /\ \\ /\.
Which is the more efficient, the spreading or the coking
method of firing?
Ans. The spreading method.

(6)
Kow!
Kyk m
Figs. 21 and 22.—Alternate side spread firing. Fig. 21, fresh coal put on right
side; fig. 22, fresh coal put on left side. The coal should be fired in small
amounts and well spread. In some cases a boiler that requires a fire on both
sides, say every 10 minutes, will require a fire on the right side every 10 min-
utes, and on the left every 10 minutes, making 5-minute intervals between fir-
ings. The gas given off by the fresh coal on one side rises into a hotter furnace
or combustion chamber (than it would if both sides were fired simultaneously)
on account of the hot, clear fire on the opposite side, and the result is that most
of this gas is burned if the proper amount of air be admitted through the door.
When the last side fired burns clear, the opposite side is fired, thus the clear fire
on one side serves to ignite the gases baked out of the fresh coal on the other
side.
How should coal be fired in the spreading method?
Ans. In small quantities at short intervals.
Why?
306
Boiler Operation
A


BRIDGE WALL
WEEEEE
E
Figs. 23 and 24.—Coking method of firing. Fresh coal is placed just inside the
furnace door on the dead plate, covering a few inches of the grate as in fig. 23.
The draught plate in the fire door is left partly open so as to admit air to the
fresh coal. The heat of the fire gradually bakes the volatile matter out of the
coal and if this be mixed with the proper quantity of air entering through the
door a considerable proportion of the mixture can be burned. When the fire
needs more fuel the pile just under the door is spread over the incandescent coals
with a hoe, as in fig. 24. The pile of coal is thus reduced to coke which burns
without smoke, after spreading a new charge of coal in place on the front of
the grate and dead plate.

I__-&-+-----
12" TO 18"
·4'-6".
SE
COAL CAR
---2~~
Fig. 25. Proper position for firing. According to the Bureau of Mines,
the fireman should stand in such position that he can see the thin spots and can
throw the coal onto them with the least effort. He should stand 4½ to 5 feet in
front of the furnace, and 12 to 18 inches to the left of the center line of the door.
He should then be about 2 feet from the coal, which is 6 or 7 feet from the furnace
front and should preferably be on a car.
Boiler Operation
307
Ans. So that thin places do not burn through and admit
large excess of air.
What are the reasons for light and frequent firing?
Ans. When fresh coal is fired, the volatile matter is imme-
diately distilled. The process is nearly completed in 2 to 5 min-
utes, therefore immediately after firing, large quantities of air
should be admitted over the fire. After 2 to 5 minutes it should
be cut down. Such regulation is practically impossible, hence
large quantities of fuel should not be fired at one time.
կլ

STOP
BOILER
M
Fig. 26.-End of the throw. The scoop should travel in a nearly straight line.
At the end of the throw, the scoop should suddenly be stopped by laying it on
the bottom edge of the door frame. The coal then flies off and is scattered over
the proper spot. By thus stopping the scoop, the fireman saves effort, and locates
the coal better. If he push the scoop way into the furnace, he has to jerk it back
to get the coal off.
Where are thin spots especially likely to occur?
Ans. In the corners at the front of the furnace and between
the firing doors.
How does a skilled fireman treat thin spots?
Ans. He gauges the right amount and selects the proper
mixture of fine and coarse coal.
308
Boiler Operation
When and why is coarse coal used?
Ans. When the spot is burned way down to the grate. The
coarse coal avoids sifting through the grate.
What is the objection to a thin fuel bed?
Ans. Too much attention is required to prevent holes, because
when holes form, too much air flows through without uniting
with the carbon.

BRIDGE WALL
PATH OF SCOOP
2'OR
MORE
COAL CAR
Fig. 27.-Improper position in firing. If the coal be closer than 6 or 7 feet,
the fireman is crowded and will stand away to one side of the door to avoid the
intense heat. He cannot see the fire, and throws the coal in by guess. His scoop
travels in the arc of a circle, scattering coal on the floor, and dumping it in a
heap directly inside of the door. This results in an uneven fire, low efficiency, and
requires raking of the coal onto the back part of the fire. Provide a smooth firing
floor, or a smooth bottom to the coal car, so that the shovel does not hit bumps
and rivets. Such items delay the firing operation, keeping the door open longer
than necessary and admitting excess air.
With a given draught how can the rate of combustion
be increased?
Ans. By reducing the thickness of the fuel bed.
Boiler Operation
309
What is the object of wetting coal?
Ans. To cause the coal to burn slower, thereby giving the
gases a better chance to mix with the air.
What happens when coal is first thrown on the fire?
Ans. It gives off gas faster than it can be brought into con-
tact with the necessary amount of air for complete combustion.

SURNED OUT
GRATE BARS
Vo
kerul
>>>>>>>>>2}}}
IEESUSCI
unifomon
Fig. 28.-Usual condition of the ash pit when the owner cannot put off taking up
the ashes any longer. Note the burned out grate bars due to letting ashes
accumulate in the ash pit. The illustration does not show the new grate just
ordered from the plumber, but it is on the way.
Mention an objection to wetting coal.
Ans. The water must be evaporated and this wastes heat.
What difficulty is experienced in burning bituminous
slack coal?
310
Boiler Operation
Ans. It fuses into a hard tight crust which admits little air,
resulting in a low combustion rate.
What is done to correct this in firing?
Ans. The crust should be broken by lifting with a slice bar
and then level the fire.

17-
Fig. 29.-Firing soft coal in 6x9 vertical marine boiler of author's steamer
Atlantic City," showing small hole in door, through which slice bar is in-
serted to break up the fuel. The shutter, loosely pivoted above the hole, falls
into place, closing the hole after the bar is removed. This arrangement will be
found of great help in firing soft coals.
Boiler Operation
311
What was the method of firing soft coal in the author's
steamer "Atlantic City"?
Ans. A small hole was cut in the fire door and provided with
a hinged flap. The metal around the hole acting as a fulcrum for
working the slice bar.
The flap being loosely
hinged drops shut on
removal of the slice
bar. See fig. 29.

FLAT
FRONT WEDGE
SONT
REAR WEDGE
What must be done
periodically in
firing?
Ans. The fire must
be "cleaned."

Define the term
"cleaning the fire."
Ans. By definition:
The operation of remov-
ing clinkers, cinders,
etc., from the burning
coal at regular intervals.
Figs. 30 to 32.-Firing with hard (anthracite) coal. 1. Flat method. 2. Wedge
method with thin fuel at the front. 3. Wedge method with thick fuel
at the front. These methods give good results when the fires are properly
handled.
312
Boiler Operation
Why is this frequently necessary?
Ans. Because the clinker and coarse ash will not pass through
the grate.
What tools are used for cleaning the fire?
Ans. The hoe and slice bar and the rake for leveling the fuel
bed. See figs. 17 to 19.
Upon what does the intervals between cleaning depend?
Ans. Upon the proportion of ash in the coal and the type of
grate.


→
ے
DPD
CLINKERS
HOE
ADA
Co
CLINKERS
SADD
8888
DODAR
LVADO
Did
48
OD
DODODA
BATA
A
Bor
4
00
DO
2000
SLICE BAR
Figs. 33 and 34.-Side method of cleaning the fire. See note page 313.
Boiler Operation
313
Name two methods of cleaning the fire.
Ans. 1, The side method; and 2, the front to rear method.


CLINKERS REMOVED
N
0.0.
3:0
ว
COR
0
ว
( ว ว
RIGHT HALF
PUSHED
.BACK
CLINKERS
REMOVED
0
RIGHT
HALF
LEVELED
LEFT HALF
PUSHED BACK
Figs. 35 and 36.—Front to rear method of cleaning the fire. See note page 314.
NOTE.-Side method of cleaning fire. In this method one side of the fire is
cleaned at a time. The good coal is scraped and pushed from one side to the other.
The clinkers may have to be removed from the grates by the slice bar. When they
have been loosened and broken up, they are scraped out of the furnace with the
hoe. The fireman should gather the clinker on the front part of the grate before
pulling it out into the wheelbarrow, as this saves him from exposure to the heat.
After the one side is cleaned, the burning coal from the other is moved and scraped
to the clean side. It is spread evenly over the clean part of the grate, and a few
shovelfuls of fresh coal are added, in order to have enough burning coal to cover
the entire grate when the cleaning is done. This adding of coal is important,
especially when the cleaning must be done with the load on the boiler. The
clinkers are then removed from the second half of the grate. When cleaning is
started, there should be so much burning coal in the furnace that enough will be
left to start a hot fire quickly, when the cleaning is completed. If a light fire be
carried it may be necessary when starting to clean to put some fresh coal on the
side to be cleaned last. During cleaning, the damper should be partly closed.
A fireman after becoming familiar with the side method should be able to clean
a 200 h.p. boiler furnace in 10 to 12 minutes.
314
Boiler Operation
Firing with Coke
What are the requirements for complete combustion of
coke?
Ans. Coke needs a greater volume of air per pound of fuel
than coal, and therefore requires a stronger draught, which is
increased by the fact that it can only burn economically in a
thick bed.
What else should be considered?
Ans. It is necessary to take into account the size of the
pieces. For a given combustion rate about 3 more grate area
is required with coke than with coal.
Firing with Coal Tar
What is the chief difficulty of firing with coal tar?
Ans. It is difficult to get a constant flow of tar into the
furnace.
NOTE.-Front to rear method of cleaning the fire. In this method the
burning coal is pushed with the hoe against the bridge wall. It is usually preferable
to clean one-half of the grate at a time. The clinker is loosened and pulled out of
the furnace and the burning coal is spread evenly over the bare grates. If the front
to rear method must be used while the load is on the boiler, the side method
should be employed after the day's run is over, so as to prevent the large accumu-
lation of thick and hard clinker at the bridge wall. Some firemen have the habit
of pulling the clinkers out of the furnace without scraping and pushing the burn-
ing coal against the bridge wall or to one side. This really is not a method of
cleaning the fire. They run a slice bar under the clinker to lift it to the surface
of the fuel. Then they take a hoe and pull the large pieces out. The small pieces
are not easily detected and are left in the fire. These fuse in a few minutes, due
to the high temperature near the surface of the fuel bed, and then run into the
grates. Thus more masses of clinkers are formed, which are usually worse than
those previously removed. This habit should be discouraged.
Boiler Operation
315
What are the causes of these difficulties?
Ans. Stoppages caused by the regulating cock or other ap-
pliance not answering its purpose and by the carbonizing of
the tar in the delivery tube, thus choking it up and rendering
it uncertain in action.
How may these difficulties be overcome?
Ans. Fix the tar supply tank as near the furnace to be sup-
plied as convenient, and one foot higher than the tar injector
inlet. A cock is screwed into the side of the tank, to which is
attached a piece of composition pipe 3/8-inch in diameter, 10
inches long. To this a 12-inch iron service pipe is connected,
the other end of which is joined to the injector.
What results are obtained by this arrangement?
Ans. It is found that at the ordinary temperature of the tar
well (cold weather excepted) four gallons of tar per hour are
delivered in a constant stream into the furnace.
How is the risk of stoppage in the nozzle overcome?
Ans. By the steam jet, which scatters the tar into spray and
thus keeps everything clear.
Firing with Straw
At what rate should straw be fed into a furnace?
Ans. Only as fast as needed.
What is the nature of the flame when the straw is rightly
handled?
Ans. It makes a very hot flame and no smoke is seen coming
from the stack?.
316
Boiler Operation
What is the important point in burning straw?
Ans. The best results are obtained from this fuel when it is
fed into the furnace in a gradual stream as fast as consumed
this results in complete combustion. See fig. 37.

f
WA WACHINEMA LE
ACHI CHAQI
AIR INLET
FOR STRAW
1232352
Fig. 37.-Furnace for burning either straw or solid fuel. In operation, the ash
pan damper being raised, a current of air flows into the fire box as indicated by
the arrows.
Firing with Saw Dust and Shavings
Describe the method of firing with this fuel.
Ans. The shavings are forced through a 12-inch pipe into the
combustion chamber. The pipe is provided with a blast gate to
regulate the air in order to maintain a pressure in the furnace.
Boiler Operation
317
In what manner are the shavings forced into the com-
bustion chamber and why?
Ans. In a spray like manner so as to quickly ignite the
oxygen in the air forced into the furnace along with the shavings,
giving full support for combustion.
What precaution should be taken?
Ans. It is important to keep the blower going continuously
to prevent the flames going up the chutes, thence through the
small dust tubes leading from the bin to the various machines.
Firing with Tan Bark
How can tan bark be mixed?
Ans. By mixing with bituminous screenings tan bark can be
burned upon ordinary grates and in the ordinary furnace.
What proportion of these fuels should be used?
Ans. One shovelful of screening to four or five of bark will
produce a more economical result than the tan bark separate,
as the coal gives body to the fire and forms a hot clinker bed
upon which the bark may rest without falling through the
spaces in the grate bars and with the coal, more air can be
introduced into the furnace.
What should be noted about tan bark as to efficiency?
Ans. The drier it is the more valuable it is as a fuel.
318
Boiler Operation
Points Relating to Hand Firing
How do you begin to charge the furnace?
Ans. Begin at the bridge end and keep firing to within a few
inches of the dead plate.
What precaution should be taken as to timing firing
intervals?

――
Jay
Hook
HO
LAZY
BAR
Fig. 38. The lazy bar. By its use the labor of cleaning the fire is greatly reduced,
especially with flat grates and deep fires. When cleaning a fire, the lazy bar
serves as the fulcrum for the hoe, instead of the bottom of the fire door. Thus
the hoe or rake can be kept in a horizontal position when pushing the live coals
back against the bridge wall or drawing clinker forward to the door, and at the
same time the hoe does not rest on the fire and drag along over it.
Ans. Never allow the fire to be so low before a fresh charge
is thrown in, that there shall not be at least three to five inches
deep of clean, incandescent fuel on the bars, and equally spread
over the whole.
Boiler Operation
319
How should the firing be done?
Ans. Keep the bars constantly and equally covered, particu-
larly at the sides and the bridge end, where the fuel burns
away most rapidly.
!!!!!!
What should be done if the fire burn unequally or into
holes.
Ans. It must be leveled, and the vacant spaces must be filled.


D
10
TIP.
O
}
"1
00
STEAM
JET
A
Figs. 39 and 40.-One method of smoke prevention by means of a steam jet.
The jet is located just above the fire door as shown. After each firing the jet is
opened a few minutes which prevents black smoke, reducing its density to a
haze.
What should be done with large coals?
Ans. They must be broken into pieces not bigger than a
man's fist.
What is the procedure with respect to a shallow ash pit?
Ans. It must be more frequently cleaned out. A body of hot
cinders, beneath the bars, overheats and burns them.
How about the firing intervals?
Ans. The fire must not be hurried too much, but should be
320
Boiler Operation

KAINUUMIMINKAMARALARMURAT JANAEakum útmuELLAANGBARNABANNE AMIDIHAL JILLE BETALE LAUKKUMATIKKAUTTA
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Fig. 41.-Method of observing the top of the stack from boiler room. By means
of a mirror fixed at a suitable angle, the fireman can, while firing, note the
smoke indications. The device will be found helpful in securing more efficient
combustion.
Boiler Operation
321
left to increase in intensity gradually. When fired properly the
fuel is consumed in the best possible way, no more being
burned than is needed for producing a sufficient quantity of
steam and keeping the steam pressure even.
How should the draught be regulated?
Ans. By the damper, not by closing the ash pit doors.
How should the fire be checked?
Ans. By the damper, and not by throwing open the fire doors.
Hints to Locomotive Firemen
The following suggestions will be found helpful to the loco-
motive fireman.
1. Anthracite coal must be fired to suit the size of the lumps used.
2. If the coal be in coarse lumps weighing about eight pounds each,
a thick fire must be carried, for the lumps lie so open that the air would
pass so freely through that it would chill the fire box.
3. A thin fire of anthracite coal cannot be carried.
4. In firing lump coal of large size, even with a thick fire, constant
care is necessary to prevent loss of heat from excessive amount of air
passing through holes.
5. There is a constant tendency for air passages to form close to the
sheets, hence the fire should be heavier here than at other parts.
6. Too much air admitted through the fire tends to reduce parts of
the fire box below the igniting temperature.
7. Firing with large lumps is wasteful with either hard or soft coal.
8. For small sizes of anthracite a very large grate area is necessary,
because the fire must be thin, which precludes a strong exhaust unless
the blast be divided over a wide area.
322
Boiler Operation
!
9. In using soft coal do not carry over ten or twelve inches of fire in
the center of the fire box; keep the sides and corners a little higher;
aim to fire in the corners and sides more than in the center.
10. If the boiler will not steam well with a light fire, more air is
probably needed at the front of the box. Leave the fire door open a little
way for a few seconds after putting in coal; it helps to consume the
smoke.
11. Two shovelfuls of coal is enough at one time if put on the bright
spots. No boiler will steam well with the fire box and flues full of smoke.
12. If necessary to use the hook be careful not to mix the green coal
with that partly consumed.
13. Do not use a slice bar if it can be avoided.
14. Be careful not to get green coal on the grates.
15. If the fire box have an arch, keep a good space open between the
arch and the fire.
16. If the train be heavy, it will need a heavier fire than with a
light train and a fast run; always make calculations to fire according
to train and speed.
17. Hook out all clinkers from the fire as soon as you find them.
18. Do not fire much while pumps or injectors are on full.
19. If the engine have ash pan dampers use them when necessary.
20. If there be more steam than is needed, the dampers should be
closed; a certain amount of air is necessary to make a fire burn as it
should; if too much air be admitted, the gases will be chilled; if too
little, they will not ignite; no rule can be made for the exact amount of
air required, because different kinds of coal require varying quantities
of air; only keep a bright fire low in the center of the box where the
most air is needed and watch when the greatest flame appears in the
fire box with the least smoke going out of the stack; attend to the
fire often.
Boiler Operation
323
In taking an examination for engineer's license what is
usually the first question the examiner asks?
Ans. "What is the first thing you would do on entering the
boiler room"?
n
Well, what would you do?
Ans. I would find out if there was the proper amount of water
in the boiler.

Clan
W
j.ll
1
}
Ms the M T W
G. Wh
Figs. 42 and 43.-Firing shavings by hand. For hand firing it is necessary to
burn the shavings from the top as otherwise the fire and heat are only produced
when all the shavings are charred. To do this, provide a half-inch gas pipe, to
be used as a light poker; light the shaving fire, and when nearly burned take
the half inch pipe and divide the burning shavings through the middle, banking
them against the side walls, as shown in fig. 42. Now feed a pile of new shav-
ings into the center on the clean grate bars, as shown in fig. 43, and close the
furnace doors. The shavings will begin to burn from above, alighted from the
two side fires, the air will pass through the bars into the shavings where it will
be heated and unite with the gas, making the combustion perfect, generating
heat, and no smoke, and the fire will last much longer and require not half the
labor in stoking.
What is the proper amount of water?
Ans. The water level should be high enough to submerge all
heating surfaces exposed to intense heat, the exact level de-
pending upon the type of boiler.
324
Boiler Operation
Does the water gauge show the true level of the water
in the boiler?
Ans. No.
Why not?
Ans. Because the density of the cold water in the glass is
M


·CLEANING PLUGS
รา
O
O
TO
BOILER
WATER COLUMN
TO
BOILER
TRUE
LEVEL·
FALSE
LEVEL
HEMISEMINEMISH |
COLD,
HEAVY
WATER
HOT, LIGHT
WATER
S
Fig. 44.-Proper method of connecting water column to boiler. By the use of two
crosses and plugs the entire system is made accessible for internal cleaning
which is important. Thus by removing plugs M and S, the column may be
cleaned, and by removing L and F, the connections to boiler. Preferably a
cock should be used instead of plug S, which would permit frequent blowing
off of the column and facilitate draining when laid up in cold weather.
Fig. 45.-False water level due to difference in density of the cold water in
the gauge glass and the hot water in the boiler. The difference between the
two levels is considerably exaggerated for clearness, in reality this difference
is very small and may be disregarded.
Boiler Operation
325
greater than the hot water in the boiler, causing a thermal
equilibrium upset, as in fig. 45.
What is the indication that the water gauge is not
working?
Ans. A stationary water level.
What should be done to correct this?
Ans. Open drain cock wide till all water disappears from the
SEPARATOR
DRAIN
WATER
LEVEL
BAFFLE PLATE
COLLECTOR
kthr€
EXIT
DRYER

SEPARATOR
Fig. 46.-Detail showing upper tube sheet, separator, collector and dryer of the
Graham boiler.
glass, then close and if gauge be cleared of any foreign matter
water will rise at once to proper level.
What other condition indicates that the gauge is work-
ing properly?
Ans. A "lively" water level, that is the level will fluctuate
up and down more or less depending upon the type of boiler,
being especially lively in a water tube boiler.
How should steam be raised in a vertical tubular boiler
with through tubes?
326
Boiler Operation
Ans. To prevent burning the tubes the boiler should be
entirely filled with water, leaving a vent by raising the safety
valve or blocking open whistle valve to allow for expansion of
the water as it is heated.
How high should the water be carried in a vertical boiler,
and why?

BOILER
BY PASS
ΣΗ
HOT WELL
*R
OB
о
FEED
PUMP
S
REDUCTION
GEAR
vv
ENGINE SHAFT
Fig. 47.—Ideal method of constant feed especially in marine plants. The con-
densate delivered from condenser to hot well is pumped into boiler by the
feed pump. Since the latter of necessity has excess capacity, a by pass valve
M, is provided so that the excess may be returned to the hot well, otherwise the
hot well would soon empty and the pump would force both water and air into
the boiler. By close adjustment of valve M, the water is pumped into the boiler
at the same rate it is delivered to hot well by the air pump, thus the inlet remains
covered with water preventing any air being carried over into the boiler. In
time the water level in the boiler gradually falls, due to loss of water through
stuffing boxes, whistle and safety valve, and this may be made up by closing
M, and opening make up valve S. When the water rises to the normal level, S,
is closed and M, again adjusted. By providing a small valve R, in the by pass
pipe this valve may be used to shut off the by pass so that when the correct
adjustment of M, has been found, it need not be again disturbed. Valve M, is
used when regrinding is necessary for the needle valve R.
im
Boiler Operation
327
G
Ans. As high as can be without causing wet steam, because
it increases the efficiency of the heating surface, and prolongs
the life of the tubes.
In the author's boiler he has provided a separator, collector, and
dryer to permit carrying abnormally high water level, as shown in
fig. 46.
What is the advantage of the abnormally high water
level in the boiler?
Ans. It protects the tubes and increases efficiency of the
tubular heating surface.
How should water be fed to a boiler?
Ans. It depends upon the type of boiler, for instance, constant
feed, for a marine boiler and intermittent feed for a locomotive.
See fig. 47 for constant feed.
Why intermittent for a locomotive boiler?
Ans. In descending a long grade with throttle closed, the
boiler may be filled to top gauge cock and then shut off, so
that during the ascent of the next grade where maximum
amount of steam is needed, the evaporation is not reduced by
the admission of cold feed water.
In marine practice what means are provided to prevent
loss of feed water by the safety valve blowing off?
Ans. A "bleeder" or connection between boiler and con-
denser, as shown in fig. 48.
How is the bleeder operated?
Ans. The bleeder valve is opened, allowing steam to blow into
the condenser, the condensate being pumped into the hot well
by the air pump, thence back into the boiler by the feed pump.
328
Boiler Operation
What is necessary for bleeder operation?
Ans. Independent air and feed pumps, or in case of engine
driven pumps, the engine must be run slowly to relieve the
condenser of condensate.
What are the indications that a feed pump is working?
Ans. The check or check valve noise each time the valve
seats; also, the low temperature of the pump and feed line as
indicated by feel and coating of condensate on the pump barrel
and line. See fig. 49.

CONNECT CLOSE TO THROTTLE
TO PREVENT ACCUMULATION
OF CONDENSATION.
BLEEDER
EXHAUST
THROTTER
Fig. 48.-Combination of bleeder and main steam pipe drain. It provides
means of preventing water loss by safety valve blowing, also for draining and
warming the steam pipe before starting the engine.
What are the indications that the feed pump is not
working?
Ans. No check valve noise and warm temperature of the
feed line.
What does the warm temperature of the feed line indi-
cate?
Boiler Operation
329
Ans. It indicates a back flow of water from the boiler due
to check valves not properly seating.
If on entering the boiler room you would find the water
out of glass, safety valve blowing off strong, and a good,
hot fire under boiler, what should be done?
Ans. First, the fire should be smothered as quickly as possible
with wet ashes, earth or coal, closing ash pit doors and leaving

↓
CONDENSATION
ON PIPE
CLICK
FEED
PUMP
200
FEELS COLD
BOILER
CLICK
•11
RELIEF
VALVE
GLOBE
VALVE
Fig. 49.-Feed pump piping and indications of proper operation.
furnace doors and damper open. If now it be found that the
water has not fallen below the level of either the crown sheet or
other extended area of heating surface, the feed pump may be
started with perfect safety, but if this certainty cannot be
assured, the boiler must be cooled down completely, carefully
inspected, and repaired if necessary. If no part of the exposed
metal be heated to redness, there is no danger except from a
rise in the water level sufficient to flood the overheated metal.
Hence, care should be taken that the safety valve be not raised
so as to produce a priming that might throw the water over the
330
Boiler Operation
overheated metal, and that no change be made in the working of
either engine and boiler that shall produce priming or an in-
creased pressure.

RED MOT
'(.l.
VERY LOW WATER LEVEL
Da
MAINT
تیزم تا
RISING WATER LEVEL
"l
.)
RAPID GENERATION OF STEAM IN EXCES
OF SAFETY VALVE CAPACITY
:((
fir
3 A
EXTENDED AREA OF HORIZONTAL
HEATING SURFACE FLOODED
Figs. 50 and 51.-Sectional view of locomotive boiler with dangerously low
water level, illustrating why the feed pump should not be turned on. With the
feed pump in operation the water level gradually rises and when it reaches the
elevation of the crown sheet this extended area of heating surface (now red
hot) becomes suddenly flooded with water with the result that steam is gener-
ated quicker than can be discharged by the safety valve, hence the pressure
rises, bringing more strain on the crown sheet already weakened by the excess
heat, and therefore increasing the chances of an explosion.
If any portion of the boiler plate be red hot, an additional danger is
due to the steam pressure, which should be reduced by continuing the
engine in steady operation while extinguishing the fire. If the safety
valve be touched at such a time it should be handled very cautiously,
allowing the steam to issue steadily and in such quantity that the steam
gauge does not show any sudden fluctuations while falling. The damping
of the fire with wet ashes will reduce the steam pressure very promptly
and safely.
Boiler Operation
331
What is priming, and what causes it?
Ans. A boiler primes when it lifts the water level and delivers
steam containing spray or water as in fig. 52. It is usually
caused by forcing a boiler too hard or by a too high water level,
or a combination of both these causes.
When a boiler primes violently it may be necessary to close all
outlets to find the true water level.
PRIMING
HEAVY DEMAND
SPRAY
WATER LEVEL
ABNORMAL
NORMAL
FOAMING
DIRTY WATER
BEERLIKE FOAM

ANAS

POORLY DEFINED
WATEP LEVEL
Figs. 52 and 53.-Elementary boilers illustrating the difference between prim-
ing and foaming, and the conditions which produce these effects.
What is foaming, and what causes it?
Ans. Foaming is severe priming or agitation of the water
level due to dirty or impure water, as shown in fig. 53.
In case of fire in the building, what should be done?
Ans. Haul fire from under boiler, start fire tank pump and
abandon boiler room.
332
Boiler Operation
If fire had gained such headway that there was no time
to haul fire from under boiler, what should be done?
Ans. Open furnace doors, start feed and tank pump full
speed and abandon boiler room.
In case building had its own electric plant, the engine should be left
running.
If the soot deposit on the heating surface be not re-
moved, what happens?
Ans. The increasing accumulation of soot interferes with the

Fig. 54.-Section of boiler plate at a riveted joint, showing the effects of corro-
sion of the metal. The normal surface of the plate is indicated by the dotted
line across the opening of the corroded gap.
STEAM

HIGH
LEVEL
SURFACE ATTACKED
BY THE AIR
LOW
LEVEL
{(c
1.
WATER
CAIR
Fig. 55.-Corrosion along the water line due to air. Even the most nearly pure
water, when containing air, will cause corrosion. Air, since it is heavier than
steam, forms a layer between the water and steam and rapidly corrodes the
plate along the water line. Accordingly, care should be taken to prevent the
feed pumps drawing in air.
Boiler Operation
333
draught and considerably reduces the amount of heat trans-
mitted to the water.
How is the accumulation of soot indicated?
Ans. By an increase in the temperature of the chimney gases.
Soot is almost the best insulator known, hence the necessity of
keeping the heating surface clean.
What is corrosion?

}
ľ
Fig. 56.—Water leg of vertical boiler showing corners of the shell and furnace
plate at the level of the foundation ring.
Ans. Chemical action which causes destruction of the surface
of a metal by oxidation; rusting.
What part of the boiler is especially susceptible to cor-
rosion and why?
Ans. Corrosion occurs especially along the water line because
the air in the water on being given up during evaporation, being
heavier than the steam, collects in a layer between the water and
the steam and attacks the metal at this point. See fig. 55.
334
Boiler Operation
+
What part of the furnace shell is especially subject to
corrosion?
Ans. The space between the grate and the furnace shell.
Why?
Ans. Dampness and the lye of the ashes attacks the furnace
shell.
What should be done?
Ans. Clean thoroughly with a wire brush on laying up and
give it a coat of red lead mixed with raw linseed oil.

Fig. 57.-Corrosion of boiler shell along seam. This eating away of the plates
is due to the chemical action of impure water. Gases absorbed by water, such
as sulphuretted hydrogen and carbon dioxide are very active in the corrosion of
boiler plates. Grease and organic matter also promote corrosion.
What is pitting?
Ans. A form of corrosion resulting in a series of minute holes
or "pits" eaten into the surface of the metal to a depth of
sometimes one quarter of an inch.
Pitting is the more dangerous form of corrosion.
What condition especially causes pitting?
Ans. When a boiler is merely warm, pitting and corrosion
occur to a much greater extent than when under pressure.
Boiler Operation
335
What is frequently used in boilers to prevent the cor-
rosive action of water on the metal?
Ans. Zinc.
-
How is the zinc placed?
Ans. Slabs of zinc are suspended in the water by means of
wires which are soldered to the upper part of the shell so as to
make electrical connection.
Explain the action of the zinc.
Ans. The zinc forms one element of a galvanic battery and
the metal of the boiler the other, with the result that the zinc
is eaten away and the iron is protected.
Give a test for corrosiveness.
Ans. Fill a tumbler nearly full of water then add a few drops
of methyl orange. If the water be acid and corrosive it will be-
come pink, but if alkaline and harmless it will turn yellow.
What is incrustation?
Ans. A coating over, the coating, being commonly known as
scale.
Describe the formation of scale.
Ans. Water, on becoming steam, is separated from the im-
purities which it may have contained, and these form sediment
and incrustation.
What is the effect of oil carried into the boiler?
Ans. Minute globules of oil coalesce to form an oily scum on
the surface of the water. Some globules come in contact with
solid scale forming particles and when they have the same
336
Boiler Operation
specific gravity as the water, they rise and fall with the con-
vection currents and stick to any surface with which they
come in contact.
What is the proper method of eliminating scale?
Ans. Some reagent should be used which will precipitate the
scale-forming ingredients and soluble salts, and convert them
into insoluble salts without increasing the total amount of solids.
What two methods are employed?

SCUM SCOOP
SCUM COCK
Fig. 58.-Scum scoop or surface blow for blowing out fine particles of foreign
matter floating on the surface of the water.
Ans. By treating the feed water before it enters the boiler,
or by putting the chemicals into the boiler direct.
What about the use of kerosene in boilers?
Ans. It prevents the particles of scale sticking closely to-
gether or adhering to the heating surface.
How is an accumulation of deposits prevented?
Ans. By a frequent use of the bottom blow.
What is a scum scoop?
Ans. Apparatus for blowing out water from the surface to
remove fine particles of scale forming foreign matter. See fig. 58.
Boiler Operation
337
How is the presence of oil in the boiler indicated?
Ans. It shows in the glass water gauge when in large amounts,
but a boiler may contain a dangerous amount of oil without this
indication.
How may the oil be reduced?
Ans. By boiling out the boiler with kerosene and soda ash,
or by scraping and scrubbing, or a combination of these two
methods.

]••••••]]
A37.
ky
Fig. 59.-Horizontal tubular boiler showing where scale accumulates most
rapidly.
What precautions should be taken when treating a
boiler with kerosene?
Ans. Keep all lighted candles, lamps or other fire away from
the boiler openings, both when applying the kerosene and upon
opening the boiler again.
What is blowing off?
Ans. The act of letting out water and steam from a boiler to
carry off accumulated mud and scale.
When should the boiler be blown off and why?
Ans. The blow off valve should be opened in the morning
338
Boiler Operation
1
while the fires are still banked, because a considerable amount
of sediment will have settled down during the night.
Suppose the boiler be used both night and day?
Ans. Blow off at the end of the noon hour shut down period.


MAMAYATHRIEN
O
Figs. 60 to 64.-Accumulation of scale between the ends of tubes and on the
surface of tube sheets. One patch of thick scale in proper place can retard
the flow of water as thoroughly as a much larger area of very thin scale. It acts
as a dam or baffle between the tubes of a fire tube boiler and in the tubes of a
water tube boiler.
KA
How should the blow off valve be opened and closed and
why?
Ans. Gradually so as to avoid sudden shock.
The valve should be opened fully.
Boiler Operation
339
How much and how often should a boiler be blown down?
Ans. At least "one cock" a day depending upon the amount
of sediment forming.
What precaution should be taken in closing the blow off
valve?
Ans. Observe the end of the blow off pipe and see that the
valve is tightly closed.



1

19
Figs. 65 to 68.-Forms of nozzle for washing out boilers.
What should be done before cleaning a boiler?
Ans. Drain boiler by opening blow off valve and safety valve
allowing water to run out by gravity. Never drain boiler while
hot and not till ready to clean.
Describe a good method of washing a boiler.
Ans. Allow boiler to gradually cool to disintegrate the scale
and give time for most of it to settle on bottom. Remove man
340
Boiler Operation
hole and hand hole plates and play a strong stream of water be-
tween the tubes and around the shell.
·
What precaution should be taken?
Ans. Don't place a lighted candle or lamp inside the boiler
until after boiler is partly washed out.
Why?
Ans. If boiler compound or kerosene had been used in the
boiler, gases from these substances might cause an explosion.




E
Figs. 69 to 72.-Forms of chisel used in boiler cleaning.
What should be done after the boiler is washed out?
Ans. It should be entered for inspection and all braces and
stays should be carefully tested.
In looking for scale in horizontal boilers where should the
lamp be placed, and why?
Ans. Beneath the tubes so that any scale which may be
lodged between the tubes can be easily seen.
Boiler Operation
341
What should be done after closing the boiler?
Ans. Pour into the boiler several gallons of kerosene and allow
water to flow into the boiler very slowly, the slower the boiler
is filled, the more opportunity will the kerosene have to attack
the scale.
How is the interior of the boiler prepared for laying up?
Ans. After being cleaned it is thoroughly dried and must be
kept dry to prevent corrosion.
How may the interior be kept dry?
Ans. Some engineers make use only of the natural circulation
through upper and lower man and hand holes. Others place
flat vessels, filled with quicklime, for the absorption of all
moisture into the boiler, and then close it up tight.
How do you “boil out” a new boiler?
Ans. A new boiler may be cleaned by boiling out with a mix-
ture of soda ash and caustic soda. Fill the boiler with water to
about the middle line of the water glass and add 1 lb. of soda ash
and 1 lb. of caustic soda per 1000 lb. of water held within the
boiler. Dissolve the chemicals thoroughly before introducing
into the water. Close the boiler and start a light fire-sufficient
to carry 5 lb. pressure in the boiler. Continue boiling two or
three days. Then empty the boiler and wash it thoroughly with
fresh water.
What is the procedure after a week end shut down?
Ans. A light fire should be carried for about one hour. Only
in extreme emergency should steam be raised in less than one
half hour, even with water tube boilers.
342
Boiler Operation
Describe how to "cut in" a boiler.
Ans. When the steam pressure approaches the working pres-
sure and before cutting the boiler into service, blow the water
down to the proper level, if necessary. Before cutting in a boiler,
open and leave open until the boiler is on the line, all drains in
the connections between the boiler and the main header, espe-
cially the open drains between the two stop valves.
In general, in cutting in a boiler to a steam header already in service,
the steam line between the boiler and the header is usually warmed up
by backfeed through the drip line or by means of the bypass valve,
and the header valve then fully opened to allow the boiler to cut itself
in automatically with the non-return valve. In case a non-return valve
be not used, the boiler stop valve should, of course, be opened slowly
when the pressure in the boiler and the steam line are approximately
equal.
What is the procedure with two hand operated stop
valves?
Ans. With two hand operated stop valves, open slowly (to
avoid water hammer) to full opening, the stop valve nearer the
main header. When the pressure in the boiler is nearly equal
to the pressure in the main header, open slowly, to full opening,
the stop valve nearer the boiler.
What do you do in case of one hand operated stop valve
and one combined stop and check valve?
Ans. When the hand operated stop valve is nearer the main
header, open it slowly and preferably only a small amount at
first. When the pressure of the boiler is still 10 to 50 lb. below
the pressure in the header, slowly back off the valve stem of the
combined stop and check valve sufficiently from the check to
provide full opening of the check valve. In order to insure that
the check valve functions properly, always use it automatically
for cutting in and cutting out boilers, provided that the main
header is filled with steam at full pressure.
Boiler Operation
343
What is the procedure with one hand operated stop valve
and one automatic non-return check valve?
Ans. Open the hand operated stop valve slowly when the
pressure in the boiler is still 10 to 50 lb. below the pressure in the
main header.
How do you raise steam on a boiler not connected to a
common steam header?
Ans. In general, it would be more advisable to raise the steam
pressure on the whole steam line at the same time, all drips being
open.
What should be done after cutting in a boiler equipped
with non-return valves, with two independent outlets?
Ans. If the non-return valve be a combined stop and check
valve, operate the rising stem after the steam pressure in the
boiler has reached its working pressure, in order to ascertain
whether or not the valve has opened properly.
What should be done in case of foaming?
Ans. Close or partly close the steam outlet valve long enough
to determine the true level of the water in the water glass. If the
level of the water in the glass be sufficiently high, blow down.
some of the water in the boiler and feed in fresh water. Use sur-
face blow off if installed. Repeat the alternate blowing down and
feeding several times, and, if the foaming do not stop, bank
the fire and continue the alternate blowing down and feeding.
Determine positively the cause of foaming and adopt measures to
prevent its recurrence.
What precautions should be taken in operating blow off
cocks and valves?
344
Boiler Operation
Ans. They should be opened and closed carefully and slowly;
care should be exercised to make sure that when the valves or
cocks are closed, they are closed tightly.
How about the frequency of blowing down?
Ans. The volume and number of blow downs for a boiler
should be governed by the condition of the water in the boiler
and its effect on the quality of steam, and unless controlled by
analyses made at intervals, the minimum blow down shall be
once in 24 hours.
Where the feed water is high in solids, if the load be heavy or fluctuate
and wet steam be delivered, the blow downs must be regulated so that
concentration of the suspended matter and dissolved solids is kept
below the point at which priming or foaming begins or wet steam is
delivered.
What should be done when frequent blowing down does
not overcome wet steam?
Ans. The boiler carrying the highest concentrations, should
be dropped, cooled, emptied and refilled with fresh water. If
this do not correct the condition and more than one boiler be
in operation, follow the same procedure with the other units,
taking them down one at a time in order of the highest con-
centration.
Boiler Repairs
345
I
I
CHAPTER 21
Boiler Repairs
What should not be done in repairing boilers?
Ans. The work should not be entrusted to the local handy-
man or jack of all trades.

"W
o
. \\
I
Fig. 1.-Air leak detector cone and method of using. In testing, by pressing
the cone up against the setting and holding a candle in front of the small hole,
any air leak in the brick setting will draw in the candle flame.
་་་་
346
Boiler Repairs
What should be done before making repairs?
Ans. If boiler be insured first notify the insurance company
to send an inspector who will recommend how the repairs should
be made.
What breakdowns are most likely to occur in a boiler?
Ans. 1, Cracks; 2, bulges, 3, leaky or split tubes; 4, stay bolts
or braces; 5, defective fittings.

Fig. 2.-Method of removing a cylindrical furnace from its position in the boiler.
What is the cause of cracks?
Ans. Original defects of the material or faulty methods in
manufacture.
Where do cracks usually occur?
Ans. They may show around rivet holes, at flanged corners
or between tube openings.
What is grooving?
Ans. Surface cracking of boiler plates.
Boiler Repairs
347
P
What causes grooving?
Ans. Expansion and contraction of parts too rigidly con-
nected.
||||||||||||||||||||||
How should cracks be repaired?
Ans. If possible the cracks should be drilled off at the ends
by small holes, which will prevent further extension, and patches
put over them, either on the inside or on the outside.
How may a bulge be forced back into place?
Ans. If the plate be not burned, and not drawn thin, heat
LEAK

|||||||||||
BOILER TUBE
SOFT PINE PLUG
Fig. 3.-Easy method of repairing a leaky boiler tube. A plug, shaped as shawn
pushed into the flue until it reaches the point of leakage, where the escaping
steam and water cause it to swell, thus stopping the leak.
it red hot by rigging up a gas furnace under the bulge and drive
it up into its original position.
What should be done if the plate were burned?
Ans. The burned part must be cut out and a patch put on.
What may be resorted to if the bulged plate be not in
348
Boiler Repairs
convenient reach from rigid parts of the boiler for stay
bolt connection?
Ans. Girders.
How should bulged circular furnaces be treated?
Ans. If not altogether collapsed, they may be put in such

M
Lai
E
DODONE
DI
W
C
TUBE
x
D3
Figs. 4 and 5.-Rubber tube stopper. As shown, A, is the threaded end of the
iron rod; E, the nut; D1, D2, D3, D4 washers; D and D rubber discs; C, iron
gas pipe; M. holes in washers, open at W.
PLUGS
メー
​D
D2
D
04

NUT
NUT
Fig. 6.—Emergency device for stopping a leaky boiler flue. An iron rod, E, hav-
ing a thread at both ends, is fitted with a nut and washer, is then put on;
then a rubber plug; another washer and a length of gas pipe against the
second washer. The opposite end of the rod is similarly fitted, after which the
act of screwing up the nuts causes the rubber plugs to bulge, filling the tube.
Boiler Repairs
349
condition that they will safely carry a reduced steam pressure,
by closely spaced circular rings of angle or bar iron, fitted in
halves.
How do you make a temporary repair to a split tube?
Ans. By plugging.
How is a tube stopper applied?
Ans. The fires must be drawn and boiler cooled so that a man
can enter the combustion chamber to insert the plug.
"
M...
m
""
Fig. 7.-Ripper or plough chisel. It consists of a flat chisel about 1½ inches
wide and 5/16 inch thick. It is made convex, or crescent shape, on the end and is
ground square or blunt similar to a caulking tool.
be, dallim
MED AS A FELLA
|11:
A
:


delt
Gla

יומי,
Figs. 8 and 9.-Beading tool and long wedge used to fold tubes.
How does a stopper stop a leak?
Ans. When pushed in the tube to the point of leakage the
escaping steam and water cause the plug to swell, thus stopping
the leak.
350
Boiler Repairs
What causes the upper ends of tubes of through tube
vertical boilers to leak?
Ans. Greenhorn handling, such as forcing, too low water
level, and getting up steam without entirely filling the boiler.

BLUNT TOOL FOR
DRIVING OR TEARING
OF Y SHAPED PIECE

38" BLADE
FOLDED ENDS
HEADER SECTION
NIPPLE CUT HERE
MUD DRUM SEAT
RIPPER FOR CUTTING
NIPPLE IN HALF
Fig. 10.-Method of replacing nipples in water tube boilers, B. and W. type.

Fig. 11.-Cutting and folding tube end to permit removal.
Boiler Repairs
351
Where does grooving and cracking of tubes usually occur
and why?
Ans. In the lower tubes at the combustion chamber end,
caused by pumping comparatively cold water into the boiler in
such a way that it comes in contact with the hot tubes.
с
こ
​о
с

ооо
о
о
ОО С
А
о
-B
ооо
оо
Fig. 12.-A convenient method of repairing a cracked tube sheet. A patch,
such as is shown at base of the cut, is shaped to fit neatly over the crack and
between the tube ends. After smearing both surfaces with red lead, it is secured
in place by tap bolts.

ос
000
Fig. 13.-Extended "spectacle piece," or patch covering tube sheet cracks be-
tween three adjacent tubes. Such cracks are usually caused by allowing scale
to collect on the sheet inside the boiler, or by frequent opening of the fire doors,
when boiler has a heavy fire.
352
Boiler Repairs
I
In retubing, describe how to remove a tube.
Ans. Cut a long slot in tube from front and extending back
about 8 ins. to contract the tube. Cut back end loose and pull
out tube.
What is a boiler patch?
Ans. A small piece of metal used to cover and strengthen a
weak spot.




1
5
The
2
6
7
Name two kinds of boiler patches.
Ans. Soft and hard.
3
4
8




Figs. 14 to 21.—Caulking. Opinions differ as to the proper shape of the caulking
tool and proper shape of the plate edges to obtain the best results in caulking
seams. 1, shows the shape of the caulking tool and proper way to hold the tool
when the edge of the plate is square; 2, result of caulking a seam in this manner,
giving fair results; 3, shows same tool improperly held when the edge of the
plate is bevelled; 4, shows the bad result of caulking a seam in this manner;
5, shows the proper way to hold this tool against the bevelled edge of the plate;
6, result obtained after caulking-although the tool is held properly the result
is not good; 7, shows a better method, or proper way to hold a round nose
caulking tool against a square edged plate; 8, result after caulking. In caulking
with this shape of tool, care must be taken that it is not too small, as it will then
act as a wedge and separate the plates. Care must also be used in grinding
the flat nosed tool; if the tool has too much bevel, the lower edge will bite
into the lower plate.
Boiler Repairs
353
What is the difference between a soft and a hard patch?
Ans. A soft patch is a covering over a leak or defect which is
fastened with bolts, as distinguished from a hard patch which is
riveted.*
How is a soft patch put on so that no caulking is neces-
sary?
Ans. It may be fitted as closely as possible by heating and
forging. The holes may then be drilled and those in the shell
beneath the patch tapped or drilled large and through bolts
used.
NOTE.-In ordering new tubes, the length should be accurately measured
on a strip of wood or a piece of pipe passed through the old ones, allowing from
18 to 316 inch on each end for beading over. If more than one boiler is to be re-
tubed, measure each one, as it will probably be found that there is a difference
although they are all supposed to be the same. The ends of the new tubes are
supposed to have been annealed before delivery, but it is doubtful if this has been
done, so it is a good plan to heat them to a dull red and bury them in lime, allow-
ing them to cool very slowly. This will make them much easier to expand and bead,
and will reduce the liability of their cracking during these operations.
NOTE.-Rolling tubes too much thins the metal and hardens it, resulting
in cracking in rerolling.
NOTE.-In water tube boilers, the process of removing tubes is about the
same as in tubular boilers, but the tubes are taken out with less difficulty. Since
the ends are not so easily reached a ripper is almost a necessity for splitting the
tubes. The ends can then be folded in by the means of the long slender wedge
shown in fig. 9 A good plan is to cut two deep notches in the end of the tube,
about an inch apart and then with a bar force the part of the projecting end of
the tube between these notches, away from the tube sheet or header, using the
edge of the handhole as a fulcrum for the bar. This produces a slight space between
the tube and the tube sheet, into which the wedge may be started, and when it is
driven home there is plenty of space left, so there is no danger of scoring the tube
sheet with a ripper. If the defective tube be in the lower row, as is usually the
case, its removal may be facilitated by cutting the tube into two or three sections
with a three wheel pipe cutter, and removing the ends from the tube sheets from
inside the furnace From this point the operation is the same as that described for
the horizontal tubular boiler, except that they are flared by one of the methods
described in previous paragraphs.
*NOTE.—The difference between a soft and a hard patch is a favorite question
with examiners, hence the applicant for license should understand this thoroughly.
354
Boiler Repairs
Describe how to make a caulking tool.
Ans. Select a very heavy cold chisel (one made from 8 in.
to 1 in. octagon steel is the best) and forge or grind the end off
until it is about 1/4 in. thick. Then round the end of the tool until
it is a perfect half circle 1/4 in. in diameter and at least 1 in. wide.
How is caulking done?
Ans. Place this tool against the slope of a rivet about 6 in.
from the shell plate, and strike the tool with a hammer, keeping
the tool inclined more or less parallel with the shell of the
boiler.
Boiler Calculations
355
CHAPTER 22
Boiler Calculations
What is one boiler horse power?
Ans. The evaporation of 30 lbs. of water from an initial
temperature of 100° Fahr. to steam at 70 lbs. gauge pressure,
which is equivalent to 34.5 lbs. of water evaporated per hour
from a feed water temperature of 212° into dry steam at the
same temperature.
What is the abbreviation for the expression: "from a
feed water temperature of 212° into dry steam at the same
temperature."
Ans. It is abbreviated to "from and at 212°".
If a boiler evaporate 600 lbs. of steam at 105 lbs. pressure
per
hour from feed water at 100° Fahr. what is the equiva-
lent evaporation "from and at 212°”.
Ans. The factor of evaporation from table page 56=1.158.
Equivalent evaporation = 600 × 1.158 694.8 lbs. "from and
at 212° Fahr."
If the rate of evaporation be given as 8 lbs. of steam per
pound of coal how much coal is required to evaporate
600 lbs. of steam under the conditions just given?
356
Boiler Calculations
Ans. Total coal per hour total evaporation per hour X
factor of evaporation rate of evaporation. Substituting:
Total coal per hour
= 86.85 lbs.
600 X 1.158
8
Upon what does the size of grate depend?
Ans. It depends upon the rate of combustion and amount of
coal to be burned per hour.
What is an ordinary rate of combustion in stationary
practice?
Ans. About 12 lbs. of coal per sq. ft. of grate per hour.
=
If the total coal burned per hour be 86.85 lbs. and the
combustion rate be 12 lbs. what is the required area of
grate?
86.85 ÷ 12 - 7.24 sq. ft.
Ans. Area of grate
144 1042.6 sq. ins.
7.24 X
How do you find the diameter of the grate after finding
the area?
Ans. Look it up in a table of "Properties of Circles" taking
the nearest value larger than that corresponding to the given
area.
Thus from table page 358 nearest area larger than, 1042.6 sq. in. is
1046.3 ins. corresponding to 36½ ins. diameter.
Would a boiler ordinarily be built with such a dimension
for a grate and why?
Ans. No. Standard dimensions such as 36 ins. (rather than
36½ ins.) are used where the difference is not too great.
Boiler Calculations
357
Why not use the exact dimension as calculated?
Ans. A boiler is far from being "a hard boiled egg" like a
gas engine. In other words the range of output of a boiler is
very great, whereas a gas engine has one maximum rating
above which further forcing is not practical owing to its inherent
defects.
Suppose you didn't have a table giving the "Properties
of Circles" how would you find the diameter of grate
corresponding to a given area?
Ans. To find the diameter of a circle having a given area:
RULE. Divide the area by .7854 and extract the square root.
For the area just given (1042.6 sq. ins.) this would be substituting:
1042.6
Diameter of grate 1
V = 36.4 ins., say 36 ins.
.7854
area
.7854
Why is the decimal .7854 used in finding the area or
diameter of a circle?
Ans. It is a ratio which gives the difference in area of a circle
and a circumscribed square.
What other way is .7854 expressed?
Ans. As 14 T, that is 4 X 3.1416 or .7854.
What is 3.1416?
Ans. A ratio which expresses the relation between the length
of the diameter and length of the circumference of a circle.
That is, the circumference is 3.1416 times longer than the diameter.
Thus, for a circle 4 ins. in diameter circumference =3.1416×4=12.566
ins.
358
Boiler Calculations
Diam. Circum. Area
16
0.0491 0.0002
0.0982 0.0008
0.1964 0.0031
0.2945 0.0059
0.3927 0.0123
0.4909 0.0192
0.5890
0.6872
/6
11
1
0.9817
1.0799
0.7854 0.0491
0.8836
0.0621
0.0767
0.0928
0.1105
0.1296
0.1503
0.1726
3/8
1.1781
13 1.2763
16 1.3745
151.4726
1/2 1.5708
11.6690
16 1.7672
11.8653
5/8 1.9635
12.0617
116 2.1598
32.2580
Circumferences and Areas of Circles
Diam. Circum. Area
Diam. Circum. Area
Diam. Circum. Area
9.4248
8
25.1327
50.265
7.0686
7.3662
9.6211
25.5254
51.849
9.8175 7.6699
50.2655 201.06
50.6582 204.22
25.9181 53.456
51.0509 207.39
26.3108 55.088 3/8 51.4436 210.60
26.7035 56.745 12 51.8363
10.0138
7.9798
10.2102
8.2958
213.82
10.4065
8.6179
217.08
10.6029 8.9462
52.2290
52.6217
53.0144 223.65
220.35
10.7992
9.2806
27.0962 58.426 5/8
27.4889 60.132
27.8816 61.862
28.2743 63.617 17
28.6670 65.397
29.0597 67.201
29.4524 69.029
29.8451 70.882
72.760
30.2378
30.6305
74.662
31.0232 76.589

/b
7/16
$16
3/8
16 4.5160
0.4418
0.4794
0.5185
1/ 2.3562
35 2.4544
12.5525
172.6507 0.5591
/8 2.7489 0.6013
292 2.8471 0.6450
156 2.9452 0.6903
31 3.0434 0.7371
12
4.7124
6
4.9087
5/8
5.1051
116 5.3014
3/ 5.4978
136 5.6941
3.1416
0.7854
0.8866
3.3379
0.9940
3.5343
3.7306
1.1075
3.9270
1.2272
4.1233
1.3530
4.3197 1.4849
1.6230
$16
0.0276 %
0.0376 16
3
4
0.1964
0.2217
1/6
0.2485 18
0.2769
0.3068
0.3382
0.3712
0.4057
1.9175
2.0739
2.2365
2.4053
2.5802
//% 5.8905 2.7612
156 6.0868 2.9483
5/R 8.2467
118.4430
2 8.6394
13% 8.8357
1/2 9.0321
15% 9.2284
16
1/8
$16
X
7.0686 3.9761
7.2649 4.2000
7.4613 4.4301
7.6576 4.6664
6.2832 3.1416 6
10.9956
9.6211
11.1919
1/2
916
9.9678
5/8 11.3883 10.321
1611.5846 | 10.680
411.7810 | 11.045
136 11.9773 11.416
12.1737 | 11.793
12.1737
12.3700 | 12.177
%
156
4
5/16
12.5664 12.566
12.7627 | 12.962
12.9591 13.364
13.1554
13.3518
13.772
14.185
13.5481 14.607
13.7445 15.033
13.9408 15.466
K6
1/4 14.1372
9/16
14.3335
5/2 14.5299
1114.7262
17.721
14.9226
156 15.1189 18.190
15.3153 | 18.665
15 15.5116 19.147
5 15.7080
116 15.9043
18 16.1007
$16
1
3/16
1/8
7.8540 4.9087 7
8.0503 5.1572
5.4119
5.6727
5.9396
6.2126
6.4918
6.7771
16
1.7671 12
17,2788 23.758
17.4751 24.301
16
$8 17.6715 24.850
16 17.8678 25.406
18.0642 25.967
136 18.2605 26.535
7/8
% 18.4569 27.100
156 18.6532 27.688
15.904
16.349
16.800
17.257
2
18.849628.274
116 6.4795 3.3410
Y 19.2423 29.465
1/8 6.6759 3.5466 ¼ 19.6350 30.680
16
6.8722 3:7583
20.0277 31.919
1
20.4204 33.183
20.8131 34.472
21.2058 35.785
21.5984 37 122
16.2970 21 135
16.4934 21.648
16.6897 22.166
16.8861 22.691
17.0824 23.221
19.685 12
20.129
20.629
21.9911 38.485
22.3838 39.871
22.7765 41.282
23.1692-42.718
9
23.5619
44.179
45.664
23.9546
24.3473 47.173
24.740048.707
10
11
13
14
1/8
1½
\00\\\00\~\~\{~\∞
\~\&\&\\\\_~0\\_/\_\ =
1/8
∞\A\
\\
7/8
बोलोकालोकोलोल
1/2
[∞∞\\\∞∞
1/8
31.4159
31.8086
32.2013
//%
78.540
80.516
40.8407 132.73
1/8 41.2334 135.30
41.6261 137.89
42.0188 140.50
42.4115 143.14
42.8042 145.80
43.1969 148.49
43.5896 151.20
37.6991 113.10
38.0918 115.47
38.4845 117 86
38.8772
120.28
39.2699 122.72
39.6626 125.19
40.0553 127.68
40.4480 130.19
82.516
32.5940 84.541
32.9867
86.590
33.3794
88.664
90.763
33.7721
34.1648
92.886
3
34.5575 95.033 19
34.9502 97.205
35.3429 99.402
35.7356 101.62
36.1283 103.87
36.5210 106.14
36.9137 108.43
37.3064 110.75
43.9823 153.94
44.3750 156.70
44.7677 159.48
45.1604 162.30
45.5531 165.13
45.9458 167.99
16
1/2
46.3385 170.87
46.7312 173.78
18
20
1/8
1/4
21
1/8
56.5487 254.47
56.9414 258.02
1/4 57.3341 261.59
57.7268 265.18
58.1195 268.80
58.5122 272.45
58.9049 276.12
59.2976 279.81
32
222
15
47.1239 176.71 23
18 47.5166 179.67
1
47.9093 182.65
48.3020 185.66
48.6947 188.69
49.0874 191.75
49.4801 194.83
49.8728
197.93
∞
\C\~\&\\
1001~3~0\\\\\
53.4071 226.98
53.7998 230.33
54.1925 233.71
54.5852 237.10
54.9779 240.53
55.3706 243.98
55.7633 247.45
56.1560 250.95
346.36
350.50
65.9734
1/8 66.3661
66.7588
67 1515
67.5442
¼
354.66
358.84
363.05
67.9369
68.3296
367.28
371.54
68.7223 375.83
48
1/
K
59.6903 283.53
60.0830 287.27
60.4757
60.8684
61.2611
291.04.
294.83
298.65
61.6538 302.49
62.0465 306.35
62.4392
310.24
62.8319 314.16
63.2246 318.10
63.6173
64.0100
322 06
64.4026
326.05
330.06
64.7953 334.10
65.1880 338.16
65.5807
342.25
69.1150 380.13
69.5077 384.46
69.9004 388.82
70.2931
393.20
70.6858 397.61
71.0785 402.04
71.4712 406.49
71.8639 410.97
72.2566
415.48
72.6493 420.00
73.0420 424.56
73.4347 429.13
73.8274 433.74
74.2201 438.36
74.6128 443.01
75.0055 447.69
Boiler Calculations
359
24
1/2
Diam. Circum.
75.3982 452.39 32
75.7909 457.11
76.1836 461.86
76.5763 466.64
76.9690 471.44
77.3617 476.26
77.7544 481.11
78.1471 485.98
25
26
27
29
30
3/8
28
VA
BABA\n\~\~\
\\\\\\\\\\\∞
31
»\\\\\\»\@\^\\
\&\\_/\_~*
\~\0\0\
\\M\N\
1\0\0\0
\&\~~\~ \<\∞
\\\\\\\\\\\\\,00
लोलोलोल
∞\A\&\ 65\20\\A\ N
78 87.5719 610.27
• co\A\ co\% 85\\,40\
\0\~\
•\20\GEN00
38
Circumferences and Areas of Circles—Continued
Area Diam. Circum. Area
Area Diam. Circum. Area Diam. Circum.
125.664 1256.6 48
1/8 126.056 1264.5
1
126.449 1272.4
126.842 1280.3
127.235 1288.2
127.627 1296.2
128.020 1304.2
128.413 1312.2
150.796 1809.6
1/8 151.189 1819.0
V 151.582 1828.5
151.975
1837.9
1847.5
1½ 152.367
152.760 1857.0
153.153 1866.5
153.545 1876.1

\__#__#\&\~\~\-\~
[G0\ {^\ co \A\20\
81.6814 530.93
82.0741 536.05
82.4668 541.19
82.8595 546.35
83.2522 551.55
83.6449 556.76
84.0376 562.00
84.4303 567.27
78.5398 490.87 33
78.9325 495.79 1/8
79.3252 500.74
79.7179 505.71
80.1106 510.71
80.5033 515.72
80.8960 520.77
81.2887
525.84
84.8230 572.56 35
85.2157 577.87
85.6084 583.21
86.0011 588.57
86.3938 593.96
86.7865
599.37
87.1792 604.81
91.106
91.499
91.892
92.284
92.677
93.070
643.55
649.18
654.84
345
87.965 615.75 36
88.357
1/2
621.26
88.750 626.80
89.143
632.36
637.94
89.535
89.928
90.321
90.713
660.52
666.23
671.96
677.71
683.49
689.30
94.248
706.86 38
94.640 712.70
718.69
95.033
95.426
724.64
½ 95.819
730.62
96.211 736.62
96.604
742.64
96.997 748.69
93.462 695.13
700.98
93.855
37
100.531 804.25 40
100.924 810.54
101.316 816.86
101.709 823.21
102.102. 829.58
102.494 835.97
102.887 842.39
103.280 848.83
103.673 855.30 41
104.065 861.79
104.458 868.31
104.851 874.85
105.243 881.41
8 105.636 .888.00
106.029 894.62
1/2
3/
106.421
901.26
97.389
754.77 39
760.87
97.782
98.175
98.567
766.99
773.14
779.31
98.960
99.353 785.51
99.746 791.73
100.138
797.98
8
106.814
907.92
1/8 107.207 914.61
¼ 107.600
3/8 107.992
921.32
928.06
108.385 934.82
108.778 941.61
109.170
948.42
955.25
109.563
1/2
.00\\\
\~\&\\\
\\00
113.097
113.490
113.883 1032.1
114.275 1039.2
114.668 1046.3
115.061 1053.5
115.454 1060.7
115.846 1068.0
1/½
¼
7%
42 131.947
1385.4
1393.7
1%
132.340
132.732
1402.0
133.125 1410.3
.133.518
1418.6
133.910
134.303
134.696
~~\
109.956
1/4
962.11 43
110.348 969.00 18
110.741 975.91
111.134 .982.84
111.527 989.80
111.919 996.87
112.312 1003.8
112.705 1010.8
16
1017.9 44
1025.0
%
116.239 1075.2 45
116.632 1082.5
117.024 1089.8
117.417 1097.1
117.810 1104.5
118.202 1111.8
118.596 1119.2
118.988 1126.7
122.522 1194.6 47
1/8 122.915 1202.3
123.308 1210.0
1
123.700 1217.7
124.093 1225.4
124.486 1233.2
124.878 1241.0
125.271
1248.8
128.805 1320.3 49 153.938 1885.7
129.198 1328.3 Y 154.331 1895.4
129.591 1336.4 1/4 154.723 1905.0
129.983 1344.5
155.116 1914.7
130.376 1352.7
155.509 1924.4
130.769 1360.8
155.902 1934.2
131.161 1369.0
156.294 1943.9
131.554 1377.2
156.687
1953.7
1427.0
1435.4
1443.8
1452.2 51
135.088
135.481
1460.7
135.874
1469.1
136.267
1477.6
136.659 1486.2
137.052 1494.7
137.445 1503.3
137.837 1511.9
141.372
141.764 1599.3
¼ 142.157 1608.2
3/2 142.550 1617.0
1/2 142.942 1626.0
143.335 1634.9
143.728 1643.9
144.121 1652.9
138.230 1520.5
52
¼
1/2 138.623 1529.2 1/8
139.015
Y
1537.9
139.408 1546.6
139.801 1555.3
140.194 1564.0
140.586
1572.8
140.979
1581.6
1983.2
50 157.080
1/8 157.472
X 157.865
158.258 1993.1
158.650 2003.0
159.043 2012.9
159.436 2022.8
159.829 2032.8
1590.4 53
119.381 1134.1 46
119.773 1141.0 1/3 144.906 1670.9
120.166 1149.1
120.559 1156.6
120.951 1164.2
121.344 1171.7
121.737 1179.3
122.129 1186.9
1/1 145.299 1680.0
3/2 145.691 1689.1
16 146.084 1698.2
146.477 1707.4.
146.869 1716.5
147.262 1725.7
3/
И
12
1790.8
1800.1
1½
~~X
¾
1/8
1/8
144.513 1661.9 54
1/8
8/
7/8
1/2
147.655 1734.9 55
148.048 1744.2
148.440 1753.5
148.833 1762.7
149.226 1772.1
149.618 1781.4
150.011
150.404
AM
[\+\®
1963 5
1973.3
2042.8
2052.8
160.221
160.614
161.007 2062.9
161.399
2073.0
161.792
2083.1
162.185
2093.2
162.577 2103.3
162.970 2113.5
163.363
2123.7
163.756
2133.9
164.148
2144.2
164.541
2154.5
164.934 2164.8
165.326 2175.1
165.719 2185.4
166.112
2195.8
166.504
2206.2
166.897
2216.6
167.290
2227.0
167.683
2237.5
168.075 2248.0
168.468
168.861
169.253
169.646
2290.2
170.039 2300.8
170.431 2311.5
170.824 2322.1
2332.8
171.217
171.609
2343.5
2354.3
3/4 172.002
172.395 2365.0
2258.5
2269.1
2279.6
172.788 2375.8
173.180 2386.6
173.573 2397.5
173.966 2408.3
174.358 2419.2
174.751 2430.1
175.144
2441.1
175.536 2452.0
360
Boiler Calculations
For a vertical boiler how is the diameter determined to
accommodate a grate of given diameter?
Ans. Space must be allowed for: 1, thickness of metal of
furnace sheet; and 2, thickness of water leg.
These allowances are multiplied by 2, since allowance must be made
for both sides of the furnace.
Expressed as a formula:
Inside diameter of shell =diam. of grate+2× (thickness furnace sheet +
width of water leg).
For a 36 in. grate, 1½ in. water leg and furnace wall ½ in. thick;
inside diameter of shell =36+2 (½+1½)=36+1+3=40 ins.
If a boiler have a grate area of 7.07 sq. ft. and the ratio
of heating surface÷grate area be 25, how much heating
surface must be provided?
Ans. 7.07X25-176.8, say 177 sq. ft.
Of what does this heating surface consist considering a
vertical tubular boiler?
Ans. 1, Furnace heating surface, and 2, tubular heating
surface.
Suppose the furnace be 36 ins. in diameter and 18 ins.
high, what is its heating surface?
Ans. Reducing dimension to feet: 36 ins. =36÷12-3 ft.;
18 ins. =18÷12=1½ ft.
From which area of furnace heating surface = (3.1416×3) X
112=9.43 X1½-14.2, say 14 sq. ft.
Boiler Calculations
361
External
Diameter
1 000
1 250
1 500
1 750
External Circumference.
diameter
inches
inches
2.000
2 250
2.500
2 750
ins.
ins.
ins. B.W.G.
13
13
1
.810 .095
144 1.060
1.060.095
11/22 1.310 .095 13
1341.560
1.560.095 13
2 1.810 .095 13
2½ 2.282 .109
3 2.782.109
3.260 .120
4 3.732.134
4½ 4.232 .134
4.701.148
5.670.165
12
12
3%
5
6
3.000
3 250
3.500
4.000
4.500
5.000
5.500
6.000
6.500
7 000
7 500
8 000
Properties of Standard Lap Welded Boiler Tubes

Internal
Diameter
8.500
9 000
9 500
10 000
3 1416
3 9270
4 7124
5 4978
6 2832
7 0686
7 8540
8 6394
9.4248
10.210
10.996
12.566
14 137
15 708
17.279
18 850
20.420
21.991
23.562
25.133
Standard
Thickness
26.704
28.274
29.845
31 416
2000-∞
Surface per lineal foot
37 699
47.124
56.549
65.973
Square inches Square feet
75.398
84.823
94.248
EXTERNAL PROPERTIES
Circumference, Surface, Area and Volume
103 67
113 10
122 52
ins.
ins.
sq. ins. sq. ins.
2.545 3.142
.515
.882
.785
1.227
1.767
1.348
1.911
1.679
1.932
2.783
3.330 3.927
4.115 4.712
4.901 5.498
2.405 2.448 2.183
5.686 6.283 2.573 3.142 | 2.110 |.1.910
7.169 7.854 4.090 | 4.909 1.674 1.528
8.740 9.425 6.079 7.069 1.373 1.273
11 10.242 10.996 8.347 | 9.621 1.172 1.091
10 11.724 12.566 10.939 12.566 1.024 .995
10 13.295 14.137 14.066 15.904 .903
9 14.778 15.708 17.379 19.635
8 17.813 18.850 25.250 28.274
3.365
4.331
5.532
.849
6.248
.764
7.669
.812
.074
.637 10.282
131 95
150 80
169.65
188.50
207.35
226 19
245.04
263.89
Internal
Circumference
282.74
301.59
320.44
339.29
358.14
376.99
2618
.3272
3927
4581
5236
5890
6545
7199
7854
8508
9163
1.0472
1.1781
1.3090
1.4399
1.5708
External
Circumference
1.7017
1.8326
1.9635
2.0944
2.2253
2.3562
2.4871
.2.6180
Lineal feet
of tube
per square foot
of surface
3.8197
3.0558
2.5465
2.1827
1.9099
1.6977
1 5279
1 3890
1.2732
1.1753
1.0913
.9549
.8488
7639
6945
.6366
5876
.5457
.5093
4775
Internal
Area
4494
4244
4021
3820
Transverse area
square inches
.7854
1.2272
1.7671
2.4053
3.1416
3.9761
4.9087
5.9396
External
Area
7.0686
8.2958
9.6211
12.566
15.904
19.635
23.758
28.274
33.183
38.485
44.179
50.265
56.745
63.617
70.882
78.540
Length of Tube
per Sq. Ft. of
Inside Surface
£t. ft.
Latyn
Cubic inches
lbs.
4.479 3.820 .90
3.604 3.056 1.15
2.916 2.547 1.40
9.4248
Volume or displacement per lineal foot
14.726
21.206
28.863
37.699
47.713
58.905
71.275
84.823
99.549
Length of Tube
per Sq. Ft. of
Outside Surface
115.45
150.80.
190.85
235.62
285.10
339.29
398.20
461.81
530.14
603.19
680.94
763.41
850.59
942.48
Cubic feet.
also area in
square feet
.0055
.0085
.0123
0167
.0218
.0276
.0341
.0412
.0491
.0576
.0668
.0873
.1104
.1364
.1650
.1963
Weight per
Lineal Foot

.2304
.2673
.3068
.3491
.3941
.4418
.4922
.5454
United States
gallons
.0408
.0637
.0918
.1249
..1632
.2065
.2550
.3085
.3672
4309
1998
.6528
.8262
1.0200
1.2342
1.4688
1.7238
1.9992
-2.2950
2.6112
2.9478
3.3048
3.6822
4.0800
362
Boiler Calculations
Considering the same boiler having 177 sq. ft. of heating
surface, deducting the furnace heating surface, how
much tubular heating surface must be provided?
Ans. 177-14=163 sq. ft.
What governs the diameter and length of tubes?
Ans. The type of boiler and service requirements.
For an ordinary vertical shell boiler having a 36 in. lower
tube sheet which will easily accommodate 91, 2 inch
tubes, how would you find the length of tubes giving
163 sq. ft. of tubular heating surface?
-
Ans. In the table of "Properties of Boiler Tubes" on page
361 find for a 2 in. tube, length of tube per sq. ft. of inside
surface is 2.11 ft. Hence total length of tubes = 163 X2.11
343.9, say 344 ft. For 91 tubes length of each tube = 344÷91
3.78 ft. or 3.78×12=45.4 ins.
=
Would such a tube dimension as 45.4 ins. be used in
boiler construction?
Ans. No.
Why?
Ans. The dimension of tube length would be such that the
tubes could be cut to that length without wastage, that is,
stock lengths would be selected by the designer.
What length would be used in place of 45 ins.?
Ans. Say 42 ins. or 48 ins. increasing or decreasing the
number of tubes respectively to keep the tubular heating
surface the same.
Boiler Calculations
363
Suppose you didn't have a table of "Properties of Boiler
Tubes" available, how would you figure the tubular
heating surface?
Ans. RULE: Multiply number of tubes by inside circumference
by length and divide by 144. Expressed as a formula:
Tubular area in sq. ft. (Number of tubes Xinside
circumference Xlength) ÷ 144.
-
What is the internal heating surface of 91 two inch
tubes 48 ins. long?
Ans. From table, page 361, inside diameter of a 2 in. tube=
91X(1.81 X3.1416) ×48
=172.5 sq. ft.
144
1.81" Applying rule area =
The following examples will illustrate the great convenience
of the table.
Example. - How many sq. ft. of inside heating surface in 40, four
inch tubes, each 16 feet long?
From the table, the length of a 4 in. tube per sq. ft. of inside surafce is
1.024 ft., hence
40 X 16
1.024
=
total heating surface
625 sq. ft.
Example. - How many feet of one inch tube is required for 140 sq. ft.
of inside heating surface, and what is the weight?
From the table the length of 1 in. tube per sq. ft. of inside surface is
4.479 ft., hence
amount of 1 in. tube required 140 X4.479
627 ft.
From the table 1 in. tube weighs .9 lb., per lineal foot hence,
weight of 627 ft. of 1 in. tube 627 X.9 = 564 lbs.
-
****c
What comprises the heating surface of a horizontal
return tubular boiler?
Ans. 1, The shell surface; 2, the tubular surface; and 3, net
area of tube sheets.
364
Boiler Calculations
What part of the sheet surface is taken and how much?
Ans. That part exposed to the hot gases of combustion; in
amount about 200° of circumference.
HEATING SURFACE CALCULATION
of
Horizontal Return Tubular Boiler
The method of calculating the heating surface is here given
in tabulated form, as follows:
Rules: Take the dimensions in inches:
Shell: Multiply length by fraction of circumference in contact with hot
gases.
Tubes: Multiply the sum of the inside circumferences of all of the
tubes by their common length.
Tube Sheets: Multiply twice the diameter squared by .7854 and
subtract twice the sum of the internal areas of all the tubes (similarly
obtained).
Total Heating Surface: Divide the sum of the several areas just
obtained by 144.
What should be noted in finding the heating surface of
the tubes?
Ans. The sizes of boiler tubes as given are the outside diam-
eters, whereas in calculating the heating surface of horizontal
boilers the inside diameter is taken to determine the surface
exposed to the fire and hot gases.
Boiler Calculations
365
Example. What is the heating surface of a horizontal return
tubular boiler 54 ins, in diameter, 16 ft. long and having 40 tubes
each 4 ins. in diameter?
A. Shell
B. Tubes
area = 54 X3.1416 X
NOTE.-3.1416 or π is the number which multiplied by the
diameter of a circle gives the circumference. 200÷360 is
the fractional part of the shell in contact with the hot
gases. (16 X12) is length of shell in inches.
200
360
Sq. ins.
×(16×12) = 18,096
area = 40X(3.732 ×3.1416) ×(16×12) = 90,040
NOTE.-40 is the number of tubes. 3.732 is the inside
diameter of a standard 4 in. tube obtained from the table
on page 361. (3.732 ×3.1416) is the inside circumference.
(16 X12) is the length of each tube in inches.
C. Tube Sheets
gross area of sheets =2X542X.7854
= 4,580
twice area of tubes =2×40 ×3.732²×.7854 - 875
net area of sheets = Xgross area sheets
-twice area tubes
X4,580-875
total heating surface of boiler in sq. ins.
144
NOTE.-Gross area of sheets: This is the area not in-
cluding that cut away by holes for tubes. 54 = diameter
boiler; .7854 is that fraction which multiplied by the
diameter squared gives the gross area of one sheet. Area
of tubes: This means the cross sectional area. 40 = number
of tubes; 3.732 inside diameter of a tube, the inside
diameter being taken because the thickness of each tube
is here considered as forming a part of the tube sheet, as
it is regarded as sheet heating surface. Net area of tubes:
The factor 2% is introduced because ordinarily only 2% of
the sheet area is exposed to the hot gases this is an
approximation and to be exact the exposed portion of
sheet area must be measured. The factor 2 is used in both
equations because there are two sheets.
=
D. Total Heating Surafce
total area
A+B+C_18,096 +90,040+2,178
144
:
2,178
110,314
=766 sq. ft.
366
Boiler Calculations
How do you find the inside diameter of a boiler tube?
Ans. From a table giving "Properties of Standard Boiler
Tubes." (See page 361.)
These diameters have a nasty decimal fraction and it is better to
look up cross sectional areas in the table than to calculate same as the
example just given will indicate.
How do you calculate the tubular heating surface of a
water tube boiler?
Ans. By basing the calculations on the outside area of the
tubes instead of the inside area.
What should be noted about tube and pipe diameters?
Ans. A tube diameter is given as the actual outside diameter
whereas a pipe diameter is given as the nominal diameter which
is considerably different from the listed diameter.
For instance a wrought pipe listed as ½ in. pipe has an actual out-
side diameter of .84 in. and an actual inside diameter of .622 ins.
How many linear feet of 3/4 wrought pipe is required for
163 ft. of heating surface?
Ans. From the table of "Properties of Wrought Pipe", page
367, length of 3/4 in. pipe per sq. ft. of external surface = 3.637 ft.
hence length of 3/4 in. pipe for 163 sq. ft. of heating surface
= 163×3.637 =592.8, say 593 ft.
How much heating surface is ordinarily allowed per
boiler horse power?
Ans. 12 sq. ft.
On what is the horse power old rating based for a through
tube vertical boiler?
Ans. On the outside diameter and full length of the tubes.
Boiler Calculations
367

Bise
Inches
...
%
678
xo
3
405
46 .540
38 | 10 675|
½ 13.840
¾4 | 19 | 1.050
1
25 | 1.315|
14 | 32 | 1.660
1½ | 38
2 | 50
2½ | 64
3 176
3½ 90
4 | 100
4½ | 113
5
125
8
9
10
10
10
11
12
12
Sise
Milli-
meters Inches
| 150
175
Diameters
| 200
200
225
250
❘ 250
250
External Approx-
imate
Internal
Inches
275
| 300
300
Nominal
Thickness
Inches
STANDARD WROUGHT PIPE
TABLE OF STANDARD DIMENSIONS
·
Circumference
.622||
.269|| .068 || 1.272| .845||
.364|| .088 || 1.696| 1.144||
.493|| .091 || 2.121| 1.549||
109 || 2.639| 1.954||
.824|| 113 || 3.299| 2.589||
1.049|| 133 4.131| 3.296||
1.380|| |__ .140
.1405.215 4.335|
5.969 5.058||
.154
.154 7.461 6.494||
Transverse Areas
External Internal External
Inches Inches
Sq. Ins.
.129
.229
.358
.554
.866
1.358|
2.164|
2.835|
4.430|
Internal
Sq. Ins.
057
104
191
3041
5331
864
•
Length of
Pipe Con-
taining One
Cubic Foot
Feet
9.431| 14.199|| 2533.775||
7.073| 10.493|| 1383.789||
.167 5.658
.250|| 4.547
*.333|| 3.637
.494 2.904
.669 2.301| 2.767||
2.372||
1.847||
1.547||
1.245||
1.076||
.948||
.847||
Metal
Sq. Ins.
072||
125||
Length of Pipe
Per Sq. Foot of
ExternalInternal
Surface Surface
Feet
Feet
1.495
| 1.900| 1.610||||| .145
2.036| .799 2.010|
| 2.375| 2.067||
3.355 -1.075||__ 1.608
| 2.875| 2.469|| .203 || 9.032| 7.757|| 6.492| 4.788 1.704|| 1.328
3.500| 3.068|| 216 ||10.996| 9.638|| 9.621 7.393 2:228|| 1.091
4.000 3.548|| .226 ||12.566|11.146|| 12.566] 9.886
4.500 4.026||:237 14.137|12.648|| 15.904| 12.730|_3.174|||
5.000 4.506||___.247 ||15.708|14.156|| 19.635| 15.947
5.563| 5.047|| .258
2.680|| .954
.8481
.7631
.6861
17.477|15.856|| 24.306| 20.006
|| |20.813|19.054||_34.472|_28_ 891
||23.955|22.063|| 45.664| 38.738
| 6.625| 6.065|| .280
7.625| 7.023|| .301
.277
.277
.576
5.581
6.926||. .500
7.265||
| 8.625| 8.071||
8.625 7.981||
27.096|25.356|| 58.426 51.161
.322 ||27.096|25.073|| 58.426| 50.027|
.342 ||30.238|28.089|| 72.760| 62.786|
8.399|||
9.974||
.279 ||33.772|32.019|| 90.763| 81.585 9.178||
||33.772|31.843||
9.625 8.941||
10.750|10.192||
10.750|10.136|| .307 ||33.772 31.843|| 90.763 80.691| 10.072||
10.750|10.020|| .365 33.772 31.479|| 90.763 78.855| 11.908||
|11.750|11.000|| .375 ||3
.375 36.914|34.558||108.4341 95.033| 13.401|
12:750|12.090|| .330 ||40.055 37.982||127.676|114.800 12.876||
12.750 12.000|| .375 ||40.055137.699||127.676 113.097 14.579||
3.688||
4.300
.756||
.629||
.543!|
442|| .473||
442 .478||
.396
.427||
.355
.374||
.355
.355
.3251
.299
299|
244
.424
7.747|| 754.360|| 567
6.141|| 473.906|| 850
4.635|| 270.034||
3.641|| 166.618||
96.275|
70.733
.376||
.381||
.347||
.315!
.318||
Nominal Weight
Per Foot
-
Plain
Ends
Threaded
and
Coupled
42.913
30.077|| 5.793|
19.479 7.575
Number of
Threads per
Inch of
Bcrew
245||
27
.425||
18
568|| 18
..852 14
1.134|| 14
1:130|
1.678| 1.684|| 11/1/2
2.272| 2.281 11/2
2.717
2.717| 2.731||
3.652| 3.678|| 11/2
5.819
7.616
11½
8
8
8
8
8
8
8
8
8
8
8
8
8
8
14.565 || 9.109| 9.202||
11.312 || 10.790] 10.889||
9.030 || 12.538| 12.642||
7.198 || 14.617|_14.810||
4.984 || 18.974| 19.185||
3.717 || 23.544| 23.769||
2.815 || 24.696| 25.000||
2.878 || 28.554| 28.809||
2.294 || 33.907| 34.188||
1.766 || 31.201| 32.000||
1 785 || 34.240| 35.000||
1.826 || 40.483| 41.132||
1.545 || 45.557| 46.247||
1.254 || 43.773| 45.000|| 8
1.273 || 49.562 50.706|| 8
co 100 100 100
368
Boiler Calculations
Nomb
DAL Exter-
Inter- Dal
nai
Inches Inches
.405
.540
K
X
.675
.840
1 050
3/
1
44
1
1/
114
2
21/2
3
3/2½
4
41½
5
6
7
8
9
10
11
12
Nomt
nsi
Inter-
pal
DIAMETER
244
3
314
4
4/2
5
6
7
8
DIAMETER
Exter-
nai
Inches Inches
1½ 840
1.050
1.315
1/ 1.660
1
144
1.900
2
2.375
1.315
1.660
1.900
2.375
2.875
3.5.00
4.000
4.500
5.000
5.563
6 625
7.625
8.625
9.625
10.750
9.750
11.760 10.750
12.750
11.750
2 875
3 500
Approxi- | Nominal
mute Thickness
Internal
Diameter
Inches
.213
302
4.000
4 500
5 000
5. 563
.423
.346
742
6.625
7.625
.957
1.278
1 500
1.939
2.323
2.900
3.364
3.826
4.290
4 813
5.761
6.625
7.625
8 625
Properties of Extra Strong* Pipe
TRANSVERSE AREAS

mate
Internal
Diameter
Inches
.095
1.19
126
147
154
.179
191
200
218
.276
.300
.318
337
355.
Nominal
Approxi-Thickness
External Internal
Metal
Sq. Inches Sq. Inches Sq. Inches
.036
129
093
.157
.072
.141
.217
.320
234
433
.639
.831
6.092
1 068
1:477
2.254
7.298
9.111
3 016
10.568
3.678
12.020
4.407
5.180
.375
13 477
15.120
18 099
15.904
19.635
24 306
34.472
45.664
6.112
432
8.405
500
20 813
11.192
500
12.763
.500
23 955
27.096
30 631
58 426
72.760
90.763
33 772 108.434
36 914 127.676 108.434 19.242
500
58 428 14.334
74.662 16.101
90.763 17.671
500
500
Properties of Double Extra Strong* Pipe
CIRCUMFERENCE
552
600
External Internal
Inches Inches
1 272
.875
1 696
.949
2 121
1.329
2. 639
1.715
2 331
3.007
4 015
4 712
.636
.674
710
.750
804
.875
.875
3.299
4.131
5 215
$ 969
7.461
9 032
10.996
12.566
14 137
15 708
17.477
20 813
23 955
27.096
30.238
33.772
36 914
40.055
CIRCUMFERENCE
Inches Inches
.294
2.639
3.299
3ug
358
4.131
.382
5 215
.400
5.969
.436
7.461
9.032
10 996
229
358
554
Inches
.792
1.363
1 882
2 815
3.45G
4 722
5 664
7.226
8 570
9 902
11 247
12 764
15 384
18 457
21 598
.866
1.358
2 164
2.835
4.430
6.492
9 621
12 566
433
.719
1.283
1.767
External | Internsi External Internal Metal
·
2 953
4 238
6.605
8 888
11 497
14 455
TRANSVERSE ÁREAS
866
1 358
2 164
18.194
26.067
34.472
45.663
Sq. Inches Sq. Inches Sq. Inchca
.554
.050
.504
.148
.718
1.076
.282
.630
950
1.774
1 534
1.885
2 656
2.464
4 028
Inches
.252
.434
599
.896
2 835
1 100
1.503
1.771
4 430
6.492
9.621
2.300
2.728
12.566
3 152
14.137
15.708
3 550
4 063
12.566
15.904
19.635
24 306
34.472
45 664
4 897
17.477
20 813
23.955
27 096
5 875
58 426
8 625 6 875
Note.—Sizes 3½½ inch and larger are made by telescoping.
*NOTE.-The word heavy was formerly used in place of strong.
LENGTH OF PIPE PER
SQUARE FOOT of
4 155
5 845
7 803
10 066
12.966
18.835
27 109
37 122
External
Surface
5.466
6.721
8.101
9.569
11.340
15.637
18 555
21 304
Feet
9.431
7.073
5.658
4.547
3.637
2.904
2.301
2.010
1 603
1.328
1.091
.054
.848
.763
.686
.576
.500
.442
.323
353
323
299
External
Surface
Internal
Surface
Feet
4.547
3.637
2. 904
2.301
2 010
1.608
1.328
1.091
.954
.848
.763
.686
576
LENGTH OF PIPE PER
SQUARE FOOT OF
.500
442
Feet
17.766
12.648
9.030
6 995
5.147
3.991
2 988
2.546
1.969
1 044
1 317
1.135
.998
.890
.793
.663
.576
.500
.442
391
.355
.325
Internal
Burface
Feet
15.157
8.801
6.376
4.263
3.472
2.541
2.156
1.600
1.400
1 211
1.066
.940
.780
650
.555
Nomi
nai
Length of
Pipe Con-
taining Weight
One Cubic per Foot
Foot
Feet
Plain
Enda
Pounds
314
535
3966.392
2010.290
1024.689 738
615.017 1.087
333.016 1.473
200.193 2.171
112.256 2.996
81.487 3.631
48.766 5.022
33.976 7.681
21.801 10.252
16.202 12.505
12.525 14.983
9.862 17.611
7.915 20.778
5.524 28.573
4.177 38.048
3.154 43.388
2.464 48.728
1.929 54.735
1.587 60.075
1.328 65.415

Nom!.
Dal
Length of
Pipe Con-
taining Weight
One Cubic per Foot
Plain
Foot
Ends
Feet
2887.164
Pounds
1.714
•2 440
3.659
5.214
6.408
81.162
9 029
13.695
58.457
34.659 18.583
24.637❘ 22.850
973.404
$10.998
228.379
151.526
18.454 27.541
14.306 22.50
11.107 38.552
7.646 53.16Q
5.312 63.070
3.879 72.424
NOTE.-Pipe practice or customs of the trade: Orders for pipe larger than 12 in. should
specify the actual outside diameter of the pipe and the thickness of the wall. Standard weight
pipe is listed and carried in stock threaded and coupled and will be shipped unless order spe-
cified otherwise. Extra strong, double extra strong, hydraulic, and large o.d. pipe is listed
plain ends only and will be so shipped unless order specifies otherwise. An extra charge is
made for threads and couplings on these weights. For pipe smoothed on the inside, known
as reamed and drifted, an extra charge is made. Such pipe is furnished in random lengths
20 feet and shorter. Random lengths of extra strong and double extra strong pipe are con-
sidered to be 12 to 22 feet, dealer to have privilege of supplying not to exceed 5 per cent of
total order in lengths 6 to 12 feet. For cut lengths of any size an extra charge above random
lengths will be made. For galvanized or asphalted pipe an extra charge above black will be
made. Sizes 8, 10 and 12 inch standard pipe are listed in several weights and orders or inqui-
ries should specify the weight required.
Boiler Calculations
369
On what is horse power Code rating based for a through
tube vertical boiler?
Ans. On the inside diameter and only that part of the tube
covered with water which is up to the middle gauge cock. No
allowance is made for the surface of the length of the part of
the tube above the water level.
What may be said in favor of the Code rating?
Ans. Not much, it's ridiculous.
Why?
Ans. In the first place, the water does not remain stationary
at the middle gauge cock, but varies all over the glass, especially
with inefficient or greenhorn water tending attendance. Sec-
ondly, although that part of the tube in contact with the steam
is not as efficient as that part in contact with the water, the
latter part for that matter is not as efficient as the furnace
heating surface.
In the old rating, by taking the outside diameter of the tube, more
or less allowance is made for thermal inefficiency of the tube above the
water level, that is, in contact with the steam.
Give another objection to the Code rating?
Ans. If a table of Properties of boiler tubes be not at hand,
it involves measuring thickness of tube or if gauge number of
tube be known, looking up decimal equivalent of gauge num-
ber, subtracting twice this decimal equivalent from outside
diameter of tube. This leaves an integer with a disagreeable
fraction of several figures which must be multiplied by 3.1416
to find inside circumference, with plenty of chance for mistakes.
How would you find the length of a 2 in. boiler tube
per sq. ft. of inside heating surface?
370
Boiler Calculations
Ans. A standard 2 in. boiler tube (from table) is No. 13 B.w.g.
whose decimal equivalent is .095 in. Twice thickness=2×.095
=.19. Inside diameter =2.19 1.81 in. Circumference = 1.81
X3.1416=5.686 in. Length per sq. ft. inside heating surface
144÷5.686
12
=2.11 ft.
Apply the old (external heating surface) rating for the
calculation just made.
Ans. Circumference = 2 X 3.14166.2832. Length per sq.
144÷6.2832
ft. outside heating surface =
=1.91 ft.
12
Another objection is, from long usage of the old rating, our sense of
proportion is based on that rating and does not work on any other
basis-might as well try to get used to temperatures Centrigrade
instead of Fahrenheit.
Mention some conditions upon which the number of
sq. ft. of heating surface per boiler horse power depend.
Ans. 1, Kind and quality of coal; 2, draught; 3, ratio of
heating surface to grate area; 4, type of boiler, etc.
In one test of an externally fired horizontal return tubular boiler, the
data was as follows: 1, Eclipse semi-bituminous coal; 2, draught .22 in.;
3, ratio of heating surface to grate area 42 to 1. H.P. developed during
test 147; horse power on 10 sq. ft. rating 144. Any well designed through
tube vertical shell boiler will develop 1 boiler horse power on 12 sq. ft.
of heating surface and on account of the variables just mentioned it
is not necessary to introduce any new rating.
Boiler Feed Pumps
371
CHAPTER 23
Boiler Feed Pumps
What is a feed pump?
Ans. The pump which supplies a boiler with "feed" water.
What is feed water?
Ans. The water supplied to a boiler to replace that evaporated
as steam or blown off.
What is the net feed water?
Ans. The quantity of water necessary to supply a stated
evaporation in a given interval of time.
What is the gross feed water?
Ans. The net feed water plus the quantity provided for that
blown out.
What two general classes of feed pump are used?
Ans. Reciprocating and centrifugal.
Name two kinds of reciprocating pumps classed in
general with respect to the method of drive.
Ans. 1, Engine driven; and 2, independent.
372
Boiler Feed Pumps
32-
47
S
72
SIMPLEX DOUBLE DECK PLATE PUMP
46
45
47
21.
31
69.
30
ܐ ܛ ܐ
73
66
I
42 43 44
62
63
64
33-
75
>
67
69
65
39
11
15.
74
-93
-51
92
D-50
2
52
25-0
16
26
72
10
27
-14
Figs. 1 to 11.-Sectional view of simplex double deck plate type pump. The names of parts corresponding
to the numbers are given on the next page.



Boiler Feed Pumps
373
1 Steam Cylinder
2. Pump Cylinder
3. Steam Chest
4. Steam Chest Head
5. Chest Piston
7
Valve Rod
9. Steam Cylinder Head
10. Pump Cylinder Lining
11. Piston Rod
14. Pump Cylinder Head
15. Discharge Valve Plate
16. Water Chest Cover
21. Steam Piston
25. Pump Piston Head
26. Pump Piston Follower
Sectional View and Parts List.
27. Fibrous Packing for Pump Piston
30. Clamp for Small Slide Valve
31. Small Slide Valve
32. Main Slide Valve
33. Cross Head
39. Piston Rod Gland
42. Bushing
43. Gland
44. Nut
45. Nut
46. Bushing
47. Starting Lever
50. Water Valve Seat
51. Water Valve Spring
52. Water Valve
·
For Valve Rod
Stuffing Box
For Starting Lever
Stuffing Box
62. Valve Rod Dog
63. Link
What is an independent feed pump?
Ans. One having its own power unit attached.
64. Lever
65. Stand
66. Valve Rod Dog Collar
67. Link Stud
68. Lever Stud
69. Steam Piston Ring
72. Piston Rod Nut
73. Steam Cradle Head
74. Pump Cradle Head
75. Cradle Bar
92. Plates for Valve
93. Valve Stem
94. Valve Guard
What does the term "engine driven" mean?
Ans. It means that the pump is driven direct by the main engine.
What are the advantages of the engine driven pump?
Ans. It has the advantage: 1, of the superior economy of the engine; 2, variable
speed proportional to the demand for steam by the main engine.
¿
374
Boiler Feed Pumps
INLET
A
COVER
EYE
D
E
с
B
Y W
E

IL
Figs. 12 and 13.-Cover and section of centrifugal pump commonly called a
volute pump on account of the shape of the casing. The illustrations show the
inlet, eye, discharge, etc.
the
#
F
DISCHARGE

Fig. 14.-Enclosed double inlet impeller. The impeller is cast in one piece of
bronze except in cases of pumping liquids requiring special metals, such as
chrome, monel, nickel or other suitable alloys.
I
375
Boiler Feed Pumps
What are the disadvantages of the engine driven pump?
Ans. It usually runs when direct connected at too high speed,
except on large engines and in some cases requires reduction
gears to obtain proper pump speed.
What is the advantage of an independent pump?
Ans. It can feed the boiler when the main engine is not
running.
M

1104000)
10000
X00000
KOD0001
Fig. 15.-Inside packed plunger. In construction, the plunger passes through
a stuffing box in the center of the cylinder. Not much can be said in favor of this
type and it should be used only with perfectly clean liquids-no foreign mat-
ter, as nobody knows what is going on inside during operation, that is to say,
leakage, unless excessive, is not indicated while the pump is in operation.
Totally unsuited to high pressure working with dirty water.
What are the disadvantages of an independent pump?
Ans. 1, Requires frequent adjusting of steam valve to main-
tain proper speed; 2, it requires about ten times as much coal
to run it as one driven by an economical engine.
The latter "feature" leaves no room for argument as to which is the
more desirable, especially in marine practice, notwithstanding the fact
376
Boiler Feed Pumps
that a large portion of the heat supplied to the independent pump may
be recovered through a primary, or secondary heater, exhausting into
receiver, etc.
What may be said in favor of the simplex feed pump?
Ans. Not much.
Why?
Ans. It has bad habits like the gas engine-refusing to run
at times from no apparent reason.

Con
Be
Fig. 13.-Double deck single plate outside center packed pump showing one
long plunger projecting into each single acting cylinder.
What may be said in favor of the duplex pump?
Ans. It is the most reliable-never stops except under most
extraordinary circumstances.
What may be said against the duplex pump?
Ans. The most wasteful of steam-in other words, a "steam
eater."
Boiler Feed Pumps
377
What are the various forms of transmission for an engine
driven pump?
Ans. 1, Direct connection to cross head; 2, walking beam;
3, reduction gears; 4, eccentric; 5, Scotch yoke.

LONG RCCKEL
CROSSHEAD
Fig. 17.-Outside end packed pot valve plunger pump showing arrangement and
accessibility of the stuffing boxes.
1
民
​
CRADLE
DIVIDED
PISTON ROD
LINER
WATER CYLINDER
VALVES
VALVE COVER
PISTON
SOFT PISTON PACKING
Fig. 18.—Water end detail of a horizontal duplex double deck turret pump.
A
378
Boiler Feed Pumps
10
"
GAIREBESTIU)
CROSS
HEAD
DRIVE
ומטי
B
ECCENTRIC
WALKING
BEAM
FEED
PUMP
m
SCOTCH YOKE
AIR
PUMP
WALKING
BEAM
REDUCTION
GEARS
Figs. 19 to 23.—Various
methods of driving en-
gine driven feed pumps.
Fig. 19 direct cross
head drive; fig. 20,
walking beam cross
head drive; fig. 21,
walking beam reduc-
tion gear; fig. 22, ec-
centric drive; fig. 23,
Scotch yoke drive.

Boiler Feed Pumps
379
PACKING
You
FOLLOWER

n
WATER PISTON
Fig. 24.-Pump water piston with divided piston rod. A water tight joint with the
cylinder walls is obtained usually with several rings of fibrous packing as
shown, which are held in place by a shoulder at one end of the piston and the
follower or follower plate at the other.

Figs. 25 and 26.—Split cross head showing divided piston rod ends in position.
380
Boiler Feed Pumps
Example. - What diameter of a plunger is required for a single acting
pump cross head drive, to deliver 600 lbs. of feed water to the boiler
when operated by a 10 inch stroke engine making 200 r.p.m.
600 ÷ 60
231 X (10 ÷ 8%)
The pump being single acting, makes one delivery stroke per revolu-
tion of the engine, hence,
displacement per delivery stroke
600 lbs. of water per hour
10 lbs. of water
VALVE SEAT
*****
>>
PORT
=
=
For 10-inch stroke, cross sectional area of plunger
1.385 10
.1385 sq. ins.
୮
†Diameter corresponding = √
10 lbs. per minute.
277 cu. ins.*
277 ÷ 200 = 1.385 cu. ins.
=
12
.1385
.7854
.42, say 16

LIFT
PORT OPENING
Fig. 27.-Sectional view of valve and seat illustrating terms lift and port open-
ings.
VALVE
*NOTE. One gallon of water weighs 8 pounds, and occupies 231 cubic
inches at 62° Fahr.
NOTE.-Area of circle = .7854 X diam.² diam.
area
.7854
Boiler Feed Pumps
381
What is the worst type of independent reciprocating
boiler feed pump?
Ans. The direct connected, that is, having its steam drive
direct connected.
Why?
Ans. These pumps require about 120 lbs. of steam per horse
power when in good condition, but considering the average
condition as to hydraulic leakage, 200 or 250 lbs. would be
a safer figure.


I
這
​RABBRI
KINGHORN VALVE
BRONZE VALVE
Figs. 28 and 29.-Kinghorn and bronze valves. The Kinghorn valve, fig. 28, is
composed of three or more thin bronze plates. This is often preferred over the
bronze valve because of its light weight. The bronze valve is suitable for hot
water.
In one experience of the author more water leaked back of the piston
than was being pumped into the boiler considering the excessive speed
necessary to maintain a two gauge water level in the boiler. Such
condition is not an inherent defect, but can be attributed to greenhorn
or neglectful attendance, because when the author put the water end
in proper condition the output was adequate at slow speed.
Why are these "steam eaters" used?
Ans. One prominent writer says: "As the power required for
pumping the feed water is only a small portion of the entire
3882
Boiler Feed Pumps
ENGINE
FEED INLET-
PRIMARY HEATER
TO BOILER
PUMP
STEAM END
ENGINE
REDUCING
FEED
VALVE
FEED INLET-
PRIMARY HEATER
FEED TO BOILER
PUMP EXHAUST
PUMP
ர
ZA
CONDENSER
SECONDARY HEATER
CONDENSING
NON-CONDENSING
Figs. 30 and 31.-Feed water heater method of improving the efficiency of a direct connected pump. Fig. 30,
non-condensing connections; fig. 31, condensing connection. In fig. 31 the exhaust for the pump is piped to
the main or primary heater and a large part of its heat is recovered in heating the feed water. When a con-
denser is used as in fig. 31, a small or secondary heater should be provided, into which the pump exhausts.
Any steam that is not condensed in the secondary heater passes to the primary heater, a reducing valve being
placed between the two heaters so as to maintain a predetermined pressure in the secondary heater. In oper-
ation, the feed water in passing through the primary heater is heated to temperatures ranging from 110° to
130°, more or less depending upon the vacuum maintained in the condenser. The water thus heated now passes
through the secondary heater where additional heat is imparted to it from the exhaust of the pump and other
auxiliaries, its final temperature being within a few degrees of that of the exhaust. By means of the adjustable
reducing valve, evidently any pressure desired may be maintained in the secondary heater, thus varying the
back pressure on the pump and its working temperature range to some value as may be found by test to give
the best economic effect. Of course increasing the back pressure involves increasing the size of the pump
cylinder to do the work.


Boiler Feed Pumps
383

COMPOUND
ENGINE
H.P. CYL.
HEBEN
L.P. CYL.
REHEATING
RECEIVER
PUMP
CONDENSER
-PUMP EXHAUST
TRIPLE
EXPANSION
ENGINE
H.P. CYL.
REHEATING
RECEIVER
INT.
CYL.
STEAM FROM
RECEIVER
JESSIN
CONDENSER
L.P CYL.
7
STEAM. FROM BOILER
Figs. 32 and 33.-Compounding method of improving the efficiency of a direct connected pump. Fig. 32,
arrangement with compound engine; fig. 33, arrangement with triple expansion engine. In fig. 32, the pump
receives its steam from the boiler, and exhausts into a reheating receiver where more or less of the condensate
it contains is re-evaporated. The exhaust then does useful work in the 1.p. cyl. In fig. 33 steam is taken from
the receiver and exhausted into the condenser. If the pump be suitable for high pressures, a more economical
arrangement would be to take steam from the boiler and exhaust into the receiver, thus obtaining the ad-
vantage of expansion in the int. and 1.p. cyls.
EXHAUST TO
/CONDENSER
PUMP
NOTE.-Selection of boiler feed pumps. Either two small pumps may be installed, using one at high
speed and using the other as a spare, or one large pump may be installed and run at slow speed, using an injector
in case the pump break down. Evidently in the first instance if the growth of the plant require increased boiler
capacity both pumps must be run at the same time, hence there is no reserve pumping capacity in case of break
down to one. With the large pump and injector, there will be considerable margin to meet the increasing load
without using both pump and injector at the same time. If a line shaft be available, a power pump with gear or
belt transmission is desirable, using an injector for emergency feed and while the main engine is idle, there should
always be two devices (as two pumps or a pump and an injector) for feeding the boiler to guard against interruption
in case of break down of one
384
Boiler Feed Pumps

DIAM
16 THREADS
t/
8/59
·1%8⋅
32 SLOT
1%
Neo 1x
9/6 BALL
HARDENED
16 THREADS-
-*/<!
5.
-5%
हरा
½ PIPE TAP
- DRILL
amount, an extremely uneconomical
pump does not represent a great per-
centage of the entire fuel."
What can be said about this line of
talk?
Ans. It cannot be too strongly con-
demned.
The Simplex System.-The word
simplex is here used to distinguish the
single cylinder direct acting pump from
the two cylinder duplex or twin type.
Henry R. Worthington in 1840 invented
the simplex or direct acting reciprocat-
ing pump. In this pump the essential
feature is that the movement of the steam
piston (which is direct connected to the
water piston or plunger) is automatically
operated by the movement of the steam
piston.
Figs. 34 and 35.—Graham engine driven feed pump. Note the absence of air
chamber. The author, who had many years' experience designing large
pumps for city water works found that the so-called air chambers were virtually
water chambers, because unless means were provided to keep them filled with
air, they soon became filled with water and ceased to perform their function of
cushioning the shocks. Accordingly such device is here dispensed with, and a
spring cushion provided which is expected to absorb the shocks even at high
speed. No valves are built into the pump casting, a tee fitting and two check
valves being used, connected with close nipples.
Boiler Feed Pumps
385
Ques. What is the difficulty in obtaining automatic action
at the steam end?
Ans. The necessity of providing a special valve gear, some-
what complicated, is because of the absence of a rotating part
which prevents the use of an eccentric.
Simplex Pump Valve Gears.-In most cases the necessary
movements of the valve gear are obtained from three sources.
1. The movement of the piston
2. The movement of the piston rod
3. The steam pressure
A valve gear thus operated usually consists of:
1. A main valve
Which admits and exhausts steam from the cylinder.
2. An auxiliary piston
Connected to the main valve and moving in a cylinder formed on the
valve chest.
3. An auxiliary valve
Controlling the steam distribution to the auxiliary piston cylinder and
operated with suitable gear by the main piston or piston rod.
Ques. How does the gear just mentioned work?
Ans. As the main piston approaches the end of the stroke,
it moves the auxiliary valve.
Ques. What results from this movement?
Ans. It causes steam to be admitted to one end of the auxil-
iary piston and exhausted from the other resulting in a move-
ment of the auxiliary piston.
Ques. What happens when the auxiliary piston moves?
Ans. The movement of the auxiliary piston moves the main
valve.
}
386
Boiler Feed Pumps
The steam distributed to the main cylinder, thus affected, reverses the
motion of the main piston, and the return stroke takes place, completing the
cycle.
Ques. What detail varies mostly in pumps of different
makes?
Ans. The auxiliary valve and the method by which it is
operated.
With respect to these features the majority of pumps may be divided into
two classes as these having:
1. A separate auxiliary valve.
2. Auxiliary valve and auxiliary piston combined.
Simplex Gears with Separate Auxiliary Valve.-In pumps of
this type the auxiliary valves usually have stems or tappets
which project into the cylinder at the ends and are moved by con-
tact with the main piston as it nears the end of the stroke.
An example of this class is shown in fig. 36.
Each auxiliary valve I has a short stem which projects into
the cylinder.
Ques. What happens when the piston strikes one of the aux-
iliary valves I?
Ans. The valve is driven back and opens an exhaust pas-
sage E, from the corresponding end of the auxiliary piston F,
which immediately shifts under pressure of live steam on the
opposite side of the auxiliary piston head.
Ques. What is the object of the little hole in each end of
the auxiliary piston?
Boiler Feed Pumps
387
Ans. When both auxiliary valves are closed the steam pass-
ing through these holes leaves the auxiliary piston entirely sur-
rounded by live steam and accordingly in perfect balance end-
wise.
Ques. How long does this balance last?

114
VIRUZULO
JUG
AC
E
Fig. 36. -Simplex pump of the separate auxiliary valve type. In operation,
the piston as it nears the end of each stroke strikes the stem and lifts the valve (1)
off its seat. This allows the exhaust steam behind the piston valve to escape.
The live steam pushes the piston toward the exhausted end carrying the main
slide valve along with it.
Ans. Until the main piston strikes the stem in the opposite
cylinder head, at which time the valve moving operations are
repeated in the opposite direction.
388
Boiler Feed Pumps
Ques. With what does the space back of the auxiliary valves
communicate?
Ans. The steam chest.
The connecting passages are shown in dotted lines. The valve is there-
fore closed by steam pressure as soon as the piston moves back from the
stem.
Ques. What should be noted about the piston?
Ans. It closes the exhaust passage before the end of the
stroke.
Ques. What is the reason for this?
Ans. To trap the steam so as to form a cushion between the
piston and the cylinder head.
Ques. How is the piston started on the return stroke?
Ans. Sufficient steam is admitted through a little passage
cut in the cylinder wall to start the piston.
Ques. How does the auxiliary valve shift the main valve?
Ans. In the direction of the piston travel at the end of the
stroke, that is, opposite to that of a common slide valve.
This valve therefore has two cavities, each of which alternately puts the
cylinder in communication with the steam chest and the central exhaust
port.
In fig. 36 is a lever L by means of which the auxiliary piston may be re-
versed by hand when expedient.
Boiler Feed Pumps
389
N
Simplex Gears with Auxiliary Valve and Auxiliary Piston
Combined. With this arrangement an initial rotary motion is
given the auxiliary piston by the external gear causing it to

H
O
M
D
O
BULA
F
Wil
A
EH
"ET"
N
TU
BAZ
C
M
B
M,B
D
F
Figs. 37 to 39.-Simplex pump of the combined auxiliary valve and auxiliary.
piston type as described in the text.
390
Boiler Feed Pumps
uncover ports which give the proper steam distribution for its linear
movement.
An example of this class is shown in figs. 37 to 39.
The main valve is operated by a positive mechanical connection between
it and the main piston rod, also by the action of the steam on the valve
pistons.
Figs. 37 to 39 shows the details of the valve gear and steam
cylinder.
Ques. Describe the construction referring to figs. 37 to 39.
Ans. The steam end consists of the cylinder M, valve A, and
valve pistons B and B. These pistons are connected with suffi-
cient space between them for the valve A, to cover the steam
'ports F and F, as in fig. 39.
Ques. How is the valve operated?
Ans. By the steel cam C, (fig. 37) acting on a steel pin D,
which passes through the valve into the exhaust port N, in
which the cam is located.
Ques. What is provided in addition to this positive motion?
Ans. Steam is alternately admitted to and exhausted from
the ends of the valve piston through the ports E and E, which
moves the pistons B and B,fig. 38.
Ques. Describe the operation of the pump.
Ans. Assuming the pump to be at rest with valve A, cover-
ing the main steam ports F and F in which position the cam C,
holds the main steam valve by means of the valve pin D, so
that ports E and E, admit steam to one end of the valve piston
at the same time connects the other end with the exhaust port.
Boiler Feed Pumps
391
The steam acting on the valve pistons moves both, opening the
main ports F and F admitting steam to one end of the steam
cylinder and opening the other end to the exhaust.
Ques. What happens if the valve occupy any other position
than the one described?
Ans. The main ports F and F will be opened for the admis-
sion and exhaust of steam.
It is accordingly clear that the pump will start from any point of the
stroke.
Ques. What happens on the admission of steam to the
cylinder?
Ans. The main port F, the main piston, cam and valve will
move in the direction indicated by the arrows in fig. 39.
Ques. What does the first movement of the cam do?
Ans. It oscillates the valve preparatory to bringing it into
proper position for the opening of one of the auxiliary steam
ports E, to live steam, and the other to exhaust, also to close
the valve mechanically just before the main piston reaches the
end of its stroke.
This causes a slight compression and fully opens one of the ports E, to
steam and the other to exhaust. By the admission of steam to one end, the
other being open to the exhaust, the valve pistons move the valve to allow
the admission and exhaust of steam from the cylinder for the return stroke.
Simplex Gears Piston Steam Valve Type.-The single direct
acting pump steam valve mechanism here described is a recent
development. Changing conditions of service, increasing steam
pressures, and high temperatures have necessitated the use of
piston steam valves in replacement of the conventional slide
392
Boiler Feed Pumps
|| 19 18 22 24 12
씽
​571
24 54 57 572 491 53 52 47 42
#D
2 1 1 35 3
Figs. 40 to 42.-Simplex pump gears, piston steam valve type.
9 7 33 254 26 34 391 344
A-3290
38
39
47 48
valve heretofore employed, for the reason that the movement of large, unbalanced
slide valves may be sluggish, resulting in uneven and noisy pump operation, and in
rapid wear on the steam valve and on the cylinder face on which the valve operates.
This gear is designed not only for high pressure high temperature steam, but also for service
where the pump must operate without steam cylinder lubrication, as in marine installations.
In the valve operating mechanism shown in figs. 40 to 42 the reciprocating motion
of the piston rod is transmitted to the

Boiler Feed Pumps
393
pilot valve 11, through the piston rod spool 34, the lever 39,
the lost motion block 47, adjustable valve rod link 491, with
tappet collars, and the steam valve rod 54. The small pilot
valve is of the D slide type.
The slide type pilot valve is used in this new gear, as such a valve is
more easily tightened originally and reconditioned when worn, than is a
piston valve of the very small size which would be required in these pumps.
The pilot valve is inverted and operated on a separate valve plate with
both the plate and the valve readily removable, without disturbing any
other parts.
Steam and exhaust ports drilled in the pilot valve plate register with
ports drilled in the steam chest 18, which ports lead to the ends of the
piston valve chamber in the chest and to exhaust opening.
Reciprocation of the pilot valve alternately admits steam to and permits
exhaust from the chamber in which the piston valve operates. This piston
valve chamber in the chest is bored and honed for the reception of the
ground piston valve. This piston valve 12, in turn reciprocates, admitting
steam alternately from the chest to the two ends of the main steam cylinder
and from the cylinder to exhaust. This alternate admission of steam to
the ends of the main steam cylinder with synchronized exhaust from the
opposite end results in the required reciprocating movement of the steam
piston 7, in the steam cylinder 1. The steam valve is of the balanced
piston type.
The provision for externally changing the length of travel of the pilot
valve permits easy adjustment of the valve gear to care for wide variations
in speed and in relative pressures in the steam and liquid ends of the pump.
The steam chest is constructed with five main ports. Live steam
enters through the two outside ports. The two intermediate ports connect
to the ends of the cylinders and are combined steam inlet and exhaust
ports. The central port is the exhaust outlet.
In fig. 40, the steam inlet to the chest is at the left and the
exhaust at the right. The chest is symmetrical and can be re-
versed if required to provide steam at the right and exhaust at
the left.
In the piston valve 12, three ports are provided, the two outer ports
for steam inlet and the center for exhaust. The valve is hollow and the
394
Boiler Feed Pumps
steam ports intercommunicate. There is consequently a flow of steam
from two sources when the ports are uncovered. There is but one main
port to each end of the main steam cylinder. Two communicating open-
ings are provided between each of these ports and the cylinder bore.
The small opening at the end of the cylinder has two functions. Through
it, a small volume of steam is admitted to the cylinder at the beginning
of the stroke, while the piston covers the inner and larger ports, preventing
admission of steam at that point.
By retarding the admission of steam at this beginning of the stroke,
the moving parts of the pump and water column are gradually actuated up
to the point where the main steam port is uncovered by the steam piston,
thus insuring that the pump will operate without shock or water hammer.
When the piston advances so that the inner, larger steam port is un-
covered, steam enters the cylinder through both openings. Near the end
of the stroke, the larger inner port through which the spent steam has been
passing to exhaust, is closed by the piston.
The steam remaining in that end of the cylinder is, therefore, trapped
and compressed, providing cushion to absorb the inertia of the moving
parts and of the water column and giving smooth, quiet deceleration.
As the trapped steam then passes out through the starting port, the piston
continues its movement slowly until reversal occurs.
The stroke of the pump may be lengthened by an increase in
the distance between the nuts on the outside adjustable valve
link.
·
This increase in the lost motion retards the movement of the pilot valve.
Conversely, a decrease in the amount of the lost motion will result in a
corresponding shortening of the stroke of the pump. In general, it is
desirable to so adjust the lost motion as to give the longest possible stroke
attainable, without permitting the piston to hit the heads, as a long stroke
results in most satisfactory operation and minimum steam consumption.
The Duplex System.-By definition, a duplex direct acting
pump is a combination of two pumps arranged side by side and
so connected that the piston rod of one pump in making its stroke,
acts through a simple mechanism to move the valve which admits
steam to the cylinder of the other after which it finishes its stroke
Boiler Feed Pumps
395
and waits for its own steam valve to be acted upon by the movement
of the piston of the other side before it can make its own return
stroke.
Ques. Name a desirable characteristic of the duplex pump.
Ans. There is no dead point at any stage of the stroke.
Ques. Why?
Ans. Because one or the other of the steam ports is always
open.
Ques. What is the comparison between duplex valves and
simplex valves?
Ans. The valves of a duplex pump are mechanically operated
and not the steam thrown valves necessary with the simplex
pumps.
Ques. Why does a duplex pump have five ports for each
cylinder?
Ans. In addition to the three ports necessary for operation
two other ports are required to provide cushioning.
It will be seen from fig. 44, that the valve seat has five ports, giving
separate steam and exhaust passages and a central exhaust cavity as shown.
The passages Q and K, nearest the ends are steam passages, and the inner
passages O and R, are for exhaust These inner passages are covered
or closed by the piston just before the end of the stroke whereby a portion
of the exhaust steam is compressed and made to act as a cushion between
the piston and cylinder head, thus preventing the piston striking the
cylinder heads when operating at high speed.
Ques. Describe the steam distribution with the piston ap-
proaching the end of the stroke.
396
Boiler Feed Pumps
VALVE GEAR
DISC POPPET TYPE
VALVE SERVICE
DEEP STUFFING BOXES
FOR ALL RODS
DY 78602
W.7732
SHAD
Co
CENTRIFUGALLY CAST
LINERS
DIVIDED
PISTON ROD
PACKING RINGS
Fig. 43.-Simplex horizontal pump showing general construction. See page 280 for duplex pump construction.

Boiler Feed Pumps
397
·
H
Ans. In the position shown in fig. 45, the valve covers four
ports. Steam is here admitted through the passage at the right
end, causing the piston to move as indicated by the arrow.
During this the steam port at the other end is closed and the
exhaust port at that end is open, but the exhaust passage is
closed by the piston, which traps some of the steam and cushions
the piston.
STEAM
EXHAUST
G
1

Ans. By cushion valves.
R
Ques. Where are they located?
K
EXHAUST
F
EXHAUST CAVITY
H and F are the steam
Fig. 44.-Duplex pump steam valve and valve seat.
edges of the valve and G and I, the exhaust edges. Q and K are the steam
ports and O and R the exhaust ports. The exhaust cavity is at the center.
Note there are five ports in all.
STEAM
Ques. How is the degree of cushioning regulated in some
pumps?
398
Boiler Feed Pumps
Ans. These valves are placed in a passage leading from the
steam port to the exhaust port at each end as indicated in fig.
45.
Ques. Explain their operation.
Ans. When a cushion valve is partly open, some of the steam
compressed in the clearance space and its steam port escapes
into the exhaust port, thus reducing the cushioning effect.
Ques. What effect has this on the piston movement?

P
AUT
T
MANTRIE
Fig. 45.-Steam end of Duplex pump showing cushion relief passages.
Boiler Feed Pumps
399
EXPANSIVE WORKING VALVE
(FOR FLY WHEEL PUMPS)
OUTSIDE LAP

STEAM PORT
CO
NO
OUTSIDE LAP
INSIDE LAP
CENTRAL OR NEUTRAL
POSITION
EXHAUST PORT
Fig. 46.-Expansive working valve for fly wheel pump. In this class of pump
the dynamic inertia stored up in the fly wheel during the first part of the stroke
(up to cut off) keeps the pump going during the expansion period where the
pressure in the steam cylinder is not high enough to overcome the resistance
at the water end.
NON-EXPANSIVE WORKING VALVE
(FOR DIRECT CONNECTED PUMPS)
n
Fig. 47. Non-expansion working valve for direct connected pump. The
absence of lap allows the cylinder to take steam the full length of the stroke.

NO
INSIDE LAP
400
Boiler Feed Pumps
Ans. The piston moves closer to the cylinder head before
it stops.
The need for cushioning increases with the speed of the pump. Where
the speed is increased it is necessary to increase the cushioning effect by
partly closing the cushion valves. These valves provide a simple means
of obtaining a full stroke of the piston without danger to the pump whether
its speed be fast or slow.
Ques. How are the valves proportioned?
Ans. They have no outside lap nor inside lap.
Ques. What is lap?
Ans. It is that portion of the valve face which overlaps the
ports when the valve is in its central or neutral position, as in
fig. 46.
Ques. What is the difference between outside lap and inside.
lap?
Ans. Outside lap A B, is lap referred to the steam port and
inside lap C D, is lap referred to the exhaust port, as in fig. 46.
Ques. Why do the valves have no lap?
Ans. Because a direct acting pump must take steam the
whole length of the stroke and have no compression except that
needed for cushioning. See fig. 47.
According in neutral positions the valves just cover the steam ports
leading to opposite ends of the cylinders Note the relation as shown
in fig. 44.
Boiler Feed Pumps
401
LEFT STEAM
CYLINDER
The Duplex Pump Valve Gear.-The mechanism or gear
which operates the valves of a duplex pump consists (for each
cylinder) of a:
MISLITSE
1. Cross head
2. Long rocker arm
3. Rocker shaft
4. Short rocker arm
5. Connecting link
6. Valve stem
B
******
I CROSS HEAD
DUPLEX GEAR
(SET FOR ONE CYLINDER)
6 VALVE STEM

5 CONNECTING LINK
4 SHORT ROCKER ARM
3 ROCKER SHAFT
2 LONG ROCKER ARM
PISTON ROD
1420 M 398) 225, 14PJA DOULET
Fig. 48.-Duplex valve gear shown for one side of the pump.
RIGHT WATER
CYLINDER
B
402
Boiler Feed Pumps
On the pump there are two sets of these parts-one set for
each cylinder. However, in order to clearly show the assembly
one set only is shown in fig. 48.
Referring to the illustration, the source of motion for operating the valve
of the left steam cylinder is obtained from the piston rod of the cylinder
on the other side. As shown there is a cross head 1, attached to the rod
in which works a long rocker arm 2. The reciprocating motion of the rod
imparts an oscillating motion to the long rocker arm. This rocker arm is
attached to a rocker shaft 3.
The rocker shaft works in a long bearing which is not shown in order to
make working parts visible.
At the other end of the rocker shaft is attached a short rocker arm 4,
which in operation rocks or oscillates in unison with the long rocker arm.
The oscillating motion of the short rocker arm imparts a reciprocating
motion to the valve stem 6, through the connecting link 5.
Ques. Name one detail not shown in fig. 48.
Ans. Means for introducing "lost motion" in the operation
of the gear.
Duplex Valve Gear "Lost Motion."-There is always a lost
motion between the slide valve and the valve rod operating it so that
the valve does not move until the piston on the one side which oper-
ates it, has travelled some distance.
This affords a short pause in the flow of water at the end of a stroke
and gives the water valve an opportunity to seat quietly before the reverse
stroke takes place. The piston on the other side in the meantime having
renewed its movement, tends to lessen pressure and flow fluctuations.
Ques. How long is the lost motion pause in general practice?
Ans. From about one-quarter to possibly one-half the whole
stroke of the piston, depending upon the amount of lost motion
in the valve gear.
Boiler Feed Pumps
403
Ques. Is the lost motion adjustable?
Ans. On some pumps yes; on others no.
should be adjustable on all pumps.
The lost motion
"Lost Motion" Mechanism.-On some pumps this detail is
inside the valve chest where it can't be reached without stop-
ping, cooling the pump and taking off the valve chest head.
Such designing is stupid.
On other designs it is placed outside forming a part of the
connecting link,(5, fig. 48) where it ought to be easily accessi-
ble.
< "
The lost motion may be either
1. Fixed or
2. Adjustable
With this arrangement the lost motion may be adjusted while the pump
is in operation. In fact the pump should be in operation to properly
"tune up" the lost motion.
and the mechanism may also be classed with respect to location
as,
1. Inside
2. Outside
Fig. 49 shows an inside fixed or non-adjustable mechanism.
As shown, it consists of a block threaded on the valve rod, the block
being a loose fit between two lugs on the steam valve, the amount of space
between the block and the lugs constituting the lost motion.
This arrangement might go on very small or cheap pumps, but in a first
class design such makeshift would not be tolerated.
404
Boiler Feed Pumps
According to Raabe: "It is seldom the case that the amount
of lost motion has to be altered and unless the operator be thor-
oughly familiar with the details and design of the pump he
should not undertake such alterations, as the designer knows
best the requirements."
ENCLOSED INSIDE
LUG
.00
BLOCK
FIXED LOST
MOTION

+4
VALVE
→
00000
,000
LOST MOTION (ADJUSTABLE)
LUG
Fig. 49.-Inside fixed lost motion mechanism as made for very small or cheap
pumps.
ADJUSTMENT
CHEST

И И
Fig. 50.—Inside adjustable lost motion mechanism shown in detail.
Boiler Feed Pumps
405
D VALVE
DUPLEX GEAR
(ENTIRE)
D VALVE
C
J (POINTS UP)
ANDERT
G (POINTS DOWN)
-L
427911 TRUGHE STAJAKO SË SABE SE BAV
Fig. 51.-Duplex horizontal pump showing valve gear for D valves. See page 401 for single unit of this valve gear.

406
406
Boiler Feed Pumps
Duplex Valve Gear, Entire.-The complete valve gear, that
is, the two separate gears (one for each pump), is shown in fig.
51. It will be seen that although there are two "sets" of gears,
the parts making up the mechanism are the same for both
sides excepting long rocker arms C and L, which are of different
lengths.
It will also be noted that short rocker arm G (which is moved
by long rocker arm C) points down, while short rocker arm J
(moved by long rocker arm L) points up.
This arrangement of the short rocker arms is necessary in order that
one of the slide valves which they move (both valves being alike and of the
plain "D" type) shall admit steam at the opposite end of the steam cylinder
so as to reverse the piston stroke. With regard to the long and short rocker
arms, while they are of different lengths the two moving together have the
same ratio of lengths as the other two and as each rocker arms have the
same length of travel, the short rocker arms also move the same distance.
On account of the reversal of the short rocker arms (one pointing down
and the other up) the difference in long rocker arms is a mechanical necessity
in order to bring the valve rods to a common elevation. One unit of the
valve gear is shown on page 401.
Ques. On simplex pumps when is a D and B valve used?
Ans. The D valve is used on gears in which the valve follows
the piston movement; the B valve is used on gears in which the
valve moves in reverse direction to the piston movement.
Ques. What names are usually objectionably used for short
rockers and for long rockers?
Ans. Cranks for short rockers and levers for long rockers.
Duplex "D and B" Type Valve Gear.-In order to avoid the
separate passage at each end of the cylinder, a type of gear has
been devised which employs a D, valve on one cylinder and a
Boiler Feed Pumps
407
B, valve on the other cylinder. The difference between these
valves is shown in figs. 52 and 53.
Using a D valve and a B valve permits a unique arrangement of steam
passages.
The prime reason for this design as just stated is to get rid of the separate
passage at each end of the cylinder used for cushioning.
D VALVE
0
ソニ
​C D
7
Figs. 52 and 53.-Difference be ween D and B valves. The reason for these
two types of valves is explained in the text. B valves are used on pumps
having separate auxiliary valve in which the piston contacts with stems or
tappets which project into the cylinder at the ends.
b A
C
8 o' b'
C'
B VALVE



Fig. 54. -Valve seat illustrating ports.
a b c d
AND
abc'ď
A B C D EXHAUST PORT
STEAM PORTS

408
Boiler Feed Pumps
Ques. What mistake is usually made in using the word port?
wore a Parigny
camer
DICU 98
B
73
a
Fig. 55.-Top view of steam cylinders of a duplex D-B pump showing the
ports. Note only three ports to each cylinder. The two outside ports of
each cylinder are the steam ports and the center port the exhaust port.
00
Bolt of not
cami no b
ruraiff
10-.Et hp 22 gi
ovidy to say
owning vol
ara di fugget
27я09 MA3T2
Fig. 56,-Bottom of one B and one D valve forming a part of the D-B system.
Ans. Calling a passage a port.
Ques. What is the difference between a port and a passage?
Ans. A port is the entrance at the valve seat to either a

Boiler Feed Pumps
409
O
jobailys to grillagang esta
sgin leunites oft of gribnal
Fig. 57.-Top view of duplex D-B pump with valve chest cover removed showing
the D-B valves side by side also other details of the valve gear.
eton Figs. 58 and 59.-Views of ordinary duplex rockers and standard. pi
vlubny ne
bozup ofzow moote ant bno prinoideus tot oog trop
sonpipals apiol
410
Boiler Feed Pumps
steam passage leading to the cylinder, or 2, the exhaust passage
leading to the exhaust pipe.
It must be evident from the answer that a port has only 2 dimensions
and a passage 3 dimensions: in other words a port has area and a passage
volume.

11
R
9
3
D B
4
10
L
Fig. 60.-Duplex D and B, valve gear, the object of which is to avoid separate
exhaust passages for cushioning and the steam waste caused by an unduly
large clearance.
Boiler Feed Pumps
411
Ques. Describe the D-B valve gear.
Ans. The gear is shown in fig. 60, with the cylinders turned
each 90° for convenience in showing the rockers and steam
valves. All the parts are here plainly shown.
1 and 5 are D valve steam passages
2 6 B «
2 3
(6
46.
"
((
7
"
(
4
exhaust passages
8 "valve stem nuts
<<
Ques. What is the feature of the rockers 9 and 10?
Ans. They are duplicates and therefore interchangeable.
Ques. What is the object of the small drilled holes?
Ans. They are for starting.
Ques. Describe the starting passage and its action.
Ans. This is a small drilled passage which admits steam to
the cylinder when the piston covers the main passage as the
piston passes this passage when cushioning.
Maintenance
No piece of machinery can be expected to continue in satis-
factory operation unless it receive proper and periodic atten-
tion to correct any faults or derangements that may arise.
This comes under the heading of ordinary servicing rather than
repairs.
412
Boiler Feed Pumps
How about turbine driven centrifugal pumps as boiler
feeders?
Ans. They are very extensively used, especially in large plants
like Edison Stations.
Why?
Ans. Because they are continuous in action, put no severe
strain on the piping, if the feed valves were all shut off acci-
dentally, no dangerous pressure would result, less attention
required and saving in maintenance.
What type centrifugal pump is used?
Ans. Multi-stage, from two to five stage or more depending
upon the boiler pressure.
What is the steam consumption of the turbine driven
pump?
Ans. About the same as the ordinary slide valve engine, or
less depending upon the quality of the steam and other con-
ditions.
Reciprocating Pump Troubles
What causes a pump to fail to discharge?
Ans. 1, Pump not properly primed; 2, lift too high for tem-
perature of water; 3, inlet valves struck; 4, valve seats in bad
condition.
What should be the maximum lift for water at ordinary
well temperature?
Ans. Not over 22 feet.
Boiler Feed Pumps
413
How can hot water be handled?
Ans. To handle hot water, negative lift is necessary, in amount
depending upon the temperature of the water.
What is negative lift?


Crank End

222
218
262-
CO
82
220 A
mar
223
O
254 234 254
wwwwwww
о
о
www
18
I @
201 253
89
wwwwwwww
HSA
91
85
80
77
90
78
O
79
253 201
@ O
254
234
219
223
220
11
39
#*•*£*•
01187 B
72
Fig. 61.-Crank end of horizontal duplex double acting piston pump. See page
415 for list of parts.
414
Boiler Feed Pumps


Water End
220A
247
222
254
233
NOW
255
267
SERIAL NE
All Metal Wing Valve Assembly
265
268
51
52
-50
0946
52
SO
264
234
25
220
254
223
201
01187-A
253
28
15
88
K
52
264
10
25
27
98
94 93


TAFT
26
225
BUOKUCHIPNUOVOU
28A
HOUUODLUUNU)
72
51
10
2
16
SI
SO
14
01187
2
26
14
72
217
217
216


216

266
01188
Fibre Faced Wing Valve Assembly
225
Figs. 62 to 66.—Water end of horizontal duplex double acting piston pump.
See next page for list of parts.
Boiler Feed Pumps
415
2. Pump Cylinder.
10.
11. Piston Rod.
14.
15.
16.
18.
25.
26.
Pump Cylinder Removable Liner.
Pump Cylinder Head.
Valve Plate.
Valve Chest Cover.
Frame.
Pump Piston Head.
Pump Piston Follower.
Fibrous Packing.
Plate and Cover Type Cylinder
01187-A-B
50.
Valve Scat.
51. Valve Spring.
Valve.
52.
72. Piston Rod Nut.
77. Cross Head.
78. Cross Head Pin.
Cross Head Brass.
79.
80.
Crank Shaft.
82.
Crank Brass.
85.
Connecting Rod..
27.
28. Inner Packing Ring (Metal).:
28A. Outer Packing Ring (Metal).
29. Piston Rod Gland.
50. Valve Seat.
51.
52.
Pump Cylinder.
Pump Cylinder Removable Liner.
Pump Cylinder Head.
Pump Piston Head.
Pump Piston Follower.
Valve Spring.
Valve.
2.
10.
14.
25.
26.
28. Inner Packing Ring (Metal).
28A. Outer Packing Ring (Metal).
88.
89.
90.
91.
93.
94.
201.
216.
217.
218.
219.
False Head.
Crank Gear.
Pump Pinion Gear.
Pinion Shaft.
Valve Stem.
Valve Guard.
Crank Shaft Bearing.
Liner Securing Stud.
Liner Securing Stud Nut.
Frame Cover.
Piston Rod Oil Flange.
220.
Pinion Shaft Bearing Housing.
220A. Pinion Shaft Bearing Housing (Pulley Side).
Pinion Shaft Bearing Housing Cover.
222.
223.
Crank Shaft Bearing Housing.
225.
234.
247.
253.
Crank Thrust Ring.
254. Pinion Shaft Thrust Ring.
255.
262.
264.
Pump Cylinder Foot.
Pinion Shaft Bearing.
Pinion Shaft Oil Seal.
Side Pot Type Cylinder
01188
Pinion Bearing Outer Race Lock Ring.
Connecting Rod Cap Bolts.
Cradle Head Gasket (Copper).
72.
Piston Rod Nut.
98.
Valve Pot Cover.
216.
Liner Securing Stud.
217. Liner Securing Stud Nut.
Pump Cylinder Foot.
Cradle Head Gasket.
225.
264.
265.
266.
267.
268.
Valve Stem and Washer.
Valve Wing Guide.
Valve Stem Lock Washer.
Valve Stem Lock Nut.
416
Boiler Feed Pumps
Ans. Head on inlet, that is, the water level of the supply is
at a higher elevation than the inlet valve.
What causes a pump to pound and vibrate?
Ans. 1, Air in the liquid; 2, leaky inlet line; 3, leaky packing
on inlet valve chamber cover; 4, leaky packing around plungers
or piston rods; 5, lift too high; 6, excessive speed; 7, vacuum
chamber filled with air; 8, air chamber filled with water.
What causes short stroking?
—
Ans. 1, Pump not properly lubricated; 2, piston rings strike
shoulders worn at ends of cylinder; 3, packing too tight; 4, ex-
cessive cushioning in steam cylinder; 5, excessive head; 6, steam
valves not properly set.
What makes pistons jump at beginning of the stroke?
Ans. Air trapped somewhere in the water end of the pump.
Under what conditions is this most likely to occur?
Ans. On pumps operating with high lift or from allowing the
pump to race when starting.
How should the pump be started?
Ans. Operate slowly for a while with the air vents open.
What is the effect of excessive lift?
Ans. It prevents the pump cylinder filling with water before
the discharge stroke begins.
What causes a piston to strike the cylinder head?
Ans. 1, Improper adjustment of cushion valve; 2, improper
adjustment of lost motion.
Boiler Feed Pumps
417
Ques. Give direction for servicing valve gear when pump
refuses to start.
Ans. Disconnect auxiliary valve stem from the operating
gear without disarranging adjustment of tappet collars. Open
exhaust, inlet and discharge valves and then crack throttle.
Work auxiliary valve by hand; it should work freely by hand.
Should the pump still refuse to start, secure it. Remove valve chest cover,
and examine main valve to see if it has over-ridden or stuck.
If pump cannot now be started a complete overhaul of working parts of
the steam end is necessary to stop steam leakage either in steam piston or
valves, which is the most probable cause of pump not starting.
Ques. What does jerky operation in starting indicate?
Ans. Failure of the water supply to follow water piston.
Ques. How is this trouble corrected?
Ans. See that all inlet line stop or check valves are open and
that the line is clean of obstructions.
Ques. When a feed pump is vapor bound what should be
done?
Ans. Turn a hose on water end.
Ques. If a pump race without increasing its output what is
the cause?
Ans. A leaky plunger, leaky, broken or stuck water valve or
by air leakage.
Ques. What should be done in such case?
418
Boiler Feed Pumps
Ans. Stop pump as soon as practical in order to ascertain
and correct trouble. Should the pump after it has been run-
ning properly, suddenly lose pressure on one stroke, look for a
broken valve at once.
How would you adjust the cushion valve?
Ans. Run the pump without water load, open the cushion
valve until piston strikes the head. If piston strike too hard
adjust the lost motion and do the same if the piston do not
A
B

C
D


nanar
Figs. 67 to 70.-Various forms of drive for power pumps. A, belt single reduc-
tion; B, combined belt and toothed gear double reduction; C, toothed gear,
double reduction; D, chain single reduction.
Boiler Feed Pumps
419
strike. Now place pump under load and close cushion valve
until the piston stops striking cylinder head.
What should be done if pump have no cushion valves?
Ans. Adjust lost motion so there is just enough to permit the
pump to make a full stroke without striking.
What causes steam to blow through the stuffing box at
stroke end?
Ans. Shoulders.
Why?
Ans. When the piston hits these shoulders, they lift the piston
rod in the stuffing box packing, allowing steam to escape.
What makes a pump stop on "dead center"?
Ans. Slide valve worn.
Explain.
Ans. Wear reduces the lap at each end so that when the
valve is in central or neutral position the edge of the valve and
edge of the port are no longer "line and line" but the wear gives
a slight port opening at each end, thus equalizing the pressure
on both sides of the piston, causing it to stop.
Centrifugal Pump Troubles
In most cases what causes faulty operation?
Ans. Faults on the inlet line.
What causes failure to discharge?
Ans. Improper priming.
Explain.
420
Boiler Feed Pumps
1
Ans. If the priming valve be completely opened allowing
water to rush into the pump, it will trap air in the top of the
casing, which will cause a reduction in discharge.
How should the pump be primed?
Ans. Allow the priming water to run slowly and open pet
cock on top of pump.
ADMISSION
MULTI-STAGE
JJUI
SINGLE
ADMISSION
سال
ناک
DISCHARGE
ADMISSION
DOUBLE
ADMISSION
DISCHARGE



Figs. 71 and 72.—Multi-stage impeller assemblies showing path of flow from
admission to discharge. Fig 71, single admission impellers; fig. 72, double
admission impellers.
How can an accumulation of air in the top of pump
casing be avoided?
Ans. Tap in a small pipe with valve from top of casing and
operate with valve "cracked" allowing no more leakage than
necessary.
Boiler Feed Pumps
421
Mention a common cause of reduced capacity.
Ans. Air leaking through the packing of a pump operating
with lift.
What is a good remedy to prevent this?
Ans. Install a lantern ring.
In some cases a grease cup substitutes for the pressure fluid con-
nection to the lantern ring. The lantern ring is kept filled with grease
which works out between the shaft and packing to form an air tight seal..
What attention should be given to inlet screens?
Ans. They should be kept clean.
SINGLE STAGE

P'
BACK TO BACK
SINGLE ADMISSION
FLOW

THRUST
P'
P
가
​P


DOUBLE ADMISSION
Fig. 73.—Natural balancing 1. Single stage with two single admission back:
to back impellers.
Fig. 74.-Natural balancing 2. Single stage with one double admission
impeller.
422
Boiler Feed Pumps
With proper priming, why in some cases does a pump
not deliver full capacity?
Ans. Too much lift.
What sometimes causes a great reduction in capacity?
Ans. Impeller put on backwards by mistake after repairs.
STAGES 3 2
p
FIVE STAGE
ņ
P P'
Lo
P
lat
P
45
•



P



OPPOSING THRUST FORCES
Fig. 75. Natural balancing 3. Five stage with assembly of one double admis-
sion and two pairs of single admission opposing back to back impellers.
What causes a great reduction in both capacity and head?
Ans. Reverse rotation.
What is the effect of worn sealing rings and why?
Ans. When sealing rings between impeller and casing become
Boiler Feed Pumps
423
worn, the capacity is decreased because some of the discharge
flows back into the inlet.
What causes noisy operation?
Ans. 1, Air; 2, cavitation when operating on heads too low
for the design.
Mention a cause of vibration.
Ans. Misalignment which is magnified at high temperatures.
What is the usual cause of packing trouble?
Ans. Too much tightening adjustment.
This tendency, especially among greenhorns is practically universal
and nothing can be done about it—the same goes for belt drive adjust-
ment. Probably more packing has been spoiled by the excessive
tightening of the gland follower by greenhorns than in any other way.
How can trouble by sand lodging in the lantern ring be
avoided?
Ans. Take sealing water from a clean supply and dispose of
any solids that might get into the lantern ring by installing a
drain pipe with valve connecting with the stuffing box below
the ring.
Rotary Pump Troubles
What should be noted about the discharge of a rotary
pump?
Ans. Its discharge is positive, accordingly it will develop ex-
cessive pressure if the discharge line valve be closed; on this
account a safety relief should be provided and set to proper
relieving pressure.
424
Boiler Feed Pumps
What about troubles in general?
Ans. Many of them are similar to troubles with centrifugal
pumps.
What constitutes a major trouble?
Ans. Wear of the rotating parts and casing.
What causes vibration?

Figs. 76 to 78.—Operation of external spur gear pump. Fig. 76, liquid entering
through admission opening; fig. 77, liquid being carried between the gear
teeth toward discharge side; fig. 78, liquid being forced out of pump.
Boiler Feed Pumps
425
#
ADMISSION
Ans. Excessive wear and misalignment.
What precaution should be taken with the inlet and
discharge pipe lines?
Ans. Support these lines so that they do not put a strain on
the pump casing.

CASING
こ
​CRESCENT
SEAL
Fig. 79.—Internal spur gear pump.
DISCHARGE
What reduces capacity?
Ans. Air traps or air leaks.
INTERNAL
GEAR
ROTOR
IDLER
Why?
Ans. Such condition tends to cause internal rubbing.
What is necessary on the inlet line and why?
426
Boiler Feed Pumps
Ans. A strainer to prevent solid materials entering the pump
which would cause damage.
What precaution should be taken with the packing?
Ans. The packing should not be too tight or dry in order to
prevent scoring of the shaft.

IDLER
1111.
illa
1/1
-
ROTOR
CRESCENT
"\\\".
Fig. 80.—Gear type rotary pump. Cutaway view showing casing rotor gears and
crescent in part.
//I.
What other trouble is encountered with tight packing?
Ans. It wastes power, especially on pumps having four
stuffing boxes.
Boiler Feed Pumps
427
How about the speed of rotary pumps?
Ans. They operate at slow speeds and should never be
speeded up more than 10 per cent above rated speed.
•
Give some reasons for noisy operation.
Ans. 1, Too high speed; 2, excessive lift; 3, clogged strainer
or foot valve.
Troubles with
Deep Well Turbine Pumps
Why will the pump not start?
Ans. 1, Faulty motor; 2, fuses or circuit breaker open or
overload relays tripped; 3, pump sand locked; 4, pump frozen;
5, crooked well; 6, faulty thrust bearing; 7, packing too tight.
Why does the pump fail to discharge?
Ans. 1, Lift too great; 2, head too great; 3, pump speed too
low; 4, pump shaft broken; 5, wrong rotation; 6, discharge valve
closed; 7, strainer clogged.
Why is abnormal power sometimes required?
Ans. 1, Speed too high; 2, frequency too high; 3, head too
high; 4, pump binding; 5, pump and motor out of alignment;
6, sand in water; 7, packing too tight; 8, bearing improperly
lubricated; 9, oil too heavy in enclosed pump shaft.
What causes low pressure or capacity?
Ans. 1, Speed too low; 2, clogged strainer; 3, head too great;
4, excessive lift from low level of water supply; 5, worn impeller
clearance; 6, impellers too high in bowls 7, partly closed valve
in discharge line.
428
Boiler Feed Pumps

vonalaszenteli
DEMORALI ONLL.00
BETHLEN.ON
Fig. 81.—Shallow Well Installation.-1. Pump and tank at point of dis-
charge. This installation is satisfactory where the vertical lift C, plus friction
loss in inlet pipe does not exceed lift limits of the pump. If friction
add too much to the total lift, the capacity of the pump may be reduced
considerably and pumps of the reciprocating type may develop a vacuum
hammer. To overcome this difficulty it may be necessary to increase the size
of the inlet pipe in order to reduce the friction loss or move the pump closer
to the source of supply.

kuvat talabigan?
Manuals and
C
A
B
Fig. 82.-Shallow Well Installation 2.-Pump and tank at source of supply.
With this type of installation, no trouble should be encountered on the inlet
side of the pump provided the total lift do. not exceed the lift limit
of the pump. However, a long discharge A, from pump and tank to point of
discharge may set up pipe friction losses sufficient to reduce the flow of water.
Careful consideration must also be given to vertical discharge elevation.
Pressure in the tank must be greater than at point of discharge in order to
force a given amount of water per minute through the discharge pipe and
maintain a minimum pressure on the plumbing fixtures at the higher level.
The extra pressure required is determined by the actual discharge elevation B,
plus discharge pipe friction losses when delivering a given quantity of water
to the house fixtures.
Boiler Feed Pumps
429
Deep Well Pumping System.-Water in a well may stand
near the surface of the ground, but when a pump is placed in
operation the water level may drop considerably, depending
on the vein feeding the well. Dry seasons of the year may
also affect the water level.
C
If this water level drop below 25 feet from the pump inlet valve, a
deep well pump must be installed

A
00
B
Fig. 83.-Shallow Well Installation 3.-Pump at source of supply, tank at
point of discharge. With this type of installation the total lift to pump
must not exceed the lift limit of the pump. The pump will be operating
under higher pressure than will be shown on the pressure gauge in the tank.
This extra pressure is equal to the vertical distance B, plus friction loss in
discharge pipe from pump to tank. Furthermore, pulsations of a reciprocating
pump may cause a momentary excess pressure at each stroke. These pulsations
are partly absorbed by the air chamber usually furnished with this type of
pump, but under these conditions, installing in the discharge line near the
pump, an additional air chamber with check valve is recommended.
Ques. How are reciprocating deep well pumps installed?
Ans. Directly over the well.
Ques. Are deep well jet pumps similarly restricted?
430
Boiler Feed Pumps
Ans. No, they may be placed some distance away from the
well.
Ques. How does a deep well pump work?
Ans. The actual work of pumping water is done by a
cylinder or working barrel, located in the well below the lower
water level.


DROP PIPE
MANHOLE
COVER
NZAJ
SFROST PROOF PIT
AIR
COMPRESSOR
FROST PROOF
SET LENGTH
DEEP WELL
PUMPING HEAD
[SET LENGTH RODS
PLACE DISCHARGE
HEAD BELOW
FROST LINE
TO STORAGE
RELIEF VALVE
AIR CHAMBER
CHECK VALVE
GATE VALVE
PRESSURE
TANK
CHECK VALVE
AND AIR CHAMBER
DROP PIPE
WELL CASING
LOWEST WATER LEVEL
CYLINDER
Figs. 84 and 85..-Deep Well Installation 1.-Reciprocating type with
pumping head with frost proof set. Where it is not possible to have a well con-
veniently located at the house nor to provide a waterproof pit below the frost
line, the method shown here should be used. In such an installation a frost proof
set length may be attached to the pump which puts the discharge head and pip-
ing below the frost level.
Boiler Feed Pumps
431
MANHOLE COVER
VENT
EXOROXINE
TO ELECTRIC SERVICE
PRESSURE
SWITCH
WIRES TO
MOTOR
GATE
VALVE
RELIEF
VALVE
GROUND LEVEL
WELL
CASING
BASEMENT
MANHOLE COVER
DEEP WELL
PUMPING HEAD
PRESSURE GAUGE
AIR CONTROL
STOP AND WASTE VALVE
TO HOUSE LINE
PRESSURE
TANK
DROP PIPE
WELL CASING
LOWEST WATER LEVEL
CYLINDER
CHECK VALVE
Fig. 86.—Arrangement of deep well pump head in frost proof pit at home as indicated in fig. 87.
Fig. 87.-Deep Well Installation 2.-Reciprocating type with pumping head and tank at house. One of
the most satisfactory installations of a deep well water system is with the well located just outside the founda-
tion wall of the house, so that the pump room really becomes a part of the basement, giving easy access to the
pumping head, tank and all controls in any kind of weather. Note that the plunger rod can easily be pulled
up through the manhole for renewal of the cylinder crimps or cup leathers, inspection of valves, etc.


432
Boiler Feed Pumps
Ques. How is this cylinder connected?
Ans. It is connected to the working head or pumping unit
by means of pipe and pump rod.
Ques. What periodic attention is necessary for deep well
pumps?
MANHOLE COVER
VENT-
WIRES TO
MOTOR
TO HOUSE
LINE
RELIEF
VALVE
TO ELECTRIC
SERVICE
GROUND LEVEL
DEEP WELL
PUMPING HEAD
PRESSURE SWITCH
L-AIR CONTROL
TANK DRAIN
CHECK AND WASTE
PRESSURE
TANK
DROP PIPE
WELL CASING
LOWEST WATER LEVEL
WELL CASING UNION CIll CK
GATE VALVE
Fig. 88. -Deep Well Installation 3.-Reciprocating type with pumping
head in pit with horizontal tank. Often the well is somewhat removed from
the house or point of discharge, making it impossible to build a pump room
connecting the basement. Under such conditions a frost-proof pit may be
arranged to set the pumping head and motor below frost level. A horizontal
type of tank may be buried in the ground with only the end extending intc
the pit for attaching gauges, controls, etc. thus saving space.
CYLINDER
Ans. They require occasional renewal of the piston leathers
and valve facings.
Ques. How are they constructed to facilitate this?
Ans. The cylinder top is open from which the piston and
lower valve may be withdrawn without removing the cylinder
from the well or disturbing the pipe connections. The accom-
panying illustrations, figs. 84 to 88, show various deep well
installations.
+


Feed Water Heaters
433
CHAPTER 24
•
Feed Water Heaters
What is a feeder water heater?
Ans. An apparatus for raising the temperature of boiler feed
water by abstracting some of the heat from: 1, exhaust steam;
or 2, from the hot gases of combustion.
How are these distinguished by name?
Ans. They are called primary feed water heaters and sec-
ondary feed water heaters, according as source of heat is exhaust
steam or the hot gases of combustion respectively.
What name is generally given to a secondary feed water
heater?
Ans. Economizer.
Give a further classification of feed water heaters.
Ans. They may be further classed:
1. With respect to provision for getting rid of the air, as:
a. Deaerating.
b. Non-deaerating.
434
Feed Water Heaters
OPEN
L
話
​CLOSED
(STEAM TUBE)
о
O
O
O
FEED INLET
SCALE
PRECIPROCATING
PANS
EXHAUST INLET
FEED OUTLET
CLOSED
(WATER TUBE)
L


FEED OUTLET
Est
STEAM INLET
о
O
STEAM TUBE
FEED INLET
STEAM OUTLET
о
о
O
EXHAUST INLET
FEED OUTLET
WATER TUBE
FEED INLET
EXHAUST OUTLET `

Figs. 1 to 3.-Elementary diagrams
showing three types of feed water
heaters. Fig. 1, open; fig. 2, closed,
water tube, fig. 3, closed steam
tube.
Feed Water Heaters
435
2. With respect to hook up and other features, as:
a. Open or semi-closed system.
b. Single stage.
c. Multi-stage.
d. Steam tube.
e. Metering.
What is the object of heating the feed water?
Ans. 1. To save some of the heat going to waste in the
exhaust steam; and 2, in some cases to purify the feed water,
that is, to eliminate scale forming substances by precipitation.
Why do you say "to save some of the heat ..."?
Ans. It is impossible to save all of the heat.
Why?
Ans. In any practical construction there is a temperature
difference, that is, the exhaust steam leaves the heater at a
higher temperature than the final temperature of the water.
How would you determine the saving by heating the
feed water?
Ans. The following example will illustrate the method.
Example. — If the temperature of the feed water be 60° Fahr. before
entering the feed water heater, and the heater raise its temperature to
210°, what is the saving with boiler pressure at 99.3 lbs. gauge pressure?
Total heat in 1 lb. of steam at 99.3 lbs. abs...
Total heat in 1 lb. of feed water entering the boiler at 60°.
Heat required to form 1 lb. of steam..
Total heat in water leaving the feed water heater
at 210° = 177.5 B.t.u. (approx.)
Heat saved by heating the feed water from 60°
to 210° Fahr.
= 177.5 28.08
-
*
149.42 B.t.u.
1188.7 B.t.u.
28.08
1160.62 B.t.u.

436
Feed Water Heaters
Percentage of saving = 149.42 1160.62 = .121.
That is 12.1 per cent which is equal to 1 per cent for each 149.42 ÷
12.1 12.3 degrees that the temperature is raised by the heater.
=
Is a saving of fuel realized where the feed water is heated
by an injector or live steam purifier and why?
STUJA
Ans. No, because both devices draw from the boiler the heat
which is imparted to the feed water.
on quisit
ben1500
OWEN 2012
17
V477
aland
ust votant
blow Roll
KEE
122
lot
Fig. 4.-Sectional view of an open feed water heater showing the water flowing
over the heating trays as it comes into direct contact with the steam. Note the
float for operating the regulating valve and in addition the built in overflow
trap.

Feed Water Heaters
437
Name two general types of feed water heater.
Ans. 1, Open; and 2, closed.
What is an open heater?
Ans. One in which the exhaust steam and feed water are
brought into intimate actual contact by spraying the water
through the steam.
What are the advantages of the open heater?
Ans. It is more efficient than the closed heater, but the
Fig. 5.-Open feed water heater developed for plants where the feed water is
extremely bad, the water containing mud, silt, and bicarbonates of calcium
and magnesium. These impurities form scale on the pans of this type of heater
and clogging of feed lines and boiler tubes, which causes considerable expense,
is thereby prevented. The heating pans are of single trough shape construction
made of thin sheet steel and can easily and readily be removed from the heater
for cleaning.

438
Feed Water Heaters
principal advantage is the separation of scale forming sub-
stances from the feed water by precipitation.
What is the arrangement for separating the scale form-
ing substances called? da odabirw mismo an
Ans. A purifier, that is, the purifier is a part of the open
heater.
Saliste en
guouts
BAW
Fig. 6.-Clean steel pan.
Fig. 7.-Lime coated steel pan.
What is the disadvantage of the open heater?
Ans. Since the condensate goes into the boiler along with the
feed water, the latter is contaminated with oil in the exhaust
steam.
buin
wend
What provision is made to get rid of the oil?
bin loade
Ans. Some form of oil extractor must be used.
OUW
ppolo Coo
ydude
int ip-obe
bom
gmno Sat

Feed Water Heaters
439
Does an open heater free feed water from all of the
impurities?
Ans. No.
Where is the open heater located with respect to the
feed pump?
Ans. Always on the inlet side.
Why?
吃饱
​VENT
Fig. 8.-Float and connections.
Ans. Because it is a low pressure heater, and is placed at a
sufficient elevation to prevent the formation of steam at the
inlet to pump.
No Vie mit sie logico
7099
How high should the heater be placed?
Explain?
Ans. The heater is located higher than the pump so as to
operate under negative lift, otherwise it would be subject to
partial vacuum and the hot water would flash into steam.
VOC
em
fucin

440
Feed Water Heaters
Ans. The elevation above pump depends upon the tempera-
ture of the water. Usually 12 ft. negative lift is sufficient for
open heaters.
What happens if the feed pump become steam bound?
Ans. It will race and so may be damaged.
garug bool
Inions do ewth an
HOPPES
Fol
Fig. 9.-V notch, meter recorder and integrator forming attachments of a well
known open feed water heater. The V notch water meter consists of a tank con-
taining a V notch and a cabinet attached to the tank as shown. Inside the
cabinet is a copper vessel, called the weighing vessel. This vessel is suspended
by a coil spring and is connected to the tank by flexible connection in such a
manner that the water in the vessel will be in equilibrium with the water behind
the weir. As the water enters the tank and rises in the compartment behind the
V notch, it also rises inside the weighing vessel. This vessel is designed to con-
tain just enough water at each unit of height to draw down the spring in exact
ratio to the rate of flow. The pen and recorder are directly attached to it with-
out the use of cams or other motion changing devices.

Feed Water Heaters
441
How about the steam supply to open heaters?
Ans. It is seldom over 3 to 5 lbs. per sq. in. gauge pressure.
of Vidiman vele
What provision is made?
Ans. The heater shell is usually vented to atmosphere
through a small line.
hot lade om
www
VENT
CONDENSER
SECTION
DEAERATING
SECTION
STORAGE
SECTION
Fig. 10.-Marine type deaerating feed water heater. If a glass of cold water
be placed in a warm room, bubbles will form on the inside of the glass. These
bubbles are air, and they form because the water, as it becomes warmer, will
hold less air. This smaller amount of air at hotter temperature will do more
damage than the greater quantities at lower temperatures as witness the fact
that steel hot water pipes rust much faster than steel cold water pipes. It follows,
then, that a very small amount of air, in water which w.ll be heated to the tem-
peratures existing in a high pressure boiler, will be very destructive indeed.
Consequently if damage to boiler and piping is to be prevented, all of the air
must be removed from the water before it enters the boiler. Accordingly, the
deaerating heater is designed to heat feed water and, at the same time, remove
practically all of the air combined in the water, i.e. deaerate it.
442
Feed Water Heaters
MAKE UP FEED
MAIN AIR EJECTOR
INTERÊ AFTER
CONDENSER
MAIN
CONDENSER
MAIN
CONDENSATE PUMP
OVERFLOW TO
RESERVE FEED
TANKS
AUX AIR EJECTOR
INTER & AFTER
CONDENSER
AUXILIARY
CONDENSER
SURGE
TANK
'AUX CONDENSATE
PUMP
ATMOSPHERIC DRAINS
TO FRESH WATER
COLLECTING TANK
IOLB. GAUGE
AUX EXHAUST AND
BLEEDER STEAM
OVERFLOW
TO BILGE
Sk
ras
FEEDWATER
HEATER
DRAIN COOLER
2
FEED PUMP
STEAM DRAINS
UNDER PRESSURE
FEED WATER
HEATER
TO BOILERS
THRU ECONOMIZERS
Fig. 11.-Open or semi-closed feed water system for
800 shaft h.p. oil fired water tube boilers generat-
ing steam at 400 lb. sq. in. gauge and 750°F.B.t.u.
shaft h.p. approx. 11,509. Oxygen content in feed
water normally .2 to .4 cc/1.

Feed Water Heaters
443
What is the maximum temperature obtainable?
Ans. Slightly over 212° Fahr.
What safety device is provided.
Ans. The shell is protected by an atmospheric relief valve
set at the maximum pressure-usually 15 lbs. per sq. in.
What is a closed heater?
Ans. One in which the exhaust steam and feed water are
separated by a metal surface through which the heat must pass.
What is the advantage of this arrangement?
Ans. No oil can enter the boiler.
What is the disadvantage?
Ans. The heater is not as efficient as the open heater.
Why?
Ans. Because the steam does not come into actual contact
with the water, but has to be transmitted through the metal
forming the heating surface.
What precaution should be taken in the case of closed
heater?
Ans. A closed heater should not be used unless the feed water
be reasonably free from scale forming substances.
Why?
Ans. The metal forming the heating substance is subject to
deposit of oil on the steam side and scale on the water side.
Both being good insulators decrease the efficiency of the heater.
444
Feed Water Heaters
MAKE UP
FEED
MAIN
CONDENSER
MAIN AIR
EJECTOR
INTER. & AFTER
CONDENSERS
MAIN
CONDENSATE PUMP
10 LB. GAUGE
AUX EXHAUST
AND BLEEDER
STEAM
AUX CONDENSER
Aux Air EJECTORS
VENT & AFTER
CONDENSERS
AUX CONDENSATE
PUMP
ATMOSPHEric DrainS
TO FRESH WATER COLLECTING
TANK
OVERFLOW
TO RESERVE
FEED TANKS
COCHRANE
DEAERATOR
STEAM DRAINS
UNDER PRESSURE
D
BOILER FEED
PUMP
TO BOILER
Fig. 12.-Single stage feed system with direct contact
deaerating heater. Zero oxygen in feed water, 8000
shaft h.p. Oil fired water tube boilers generating
steam at 400 lb. sq. in. gauge and 750° F. Approxi-
mate B.t.u. shaft horse power 11,488.
}

Feed Water Heaters
445
Name two types of closed heater?
Ans. 1, The water tube heater; and 2, the steam tube heater.
Describe construction of the water tube heater?
Ans. A typical heater consists of two or more coils (depending
on size) connected in parallel and placed within a casing which
is provided with inlet and outlet for the exhaust. The ends of
the coils are spaced so that ample area is provided for the
flange of the exhaust without undue back pressure.
Describe construction of the steam tube heater.
Ans. A typical heater has a shell of heavy steel plate which
contains the water to be heated and the steam tubes. Each
tube is U shape, both ends being expanded into a tube head
bolted to the lower part of the shell. The head has a partition
so that steam enters one end of each tube and leaves at the
other end.
What is the application of this heater?
Ans. It is used to a considerable extent in plants where the
inequalities of service compel an irregular feeding of the boilers,
or where the exhaust steam supply is intermittent. In such
cases the large volume of water held in storage is essential to
absorb the heat from the exhaust steam. Moreover impurities
tend to settle to the bottom where they may be drawn off from
time to time.
Does the feed water from a heater enter the boiler at
the same temperature as on leaving the heater?
Ans. No, there is a loss in temperature.
Why?
Ans. It is due to transmission loss.
446
Feed Water Heaters
MAKE UP
FEED
MAIN AIR EJECTOR
INTER & AFTER
CONDENSERS
MAIN
CONDENSER
MAIN
CONDENSATE PUMP-
fot
AUX
CONDENSER
AUX. CONDENSATE
PUMP
AUX,AIR EJECTORS
VENT & AFTER
CONDENSERS
10LB. GAUGE
·AUX EXHAUST & BLEEDER
STEAM
LOW PRESSURE
BLEED
ATMOSPHERIC ŪRAINS
TO FRESH WATER
COLLECTING TANK
FEED WATER
HEATER
FEED WATER HEATER
DRAIN COOL ER
OVERFLOW TO
RESERVE FEED
TANKS
COCHRANE
DESERATOR
TRAP
HIGH PRESSURE
BLEED
FEED WATER
HEATER
Di
FEED PUMP
STEAM DRAINS
UNDER PRESSURE
TO
BOILER
Fig. 13. Multi stage feed system with direct contact deaerating heater. Zero oxygen in feed water. 8000 shaft
h.p. Oil fired water tube boilers generating steam at 400 lb. sq. in. gauge and 750° F. Approximate B.t.u.
shaft horse power 10,872.

Feed Water Heaters
447
How can this loss be reduced to a minimum?
Ans. By having the piping short, direct and well covered
with best insulating material.
What mistake is usually made in buying heaters?
Ans. Buying a heater too small in the mistaken idea of
saving money.
Where should the feed water enter a closed heater?
Ans. At the top where the exhaust steam is leaving heater.
Why?
Ans. Because if located otherwise the cold water coming in
contact with the highest temperature of steam would cause the
tubes to become brittle or crystallized.
Of what material are the coils made?
Ans. Brass or copper.
How would you test heater for a leaky coil?
Ans. Stop engine, partially close valve on the discharge near
the boiler and start pump. Open drip; leaking tube or tubes
will be indicated by water running out of drip.
How would you know heater was leaking with plant in
operation?
Ans. Leak would be indicated by pump running faster and
extra amount of spray coming out of the exhaust.
What should be installed at the bottom of a closed
heater?
Ans. A trap.
448
Feed Water Heaters

1000* THE
180°F
Surface
Condenser
28*Vac.
671,050 IN
101.2°F
Condensate
Pump
L.P.Turbine
1000/Hr.
To Ejector
raps
15 abs
70,400/Hr.
180.2
70
;
6000/Hr.
40ªabs.
WA
105.77
Ejector Inter
& After Condensers
89,550 Hr.
120 abs.
210.2F
Drain
Cooler
Trap
765,600 Hr.
275 #abs.
#2Direct Contact
& Storage Heater
671,050 #Hr.
205.2°F
#I LP
Heater
Make-up
Evaporator
25.000 HK
38 abs
3/17.45
Trap
9.000 THE
2642F*
337.4°F
*29,750*(Hr.
59.800 Hr.
25.000 Hr.
70°F
Δ
Trap 2017 OF
332.4°F
H.P\ Turbine
STACO JIHE
Trap
833.000 Hr
1200 Ga-900%
859,000*/Hr. to Bailer
399.7°F.
#3 HP.
Heater
#4H.P.
Heater
1st Stage
Boiler Feeа
Pump
2nd Stage
Boiler Feed
Pump
Fig. 14.-Typical regenerative feed heating diagram. Three closed type heaters, a direct contact heater, a
drain cooler, and an evaporator result in a calculated reduction of heat consumption of approximately 12.6%.
Feed Water Heaters
449
Should condensate from trap be returned to boiler and
why?
Ans. No, because it contains too much oil.
How do you clean scale from the tubes?
Ans. With sal soda. Use about 10 lbs. per week for each
75 h.p. of boiler.
How is it applied?
Ans. Feed it into the inlet of the pump.
What provision in the piping should be made so that a
heater may be repaired?
Ans. A by pass for the exhaust.
NOTE. The corrosion problem is completely answered by a deaerating unit
which when operated at a pressure above atmospheric, delivers oxygen-free water
and has the additional advantage of supplanting the conventional feed tank and
one of the feed water heaters.
1
NOTE.—The open surge tank and steam blanketed or semi-closed systems
very frequently do not give satisfactory protection against corrosion. The oxygen
content of the feed water passing through these systems is generally in the neigh-
borhood of .1 to .4 ec per liter. The closed system, if maintained absolutely tight
to prevent air infiltration, would theoretically give better results; however, the
oxygen content of water in such systems has been found to be as high as .2 cc per
liter. The feed water with this oxygen content is not good enough for the modern
boiler since considerable corrosion will occur as long as there is any trace of oxygen
in the water.
NOTE. Not only do closed feed systems fail to give the highest degree of
freedom from oxygen but they are also slow and inefficient in removing the oxygen
from the feed system when starting up after shut down. Furthermore, in such
systems, where the main condenser is used for removal of oxygen from the water,
efficiency in removal will be less in proportion as the temperature of the water
leaving the hot well is below the exact steam temperature corresponding to the
vacuum. Whenever this temperature is lower than the vacuum temperature, com
plete removal of oxygen is impossible according to the law of solubility.

450
Feed Water Heaters
0
Fig. 15.-Typical deaerating metering heater cylindrical cast iron machine
joint construction. Regardless of type, a feed water heater should be designed
to meet the individual requirements of each user. Space limitations, materials
of construction and operating conditions widely affect the design of feed
water heaters.
Economizers
451
CHAPTER 25
Economizers
What is an economizer?
Ans. A second stage or secondary feed water heater which
utilizes the hot gases leaving the boiler instead of exhaust
steam as in a primary feed water heater.
What distinction should be made between the terms
feed water heater and economizer?
Ans. They are entirely different heating devices. The word
feed water heater is always applied to the first stage heater
using exhaust steam as the heating medium, whereas the
economizer uses the hot gases of combustion as the heating
medium.
Of what does an economizer consist?
Ans. It consists of a number of tubes through which the feed
pump discharges feed water to the boiler.
Where is an economizer of the independent type located?
Ans. Between the boiler setting and the chimney.
452
Economizers

܀
L
I-BEAM
SUPPORTING HEADERS
ASBESTOS GASKETS
STOP
Bl
Bl
BA
HAND HOLE COVER
BA
BEAD SEAL
S
GASKET SEATS
BBAA
TUBE SUPPORTS

GASKET
Figs. 1 to 5.-Header type economizer construction. The economizer consists of
groups of rectangular seamless steel headers connected by seamless steel tubes.
Each tube has one U-bend. Separate return bends are also used. Two or two and
one-half inch O.D. tubes are used. One end of each tube is expanded into the
upper tube hole of the header and the other end is expanded into the lower hole
of the header immediately above. The tubes are spaced parallel and with a
lane of sufficient width between alternate rows of tubes to permit tube removal.
The tubes from the top header are normally connected to the number three
Economizers
453
What was the typical construction formerly used?
Ans. It consisted of a series of cast iron tubes made up in
sections connected at the ends and placed in a brick chamber
through which the gases pass from the boiler to the chimney
or fan. Feed water is forced through the tubes while the hot
gases circulate around them.
What device was provided to keep the tubes clean?
Ans. For removing soot from the tubes, scrapers were pro-
vided, arranged to move slowly up and down each tube driven
by an engine.
Why were the tubes made of cast iron?
Ans. Because cast iron resists corrosion longer than steel
when exposed to gases of combustion at comparatively low
temperatures.
What was necessary with very high pressure boilers when
cast iron tubes were used?
Ans. A secondary feed pump was used to relieve the tube
from excessive pressure.
*
Figs. 1 to 5.-Text continued.
drum. Hand hole covers, each of which serves four tube holes and is held in
place by a single integral forged stud and nut, are drop forgings. Gasket seats
in headers are carefully machined. Armored gaskets are used. Headers are
installed in groups of the desirable number with enlarged U-tubes connecting
the groups. This construction permits intermediate header supports, permits free
expansion of each group and ready access to the economizer. Headers are
supported on structural members with separate supports for each group of
headers. Headers are held in place at each end by a channel or other structural
members. This construction permits free expansion vertically and horizontally.
The U-bends are supported by H-columns, one flange of which is specially
notched to hold the upper loop of the U-bend. The entire economizer is en-
closed in a panelled steel insulated casing properly constructed and reinforced
to assure gas tightness at all ratings. The ends are equipped with gas tight
hinged doors to give quick and easy access to the economizer.

454
Economizers
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Figs. 6 to 8.-Marine header stud type economizer
construction. The stud tube economizer also called ex-
tended surface type is designed to produce maximum heat
absorption with minimum resistance to the flow of gases. The
studs are welded to the tubes to insure high thermal conductivity be-
tween tubes and extended surface. Since continuous loop welded tubes
are used, rolled joints are reduced to the minimum. In the bare tube econo-
mizers, whether of the single loop tube or continuous loop tube type, the ends
of the tubes are expanded into the headers and may also be welded. By the use of small
tubes and a single cross flow of gases, all ledges and soot pockets are eliminated, and ex-
ternal cleaning of the tubes can be readily accomplished.
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200WL

Economizers
455
What is the prevailing practice as to tubes and why?
Ans. Steel tubes are used, made practical by advances in
oxygen control, thus cast iron pipes are not so common as
formerly.
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ad nes Jedi 9ostua goieod to moms of
eges
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FIRLEITT
sed
timil 16d/
e poi bollemei
Fig. 9.-Return bend continuous tube type economizer. It consists of intercon-
nected sections of horizontal, seamless steel tubes so disposed across the path
of the hot gases as to assure a maximum rate of heat transfer with minimum
resistance to the flow of gases and water. Noteworthy features of design in-
clude: minimum return-bend fittings, absence of handholes, ample allowance
for expansion and gas tightness under all conditions of operation. The direct
connection of the elements to the boiler drum minimizes the pressure drop and
eliminates the necessity for a water relief valve.
456
Economizers
What degree of heat is available for heating feed water
by economizers?
Ans. The temperature of the hot gases escaping up the
chimney from 500° to 700° Fahr., which represents a con-
siderable margin for the second stage heating of the feed water.
What limits the amount of heating surface that can be
installed in an economizer?
Ans. It is limited by the final temperature at the exit of the
economizer.

GAS
FLOW
ECONOMIZER OUTLETS TO BOILER DRUM
ECONOMIZER INLET
[0]
I
Fig. 10.-Return bend loop tube type economizer. The economizers shown in
figs. 9 and 10 have been built in sizes having 357 to over 31,200 square
feet of heating surface, and for working pressures up to 1400 lbs. per sq. in.
GAS
FLOW
AEROPLETY
Economizers
457
Why?
Ans. If the gas temperature be cooled below the dew point
"sweating" will result. Sulphur in the soot then unites with
moisture to produce a sulphurous acid which quickly corrodes
steel construction between the economizer and the stack.
Mention a late practice in boiler construction.
Ans. Some manufacturers are building their boilers with an

Fig. 11.-Marine return bend with bifurcations type economizer. The illustration
shows bifurcations, cleanout ends, gas sealing collars with self locking crown
spring, tube sheet and split fin tube heating elements.
integral bank of feed water heating tubes forming part of the
boiler and inside the boiler casing and in the last gas pass of
the boiler.
This is generally called a feed water heater because it is placed
within the boiler casing. Strictly speaking, the term economizer means
*
458
Economizers
៩
a feed water heating device that not only employs the hot gases as the
heating medium, but is located outside of the boiler casing, that is, it
is not a part of the boiler.
Upon what does the economy of an economizer depend?
Ans. The economic result from using an economizer when
the draught is sufficient depends upon the normal temperature
of the flue gases escaping from the boiler and of the feed water
supplied to the economizer.
How is the gain calculated?
Ans. As follows:
Gain in per cent
in which
T= heat units in 1 lb. of feed water above 32° Fahr. after
heating.
t = heat units in 1 lb. of feed water above 32° Fahr. before
heating.
100 (T-t)
H-t
H = heat units in 1 lb. of steam of boiler pressure above 32°.
Example. If the temperature of the feed water be raised from
190° to 310° Fahr. by an economizer and gauge steam pressure is
150 lbs. what is the gain?
Substituting
Gain
In the formula just given and the steam tables (page 47).
T=280 B.t.u.
t=161 B.t.u.
H=1195 B.t.u. (approx.)
100(280—161)__100×119
1195-161
1034
}
= 11.5 per cent
Feed Water Deaeration
459
CHAPTER 26
Feed Water Deaeration
For what was the word deaeration coined?
Ans. To describe a particular stage in boiler feed water
conditioning.
That answer gives no information, explain specifically
what is deaeration?
Ans. It is the process of separating and getting rid of air
and oxygen in feed water.
Why should these gases be removed?
Ans. Because oxygen causes corrosion in boilers.
How does the oxygen and air get into the water?
Ans. Both oxygen and air are soluble in water.
Upon what does the solubility depend?
Ans. It depends upon temperature and pressure.
Explain the relation.
Ans. Maximum solubility is at low temperatures and high
pressures and minimum solubility is at high temperatures and
decreased pressures.
460
Feed Water Deaeration
Describe the essentials of deaeration.
Ans. The process is to produce a condition which will sepa-
rate entrained air and air in solution from the water, and get
rid of the air before it can get back into the water again.
How can the air be separated from the water?
Ans. By heating the water and flashing it into a region of
pressure with a saturated temperature less than that to which
the water has been heated.
By what other method can this be accomplished?
Ans. By heating in a direct contact heater which is propor-
tioned to heat the water to the saturated temperature at the
pressure being maintained.
What is the next step?
Ans. To provide an oxygen free steam "atmosphere" above
the water.
1300#
KAKASA *
What will happen if the bubbles of oxygen on separating
be left in this steam atmosphere?
Ans. If left in this "atmosphere" over the water surface, they
will be re-absorbed due to their solubility.
How are they removed?
Ans. By passing oxygen free steam over the surface of the
water.
Describe the process more in detail.
Ans. The oxygen is concentrated at some point where it can
be removed.
Feed Water Deaeration
461
Is this removal steam vented to the atmosphere and
wasted?
Ans. No.
How is waste avoided?
Ans. It is used as the medium for heating the water.
How does the steam flow in the deaerating apparatus?
Ans. In counter current flow units, this steam passes into
the heating section from the deaerating section where the con-
centration of gases is increased by condensation of the con-
densable steam. Then finally a small percentage is used as a
carrier for the gases and is taken into the vent chamber where
the concentration is completed by the final condensation of the
condensable portion, and the gases then expelled to the at-
mosphere.
Describe the flow in the parallel flow type.
Ans. In this type the steam passes directly from the de-
aerating section of the unit to the vent condenser, since it has
previously passed through the heating section.
Describe the original flash type deaerator.
Ans. It had separate heating and deaerating shells and the
water from the heating chamber was passed into the flash
chamber which maintained a lower pressure. Explosive boiling
liberated the gases and formed steam to carry the gases to the
vent condenser.
What is the application of this type?
NOTE. See Chapter 27 for deaerating feed water heaters, various hook ups, etc

462
Feed Water Deaeration
Ans. It has a definite application where low temperature
deaerated water is needed and where this temperature difference
is not detrimental to the heat cycle.
Describe a recent development of the marine type de-
aerator used in merchant marine and Navy plants aboard
ships.
Saulinungs
oll
Sho
กว่า
emorisont
gore
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downl
un W
Fig. 1.-One of several atomizing type marine deaerating heaters built for the
Maritime Commission's C-2 ships. A float operated diversion valve shunts
entering water when supply exceeds boiler demand.
Feed Water Deaeration
463
Ans. This type of equipment uses a battery of spray nozzles
for spraying the water into the steam "atmosphere" in the heat-
ing section after which the water is collected and put through a
deaeration nozzle where the steam and water are intimately
mixed and broken up.
Average Specific Penetration in Inches per Year
per C.C. Oxygen per Liter
How is the steam brought into the unit?
Ans. Through the deaerator nozzle, thence into the heating
section and finally a small percentage is taken into the vent
condenser.

0035
0030
00:5
0.020
Distilled Water plus CO₂
45 50 55
Pittsburgh, Sept 1923
0.0
Pittsburgh, May 1923
Distilled Water
as 70
New York
75
o Chicago
80 85 90 95
pH Value of Water
Fig. 2.-Relation of pH value (alkalinity) to corrosiveness on basis of equal
dissolved oxygen content.
What is the feature of this equipment?
Ans. It is developed to take care of the roll and pitch of a
vessel which eliminates consideration of a tray type.
-
464
Feed Water Deaeration
What should be noted about deaerators?
Ans. A deficiency of steam will defeat the purpose of a de-
aerator in heating and gas removal.
Mention one item of importance.
Ans. The problem of the inlet valve is one which causes more
trouble than any other single item involved in a deaerator.

16吋
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Gage Pressure Pounds
pressures.
12
20
10
26
Aches Mercury
32 50 70 90 110 130 150 170 190 210 230 250
Temperature, Degrees Fahrenheit
Fig. 3.-Solubility of oxygen in water exposed to ordinary atmosphere at given
Careful consideration of quantity and pressure should be made.
before actual installation.
Describe in detail the deaerating cycle employed in a well
known deaerator which represents latest practice for
marine power plants.
Ans. The feed water enters and passes through the vent
Feed Water Deaeration
465
condenser to the pre-heater from which it is discharged with prac-
tically uniform velocity at all loads into an atmosphere of steam.
This initial spraying heats the water almost to the steam tem-
perature and at the same time removes much of the dissolved
oxygen.
The pre-heated and partially deaerated water is collected and dis-
tributed uniformly over the atomizer where the incoming steam breaks
the water down into a fine mist, thereby exposing a large aggregate
liquid surface. The flow of steam agitates and scrubs the water surfaces
and carries away the liberated oxygen and other gases. The deaerated
water falls into the storage compartment and the steam and liberated
gases are delivered to the pre-heater where nearly all of the steam is
condensed in the initial heating of the water. Some of the steam, how-
ever, continually flows to the vent condenser carrying with it the
liberated gases, which may then be discharged to the atmosphere.
How should the deaerator be located?
Ans. Ordinarily the design can be elevated sufficiently to give
the head required on the inlet of the boiler feed pump. When the
available head room is too limited to permit this, a low head
booster pump is used.
Describe the pre-heater.
Ans. It is of the direct contact type, using spray nozzles of
non-ferrous material, designed for operation under low water
pressures. They spray the water outward and upward in contact
with the steam which is supplied by the atomizer at practically
constant differential pressure, in a conical jet.
Describe the atomizer.
Ans. It consists of a bronze valve ordinarily in the form of
an inverted cap seating against the end of the downwardly pro-
jecting steam pipe, and is held to its seat by external spring
loading. The incoming steam discharges through the atomizer
at practically constant differential pressure, in a conical jet.
466
Feed Water Deaeration
With a differential steam pressure of 1½ lb. per sq. in., the velocity
of the steam jet exceeds 300 ft. per second. Its kinetic energy is em-
ployed to atomize the pre-heated water, creating a fog or mist, thus
exposing a maximum water surface for liberation and separation of
gas bubbles. The steam and liberated gases flow upward to the pre-
heater and the deaerated water then falls to the storage space.
Feed Water Treatment
467
CHAPTER 27
Feed Water Treatment
The importance of correct boiler water treatment and control
in the steam plant of to-day cannot be overlooked if the best
operating efficiency of the steam making units is to be expected.
It is not necessary to tolerate "fair" results, when a properly
balanced treatment used in accordance with boiler water tests,
will provide virtually scale free heating surfaces.
In feed water treatment, what is essential?
Ans. That the treatment used be properly selected to meet
the conditions as shown by the feed water analysis.
What is the important consideration in selecting the
treatment?
Ans. It is important that the boiler and operating conditions.
be taken into consideration, since operating pressure, rate of
steaming and other factors, influence the selection of reagents.
which can be used to best advantage, in order to assure continuous
steam production and extended periods of boiler operation.
As far as the condition of the boiler water is concerned, it is essential
that the feed water treatment used be properly adjusted to meet the
requirements of the plant under consideration. It is of prime im-
portance that scale deposits be prevented forming on the heating
468
Feed Water Treatment
surfaces, and at the same time, it is necessary that heater coils and
feed lines also be maintained in good condition, from the standpoint
of lime scale deposits.
It is important that boiler water concentrations be controlled by
means of proper tests; that the treatment be adjusted so as to avoid
the production of excessive alkalinity and that condensers be main-
tained tight to avoid excessive chloride or salt concentration.
What are the tests most commonly used and required
for the average plant?
Ans. They are:
1. Phenolphthalein alkalinity.
2. Methyl orange alkalinity.
3. Chlorides (Salt).
4. Hardness..
P.
In some plants it may also be necessary to make additional
tests (depending upon operating conditions, water supply, etc.)
such as:
•
M
с
H
5. Total sulphates.
SO 4
O2
6. Dissolved oxygen
7. Free carbon dioxide
CO2
8. Hydrogen ion concentration... pH Value
·
How are these tests conveniently made?
Ans. Compact equipment is available for the determination
if any, or all, of these tests.
How are the test solutions generally standardized?
Ans. They are standardized to be used with a 58.3. cubic
NOTE. The use of water treatment without the necessary testing equipment
and knowledge of correct interpretation to determine dosage and blow down
procedure, might be compared with the operation of a steam plant without
adequate meters, thermometers and gauges.
Feed Water Treatment
469
centimeter sample of water, and the burette read direct in
grains per gallon, of the item sought.
In the average plant where alkalinity, chloride (salt) and hardness
tests are made on boiler water samples, definite information is obtained
as to the condition of the water. at any time, from the standpoint of
treatment adjustment and concentration. It is advisable to adjust the
treatment dosage so that the boiler water hardness is reduced to zero.
This condition insures absolutely no scale formation.
What should be known about the boiler water?
Ans. It is advantageous to know the amount of excess soda
ash and caustic soda in the boiler water.
How can this be calculated?
Ans. Calculation may be made from the P, M and H read-
ings, as follows:
M minus H = A
66
2P
M=B
B=C
A
(6
(Excess alkalinity)
(Caustic soda)
(Soda ash)
All of these results are in terms of calcium carbonate (limestone)
and therefore, factors must be used if results in terms of soda ash
and caustic be required.
To convert calcium carbonate (limestone) to caustic soda, multiply
by 0.8. To convert calcium carbonate (limestone) to soda ash, multiply
by 1.06. The chloride determination gives valuable information re-
garding boiler water concentration.
What does the chloride concentration indicate?
Ans. It serves as an index to total concentration, and blow
down requirements can be based on this test.
For example, the number of concentrations in the boiler water at
any time can be determined by dividing the boiler water chloride by
the feed chloride and per cent blow down can be approximately cal-
culated by dividing the "times" concentration into 100.
470
Feed Water Treatment
Upon what does the foaming characteristic of a boiler
depend?
Ans. It depends upon variables, such as the rate of steaming,
design of boiler and concentration of the water.
It is apparent that the chloride determination will give valuable
information with respect to blow down requirements.
What should be noted about blow down regulation?
Ans. It is usually necessary to determine the maximum con-
centration which can be carried in any boiler plant, and blow
down must be regulated accordingly.
What usually causes corrosion in marine boilers?
Ans. In practically every case it is caused by low alkalinity
of the boiler water and the presence of dissolved oxygen.
How can dissolved gases be eliminated to advantage?
Ans. By maintaining a high temperature in the hot well and
open heaters.
However, it may be necessary to use a treatment which will absort
residual oxygen in the boiler water. It is also advisable, in most cases,
to maintain the P alkalinity between 8 and 10 grains per gallon.
Testing
The following instructions give all the information necessary
to make the tests just mentioned.
Hardness Test
Procedure. First of all standardize the soap solution with
pure, distilled water. Measure out a full sample of distilled

Feed Water Treatment
471.
Fig. 1.-Typical kit for making boiler feed water tests.
472
Feed Water Treatment
water (58.3 c.c.). Place the measured sample into the glass
stoppered shaker bottle, add the soap solution slowly (about
5 drops at a time) from the burette that has been previously
filled to the zero mark. Shake the bottle thoroughly after each
addition of the soap solution.
Continue to add the soap solution until enough has been added to
produce a permanent lather that will last for five minutes when the
bottle has been placed in a horizontal position. About 0.5 c.c. is re-
quired in most cases, to make distilled water form a permanent lather.
This is termed the lather factor. The lather factor should be deter-
mined on each bottle of soap solution.
Testing and Conditioning the Boiler Water
Securing time sample of boiler water
The sample of water to be tested should be taken from the
most circulated part of the boiler. In water tube boilers, the
sample is taken from the water gauge column on the steam
drum. Due to the poor circulation in the mud drum, sample
taken from this point will not be representative. In Scotch
boilers, the sample is taken from the salinometer cock. In
either case, the pipe connections should be blown thoroughly.
The sample should be allowed to cool to room temperature
(about 90° F.).
Measure out a full sample (58.3 c.c.) of boiler water. Place
same in shaker bottle, add the soap solution (about 5 drops at
a time) until a permanent lather has been formed that will
last, or stay unbroken, for five minutes when the bottle is laid
in a horizontal position.
If when 0.5 c.c. of soap has been added and no lather has
been formed, then add 0.5 c.c. of soap, each time. After enough
soap solution has been added to form the permanent lather,
read burette direct in grains per gallon of hardness.
Feed Water Treatment
473
Equipment for Making Hardness Test

ML
20°C
58,3
50
29,15
#4,575-
Graduated Cylinder
1. Measure out a 58.3 c. c.
sample after cooling.
2. Place the measured sample
into the shaker bottle.
(Shaker Bottle)
3. Add soap and shake vigorously, until-
lather lasts, at least, for five minutes.
• Stathis ſem price hanefim Janžeri Bozijnen ja ma para justazijom i send mitļimejima þeiĎ
Lather Factor.
0.5 c. c.
N/50
SUTOMAINS
UNTU
SCARBORN CHEMICAL CO
JEAN ÇMIŞAN PU!
CHICAGO
Standard Soap
Solution Burette
The amount of standard soap solution required from the burette (less 0.5 c. c.
for lather factor) to produce a permanent lather, is the hardness of the water
in grains per gallon.
A
Figs. 2 to 4.-Hardness test. Equipment and method of testing. In testing, the
amount of standard soap solution required from the burette (less 0.5 c.c. for
lather factor) to produce a permanent lather, is the hardness of the water in
grains per gallon.
474
Feed Water Treatment
The boiler water must be maintained at zero hardness. The hardness
of the boiler water can be reduced to this point by the addition of
Formula 77, provided the water be in an alkaline condition.
By adding a few drops of phenolphthalein indicator to a small portion
of the water, this can be determined.
If the phenolphthalein indicator turn the water red, the sample is
alkaline.
If the indicator do not turn the sample red, Formula 88 must be added
to make the water alkaline. The hardness of the boiler water cannot be
reduced to zero unless the water be alkaline to phenolphthalein.
In the determination of the hardness of any water, 0.5 c.c. must be
subtracted from the burette reading.
Alkalinity Tests
Correction of the alkalinity of boiler waters
Measure out 58.3 c.c. of the sample (free from suspended
matter). Place the measured sample in a glass flask, add two
drops of phenolphthalein indicator which will produce a red
color. Add enough sulphuric acid solution from the burette to
turn the sample colorless. Mix well. The amount of acid used
for this test is read on the burette and is recorded as grains
per gallon phenolphthalein alkalinity, or the P reading.
This test should be maintained in the boiler water between six and
ten grains per gallon. This has a direct bearing on the quality of steam
produced.
The P reading can be increased by the application of Formula 88
to the boiler water.
The addition of the hardness reducing chemical, Formula 77, alone,.
in many cases, will reduce the alkalinity.
In a very few cases, the alkalinity or the P reading will increase by
using the hardness reducing chemical Formula 77, by itself. Should
this occur, the alkalinity can be reduced by the addition of Formula 55
(alkalinity reducing chemical). This chemical will also reduce the
hardness.
Feed Water Treatment
475
đaj mini e con una guinea pig na
ML
20°C
583-
29.15
"iso
50
14575.
21-1
Equipment for Making Alkalinity Tests

1. Measure out 58.3 c. c. sample
of boiler water after cooling.


RED
4. Fill sulphuric acid
burette and add to
sample until the
red color changes
to colorless. Read
burette.
2. Place sample in 250
c. c. Pyrex flask.
COLORLESS
6. Do not fill burette
and add more acid
until the straw color
changes to pink.
Read burette.
3. Add two drops of
phenolphthalein
PINK
indicator. Water
will turn red.
Sulphuric Acid
Burette.
Figs. 5 to 12.-Alkalinity tests. Equipment and method of testing.
STRAW
5. Add two drops of
methyl orange in-
dicator and sample
will turn to a straw
color.
T7
Phenolphthalein
Indicator


Methyl Orange
Indicator
476
· Feed Water Treatment
Methyl Orange Alkalinity (M)
Total Alkalinity
I WANT
Use the sample of water from the P. test
After the P test has been made, add two drops of methyl
orange indicator. The sample should turn straw color. Without
refilling burette, add the sulphuric acid solution until the color
changes to a light pink or orange shade. The total acid used is
the total alkalinity in grains per gallon.
NOTE.—If it be desired to economize on solutions, one fourth of a full sample
can be used, or 14.6 c.c. For the alkalinity test, multiply the burette reading by
four, provided 14.6 c.c. sample be used. This test is the neutralization of an alkali
with an acid.
The indicators are used to indicate when enough acid has
been added to affect the change.
Chloride Test (CI)
(Salt)
Use the same sample of water used for the alkalinity test
Add five drops of chromate indicator to the sample from the
alkalinity test and a yellow color will be produced. Add, from
the burette, silver nitrate solution, until the color changes from
yellow to a permanent light brick color, after mixing thoroughly.
The reading of burette represents grains per gallon of sodium
chloride (Salt). If 14.6 c.c. sample be used, multiply burette
reading by four.
No general recommendation can be made as to how much salt con-
centration can be carried in a boiler, since this is governed by various
factors, such as operating rating, etc.
A low salt content, on the other hand, is advisable, especially from
the standpoint of clean steam production.
Feed Water Treatment
477
Equipment for Making Chloride Tests
(SALT)


YELLOW
..
##
##
LIGHT BRICK
1. Add to the sample from the
alkalinity test five drops of
chromate indicator and the
water will turn yellow.
1
2. Fill silver nitrate burette and
add slowly to the sample
until a color change is noted.
Mix thoroughly and when the
sample turns a light brick
color the test is finished. Read
burette.
Chromate
Indicator


Janina sarjan vijana na majan ja kada vɛno
DARA
Viso
11/10
Silver Nitrate
Burette
Figs. 13 to 16.—Chloride tests (Salt). Equipment and method of testing.
478
Feed Water Treatment
Correct Method of Testing for Leaking Condensers
Shut off extra feed and five minutes later secure a sample
from condenser or air pump. Measure out a full sample of pure
distilled water (58.3 c.c.). Place in a glass flask that has been
rinsed three times with same distilled water, add five drops of
chromate indicator. The sample will turn yellow. Add silver
nitrate solution, drop by drop, until the color changes from
yellow to light brick red. Note the number of drops of silver
nitrate required to make the color change in the distilled
water sample.
Measure out 58.3 c.c. of the condensate sample. Place in
flask, add five drops of chromate indicator. Add silver nitrate
solution until the color changes from yellow to light brick red.
If the condensate require more silver nitrate solution for the color
change than the pure distilled water, this indicates a condenser leak,
provided the steam has been tested and shows no trace of salt. If this
same test show more salt in the condensate than the steam test, it is
then definite that the condensers are leaking.
Feed Water Regulators
479
CHAPTER 28
Feed Water Regulators
What is a feed water regulator?
Ans. An automatic device for controlling the flow of feed
water into a boiler.
What is the ideal condition in the production of steam?
Ans. A constant feed of feed water in quantity corresponding
to the amount of steam being produced.
Does a feed water regulator meet this requirement?
Ans. No, only approximately.
How is the output of a boiler affected?
Ans. Inversely by the rate at which the feed water is supplied.
What happens when the feed is intermittent?
Ans. The generation of steam decreases when the feed valve
is open and increases when the valve is closed.
Name a familiar example where intermittent feed is used
to advantage.
Ans. Boiler feed for locomotives.
480
Feed Water Regulators
Explain.
Ans. When going down grade where the power is shut off, the
feed is turned on which prevents the safety valve blowing and
fills the boiler to high level so that on up grade where maximum
power is required, the feed may be shut off, while the excess
water is being evaporated.
Name the various types of feed water regulator.
Ans. They may be classified as:
BUOYANCY FLOAT
THIN
LIGHT
LOW PRESSURE STEAM
1. Displacement.
OUTLET
a. Buoyancy body or float.
b. Specific gravity body.
2. Evaporation.
3. Expansion.
SPECIFIC GRAVITY BODY


THICK
HEAVY
HIGH PRESSURE STEAM
I
Figs. 1 and 2.-Elementary diagrams showing difference between a buoyancy
float and a specific gravity body, and conditions for which they are suit-
able.
276444414)
COUNTER WEIGHT
Describe a displacement regulator.
Ans. The simplest form consists of a hollow metal buoyancy
float placed in the water column which moves up and down
Feed Water Regulators
481
with changes in the water level and operates the feed supply
valve.
By what two methods is this motion transmitted to the
feed supply valve?
Ans. By 1, direct lever connection, or 2, through auxiliary
valve and diaphragm.
What is a specific gravity body as applied to a regulator?
Ans. The term specific gravity body means a hollow cylin-
drical body of such substantial construction that it is too heavy
to float, but of course, weighs less when submerged in water
than when in the steam space.
This is a nice hydraulic fact.
What is used to offset the excess weight of the specific
body and why?
Ans. A counter weight is used so that the combination of the
two is equivalent to a light or buoyancy float.
What is the reason for such construction?
Ans. To prevent the possibility of collapse under steam
pressure.
This is good construction, as the author's own experience with a
buoyancy float which failed to act. When he examined the float he
found that it had actually collapsed. Such construction will not be
efficient unless made very light, that is, with a small factor of safety
against collapse.
What is the real effect of the counter weight on a specific
gravity body?
482
Feed Water Regulators

INLET
STEAM CONNECTION
CONTROLLING VALVE
HAVING VALVE
IN BYPASS
STRAINER
UNION
TO BOILER
EXHAUST
KERNEL
TO WATER COLUMN
bb
GOOD
Fig. 3.-Specific gravity body feed water regulator. In operation, when the
water level in the column is below the opening of the special nipple, steam will
enter the chamber of regulator, and the water in it will be displaced, falling
through the pipe at its bottom to the level of the water in the water column. The
weight or displacement body in the chamber will then fall by gravity to the
bottom of the chamber, the counter-weight and lever will rise, holding the ac-
tuating valve against its top seat, and the exhaust valve will be open to the
air. There will then be no pressure on the piston of controlling valve, and the
latter will be wide open and the boiler taking water. When the boiler fills up to
the opening of the special nipple the same will be sealed by the rising water,
and steam will be cut off from entering the chamber, and that which was in it
will be condensed, slightly reducing the pressure therein, so that the water from
the boiler will fill it to the top. The inside weight or displacement body now
weighs less than it did when the chamber contained steam only, by the weight
of water which it displaces. The counter-weight or outside weight is now heavy
TO DRIP ANGLE VALVE
Feed Water Regulators
483

·····
CHINI
BOILER DRUM
WATER
LEVEL
| | | | | | | | | | | | |
DIAPHRAGM
STEAM TUBE'
GENERATOR
PIPE TO DIAPHRAGM
DIAPHRAGM VALVE
EVAPORATION
Fig. 4. Evaporation type regulator. In operation, when the water drops in the
boiler it will drop a corresponding distance in the steam tube thereby heating
the water in the generator and creating a pressure which forces a proportionate
amount of water down the pipe to diaphragm valve a sufficient distance to
allow enough water to flow through into the boiler to take care of the amount
evaporated. If the load and fire conditions remain constant at this time, the
valve will remain stationary. In actual operation the load changes more or
less making a larger or smaller demand for water and the diaphragm valve
will move proportionately to accommodate the local changes.
Fig. 3.-Text continued.
enough to over balance the inside weight and goes down, while the inside
weight goes up. As the outside lever goes down the actuating valves goes down,
opening the steam connection and shutting the exhaust. This admits the steam
pressure to the piston chamber of controlling valve and forces the piston and
valve down, and shuts off the feed water at once. No more water can enter the
boiler until the water level falls to the opening of the special nipple, when steam
is admitted to the top of the chamber, the water in it falls to the old level, all
the operations are reversed and the controlling valve opens again. These oper-
ations are repeated as the water gets above or below the desired point and the
variation does not exceed one-half inch. When the counter-weight is up this
indicates the boiler is feeding, and when down, that it is not.
484
Feed Water Regulators
Ans. It gets rid of the extra weight which prevents collapse
and virtually transforms a specific gravity body into a float.
What is an evaporation regulator?
Ans. A type of regulator whose operation depends upon the
evaporative effect of a metal tube containing water and steam,
BELL CRANK

STEAM
WATER
RIGID ROD
ANCHOR
WATER LEVEL
EXPANSION TUBE
BOILER
DRUM
CONTROL VALVI
Fig. 5.-Expansion tube type regulator. The expansion tube and rod are fixed
(anchored) at one end and the tube is free to move due to expansion or con-
traction with temperature changes. In operation, the expansion tube is par-
tially filled with water, depending upon the water level in the boiler, and the
load. Now the part of the expansion tube filled with steam is maintained at the
temperature of the steam, since as fast as it radiates heat, it causes condensa-
tion and the liberation of the latent heat at steam temperature. On the other
hand, the lower part of the thermostat is at a temperature considerably below
steam temperature, since the radiation of heat for this part of the tube can take
place only at the expense of the sensible heat of the water. When the water is
at its minimum level and the expansion tube is filled with steam, expansion is
maximum, also when filled with water the contraction is maximum, the length
and feed valve opening operated thereby runs with the height of the water in
the expansion tube.
when enclosed by a vessel containing water, the enclosing vessel
having an outlet which communicates with the diaphragm
chamber of the feed valve.
What is its basic principle?
Ans. The amount of evaporation of the water in the enclos-
ing vessel will depend upon the proportion of the inner tube
Feed Water Regulators
485
filled with steam, which in turn depends upon the water level
in the boiler.
Describe its operation.
Ans. Steam in the inner tube evaporates more or less of the
water in the enclosing vessel, which brings pressure on the feed
diaphragm, opening the valve, to some point corresponding to
the amount of water evaporated.
What is an expansion regulator?
Ans. The basic principle of this regulator is the expansion
and contraction of a metal tube subjected to variable temperature.
How about the movement thus produced?
Ans. It is multiplied by a system of levers which operate the
feed control valve, being so arranged that the expansion of the
tube opens the valve and contraction closes it.
What is essential for proper operation?
Ans. The feed pump must be provided with a governor giving
such control as to maintain an excess pressure in the feed line
so as to meet any demand of the feed water regulator control
valve.
NOTE. When feed water pressure is provided by reciprocating steam driven
feed pumps, it is necessary to regulate the speed of these pumps rather than to
throttle feed water flow with a differential pressure valve. For this service, pump
governor should be installed in the steam line to the feed water pump. In this
position, it maintains a constant excess feed water pressure by regulating pump
speed.
NOTE. Slow and uniform feeding of boilers by regulators causes a saving of
fuel in the feed water heater or ecoromizer, because the regular speed of the water
through the latter allows the feed water to be always heated to a higher degree than
is possible when the flow varies, as is always the case with hand feeding.
NOTE.-Dry steam. A properly designed boiler will not prime or permit its
water to be carried over into the steam pipes if the water level be kept at the middle
gauge. Most cases of boiler priming and water in the engine cylinders are due to
the carelessness of the attendant in al'owing too much water to the boiler. Other
cases of priming is due to bad water or undue forcing. Keep the water to the middle
gauge rather than to the top gauge.
486
Feed Water Regulators

AIR
SUPPLY
Th
AIR
SUPPLY
CONTROLLER PILOTS
STEAM FLOW
RECORDER
WATER LEVEL
RECORDER
BOILER DRUM
AVERAGING
RELAY
FEED
LINE
ORIFICE
HAND-AUTOMATIC SELECTOR
VALVE & POSITION INDICATOR
A
AIR
SUPPLY:
FEED WATER
Ca
KATARAK a
O
Com
STEAM
VALVE
POSITIONER
HANDWHEEL JA
JACK
-FEED WATER
REGULATING VALVE
K
DIFFERENTIAL PRESSURE
VALVE
Fig. 6.-Hook up and elements of a two element air operated feed water control.

Feed Water Regulators
487
NORMAL
WATER LEVEL
GENERATOR
COPPER TUBING
4 PLY METAL BELLOWS-
T
FEED WATER
REGULATOR VALVE
LEGEND
STEAM AT BOLLA PRESSURE
WATER AT BOILER PRESSURE
STEAM IN CLOSED SYSTEST
WATER IN CLOSED SYSTEM
WATER AT EXCESS PRESSURE
B
BLOIY DOWN
THET
Fig. 7.-Evaporation type feed water regulator assembly for 250 and 400 lb.
standards. This type is also called thermo hydraulic control.
Fig. 8.-Diaphragm valve of evaporation type regulator. In operation, force
exerted by hydraulic pressure in the bellows is opposed by a powerful spring
which tends to close the valve at all times. This spring provides a force of at
least 600 lbs. for closing the valve when water level rises in the boiler. The
exact force exerted by this spring may be adjusted by moving the lower spring
plate nearer to or farther away from the upper spring plate, by means of adjust-
ing nuts directly under the lower plate. This adjustment compensates for various
types of boiler operating characteristics or for small changes in the desired
average boiler water level.
488
Feed Water Regulators

This 1/4" cross connection prevents water going over
to thermostat thru steam connection
Henszey monel
boller nipple
44" Gate
valves
#
Make this 3/4 steam connection as short as possible. Bend pipe, do not
use elbows. Slope pipe at least 2 per foot toward boiler so condensation
will drain to boiler. Trapped water will interfere with operation
of regulator Cover with lagging. -
0
CI
Flanges
Connect regulator to same drum as
water column,but not to water column.
Normal water-level-
HEINSZ
Sel center of expansion tube on
normal water level. Do not paint tube:
F
Make this 44"water connection at least 8 long. Must all be below
lowest water level in boiler. Do not cover or paint.
Nuts for adjusting.
valve opening、
Support must be vertical
Tension
relief
Weight must
open valve
Blow-off-
Fig. 9.-Thermostatic expansion tube feed water regulator. It consists of: thermostat, lever and a feed water
valve. The thermostatic tube lies at an angle, and is connected at its two ends by equalizing pipes to the
steam space and water space of the boiler so that the boiler water level lies at about the middle of the
length of the tube. The thermostat and the lever are connected by the hinge pin which goes through the
multiple jaws in the lever, and in the thermostat, and in the frame. In operation, the operating power and
movement originates in the thermostat. The steam in the high end of the thermostat tube is at boiler tempera-
ture. The water in the lower end is cooled by the radiating fins, and approaches room remperature. When
the boiler water level goes down, the water level in the thermostat goes down, and more of the tube becomes
exposed to hot steam. This causes it to expand and the lengthening tube allows the lever to fall and open
the valve which passes more water to the boiler. A rising water level causes a reverse action and reduces
the valve opening so that less water is fed to the boiler. The position of the lever depends upon the tempera-
ture of the thermostat, but it can be adjusted to maintain a higher or lower boiler water level by adjusting
the nut on the lower end of the thermostat. Each 8th turn moves the lever about 38 in.
Injectors
489
P
CHAPTER 29
Injectors
What is an injector?
Ans. A device for forcing water into a boiler against the
boiler pressure by means of a steam jet.
What is the principle upon which an injector works?
Ans. An injector forces water into a boiler because the kinetic
energy of a jet of steam is much greater than that of a jet of water
escaping from the boiler under the same conditions.
What is kinetic energy?
Ans. The energy or stored capacity for performing work
possessed by a moving body, by virtue of its momentum.
What is momentum?
Ans. The power of overcoming resistance possessed by a body
by virtue of its motion and weight. It is that which makes a
moving body hard to stop.
What are the essential parts of an injector?
Ans. The simplest form consists of: 1, a steam nozzle; 2, com-
bining tube; 3, delivery nozzle with check valve; 4, inlet for
water; and 5, overflow.
•
490
Injectors
STEAM ADMITTED
OVERFLOW
STEAM
VACUUM
VALVE OPEN
PRESSURE
WATER.
PRESSURE
BEGINNING TO CLOSE
Mill,
WATER CHAMBER
CLOSED
CONDENSATION
TAKING PLACE
WATER
PRESSURE
OPEN-
VACUUM
CLOSED BY VACUUM
PREVENTS AIR
ENTERING
BOILER
JET VELOCITY
INCREASING
CLOSED
PRESSURE
INCREASING
KINETIC ENERGY OF
JET GREATER THAN
POTENTIAL ENERGY
OF BOILER
OVERFLOW
CHAMBER
OPEN
EXCESS PRESSURE.
WATER FEEDING TO BOILER
Figs. 1 to 4.—Starting cycle of the injector. Fig. 1, steam admitted; flows through the overflow check
valve and passes out through overflow outlet; the action of the steam jet creates a vacuum in the water
chamber; fig. 2, vacuum created in water chamber draws in the water, which meeting the steam in
combining tube, condenses and the jet of steam issuing from overflow (fig. 1) becomes a jet of water rapidly
increasing in velocity, which builds up pressure against the boiler check; fig. 3, the continued increase
in velocity of jet causes pressure against boiler check to exceed boiler pressure and the latter begins to



Injectors
491
Figs. 1 to 4.-Text continued.
open, part of the jet water entering boiler and part flowing out through overflow; fig. 5, velocity of jet
has become so great that all resistance is overcome, the check valve being forced wide open, all the
water entering the boiler. The action of the jet now creates a vacuum in the overflow chamber, which causes
overflow valve to close, thus shutting out the air which would otherwise be forced into the boiler.
WATER
INLET
OVERFLOW
CHAMBER
DVERFLOW
OVERFLOW
CHECK
VALVE
'FIXED
STEAM
NOZZLE
COMBINING
TUBE
DELIVERY
TUBE.
MAIN
CHECK
VALVE
How does an injector work?
Ans. In operation, steam from the boiler, en-
tering the steam nozzle, passes through it, through
the space between the steam nozzle and combin-
ing tube, and thence out through the overflow.
This produces a vacuum which draws in the water
through the water inlet. The incoming cold water
condenses the steam in traversing the combining
tube, and the water jet thus formed is driven at
first out through the overflow, but as the velocity
of the water jet increases, sufficient momentum
is obtained to overcome the boiler pressure, with
Fig. 5.-Rudimentary fixed nozzle, single tube, injector. The assembly of a
steam nozzle, combining and delivery tubes is called a single tube injector,
as distinguished from a double injector which has two sets of nozzles and
tubes, one for lifting, and one for forcing.

492
Injectors
the result that the water enters the delivery tube and passes
the main check valve into the boiler.
The starting cycle of an injector is shown in figs. I to 4.
How are the different types of injectors classed?
Ans. 1, Non-lifting; 2, lifting; 3, positive; 4, automatic;
5, adjustable nozzle; 6, exhaust.
What is a double tube injector?
CONVERGING NOZZLE
ICC
PRESSURE GREATER THAN
THAT OF ATMOSPHERE
DIVERGING NOZZLE

PRESSURE LESS THAN
THAT OF ATMOSPHERE
Figs. 6 and 7.-Lifting and non-lifting nozzles. In fig. 6, the pressure of the
steam as it leaves the nozzle, being greater than that of the atmosphere, there
is no tendency to produce a vacuum to lift the water. When expansion of the
steam takes place within the nozzle, as in fig. 7, the pressure is reduced below
that of the atmosphere, thus producing a vacuum and drawing in the water.
It will be noted that in double tube injectors (see fig. 8) the lifting nozzle is
made diverging, and the forcing nozzle converging.
Ans. Virtually two injectors in one, the first acting to lift
the water and the second to force it into the boiler.
What are the two classes of lifting injector?
Ans. 1, Diverging tube; 2, double tube.
What other types are in general use?
Ans. 1, Positive: 2, automatic; 3, adjustable nozzle; 4, exhaust.
Injectors
493
What is the difference in construction between non-
lifting and lifting injectors?
Ans. In order that an injector may be able to lift its water
supply, the pressure at the end of the steam nozzle must be
less than that of the atmosphere. This result is secured by using
a diverging nozzle. Fig. 7.
What should be noted about the non-lifting injector?
Ans. It is almost obsolete.

LIFTING
SIDE
STEAM TUBES
COMBINING
TUBES
DELIVERY
TUBE
FORCING
SIDE
MAIN CHECK
5
COVERFLOW
Fig. 8.-Rudimentary fixed nozzle, double tube injector. In this type the lifting
tube lifts the water to the injector, and the forcing tube forces the water into
the boiler. This type is adapted to high lifts.
What other method is used to lift the water supply and
adapt the injector to high lifts?
Ans. By providing two sets of nozzles and tubes as in the so
called double tube type.
What is a positive injector?
494
Injectors
Ans. One with a hand operated overflow valve.
What is the object of the hand operated overflow valve?
Ans. This permits operation at high pressure by stopping
the drizzle from the overflow.
What is an automatic injector?
FULCRUM
STEAM VALVE
OPEN
ADJUSTABLE
DOUBLE CONTROL LEVER
FULCRUM


STEAM NOZZLE
OVERFLOW
VALVE
SHUT
Fig. 9.-Rudimentary adjustable nozzle single tube injector. A type suitable
for a wide range of steam pressures.
Fig. 10.—Rudimentary positive fixed nozzle single tube injector. As shown,
one lever operates both the steam valve and overflow valve, opening the steam
valve and closing the overflow valve in unison. This device enables the injector
to operate at high pressures. An ordinary injector can be made positive by
placing a stop cock in a short piece of pipe screwing into the overflow, and
closing the cock after injector is started. It should be noted that such stop cock
arrangement renders injector non-automatic while the stop cock is closed.
Injectors
495
Ans. One that is self-starting after its operation has been
stopped by the interruption of its water supply.
What is the automatic feature and how does it work?
Ans. It comprises two check valves, which when seated,
closes progressively the combining and the overflow chambers
to the atmosphere.
Describe its re-starting action.
Ans. In re-starting, steam blowing through combining tube
ejects the air causing combining chamber check to close and
establishes a vacuum which draws up the water. The jet of
water escapes through overflow until sufficient pressure is ob-
tained to lift boiler check. At this instant the vacuum created
in overflow chamber causes overflow check to close thus pre-
venting air being carried by the jet into the boiler.
What is the advantage of a double tube injector?
Ans. It is desirable for installations where the injector must
lift the water a considerable distance.
How should an injector be constructed to adapt it to
work satisfactory with a wide range of steam pressures?
Ans. It should be provided with an adjustable nozzle so that
the water passage between the steam nozzle and the combining
tube can be varied in size automatically, or by hand.
Selection of Injector
In considering the selection of the type or model required, it
is best to select a machine which will surely take care of any

496
Injectors
X-
WATER
SUPPLY
TO
BOILER
T
STEAM
N
OVER FLOW
Y
O
P
X
O
R
S
Y
V
N
g
N
Figs. 11 to 20.-Single tube fixed nozzle lifting automatic injector. The parts
are: R, steam jet; S, inlet jet; T, ring valve; Y, delivery jet; O, plug; V, tail
pipe; X, coupling nut; N, overflow hinges; P, overflow valve; Z, overflow cap.
In operation, momentary period elapses between the opening of injector
steam valve and the establishment of the jet of water to boiler. During this
interval the steam and water must not be allowed to back up in inlet line,
hence a series of exhaust openings are provided at intervals along the jet
passages. At first the steam and water exhaust from all these openings or
"spills," then the establishment of the jet of water begins at the top and
proceeds downward. It is therefore possible for the exhaust from lower spills
to be drawn in again into the upper spills. Under such conditions the upper
zone of injector may be established and have ceased to "spill." thus inducing
an inward draught at upper spills. Now this upper zone has established be-
cause the steam and water quantities were rightly proportioned for that instant
and that zone. However, if the lower zone (which is not yet established) be
allowed to throw its surplus back up and into the upper zone, the upper zone
will again be disturbed and unbalanced. Therefore, the ring valve is used to
prevent such an occurrence. Just as soon as a vacuum draught is developed at
upper spills, the ring T, is drawn upward to its seat on jet S, forming an auxiliary
chamber around upper zone for its protection. This ring valve T, is to the upper
Injectors
497
condition ever met in service. If a machine be required to work
at its limit of capacity, steam pressure, lift or temperature of
feed water, it will usually give trouble after any appreciable
wear occurs.
Note the following points on selection:
1. Determine the lowest and highest steam pressure which will be
carried at any time.
2. If water is to be lifted, determine vertical distance of lift.
3. If water be not lifted, but is from an overhead tank or from city
water main, the inlet should be throttled to reduce the pressure low
enough for the machine to handle.
4. Determine the temperature of the water supply.
By referring to the working ranges shown in manufacturer's
tables for each type or model, the correct type can be selected.
In many instances, it will be found that more than one type or
model will meet the requirements. The choice of type or model then,
is usually based upon individual preference for one particular type
over another.
How do you select the proper size when full information
is not known?
Ans. A fire tube boiler will evaporate 30 lbs. of water per
hour, per horse power at 100 per cent rating. To find maximum
capacity of the boiler multiply 30 lbs. by number of horse power.
If the boiler is to be operated at other than 100 per cent rating,
multiply capacity at 100 per cent rating by operating rating.
Figs. 11 to 20.-Text continued.
zone just what the outer overflow valve P, is to the injector as a whole. Without
the ring T, the injector could not be operated on the lower steam pressures.
When water is taken from pressure source a special large steam jet is employed.
Hot water is not favorable for low starting. Standard temperature for local
tests is 74° Fahr.
498
Injectors
To allow for unfavorable or emergency operating conditions
add ten per cent to maximum capacity.
For a water tube boiler, the exact same procedure is followed.
The maximum capacity will now be obtained in pounds of water
per hour. Convert this to gallons by dividing by 8.3 pounds per gallon.
After maximum capacity is determined, the proper machine can be
found in the manufacturers capacity tables. The selection will be
governed by operating steam pressure and individual preference as to
type.
Example. What size and type injector would be used to feed a
75 h.p. fire tube boiler at 125 per cent rating, operating at 135 lbs.?
75..
X30..
2250.
X1.25
11250
4500
2250
2812.50..
281.25..
3093.75..
.lbs. of water required maximum capacity
Changing pounds to gallons:
3093.75..
÷8.3=373 gal. per hour
373 gallons per hour will be required.
Refer to manufacturer's tables and select size corresponding.
400..
X30...
H. P.
lbs. per hour at 100 per cent rating
.lbs. of water at 100 per cent rating
Example.
What size and type injector would be used on a 400 h.p.
water tube boiler, operating at 250 lbs. at 200 per cent rating?
12000..
X2
24000...
2400.
lbs. of water at 125 per cent rating
+10 per cent safety factor to allow for emergency
26400
..h.p.
..lbs. per hour
.lbs. per hour at 100 per cent rating
...lbs. per hour at 200 per cent rating
+10 per cent safety factor for emergency
.lbs. per hour maximum capacity required.
Changing pounds to gallons:
26400..
÷8.3=3180 gal. per hour
3180 gallons per hour will be required.
Injectors
499
Refer to tables for size corresponding.
To Start and Stop a Typical Automatic Injector.
1. To start.-Open full the globe valve H, fig. 21, in water
supply first, and then globe valve D, in steam pipe wide open.
If water issue from overflow, throttle the valve H, until discharge
stops, not by steam valve. When water supply is above the injector in
starting, open valve H, only a half turn and then open steam valve D,

M
G
WATER
SUPPLY
K
Joh
DELIVERY
TO BOILER
B-
@
STEAM
PENBERTHE
OVER-FLOW
Fig. 21.-Single tube fixed nozzle lifting automatic injector with connections.
B, injector; D, globe valve in steam pipe; F, check valve in delivery pipe,
G, globe valve in delivery pipe; H, globe valve in inlet pipe; J, water supply
taken from below injector; K, water supply taken from overhead tank; L,
waste pipe from overflow; M, second globe valve in water supply pipe where
an overhead tank is used or supply is taken from water works pressure.
500
Injectors
full. Where two valves H and M, are used, valve M, should be opened
only about one-half turn or a little more, this valve being designed to
reduce the water pressure valve H, always being used to regulate the
supply to injector. Steam valve must be opened full. One half of the
trouble comes from opening only half way.
2. Pet cock.—A pet cock or tee with globe valve placed
anywhere between the check valve F, and the injector will
help very materially in starting on low pressure; leave open
until injector is started, then close.
This is also convenient for draining discharge pipe in winter.
3. To stop.-Close the steam valve.
The water valve H, need not be closed unless the injector be used
as a non-lifter, or lift is considerable.
4. To test for leaks.-Plug up end of water supply pipe, if
possible, then fit a piece of wood into overflow cap Z, fig. 11,
so that when screwed down it will hold the valve P, in place,
then turn on steam and it will locate leak. Do not fail to do this
in case of any trouble.
5. Jet Liming.-Soak in one part muriatic acid and seven
parts water as long and as often as necessary to keep parts
free from lime.
6. Re-grinding Overflow Valve. Should valve become
coated with lime or become rough, take off cap Z, fig. 11, and
with a screw driver turn valve P, back and forth, which will
grind it to a seat. A little emery flour on the under side of
valve will be of great advantage.
7. To Clean.-To clean injector, unscrew bottom plug O,
and the removable jet Y (which rests in it) will follow the
plug out.
Injectors
501
Turn on steam (not less than 40 lbs.) and all dirt will be blown out.
Examine all passages and dull holes and see that no dirt or scale has
lodged in them.
Replace jet by setting it in plug (which acts as a guide) and screw
into place tightly. Be careful not to bruise any jets, and use no
wrenches on body of injector.
8. Repairs. Send to your dealer or manufacturer stating
number on the injector, also letter, ordering according to names
given for corresponding parts.
You can put in new parts yourself as all jets except inlet come out
without a tool and this jet can be removed with a piece of gas pipe
slotted at one end.
What should be done before connecting an injector and
why?
Ans. Blow out steam pipe thoroughly so as to remove any
dirt, rust or scale that may have accumulated in pipes, other-
wise the injector will become stopped up by this dirt when
starting and will refuse to work. This is important!
Points on Connecting
(Refer to Fig. 21)
1. Tail Pipes or Nipples.-Don't use a "Stillson" to screw
these into pipes. There is an iron lug in box that fits into
square hole in the end of tail pipe on which to use a wrench.
2. Steam.—Take steam from highest point of boiler possible
and never connect with any steam used for other purposes.
If steam pipe happen to be a size smaller than injector connections,
it will work O.K. if not too long.
502
Injectors
3. Repack Stem on Water Valve H (Nine out of each ten
leak). Every valve as shown must be used. Valve H, put
near injector. Use globe valves for H and D, not straightways.
Place valve H, so that it shuts against the supply, that is, so
the water comes up under the seat.
Many people put these on just the reverse.
If water supply come from water pressure of over 25 lbs. use a size
smaller valve H, and water supply pipe than injector couplings, that is,
for a 1 inch injector, use ¾ in. valve and water supply pipe. If not
convenient to do this, use two valves H and M, in water supply pipe.
Never use a pipe smaller than injector connections when water supply
is taken from a lift.
If more than ten feet of water supply pipe be used on a lift, such
pipe and the valve in this pipe should be a size larger than the injector
fittings. If there be a very long pull in addition to a very long lift, a
pipe two sizes larger is preferable. This pipe must be tight. When
forcing through a heater, place a check valve between the heater and
injector.
The strainer furnished is a special mesh and must be used, or one
equally as fine. On a lift of over ten feet, a foot valve on the lower end
of the water supply pipe is a great advantage in starting injector, and
a great saving in steam.
4. Discharge.-This pipe should be full size of injector con-
nections and may be larger if desired.
Place check valve F, at least two feet from injector if possible, and
be sure valve lifts freely.
5. Overflow. A short piece of pipe may be screwed into
overflow to carry off waste. A long piece interferes with vacuum
and must not be used on a long lift or draw.
Place a large piece of pipe under overflow, if there be a lift, or a
waste pipe cannot be ari anged, so that discharge end is in sight.
Injectors
503
Possible Causes of Injector Failures
If the injector be new, it is probable that any trouble is due
to faulty installation or conditions. Every injector is tested.
through its entire range under actual working conditions at
the factory.
It is well to check carefully to see that the proper type and
size has been installed.

M
STEAM
SUCTION
S
ec
#E
OVERFLOW
DELIVERY
Fig. 22.-Single tube sliding nozzle lifting automatic injector. The parts are:
S, sliding steam nozzle; V, lifting tube; C and D, combining and delivery
tubes; R, auxiliary check valve; P, overflow valve; O, steam plug, M, steam
valve and stem; N, packing nut; K, steam valve handle; A, coupling nut;
B, tail pipe; X, overflow cap; E, nut for stem M. In construction, a sliding
steam nozzle is provided. In operation, when this nozzle is in the forward
position enough water will flow in to work from 25 to 90 lbs. For pressures
above 90 lbs., turn handle K, until the nozzle is drawn to its extreme backward
position which will admit sufficient water for pressures up to 150 lbs.
Next check installation and operating instructions given in
the catalog.
504
Injectors
If after checking these points, the trouble be not found, the
following suggestions should be checked:
1. If injector fail to lift the water, trouble may be
due to:
Too low steam pressure for the lift.
Water pipe or strainer clogged.
Water supply too hot.
Overflow pipe too small or end restricted. It should be large with
ends open to allow free escape of steam.
10
82-
5 33
8
6 4
27
37
11
12 14
29 28 26
38
13 15
16
37
23-
Wet steam.
Combining tube clogged.
Overflow valve stuck.

22
23A
25
24
18
19
F
3
37
39
-21
39-
Fig. 23. Single tube locomotive pattern injector. To operate pull lever back
only far enough to lift water, and then wide open. Regulate water with water
valve. Overflow valve must not be closed except when injector is to be used
as a heater. The parts are: 1. Body, back part; 2, body, front part; 3, line
check; 4, steam valve hub; 5, steam valve nut; 6, steam valve gland, 7, over-
flow nozzle; 8, lever handle; 8½; screw handle; 9, st. valve crosshead; 10,
crosshead lock nut; 11, st. valve stem; 12, swivel nut; 13, steam valve; 14,
steam valve washer; 15, primer; 16, steam tube; 17, intermediate tube; 18,
condensing tube; 19, delivery tube; 20, line check valve; 21, stop ring; 22,
overflow hub; 23, overflow valve stem; 24, overflow valve; 25, overflow pack,
nut; 26, water valve hub; 27, water valve spindle; 28, water valve pac.
gland; 29, water valve nut; 33, lever links (pair) 37, coupling nut; 38, coupling
(C.P.); 39, coupling (I.P.); 23A, overflow valve handle.
Injectors
505
Loose lining in water hose.
End of water pipe not submerged.
A leak in the water pipe.
Foreign matter, dirt, scale, iron cuttings or red lead drawn in or
blown in through the steam or water pipe clogging tubes and
nozzles and interfering with the proper operation of the valves.
This is a common cause of trouble.
2. If the machine lift the water, but do not force it
into the boiler, trouble may be due to:
A leak in the water pipe,
Węt steam.
Insufficient steam pressure.
Steam taken from pipe which furnishes steam for other purposes.
This should not be done.
Combining tube clogged.
Overflow valve leaking or not seating properly.
Delivery pipe clogged.
Check valve in delivery pipe not lifting sufficiently or not lifting
at all.
An obstruction between injector and check valve, or between the
check valve and boiler. Examine the delivery pipe where it enters
the boiler. In many cases it will be found choked with lime or
sediment which almost closes the opening. Often the coils of the
feed water heater through which the water is being forced are badly
clogged.
3. If steam and hot water come out of the overflow
together, trouble may be due to:
Steam pressure being too high for the lift.
Water supply too hot.
Water pipe clogged.
506
Injectors
4. If the injector start but break, trouble may be due
to:
Water supply not correctly regulated.
Leak in water pipe admitting air to the injector. This is a com-
mon cause of trouble.
Dirt, sediment, lime or some other form of obstruction in the
delivery tube. This is a common cause of trouble. An obstruction
between injector and check valve or between check valve and the
boiler.

jour
STEAM DIRECT FROM BOILER
PAT
UNIVERSAL ELKOR INE'S
L-SCHUTTE & CO. PHILA.
Jo
DISCHARGE TO BOILER
WATER SUPPLY
OVERFLOW TO WASTE
Fig. 24.-Double tube fixed nozzle lifting positive injector and connections.
The lower tube is for lifting the water to the injector, and the upper tube for
forcing the water in the boiler. Injector is shown in closed position of the
operating handle. To start, the left handle is moved slowly; the quantity of
feed is regulated by valve on water supply line. A strainer should always be
attached to the water supply line when water is not clear.

Injectors
507
B
2
STEAM
TO WATER SUPPLY
OR
OVERHEAD TANK
SUCTION
2
OVERFLOW
of
pet
3
TO BOILER
C
L
CONRAND
D
Fig. 25.-Installation of "Inspirator" injector. Directions for operation: To start.-
Open the overflow valves Nos. 1 and 3, close forcer steam valve No. 2, and
open wide the starting valve in the steam pipe. When water appears at the
overflow, close No. 1 valve, open No. 2 valve one quarter turn, and close-
No. 3 valve. The inspirator will then be in operation. To stop: Close starting
valve in the steam pipe. Caution: No. 2 valve should be closed with care to
avoid damaging the valve seat. When inspirator is not in operation, both
overflow valves, Nos. 1 and 3 should be open, to allow the water to drain
from inspirator. If suction pipe be filled with hot water, either cool both it and
the inspirator with cold water, or pump out the hot water by opening and closing
the starting valve suddenly. No adjustment of either steam or water supply is
necessary for varying steam pressures, but both the temperature and quantity
of the delivery water may be varied by increasing or reducing the water
supply. The best results will be obtained from a little experience in regulating
the steam and water supply.

508
Injectors
General Caution.-Bear in mind that for good results, the
steam should be dry; all pipes and valves full size; and the water
pipe absolutely air and water tight.
If the machine be old, trouble is probably due to certain parts being
worn. Repair parts can be bought and inserted by the engineer in
charge, or the injector may be sent to the factory for a general over-
hauling.
Unless you be sure that you have facilities to do your own repair
work-return the injector to the factory.
STEAM
Fig. 26.-Type H.D. ejector.
tiple
bo 9.0
adi to ro
Solo-bid
pinotzo 5
tops H
tod no
hipth of
SUCTION
STEAM
H-D
H-D
Wo
othevo
OP
wloy
ach biovo
olhevo
ofoteni mos
od sa
bap i dtoo loos 1900 tow
Fig. 27.-Type H.D. noiseless water heater. These heaters are designed for all
2 uses where it is desired to heat liquids by direct steam pressure. The steam
issues from an annular steam nozzle, and comes in contact with the water
flowing through and around nozzle. By this arrangement the greatest quantity
prof liquid is heated with practically no noise. By the rapid circulation produced,
a uniform temperature of the liquid is assured,
que solow bro most s
4
DELIVERY
NOISELESS
WATER HEATER
DELIVERY
1.29.01
noaO
Steam Traps
509
CHAPTER 30
Steam Traps
What is a steam trap?
Ans. An automatic valve that will pass condensate but will
not allow steam to escape.
Where are steam traps used and why?
Ans. They are applied to two general classes of equipment:
1, steam mains, headers, separators, purifiers, etc.; 2, steam
heated units such as pipe coils, jacketted kettles, unit heaters,
water heaters, etc.
What is the service performed by traps on class 1 appli-
cations?
Ans. Primarily, discharging condensation carried over from
the boiler, and slugs of water that interfere with proper flow
of steam and which might cause damage in engines, turbines
and steam heated machines.
What must a trap be able to handle besides condensate?
Ans. Air.
On class 1, the quantities of air to be handled are very small except
at the ends of headers and mains.
NOTE. Steam traps are applied to two general classes of equipment. Class
1-Steam mains, headers, separators, purifiers, etc. Class 2-Steam heated units
such as pipe coils, jacketed kettles, unit heaters, water heaters, etc. The service
performed by traps on Class 1 applications is primarily discharging the unavoidable
condensation, carry-over from the boiler, and slugs of water that interfere with
proper flow of steam and might cause damage in engines, turbines, and steam heated
machines. Ability to discharge air is a trap requisite, but the quantities to be han-
dled are small except at ends of headers and mains. The service performed by traps
on Class 2 applications is discharging both air and water so that the space drained
can be kept filled with hot, dry steam. This assures both maximum efficiency and
capacity for the unit drained.
510
Steam Traps
What is the service performed on class 2 applications?
Ans. On class 2, applications, the service performed is dis-
charging both air and water so that the space drained can be
kept filled with hot, dry steam.
How would you classify steam traps in general?
Ans. 1, Non-return; 2, return; 3, intermittent; 4, continuous.


INLET
BUOYANCY FLOAT
OUTLET
OUTLET
BUCKET
EVAPORATION TUBE
INLET
OUTLET
INLET
INLET
COUNTER WEIGHT
SPECIFIC GRAVITY
BODY
NANAM
DIAPHRAGM
OUTLET


EXPANSION TUBE
OUTLET
STUFFING BOX
SPRING


OUTLET
Figs. 1 to 6.—Elementary steam traps. Fig. 1, buoyancy float trap; fig. 2,
counterweighted specific gravity body trap; fig. 3, bucket trap; fig. 4,
differential trap; fig. 5, evaporation trap; fig. 6, expansion trap.
Steam Traps
511
What is the difference between a non-return and a
return trap?
Ans. Traps are said to be non-return when they do not return
the condensate to boiler, or return when they return the con-
densate to the boiler.
To what does the terms intermittent and continuous
relate?
Ans. They relate to the nature of the discharge and are
accordingly self defining.
How do most traps work?
Ans. With intermittent discharge.
How do return traps return condensate to the boiler?
Ans. In return traps is a vessel automatically vented to the
atmosphere and when the vessel fills up sufficiently to sink, the
vent is automatically closed and the boiler pressure is allowed
to enter on surface of condensate, thus equalizing the pressure,
causing the condensate to drop to a lower level which is the
level of the water in the boiler. When the vessel is empty it is
allowed to raise up again and vent itself, allowing more con-
densate to run in.
What operates the return trap?
Ans. The weight of the condensate.
How should such traps be installed?
Ans. They should be about 4 ft. above the boiler water line
to work satisfactorily.
Can returns from common traps be emptied into a non-
return trap?
512
Steam Traps
Ans. Yes, but it would be necessary to have a check valve
on each return from common trap.
What working principle will give approximate continuous
discharge?
Ans. Evaporation.

Fig. 7.-Thermal type liquid expansion trap, especially adapted for out of
doors, or where condensation is discharged directly to atmosphere. This trap
can be adjusted by the user to discharge condensate at low temperatures
never higher than 212° F. when discharging to atmosphere. Sometimes this
matter of adjustment is important especially in cases where it is necessary to
get the most amount of heat from the liquid before discharging it
NOTE. In many cases where it is essential that a trap operate continuously
a test valve is placed in the discharge line near the trap. If there be a possibility
that the opening of the test valve will draw from other traps on the same line a
check valve can be arranged in the line to prevent it. Gravity drainage should
be provided when possible. If this be impossible, it is a good plan to seek expert
advice in laying out the piping system.
NOTE-The principal thing to watch for in the maintenance of steam traps is
the accumulation of dirt which may hinder the operation. Frequent cleaning and
inspection at regular intervals is a necessity. Just what maintenance is needed
and the frequency of inspections will depend upon the service required and the
kind of trap used. Traps having valves will need attention and renewal from time
to time, as will link motions or other moving parts. As a rule a trap will give long
and efficient service, in fact so long that ordinary maintenance is often neglected
until trouble develops-sometimes long after trouble develops.
Where should a steam trap be installed?
Ans. At the lowest point of coil or pipe.
Is there any other way that condensate may be put back
into a boiler except by using a return trap?
Ans. Yes, by using a steam loop.
Steam Traps
513
What good is a water gauge on a trap?
Ans. It indicates whether or not the trap is working.
What is an expansion trap?
Ans. One whose action depends upon expansion and contrac-
tion.

DDDD Hisa
120
** G* 1
Fig. 8.-Free floating valve. The valve mechanism uses no fixed pivots. The
hemispherical ball valve is fastened near one end of the free floating stainless
steel valve lever. This lever is guided by two vertical pins which fit loosely in
ears extending from the sides of the valve lever. In closing, the hemispherical
valve is lifted directly to the orifice by the buoyancy of the inverted bucket.
When the bucket fills with water and sinks, it pulls down on the end of the valve
lever. As the lever moves, the knife-edged fulcrum bears against the face of
the valve seat and through high leverage the valve is pulled directly away
from the orifice.
How does a buoyancy float trap work?
Ans. The buoyancy float at the end of a lever operates a
valve controlling the discharge by the rise and fall of the
condensate,
:

514
Steam Traps
How does a specific gravity body trap work?
Ans. The heavy specific gravity body lightened by a counter-
weight is virtually the same thing as a buoyancy float.
TEST OUTLET
VALVE SEAT
FULCRUM
POINTS
HEMISPHERICAL
VALVE
VARIABLE
WATER LEVEL
INLET
OUTLET
CAP
BUCKET
STRAP
AIR VENT
BUCKET
BUCKET
WEIGHT
BODY
Fig. 9.-Typical inverted bucket trap with free floating valve as shown in fig. 8.

Steam Traps
515
How does an upright bucket
trap work?
Ans. The condensate rises
until it overflows into the
bucket which then sinks and
opens the valve for discharge.
How does a differential trap
work?
AIR
AIR
Ans. A spring acts to hold
the valve open. In operation
the condensate entering an
upper chamber flows down
through a tube and the pres-
sure of water then acting on a
diaphragm overcomes the
spring and closes the valve
holding it shut until the water
in upper chamber overflows
into a pipe connected to top
of diaphragm chamber, bring-
ing water on upper side of the diaphragm equalizing hydraulic
pressures on diaphragm which allows spring to open valve to
discharge condensate.
AIR
lastica us
Fig. 10.-Addition of thermic vent
gives a blast trap. Adopted to
applications where large circuits of
air must be handled quickly when
steam is first turned on.
How does an expansion trap work?
Ans. The actuating element of one type is a curved sealed
tube containing a small quantity of a liquid. In operation when

516
Steam Traps
VALVE OPEN-Main fow through seat
syd e
K
G
quasub woll
D
F
-H
VALVE CLOSED-Main Row shut off
Figs. 11 and 12.-Impulse type trap. It operates on the principle that hot
water under pressure tends to flash into vapor when its pressure is reduced.
This flashing action is utilized to govern movement of valve F, by causing
changes in pressure in control chamber K, above valve control disc L; these
changes of pressure occur with change of temperature of the condensate entering
trap. Valve F, the only moving part in the impulse trap, moves up and down
in control cylinder D, and closes on seat G. Line pressure at trap inlet exerts
upward force on control disc to lift valve; pressure in control chamber exerts
downward force to close valve; pressure in trap outlet is usually atmospheric
pressure or any back pressure up to 25 per cent of inlet pressure. Cor.trol
flow: The flow of condensate is divided as in fig. 11. When valve is open,
main portion of condensate discharges freely through seat; a small portion,
called the control flow, is permitted to by pass continuously through control
chamber into outlet side of trap. Control flow enters chamber through annular
orifice around disc L; it discharges through control orifice in center of valve F.
When system is heating up, condensate is not at high temperature, control
flow through center orifice does not change volume, discharge through this
orifice reduces chamber pressure and valve opens to discharge air and con-
densate. When system comes up to heat, condensate is at near-stream
temperature and control flow entering chamber starts to flash into vapor due
to reduced pressure. Flash vapor increases volume of control flow, discharge
through center orifice is choked, pressure in chamber builds up, closing valve
(see fig. 12) and stopping all discharge of hot condensate except small amount
that flows through center orifice.

Steam Traps
517
16
TYPE
746
18
23
27
25
30
27
31
19
15
26
12
29
10
28
94
20
21
32
35
39
40
190764
47
ATN
49
37
41
48
45
43
2
B
Fig. 13.-Boiler return trap for automatically returning condensate back to high
or low pressure boilers without the use of a boiler feed pump or ejector. In
operation, condensate flows into the trap through inlet A. As the water
level in the trap raises to a high level, the ball weight number 16 over balances
the float, in turn over balancing the ball weight number 29, which operates
the control valve, opening the steam supply from the boiler at port C. A
check valve in the inlet line keeps this steam supply from going into the
returns. Thus, this steam supply makes the pressure in the trap the same as that
in the boiler, and by gravity the condensate goes into the boiler through
discharge B. As the level in the trap drops the action is reversed and the
condensate again flows into the trap. When the trap is not discharging, that is,
when condensate is draining into it, the trap is vented to the atmosphere,
thereby automatically eliminating any air that might have entered into the
returns.
518
Steam Traps
trap chamber is full of condensate no vapor is formed in the tube,
which under this condition holds valve open. When condensate
is discharged the chamber fills with steam, causing evaporation
within the tube which tends to straighten and so closes the valve.

11
Her p p q r r r
Fig. 7.-Thermal type liquid expansion trap. In construction a flexible metal
bellows is partially filled with a volatile liquid and tightly sealed. In
operation, when the trap becomes hot the liquid boils, creating a vapor
pressure, which is always slightly higher than the pressure surrounding the
bellows, and the valve is closed. When condensate gathers around the bellows
and cools slightly, the vapor condenses again and the bellows contract and
open the valve. This cycle is repeated as often as necessary. These traps are
used in heating, drying, baking and evaporating operations.
How does an inverted bucket trap work?
Ans. With bucket down and steam turned on, water fills
body. Excess water escapes through orifice until steam reaches
Steam Traps
519
trap and fills bucket, which floats and closes orifice. When steam
condenses water enters. Bucket loses buoyancy, pulls on lever.
When weight of bucket times leverage equals pressure on valve,
trap opens.
What are the applications of inverted bucket traps?
Ans. They are extensively used for drawing water from com-
pressed air lines, separators, after coolers and receivers.
What should be done before placing an inverted bucket
trap in service?
Ans. Prime the trap.
What is a "blast" trap?
Ans. An inverted bucket trap provided with a thermic vent.
What is its application?
Ans. It is used where large amounts of air must be handled
quickly when steam is first turned on.
Describe the construction.
Ans. The inverted bucket is equipped with an auxiliary air
vent which is controlled by a flat disc mounted at the end of a
strip of rustless thermostatic bi-metal.
<
How does it operate?
Ans. When steam is first turned on, the auxiliary vent in the
top of the bucket is wide open. Air and water blow straight
through until steam comes in and causes the bi-metal strip to
bend upward, closing the auxiliary vent. Thereafter the trap
works the same as an ordinary inverted bucket trap.

520
Steam Traps
39
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Sp9val
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Figs. 15 and 16.-Piston operated compound trap. Fig. 15, closed; fig. 16
Fig 15 close
open. This trap is designed for draining steam purifiers; separators, flash tanks,
continuous blowdown systems, de-super-heaters, hot water heaters, or any
other steam using equipment producting very large volumes of condensate
at low, medium or high pressures. In operation, fig. 15, the pilot trap body is
full of water, in which the inverted bucket floats and holds the pilot valve
closed. Steam and water reach the bucket through the pilot tube that extends
from the top of the receiving chamber down to the pilot trap body and up
under the inverted bucket. When water fills the receiving chamber as illus-
trated in fig. 16, condensate enters the pilot tube. The inverted bucket then
becomes filled with water and sinks, opening the pilot valve. The pilot
valve discharges against the head of the piston which has an area greater
than that of the main valve. This forces the piston up, opening the main dis-
charge valve, and letting water escape from the receiving chamber. As the
main valve opens wide, a relief port is uncovered, reducing the pressure
under the piston and preventing excess piston travel. While the bottom of the
piston is uncovered the pressure relief port, the skirt of the piston begins to
close the main discharge port, which further insures against excessive upward
movement of the piston and main valve. When steam again enters the re-
ceiving chamber and flows down through the pilot tube, the inverted bucket
qefloats, closing the pilot valve before all the water leaves the receiving chamber.
With the pilot valve closed, pressure is relieved under the piston and it drops,
closing the main valve.
Steam Traps
24
Steam Trap Troubles
A steam trap, like any other mechanical device, may cease
to function or fail to give satisfactory service.
The following summary of steam trap troubles will prove
helpful in locating and correcting any difficulty that may occur.
Whenever a trap fails to operate and the reason is not readily
apparent, the discharge from the trap should be observed. If
the trap be installed with a test outlet, this will be a simple
matter, otherwise it will be necessary to break the discharge
connection.
No Flow. If the trap fail to discharge condensate, check
the following:
1. Pressure may be too high.
a. Wrong pressure originally specified.
b. Pressure raised without changing valve orifice.
c. Pressure regulating valve out of order.
d. Pressure gauge on boiler reads too low.
2. No Water Coming to Trap.
a. Trap installed above a leaky by pass valve.
b. Broken or damaged siphon pipe in siphon drained cylinders.
c. Broken valves in line to trap.
d. Pipe line or elbows plugged with dirt.
e. Vacuum in water heater coils may prevent drainage-install
a 14 in. check valve as vacuum breaker between trap and coil.
3. Bucket Vent Plugged.
a. Caused by bad water conditions and usually can be prevented
by installing a strainer ahead of trap.
522
Steam Traps
4. Trap Body Filled with Dirt.
a. Strainer will prevent accumulation of particles too large to be
carried out with condensate.
G
5. Worn or Defective Mechanism.
a. Examination will show which parts are worn or may otherwise
require replacement.
Continuous Flow.-If the trap discharge water continu-
ously check the following:
1. Trap Too Small.
a. Larger traps or additional traps should be installed.
b. High pressure orifice may be used for a low pressure job.
Install right size orifice.
2. Abnormal Water Conditions.
a. Boiler may foam or prime, throwing large quantities of water
into steam lines. A separator should be installed or else the feed
water conditions remedied.
Steam Loss.-If the trap blow live steam, trouble may be
due to any of the following causes:
1. Valve Fails to Seat.
a. Piece of scale or pipe cutting lodged in orifice.
b. Worn seat.
2. Trap May Lose Its Prime.
a. If the trap be blowing live steam, close the inlet valve for a
few minutes. Then gradually open. If the trap catch its prime the
chances are that the trap mechanism is all right.
b. Prime loss is usually due to sudden or frequent drops in steam
pressure. On such jobs the installation of a check valve is called
for and, if possible, locate the trap well below the unit or line
that it drains.
Steam Traps
523

STEAM SUPPLY
BOILER
TRAP

A
B
TRAP
C
TO BOILER
Figs. 17 and 18.-Points on traps. A steam trap will not operate unless the
pressure on the coil drained by the trap is higher than the pressure in the line
leading back to the boiler room. For example, a trap is of no value on the
coil shown in fig. 17. With 10 lbs. steam pressure in the boiler, the pressure
in the coil will be practically 10 lbs. Hence the pressure on the inlet to, and
discharge line from the trap will both be 10 lbs. Under these conditions the
trap will not be able to function properly and the comparatively small orifice
in the trap will interfere with the normal gravity drainage. In a like manner,
it is not practical to put a trap in line A, of the heating coil shown in fig. 18.
Steam blowing through the untrapped lines B and C, will equalize the pressure
between the inlet and discharge sides of the trap so that the trap has no chance
to operate properly. Both of these cases, of course, are elementary and are
perfectly understood by any engineer. Nevertheless cases similar to these
occur almost every day. In large plants with complex piping, it is easy to make
mistakes. For this reason, it is always good practice to check the piping
hook-up carefully every time a trap is put in. Better still, test the supply and
return lines with a pressure gauge and then it will be known whether proper
pressure differential is through the trap.
524
Steam Traps
1914
Mysterious Trouble.-If trap operate satisfactory when
discharging to atmosphere but trouble be encountered when
connected with return line, check the following:
1. Back Pressure May Reduce Capacity of Trap.
a. Return line too small.
b. Other traps may be blowing steam.
c. Vent in return line may be plugged.
d. Obstruction in return line.
2. High Vacuum in Return Line.
a. Increases pressure differential beyond which the trap may
operate. Remedy, install higher pressure trap.
Sluggish Heating. When trap operates satisfactorily but
units fail to heat properly.
1. One or more units may be short circuiting and the proper
remedy is to install a trap on each unit.
2. Trap may have inadequate air handling capacity.
a. A larger trap may be required or else the use of a thermic
unit is advisable.
Imaginary Troubles.-If it appear that steam escapes every
time trap discharges, remember:
Hot condensate forms flash steam when released to lower
pressure.
Flash steam usually condenses quickly in the return line.
Safety Valves
525
CHAPTER 31
Safety Valves
What is the most important fitting on a boiler and why?
Ans. The safety valve because it prevents the steam rising
above the safe working pressure, that is the pressure at which
the safety valve is set.
What is a safety valve?
Ans. A circular valve connecting with the steam space of a
boiler and weighted to such an extent that when the pressure
of steam exceeds a certain point the valve is lifted from its seat
and allows the steam to escape.
How is the valve loaded?
Ans. Either by a weight or by a spring.
What care should a safety valve receive and why?
Ans. It should be kept clean and raised by hand every
morning to insure that it is in proper working condition.
Why should it be raised so often?
Ans. So that it cannot stick in its seat through the accumu-
lation of dirt and scale.
526
Safety Valves
Name the different types of safety valve.
Ans. 1, The dead weight; 2, lever with weight; 3, lever with
spring; 4, spring.
What types are in general use?
Ans. The weighted lever safety valve and the spring safety
valve.


////
C.
DEAD WEIGHT
llläffiti..
50 C
it
COMBINATION
LEVER AND SPRING
LEVER
"100


"MALE
SPRING
Figs. 1 to 4.-Elementary safety valves showing various types. Fig. 1, dead
weight valve; fig. 2, lever valve; fig. 3, combination lever and spring valve;
fig. 4, spring valve.
Safety Valves
527
•
What is the application of the dead weight valve?
Ans. It is sometimes used for very low pressure apparatus
as in steam heating.
Where is the combined lever and spring valve used?
Ans. Principally in England.
Where is the lever valve used?
Ans. The lever valve is used principally in stationary practice
and sometimes on ferry boats, side wheel steamers and other
craft navigating quiet waters and carrying moderate or low
pressure steam.
The lever valve is not now used so extensively as formerly.
What type valve is required in the "Code States"?
Ans. The direct spring loaded valve.
Why do the "Code States" prohibit lever or dead weight
valves?
Ans. Because they are too easily tampered with.
What are the characteristics of a lever valve?
Ans. The lever valve has no definite "pop" point, the valve
lifting slowly in opening and settling gradually in closing.
What is the difference with spring valves?
Ans. They have a positive opening to practically the full
amount.
What are the essential parts of the lever safety valve?
Ans. 1, A valve chamber containing the valve seat, inlet and
528
Safety Valves
outlet opening; 2, a cover containing the upper spindle and
lever guides, also an arm having a pivot hole at its end forming
the fulcrum; 3, a valve and spindle, the latter being attached to
the valve and the projecting part terminating in a knife edge;
4, a lever, pivoted at one end to the projecting arm of fulcrum,
FULCRUM

All
VALVE
CHAMBER
KNIFE EDGE
VALVE
INLET
II
///////
LEVER GUIDE
60
LEVER
UPPER GUIDE
VALVE SEAT
PRESSURE
NOTCHES
OUTLET
VALVE SPINDLE
LOWER GUIDE
STOP
lad
Fig. 5.-Sectional view of a lever safety valve showing essential parts.
BALL
in contact with the knife edge of the spindle at an intermediate
point and weighted at the other end with a ball.
Why is a lever valve objectionable on vessels navigating
rough water?
Safety Valves
529
Ans. The inertia of the weight produces a variable pressure
on the valve tending to close and open the valve respectively
with rise and fall of the boat on the waves. Moreover, when the
boat rocks, the horizontal position of the lever is disturbed and
the blowing pressure of the valve is lowered.

V
L
L
Fig. 6.-Diagram of a lever safety valve showing decrease of the weight's effect,
as the result of incline in a heavy sea. In the diagram, L, is the length of the
lever arm, the full length being effective when horizontal but when inclined
the effective length is reduced.
What precaution should be taken with a lever valve?
Ans. The lever should be raised frequently permitting the
valve to blow to guard against the valve sticking to the seat.
J
530
Safety Valves
CONTACT
SURFACE
POP LIP
SEAT
1
MHIP
GUIDE
SPINDLE
AREA PRESENTED
TO STEAM WHEN
VALVE IS SEATED
C
SPRING
VALVE
BEGINNING
OF POP
POP
CHAMBER
ADJUSTABLE
POP RING
$f
THIETBR
QEII.
EXCESS AREA
PRESENTED TO
STEAM AS SOON
AS VALVE LEAVES SEAT
CENTRIFUGAL FORCE
DUE TO ACTION OF LIP
1
COMPLETION
OF POP
FORCES
CAUSING
THE POPI
DIO
PRESSURE ON
EXCESS AREA
Figs. 7 to 9.—Construction and operation of a pop valve. Fig. 7, shows the essential parts with their names.
In operation, as the valve begins to lift, steam rushes into the pop chamber and being confined (or par-
tially so) therein acts on an excess area as indicated by the shaded ring, fig. 8, causing the valve to suddenly
is to regulate the "blow down
lift or "pop" to its full opening, as in fig. 9, hence the name pop valve. The main object of the pop ring
or closing pressure. To regulate, if valve reduce pressure too much, lower
pop ring, if not enough, raise pop ring.



Safety Valves
531
What is a pop safety valve?
Ans. One so constructed that it opens very suddenly like a
cork popping out of a champagne or sparkling burgandy
bottle and remains open until the pressure is reduced a pre-
determined amount.

ANGRIHERITED
POWELL
1/1
Fig. 10.-Typical steam bronze angle pattern lever safety valve with screwed
ends for working pressures up to 150 lbs. Showing exterior construction.
Describe how the spring resistance acts.
Ans. The force due to the compression of the spring opposes
the steam pressure and keeps the valve on its seat until the pres-
sure of the steam on the valve becomes strong enough to over-
come the resistance of the spring.
532
Safety Valves
How is it constructed?
Ans. The construction is such that as soon as the valve
begins to open, an excess area of the disc is presented to the
escaping steam, hence it suddenly opens wide.
What is the object of a pop safety valve?


HID
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Figs. 11 and 12.-Exterior and sectional views of spring pop safety valve.
A spring of known strength, whose tension is adjustable to desired pressure,
holds the valve upon its seat. By the lever attached to the valve stem, however,
the valve may be raised, allowing the steam to blow off whenever desired.
Ans. To prevent too frequent blowing of the valve by re-
maining open until the pressure is lowered a few pounds below
the popping point.
Safety Valves
533
What is the chief application of pop safety valves?
On locomotives.
Ans.
Why does a pop safety valve "pop"?
Ans. In this type of spring valve, the construction is such
that as soon as the valve begins to open, an excess area of the
disc is presented to the escaping steam, hence it suddenly opens
wide.


WAYN
..
ALL
៤៣
Figs. 13 and 14.-American springs for brass and iron pop safety valves.
Fig. 13, round type for brass valves 2 ins. and under; fig. 14, rectangular
type for brass and iron valves 2½ ins. and over.
How is the blowing off pressure regulated on a spring
loaded valve?
Ans. By increasing or decreasing the tension of the spring.
This style of valve always has an adjustable set screw for this
purpose.
What names are given to the pressures at which the valve
opens, and at which it closes?
Ans. The blow off and the blow down pressures respectively.
534
Safety Valves
VALVE.
UHH
FLAT
CONTACT SURFACE
H
!!!!!!!
|||||||
SEAT
Spagn
BEVELED
CONTACT SURFACE
!!!!
Figs. 15 and 16.-Valve and seat with flat and beveled contact surface. For marine use, the beveled type
is the standard and the bevel must be inclined at an angle of 45°. Most engineers think that flat seats are
not allowed for marine use, but this is not correct, for according to Rule 11, 23-Flat seat safety valves may
be used under the formula and table under the heading "Safety Valves" in Rule 11.
What kind of a spring should be used with super-heated steam?
Ans. One with an outside spring, as in fig. 18.
Why?
Ans. Because the high temperature of the super-heated steam would in time
destroy the spring.

Safety Valves
535

TOP LEVER
DROP LEVER PIN
DROP LEVER-
TOP-
SPRING
SPRING WASHER
TOP RING
ADJUSTING RING-
RING PIN
SEAT BUSHING
DRAIN
FEATHER
K-
LINK-
00000
Z
G-
H-
M
RELEASE NUT
TOP LEVER PIN
SEAL
COMPRESSION SCREW
CHECK NUT
SPINDLE
SPRING WASHER
-7
KN
B
с
A W L
E
F
G
H
I
J
KAM Z o
L
N
5
1/2"
1716
55%
5
618
612
18
11
213/16 338
1½
2
278
1/4
41/2
7/8
21/2
11/16
TABLE OF DIMENSIONS
7
2" 21/2" 3"
1715/16 195%
2234
558 58 51€
5
411/16
6
35/8
1/4
5
3/4
21/2
5
71/2
138
41/8
21/2
48
¼
578
7/8
3
5/16
11/16
3/4
7 712
2234
5/16
6
81/4
9
1½ 158
43/4
434
3
3
5
1/4
658
7/8
4
614
15/16
312" 4"
9
51/2
1/4
7¼
1
4
6¼
1516
9
273%
41/2" 6"
27% 425%
68 934
7/16
68
7/16
10311½
12½
134 18 1%
578
58
75%
4
4
81/2
634
¼
1/4-
914 10%
18
1
5
8
7¼ 10
616
1/4
812
1
5
7¼
15/10 15/16 18
10 10 132
D
Fig. 17.-Outside spring pop safety valve for use with super-heated steam. An outside spring valve should
always be used with super-heated steam as the spring is protected from the intense heat of the steam.

1
536
Safety Valves
:
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-OPEN DRAIN
TO WASTE
RECOMMENDED SLIP-JOINT EXHAUST CONNECTION
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Figs. 18 to 20.-Safety valve installation. Safety valves must be connected to the boiler independent of any
other steam connection. They must be attached as close as possible to the boiler without any unnecessary
intervening pipe or fitting. When an intervening pipe or fitting is necessary it must not be longer than the
face to face dimension of the corresponding tee fitting of the same size as the valve inlet and of the same
pressure rating. The safety valve must be installed so as to stand in an upright position with the spindle
vertical. A discharge pipe should be provided for safety valve outlets to protect personnel from injury while
the valve is discharging.

Stationary
How does it work?
Ans. In operation, when the valve begins its opening movement, steam rushes into
the pop chamber and suddenly acts on the excess area, thus quickly accelerating the
movement of the valve which opens wide with great rapidity.


Safety Valves
537
On a pop safety valve how is the intensity of the "pop"
regulated?


HIGH BACK PRESSURE
IN POP CHAMBER
Mh! 10
ستسلا
WIRE
DRAWING
POP RING HIGH
HIGH BACK PRESSURE
IN POP CHAMBER
LOW BACK PRESSURE
IN POP CHAMBER
alfide
WAP
FULL
OPENING
POP RING LOW
LOW BACK PRESSURE
IN POP CHAMBER
Figs. 21 and 22.-Pop valve with low and high adjustment of pop ring showing
why the blow down or closing pressure is governed by the position of this
ring. In fig. 21 the ring is in high adjustment so that with the valve fully opened
as shown, the opening past the ring is restricted resulting in wire drawing
of the steam with a higher back pressure in the pop chumber than in fig. 22
where the ring is in low adjustment giving free passage for the steam to the
atmosphere. It must be evident that with the adjustment of fig. 21 giving high
back pressure in the pop chamber, the valve will remain open longer and reduce
the boiler pressure to a lower point than with the adjustment of fig. 22, giving
low back pressure in the pop chamber.
538
Safety Valves
Ans. By adjusting the pop ring. See figs. 21 and 22.
What is the main object of the pop ring?
Ans. To regulate the blow down or closing pressure.
When the pop chamber opens to the atmosphere what
two forces tend to keep the valve open?
Ans. The pressure of the steam in the excess area presented
by the pop chamber (the beveled passage way), and the centri-
fugal force caused by the action of the curved pop lip in chang-
ing the direction of the steam.
What is the effect of adjusting the pop ring?
Ans. If the pop ring be screwed down so low that the pop
chamber is open to the atmosphere when the valve is closed,
the valve will not open so suddenly as when it is adjusted to
close the pop chamber when the valve is seated.
What is the main object of the pop ring?
Ans. To regulate the blow down or closing pressure.
What ridiculous requirement is demanded by the Gov-
ernment of an applicant to receive an engineer's license?
Ans. He must be able to determine the weight necessary to
be placed upon the lever of a safety valve with the usual given
data to withstand any given pressure of steam.
What are the so called "Roper Rules"?
Ans. An absurd misnomer.
In the first place Roper made no rules but simply stated the safety
valve equation in its various forms. Don't learn Roper's alleged rules
parrot fashion, but master the safety valve equation.
Safety Valves
539
Principle of the Safety Valve.-When a boiler is in operation
there are four forces acting on a lever safety valve, of which, one
tends to raise the valve off its seat and the other three tend to keep it
closed; when the first force slightly exceeds the sum of the other
three forces, the valve will open and allow the steam to escape.
The four forces just mentioned may be described as follows:
1. The force due to the steam which tends to open the valve;
:
It is equal to the area of the valve in square inches multiplied by the steam
pressure as indicated by the steam gauge.
2. The force due to the weight of the valve and spindle, which
tends to close the valve;

CENTER OF
GRAVITY
Fig. 23. Method of finding the center of gravity of the lever. The center of gravity of the
lever is the point where the bar would be in equilibrium if balanced over a knife edge or any
other support with a sharp corner placed at right angles to the lever, as shown in the figure.
3. The force due to the weight of the lever, which tends to close
the valve;
4. The force due to the weight of the ball, which tends to close
the valve.
These forces act at different distances from a point called the
fulcrum, which corresponds to the point F, in fig. 24 — about which
the lever turns. As indicated in the figure, the four forces are
as follows:
S = total pressure due to the steam tending to raise the valve;
540
Safety Valves
This is equal to the steam pressure indicated by the steam gauge multiplied
by the area of the valve. The area of the valve is equal to its diameter
squared, multiplied by .7854.
V
G
B
=
weight of valve and spindle;
(
"lever;
"ball.
"
The distances at which these forces act are:
distance from fulcrum to center of the valve;
F
"
-V
"
V
g
b distance from fulcrum to the ball.
b
"
I
"
center of gravity of the lever;

G
BERNAM
B
b.
Fig. 24. Lever safety valve with dimensions, etc., necessary in making calculations.
Distance from fulcrum to ball; g, distance fulcrum to center of gravity of lever; v, distance
fulcrum to spindle; F. fulcrum; V, weight of valve and spindle; G, weight of lever; B,
weight of ball.
The weights are measured in pounds, and the distances in inches.
The weight of the lever is considered as acting at its center of gravity
g, distance from the fulcrum.
The center of gravity of the lever is that point where it would be in equili-
brium if balanced over a knife edge or any other support with an edge, as in
fig. 23.
Now, since all of these forces do not act along the axis or central
point of the valve (fig. 24 ), it is necessary to determine the ten-
dency of the several forces to produce rotation of the lever about the
fulcrum F.
Safety Valves
541
In order to determine this, the moments of the several forces
with respect to the fulcrum F must be determined.
In mechanics the moment of a force is a
measure of its effect in producing rotation
about a fixed point.
The moment of a force, with respect to a point, is the product
of the force multiplied by the perpendicular distance from the point
to the direction of the force.
The fixed point corresponding to the fulcrum F,fig. 24 is called the center
of moments, and the horizontal distance, v, g, or b, the lever arm or leverage of
the force.

;·!|!
VALVE AND SPINDLE
MOMENT
Y
||||||||||
CENTER
OF GRAVITY
OF LEVER
STEAM
MOMENT
\\\
BALL
MOMENT
LEVER
MOMENT
!!!!!|||
Fig. 25. Diagram illustrating the four moments
involved in safety valve calculations. One of
these moments called the steam moment which
tends to OPEN the valve; this is resisted by the
other three moments called the valve and
spindle moment, the lever moment, and the
ball moment which tend to CLOSE the valve.
Evidently when the valve is at the point of
blowing off the steam moment=valve and spindle moment+lever moment +ball moment.
Evidently if the steam pressure increase a very small amount sufficient to cause the steam
moment to overcome the friction of the mechanism, the valve will open and blow off.
The moment of the ball Bin fig.24 with respect to the fulcrum F, for
instance, is equal to the weight of the ball multiplied by its distance from F,
that is, moment of the ball =B X bor simply Bb.
The four moments to be considered in solving the safety valve
problem are as follows:
542
Safety Valves
1. Moment due to the steam;
It is equal to the total pressure of the steam acting on the valve multiplied
by the distance from fulcrum to center of valve; that is, in fig. 24 steam
moment =Sv.
2. Moment due to the weight of the valve and spindle;
It is equal to the weight of the valve and spindle multiplied by the distance
from fulcrum to center of valve; that is, valve and spindle moment = Vv.
3. Moment due to the weight of the lever;
It is equal to the weight of the lever multiplied by the distance from the
fulcrum to the center of gravity of the lever; that is, lever moment=Gg.
4. Moment due to the weight of the ball.
It is equal to the weight of the ball multiplied by the distance from the
fulcrum to the ball; that is, ball moment =Bb.
steam
moment
S X v
Now, when the valve is at the point of blowing off, the first
moment which tends to raise the valve will equal the sum of the
other three moments which tend to keep the valve closed; that is:
ball
moment
BX b
}-{
{
valve and
spindle moment +
V X v
Where a
RULE II, 23.-The areas of all safety valves on boilers contracted for or the construction
of which commenced on or after June 1, 1904, shall be determined in accordance with the
following formula and table:
W
Formula: a=.2074 X—
P
area of safety valve, in square inches, per square foot of grate surface.
W=pounds of water evaporated per square foot of grate surface per hour.
absolute pressure per square inch-working gauge pressure +15.
When this calculation results in an odd size of safety valve, use next larger standard size.
P
a=.2074 X
lever
moment>"+
GX g
100
90
EXAMPLE.
Boiler pressure=75 pounds per square inch (gauge).
2 furnaces: Grate surface=2(No.) X5 feet 6 inches (long) X 3 feet (wide)=33 square feet.
Water evaporated per pound of coal-3 pounds.
Coal burned per square foot grate surface per hour-12½ pounds.
Evaporation per square foot grate surface per hour or W,
15-90 lbs. absolute.
From equation (1)
23 cu. ins.
(1)
8×12=100 pounds. P=75+
Therefore area of safety valve-33 X.23-7.59 square inches.
For which the diameter is 3 inches nearly.
NOTE.-See A.S.M.E.
Power Boiler Code
latest Edition,
Safety Valves
543
ENVISS Man
STEAM
MOMENT
42153
384
38%
LBS.
153
153
2 LBS.
10
|
||||||
0 0 1
or simply:
Sv=Vv+Gg+Bb.
This is the safety valve equation with which any problem is easily
solved. In working out an example, the given values are
Fig. 26. Experiment illustrating the safety valve equation. Take a piece of hard wood and cut out
in the shape of a safety valve lever. Pivot it at A, to a fixed point, after having made a notch at B.
the point where the valve spindle acts, and having determined (by method of fig 23.-its center of
gravity C. Get some light weights and attach one at B (say 2 lbs.) and one at D (say 5 lbs.) and
assume the distances AB, AC, and AD to be 4, 10, and 25 inches respectively. Then if a spring
scale be attached to the lever at B, it will be found to require 384 lbs. pull to balance the lever as
weighted assuming that the lever turns very easily about the pivot A. The reason for this is because
the tendency to pull the lever upward by the spring, known as the steam moment measured by the
product 4 X38¼4) is equal to the tendency to pull the lever downward, measured by the other three
forces known as the valve and spindle moment, the lever moment, and the ball moment (measured
by the products 2 X4, 2 X10, and 5 X25 respectively).

11.
OM!
VALVE AND
SPINDLE
MOMENT
STEAM MOMENT - VALVE AND SPINDLE MOMENT + LEVER MOMENT + BALL MOMENT
4 X 384
2 X 10
20
153
2 x 4'
8
BALL MOMENT
WEIGHT OF LEVER 2 LBS
LEVER MOMENT
-25″
+
+
+
+
5 LBS.
5 x 25
125
......
544
Safety Valves
substituted for the letters and the equation solved for the un-
known letter.
Example:-What weight ball must be put on a 3" safety valve so that it
will blow at 100 lbs., if the weight of valve and spindle be 8 lbs., lever, 24 lbs.,
distance of valve from fulcrum 4"; distance of center of gravity from fulcrum
16"; distance from fulcrum to ball 38".
S, the total pressure tending to raise the valve is equal to the steam pressure
multipiled by the area of the valve in square inches = 100Xdiam. Xdiam. X
.7854-100×3×3×.7854=706.9 lbs., say 707 lbs.
Now write out the equation and substitute the values given in the example
and value just found for S, under the proper letters, thus:
38"

4"
:
8 LBS.
*** ale tu ne
multiplying
and adding
16"
24 LBS.
GIVE
VALVE AREA = .7854 x 3 x3
= 707 SQ INS.
C
3"
STEAM PRESSURE 100 LBS.
Fig. 27. Example: To find what weight must be put on the safety valve when the con-
ditions are as indicated in the figure.
Sv
707X4= 8X4
Vv+Gg + Bb
+ 24X16 + BX38
WEIGHT
2,828=32+384+38B
2,828-416+38B
7
Safety Valves
545
The equation must be "solved for B," which means that everything must
be transferred to the left hand side of the equality sign except the B. The
first step then is to get the 416 on the left hand side; to do this, subtract 416
from both sides, thus:
416
2,412 =
38B
As it now stands, 2,412=38B, or in other words, 38B=2,412:
Now, divide both sides by 38, thus:
38B _2,412, hence:
38 38
DUUJULY
B-2,412-63.4 lbs., weight of ball.
38
SPRING
SCALE
RULE II, 23.—Examples continued
Boiler pressure-215 pounds.
29.7
2,828=416+38B
416

A=.2074 X.
6 furnaces: Grate surface=6 (No.) X5 feet 6 inches (long) X3 feet 4 inches (wide)=110
square feet.
Water evaporated per pound coal-10 pounds.
Coal burned per square foot grate surface per hour 30 pounds.
Evaporation per square foot grate surface per hour-10X30-300 pounds.
Hence W=300, P=215+15=230 lbs. absolute.
300
230
Fig. 28. Weighing the force exerted by the
lever; by thus obtaining the downward thrust
due to the lever, the calculation is simplified
as here explained.
.27
Therefore area of safety valve=110×.27=29.7 square inches, which is too large for one
valve. Use two
14.85 square inches. Diameter 43% inches.
2
546
Safety Valves
Simplified Formula.-After weighing with spring scale as
in fig. 28, the forces will be as in fig. 29 from which the equation
is:
Sv=Mv+ Bb
here M, is equal to the sum of the pressure of the lever as indi-
cated on the scale and spring fig. 28, plus the weight of the
valve and spindle; the other letters are as before.
If the weight of the ball, or its distance from the fulcrum be
required, the equation can be still further simplified by letting
M, in fig. 29,, represent the sum of the pressure of the lever as
indicated on the spring scale plus the weight of the valve and
spindle, subtracted from the total pressure of the steam on the
valve. The equation then becomes
F
V
Σ
Mv - Bb
b
Leisur
S

B
Fig. 29.-Lever safety valve with dimensions, etc., necessary in making. calculations where
the thrust due to the lever is determined by a spring balance as in fig. 28. b, distance ful-
crum to ball; v, distance fulcrum to valve, M=S-L, that is, the total pressure due to the
steam tending to raise the valve, less the downward thrust due to the lever as inĝasured in
fig. 28 ; F, fulcrum; B, weight of ball.
Draught
547

_DIAPHRAGM
LIGHT HOT AIR
U TUBE
HEAVY COLD AIR
CHAPTER 32
Draught
Define draught?
Ans. A current of air.
What causes draught?
Ans. A thermal upset in which tempera-
ture difference changes the weight of air.
That is, air when heated expands and thus
becomes lighter, destroying equilibrium.
What is the object of a chimney?
Ans. To create draught.
Fig. 1.-Action of hot gases in a chimney; the cause of draught. For an
actual chimney the draught or difference of pressure inside and outside the
chimney may be shown by a U tube partially filled with water, and having one
end connected to the inside of the chimney and the other open to the air. The
water rises in the leg connected with the inside of the chimney; the difference
of level measures the draught.
548
Draught
Why does a chimney draw?
Ans. It draws because the hot air in the chimney is lighter
than the surrounding cold atmosphere, which tends to force its
way into the chimney from below in an attempt to restore
equilibrium. See fig. 1.
ने
PASSAGE
H
Upon what does the intensity of the draught depend?
Ans. Upon the height of the chimney, character of the fuel,
design of the furnace, method of firing, etc.


COMBUSTION
BOILER
WALL
ATMOSPHERIC
PRESSURE
TIFT
RUBBER
TUBE
للمسلسل السيد
OPEN
END
PARTIAL
VACUUM
How is draught measured?
Ans. By a draught gauge.
لسلسيليا
BEFORE CONNECTING
AFTER CONNECTING
Figs. 2 and 3.—U type draught gauge, at zero before connecting, and indicat-
ing 2 inches draught after connecting. In reading, since the column. in the
two tubes fall and rise equal distances, take the reading of one leg only and
double it to obtain the draught in inches.
How does air enter a chimney?
Ans. 1, Through the grate bars (primary air supply); 2,
sometimes through special inlet passages between the furnace
and the heating surface (secondary air supply); and 3, in case
of brick settings, through leaks in the setting if there be any.
Draught
549
14
Describe a simple gauge.
Ans. The intensity of draught which is due to the difference
is indicated by a U tube partly filled with water and having
one end connected to the inside of the chimney and the other
end open to atmosphere outside. See figs. 2 and 3.

❤
FORCE OF DRAUGHT BETWEEN FURNACE AND ASH DIT
INCHES OF WATER
1.3
1.2
1.1
6
~
G
นา
4
3
2
0
NOJ ANTHRACITE BUCKWHEA
DO. ANTHRACITE BUCKWHEAT)
ANTHRACITE
MD. PA, VA & W VA SEMI-BITUMINOUS
ALA. KY/PA TENA. BITUMINOUS
ILL. IND. &/KAN/ BITUMINOUS
10
15
20
25
30
35
40
45
5
POUNDS OF COAL BURNED PER SQ. FT. OF GRATE SURFACE PER HOUR
Fig. 4. Draught curves showing draught required for various fuels. It is impossi-
ble to give the total draught required for efficient combustion of any given fuel
because the total draught required for any particular installation depends upon
quite a number of items, such as type of boiler, rate of combustion, quality of
coal, thickness of fire bed, area and arrangement of breeching, height and cross
sectional area of stack, etc. and these factors are variable.
How does the gauge operate to measure the draught?
Ans. The water rises in the leg connected with the inside of
the chimney and recedes in the other leg. The difference in
levels measures the draught.
550
Draught
How is draught measured?
Ans. In fractional inches of water.
Name two kinds of draught.
Ans. Natural and mechanical or forced.

JET RING
VORTEX
How is mechanical draught
produced?
Ans. By a blower.
Mention one advantage of
forced draught.
Ans. Inferior (cheap) fuels
may be substituted for the
higher grade coals.
Why must forced draught be
used with these cheap fuels?

Ans. They require for their
combustion an intensity and
concentration of draught which
a chimney, unless of great
height, is incapable of producing.
Figs. 5 and 6.-Vortex type jet blower. The jet ring is placed at the large end
of a cone shaped tube. The jet holes in the jet ring are drilled at angles such
that the steam forms a gyratory motion in the tube, thus producing a vaccum.
Draught
551
What are the various methods of producing mechanical
draught?
Ans. 1, Steam jets; 2, pressure in the ash pit (forced draught);
3, blower in the stack (induced draught); 4, combination of
forced and induced draught.
What may be said in favor of steam jets?
Ans. Not much-they are a wasteful makeshift. See figs.
5 to 8.
PC
·STACK-
-JET BLOWER.
JA, B.

1

Figs. 7 and 8.—Ordinary steam jet blower made from wrought pipe. The pipe
is bent to circular form and the end closed with a cap. For maximum efficiency,
the holes should be drilled at a slight angle with the sides of the stack, so as to
project the steam alternately outward and inward, as at A and B, fig. 8.
What conditions favor the use of jets?
Ans. Intermittent use as a help to carry an occasional peak
load. They are used intermittently on locomotives preparatory
to running.
How much draught can be produced with a jet?
Ans. When placed in the stack, maximum draught is about
3/4 in.
552
Draught


BULKHEAD
→→
88 82 82


Figs. 9 to 12.-Installation of forced draught system to old boiler plant.*

FUNNEL
TO
FLOOR
CENTRIFUGAL AIR PUMP
DECK
BOILER
A
BULKHEADS
AIR
LOCK
DOOR
Fig. 13.-Closed stokehold method of forced draught as ordinarily used in
marine practice. The boilers are placed in an air tight room and air under pres-
sure is supplied by a centrifugal fan. In some cases the ash pan of the boiler
is made air tight and connected direct to the outlet of the fan.
Draught
553
What do you understand by the term forced draught?
Ans. A system in which air under pressure is introduced into
an air tight ash pit and forced through the bed of fuel on the
grate. See figs. 9 to 12.
Describe the closed stokehold system of draught used in
marine service, as shown in fig. 13.
Ans. In this system the boiler room is entirely enclosed and
provided with air locks for the passage of the attendants. The

5
I
MALA HA
DXHAUST TO ASK PYT, OR TO
HEATING SYSTEM! WITH CHECK VALIR.
Fig. 14.-Wing turbine and fan forced draught system showing side wall installa-
tion. The automatic pressure regulator 4, controls the balanced valve 3, con-
trolling all blowers; the by pass 5, make combustion continuous.
554
Draught
L
fans discharge into the boiler room and maintain a static
pressure of from 34 to 3 ins. of water according to requirements.
Why is forced draught employed in marine practice in-
stead of induced draught?
Ans. Because the apparatus is lighter.
What are the essentials of induced draught?
Ans. In this system a fan is located in the smoke flue and

TURBINE
3
SIDE WALL
-FAN
GRATE
#
Fig. 15.-Standard installation of turbine blower. The blower forces air into an air
tight ash pit. It is most easily installed in the side wall of the ash pit, and gener-
ally projects 5 to 10 ins. from the wall, according to size, but it may be set flush
with the wall. When the side wall is not accessible, the blower may be placed
in the rear wall, and made to communicate with the ash pit through a brick
covered sheet iron duct leading through the combustion chamber and the
bridge wall. Again it may be placed in the front wall or by the ash pit door.
which in operation draws or "pumps" the gases through the
furnace and discharges them into the delivery stack.
What is the application of induced draught?
Ans. It is adapted to all kinds of fuel and furnace except
Draught
555
those in which underfeed stokers or hollow blast grates are
employed.
What is the most important advantage of induced
draught?
Ans. It permits the use of larger economizers.
How much coal ordinarily is burned with natural
draught?
Ans. From 10 to 25 lbs. per sq. ft. of grate per hour.

-
Fig. 16.-Graham special trunk piston transfer expansion steam jacketed os-
cillating engine* direct connected to blower. This method of jacketing is such
that the steam passing through the cylinder is brought into more intimate con-
tact with the jacketed walls than in any other system, thus permitting a high
degree of expansion without condensation. The value of steam jackets and the
proper condition under which they should be used are not generally understood.
The author's claim that this engine is as economical as the ordinary compound
is based upon his investigation of steam jackets and test data especially that
of Donkin.
*NOTE.-A sectional view of this engine showing features of construction is
shown in Audels Engineers and Mechanics Guide Vol. 2, Page 687.
556
Draught
How much with forced draught?
Ans. Usually from 40 to 60 or more lbs. per sq. ft. of grate
per hour.
Mechanical Stokers
557
CHAPTER 33
Mechanical Stokers
What is a mechanical stoker?
Ans. A device constructed to automatically feed fuel to a
furnace.
What is the advantage of a mechanical stoker?
Ans. Its use results in more efficient combustion owing to
constant instead of intermittent firing.
What is the trouble with hand firing?
Ans. The frequent opening of the doors allows a large excess
of air to enter which chills the flame and the dumping of a
quantity of fuel at each firing results in a smoke period until
normal combustion conditions are restored.
Name the principal types of mechanical stokers.
Ans. 1, Over feed; 2, under feed; 3, rotary or sprinkler feed;
4, chain or travelling grate feed.
What are the two types of over feed stoker?
Ans. The front feed and the side feed types.
:
558
Mechanical Stokers

• pop-pood
..>
......
Fig. 1.-Typical inclined chain grate stoker applied to tubular boiler, and ratchet ash drags which are recom-
mended when ash storage pit under rear of chain grates is impossible or inaccessible. An accumulating pit
for storage of ashes, sealed by trap door. The ash drag consists of angle members riveted to a series of endless
sprocket chains riding sprockets on front and rear shafts. Tension take up is provided for the front sprocket
shaft. A relief spring is placed in the connection between the eccentric on the line shaft driving stokers
and the ratchet mechanism driving the front sprocket shaft of ash drag.
Mechanical Stokers
559
Describe a typical over feed stoker of the front feed type.
Ans. It has a step grate consisting of a series of stepped
grate bars slightly inclined from the horizontal, and a dumping
grate at the bottom which receives and discharges the ashes.
Describe its operation.
Ans. The grate bars are given a slow rocking or swaying
motion by means of a small engine or motor. This motion
gradually carries the fuel as it is burned toward the rear and
bottom of the furnace. There is a flat ash table at the bottom
of the inclined grates.
What happens during the process of combustion?
Ans. The fuel is coked on the upper portion of the grates and
the volatile gases, driven off in this process, are ignited and
burned in their passage over the bed of burning carbon lower
on the grates.
What are the features of the side type over the front
feed stoker?
Ans. Fuel is fed from the sides of the furnace for its full
length or on the upper part of the grates which are inclined
toward the center.
How are the inclined grates moved?
Ans. By rocking bars.
What does the motion do?
Ans. The fuel is gradually carried on to the bottom and
center of the furnace as combustion proceeds, where a clinker
breaker grinds out and removes the refuse.
5600
Mechanical Stokers
ROCKER PLATES FOR
AGITATING CRUSHING
AND DISCHARGING ASMES
YNN
8002
WWK
2220%%
HID
37.7%
HUA
www.
Zola
www
74770
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WAL
3722
INO
201
2013
WAS
CHA
800.
WI
100
4:22
www
Im
WWW.
KWA
48%
OVERFEED
RECIPROCATING
GRATE BARS
ADJUSTABLE OPENING
FOR CONTINUOUS
DUMPING
Laa
pass
0
DAD
"
UNDERFEED
RECIPROCATING
GRATE BLOCKS
RECIPROCATING RETORT SIDE
BARS CARRYING GRATES AND
ROCKER PLATES
DAMPER FOR REGULATING
AIR FOR OVERFEED
COMBUSTION
SHAFT FOR ADJUSTING
POSITION OF ROCKER PLATES
LIIK
NONKE
SARKIRI
TAIIABIL
ENITITII
ANHAXI
ZDANIIN
AR
SAFETY SHEARING
PIN THROUGH
CONNECTING ROD
RODS FOR OPERATING
RETORT SIDE BARS
AIR CHAMBER ACCESS.
IBLE THROUGH REMOVABLE
FRONT PLATE
SPEED
SHAFT
Fig. 2.-Self-dumping under feed inclined grate stoker. The stoker is a multiple-retort, underfeed stoker with an
incline of 20°. Below the retorts, the grate surface is continuous so as to burn fuel completely before it is pushed
off the ash supporting plates. The distinctive feature of this stoker is that the sides of the retorts reciprocate
relative to the bottoms. This provides a means of moving the fuel uniformly along and out of the retort. It also
provides a moving grate surface on to which the fuel is passed as it leaves the retort. The same movement serves
to push the refuse across the rocker ash dumping plates where it continuously discharges through the adjustable
opening next to the bridge wall. To prevent the possibility of a breakdown due to foreign matter in the fuel,
each plunger connecting rod has a safety device. This safety device consists of a standard 1/2 in. rivet so placed
that it is double sheared when the plunger strikes an obstacle.

Mechanical Stokers
561
For what kind of fuel are over feed stokers adapted?
Ans. For caking coal.
FLAME
}
How is caking prevented?
Ans. The fires ordinarily carried are comparatively thin and
the movement of the grate bars keeps them broken up and
open, thus preventing caking.

FRONT WALL
PROTECTED
AIR
Fig. 3.-Detail of an underfeed link grate stoker. Link grate motion reduces
resistance to air flow by keeping the fuel bed porous. Air flowing through the
grates is not smothered, but is allowed to support combustion by thoroughly
permeating all parts of the fuel bed.
What is an under feed stoker?
Ans. One in which the fuel is fed upward from underneath.

562
Mechanical Stokers
Fig. 4. Single retort link grate stoker designed to produce undulating or wave-like motion. This motion is un-
usually effective in processing the fuel bed to secure thorough permeation of the air and thus higher combustion
efficiency. It makes out of the old practice of periodic hand-slicing a process that is continuous and auto-
matic. Lower coal bills are a direct result. This stoker brings to the average size power plant advantages simi-
lar to those of the modern multiple retort stoker. It is normally applied to boilers ranging in size from about
150 boiler horsepower upward, with capacities up to approximately 40,000 lbs. steam per hour. The stoker
is readily installed under existing boilers with a minimum of excavation or furnace changes. No special tile or
arches are required in the furnace. No basement is required, as ashes may be removed through ash pit doors
in the lower stoker front,
ILA
ww
A
En A

Mechanical Stokers
563
wollady nocl
lovode o dont it no 201
2nd and Chilever
COAL HOPPER
MAIN RAM
DRIVING ENGINE
FLOOR LINE
job tud
lotimi
Toop silt
ADJUSTABLE
SEC. RAM
DRIVING ARM
017
FRONT WALL
SECONDARY AIR PORTS
RETORT THROAT
RETORT SIDE
Fig. 5.-Section through single retort link grate stoker showing parts.
ADJUSTABLE DRIVING BLOCKS
BRIDGE WALL
SECONDARY RAM PLATES
bezom
busc6e off
COMPENSATOR
GRATES
RETORT BOTTOM
ayoda lot/
Hvad foul od
Quie rubb
OC
SECONDARY AIR DUCT
46
30
offs dwonl
IT an A
Loob NOTL
15oroll and
FOODS ons woll
564
Mechanical Stokers
How are they classed with respect to the grates?
Ans. Horizontal and inclined.
How does the horizontal type work?
Ans. The action of a screw or worm carries the fuel back
through a retort, from which it passes upward, as the fuel above
is consumed, the ash being finally deposited on dead plates on
either side of the retort, from which it can be removed.

Jona
Yo
yers.
IMPELLER
SPIRAL
FEED
Fig. 6.—Rotary or sprinkler stoker. In operation the revolving member catches
the coal as it is fed from the hopper and throws or sprinkles it upon the fire,
imitating the operation of a fireman in throwing fuel on the fire with a shovel,
but doing so in a more efficient manner.

Mechanical Stokers
565
apo po po p
bi
Fig. 7.-Typical link grate underfeed stoker. Link grate applications have been made to all types of boilers,
handling a wide variety of steam loads.
566
Mechanical Stokers
Describe the inclined type.
Ans. A piston or ram forces broken coal up through the fire
bars into the fuel bed; tuyere boxes are provided through which
air is forced by a fan, and which are covered by perforated cast
iron blocks. A series of rams are driven at variable speed by
gearing. As the coal drops behind them, it is pushed upward
and backward working to the surface and eventually past the
extension grate to the dump plate, on which hot refuse accumu-
lates to be dumped every three to six hours, depending upon
the rate of working.
How does a rotary or sprinkler stoker work?
Ans. The revolving member catches the coal as it is ted from
the hopper and throws or sprinkles it upon the fire, imitating
the operation of a fireman in throwing fuel on the fire with a
shovel, but doing it in a more efficient manner.
What is a traveling grate or chain stoker?
Ans. A type of over feed stoker consisting of an "endless
grate" composed of short sections of bars passing over sprockets
at the front and rear of the furnace.
How is the coal fed?
Ans. It is fed by gravity onto the forward end of the grates
through suitable hoppers.
How does the grate work?
Ans. The movement of the grate through furnace is con-
tinuous being driven through a worm wheel keyed to the front
sprocket shaft.

Mechanical Stokers
567
BROWNELL
hstgeba Howd
na umepration
Derriaɔak bruk fonon Sell
OTEL
Fig. 8.-Ram type single retort stoker showing hopper, grate, automatic draught, etc. The function of the auto-
matic air volume control is to regulate the amount of air, under varying static pressure, delivered to the fuel
bed so that regardless of the boiler load enough but not too much air is present at all times to produce maxi-
mum combustion efficiency. When once adjusted for a given quality of coal, the automatic air volume control
makes it possible to maintain a constant depth of fuel bed-holes in fuel bed are eliminated and fly ash
reduced to a minimum.

568
Mechanical Stokers
Describe the combustion.
Ans. Fuel is ignited under ignition arches and is carried with
the grate toward the rear of the furnace as its combustion
progresses.
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For what class of fuel is the chain stoker well adapted?
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Fig. 9. Ram type single retort stoker unit drive with cover plates and belt guard
removed. At the end of the crankshaft is shown the ram limit switch which
automatically acts so as to stop the ram at the farthest point in on the feeding
stroke, thus preventing the fire burning back into the hopper when the stoker
is shut down. This switch is adjustable and its operation is such that undue
strain on the motor and other moving parts is eliminated when the mechanism
starts.
Ans. For burning low grades of coal running high in ash and
volatile matter.
Mention one outstanding feature of chain stokers.
Ans. Cleaning of the fire is continuous and automatic hence
no periods occur when smoke will necessarily be produced

Mechanical Stokers
569
Operating Points und W
Hiw gron Under Feed Stokers
1 en A
ut Jusivittue
What are two causes of excessive outage and mainten-
ance? od: lo abas art of navig ad bluode nolinse 16W
Ans. 1, Sustained or frequent overloading of stoker and 2,
operating with insufficient draught. and Jart of 91690 A
Jedt
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Fig. 10. Ram type single retort stoker showing fan side unit drive cover re-
moved from ram light switch.
What precaution should be taken with the retort? W
Ans. Keep fire out of the retort.
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570
Mechanical Stokers
What causes fire in the retort?
Ans. It results from too thin a fuel bed, banking with in-
sufficient fuel or from running with an empty hopper.
What attention should be given to the ends of the grate
bars?
Ans. Operate so that the ends of grate bars adjacent to dump
grates are always covered.
What should be done if ends of bars be bare?
Ans. Speed up stoker until they are covered.
What attention should be given to the fuel?
Ans. Be sure that fuel distributes uniformly over grate.
What precaution should be taken when banking?
Ans. Feed in sufficient fuel.
In case of long banking periods renew supply if necessary.
What should be done when stoker is being shut down?
Ans. Sufficient ash should be fed to keep fire out of retort.
What are the points with respect to depth of fuel bed?
Ans. This is important. If too thin, fire may burn down into
retort and damage retort sides. If too heavy, poor air distribu-
tion will result causing spotty, uneven fire holes in fuel bed,
smoke, and reduced efficiency.
What is the correct depth of fuel bed on a single retort
under feed stoker?

Mechanical Stokers
571
Ans. Correct depth above top of retort may be from 4 to 8
ins., depending upon analysis and burning characteristics of
coal used.
What is the correct depth of fuel bed on a multiple
retort under feed stoker?
Ans. Correct depth of fuel bed above top of tuyeres may be
anywhere from 16 ins. to 20 ins. depending upon analysis and
burning characteristics of coal used.
*****
H
Fig. 11.-Type underfeed stoker designed for homes, apartments, small power or
heating plants. Detail showing circular retort and connections. Sectional tuyeres
conduct air under pressure from the wind box to the fuel bed where a thorough
mixture of air and volatile gases is produced and combustion takes place
under almost ideal conditions. In operation, fuel is carried from the hopper
through a feed tube by means of a rotating worm. Intermittent action of the
worm agitates the fuel bed, prevents arching of coal in the retort and assures
that the incoming air from the tuyeres reaches every part of the fire at all times.
An auxiliary air connection between the feed tube and wind box prevents
gas accumulating in the tube and eliminates any tendency to "smoke back"
through the hopper.
bluorid T
572
Mechanical Stokers
What should be avoided in operating under feed stokers?
Ans. Working of fire should be avoided as much as possible.
If fuel bed require leveling off, light rake or T bar should be used
on surface of fire. Never slice the fire as is done in hand firing by
pushing a bar under the fire and raising it through the fuel bed.
What two instruments are essential for good operation?
Ans. A draught gauge and a CO₂ recorder.
What should be the draught for a single retort stoker?
Ans. Operate with a slight draught just above the fuel bed—
preferably .1 in., not less than .05 in.
What does plus pressure cause?
Ans. Excessive temperature at grates and lower wall areas.
What should be the draught for a multiple retort stoker?
Ans. Always operate with some draught above the fuel bed,
preferably not less than .1 in. The entire furnace however,
should be kept under negative pressure.
How often should a stoker be inspected?
Ans. All accessible parts of a stoker should be inspected
daily. Inaccessible parts should be inspected at least twice
a year.
What should be noted about lubrication?
Ans. The use of the right lubricants at sufficiently frequent
intervals at all points requiring lubrication, is essential if
unnecessary outages and excessive maintenance costs are to
be avoided.
There should be a definite schedule for lubrication, regularly ad-
hered to.

Mechanical Stokers
573
CLEAN-OUT
PIPE
AIR DUCT
OPENING
TUYERES
RETORT
COAL FEED
HOUSING
CLEAN-OUT PIPE
PLATE
SHEAR PLATE
HOUSING
brig b
COAL FEED SCREW
SHEAVE
FIRE TROL
Fig. 12. Single (square) tuyere stoker with worm feed. View with names of parts.
COVER
& BR
HOPPER
MOTOR WITH
ELECTRICAL OVERLOAD
PROTECTION
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FAN
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574
Mechanical Stokers
Operating Points on Chain and
Traveling Grate Stokers
What is the difference between a traveling grate and a
chain stoker?
Ans. The traveling grate stoker differs in structural design
from the chain grate stokers but functionally it is the same.
How is the correct fuel bed thickness, grate speed and
air pressure determined?
Ans. By experimental operation.
How about the supply of coal to the hopper?
Ans. Keep hopper not less than half full.
Wherever possible use mechanically operated swinging spout travel-
ing lorry or non-segregating spreader chutes.
What happens if hot ashes be allowed to gather close to
rear of stoker?
Ans. They may cause warping of grate surface and rear shaft.
What precaution should be taken in banking?
Ans. Never bank a hot fire, always burn down first.
What are the points relating to draught?
Ans. In general the same as for under feed stokers. A proper
supply of air should be maintained at all times.
What attention should be given to the grate?
Ans. Distorted bars or rods may cause extensive damage.
How about worn grate bar ends, etc.?
Mechanical Stokers
575
Ans. Badly worn grate bar ends and driving chains, burned
ledge plates or the combination of these conditions, can cause
excessive air leakage along the grate line.
What is the result of this condition?
Ans. The resulting "blow torch" action is very destructive
to parts in the area.
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How may the life of chains be prolonged?
Ans. By reversing them when badly worn.
Fig. 13. Detail of multiple mechanical pneumatic spreader stoker. The theory
of the spreader stoker is not new. Originally developed many years ago in a
search for a better way to burn coal in industrial boiler furnaces, it is based
upon the idea of spreading coal over a fire in such a way that the larger pieces
are distributed over a grate, while the finer particles burn in suspension. This
theory utilizes the best features of both stoker and pulverized coal burner
operation to burn coal like oil. This stoker mechanically carries the coal into
the furnace and then sprays the fines into suspension while spreading the
larger pieces of coal uniformly over the grates.
*


576
Mechanical Stokers
B
D
endents to e
E
AIR
DUCT
G
BRAN AVANTIVIVI KARAKH
MAA
Fig. 14. Sectional view of multiple mechanical pneumatic spreader stoker. B, large coal hopper capacity; C,
coal agitator; D, coal feed ratchets; E, over fire air control; F, ignition zone; G, grate bars; H, fire over fire.
Mechanical Stokers
577
Operating Points on
Spreader or Sprinkler Stoker
A
What are the two main causes of excessive outage and
maintenance?
Ans. Sustained or frequent overloading of stoker and oper-
ating with insufficient draught resulting in positive furnace
pressure.
Top View showing Multiple Feeders

Fig. 15.-Plan view showing detail of hopper and multiple feeders of mechanical
pneumatic multiple spreader stoker. A, screw feed.

578
Mechanical Stokers
How should the fuel bed be carried?
Ans. Keep it level and thin with little more than a minute's
supply of coal on the grate.
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obseq2
How can this be checked?
Ans. Easily. By shutting off the coal feed with the forced
draught on-the fire should be ready to dump in about one
minute.
Fig. 16. Detail of feeder of mechanical pneumatic multiple feeder spreader
stoker showing feed screws and coal agitators which permit the use of any
coal up to 1½ in. in size, regardless of moisture content, assuring steady
flow of coal to the furnace.
What happens with a heavy fire?
Ans. A heavy fire will smoke and form clinkers. Clinkers fre-
quently cause burned and broken grate sections.
Mechanical Stokers
579
What adjustments are made for an even flow over the
entire grate?
Ans. Adjust distributor speed and circular tray.
What happens with a heavy fire at the bridge wall?
Ans. It will not only form clinkers, but will cause excessive
erosion of brick work.
What happens with a heavy fire at the front?
Ans. It tends to overheat the arch, press and distributing
mechanism and may injure the stoker front.
What should be done when character of fuel is changed
in type, size, or moisture content?
Ans. Always check feeder speed adjustment. Adjust air sup-
ply to suit every change in fuel supply.
What size lumps of coal should be used?
Ans. 34 in. to 14 in.-not over.
What is the objection to using the coarser sizes?
Ans. They cause excessive wear on feeder and distributor
mechanism and tend to overload and clinker the fuel bed.
How about cleaning?
Ans. Clean fires and ash pits at regular intervals, preferably
twice each shift.
This keeps fires in good condition ready to handle load swings.
What happens with accumulated refuse in ash pit?
Ans. It may cause damage to grates and grate mechanism.
580
Mechanical Stokers
What should be done when banking a spreader stoker
fired unit?
Ans. Be sure to leave a layer of ash in the grate to protect
it. Cut down on supply, reduce distributor speed and feed in
coal for banking on front end of stoker only. Then cut off
forced draught and stoker feed. Maintain slight draught over
fire.
What draught should be carried?
Ans. In general the same as for single retort under feed
stokers.
What precaution should be taken with respect to shear
key?
Ans. Use only recommended shear key.
Why?
Ans. The substitution of other material may result in over-
loading or breakage of stoker mechanism.
Special Instructions
for Spreader or Sprinkler Stoker
1. How to start the fire.
When starting up a new installation, it is well to start with a
wood fire or a slow coal fire to dry out the brick or plastic lining
of the firebox. When ready for operation, the fire is started in
the following manner:
Mechanical Stokers
581
First, the coal feed is turned on at the control panel, along with the
coal blower. (The forced draft fan is not turned on.) After about an inch
thick layer of coal has been distributed over the grate, both coal feed
and coal blower are stopped and a wood fire is built on top of the fuel
bed. The forced draft is then started and, after a short interval, the coal
feed and coal blower are also started. All of the switches on the control
panel are then set to "automatic" and the stoker is allowed to run under
the direction of the pressure control or combustion control, as the case
may be.
2. How to bank the fire.
When shutting down over night, the fire may be banked by
placing four or five shovels of coal inside each fire door.
Coal feed, coal blower and forced draft fan are all shut off, and the
stack damper is closed. This will conserve the furnce heat and simplify
starting up again next morning.
When ready to start operations again, the coal piled up inside the
doors is spread out with a hoe, the stack damper is opened, and the
stoker started up. The coal remaining from the banked fire along with
the heat from the refractory lining of the furnace should be enough to
cause instant ignition of the fresh coal being fed into the furnace by the
stoker and it is possible to get up steam pressure quickly by this method..
3. Regulation and Drafts.
Stoker equipment is supplied either for intermittent operation
(governed by a pressure switch) or modulating (full floating)
operation (governed by a combustion control system and vari-
able speed drive on the stoker coal feed).
With intermittent operation the pressure switch is set at the desired
operating pressure. The stoker then starts when the pressure drops be-
low this point and stops when the pressure reaches a point a few pounds
above this. A time switch is also supplied to maintain a fire during
periods of light load when the pressure switch may possibly not call for
the operation of the stoker for a length of time sufficiently long for the
fire to go out. In such a case the time switch will cut in every three min-
utes and will operate the stoker for adjustable periods up to 1½ min-
utes, permitting the feeding of just enough coal to keep the fire going
582
Mechanical Stokers
When using an electric damper regulator along with this type
of operation, its action is as follows:
In operation, when the pressure switch on the control panel closes
due to a drop in steam pressure below the predetermined point, the
damper regulator motor starts, opening the stack damper. Ten seconds
later, after damper is fully opened, switches on control panel start coal
feed, coal blower, and forced draft fan motors.
When steam pressure reaches desired point, pressure switch
opens, stopping coal feed, coal blower, and forced draft fan
motors and starting damper regulator motor.
This runs for ten seconds, closing stack damper and conserving fur-
nace heat, thus saving much valuable fuel. Notice that there is no
possibility of stoker or forced draught fan starting before damper is
wide open-thus there is no possibility of "flare back" through the
fire doors.
When the stoker is governed by an automatic combustion
control system the power cylinder of the master regulator is
connected up to the variable speed pulley platform of the stoker,
thus changing the speed of the coal feed drive according to the
demand for steam.
It is also connected to the control louvres of the forced draught fan
so that the amount of air fed under the grates is in proportion to the
amount of coal being burned. The proper overfire draught is usually
maintained by means of an overfire air regulator which maintains a
fixed draught setting in the fire box by adjusting the boiler damper.
The maintenance of proper undergrate pressure and overfire
draft is extremely important if efficient operation is to be
obtained.
The louvres of the forced draught fan should be adjusted so that the
pressure in the plenum chamber under the grates will be between 0.3
and 0.5 of an inch. The overfire draught should be set at between 0.03
and 0.06 of an inch by means of the boiler damper. These settings are
to be made when the stoker is operating at normal load. Once set, the
Mechanical Stokers
583
stoker will maintain approximately these conditions because the design
of the grates is such that the grates themselves furnish about eighty per
cent of the total resistance of the grates and fuel bed; thus any change
in thickness and consequent increase in resistance through the fuel bed
means little in the overall resistance of grates and fuel bed.
For most efficient operation of stoker equipment, the mini-
mum equipment required is:
1. Draught gauge having a scale capable of registering from zero
to at least 0.1 inch of water.
2. Pressure gauge having a scale capable of registering from zero to
at least 1.0 inch of water for each section of the plenum chamber. On
multi-section wind box installations, one gauge may be used with piping
and valves which makes it possible to switch from one section to the
other.
The coal feeding capacity of each individual feed screw may
be easily changed by merely changing the setting of the control
knob at the side of the feeder ratchet.
This knob, shown at D, in fig. 14, is pulled out and turned to the
desired setting. Each number on the dial refers to the number of teeth
that the ratchet will pick up at each stroke of the drive bar; thus, the
setting may be arranged so that the ratchet pawl picks up from 2 to
8 teeth per stroke.
4. How to clean fires with the Fyr-feeder.
When cleaning the fire with a single section grate, that is, a
grate that does not have any division plates or dampers in the
plenum chamber, the proper procedure is as follows:
First, stop the coal feed on the feeders on one side of the stoker by
throwing back the ratchet pawls on these feeders as shown in fig. 16.
Allow the machine to operate for about three to five minutes,
permitting all of the coal on this side of the grate to be burned out. Then
open the fire door and, with a hoe, weed out the ash from this side
right down to the bare grate. Then close the door and throw the ratchet
pawls back down. carting the coal feed to this side of the grate again.
584
Mechanical Stokers
The heat from the fire on the other side of the grate, plus the heat
from the refractory walls, will cause quick ignition of the fresh coal
being fed into the firebox.
It is not necessary to spread or work the fire in any way. If the job is
equipped with dumping grates, the procedure is the same as outlined
above except that the grates are dumped after the coal has been burnea
down, instead of cleaning with a hoe.
When cleaning the fire on a multi-section grate, that is, one
having two or more sections in the plenum chamber, the coal
feed is stopped on the feeders opposite one section of the grate.
After a few minutes, the forced draught air to this section is also cut
off by means of the plenum chamber damper control rod which pro-
trudes through the front furnace wall. The first section of the grate is
then either cleaned with a hoe, or dumper, as the case may be, and the
coal feed and forced draft air again turned on in this section. The same
process is then repeated for the other sections.
The cleaning of fires is simple for it should not be necessary
to use any tool but a light hoe.
There should be no need for working the fire in any way. It is well to
clean the fire when the thickness of the fuel bed (fire bed plus ash)
reaches a height of approximately four or five inches. The table which
follows indicates the recommended cleaning frequency for various coal
burning rates and for coals with different ash contents.
More Steam Per Pound of Coal
NOTE.—The basic reason for the wide adoption of mechanical firing has been
the need for higher combustion efficiency. To-day it is more important than ever
before to get maximum steam power for every pound of coal fired. The common
aim of all builders and operators of coal-burning equipment is to obtain ore
heat from a given amount of fuel. Various manufacturers have approached this
problem from different angles and with different results. Consequently, some
firing units are better than others. In seeking the best over-all operating economy,
a vital need is the equipment design which most effectively carries out the basic
principle of high combustion efficiency. What is this principle? It is the intimate
mixture of coal and air. The fundamental problem of all firing is to bring together
the right amount of coal and the right amount of air at the right time, so that
all combustible elements are burned. The most efficient stoker, then may be
defined as the one in which this intimate mixture of coal and air takes place con-
tinuously and most effectively.

Mechanical Stokers
585
Linval gel als moi la sant
THERMOSTAT
ELECTRIC CONTROL
WORM FEED
momofua
Fig. 17.-1. F. screw underfeed automatic stoker. View showing stoker, heater, piping and automatics.

586
Mechanical Stokers
eventetup bro pri
Fig. 18.-I.F. screw underfeed automatic stoker volumeter or automatic air
adjuster.
Fig. 19.-I. F. screw underfeed screw underfeed stoker safety shear pin. The
shear pin serves to disconnect the motor fan feed in case any foreign matter
such as a piece of iron clog the feed.
Pulverized Coal Systems
587
CHAPTER 34
Pulverized Coal
Systems
It is agreed by all those who are familiar with combustion
that radiant heat is most desirable and that it is about eight
times as good as heat by convection in the combustion chambers.
This is the important reason for pulverized fuel as its luminous
flame gives off radiant heat.
What is radiant heat?
Ans. As an example, the sun gives off pure radiant heat, but
when the sun is beclouded the heat transfer is materially re-
duced. Therefore, the greatest care should be taken to prevent
smoke in a furnace which obscures the radiant heat and retards
the proper transfer of heat in the furnace.
In a furnace what part of the heating surface absorbs
radiant heat?
Ans. Every part of the surface exposed to the light of the
luminous or radiant flame.
The superior efficiency of a radiant flame in a furnace box is obvious,
that is, it crams it "full of heat."
How has the design of boiler furnaces been influenced
by radiant heat?
588
Pulverized Coal Systems
Ans. In power plant work, this is strikingly demonstrated
by the increasing use of furnace water walls and by rebaffling
arrangements to expose a greater amount of heating surface
in the furnace to the radiant heat such as is obtained by the
use of pulverized coal.
Give another reason for the use of water walls?
Ans. They are for the protection of refractory walls made
necessary by the use of pulverized coal with its radiant heat
and high combustion rates.
Combustion rates of 40,000 to 200,000 B.t.u. per cu. ft. per hour
have been attained without difficulty with all refractory surfaces pro-
tected by water walls.
What is the nature of a non-radiant or “blue flame"
such as a gas stove flame?
Ans. It does not radiate heat waves but must be in actual
contact with a surface to transfer heat efficiently. Moreover,
it delivers very little heat except to the surface it is touching.
Points on Combustion.-It is conceded by all that gas is
the best fuel for obtaining nearly perfect combustion. Accord-
ingly, the nearer we approach the gaseous state in coal pul-
verization, the nearer we approach complete combustion. It
must be evident, therefore, that coarse coal is not efficient in
either a small or a large furnace.
In the combustion of coal there exists, on the surface of the hot car-
bon, a film of gas through which the oxygen must pass before it can
react. The rate of combustion, and therefore, the efficiency of the fur-
nace, depends upon the rate at which oxygen diffuses through this
stationary gas film which is over the carbon surface. It is also evident
that the finer the pulverization, the greater the number of carbon
surfaces exposed to the action of the oxygen, thus producing complete
combustion in the least time.
Pulverized Coal Systems
589
What is necessary to secure complete combustion?
Ans. All of the carbon must combine with the oxygen before
the coal particles are drawn by gravity out of the path of the
flame.
The grinding of a cubic inch of coal to a fineness of which 60 to 75
per cent will pass through a 300 mesh sieve, increases the surface
exposure from one piece, having six surfaces of one inch each, to more
than 27,000,000 particles with innumerable sides or surfaces.
Careful estimates indicate that the area of the surface exposed is
beyond 5,000 square inches. Therefore, by fine pulverization we closely
approach a true gaseous state, and thus secure complete combustion.
The advantage of using coal when pulverized to an impalpable
powder and the possibility of using the inferior grades that could not
otherwise be used has brought out many ideas as to the best means
of utilizing pulverized fuel.
Pulverized Coal Systems.-The firing of coal in pulverized
form involves primarily the functions of:
1. Pulverization.
2. Mixing of coal and air.
3. Delivery of coal-air mixture to burners.
4. Combustion.
The equipment for performing these diverse functions is
commonly referred to as a pulverized coal system.
Three methods of firing are available: 1, horizontal; 2, tan-
gential (also known as "corner"); 3, vertical.
Oil or gas may be used as supplementary fuel or in combina-
tion with coal.
What is important in any application?
Ans. The furnace design.

590
Pulverized Coal Systems
Furnaces may provide for the discharge of ash in either dry
or fluid form. They should be water cooled to assure continuity
of operation as well as minimum maintenance. Water cooled
furnaces also add substantially to the steam generating capac-
ity or permit a smaller amount of convection evaporative
surface for a given output.
30
Fig. 1.-Interior construction of bowl mill. tudi sonu Tan
Pulverized Coal Systems
591
Pulverizers.-The pulverization of materials may be accom-
plished by various types of pulverizers or mills, such as:
1. Attrition mill (bowl).
2. Impact mill.
3. Combined impact and attrition mill.
Attrition (bowl) Pulverizer
Describe the bowl mill operation.
Ans. Crushed coal from the rotary feeder falls to the center
of the bowl, which is keyed to the vertical shaft, and as the
bowl revolves, the coal is thrown between the grinding surface
of the bowl and the rollers, which are carried by journals
attached to the mill housing. During pulverization, the fine
particles rise to the surface and are picked up by the current
of air which is caused to pass upward around the bowl by the
action of the exhauster. The coal and air mixture enters the
classifier, where the direction of flow is abruptly changed,
thereby rejecting the heavy pieces which are returned to the
bowl for further grinding. The remaining mixture with coal of
the desired fineness, passes on through the exhauster and piping
to the burners. See fig. 1.
How is the air supplied?
Ans. The air supply to the mill may be taken directly from
the boiler room or may be supplied through a duct from an
air preheater.
Note.-Tramp iron, Etc.-In considering the various methods for the reduc-
tion of materials, it must be borne in mind that metallic substances will be found
in all materials such as pieces of drill steel, bolts, nuts, etc., and that even where
magnetic separators are used for attracting the metallic substances, the magnet
is under the material flowing to the mill and the steel is usually on top. Further-
more, the magnet has no effect on manganese steel, copper, brass, wood, stone,
rock and similar materials. As the magnet cannot pick up these materials, or all
the pieces of steel, it is important to use a machine in which magnets are unneces-
sary, and so constructed, that it will not be damaged or wrecked if such foreign
materials reach the moving parts.

592
Pulverized Coal Systems
J
6
A
Fig. 2.-Classifier with converter head showing means for fineness regulation.
Pulverized Coal Systems
593
Ans. All foreign matter, although supposed to be removed
by screens and magnetic separator, sometimes pass through
the feeder to the mill.
Any tramp iron that does not reach the mill is ordinarily discharged.
by centrifugal force over the rim of the bowl into the air chamber where
revolving sweeps discharge it through an opening to a spout with a
counter-weighted door.
What drive is used?
Ans. The drive unit may be either a constant speed motor
or a steam turbine with a reduction gear. Its shaft is coupled
to the horizontal mill shaft which carries the drive worm gear.
Describe the grinding elements.
Ans. They consist of a cast steel bowl, which revolves on
the vertical shaft, and rollers, which revolve on journals
attached to the mill housing as shown in fig. 1.
At no time, even after the mill is empty, do the rollers touch the
replaceable steel grinding ring in the bowl.
Describe the operation of the classifier.
Ans. Fig 2 shows the classifier. After sufficient pulverization,
the mixture of coal and air passes through openings in the
outer part of the top plate of the grinding chamber into the
classifier where it passes through openings equipped with de-
flectors or vanes. These are adjustable from the outside for
variation of the fineness. A spiral on the inner cone of the
classifier facilitates the return of oversized particles to the
bowl through an opening in the bottom of the classifier. A
cone suspended above this opening tends to build up pressure
at this point and aids in rejecting the coarse particles.
Adjustment of the height of this cone in the classifier can be made
conveniently on the outside of the mill. The classifier and pipe con-

594
Pulverized Coal Systems
nections are designed to allow replacement of rolls and grinding ring
without disconnecting the piping.
8 5090gain bne anos
lime on bool sib
d
What duty is performed by the exhauster?
vielse than 10 Tim.rld.
Ans. The exhauster is shown in fig. 3. In operation, the
pulverized coal is blown through the burner supply pipes by
the exhauster, which is a steel plate fan enclosed in a cast iron
housing with replaceable liners. It may be coupled to the op-
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Fig. 3.—Mill exhauster showing fan blades and renewable liners.
Iwod
posite end of the horizontal worm shaft from the drive unit, or
it may be separately driven in the most convenient location.
Where there is more than one burner per mill, distibutors, as in
fig. 4, are required to equalize the flow of coal.
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dongen

Pulverized Coal Systems
595
Impact Mill
What are the essential elements of the impact mill?
Ans. A rotor with swinging hammers arranged to rotate
inside a suitable casing.
Fig. 4.-Distributor for providing uniform supply of pulverized coal to two pipe
lines.
For what service is the impact mill suited?
Ans. It is well suited for use with all coals except those
which have excessive amounts of iron pyrites or other highly
abrasive material.

596
Pulverized Coal System
Describe the rotor.
IliM tongmi
Ans. The drive shaft of the mill extends through the pul-
verizing chamber and has keyed to it a series of steel discs.
Manganese steel hammers are pivoted to rods which pass
through the discs near their outer edges. Swinging hammers
are used to allow for the passage of foreign matter into the
tramp iron pocket without damage to the mill parts. See
details in fig. 5.
Fig. 5.-Impact mill with cover removed to show hammers, fineness regulator
and exhauster blades.
How is the fineness regulated?
Ans. The smaller mills have a set of adjustable blades in
the conical section between the mill chamber and the fan,
which regulate the fineness of the coal. The larger mills are
equipped with classifiers similar to those on the bowl mills.
The action of either the adjustable blades or the classifier

Pulverized Coal Systems
597
causes the larger particles of coal to be returned for further
pulverization.
day mal
twom
ed
e Al 21
Describe the feeder for bowl and impact mills.
Ans. Fig. 6 shows a separate feeder. In operation, coal enters
the feeder hopper from the crushed coal bunker and down a
spout through the shut off gate at the top of the hopper. A
megah hoen
3 la hoboot of
mycal an
Fig. 6.-Separate feeder with adjustable speed mechanism. Bed plate provides
mounting for constant speed motor which is belt connected.
spider keyed to the drive shaft of the feeder extends through a
cylindrical cast iron core, which forms the base of the feed roll.
Plates fastened to the spider revolve around the stationary
cylindrical base so that the coal from each pocket is emptied
into the mill with an overshot discharge. modus m

598
Pulverized Coal Systems
A hinged plate, held in place by spring pressure, limits the amount
of discharge from each pocket, but allows passage of foreign material
which might otherwise cause damage to the feeder. Constant volumetric
feeding capacity is assured by these features as well as by close clear-
ances and smooth interior surfaces of the feeder body.
How about the feeder drive?
Ans. The following methods of driving the feeder may be
used, depending upon the conditions:
1. Adjustable speed d.c. motor belted to gear box with chain drive
to feeder shaft.
Fig. 7.-Sectional view through hollow feed roll showing means for admission
of air.
2. Constant speed a.c. motor with adjustable cone pulley mechanical
speed changing drive connected to feeder shaft.
3. Constant speed a.c. motor belted to gear reducer and speed changer
with free wheeling clutches on the feeder shaft.
formed
In any of these methods, the feeder speed may be manually
adjusted or an automatic control system may be used.

Pulverized Coal Systems
599
Rini wore Nim en lo
to volnos Heronit nalbee 100-or
Pressure Lubrication
to Main Bearings
Oil Tank with Filter
Disc Feeder
KENNEDY VAN SAUN
NEW YORK
A SILENT Air Swept Tube Mill equipped
with sound absorbing elements, forced feed
lubrication through the bearings. The
oil passing through the oil filter to a
tank from which it is pumped through
the circulating system.
Worm Drive
Oil Pump
Timken Roller Bearings
Running in Oil
Cooling Coil
Fig. 8.-Air swept tube combined impact and attrition mill. View showing construction details, motor drive, etc.
600
Pulverized Coal Systems
CONSTANT SPEED REVOLVING PORTION OF
PULVERIZER, IN WHICH FUEL IS PULVERIZED
BY THE CASCADING OF FORGED STEEL BALLS.
VARIABLE SPEED Disc Feeder.
USA, VANESSA
HNLET FOR PREHEATED AIR
USED FOR THE AIR SWEEPING
OF THE PULVERIZER. APROX 15%
OF TOTAL COMBUSTION AIR USEO
FOR THIS PURPOSE
ROTATION OF
DISCHARGE FROM PRIMARY AIR FAN TO BURNER MADE
UP OF THE PULVERIZED FUEL AND APROX 30% OF
THE AIR REQUIRED FOR COMBUSTION.

INLET FOR PREHEATED CARRIER AIR USED TO
INSURE SUFFICIENT VELOCITY IN BURNER
LINES TO EUMINATE PRECIPITATION OF THE
PULVERIZED FUEL. APROX. 15% OF THE
COMBUSTION AIR ADDED AT THIS POINT.
-VARIABLE SPEED PRIMARY AIR FAN
Fig. 9.-Cross section of air swept tube mill with its auxiliary equipment as they
are commonly grouped.

A CROSS-SECTION TAKEN
THROUGH THE CENTER OF
THE BARREL OF THE MILL
AND ILLUSTRATES THE ACTIO'
OF THE CASCADING BALLS
WHEN PULVERIZING COAL
OR OTHER MATERIALS.
Fig. 10.-Cross section through center of barrel of the mill shown in fig. 9
Pulverized Coal Systems
601
Combined Impact and Attrition Pulverizer
In this mill, impact is accomplished by forged steel balls.
The mill is called a tube mill and combines the principle of
impact and attrition.
Describe the construction of the mill.
Ans. Fig. 8 shows details of construction. It is built in various
diameters from 24 inches to 96 inches and in lengths desired
for producing a given tonnage. The heads of these mills have
trunnions cast integral. A steel shell with angle flanges at either
end is bolted to the heads and corrugated liners are keyed to
the inside. A cut herringbone gear is mounted on one of the
angle flanges.
Figs. 9 and 10 show further details.
Describe its operation.
Ans. The barrel of the mill is charged with forged steel balls.
The balls are charged into the mill through the feed end while
the mill is in operation. The counter shaft is direct connected
through a flexible coupling to a motor, or it may be driven by
belt, silent chain drive, or direct connected to a steam engine.
Material is fed into the mill in desired quantities by a disc feeder
preferably driven by a 14 horse power variable speed motor. A sleeve
from the discharge end of the tube mill leads into the fan housing. The
mill is rotated at a speed which causes the balls to be carried around by
centrifugal force to a point where they are thrown down on to the
material to be ground, just as you would throw a ball on a piece of
material to be crushed. The result is a continuous cascade of balls
delivering thousands of blows per second.
How is the pulverized coal discharged?
Ans. The air swept tube mill has no mechanical discharge
and depends upon the air passing through the mill to float out

602
Pulverized Coal Systems
the carbureted product. An adjustable opening in the feed end
housing admits, preferably, pre-heated air in desired quantities.
A fan connected to the discharge end trunnion and driven by
a variable speed motor draws air through the mill, removing
only the impalpable powder through the discharge end of the
mill, thus controlling the velocity of the air through the mill
and thereby the fineness of the product.
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Fig. 11.-Vortex burner. In operation, the primary air and coal are delivered
through a flat orifice, usually horizontal. Coal and primary air impinge on a
V-shaped tip, or deflector, placed in front of the burner. This deflector is
adjustable to and from the orifice of the burner. By the impingement of the
fuel on the deflector, the stream is divided into two parts, one upward and one
downward. Secondary air is delivered to the wind box and passes over the
curved deflectors shown above and below the burner tip. This secondary air
is delivered at a pressure which drives it into the fuel stream, the result being
intense turbulence at the burner tip and a short flame with highly efficient
combustion.
Note.-Fineness and inflamability.-Messrs Bouton and Haynor of the United
States Bureau of Mines and the Carnegie Institute of Technology carried on an
investigation to determine the flamability, or rate of flame propagation, with coal
dust of various fineness. The conclusions reached after a series of tests are that
the flamability of coal dust increases with the fineness and that the maximum
flamability is reached with coal dust within the range of from 10 to 25 microns in
diameter (one micron equals one millionth part of a meter). The flamability of
dust of larger sizes decreases through the range up to the size of 25 to 74 microns
diameter, at which point the flamability has decreased to a very marked extent.

Pulverized Coal Systems
603
How is additional air obtained?
Ans. It is admitted between the discharge end of the mill
and the fan housing, from which the coal is delivered directly
to the burners set in the furnace wall.
Burners
In pulverized coal firing, turbulence through the furnace is
essential:
Fig. 12.-Rotary burner. This burner, which is suitable for coal, gas or oil, is
particularly adapted and recommended for Scotch marine boilers and boilers
of the return tubular type. In operation, the primary air and coal are delivered
at a tangent and pass through an annular orifice over the Vortex tip, leaving
the orifice with a rotary action of relatively high velocity. The secondary_air
is also delivered in a rotary manner, on the outside of the coal stream. The
combination of the Vortex deflector and the rotary action results in probably
the most intense form of turbulence it is possible to produce under the given
condition. This intense turbulence results in proper mixing of the fuel and a
short, highly radiant flame.

604
Pulverized Coal Systems
Fig. 13.-Type R burner for firing pulverized coal and oil. This burner for horizontal firing provides for
uniform distribution of the coal and air within the nozzle by means of deflectors and vanes.
Fig. 14.-Assembled view of type R burner.
dod of
80/

Pulverized Coal Systems
605
1. To bring oxygen and combustible into continuous contact.
2. To scrub away the ash from the surfaces of the particles,
and
Notator HO0
3. To cause the gases to sweep the water heating surface in
the furnace.
Without intensive mixing of coal and air, efficient combustion is
impossible. Scrubbing of the coal particles assures contact between the
combustible and oxygen, thus promoting rapid combustion and re-
ducing carbon loss. Sweeping of the water heating surface in the
furnace by the gases increases the evaporation rate for the furnace
heating surface.
0x0
How is turbulence obtained?
51
Fig. 15.-Type R burner for firing oil and gas. This burner has interchangeable
parts and may be converted to burn pulverized coal.

606
Pulverized Coal Systems
Ans. This may be obtained either by variations in design
or arrangement of burners. The most effective method is an
arrangement of simple nozzles which provide turbulence by
impingement of one flame upon another.
Corner (or tangential) firing is an example of this principle. It is
generally conceded that where it can be applied, this type is the most
preferable for thorough mixing of coal and air. These burners have
horizontally adjustable nozzles arranged in a casing with forced draught
air ports.
The construction is indicated in figs. 11 and 12. Details of type R
burners are shown in figs. 13 to 15. Other designs are shown in figs.
16 to 19.
21.017
Fig. 16.-Plan of tangential burner showing adjustable nozzle.combat

Pulverized Coal Systems
607
Bulls me
babi
Automatic Control
Response to demands for changes in the rate of coal supply
from the mill to burners is obtained by simultaneous changes in
proper relation of the coal feed and air supply to the mill.
uulami
PAYD Dam
diuitulba 21
How is primary air flow controlled?
Ans. By adjusting the exhauster inlet damper.
How is the mill feed controlled?
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Fig. 17.-Arrangement of tangential burner for coal and oil in corner of furnace
showing operating mechanism for secondary dampers and adjustable nozzles.

608
Pulverized Coal Systems
Ans. By adjusting the speed of the feeder driving mechanism
or motor. If these two controls be attached to an automatic
system, they will respond to the changes in loading pressure
acting in the system.
Tintody ato
do at
To mi os
How should the controls be arranged?
KENNEDY
sam
Fig. 18.-Duplex burner, suitable for small installations. With this burner the
secondary air is furnished by natural draught. It will be seen from the illus-
tration that the stream of primary air and pulverized coal is divided into two
parts through an upper and lower channel. These two streams impinge on
each other as they leave the burner and result in intense turbulence giving
efficient combustion.
Ans. The controllers on the mill feed and primary air should
be arranged to permit separate, remote manual control of each,
and also be readily transferable from manual to automatic,
and vice versa.
What precautions should be taken?
Ans. For the most satisfactory mill performance, the

Pulverized Coal Systems
609
Fig. 19.-Rotary burner, designed for either natural or forced draught. The bur-
ner elbow can be bolted to the air housing and burner nozzle at any angle
suitable for the particular pipe layout. The elbow carries an attachment for
holding the coal diffuser rod and the necessary stuffing box arrangement for
making this assembly dust tight. The air housing for natural draught type
burners is a standard cast iron drum type air box with an adjustable air register
on its periphery to allow for the admission of the necessary amount of secondary
air for combustion, taken into the air box and furnace by the stack draught.
The adjustable air register is equipped with blades which give the secondary
air a rotary motion in the same direction as the rotation of the primary air
and coal passing through the nozzle and coal diffuser. When using secondary
air under pressure from a fan, the steel plate type air housing is used, and is
equipped with a damper to allow regulation of the proper amount of air to
be taken into each burner. All air housings are equipped with two peep holes
for observation purposes and for inserting the torch for igniting the coal or oil.
The burner nozzle is located centrally in the air housing and discharges the
coal delivered to it from the burner elbow into the furnace. In the inside of the
burner nozzle the coal diffuser is inserted consisting of a series of curved radial
blades which give the stream of primary air and coal a spiral motion. The
position of the coal mixer in reference to the burner nozzle, is not fixed and
should be adjusted by pulling the supporting rod in or out. This adjustment
will affect the length and the spreading of the flame. To keep the coal mixer
in a central position when outside the burner nozzle, a separate three leg
support is attached to the coal diffuser rod or pipe. This keeps the coal
diffuser or mixer concentric with the burner nozzle.
610
Pulverized Coal Systems
A Supply
Tempering
Air Damper
Motor
Loading Press.
T
A
•=101=:
Shut-off
Gate
=000=6}
Mill Motor
Power Circuit
Air Supply !
Current
Trans-
former
-
-Thermostat
Pulverizer
80
Feeder
Feeder
Motor
Current Relay
Normally Closed
Resets Automatically
Push
Button
Line
To
Burner
Exhauster
Recording
Temperature
Indicator
& Controller)
Range
0 to 500°F
Feeder Motor
Starter
Fig. 20.-Diagram of automatic control system for bowl mill.
Loading i
Press. 1
Exhauster
Inlet
Damper
+1
Air Supply Lines
Primary Air Press.
Suction at Mill Inlet
Ammeter
Control Panel
Transfer &
Remote
Manual
¡Control Valves
Loading
Press.
More - Less
Relay Valve's
Master
Regulator

Air
Supply

Pulverized Coal Systems
611
hellorto
98000
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Valen
Sh
Fig. 21. Typical shadow wall and pulverized fuel brine setting. The tubes are
set some distance from the refractory wall, and spaced in such a manner that
the refractory wall is under the cooling effect of the water tubes. At low
ratings approximately one-half of the tube surface absorbs radiant heat; that
is, that part of the tube facing the flame. If the rating be increased, the refractory
progressively becomes hotter and automatically reflects heat on to the back
of the water tubes. Thus the total tube surface is exposed to radiant heat or
reflected heat from the refractory wall.
612
Pulverized Coal Systems
temperature of the primary air and coal mixture should be held
at the recommended temperature for the output. Excess tem-
perature may result in pulverizer difficulties. Temperatures
which are too low do not produce sufficient drying during
pulverization and interfere with normal operation.
The use in the mill exit of a recording thermometer 'with regulator
connected to the hot air inlet damper is recommended. Where auto-
matic control of temperature is desired, a recording temperature con-
troller may be connected to the receiving regulator.
Describe the hot air control.
Ans. Atmospheric air for tempering the hot air is controlled
by a balanced damper in the atmospheric inlet, which is opened
by a difference in pressure on the inside and outside of the mill.
How is over loading of the mill prevented?
Ans. A current transformer should be installed in one phase
of the feeder motor circuit, with the secondary coil connected
to a relay which is normally closed. The contacts of the relay,
which should be adjusted to trip at normal full load current
and to reset at 20 per cent under normal full load, are con-
nected in series with the feeder motor.
Automatic control as just described is shown in the diagram fig. 20.
-
Oil Burners
613
CHAPTER 35
Oil Burners
Fuel Oils
What should you know about fuel oils?
Ans. Some knowledge of fuel oils is essential for the intelligent
operation of oil burners. Fuels are derived from crude oils from
different fields and vary considerably.
How are fuel oils classed?
Ans. Domestic fuel oils are classed as Nos. 1, 2 and 3;
industrial fuel oils as Nos. 4, 5 and 6.
Give another classification.
Ans. Sometimes the fuels are referred to as light, medium
and heavy domestic oils; and light, medium and heavy in-
dustrial oils.
What determines the grade of oil that can be used?
Ans. The particular grade of fuel that can be used is usually
fixed by the design of the burner with respect to the method
of spraying, the type of ignition, etc.
614
Oil Burners
I
H
K

HO
с
E2
ES E3-
E¹
B
E4
B2
Figs. 1 and 2.—Non-mixing gravity feed vaporizing or gas type burner and
automatic control. It is designed for gasoline or other light hydrocarbons or
ordinary headlight oil, of 150° test. In operation, the oil is supplied through
a pipe to the vaporizer indicated by the letter A, In its passage through the
fire box and the vaporizer, it is converted into a vapor or gas which burns
without odor, soot or residuum. From the top of the vaporizer A, the gas is
conveyed through an elbow pipe C, as shown by arrows, to the mouth of the
burner, where it escapes through a small opening D (made adjustable), and
is ignited. The flame striking centrally upon the bottom of the vaporizer A, is
spread in every direction, thus serving the double purpose of generating the
gas in the vaporizer and distributing the heat equally to every portion of the
boiler. The flame striking centrally upon the bottom of the vaporizer is spread
radially and by heating the vaporizer converts the liquid fuel into gas. Working
in this small opening D, is a shut off plunger E, which, raised or lowered,
controls the flow of the gas. This plunger is connected by means of a rod E¹,
counter-balanced rock shaft E2, bell crank lever E3,connecting rod E5, to bell
crank lever H, and to a hallow spring on the outside of the furnace. The
weight of these rods is counterbalanced by the rod and ball E4. The hollow
spring is supplied with steam at boiler pressure through a small pipe at opening
K. The saucer F, is for oil or alcohol used in raising the proper heat under
vaporizer at starting, and until sufficient gas is generated for its own reproduc-
tion; a matter of three or four minutes. The burner is furnished with removable
Oil Burners
615
For instance gravity feed burners invariably are designed to burn
only the high grade distillates, the domestic burners use oil as heavy
as No. 4.
Upon what does the cost of heating to a considerable
extent depend?
Ans. The grade of oil which can be burned.
General Principles of Oil Burning. To ignite properly,
oil spray must be mixed with air so that it will vaporize and
gasify. The higher the temperature and the Baume of the oil
at the burner, the easier it is to spray and the air pressure may
be correspondingly lower. The temperature at which it begins
to vaporize is the limit to which any oil may be heated.
The lower the pressure at which the oil and air can be used, the less
will be the cost for power; furthermore, a minimum of difficulty will
be encountered from foreign matter clogging valves, as the throttle
opening will be correspondingly larger and thus permit most of the
dirt to pass through.
The air and oil pressure at the burner should be steady.
The air blower should be of sufficient capacity, and pipe lines large
enough to deliver the volume of air without more than 10% drop in
pressure.
Figs. 1 and 2.-Text continued.
plugs BB1 and B2 for cleaning. Rock shaft E2 is furnished with stuffing box G,
to prevent leakage. In control, the straightening of the spring caused by an
increase of pressure in the boiler, operates directly on the plunger by means
of the adjusting screw I, bell crank lever H, and intermediate connections;
thus establishing the relation between steam pressure and fire. Should the
steam pressure rise, the plunger would close off the flow of gas correspondingly,
and vice versa, thereby regulating the heat of the fire. The plunger cannot,
however, shut off the flow of gas entirely; a small orifice is always left, enough
to keep the burner and boiler hot; and in this way the trouble and annoyance
of having to relight the fire after every stop is avoided.
616
Oil Burners
All of the oil should be gasified before the flame impinges on any
obstruction, refractory or otherwise. If it be not thoroughly gasified,
the impingement will cause a carbon deposit or the rapid destruction
of the refractories; the end of a long, lazy flame, however, is not espe-
cially destructive to refractories.
The speed of emission for some gasified oil and air must be
less than the speed of propagation of the flame or it will not
ignite.

GRAVITY FEED-
CONTROL VALVE
TANK
VAPORIZER
GAS
BOILING
OIL
AIR
AIR
AIR
Fig. 3.-Elementary gravity feed induction mixing vaporizing burner. In
operation, oil flows from tank to vaporizer, regulated by the control valve.
The flame from the burner vaporizes the oil entering the vaporizer producing
a gas which passes out to the mixer. The gas is injected through a nozzle into
the mixer drawing in air, the mixture passing out and igniting at the top.
For the most efficient combustion, all of the air entering the
furnace should pass through the oil spray so that all of the
air will be used, and the oil be consumed with the least excess
of air.
The length of the flame depends on the fineness of nebulization the
size of the droplet of oil. It also depends on the temperature of the
droplet, temperature of the surrounding air and the ability of the
droplet to absorb the necessary volume of air for complete combustion.
Oil Burners
617
Oil Burners
(Classification)
What is an oil burner?
GAS
VAPORIZER
Ans. By definition: Any device where-
in oil fuel is vaporized or so called
atomized* and mixed with air in
proper proportion for combustion.

BOILING
OIL
OIL
NOZZLE
FAN BLOWER
AIR
NOZZLE
OIL
AIR
AIR MIXING WITH GAS
MOTOR
Fig. 4. —Elementary gravity feed mixing, vaporizing burner. Connected to the
burner is a fan blower with outlet pipe surrounding the gas pipe as shown.
In operation, air from the fan blower mixes inside the burner with the gas
coming from the vaporizer. Thus the air is mixed with the gas before ignition,
resulting in a blue flame and efficient combustion.
AIR
AIR

LEVEL.
AIR
VALVE
TO
AIR
SUPPLY
Ol
ΤΟ
OIL SUPPLY
Fig. 5.-Sprayer burner. The oil is brought through an orifice directly across the
path of the jet of air or steam and is "brushed" off by the latter and sprayed.
*NOTE No oil burner splits up the fuel into atoms, that is ridiculous, it
simply sprays the fuel in a fog-like mist - good advertising talk:
618
Oil Burners
How are oil burners classed?
Ans. In numerous ways as to methods of: 1, Operation;
2, ignition; 3, gasifying; 4, oil feed, etc.
More in detail they may be classed as:
1. With respect to the gasifying process, as:
a. Vaporizers.
b. Sprayers.

A B D EN
STEAM
OIL
Fig. 6.-Projector burner. The oil is pumped to the oil orifice and caught by the
air or steam jets which are located some distance back of the oil orifices.
2. With respect to the atomizing agent, as:
a. Air;
b. Steam.
a. Outside mixing
3. With respect to the method of spraying, as:
drooling;
atomizer;
b. Inside mixing
STEAM
projector;
(centrifugal;
chamber;
injector;
centrifugal.
Other types are: Rotary, high pressure, low pressure gun type, pot
type, etc.
Oil Burners
619

ليا
Fig. 7—Outside centrifugal burner.
E
B
| | | | | | | | | | |
|
| | |
D
||||
//
....

Fig. 8.—Inside centrifugal burner. In construction, at the end of the pipe A,
that conveys the oil, the oil passage B, is tapered down to the opening C,
through which the oil is discharged. The series of slanting vanes D, on the rod
E, deflect the oil and break it up into a number of currents, each of which has
a whirling motion as it enters the space F, around the end G, of the rod. The
centrifugal force due to the whirling motion given by the vanes causes the
spray to spread on leaving the burner as shown by the diverging lines.
620
Oil Burners
What is a vaporizing burner?
Ans. One in which the fuel oil is vaporized by heating in a
retort.
What do you understand by the term vaporize?

7
OIL THROWN OFF
BY
CENTRIFUGAL
FORCE
MOTOR
DRIVE
STUFFING BOX
OIL DUCT
REVOLVING
DISC
OIL PIPE
Fig. 9.-Elementary centrifugal force atomizing burner. The oil flows through the
hollow spindle of a disc which is rotated at high speed by a motor. The oil
overflowing at H, onto the disc at its center is hurled off the disc by centrifugal
force, and ignited by a torch or pilot light, produces a ring of flame.
Ans. A fuel is vaporized when a change of state takes place,
that is, a transformation of the fuel from the liquid to the
gaseous state.
Careful distinction should be made between vaporizing and alleged
atomizing burners later explained.
#
Oil Burners
621
Name two types of vaporizing burner.
Ans. Mixing and non-mixing.
How does a vaporizing burner work?
Ans. The fuel passes from the source to the retort or vaporizer
which is a closed vessel heated by the burner underneath,
Fig. 10.-Injector inside mixing burner.
OIL AND STEAM
OIL

OIL.
STEAM

E60310
STEAM
Fig. 11.-Chamber burner. The oil and steam are more or less mixed before
issuing from the burner. With this burner the oil is heated before leaving the
burner.
causing the oil to boil and supply gas to the burner. In the
non-mixing type mixing takes place when the gas leaves the
nozzle of the burner. In the mixing type the gas from the
vaporizer passes into the mixer into which the gas is injected
bringing with it the air, the resulting mixture passes out
through small holes where ignition takes place.
622
Oil Burners
A familiar example of this kind of mixer is the ordinary cook stove
gas burner.

OIL VAPOR
FLAME
LIQUID OIL
•
Fig. 12.-Hot plate method of vaporizing oil.
TXH HAV
ミ
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#
MI T
11/
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lin
-FLAME
IMPELLER
PLATE
۱۱۱
"1\
HOT PLATE

INSPECTION
DOOR
PEEP
HOLE
BURNER
AIR DOOR
EXTENSION
Fig. 13.-Mechanical burner as applied to a Scotch marine boiler.

Oil Burners
623
Ans. It is limited to high test or relatively high cost fuels
because the external mixing by natural draught is not very
efficient unless a highly volatile fuel be used.
What is an atomizing burner?
Ans. A misnomer.
X-2
X-1
X-5
X3 X4 X6 X-12
X-11
TO
X-13 X9
X-10
X-7
X-8
Fig. 14.-"Twinplex" mechanical pressure sprayer (atomizing) burner. Wide
range type. Burner parts: X1, Tip; X2, nut; X3, body; X4, min. atoms
X5, max. atom.; X6, inner tube; X7, handle; X8, union bushing; X9, housing;
X10, housing screw; X11, jacket tube; X12, outer tube; X13, housing body.
0
Figs. 15 to 18.-"Twinplex" mechanical pressure burner nut, tip and sprayers
(atomizers).
624
Oil Burners
FURNACE FRONT PLATE
1/2" SHEET ASBESTOS

36
11 25
☆
29
84 82 12
Fig. 19.-"Twinplex" mechanical pressure sprayer (atomizer) burner and natural
draught register. The parts are: 11, flame cone; 12, flame cone rod and nut;
25, jacket tube set screw; 29, lighting door; 36, clamping bolt; 82, gear shaft;
84, quadrant gear. The natural draught register is designed to give a large range
of capacity with a positive and wide variation between the maximum and
minimum air admission. Air adjustment is accomplished by regulating the
small and large ring plates on the air register by means of the handle provided
for that purpose. Adjustable stops are also provided so that the best setting
can be maintained at all times. The entire air register is hinged, permitting
access to the furnace and all parts of the air register and burner. In common
with all mechanical pressure atomizing burner air registers, all the air for
combustion is admitted at the burner.
Oil Burners
625

1
2
BY PASS AIR
OIL PASSAGE
MAIN AIR LINE
Amma
5
6
4
3
Fig. 20.-Multiple spray oil burner for low pressure air. The parts are: 1,
spindle; 2, sleeve; 3, spindle cap; 4, body; 5, body cap; 6, sleeve cap;
7, spreader. In operation, the oil is picked up and forced outward from the
point of the oil spreader by a stream of air; then it meets a second stream of
air just as it reaches the head of the spreader; a thin film of oil is thus forced
outward in the form of a cone of very fine spray. The burner is provided with
a cone shaped spreader which is heated by reflected heat from the furnace and
receives the oil at the point of the cone. The oil is blown along the cone by
air. It is expanded and thinned as it travels along the cone and leaves the
cone in a finely nebulized state. As the oil issues from the oil passage, the
by pass air picks it up and forces it outward on all sides from the point of the
spreader (No. 7 in diagram) it meets the second jet of by pass air which is
directed at an angle to strike the spreader. The thin film of oil is thus forced
outward in the form of a cone of very fine spray; the fineness depending on
the air pressure, the viscosity of the oil, and the size of the base of the spreader.
Operates on air pressure as low as 8 ounces with light oil. Only a small portion
of the air passing through the burner (that part going through the by pass) is
used for spraying. Less than 1% of the air goes through the by pass to form the
spray, and it is always at full air pressure. The greater volume of the air passes
through the body cap to support combustion and can be varied from off to full
air pressure. The combustion air having passed through the body cap, strikes
the spray one or more times, depending upon the type of burner, to change its
direction and lower its velocity, thus obviating the necessity for a baffle wall'
or block.

626
Oil Burners
Why?
Ans. It gives the impression that the burner actually breaks
up the fuel into atoms; although very good hot air sales talk,
it is very far from the truth.
What does an alleged atomizing burner really do?
920
lo movi
bazio
buo an
ydonos
eit
log
54T
39
uchos lom
Fig. 21. Multiple spray fuel oil burner in upright working position. Instruc-
tions for installation and operation: On a cold furnace, it may be
necessary at times to start the burner partly throttled until the vents begin to
function properly. The spread of the flame can be varied. Screwing the cap
further on will widen the spray and shorten the flame. Unscrewing the cap
will squeeze the flame and lengthen it. If a very short, high temperature flame
be desired, it is sometimes necessary to enlarge the taper of the burner hole
inside the furnace. It is often good practice to place an oil shut off valve back
Oil Burners
627
Ans. It breaks up the liquid fuel into very minute liquid
particles, that is, it separates a jet of liquid into a finely divided
spray, resembling "liquid dust.”
The term "atomizer” is a misleading term and should not be used.
What should a so called atomizing burner be called?
Ans. A sprayer.
How does a sprayer work?
Ans. Air or steam blown through a nozzle draws in oil which
mixes with the steam or air and passes through the nozzle tip
as a spray of steam or air mixed with very finely divided
particles of the fuel.
Name two types of rotary burners.
Ans. 1, Vertical; 2, horizontal.
How does a rotary burner work?
Ans. The basic principle of operation is centrifugal force, that
is, the oil entering at the center of a rotary cup is whirled
around very rapidly until the oil is thrown away from the
cup. Being mixed with air, it will ignite.
Fig. 21.-Text continued.
of the oil control valve. The oil control valve can then be adjusted and set for
perfect combustion and the shut off valve used to turn the oil on and off. If the
flame blow away from the tunnel-way of the block when the burner is operating
at the required maximum, the tunnel-way is too small and should be enlarged
on the inside of the black or wall. The burner will operate on cold air at any
pressure above 12 ounces, and on any oil pressure above 5 lbs. at the burner.
Never place an air control valve back of the burner, as full pressure is needed
through the by pass unless pressure is above 2 lbs. For cleaning, the burner can
be entirely dis-assembled without disturbing the pipe connections, except the
union shown at the left of the oil control valve. By unscrewing the large hexagon
at the back of the body, all the internal parts of the burner can be readily
removed. The oil passage in the burner can be cleaned by removing the 8 in.
pipe plug at the back of the oil control valve; the passage is a straight line
through the burner.
628
Oil Burners

B
D
G
H
Be
A2
A₂
3
B,
B,
Az
H-
A,
10-5--F
F
--B
A
Fig. 22.-Typical installation of a multiple spray fuel oil burner in position and
piped for using pre-heated air and automatic temperature control. A, uncon-
trolled cold air from the main air line to the by pass opening on the burner
head, the by pass piping around the butterfly air valve on the burner having
been disconnected. This by pass air A, is 15 per cent of the total air which
passes through the burner, and is sufficient for the low burning position when
automatic control is used. This small current of cold air also serves as a blanket
protector for the oil tube and spraying parts of the burner from the hot air
when a recuperator is used. This protection prevents premature vaporization of
the oil at these points, and also the possibility of oil being left in the burner
to carbonize and block the channels. A1, controlled air from the motor
operated air and oil valve C; A3, recuperator or heat exchanger which heats
the air for combustion on its way to the burner, by means of heat from the
waste gases from the furnace; A2, controlled hot air line to the main air
opening on the burner; B, oil line from the source of supply to the automatic
oil control valve and by pass at C; B1, oil supply pipe to the oil control valve
F, on the multiple spray burner. All branch lines should be as nearly as
possible of equal length; D, butterfly air control valve, built into the burner;
E, the burner proper, which sprays the fuel oil and mixes oil and air; G,
induced air control. When pre-heated air is used this control is used for
lighting only, being closed tightly at all other times. G is machined to fit
the body cap of the burner. H, bracket bolted to furnace holds burner in
position.

Oil Burners
629
What do you understand by vertical and horizontal
rotary burners?
Ans. Vertical and horizontal refer to the position of the
shaft, not the cup.
What is the application of the vertical type?
Ans. It is used as a domestic burner, installed in the boiler
with all controls located adjacent to the burner.
OIL PRESSURE
REGULATOR
OIL SHUT-OFF
VALVE
OIL
FILTER
AIR SHUT-OFF
VALVE
OIL PRESSURE
GAUGE
OIL
MICRO REGULATING
VALVE
AUTOMATIC
CONTROL LEVER
CONNECTION
航
​BURNER
MOUNTING
BRACKET
BURNER
PROTECTING
SHUTTER
AIR CONTROL
SLEEVE
Fig. 23.-Proportioning oil burner low pressure type. The moving of a single
lever automatically controls the oil and air supply and simultaneously adjusts
both primary and secondary air orifices in the burner. Any desired oil-air
ratio once set is automatically maintained thereafter. In operation, it main-
tains the desired furnace atmosphere, consistently giving CO, readings between
13 and 15 per cent over the full range of the burner rating. Combines a straight
line flow oil control valve with a straight line flow air control mechanism in a
single, compact, rugged unit. It is adapted to industrial heating operations
requiring furnaces, boilers, dryers, ovens, kilns, lehrs, retorts, roasters, stills and
pre-heaters in the metal, smelting and refining, metallurgical, metal working
and finishing, foundry, enameling, ceramic, glass making, cement, chemical,
food and kindred industries.
630
Oil Burners
·
2 3
S
7 8
10

|| 12
13
14 15 16
OOC
o
acet: 1
質量
​Մ
Fig. 24.-Sectional view of the proportioning oil burner shown in fig. 23. In
construction, the oil control valve 3, consisting of a V groove in a flat
surface, covered by a rotating cam 2, is bolted to the burner back plate 5.
Screwed into the bottom of the oil valve is the oil tube 9 on the opposite end
of which is the oil nozzle 10. Around the oil tube and supported by the burner
back plate is the inner air nozzle operating tube 8 and the inner air nozzle 12.
The operating lever 4, causes the inner air nozzle to move backward and
forward and at the same time rotates oil control valve cam 2. To explain
the operation of the burner, moving the operating lever 4, clockwise
causes the inner nozzle operating pin 7, which is screwed into the inner nozzle
operating tube 8, to move in the curved slot 6, in the back plate tubular
section and thus move the inner air nozzle 12, of the burner back from the
outer air nozzle 11. As the inner nozzle moves back, the discharge areas at
16, between the inner and outer air nozzle, and at 14, between the inner air
nozzle and the oil nozzle are simultaneously increased, thus permitting more
air to flow out of the burner. Also connected to the operating lever 4, is the
oil control valve lever 1, so that as the operating lever is moved forward or
backward, the oil valve cam is also rotated and more or less oil is allowed to
pass through the V groove into the oil tube and nozzle. The primary atomizing
air passes through tangential primary air supply openings 13, in the inner air
nozzle, which gives it a rotary motion as it enters the space around the oil
nozzle. It then leaves the burner through the primary air discharge area 14,
picking up the oil from the holes in the oil nozzle 15, as it leaves. This high
velocity rotating primary air thoroughly breaks up and atomizes the oil. As the

Oil Burners
631
9 ouni
5811
AUCY
CROOKLYS
ei woll
an A
diddo
1ted W
f
an A
Fig. 25.-Venturi low pressure oil burner. Adaptation is for installations where
flexibility of heat is required and where steam or compressed air is not avail-
able, or if available, is too expensive to use for atomizing purposes. In
operation, the air enters the inner or venturi tube through four tangential slots.
These slots give a rotary motion to the air which strikes the oil, issuing at an
angle from the multi-ports of the oil injector in a venturi throat where the
rotating air is at its maximum velocity. This rotating body of air blasts and
breaks up the oil into a finely divided fog like mixture of oil and air which
leaves through the constricted center orifice at the burner nose.OR
RIA
on
Fig. 24.-Text continned.
primary atomizing air and oil mixture leaves the inner air nozzle of the burner
in a diverging cone, the mixture is met by the secondary air from the secondary
air discharge opening 16, leaving the burner in a converging cone, thus further
atomizing and mixing the oil and air to produce a fog of oil and air which is
quickly ignited and easily burned. This thorough atomization with proper ratios
of oil and air, which are secured by oil pressure and the oil valve setting on the
burner, are maintained over the complete range of the burner. Once set, all
that is necessary to change the heat input is to move the operating lever 4,
of the burner.

632
Oil Burners
How is the horizontal rotary burner installed?
Ans. On the outside of the boiler, the cup extending into the
chamber.
What is a pot type burner?
Ans. A hot plate burner.
FOG LIKE
AIR
AND
OIE
MIXTURE
AIR
or
STEAM
Fig. 26.-Venturi high pressure oil burner (phantom view). Designed for air or
steam at 30 lbs. per sq. in. gauge pressure and higher, and for oil from 5°
Baume up; the heavier grades require pre-heating.
OIL PORT
OIL
AIR
COR
STEAM
Fig. 27.-Detail of venturi high pressure oil burner as shown in fig. 26. The
illustration shows a venturi port where air or steam meets the oil at its greatest
velocity.

Oil Burners
633
How does it work?
tol of boniopor
Ans. Fuel oil drops into a hot plate (kept hot by constant
heat either gas or fuel oil permitted to flow slowly into the
chamber). The hot plate vaporizes the oil.
ibnos
What are the essential parts of the gun type burner?
Ans. This sprayer, perhaps called gun type on account of
its shape and the high pressure required (100 lbs.) for its opera-
Eje
Figs. 28 to 30.-Venturi "flat flame" high pressure oil burner. Adaptation,
steam or compressed air at 40 lbs. per sq. in. and higher. It will burn oils of
19° Baume and lighter without heating, and all heavier oils, if preheated.
Because of its flat flame design, it is particularly well suited to firing boilers,
and large heating furnaces where a soft spreading flame is desired. All the
venturi ports are on a horizontal plane, and placed to give a flame spread of
either 30° or 45° as specified. The illustration shows oil burner with piping
and valves to the left of burner. Another pattern has piping and valves to the
right of the burner. The burner parts show how the venturi ports are placed to
give a flame spread of 45°.inprotte o ravip illo to moo0/M.FE.pil
woll lia la temel amor ertion los millo
tion, consists of three essential parts: 1, strainer; 2, pump; and
3, pressure regulating valve. b bogolque ai diral &
7079
inu (su) a lo beni beau si vlny sweet
How does it work?
Ans. The pump forces the oil to the regulating valve at 100
lbs. pressure, this pressure being maintained by the regulating

634
Oil Burners
valve. This pressure is required to force the fuel through the
small orifice in the nozzle tip. Surplus oil is by passed back
either to the strainer or to the tank, depending upon operating
conditions.
If an oxi je bil on T: Comm
What are the three methods of by pass? om sud
Ans. 1, Two pipe system; 2, internal; and 3, an external loop
of copper tubing from the by pass to the strainer as used wher
6
8
10
PATENTS
0
12
BATCK
HAUCK
16
14
PENDING
50 +2
S
MFG.CO
BROOKLYN, NY.
@
Fig. 31.-Micro cam oil valve. It gives a straight line discharge. Each calibration
In the dial has the same increment of oil flow.
::
a gravity tank is employed and separate pump, strainer and
pressure valve is used instead of a fuel unit.
for sub woll
How is the internal by pass constructed as found on all
three part units (pump, strainer and valve)?

Oil Burners
635
Ans. The construction is such that the unit may be adapted
to operate with either lift or gravity feed. w but snob ei
ban bono al with lote ya Tan
How is the internal by pass changed to external by pass?
Ans. By means of the 1/8 inch plug which must be left in
position to close the internal by pass.
moilsoul guiq Inori od funds beton ad bloc
len191?
oral sill
puhelugen om
wolf
Por
viab bal
kums koo7O
CLOSED
3
HALF OPEN
Fin
QUARTER OPEN
Jor W
To noi Du 20 ei ind
Soyley
FULL OPEN
home heal
at woll
790 enk
hot at woll
art Z
singale nis zd
Tayith fotorada 659219 161 77
4
adTanA
Figs. 32 to 35.-Micro control from full opening to full shut off. 1, closed;
2, quarter open; 3, half open; 4, full open. A turn of the handle from absolute
shut off to wide open with evenly graduated capacity in between. The flow of
oil is governed by a cam with a knife edge rotating against a V slot in a
flat plane and working with very little bearing pressure. Follow the cam
movement over the triangular slot in the flat face and note that any desired
oil flow from minimum to maximum capacity of the valve can be secured. The
cam is ground to produce a straight line discharge curve. With this straight line
archaracteristic, the flow is directly proportional to the area of the slot opening
and to the number on the calibrated dial. Thus the pointer at No. 6 position
always indicates a flow three times the flow at No. 2 position. Q

636
Oil Burners
1
L
If internal action be desired (as with gravity feed) what
is done and what is it called?
Ans. The small plug is omitted and the outside by pass plug
is inserted so that no external line is needed back to the tank!
This is termed a one pipe job.
What should be noted about the internal plug location?
Ans. Location differs with different burners and must be
placed according to the instructions accompanying the burner.
How is the plug removed on a one pipe job?
Ans. With a long Allen wrench.
What is the construction of the pressure regulating
valve?
Ans. Several types are used as piston, diaphragm or bellows.
How is forced draught provided?
Ans. By means of a fan operating in an air tube and driven
by an electric motor.
What else does the motor drive?
Ans. The oil pump.
How is the fuel mixture issuing from the nozzle ignited?
Ans. Usually electrically by jump sparks.
What are the essential parts of the ignition system?
Ans. Two electrodes (spark points) spaced for a 6 in. air
gap and a transformer wound to step up the 110 volt line
current to about 10,000 to 15,000 volts.

Oil Burners
637
Operating Instructions
(Relating to the variable capacity pressure sprayer burner of fig. 36
and accompanying illustrations)
The sprayer must be inserted and securely clamped in the
quick detachable union connections. Open the oil control valve
00000
00
Fig. 36.-Half section of variable capacity pressure sprayer burner. The parts
are: 2, sprayer nut; 3, orifice plate; 4, sprayer plate; 5, nozzle body; 6, supply
tube; 7, sprayer barrel; 12, handle; 13, ferrule; 14, plug; G-1, gasket;
G-2, packing.
big ylabapo
isybige
gea noilo go bao noiby
builand Ji6 36
on the burner return manifold and be sure the return line beyond
this control valve is wide open.
povicl
DD
wako
adt
bitamib emped
The burner is now ready to light off. Insert the torch through the
opening in the closure plate. Open air doors and place the torch flame as
close to the diffuser as possible. Open the inlet valve. Slowly close down
on the return line valve until the spray ignites. It may be necessary to
quickly close and open the register doors to bring the flame up to the
sprayer. Remove the torch after the flame has been properly established.
Closing in on the return valve increases the oil flow through the sprayer,

638
Oil Burners
producing a larger fire. Adjust the fire to the desired size by means of
this valve. The supply pressure to the burners should be held constant.
Other fires as required, should be lighted off in the same manner and all
flames brought to the same size.
ORIFICE
PLATE
O
OIL RETURN INLET
ORIFICE
Oil Leaves Orifice in form
of a Hollow Conical Spray
Each Particle Following a
Divergent Path
WHIRLING
CHAMBER
SPRAYER PLATE
TANGENTIAL
SLOTS
ATOMIZER NUT OIL RETURN
PASSAGE
anam
W
Note Thickness of Oil
Woll Here all the O
Posses Through This Orifice
Note Thinness of Oil Wall Here, Only
the Oil to be Burned Passes This Orifice,
Remainder is Returned to Tank or
Pump Suction as Indicated by Arrows
wwww.
hm
Hollow Core Due
to Action of
Whirling Oil
NOZZLE BODY
6
ATOMIZER BARREL
→
Path of Flow
Indicated
by Arrows
Oil Supply
Under Pressure
and or Proper
Temperature
Oil Return to
Tank or Pump
Suction
Fig. 37. Variable capacity pressure sprayer burner. Diagram showing flow
of oil. In construction and operation a space is provided between the
brorifices of the two plates 3 and 4 and as the oil enters these orifices, the pressure
parallel to the axis which is forcing the fluid outward has been converted into
velocity in the same direction due to the venturi effect of the whirling chamber
and its orifice. At the same time the rotating oil in the whirling chamber sets up
a definite centrigufal pressure perpendicular to the axis of the orifice. As the
rotating oil reaches the return annulus, the centrifugal pressure will force some
of the oil into this opening if the return line control valve be open to permit
its passage through the return line. The oil which is not thus returned continues
through the orifice in the orifice plate 3, with its energy undiminished, emerging
from this orifice in the form of a hollow conical shaped spray of minute par-
ticles of fuel.
1200

Oil Burners
639
It is usually best to put the burners on the main control valve
as soon as possible, so that all burners in operation may be
controlled from one station.
32
This is accomplished by slowly closing the main return control
valve until the size of the flame begins to increase, indicating that the
oil control is now on the main valve and not on the individual burner
return valves, which should be immediately opened wide so that they
do not interfere with the flame control. During these manipulations the
air to the burners is, of course, controlled so as to operate smokelessly.
FRONT VIEW
CROSS SECTION
REAR VIEW
Figs. 38 to 40.-Orifice plate of
variable capacity pressure sprayer
burner of fig. 36.
FRONT VIEW
FOL
CROSS SECTION
REAR VIEW
Figs. 41 to 43.-Sprayer plate of
variable capacity pressure sprayer
burner of fig. 36.
640
Oil Burners
As the pressure on the return line is an index of the quantity
of oil being fired for any given burner, the operators will quickly
learn to proportion this pressure with the amount of air required
to run smokelessly, and adjust the air to the oil flow as required.
If automatic combustion controls are being used, they should be
adjusted so as to provide the proper quantity of air to maintain a trace
of smoke. Most efficient results are obtained when operating in this
manner.
While a burner is in use, the oil control valve should never
be entirely closed.
A small amount of oil circulating through the sprayer is required to
prevent carbonizing and overheating at the sprayer.
On burners in use keep valves on supply and return lines wide open-
not partly open.
Maintain fuel oil pressure to burners at 300 pounds per square inch.
The temperature of the oil at the burner manifold should be that at
which the oil has a viscosity of 150 SSU, and should be carefully main-
tained with as little variation as possible.
Use enough air pressure for smokeless combustion, but only that
much.
Light off burners through lighting holes. Do not attempt to light off
from hot brickwork. Close registers for an instant after lighting off; then
quickly open again. This assists in properly igniting the oil.
Remember adjustment of sprayer jacket tube.
Check sprayer-diffuser distance occasionally.
Keep sprayer clean and free from grit, carbon or dirt.
To prevent overheating, do not place sprayer in idle register
until ready to light off and as soon as a burner is shut off remove
sprayer.
This will prevent caking of oil in the sprayer plate slots and the small
passages feeding oil to them.
This burner is so designed and constructed that the return pressure
has no effect on the spraying and regardless of the reading of the return
line pressure gauge this does not affect the quality of spraying.
Oil Burners
641
In shutting off burners the supply valves should be closed
first, followed by the return valve. The register may then be
closed.
The sprayer should be immediately removed from the register.
Care should be taken not to allow oil to drip on the front, piping, etc.
The burner should be allowed to cool before cleaning.
When cool the sprayer nut should be removed and the sprayer and
orifice plates cleaned. Extreme care should be taken so that the surfaces
of these parts and the nozzle body face are kept smooth and free from
dents, nicks or foreign matter.
DO NOT use steel or any other hard material in cleaning
these parts.
In storing orifice and sprayer plates do not place them in bags
or so that they will be shaken or thrown continuously against
one another. Store so that the finished faces are protected against
damage. It is important to keep them in good condition.
Port Operation.
1. For low rates of firing adjust flame size to suit rating re-
quired. Keep flame of sufficient volume to maintain combustion
close to diffuser.
2. If operating manually, maintain the boiler pressure by us-
ing the valve on the return line. Closing down on the valve in-
creases the back pressure on the return line and causes more oil
to be burned and opening the valve reduces the back pressure and
decreases the firing rate. Only a small movement of this valve
is necessary to make a substantial change in firing rate. Do not
forget to change the air supply when changing the oil rate.

642
Oil Burners
Con.00
9210
Porno
Ent
AIR DIFFUSER
JACKET TUBE
Note
Face of Atomizer Nut 1/2" in Front
of Point Where Diffuser Cone Begins to Flore
and
Fig. 44. Variable capacity pressure sprayer burner (of fig. 36) assembly.
RILE
Lo
CHECK VALVE AND DUPLEX
QUICK DETACHABLE UNIONS
la
besanto
pl

Oil Burners
643
3. If operating automatically for a lengthy period of time at
low rates of firing, it may be necessary to install a smaller size
of orifice and sprayer plate.
4. When blowing tubes in port it is advisable to shut off all
burners on the boiler being blown, raising the air pressure and
tou no lio
Jombon
E
Fig. 45. Variable capacity pressure sprayer burner (of fig. 53) shown complete
with air register jacket tube, diffuser assembly in center plate.
having registers wide open as the effect of the blowers may
extinguish the small fires usually used in port.
5. If for any reason the fires should become extinguished-as
can be seen from the lighting-off hole close all oil valves at
once. Do not try to light burners until the furnace is freed of oil
and vapor by allowing air to circulate through the boiler.
644
Oil Burners
6. The burners should be inspected and checked at frequent
intervals to detect dirty or partially plugged sprayers and flame
shapes should be observed. to see that they are uniform and of
proper contour.
7. Clean sprayers thoroughly each watch.
t
Operations While Under Weigh.
1. Use burners with sprayers of size and type as directed by
the engineer in charge.
2. Run with registers wide open.
3. Use only sufficient air to operate at trace smoke.
4. If operating manually, maintain the boiler pressure by
using the valve on the return line. Closing down on the valve in-
creases the back pressure on the return line and causes more oil
to be burned and opening the valve reduces the back pressure and
decreases the firing rate. Only a small movement of this valve
is necessary to make a substantial change in firing rate. Do not
forget to change the air supply when changing the oil rate.
5. If operating automatically, the controls should be set using
all register shutters wide open.
6. When blowing tubes, raise the air pressure by hand 1½ in.
to 2 in. higher than normal. Leave oil on automatic. Blow tubes.
7. If for any reason the fires should become extinguished—as
can be seen from the lighting-off hole-close all oil valves at
once. Do not try to light burners until the furnace is freed of oil
and vapor by allowing air to circulate through the boiler.
8. The burners should be inspected and checked at frequent
intervals to detect dirty or partially plugged sprayers and flame
shapes should be observed to see that they are uniform and of
proper contour.
Oil Burners
645
Domestic Oil Burner
Systems
Basic
The following presents the essentials of a simple forced
draught automatically controlled system.
What operating power is used for the system?
Ans. An electric motor.
What does the motor operate?
Ans. The fan for forced draught and the oil pump.
What duties are performed by the pump?
Ans. It pumps the oil from the fuel tank and delivers it to
the pressure regulating valve at the required pressure (usually
100 lbs.).
Describe the operation of the regulating valve.
Ans. 1, It regulates the oil pressure by by-passing excess oil
either to the tank or to the pump inlet line; 2, it opens the oil
line to the nozzle when the pressure has become high enough
for burner operation and closes the line when the burner shuts
down to avoid oil dripping into the combustion chamber.
How is the oil divided into spray?
Ans. By passing it through a nozzle under high pressure.
646
Oil Burners
How is ignition obtained?
Ans. When the room thermostat closes its circuit due to a
drop in room temperature, the ignition and motor circuits are
energized and the burner immediately starts operating.
How long does electric ignition continue?
Ans. Until normal combustion occurs, at which time rising
stack temperature will cause another device to operate and open
the ignition circuit.
Automatic Control
In order to understand the principles upon which the auto-
matic control equipment is based, the following is given, relating
to a very simple system which is basic of most of the systems
now in use. The system here presented is progressively built
up, illustrated with diagrams that anybody can understand.
How many circuits are required for a simple control
system?
Ans. Three.
What names may be given to them, based upon their
function.
Ans. Circuit No. 1-Power motor circuit; Circuit No. 2—
thermostatic time switch circuit; Circuit No. 3-primary con-
trol or stack switch, also called combustion safety control and
what not; stack switch circuit is the best name as it is self
defining.
Oil Burners
647
Describe the power motor circuit No. 1.
Ans. Current for operating the motor is taken from the house
power lines. One terminal of the motor is connected direct to
one of the power wires. In the other wire to motor is placed a
thermostat as in fig. 46.

110 VOLT SERVICE
LINE
MOTOR
CIRCUIT
1
THERMOSTAT
MOTOR
Fig. 46.—Automatic control power circuit No. 1. The motor circuit.
What happens when the temperature in the room where
the thermostat is located becomes too cold?
Ans. The thermostat closes the circuit which starts the
motor, which in turn operates the fan and fuel pump.
What is lacking in this one circuit hook up?
648
Oil Burners
Ans. No means is provided for igniting the fuel and no con
trol to act in case of faulty operation.
What is the next circuit to be connected?
Ans. No. 2 Circuit, that is the thermostatic time switch
circuit.

SERVICE
LINE
CIRCUIT
NO. 2
BREAK
THERMOSTAT
£
TIME SWITCH
CIRCUIT
2
TIME SWITCH
Fig. 47.—Automatic control power circuit No. 2. The time switch circuit.
Describe the hook up.
Ans. One line of the motor circuit is cut forming a break or
gap; across this gap Circuit No. 2 is connected. In this circuit
is the time switch, as in fig. 47.
Oil Burners
649
How does the time switch work?
Ans. It remains closed when no current is flowing, but does
not remain closed long when current is flowing. This is the time
element which is the basic idea of this switch.
G
STACK SWITCH
Describe the operation thus far when the thermostat
closes.

CIRCUIT NO.3
SERVICE
LINE
CIRCUIT NO.2
BREAK
THERMOSTAT
TIME SWITCH
STACK
SWITCH
CIRCUIT
3
Fig. 48.-Automatic control power circuit No. 3. The stack switch circuit.
Ans. Since the time switch is normally closed when the
thermostat closes, the circuit is complete and the motor starts
running, but only for a minute or so till the time switch acts
and stops the motor.
650
Oil Burners
rotes
What control is added to prevent the motor stopping if
operating conditions be all right?
Ans. A third circuit is added called the stack switch circuit.
Describe the hook up.
Ans. As shown in fig. 48, the third circuit which includes the
stack switch, is connected to the two terminals of the break.
How does it work?
Ans. The primary purpose of the stack switch is to shut off
the oil supply to the burner if it fail to ignite. Evidently if,
during the interval the time switch allows the motor to run,
the fuel be ignited, the stack will become warm which will cause
the stack switch to close and maintain operation even after the
time switch opens. Again if the fuel do not ignite the stack will
be cold and the stack switch will remain open with result that
as soon as the time switch opens the motor will stop.
Ignition Transformer
This is the source of high voltage for the spark which ignites
the fuel mixture at the burner head. The high voltage terminals
of the transformer are connected to the ignition electrodes by
a pair of flexible connectors.
How much gap is there between the electrode points?
Ans. About 16 inch.
What voltage is required for the spark?
Ans. About 10,000 to 15,000 volts.
Oil Burners
651
The Master Control
The various controls just described must have some device
upon which their operation depends. That is, they must be
OIL SUPPLY

MOTOR COMPRESSOR UNIT
ROTARY OIL AND AIR PUMP
SUMP
SCREEN VALVE
ELECTRIC VALVE
BOTTOM AIR INLET
CHIMNEY CONNECTION
COMBUSTION CHAMBER
SECONDARY HEAT
.RANSFER SURFACE
Fan
Motor
0115
m
·COMBUSTION AIR
Pump
-PRIMARY AIR-
SECONDARY AIR
Fig. 49.-Diagram showing function of the essential parts of the inverted oil
burner of the automatic heating equipment shown in the accompanying
illustrations.
652
Oil Burners
brought into action according to a properly timed cycle and
this is accomplished by the master control. The following relates
to the master control of one of the leading makes of oil burner.
Describe the master control and its functions.
Ans. This is an electrical device which receives signals from
the thermostat, flame detector, limit controls and safety
switches and translates them into the right action at exactly
the right time on the part of the operating and control mecha-
nisms of the furnace.
IGNITION (1)
CAM OPENS
ja pi
a D
DI
K
14 D
bo
B CAM
OPENS
START HERE
OFF POSITION
ALL CAMS OPEN

AT 60 SECONDS] TELECHRON (T)
(T) CAM OPENS CAM CLOSES
-50
ja bi
14
DO
6010
SECONDS
-51½
id bi
od pl
DO
DURING THIS INTERVAL
THE FLAME DETECTOR
MUST TRAVEL FROM
COLDSIDE TO HOTSIDE
S CAM
OPENS
3
A STARTING
CYCLE TAKES
60 SECONDS
4
23 2/2
2012 211/2
NI- NI
1
•
-IN
DI
IGNITION (I)
CAM CLOSES
1
Id A
DI
UU
UU
UU
DI
DO
DI
UUU
Di
START(S)
CAM
CLOSES
R CAM
-CLOSES
-B CAM
CLOSES
R CAM
OPENS
;
Fig. 50. Starting sequence of master control of inverted oil burner automatic
heating boiler.
Oil Burners
653
What does it include?
Ans. It includes a transformer for converting 110 volt house
current to the low voltage required by some of the control
circuits, a relay for closing certain control circuits and a
“two try" safety device whose function is later described.
What else?
Ans. It also contains a cam shaft for opening and closing
electrical contacts, in proper sequence, and a motor which
rotates the cam shaft, the assembly accurately timing every
phase of the starting cycle.
The Starting Cycle
The various events of the starting cycle as performed by the
master control are here given in detail. The starting cycle is
shown in fig. 50. It is necessary to know this sequence in order
to understand the wiring diagrams.
Now describe the starting cycle.
Ans. The various events and their timing are as follows:
1. Three seconds after the cycle starts, the Telechron cam
closes.
This insures that the control will complete the cycle even if the
thermostat open.
2. At 4 seconds the ignition cam closes.
This is merely a pre-setting operation-the ignition does not come
on because A1 contact (see wiring diagram) is open.
3. At 8 seconds, the S cam closes.
This is another pre-setting operation similar to step 2. Note that in
closing, it places a short circuit around the oil valve coil.

654
Oil Burners
4. At 192 seconds the R cam closes. D
This picks up the A relay, which in turn closes A1 contact and starts
the motor compressor and ignition spark.
no lon
5. At 2012 seconds, the B cam closes.
This is a holding circuit for the A relay.
Soals url 24
6. At 212 seconds, the R cam opens.
Recon
This leaves the A relay armature held up through the B cam and
the holding resistor.
7. At 232 seconds the S cam opens.
This removes voltage from the start
winding, and at the same time removes the
short-circuit from the oil valve coil. The oil
valve now picks up (getting its voltage
through the auto-transformer action of the
motor windings) and the flame starts.
N76H
8. At 502 seconds, the B cam opens.
However, before the B cam opens, the
flame detector must have moved to the hot
side contact to maintain the circuit to the
A relay. The diagram shows that there is a
27 second period (from the time the oil
valve opens at 23½ until B opens at 50%)
during which the flame detector contact
must move from the cold to the hot con-
tact. Normally, it accomplished this in 5 to
10 seconds, thus giving plenty of margin.
161
spalk of
Fig. 51. Typical burner head of inverted oil burner showing ignition electrodes..

Oil Burners
655
9. At 512 seconds, the ignition cam opens, turning off
ignition.
Salute vistaitomani
11
10. At 60 seconds, the Telechron cam opens and stops the
cam movement.sroeM tu dood edT
DUST COVER
This finishes the cycle leaving all cams open and ready for another
cycle and leaving only the circuit through the thermostat and flame
detector to the A relay to keep the unit operating.
$ baolad
lola bost of
900s Jon of
CONTACT
STACK ASSEMBLY
RELAY HOLD ING
RESISTOR
116
How long does the unit operate?
Ans. Until the thermostat is satisfied.
TELECHRON MOTOR
FOR DRIVING CAMS
LOW VOLTAGE
CONTROL
TRANSFORMER
3014
Fig. 52.-Master control (side view) for inverted oil burner automatic heating
boiler.
What stops the operation?
Ans. The opening of the circuit by the thermostat (or until
the flame detector "feeling" something wrong with the flame,

656
Oil Burners
opens the circuit) at which time the A relay drops open and
immediately shuts the oil valve and stops the compressor.siy
quite brengo mis mondonlaT ad abno 09.17.01
The Lock Out Mechanism voor m
hom
IM
Suami antys
If, in step 8, the flame detector do not get to the hot side
before B opens (which will happen, if for instance, the flame
do not come on due to lack of oil) a "two-try lockout mecha-
nism" in the control, tallies up one "try" and the control then
repeats the cycle.
厨
​300 301
niloo
LOWER TAPPING
FOR LOW WATER
CUTOFF HOUSING
(STEAM SYSTEMS)
HIGH TEMP
LIMIT SWITCH
DOMESTIC
WATER SWITCH
FLAME
DETECTOR
FLUE PRESSURE
RELIEF SWITCH
Ched
Fig. 53. Rear view of boiler for hot water system showing position of domestic
hot water switch and safety controls forming part of the inverted burner auto-
matic heating boiler equipment.

Oil Burners
657
What happens if the flame be all right?
Ans. If the flame be all right and the flame detector reach
the hot side, the lock nut mechanism resets.
What happens if the flame detector again fail to reach
the hot side?
Ans. The locknut mechanism tallies up two "tries" and opens
the lockout contacts so that the burner cannot re-cycle again
until the reset button is pressed.
What does pressing the rest button do?
Ans. Pressing the reset button for 4 or 5 seconds (until the
T cam closes) allows the control to make two more tries.
Boiler Control Devices
These are also known as limit controls and are a standard.
part of most outfits. They differ according to the type of heat-
ing system to which the furnace is connected.
Name two kinds of limit controls.
Ans. 1, Temperature control; and 2, water level control.
What is the reason for temperature limit control?
Ans. It takes time to heat a room and even if all the radiators
are filled with steam, the thermostat will keep calling for more
heat until the room has become warm. During this interval the
limit control will shut down the furnace before the steam
pressure or temperature reach an unsafe degree, that is, the
pressure or temperature for which the device has been set.

658
Oil Burners
PRESSURE
SWITCH
Sudah le od omul ada
Hot Water Switch
On some outfits there is a thermostatic device which holds
the temperature of the water in the hot water or steam boiler
within pre-determined limits-usually between 160 and 180°.
efu
COMPRESSION
ELBOW
UPPER
HOUSING
ON HOT WATER
SYSTEMS, THE
HIGH TEMPERATURE
LIMIT SWITCH
MOUNTS IN THIS
TAPPING
LOWER
HOUSING
6
EQUALIZER
TUBE
LOW WATER
CUT-OFF
SWITCH
3611
PO
Fig. 54.-Location of switch on model LA lower water cut off switch and
pressure boiler for steam systems forming part of the inverted burner automatic
heating boiler equipment.
Heat is then transferred from the boiler to the domestic hot
water storage tank by means of an indirect water heater. The
location of the domestic hot water switch is shown in fig. 53.

Oil Burners
659
Service Suggestions
noon doit per ETWA MF 70
How should the dial be set?
900
1. Thermostat setting.
Check the thermostat setting to make certain that it has not been
changed accidentally.
bluora nolun9914, 181 W
nismes out
en
ecent slabim zd lange
Figs. 55 and 56.-Flame detector with cover removed.
Ans. The furnace will not run to provide heat unless the dial
be set for a higher temperature than is shown on the ther-
mometer.
How do you test the operation?
Ans. Push the dial setting well above the temperature shown
on the thermometer.
617
The furnace should start in less than one minute. Do not forget to
return the dial to normal after the test.
2. No oil.
013nd 1981
Hoayout mill
Check oil gauge to make certain. The gauge may be inaccurate.
Verify by using a measuring stick.
OF

660
Oil Burners
3. Open switch.
paivase.
In many communities the local Electrical Code requires a switch for
the furnace circuit to be installed at the head of the basement stairs.
Usually there is also a basement light switch in the same location.
What precaution should be taken?
Ans. Make certain that the furnace switch has not been
opened by mistake instead of the light switch.
THERMO-
STAT
CABLE
RESET
BUTT ON
MASTER
CONTROL
IGEITION
TRANS-
FORMER
IGNITION
CON-
NECTORS
FLAME
DETECTOR
POWER LIFE
TIL LINE
SECONDARY AIR DUCT
CANVAS CONNECTOR
COMBUSTION AIR
ADJUSTING NUT
MOTOR
COMPRESSOR
OIL
LINES
BURNER
HEAD
$1GHT
DOOR
LINE
01 PAN
bna 22 api
Soy ob molt
and
Fig. 47. Top view of inverted burner oil furnace (boiler type) with jacket re-
moved to show controls and accessories.
4. Reset button.
If after the foregoing items have been checked and found in normal
condition, the furnace still do not operate, press the reset button for 5
or 10 seconds. The unit should start in less than a minute.
Oil Burners
661

MOTOR
COMPRESSOR
BLACK
GREEN
OIL
VALVE
RED
IGNITION
TRANS-
FORMER
DOE
M
LIMIT
CONTROL
*
I
MASTER CONTROL
TRANSFORMER
LUG ON
RELAY COIL
TELE-
CHRON
RELAY
A
FLUE PRESSURE
SWITCH
O
2
5
RESIST
ANCE
ww
O
RESTART
SWITCH
DISCONNECT
SWITCH
L.MAL.C
POWER
SUPPLY
Fig. 58.-Wiring diagram 1, for inverted burner oil furnace steam or vapor.
FLAME
DETECTOR
DOMESTIC
WATER
SWITCH
(IF USED)
TOROOM
THERMO
STAT
•
662
Oil Burners
If it still do not operate what should be done?
Ans. Check items 5 to 9.
M
If these do not produce results, an experienced service man should
be called in.
IG
7 MOTOR
COMPRESSOR
RUN
~
START
M
mm
ww
RELAY
IGNITION TRANSFORMER
T
R
HOLDING
RESISTOR
OIL
VALVE
S
CONTROL
TRANSFORMER
LOCK
OUT
$
m
T
osta
CH

FLAME
DETECTOR
\INTERLOCK_CAM,
AL
2
FLUE PRESSURE
SWITCH,
LIMIT SWITCH
LOW WATER]
SWITCH
S CAM HERE ON
CR 7865 AIA AIB &
AIC CONTROLS
RESTART
SWITCH
-S CAM HERE ON
CR 7865 AID CONTROL;
:

ROOM
THERMOSTAT]
DOMESTIC
WATER
SWITCH
(IF USED})
C CAM˜IN CR7865 AIC E
AID CONTROLS ONLY
Fig. 49.-Wiring diagram 2, for inverted burner oil furnace steam or vapor.
Oil Burners
663
5. Blown fuse.
Locate the electric fuse that protects the furnace circuit and make
certain that it has not blown.
Keep a spare fuse handy.
6. Low water.
The low water cut off device may have performed its normal function
of disconnecting the electrical circuit because the water in the boiler
is low.
What should be done?
Ans. Replenish the boiler water and the switch will auto-
matically reset.
The water level should be carried at approximately the middle of
the glass gauge.
7. Close time switch.
If the thermostat work in conjunction with a time switch to provide
automatic temperature set back at night, be sure that the time switch
is not 12 hours off.
What provision is made on some dials to prevent this
error?
Ans. The black dot below the time setting knob should show
through the clock dial from 6 p.m. to 6 a.m. and the white dot
from 6 a.m. to 6 p.m.
If this be not the case set the clock 12 hours ahead.
8. Tank valve closed.
In most installations a shut off valve will be found in the oil line
near the point where it enters the basement from an outside tank or
near the outlet of an inside tank. This may have been tampered with
by children or by some unauthorized person. Be sure it is open.
664
Oil Burners

ROOM
THERMOSTAT
BR
BL
JUNCTION
BOX
RED
MOTOR
COMPRESSOR
JUNCTION
BOX
RED
WHITE
BROWN
+
DISCONNECT
SWITCH
BLACK
GREEN
OIL
VALVE
RED
CIRCULATOR
MOTOR
DI D2
POWER
SUPPL
CIRCULATOR
RELAY
IGNITION
TRANS-
FORMER
LIMIT
CONTROL
MASTER COTROL
LH
R
1
S
TRANSFORMER
и
LUG ON
RELAY COIL
TELE -
CHRON
RELAY
RESIST
ANCE
O
FLUE PRESSURE
SWITCH (IF USED)
Fig. 50.-Wiring diagram 3, for inverted burner oil furnace hot water.
RESTART
SWITCH
FLAME
DETECTOR
DOMESTIC
WATER
SWITCH
KIF USED)
Oil Burners
665
9. Flue pressure switch.
If the flue pressure switch be open, reclose it and observe the results.
If the furnace start and run normally, nothing need be done.
What should be done if it do not start or run properly?
Ans. Open the line switch and call a service man.
If the flue pressure switch open periodically a service man should
be called even if the furnace apparently run properly every time the
switch is reclosed.
Troubles
1. Burner will not start.
a. Thermostat contacts need cleaning..
b. Main switch not closed.
c. Thermostat located in warm place.
2. Burner will not stop.
a. Thermostat located in a cold place.
b. Short or ground in thermostat cable.
c. Thermostat contacts stuck.
d. Armature of stack relay stuck in closed position.
3. Not sufficient heat.
a. Defective thermostat.
b. Improper location of thermostat.
c. Defective heating equipment.
4. Burner starts but flame blows out.
a. Water in oil.
b. Excessive air. .
c. Chamber too small.
d. Nozzle too small.
666
Oil Burners
5. Burner starts but fails
to continue.
a. Lack of oil.
b. Dirty nozzle or strainer.
c. Helix does not expand
rapidly enough.
d. Closed valves.
e. Leak in oil inlet line.
LG
WATER
CIRCULATOR
MOTOR
COMPRESSOR
R
ww
супу
RELAY
IGNITION TRANSFORMER
T
R
OIL
VALVE
.S
www
рми
hum
RELAY
D
~
HOLDING
RESISTOR
LOCK
OUT
CONTROL
TRANSFORMER
m
5
S
LH
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1
6. Ignition trouble.
a. Spark gap too wide.
b. Cracked porcelains.
c. Electrode tips in path of oil
ROOM
DI
spray.
d. Electrodes grounded on air
tube.
e. Check transformer.

THERMOSTAT
8
FLAME
DETECTOR
INTERLOCK CAM
2
2
FLUE PRESSURE
SWITCH
(IF USED)
gLIMIT, SWITCH
S CAM HERE ON
CR7865AIA, AIB &
AIC CONTROLS
“S” CAM HERE ON
CR7865AID CONTROL

RESTART
SWITCH
DOMESTIC
WATER
SWITCH
(IF USED)
"C" CAM IN CR7865 AIC &
AID CONTROL ONLY
Fig. 51.-Wiring diagram 4, for inverted burner oil furnace hot water.
Oil Burners
667
7. Smoke pipe too hot.
a. Boiler too small (as usual).
b. Excessive draught.
c. Flame too large.
8. High oil consumption.
a. Outside weather severe.
b. Thermostat setting too high.
c. Leakage through doors and windows.
d. Too frequent opening of doors.
9. Smoke coming from chimney.
a. Improper combustion.
b. Improper grade of oil for burner.
c. Clogged flue passage.
10. Motor will not start.
a. Check for open circuit defective starting switch or fault in winding
b. Pump stuck.
c. Check wiring going to motor.
Operating Information.
The following are the pressures and temperatures at which the
controls of the system shown on page 651 are normally set:
15 lbs.
.170° F.
5 lbs.
7 oz.
220° F.
1. Sump pressure (motor compressor)..
2. Domestic water switch (typical setting) trip...
3. Pressure limit switch (typical setting) trip.
Vapor pressure limit switch (typical setting) trip...
Hot water limit switch (typical setting) trip
4. Fan and limit switch
Typical settings:
668
Oil Burners
Fan off....
Fan on..
Flame on.
Flame off.
·
110° F.
.150° F.
.175° F.
..200° F.
1. Sump pressure is measured by inserting a tee in the air line to
the burner head (at a point which is marked "Air Outlet") and con-
necting to this tee a guage with a range that will allow 15 lbs. to be
read accurately. Pressure is always measured with the unit running
and the flame on. The pressure is changed by means of the screw on
the air pressure regulator.
2. The trip setting of the domestic water switch is controlled by a
slotted knob which can be turned with a screwdriver. Although there
is a temperature scale by the knob, it is sometimes desirable to ignore
the scale and set the knob at that point which provides a satisfactory
domestic water temperature. Remember these points:
a. On a steam system, if the domestic water setting be too high, steam
may be generated and forced to the radiators when it is not wanted.
Thus, the maximum setting is limited by the point at which the
furnace begins to produce steam on the domestic water cycle.
b. When a steam furnace runs on house-heating cycles, the boiler
water temperature is 212 deg. F., or above, and the domestic water
will be considerably hotter than when the furnace runs only for
domestic water heating. Changing the switch knob cannot prevent
this higher temperature of the domestic water during the cold
season-it can only keep the water temperature from going below
a certain value.
c. In a hot water system, do not expect the thermometer on the front
of the furnace to agree with the knob setting-there may be a con-
siderable different "time lag" in the response of these two instru-
ments due to the "dry wells" used in mounting them in the hot
water boiler.
3. Ordinarily, there is little necessity for ever changing the setting
of the steam, vapor, or hot water limit switch. These are protective
devices and normally never operate unless the furnace rating is con-
siderably greater than the radiation connected to it, or unless they
operate to protect the furnace because of trouble elsewhere in the
system.
Oil Burners
669
4. On a warm air furnace, the fan and limit switch controls
the starting and stopping of the fan and also acts as a safety
device to stop the flame if the air overheat. The normal
sequence of events on a warm air furnace is as follows:
a. The control cycles and the flame starts.
b. When the unit has warmed up enough so that the fan will not blow
cold air through the ducts, the fan switch starts the fan motor.
c. When the thermostat is satisfied, the flame stops. The fan con-
tinues to run until most of the stored heat is removed from the
furnace.
d. The fan switch stops the fan before the air temperature gets so low
that the air from the grilles feels cool.
e. If, when the flame and fan are on, the air temperature rises unduly
because of restricted air flow, (due to dirty filters, for instance)
the limit switch stops the flame. The fan, however, continues to run,
thereby bringing down the excess temperature. When the air tem-
perature is reduced, the flame comes on again. Other factors that
might cause the limit switch to operate are: low air flow because
of too many grilles closed off, broken fan belt, burned-out fan
motor, etc.
Generally, it is not necessary to change the limit switch set-
tings from the values given in the list on page 668. However,
it may be desirable to shift the fan switch settings under the
following circumstances:
1. If the air issuing from the grilles feel too cool before the fan
shuts off at the end of a cycle, it may be desirable to raise the "fan off"
setting above the normal 110° F. (Air issuing from the grilles is not
"too cool" unless it create noticeable drafts in the room.) To prevent
re-cycling of the fan during the warm-up period, it may then be neces-
sary to raise the "fan on" setting the same amount that the "off"
setting was raised.
2. If the fan recycle when it first comes on, it may be a fault in the
switch, or it may require only that there be more differential between
"on" and "off." The 150° F. setting can be raised some, or if the air
do not begin to feel too cool on shutdown, the 110° F. setting can
be lowered.
670
Oil Burners
Remember that there will always be a certain amount of
cool air in the ducts that will be blown out when the fan first
starts, and no change in fan switch setting can prevent this.
The burner is provided with a fan and limit switch. To change any of
the settings, it is necessary only to loosen the knurled nut and move the
pointers to the desired values on the scale. The lowest pointer is the
"fan off," the next is the "fan on," the next is the "flame on," and
the highest pointer is the "flame off."
THE FLAME-As stated previously, the CO2 content in
the combustion chamber is a measure of the amount of air
being supplied per pound of fuel and is generally limited to 12
per cent maximum. Eleven per cent is considered a good all-
around figure from the standpoint of efficiency and cleanliness.
If the means of measuring CO₂ be available, it is the best way
to adjust the flame. A good flame has the following charac-
teristics:
1. It should be of a soft yellow-orange color and fairly transparent.
(For a few inches just below the nozzle it is usually blue.)
It travels downward in a spreading cone to the bottom of the com-
bustion chamber and then turns upward at the outer edge with tails
of flame which rise part way back up into the chamber. These tails
should thin out and disappear without leaving any visible traces of
smoke.
TOO MUCH AIR makes the flame harsh, with a bright yellow
color, and shortens the tails so that the flame appears to end at the
bottom of the chamber without turning back on itself.
TOO LITTLE AIR makes the flame dull, with a dirty reddish-
orange color, and causes it to expand so that it appears to fill the
combustion chamber. The tails turning back on the cone appear
smoky and can be seen going into the secondary passages with com-
bustion incomplete.
Adjustment of the air is accomplished by means of the disc on the
fan of the motor compressor. (See fig. 47.)
Condensers
671
→
CHAPTER 36
Condensers
What is a condenser?
Ans. An appliance designed primarily for removing the back
pressure upon an engine or turbine.
How is this accomplished?
Ans. By cooling exhaust steam and converting it into water.
What is the object of reducing the back pressure on a
steam engine or turbine?
Ans. To obtain better economy.
Explain why.
Ans. A single pound of steam under an absolute pressure
corresponding to one half inch vacuum has a volume of 1208
cu. ft. while a single pound of water has a volume of .016 cu. ft.
Thus when steam at that pressure is condensed the reduction.
in volume is in the proportion of over 75,500 to one and this
is what reduces the pressure.
What is a vacuum?
Ans. A space devoid of matter, that is, a space in which the
pressure is zero absolute.
672
Condensers
What is the economy due to condensing?
Ans. It is held in the popular mind that the economy of con-
densing is, in round numbers, 25 per cent. This percentage
usually relates to simple engines and it refers to the economy
as measured by the difference in the coal consumption pro-
duced by a condenser. The evidence of some of Barrus' tests
show that "this belief is not well founded except in special cases.
A
94.7
147
G
R
.2151 LB. STEAM PER STROKE
ATMOSPHERIC LINE
M
80
14.7
E &
2
S'
.1829 LB. STEAM PER STROKE
M
""


ZERO LINE
ZERO LINE
CONDENSER LINE
Figs. 1 and 2.-Theoretical diagrams for equal power of throttling engines
operating non-condensing (sometimes ill-advisedly called “high pressure")
as in fig. 1 and condensing as in fig. 2. It should be distinctly understood
that these are theoretical cards for engines without clearance being shown
for simplicity and in practice the actual saving by condensing depends on many
conditions. The solid black area M, is due to the condenser; hence, it must
be evident that in governing by throttling when changing from non-condensing
to condensing operation, the initial pressure is lowered until the card area S'
and M (fig. 2) is equal to S (fig. 1) thus maintaining constant load. Also
if the initial pressure remained the same and condenser be added, the card
area S, would be increased by the area M, giving card LARFG (fig. 1)
increasing the power by area M This is one way of increasing the power
of an engine.
What shows that this belief is not well founded?
Ans. If the feed water be heated by the exhaust steam of
the non-condensing engine to a temperature of 100° Fahr.,
which is that of the ordinary hot well, to a temperature of 210°
Fahr., the non-condensing engine can be credited with about
Condensers
673
11 per cent less coal consumption, which should be considered
in determining condenser economy.
What did Barrus' tests show?
Ans. The average of a number of Barrus' tests gives a saving
produced by condensing of 22.3 per cent. "If we allow for the
steam or power used by an economical condenser, it would be
seen that the net economy of condensing is at best not much
over 20 per cent, based on steam consumption. If furthermore,
we allow for the difference produced by heating the feed water
to the extent afore mentioned, the saving of fuel would be
reduced to about 10 per cent."
What is the gain in power due to condensing?
Ans. According to C. H. Wheeler "changing over a single ex-
pansion reciprocating engine from non-condensing to conden-
sing operation amounts to from twenty to thirty per cent."
What does Wheeler mean by single expansion engine?
Ans. Single stage expansion engine.
In fact in engines of this type there are three to four expansions
non-condensing and five to seven condensing.
Since better economy is gained by expanding steam why
isn't the expansion carried further in single stage ex-
pansion engines?
Ans. Because of the higher range of temperature which causes
additional loss by condensation.
How does the higher temperature range increase con-
densation?
Ans. Re-evaporation between cut-off and pre-release is
-
674
Condensers
increased and its effect is to cool the cylinder walls, which in
turn increases initial condensation.
What auxiliary must be connected to a condenser to
make it work?
Ans. An air pump.
What does the air pump do?
94.7
127
L
14 CUT OFF
EQUAL
ATMOSPHERIC LINE
ZERO LINE
.94.7
94.T
14.7
}
7 CUT OFF


Σ
AREAS
94.7
S
Figs. 3 and 4.-Theoretical diagrams for equal power of an automatic cut off
engine operating non-condensing, as in fig. 3, and condensing as in fig. 4.
Here the area of the card remains the same, but its contour changes. The
solid black portion S, is the portion due to condensing, hence to keep the
power constant the portion M, above the atmospheric line is reduced by short-
ening the cut off till M + $ = L. The cut offs here shown: 4 non-con-
densing, and ¹/; condensing are usually the most economical cut offs.
7
Ans. It should be understood once and for all that the air
pump does not create the vacuum but only maintains it.
In fact any first class surface condensing equipment in good operating
condition can be operated without any air pump for a considerable
length of time without any substantial loss of vacuum.
Why is the air pump necessary to maintain the vacuum?
Ans. The inherent reason is that water contains mechanically
Condensers
675
1
20
mixed with it or 5 per cent of its volume of air at atmos-
pheric pressure and this air must be removed as fast as it collects
otherwise the accumulation of air would gradually build up a
pressure which in time would rise to atmospheric and higher,
thus destroying the vacuum created by the condenser.
Give another reason for an air pump.
Ans. In practice there is always more or less air leakage
through stuffing boxes, joints, etc., and this air as well as the
air of condensation must be removed.
Why does hot air flow into the condenser?
Ans. Because of pressure difference, that is, the pressure in
the condenser is less than atmospheric pressure.
What name is ignorantly and otherwise used for air
pump?
Ans. "Vacuum pump."
There is no such thing as a vacuum pump.
Why shouldn't an air pump be called a vacuum pump?
Ans. Because no pump can "pump a vacuum."
What then does the pump pump?
Ans. It pumps out most of the air (or other gas) from the
condenser maintaining a (partial) vacuum.
What is this vacuum ordinarily called?
Ans. A vacuum regardless of its pressure.
Why does an air pump not extract all the air and obtain
a perfect vacuum?
676
Condensers
Ans. Each stroke of the air pump piston or plunger removes
only a certain fraction of the air, depending upon the percentage
of clearance in the pump cylinder, resistance of valves, etc.;
hence theoretically an infinite number of strokes would be
necessary to obtain a perfect vacuum, not considering resistance
of the valves.
Give another reason.
Ans. Inherent imperfection of the machine. Thus, as just
mentioned, in the common form the exhaustion is limited to
the point where the remaining air has not sufficient elasticity
to raise the valves.
Why are air pumps sometimes purposely called vacuum
pumps by people not of the ignorantia class?
Ans. Manufacturers for instance, who know perfectly well
that the term vacuum pump is incorrect, frequently are forced
to use it, even in print, because if they didn't many of their
customers wouldn't know what they were talking about.
How is the degree of vacuum measured?
Ans. In terms of inches of mercury.
See Chapter 1 for full information on vacuum, absolute, and gauge
pressures, etc.
Into what two general classes may condensers be classed
with respect to the method of heat transfer from the
steam to the "cooling" water?
Ans. The two classes are as given on the page following.
Note different names for the two classes.
Condensers
677
CLASS 1
1. Direct contact (jet condensers)
CLASS 2
2. Surface contact (surface condensers)
What should be noted about these two classes?
Ans. There is a multiplicity of types of each class.
Class 1. Condensers
(Jet and Barometric Condensers)
Name two important types of Class 1 condenser.
Ans. Low level or jet condensers and high level or barometric
condensers.
What is a jet condenser?
Ans. A closed chamber within which exhaust steam comes in
direct contact with a spray or jet of cold water and is condensed.
What is the cold water called and why?
Ans. The injection water, because it is "injected" into the
condenser.
What happens when the exhaust steam comes into con-
tact with the finely divided injection water?
Ans. It is almost instantly condensed.
678
Condensers
Why not instantly condensed?
Ans. It is impossible for any physical act to take place
instantaneously.
This is directed especially against such alleged articles advertised
as instantaneous water heaters, instantaneous (cooking) breakfast foods,
etc. Such advertising is misleading, ridiculous, but doesn't fool anyone.
What happens when condensation takes place?

JET
CONDENSER
COOLING WATER
STEAM FROM ENGINE
CONDENSATION
PRODUCES VACUUM
PUMP FOR REMOVING
INJECTION WATER
CONDENSATE AND AIR
AIR AND HOT WATER
DISCHARGE
Fig. 5.-Elementary jet condenser showing essential parts. The pump at the
right is a so called air pump and ignorantly called "vacuum pump" under
the supposition that the pump produces the vacuum. It is, strictly speaking,
a combined injection water, condensate and air pump.
Ans. Since each cu. ft. of exhaust steam shrinks to about
1 cu. in. of water when condensed, a (partially) empty space
or (partial) vacuum is created in the condenser.
Upon what does the actual shrinkage depend?
Ans. The degree of vacuum in the condenser.
聚
​Condensers
679
What causes the injection water to enter the condenser?
Ans. When the condenser is not too high, atmospheric
pressure forces it in; when higher than the barometric column,
a pump is required.
PARALLEL FLOW
CONTRACTED AREA
VACUUM BREAKER-
CONDENSING CHAMBER-
B
C
INJECTION WATER, CONDENSATE
AIR AND NON-CONDENSABLE VAPORS
WET AIR PUMP
Wil

PUP
ANGKIRJA.
F
STEAM
-A
PUMP
DISCHARGE
Fig. 6.-Parallel flow condenser. It consists of a conical or bottle shaped
casting projecting down into the water end of the air pump, and having open-
ings in its upper parts for steam and cooling water. In operation, the exhaust
from the engine enters the condensing chamber at A, and the injection water
at B. C, is the spray pipe which has at its lower extremity a number of vertical
slits through which the water passes and becomes spread into thin sheets.
The spray cone D, breaks the water passing over it into a fine spray, and
thus causes a rapid and thorough mixture of the steam and water. The spray
cone is adjusted to give the proper amount of water by means of a stem passing
through the top of the condenser to wheel E. The injection water and con-
densed steam fall together through the opening F, into the pump and are dis-
charged into a convenient waste pipe, or into a hot well when the discharge
water is to be used for feeding the boilers.
680
Condensers
What is a "barometric column"?
Ans. See barometers, Chapter 1.
What must be removed from the condenser in addition
to the condensate and injection water?
Ans. A small amount of air.

COOLING
WATER
»
STEAM
Lyk₁
TO DRY AIR PUMP
AIR AND UNCONDENSED
VAPOR
DISTRIBUTION TROUGHS
COUNTER
FLOW
TO INJECTOR
WATER PUMP
Fig. 7.-Counter-flow "jet" condenser. In this arrangement the steam
and water flow in opposite directions, that is, the entering steam encounters
the warmest water and condenses as it rises, passing through successive curtains
of water, obtained by suitably arranged overflow trays. Thus the temperature
of the vapors is gradually reduced as they approach the top of the condenser,
due to the proximity of the incoming injection water. Ultimately the mixture
entering the pipe to the dry air pump consists of air of relatively high density
compared with that of the residual water vapors.
Condensers
681
What means is provided to remove the water and air?
Ans. A wet air "removal" pump.
What is a (wet air) "removal" pump?
Ans. One which pumps both water and air from a condenser.
SPRAY
PIECE
For a jet condenser the wet air pump removes from the condenser:
1, condensate; 2, injection water; and 3, air, and for a surface condenser
it handles only: 1, condensate; and 2, air, being called a removal pump
with jet condensers, but called a wet air pump with surface condensers.
STEAM

COOLING
WATER
AIR
A
B
COUNTER FLOW
PARALLEL FLOW
TO DRY AIR PUMP
TO WATER REMOVAL
PUMP
Fig. 8.-Combined counter flow and parallel flow jet condenser.
Why is a wet air pump for a jet condenser considerably
larger than a wet air pump for a surface condenser?
Ans. Because of the large amount of injection water that
must be removed.
682
Condensers
What is a jet condenser?
Ans. A chamber or vessel within which exhaust steam meets
a spray or "jet" of water and is condensed. The heated injection

INJECTION
WATER
REDUCED
CONTACT
SURFACE
A---
CONSTRICTED
NECK
EXHAUST
STEAM
ग
--B
SPRAY
CONE
17
Fig. 9.-Low level parallel flow jet condenser showing the method of reduced
contact surface vacuum breaker. In construction the neck or upper part
of the condenser chamber is made quite small and the cross sectional passage
area is further constricted at this point by the cooling water pipe. In coera-
tion, rapid condensation is due only to the large surface exposed by the
cooling water as it passes through the large section of the condensing chamber.
Due to the constricted neck, any accumulation of water rapidly diminishes
the condensing surface until the spray cone itself is submerged, leaving only
the small annular ring of water at AB, to act on the large volume of entering
steam. The surface of this ring being far too small to condense the steam,
the pressure immediately rises causing the relief valve between the engine
and condenser to open and allow engine to run non-condensing, or in the
absence of a relief valve the exhaust steam will blow out through the cooling
water pipe and pump valves, thus forcing all the water out of the condenser.
Condensers
683
EXHAUST INLET
water, condensate and liberated air are removed from the con-
denser by the wet air (removal) pump which delivers the water
into the hot well, whence the feed pump supply is pumped into
the boiler the surplus escaping through the overflow.

A
INJECTION
老
​ADJUSTABLE CONE
AIR ADMISSION
P AIR
VALVE
F
V
B
Fig. 10.-Low level combined counter and parallel flow condenser showing
typical example of air admission vacuum breaker. It consists of a separate
and communicating chamber with float operating an air valve which admits
air into the condenser. In operation, when the water rises in the condenser
to the level AB, it lifts the float F, which in turn lifts the air valve V, from its
seat, admitting air into the condenser through pipe P, thus breaking the
vacuum.
684
Condensers
On large size jet condensers what is sometimes used to
remove the air?
Ans. A dry air pump.
What is a dry air pump?
Ans. A pump designed to handle air and gases only, which
restricted service permits construction such as will give a higher
vacuum than possible with a wet air pump.
What are the essential features of construction?
Ans. The valves are exceptionally light and the valve spring
no stronger than required to insure proper seating of the valve.
Moreover the clearance is very small.
What do you mean by the clearance?
Ans. The volume between the piston and valves when the
piston is at the end of the discharge stroke.
How is the pump designed for minimum clearance?
Ans. The valves are placed in the cylinder heads and in some
special construction the heads themselves form the valves.
For the limit of minimum clearance see the author's "zero clearance"
wet air pump, pages 692 and 695.
What is frequently used in place of dry air pumps and
why?
Ans. Steam ejectors. They are adapted to service where
relatively large quantities of condensable vapors can be condensed
in a "pre-cooler" ahead of the condenser.
Owing to the importance of steam ejectors especially in large turbine
plants additional information will be given in the next chapter.
Condensers
685
1.50″ OF MERCURY
ABSOLUTE PRESSURE
What important automatic device is necessary for safety
with jet condensers?

70°F.
VACUUM
BREAKER
GAUGE
GLASS
·····
ŞA MALLOL.
STEAM
પા,
*!!!!
**
2.03
***
91.7 F
AIR
88°F.
INJECTION
WATER 70°F
Fig. 11.-Cross section of a modern low level jet condenser with temperatures:
indicated to show condition of operation.
686
Condensers
Ans. A vacuum breaker.
What is a vacuum breaker?
Ans. An automatic device to protect the main engine or
turbine from flooding.
Why?

INJECTION WATER
FORCED
INJECTION
WATER INLET
Chat
VACUUM
BREAKER
Fig. 12.-Method of connecting vacuum breaker to the injection water inlet
line on a low level jet condensing equipment. The connection to the water
line should be at its highest point.
Condensers
687
Ans. It is necessary if the water removal pump fail.
What do you mean by a water removal pump?
Ans. A wet air pump connected to a jet condenser which
removes: 1, the condensate; 2, the air, and 3, especially the
injection water.
Why is a vacuum breaker of such importance?
Ans. At the usual rate of flow of the injection water, a jet
condenser would be filled with water in a few seconds should
the pump slow down unless provision be made to break the
vacuum and thereby stop the incoming water.
What do the numerous types of vacuum breaker depend
upon for automatic action?
Ans. 1, Reduced contact surface; and 2, air admission.
How does the reduced surface breaker work?
Ans. It consists simply of a constricted neck at the upper
part of the condensing chamber which with undue rise of the
injection water causes the condensing surface to rapidly di-
minish so that it is inadequate to condense the steam, thus
causing the pressure to rise within the condenser.
How does the air admission type work?
Ans. It consists usually of a ball float, placed either in the
condenser proper, or in an adjoining and communicating
chamber and which, upon flooding of the condenser, will operate
a valve and allow air to enter the condensing chamber, thus
destroying the vacuum.
Where should the air be admitted for most efficiently
breaking the vacuum?
Ans. In the water injection line.
688
Condensers
PARALLEL
FLOW
STEAM
DANGER LEVEL-
34 FT.
B
OUTER
CONE
HYONOPLINE
KALI-KLI
TIJL
COMBINING.
TUBE
RELIEF VALVE
COOLING
WATER
A
WORKING
LEVEL
OVERFLOW PIPE
TAIL PIPE
D
WHOA!
HOT-WEL
NOZZLE OR INNER CONE D
LIMETERLISTAALINEN DORTM
INJECTION PIPE
DZMERNORSKE
COUNTER FLOW
AIR OUTLET

Vu
MIPLEHOLM
20 F.T. OR LESS
-INJECTION PIPE
FESTDIESELFOODMOHI DOLOHODA.SI
20 FT. OR LESS
STEAM
INJECTION OR
COOLING WATER
SUPPLY
OVERFLOW
-34 FT.
TAIL PIPE
HOT WELL
DRY
AIR
PUMP
Fig. 13.-Parallel flow barometric condenser or so-called injector condenser.
Fig. 14.-Counter flow barometric condenser or dry air pump type.
Condensers
689
Barometric Condensers
What is a barometric condenser?
Ans. A high level jet condenser.
What takes the place of the removal pump?
Ans. A tail pipe of comparatively large diameter and over
34 ft. long attached to the condenser and submerged at its
lower end in a hot well.
How does it remove the water without a pump?
Ans. Due to the length of the tail pipe the weight of the
column of water in the tail pipe overbalances the pressure of
the atmosphere (at maximum barometer reading) and accord-
ingly the injection water flows out of the condenser.
Name two types of barometric condenser.
Ans. 1, The parallel flow or so called injector type, and
2, the counter flow or dry air pump type.
What name is sometimes given to the parallel flow type?
Ans. The ejector barometric condenser.
Class 2. Surface Condensers
What is a surface condenser?
Ans. A device for condensing steam in which the steam and
cooling water do not come into contact with each other, but are
separated by metal surfaces.
What name is given to the cooling water and why?
690
Condensers
Ans. It is called the circulating water because it is "cir-
culated" on the water side of the cooling surface.
Name some types of surface condenser.
Ans. 1, Keel; 2, bastard; 3, box; 4, inboard; 5, wet; 6, dry;
7, water works; 8, evaporative; 9, single pass; 10, two pass;
11, single flow; 12, double flow; 13, multi flow, etc.
EXHAUST
PIPE
USUALLY SINGLE PIPE
CONDENSATE PUMP
CONDENSATE
HOT WELL
Fig. 15.-Bastard keel condenser. A makeshift nondescript contraption.
COOLING WATER
PIPE FITTING

What is a keel condenser?
Ans. A type of marine outboard single pass surface condenser
attached to the side of a hull below the water line.
What are the features of the keel condenser?
Ans. It requires no circulating pump.
What is its application?
Ans. It is suitable for small vessels.
What is a bastard condenser?
Ans. An atmospheric keel condenser.
Condensers
691
What is the application of bastard condensers?
Ans. They are sometimes fitted to canal boats or other
nondescript vessels.
W
Why?
Ans. Owing to the ignorance of the owner-in fact such make-
shift apparatus operating without vacuum is inexcusable.

R
RAND L NIPPLE
STANDARD PIPE
EXHAUST END
M
S
TO AIR PUMP
TIGHT FIT
THREAD
What is a vacuum keel condenser?
CONDENSATE
END

PLATE
WASHER
AND
LOCK NUT
PLATE
Figs. 16 and 17.-Ordinary keel condensers made of standard pipe and fittings.
Fig. 16, assembly on boat; fig. 17, construction details. The exhaust should be
piped through the hull at M, very near the water line so that there will be as
much pitch as possible between M and S, as it should be remembered that
thorough and quick drainage is very important to keel condensers
What other reason?
Ans. The frightful fear of some people of spending a couple
of dollars for an air pump?.
692
Condensers
Ans. A type of keel condenser having tubular condensing sur-
face, a return pipe for the condensate, the end of which connects
with a wet air pump.
Why don't these condensers "work" as a rule?
Ans. Usually they don't know enough to install them so that
they drain from beginning to end.
DISCHARGE
ZERO CLEARANCE
AIR PUMP

HULL PLANKING
ރ
CONDENSER RETURN
AIR PUMP INLET
ANGLE FLANGE
(CAST INTEGRAL WITH PUMP)
Fig. 18.-Author's method of getting the air pump inlet below a keel condenser in
order that the condensate will drain into the pump; an important condition for
obtaining high vacuum, and one usually overlooked in most installations.
The air pump instead of being attached to the bed plate, is located at con-
siderably lower level by means of a special casting which projects through
the hull, being secured by an outboard flange (forming part of the casting)
which forms a tight joint as shown. With this arrangement the inlet valve is
at the lowest level of the return pipe thus securing the ideal working conditions.
Proposed arrangement for author's steamer Stornoway II.
Even if they do drain, why can't a respectable vacuum
be obtained?
Condensers
693
Ans. It's impossible with ordinary designs to locate the air
pump at the lowest point of the system.
BAFFLE
It must be evident for good vacuum, any condenser should drain so
that the intake valves of the air pump are flooded with condensate.
These conditions are obtained with the author's special design low
level wet air pump. See page 692.
What is a box condenser?
CIRCULATION
·TO AIR PUMP
EXHAUST FROM ENGINE
CIRCULATING WATER CONNECTION
FEED WATER HEATER

CONDENSER
"BOX"
OVER FLOW
1
BAFFLE
ENGINE
ELEVATION OF AIR PUMP
(BELOW CONDENSER)
Figs. 19 and 20.—Author's design for a box condenser. Note the considerable
pitch with special return bends and the baffles for directed flow of the cir-
culating or cooling water.
Ans. A type used to avoid the drainage difficulty inherent
with keel condensers. It consists of cooling surface placed in a
box, the latter being mounted to the inside of the boat at an
694
Condensers
elevation such that the condensate will drain to the air pump;
a circulating pump is provided to obtain a continuous flow of
cooling water.
A bastard or non-condensing type of box condenser was used on sail-
ing vessels to save the condensate from deck engines.
EXHAUST STEAM INLET
HANDHOLE
D
BAFFLE-
B
WATER
OUTLET

11.
KE
Ἐ
CHANDHOLES
HANDHOLES
CONDENSED STEAM HANDHOLE
OUTLET
WATER INLET
Fig. 21.-Single tube standard condenser. In construction, the tubes are
commonly made 3/4 inch outside diameter of solid drawn brass tinned on both
sides. To allow unequal expansion of the shell and tubes screwed glands and
stuffing boxes are provided; these are packed with cotton cord or corset lacing.
The tube sheets or plates to which the ends of the tubes are attached are of
brass and usually from 1.1 to 1½ times the diameter of the tube in thickness.
The type of joint determines the thickness. With screwed glands a thinner
plate may be used than when the packing extends through it. Usually the
tubes are spaced in a zigzag manner, pitched from 1.5 to 1.7 of their diameter
on centers. The tubes, plate, ferrules, nuts and washers should be of brass to
prevent corrosion. The shell is generally made of cast iron; no wrought iron
should be used when the parts are exposed to the distilled water.
What is a scoop condenser?
Ans. A type of marine condenser with a flow of circulating
water induced through an enclosed chamber by the movement of
the vessel, rather than externally as with a keel condenser.

Condensers
695
9/68
8/59
SCALE
HALF
SIZE
-1/32
4/8
-3/4
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24
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BAARADO
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ヤイトー
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7/32
-R7/16
1,5%
-2%
./½•
$1.38
13 DRILL
32
IIN. PIPE TAP
14 PIPE TAP
What is essential for ade-
quate circulation of the cool-
ing water?
Ans. Fast speed.
On condensers of this type
why should an auxiliary cir-
culating pump be provided?
Ans. To circulate sufficient
water through the condenser
when the vessel moves slowly
into port.
What is an inboard surface
condenser?
Ans. The name inboard is
used to distinguish this im-
portant form of surface con-
denser from the keel type.
Owing to its importance the
term surface condenser means in-
board surface condenser.
Figs. 22 and 23.-Graham "Zero clearence" engine driven air pump for
steamer Stormoway II, adapted to installations where the hot well inlet is
below the level of the air pump discharge. The bucket valve is always under
a head of water, hence is water sealed at all times. The arrangement of the
valves permits of practically zero clearance by close adjustment, hence all the
air is forced out of the barrel on each down stroke, thus tending to produce
the maximum vacuum. In operation, the condensate oozes out of the
multiplicity of small holes drilled in the top of the hollow plunger and flows
to hot well by gravity. The stuffing box is water sealed.
969
Condensers

Somy.
AIR PUMP
CIRCULATING
PUMP
f
T
Fig. 24.-Assembly of condenser and wet air pump and circulating pump.
Into what two classes are surface condensers broadly divided?
Ans. 1, Wet, and 2, dry.
最愛
​180 COD
TOIM
Condensers
697
What is the distinction between a wet and a dry surface
condenser?
LARGE
TUBE
PLATE
Ans. A wet condenser has a common opening for the dis-
charge of the condensate and air. A dry condenser has separate
openings for the discharge of condensate and air.
What do you say about the term dry condenser?
DIFFUSION PLATE
WATER
SUPPLY

SMALL
TUBE
PLATE
WATER
DISCHARGE
STEAM
ENTRANCE
STEAM DISCHARGE
Fig. 25.-Miller double tube condenser (patented in 1869). In construction,
small tubes are placed inside of large ones. The water first passes through
the inner tubes and returns through the outer tubes, and after absorbing the
heat from the steam, is discharged into air pump. This type was extensively
used at one time, but at present the single tube represents the prevailing practice.
Ans. It is a misnomer as the condenser inside is anything
but dry regardless of the type of pump.
Describe the water and steam flow in standard con-
densers.
How about the flow in a water works condenser?
-N
Ans. The water flows through the tubes while the exhaust
steam flows over the outside surface of the tubes and is there
condensed..
698
Condensers

ALKOL
EXHAUST STEAM INLET
VIND{INMIPS
DRY VACUUM PUMP OUTLET
Billi
CONDENSATE PUMP OUTLET
:
CIRCULATING
WATER OUTLET
CIRCULATING
WATER INLET
Fig. 26.-Two (water) pass high vacuum dry condenser.
Ans. It's reversed, that is, the water flows over the outside of the tubes and the
steam flows through the tubes and is condensed therein.
What are the advantages of the surface condenser as compared with jet
condensers?
Condensers
699
Ans. It permits the use of impure or salt cooling water in
marine practice without bringing same into contact with the
condensate, hence the condensate is available for use as boiler
feed.
What is the usual assembly of pumps for a marine wet
condenser?
FAN
Ans. Wet air pump, circulating pump and steam unit direct
drive tandem connected, that is, the three pistons threaded on
one connecting rod.
COOLING WATER SPRAY
Fig. 27.-Evaporative condenser.
CONDENSATE
STEAM

What is the feature of this arrangement?
Ans. The air pump being underneath the condenser the con-
densate simply drops by gravity into the air pump. In fact
there is a head of condensate (negative lift) on the inlet valves
so that the maximum vacuum within the range of the air
is easily obtained.
pump
700
Condensers
What is an evaporative condenser?
Ans. A condenser in which the cooling surface is kept. cool
by the evaporation of the cooling water which is sprayed over
the outer surfaces of the tubes, the evaporation usually being
increased by an air blast.
ONE PASS
WATER OUTLET

TWO PASS
WATER INLET

WATER OUTLET
WATER INLET
Figs. 28 and 29.-One and two pass condensers. It should be noted that the
word "pass" relates to the water circuit and not the steam circuit. Steam circuit
not shown in these diagrams.
Condensers
701
SINGLE FLOW

STEAM INLET
STEAM
F
Fig. 30.-Single flow condenser The steam finds its air path from steam inlet
to condensate outlet with result that the condensing process and vacuum
obtained is not as efficient as might be otherwise. Arrangement sometimes
used on small condensers.
CONDENSATE OUTLET.
DIVIDED FLOW
ヲ
​BAFFLE

BAFFLE
1F
CONDENSATE
Fig. 31.—Divided flow condenser. Note placement of baffle plate causing
steam to flow toward the two ends, then downward and converging toward
the condensate outlet.
702
Condensers
Condenser Tubes
What materials are used for condenser tubes?
Ans. The material most commonly used is Muntz metal for
fresh water and Admiralty metal for salt water, pure copper
being used only for exceptional conditions.
What should be considered in selecting the proper metal
for the tubes?
Ans. Cost, life and thermal conductivity.
What is the latest practice with respect to tube diameter
and thickness?
Ans. The smallest outside diameter of tube usually is 5% in.
and the largest 1 in. Lengths run approximately from 4 to 22 ft.
The thickness varies from No. 16 to No. 20 B.w.g.
How are the tubes connected to the tube sheets?
Ans. 1, By stuffing boxes, or 2, by expanding.
What provision must be made?
Ans. Provision for expansion and contraction.
What packing is used in stuffing box joints?
Ans. Corset lacing impregnated with pure paraffin.
Water and Steam Circuits
How are condensers classified with respect to arrange-
ment of the water circuit?
Ans. 1, Single pass; 2, two pass, etc.
Condensers
703
How does the two-pass arrangement work?
Ans. The entry box is divided into two sections, the cir-
culating water is admitted to one of these sections, passes to
the second water box, there enters the remaining tubes and
returns to the other section of the entry water end..
How are more passes obtained?
Ans. By dividing the water box into more sections.
CROSS FLOW

BAFFLES
STEAM
CONDENSATE
Fig. 32.-Cross flow condenser. Evidently any number of lanes may be obtained
by baffling. The object of this arrangement is to completely control the steam
flow, thus preventing short circuiting. Moreover the accumulation of condensate
is discharged to the bottom of the condenser as formed in each alternate lane.
What are the various arrangements for steam flow?
Ans. 1, Single flow; 2, divided (dual) flow; 3, multi-flow;
4, cross flow.
}
Condenser Troubles
How would you take out a tube of a surface condenser?
704
Condensers
Ans. Remove the hand hole or man hole plate, whichever is
used, unloosen the ferrule and pull out the tube as far as you
can and plug the tube hole until such time as you can renew it.
It will be necessary to saw the tube in short pieces in getting
it out.
Condenser Operation
Name several ways that a vacuum may be lost.
Ans. The cooling water may be too hot, there may not be
sufficient water, some of the valves in the pump may be broken,

WATER
Protes
SASSIN
Sunn
BLIKË MBET
STEAM
j
WATER
WATER
AIR AND STEAM
Fig. 33.-Counter-flow condenser. In this arrangement the steam flows
parallel with the cooling water as indicated by the arrows. The baffle plates
caue the entering steam to flow in a direction parallel with the upper con-
densing tubes; when striking the end of the condenser body, the direction of
flow is reversed; this operation being repeated as often as there are baffle.
plates.
Condensers
705
the spray cone may have become plugged, clogged up or not
properly adjusted, the packing of the air pump may leak, may
be a leaky joint in the exhaust pipe, or there may be a com-
bination of these causes.
Why do they not run the steam through the tubes of a
surface condenser?

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Fig. 34.—Semi-dual bank surface condenser tube plate arrangement.
706
Condensers
Ans. On account of the packing.
If you were running a surface condenser and the vacuum
should be getting a little less than it was the week before
AIR
INLET
CONDENSATE PUMP
INLET
EXHAUST FROM TURBINE

AIR
INLET
CONDENSATE PUMP
INLET
RETURN FROM HEATERS
Fig. 35.-Typical dual bank surface condenser. The drawing shows the tube
arrangement and a de-aerating hot well chamber.
Condensers
707
until you could not get but 6 or 7 inches, what would
you think was the trouble?
BYPASS TO
REHEATING HOTWELL
Ans. That the water was by-passing instead of getting through
the tubes, and that the partition plate on the head had eaten
through and prevented the water passing through the tubes
and returning through the other half of bank of tubes. This
will occur around salt water.
CONDENSATE
OUTLET
AIR OFFTAKE

THROTTLE
PLATE
111 111 11 11 17
MULTI-PASS
AIR COOLER
#}_{1}}} //} }} }}
:
Fig. 36.-Condenser designed for double flow turbine where head room prevents
the use of a suitable steam dome. The steam from a modern double-flow
turbine exhausts in two more or less distinct paths. The condenser con-
sists of: two heart-shaped sections built side by side into a single shell.
Each section receives its steam from one of the two paths of the turbine exhaust.
A single air cooler serves both sections. The cooler is of the multi-pass type.
What is the result of leaky tubes?
Ans. They would lower the vacuum if leaking badly. The air
pump will have to handle the leakage water.
708
Condensers
How and when is the cylinder of an engine liable to
become flooded from a condenser?
Ans. When the throttle valve is closed and the condenser
stops.
Starting
There are two methods, depending upon whether the engine
have:
1. An independent air pump, or
2. A direct driven air pump.
In starting a jet condensing engine, care should be taken to
follow certain rules to prevent water entering the cylinder with
its attendant dangers.
What is the procedure in starting with an independent
air pump?
Ans. The injection valve is opened slightly and the air pump
started to its normal speed.
What is done when the vacuum is established as indi-
cated by the gauge?
Ans. The engine is warmed up in the normal manner and
started.
How is the vacuum controlled as the engine is brought
up to speed?
Condensers
709

ww
O
STEAM INLET
o
O
CONDENSATE
OUTLET
D
Fig. 37.-Exploded view of the type
condenser of fig. 40, showing how
condensers are divided into short
steam tight sections for the purpose of
controlling longitudinal distribution
of steam.

go
-11111smistETALDEHATI
08
•
AIR COOLER
selt)
Fig. 38.—Cross section of heart shaped condenser with graduated tube spacing
and multipass air cooler.
710
Condensers

MODERN LARGE CONDENSER
STEAM
BY-PASS
TO AIR COOLER
HOTWELL
VENT
REHEATING
AND DEAREATING
HOTWELL
UAAAAAAAAN.
O
KELAUALLY
CONDENSATE OUTLET
Figs. 39 and 40.-General arrangement of a large condenser with steam by passes and re-heating hot wetl
arranged for an external air cooler.
Ans. The injection valve is regulated so that the supply of cooling water will be
sufficient to condense the steam, otherwise the vacuum will fall.
What precaution should be taken when increasing the amount of cooling
water?

Condensers
711
Ans. Care should be taken that the air pump is running fast
enough to take care of all the water admitted.
How does the engineer know when the proper supply of
cooling water has been admitted?
Ans. He is guided by the vacuum gauge.
How is a high vacuum obtained?
Ans. The speed of the pump must be increased sufficiently
to handle the larger amount of cooling water required for the
higher vacuum.
Why should a steam by-pass be fitted to the exhaust at
the engine?
Ans. To facilitate the formation of a vacuum by blowing
out the air and priming the condenser with steam.
What is the procedure in starting an engine having a
direct connected air pump?
Ans. The cylinder is first warmed, and the engine set in
motion before opening the injection valve. This allows the
condenser to fill with steam which displaces the air. As soon as
the engine is in motion the injection valve is slightly opened,
the full supply of cooling water being not admitted until the
normal speed has been reached.
What is the reason for not admitting the full supply of
cooling water until the engine has been brought up to
speed?
Ans. The air pump being direct connected, the speed will
vary with that of the engine and while the engine is running
slowly, the pump displacement would not be sufficient for the
712
Condensers
full supply of cooling water. The condenser under these condi-
tions might flood and the water back up into the cylinder.
How do you start with a barometric condenser ?
Ans. Open exhaust pipe drain, warm engine and work the
water out of the cylinder; this will prime the exhaust pipe with
steam and cause the relief valve to open, allowing steam to
escape into the atmosphere.
Since a vacuum must be formed before the condenser will syphon
cooling water, open the starting or priming valve which admits water
to the discharge pipe, and in falling through it, draws out the air,
closing the relief valve and forming enough vacuum in the upper pipes
and condenser to draw the injection water up to the condenser.
The starting valve should now be closed and the water supply ad-
justed by the injection valve, being guided by the vacuum gauge.
Condenser Calculations
713
CHAPTER 37
Condenser Calculations
In the design of a condenser various calculations are neces
sary to properly proportion it to meet the requirements. These
include such calculations as those for:
1. The vacuum that can be obtained.
2. Quantity of cooling water required.
3. Cooling surface.
4. Size of removal pump.
5. Size of wet air pump.
6. Size of dry air pump.
7. Size of condensate pump.
Vacuum
Ins. Mercury
28
25.85
23.81
The Vacuum That Can Be Obtained.-By an inspection of
any steam table it will be seen that the pressure of the vapor
of water depends upon its temperature. That is, any enclosed
space partly filled with water and exhausted of air, will be
filled with the vapor of the water whose pressure depends upon
the temperature of the water. Thus consider the following
items from the steam tables:
Absolute Pressure
.946
2.
3.
Temperature
Fahrenheit
100°
126.15
141.52
714
Condenser Calculations
By inspection of the values for a 25.86 inch vacuum in the condenser the
condensate would have to be cooled to 126.15° Fahr. For either an increase
or lowering of the temperature of the condensate, the vacuum would decrease
or increase respectively. That is, if the temperature increase to 141.52°,
the vacuum would fall to 23.81 ins.; again if the condensate be cooled to
100° the vacuum would rise to 28°.
Ques. Could a 28° vacuum be obtained in a condenser with
the cooling water at 100°?
Ans. No.
Ques. Why?
Ans. This is impossible in practice as the final temperature
of the cooling water which is being heated by the incoming
steam would result in a temperature of the condensate higher
than that of the vacuum corresponding to that of the intial
temperature of the cooling water.
Evidently the final temperature of the cooling water must be somewhat
lower than the higher temperature of the steam. This terminal difference
as it is called is necessary because the heat transfer process is not 100%
efficient due to the time element.
Ques. To obtain a given vacuum what then is necessary?
Ans. The temperature of the cooling water should be some-
what lower than the temperature corresponding to the vacuum.
Quantity of Cooling Water Required.-The quantity of
cooling water required for the condensing process (per lb. of
steam condensed) depends upon numerous conditions as:
1. Required vacuum
2. Initial temperature of the cooling water.
ડ
66 66
3. Final
(6
Condenser Calculations
715
The quantity of cooling water required per lb. of steam to
be condensed may be expressed as follows:
Q
hi
(4
in which
Q = number of lbs. of cooling water to condense one lb.steam
H total heat above 32° in the steam
"6
ส
66
h
.66 ·66
¿
hf =
(6
"condensate
cooling water at final tem-
perature
cooling water at initialtem-
perature
Since Hh is the latent heat of steam (symbol L), the
formula may be written:
(C
((
66
"
H-h
hf-hi
(C ،،
،،
(6
66
(6
(6
"
L
hf - hi
Q
(2)
The value of Hh or L, being obtained direct from the
steam table making subtraction unnecessary.
L, for steam at 90°
hf, for cooling water at 90°
hi,
Substituting in formula (2)
Q:
Example.-How many pounds of cooling water is required to condense
one pound of steam of 90° temperature if the initial and final temperatures
of the cooling water be 60° and 90°?
From the steam table:
"60°
1041.2
58 - 28.08
=
=
1041.2 B.t.u.
58*
28.08
1041.2
29.92
(1)
"
¤
34.8 lbs.
That is under the conditions of the example it would require 34.8 lbs.
of cooling water to condense one lb. of steam. This is the theoretical quantity
716
Condenser Calculations
and is not possible in practice, as already pointed out, the final temperature
of the cooling water (hf) cannot be as high as the temperature of the steam
to be condensed.
Approximate Method of Calculating the Cooling Surface.-
For an approximation (very nearly, but not exactly) instead of
taking the total heats hi and hf of the cooling water, the tem-
peratures corresponding are used and formula (2) becomes,
Q
……. (3)
in which
T = final temperature of condensing water in deg. F.
initial
t =
66
<<
(6
(6
((
66 66
Substituting
L
T-t
Solving the same example with formula (3)
T = 90° Fahr.; t 60°
L
90 - 60
1041.2
30
Q
Comparing the two methods the results are 34.8 (real value)
and 34.7 (approximate value), the approximation being short by:
34.8 34.7
34.7 = .1 lb.
*
34.7 lbs.
Terminal Difference.-By definition, the terminal difference
is: The difference between the higher temperature of the steam
entering the condenser and the always somewhat lower final
temperature of the cooling water (that is, the injection water of a
jet condenser, or the circulating water of a surface condenser).
Ques. Why in practice is this terminal difference necessary?
Condenser Calculations
717
Ans. As before stated, in practice it is practically impossible
o render the heat transfer (from the steam to be condensed
.o the cooling water) 100% efficient because of the time element.
1
As can be realized the value of Q in the example just given is consider-
ably less than would obtain in practice.
Ques. What would be a reasonable terminal difference in
practice for ordinary conditions?
Ans. Say 10°.
Example.-How many pounds of cooling water are required to condense
one pound of steam 90° temperature if the initial temperature of the cooling
water be 60° and the terminal difference be 10°?
For a terminal difference of 10°, final temperature of cooling water 90°—
10° 80° L=1041.2 and T-t-80-60 = 20
From which, applying formula (3)
1041.2
20
Q
=
=
52.1 lbs. (approx.)
Applying formulu (2) hf=48.03 hi = 28.08
1041.2
Q
1041.2
48.03-28.08 19.95
V
52.2.
Ques. In modern practice what value is given to the final
temperature of the cooling water?
Ans. It is customary to make it 10° to 15° less than the
temperature of the steam to be condensed, ·
This factor is dependent upon the design of the condenser.
<<
Range of Design Vacuums.-According to Cameron with
various circulating water temperatures, the usual range for sur-
face condensers serving steam turbines is as follows: (For engine
service the vacuum is lower, usually 26 ins. or 26.5 ins.)
718
Condenser Calculations
DESIGN DATA
FOR CONDENSERS FOR STEAM TURBINES.

Inlet Water-T1.
50° F.
60
70
75
80
85
Design
Vacuum
28.5"
to 29.0"
28.25"
to 28.75"
28.0"
to 28.5"
28.0"
to 28.25"
27.75"
to 28 0"
27.5"
to 27 75"
Steam
Temp.-Ts
91.7° F
79.0
96.7
85.9
101.1
91.7
101.1
96.7
105.0
101.1
108.6
105.0
Temp. Diff.
TD₁ =(TS-T₁)
41.7° F.
29.0
36.7
25.9
31.1
21.7
26.1
21.7.
25.0
21.1
23.6
20 0
For the usual design or operating range, the capacity of any
condenser with a given temperature and quantity of circulating
water is directly proportional to the temperature difference
(TD).
With efficient design it is possible to handle 10 to 15 or 20 lbs. of steam
per sq. ft. of tube surface, depending on the desired vacuum and the quan-
tity of circulating water.
The quantity of circulating water required for a given steam load is de-
termined by the possible temperature rise (TR) which in turn is a fraction
of the temperature difference (TD) (approx. 40% to 60% for single pass
condensers, and 55% to 75% or 80% for two pass condensers, depending
principally on the tube size and tube length).
The relation between quantity of circulating water in gallons per min.
(Q) and TR irrespective of condenser size, type or design is as follows:
Q X 500 X TR
Steam condensed in lbs. per hr. X B.t.u. per lb.
=
The quantity of heat absorbed by the circulating water is generally as-
sumed as 950 B.t.u. per lb. for turbine service or 1,000 B..u. per lb. for
engine service. In special cases where the steam to be condensed is dry or
superheated it will be higher.—Cameron.
Condenser Calculations
719
06
70
POUNDS OF CONDENSING WATER PER POUND OF STEAM
60
50
40
08
30
40
40
TemperatuRE OF CONDENSING WATER IN DEGREES FAHRENHEIT
50
60
70
80
90
100
-BAROMETER 30™ MERCURY
70
275 ° VACUI
50
60
80
90
100
TEMPERATURE OF CONDENSING WATER IN DEGREES FAHRENHEIT
110

110
VACUUM
06
80
70
60
POUNDS OF CONDENSING WATER PER POUND OF STEAM
50
40
30
Fig. 1.—Curves indicating the ratio by weight of condensing water to steam.
for various vacuum and water temperatures.
The diagram fig. 1 (according to Wheeler) gives curves indi-
cating the ratio by weight of condensing water to steam for
various vacua and water temperatures.
To use the curves, add the terminal difference to the water temperature
and from the resulting temperature follow vertically to the intersection
with the diagonal vacuum curve.
At the point of intersection follow horizontally to the ratio indicated.
720
Condenser Calculations
For instance, with 15° F terminal difference, 70° F. water temperature,,
and 28 in. vacuum, the ratio is 59 lbs. of condensing water per pound of
steam.
Ques. In design, what should be noted about terminal
differences?
Ans. In general, the terminal difference is necessarily
greater with cold water than with hot, and necessarily greater
with lower absolute pressures than with higher.
It should be clearly understood that, once all the operating conditions
and the design of the condenser are fixed, then the actual terminal difference
obtained in practice is the result of physical laws and not of any arbitrary
decision to be made at will.
The Cooling Surface. According to Seaton, in practice with
the compound engines, brass condenser tubes 18 B.w.g.
(Stubs) thick, a condensation of 13 lbs. of steam per sq. ft.
per hour, with the cooling water at an initial temperature of
60° is considered fair work when the temperature of the feed
water is to be maintained at 120°.
In general practice the following holds good when the, tem-
perature of the sea water is about 60°.
Terminal pressure, lbs. abs.... 30 20 15 12% 10 8 .6
Sq.ft.cooling surface perI.H.P. 3, 2.5 2.25 2
1.8 1.6 1.5
For ships stationed in the tropics, the allowance should be
increased 20%; for ships stationed in cold climates 10% less
suffices (Seaton).
Cooling Surface for Water Works Condensers.-According to
Worthington the basis of heat transfer for water works con-
densers is 250 B.t.u. per sq. ft. per hour of mean temperature
difference.
The amount of cooling surface in square feet necessary to
Condenser Calculations
721
in which
condense a given amount of steam can be calculated from
the formula
WH
TU
F
=
F= sq. ft. cooling surface.
W weight (lbs.) of exhaust steam per hour.
H = total heat (B.t.u.) per lb. of exhaust steam.
T = mean temperature difference between the circulating
water and the exhaust steam.
U = rate of heat transfer in B.t.u. per 1 degree mean differ-
ence per sq. ft. of condensing surface per hour.
For ordinary calculations H is frequently assumed to be: 930 at 4 in.
absolute; 935 at 3 in. absolute; 940 at 2 in. absolute; 945 at 1 in. absolute.
In commercial calculations, a value of 950 B.t.u. is taken
as approximately correct for H. The value of T is found from
the formula
T = Ts
To + Ti
2
Where Ts is the temperature in steam space (assumed to correspond to
absolute pressure); T1, the temperature of circulating water at condenser
inlet in deg. F. and To, the temperature of circulating water at condenser
outlet in deg. F.
D
Hyp. Log.
The Grashof Formula.-According to Grashof a simple
arithmetic mean for the temperature difference is not correct,
but the following formula developed mathematically by
Grashof has been proven in practice to be very accurate, and
is used very extensively:
I?
Ꭲ
Ts - Ti
Ts – T₂
<<
722
Condenser Calculations
Where D. Mean temperature difference.
T₁
T2
Ts
= The lowest temperature of the fluid.
The highest temperature of the fluid.
The temperature of the gas or steam.
=
The transfer of heat through a unit of condenser tube area per unit of
mean temperature difference was early recognized as varying greatly under
different conditions. The most apparent variation being an increase with an
increase in the velocity of the cooling water.
Many experimenters have carried out exhaustive tests along this line to
determine the most practical value, but the results obtained vary greatly
owing to the fact that in practice there are encountered certain resistances,
which are in addition to the resistance offered by the metallic walls of the
tubes.
Ques. In practice with surface condensers what opposes
the transference of heat?
Ans. It is opposed by the resistance of the metallic walls
of the tubes, the resistance of the steam side of the tube due
to oil coating, or air entrained steam, and the resistance on the
water side of the tube due to the formation of scale.
Ques. What tends to prevent the formation of a coating
of oil on the condenser tubes?
Ans. A high steam velocity over the tubes, and there must
be no dead ends or stagnant places in the condenser.
Ques. How are surface condensers generally arranged to
avoid the resistance due to air entrained steam?
Ans. They are generally arranged so that the steam sweeps
the air ahead to the point of removal.
Ques. What should be noted with respect to the water
sides of the tubes?
Condenser Calculations
723
Ans. Considerable attention should be given to keeping
the tubes clean.
A high circulating water velocity will accomplish this to a marked degree
and is a more important reason for using small tubes, and several passes,
than is generally recognized.
Ques. What values are given to the co-efficient of heat
transmission or B.t.u. per sq. ft. per degree difference per hour?
Ans. It is generally taken in practice at 300 to 500, depending
upon the degree of vacuum, condenser design and velocity of
cooling water.
Velocity of Flow.-According to Whitham, the velocity of
flow of the circulating water through the tubes should be
between the limits 400 and 700 ft. per minute. As given by
Marks, the mimimum allowable spacing of tubes is as follows:
Outside diameter of tube, ins..... 5/8
Pitch of tubes, ins..
15/16
Number of tubes per sq. ft. of plate 189
3/4 7/8 1 1¼4
11/16
11/4 13% 15%
147
106 88 63
Jet Condenser Air Pump Calculations.-Now since the jet
condenser pump must handle everything that must be pumped
out of the condenser, in order to determine its size it is necessary
to calculate:
1. Amount of steam to be condensed.
2. Amount of water required to condense the steam.
3. Amount of air and other non-condensable vapors to be
removed from the condenser.
Each pound of injection water will absorb from the steam
to be condensed, a number of heat units approximately equal
to its rise in temperature in passing through the condenser,
1
724
Condenser Calculations
and the number of heat units to be taken out of each pound of
steam to cause condensation will be equal to its total heat
less the heat in the resulting condensate, that is,,
Quantity of injection water
or using the usual symbols,
t
denser.
T
denser.
=
t
in which
H = total heat in one pound of the steam.
h = heat in one pound of the condensate.
temperature at which the injection water enters con-
temperature at which the injection water leaves con-
in which
Q
W
=
Q'
Q
total heat of steam - heat in condensate
rise in temperature of injection water
Now, evidently, since the pump must handle both the injec-
tion water and the condensate, the total amount of water to be
handled is
total weight
condensate
(2
H-h
T
+ injection water X weight of steam
H
1 = 1)
+ T
.. (4)
X
total weight of water, entering condenser.
Weight of steam to be condensed in lbs.
W.......(5)
Water contains mechanically mixed with it 1/20 or 5% of
its volume of air at atmospheric pressure. If P = atmospheric
pressure and p = absolute pressure in condenser, then a cu.
ft. of water when it has entered the condenser is represented by
¡.95 of a cu. ft. of water and .05 × P÷p of a cu. ft. of air.
Condenser Calculations
725
Now if Q" = the total volume of water entering the condenser
per minute, T₁, temperature of the condenser, T2, temperature
of the cooling water (before entering condenser), then (accord-
ing to Seaton) .95 × Q" = volume of water in cu. ft. to be
pumped from condenser per min. and
the quantity of air
P
T₂+ 461°
X
p T₁ +461°
hence the total volume to be abstracted per minute that is,
P
total water and air .95 Q″ × .5 x
Þ
Q'
W
-(1.
Example.-A 100-horse power marine engine requires 30 lbs. of feed
water per horse power per hour. If the pressure in the jet condenser be 2
lbs. absolute (25.85 ins. vacuum), how much injection water is required
and what size pump if the initial temperature of the injection water be
60° and the final temperature 110°?
Total steam to be condensed per minute, or
Q"
=
.05 X
+
=
95% X 17.3 +5% X
100 X 30
30
Since from the steam table the total heat in lb. of steam at 2 lbs.
absolute pressure is 1,115 B.t.u., and the heat in the condensate 94 B.t.u.;
substituting in (5)
1 115 - 94
110 60
=
T₂ + 461°
2
T₁+461°
14.7
X
༡
50 lbs.
The weight of water at 110° being 61.89 lbs. per cu. ft., then its volume
at 110° or
50 = 1,071 lbs. approx.
1,071 61.89 17.3 cu. fɩ.
÷
95% of which is water and 5% air. Hence the total volume to be abstracted
from the condenser per minute is, taking the temperature of the condenser
at 120°:
=
. (6)
60 + 461
120 + 461
16.56 cu. ft.
726
Condenser Calculations
Now the usual practice is to use a pump having a displacement of twice
the volume to be pumped, that is, to let the pump fill half full of water,
the remainder being occupied by the expanded air. Accordingly, given
displacement is
·
16.56× 2
33.12 cu. ft. per minute
The normal piston speed should be about 100 ft. per minute. hence
area of piston 33.12 ÷ 100 .331 sq. ft., or .331 × 144 = 47.7 sq. ins.
ސ
=
diam. of piston corresponding
=
****
area
V.7854
and the length of stroke will depend on the number of strokes per minute,
which, for say 60 strokes per minute, is
33.1260
.552 ft. or .552 X 12 = 6.62, say 7 ins.
Ques. For accuracy what kind of heats should be used in
condenser calculations?
Ans. Total heats instead of sensible heats or temperatures.
47.7
.7854
Heat in 1 lb. water at 70° Fahr
Heat to raise temperature of 1 lb.
of water 10° between 70° and 80°)
}
8 ins. approx.
It should be understood that standard B.t.u. used is mean B.l.u. which
1
is defined as: part of the heat required to raise the temperature of one pound
180
of water from 32° to 212°F. In fact the heat required to raise the temperaturę
of water 1° depends upon the temperature. Thus from the steam table:
Heat in 1 lb. water at 80° Fahr....
48.03 B.t.u.
38.06
9.97 B.t.u.
••
This is the actual heat which is a little different from the result obtained
by subtracting temperatures, that is 9.97 B.t.u. and not 80-70 or 10 Bt.u.
Surface Condenser Wet Air Pump.—In a surface condenser
the pump has to handle only the condensate and air, the cooling
or "circulating" water being pumped by the circulating pump.
As compared with a jet condenser, the pump handles a much
Condenser Calculations
727
smaller quantity of water and a relatively large volume of air.
The latter item is important because the air volume to be dis-
placed is much larger than the water volume. The air entering
by leakage is uncertain and may be 3 or more times as much as
was liberated by the water.
་
Since the pressure in the l.p. cylinder of the engine is most of
the time below atmospheric pressure, considerable air may leak
in through the stuffing boxes unless they be tight.
The practice of some pump companies is to give the air pump a displace-
ment equal to 20 times the volume of the condensate, if it be a horizontal
double acting pump, and 12 times if vertical single acting.
According to Whitham the usual practice is to make the air pump for a
surface condenser one half the capacity of one required for a jet condenser.
This will enable the surface condenser to be used as a jet condenser in case
of emergency. The air pump should always be placed below the condenser
for best results (though this is not always possible with keel condensers),
and the delivery valves should be water sealed.
Ques. Why are the proportions 20 and 12 given for hori-
zontal and vertical pumps respectively?
Ans. The vertical pump is more efficient than the horizontal
pump.
Formula for Wet Air Pumps.-According to Worthington
it is considered good practice to make the capacity of the wet
air pump for a surface condenser equal to 20 or 30 times.
the pounds of steam condensed per unit of time. The following
formula may serve as a guide to the multiple to use:
5(54+1)
DV = S 1.5
in which
DV = Displacement of air pump in lbs. per hour
728
Condenser Calculations
Percentage Increase in Output.
S
Pa
54
Pa
140
120
100
80
60
40
20
=
=
0
22
Pounds of steam per hour
Absolute pressure in inches of mercury
Amount of vapor arising from the steam.

23
24
25
Vacuum in inches
26
27
28
29
(Barometer 30').
Fig. 2.-Economy at high vacuum. The curve, according to Manistee
shows the output from an exhaust steam turbine as the vacuum increases
from 22" to 29" from which will be seen that at 28½" the increase in output
is over 100 per cent of the power of the turbine with only 22" of vacuum
and that the rate of increase rises rapidly as the vacuum approaches the
higher limits. Thus, the addition of 1" of vacuum from 23" to 24" adds
10 per cent, but addition of 1" vacuum from 28" to 29" adds 40 per cent.
Condenser Calculations
729
Dry Air Pumps. For high vacuum dry air pumps are
necessary. The displacement of the dry air pump is, according
to Worthington,
54
DV = × S, approximately.
Pa

Condensate Pump.-This pump handles the condensate and
nothing else and its displacement per minute is accordingly
equal to the pounds of condensate per minute, that is
lbs. of steam per hour
Displacement
lbs. per gallon × 60
aking 8.33 lbs. as approximate weight of one gallon
Displacement per minute in gallons
U
lbs. of steam per hour
8.33 × 60
lbs. of steam per hour
500
. 2.—Text continued.
the power of the turbine on the same percentage scale for economy
igh vacuum condensing plants therefore become essential. It must be bome
mind that the volume occupied by exhaust steam increases rapidly as the
uum approaches the barometer reading, that is, the volume varies inversely
he absolute pressure. For instanc e volume is doubled by an increase
cuum from 28" to 29" with a 30 ometer. For this reason the Condenser
m for reciprocating engines is y limited to 26″ or 27″ because the
st ports of a reciprocating
re not generally large enough to
the

730
Condenser Calculations
The condensate of steam exhausting into a 25.8 inch vacuum
will have a temperature of 126° Fahr. At this temperature
one cu. ft. of the condensate weighs 61.61 lbs. and one cu. in.
weighs
61.61 X
1728
.0357 lb.

Example.-An engine exhausts 1500 lbs. of steam per hour. With con-
densate at a temperature of 126° corresponding to a weight of 0.357 lb.
cu. in., find displacement per minute of condensate pump.
per
Volume of condensate to be handled per minute
70 cu. ing.
1500
0.357 X 60
A condensate pump used in connection with a surface condenser (with
dry air pump) according to one authority is generally given a displacemen
of 2 to 3 times the volume of the condensate.

Steam Jet Air Ejectors
731
CHAPTER 38
Steam Jet Air Ejectors
What is a steam jet air ejector?
Ans. A device for air removal from closed vessels in which
the operating pressure is less than atmospheric and whose basic
principle of operation is similar to the feed water injector.
How does the ejector work?
Ans. It operates by means of the entrainment action pro-
cured by a jet of high velocity steam.
What are the essential parts?
Ans. A vacuum chamber in which is an expansion steam
nozzle connecting with a venturi shaped tail piece.
How does the device work?
Ans. Steam at high velocity passing through the expansion
nozzle entrains any gases (air, steam or others) adjacent to it
and carries them through to the diffuser (tail piece). Part of
the momentum of the steam is transferred to the incoming air
or vapors with a resultant velocity high enough to discharge
the mixture at the designed discharge pressure.
How is the mixing and compression of the gases accom-
plished?
732
Steam Jet Air Ejectors
Ans. This takes place in the diffuser.
This diffuser (also called a compression tube or tail piece) consists
essentially of a converging section, followed by a minimum section
(called the diffuser throat) and then by the diverging section.
In the latter, velocity energy is converted back into the pressure
energy required to discharge the steam-air (or gas) mixture against
the pressure existing at the outlet of the element.
What are the applications of ejectors?
Ans. Steam jet ejectors are generally used to remove air,
gases or vapors, from systems or vessels where the operating
pressure required is less than atmospheric pressure (14.7 lbs.
absolute at sea level). Occasionally however, such ejectors are
used to handle steam or gases at inlet pressures above atmos-
pheric and to discharge them at somewhat higher exhaust
pressures.
What is a thermo-compressor or booster ejector?
Ans. One designed to handle steam instead of other gases.
How are ejectors classed?
Ans. With respect to the number of stages, as one, two,
three stage, etc.
What are the applications of the single stage arrange-
ment?
Ans. The single stage ejector, in which the gas is compressed
in one stage, is suitable for vacuums up to 26.5 ins. of mercury.
Why is the single stage not used for higher vacuums?
Ans. While single stage ejectors can be built for higher vacua,
the steam consumption becomes excessive as compared with
multi-stage units.
*
Steam Jet Air Ejectors
733

Fig. 1.-Single stage ejector This type has a limited ratio of compression.

A
Fig. 2.—Single stage ejector with after condenser A. A single-stage ejector
discharging into an after-condenser which condenses the operating steam
(and vapor if any) and allows the non-condensibles to escape to atmosphere.
After-condensers can be applied to the discharge of any ejector, whether
single or multi-stage or multiple element

010
P
Α'
Fig. 3.-Single stage ejector with pre-cooler P. When the mixture handled by the
elector_contains vapors which can be condensed at operating vacuum and
available water temperature; a pre-cooler can be used ahead of the ejector
to reduce the weight of the mixture handled by the ejector. It reduces the size
and steam consumption of the ejector In these ejector illustrations Aʼ, indi-
cate: optional, either surface or barometric type condenser.
734
Steam Jet Air Ejectors
What is the application of the two-stage ejector?
Ans. They are suitable for vacua of 26.5 to 29.3 ins.
Of what does the two-stage ejector consist?
Ans. Two ejectors connected in series.
What is used with a two-stage ejector?
Ans. An inter-condenser is placed between stages.
Describe a three-stage ejector.
Ans. It consists of three ejectors connected in series with
inter-condenser.
What is its application?
Ans. For vacuums from 29.3 to 29.9 ins.
Ejector Operation
A. SINGLE-STAGE EJECTORS WITH OR WITHOUT
AFTER CONDENSER
Starting Up Procedure
1. Open discharge valve (or valves*).
2. If an after condenser be provided, next turn on water supply valve.
3. Open steam valve (or valves*) admitting steam from a supply
line at the proper pressure.
4. Open steam valve (or valves*) admitting steam from a supply line
at the proper pressure.
5. Open air inlet valve (or valves*).
Steam Jet Air Ejectors
735
As soon as the full steam pressure is supplied in the steam
chamber the ejector will start operating. The vacuum will be
gradually increased as the air is removed from the system and
after a short interval of time the normal operating vacuum will
be obtained.
Shutting Down Procedure
1. Close inlet valve (or valves*).
2. Close steam valve (or valves*).
3. Close water supply valve.
4. Close discharge valve (or valves*).
* NOTE.-This applies to multiple element types of ejectors.
B. TWO-STAGE EJECTORS (SINGLE ELEMENT)
Starting Up Procedure
1. Open air exhaust valve at discharge of secondary element or after
condenser.
2. Open air inlet valve at inlet of primary element.
3. Open valve in inter condenser drain loop.
4. Open drain valve in after condenser drain line (if the inter condenser
and after condenser be of the surface type).
5. Start water circulating through the inter and after condensers.
6. See that both steam valves are closed.
7. Open main steam supply valve admitting steam at the proper
pressure from steam lines.
8. Open steam valve to secondary element.
As soon as the full steam pressure is supplied to the steam nozzles
the ejector will start operating. An interval of time should then be al-
lowed to build up the vacuum to approximately 16 in. to 20 in. Then
the primary element should be put in service as follows:
9. Open the steam valve to the primary element.
1
736
Steam Jet Air Ejectors

110
A
Fig. 4.—Two stage non-condensing ejector. For greater ratios of compression
(higher vacuum) than are attainable with a single ejector, two ejector elements
can be operated in series or stages. In its simplest form the primary discharges
directly into the secondary Such a two-stage non-condensing ejector is
necessarily rather uneconomical in steam consumption because the secondary
has to handle all the primary operating steam in addition to the non-con-
densibles and vapors.
201

P
A
Fig. 5.-Two stage condensing ejector. Usually an intercondenser, I is inserted
between stages to condense the operating steam used by the preceding stage,
thereby reducing the load, size und steam consumption of the following stage.
DY

Α
t=.
S
Fig. 6. Two stage condensing ejector with pre-cooler. When a portion of the
vapors entering the primary of a two-stage ejector can be condensed at opera-
ting vacuum and available water temperature, a pre-cooler, P can be applied
chead of the primary to reduce the size and steam consumption of the ejector.
Steam Jet Air Ejectors
737
After another short interval of time, the normal operating vacuum
will be obtained.
10. If the ejector be provided with a jet inter condenser, the water
supply should be turned on before the steam is admitted to the primary
element. The water quantity should be regulated to provide sufficient
cooling water, but care should be exercised to limit the flow to prevent
flooding the jet inter condenser.
The procedure just outlined is for starting up ejectors on a complete
system, bringing up the vacuum from atmospheric pressure. If a system
should be provided with two steam jet air ejectors and it be desired
to put a second ejector into service while the other ejector is in opera-
tion, all operations except Nos. 2 and 3 should be performed in their
regular order. After full vacuum is established at the inlet of the
primary element on the ejector, that is to be placed in service, then
operations Nos. 3 and 2 should be carried out in this order.
Shutting Down Procedure
1. Close primary air inlet valve.
2. Close steam valve to primary.
3. Close steam valve to secondary.
4. Close main steam supply valve.
5. Close condensing water supply valve to inter and after condensers.
B. TWO-STAGE EJECTORS (TWIN OR TRIPLE
ELEMENT WITH ISOLATING VALVES)
Starting Up Procedure
1. Open valve in air discharge line from after condenser.
2. Open secondary element discharge valves.
3. Open secondary element inlet valves.
4. Open primary element discharge valves.
5. Open primary element inlet valves.
6. Open valve in inter condenser drain loop line.
738
Steam Jet Air Ejectors
7. Open valve in after condenser drain line.
8. Start circulation of water through surface type inter and after
condenser.
9. See that the steam valves to all elements are tightly closed.
10. Open the main steam supply valve admitting steam at the proper
pressure to the ejector.
11. Open steam valves to secondary elements.
As soon as the full steam pressure is supplied in the steam chambers,
the pump will start functioning. An interval of time should be allowed
to build up the vacuum to approximately 16 in. or 20 in. Then the
primary elements should be put into service as follows:
12. Open the steam valves to the primary elements.
After another interval of time the normal operating vacuum will be
obtained.
It is customary to use all sets of elements for establishing
full vacuum on the system in the shortest period of time.
If the air leakage to the system be at a minimum, then the desired
vacuum can be maintained by operating with only one set of elements
(one primary and one secondary).
When a condenser is furnished with a priming ejector, it is
started up first and allowed to operate until the condenser
vacuum reaches 25 to 26 ins.
The ejector is then shut down by closing air inlet and steam supply
valves in the order named.
Where an ejector is equipped with raw water auxiliary cooling
section, the water valve should be opened when ejector is
started up.
The same instruction applies to re-circulation of condensate. Unless
the steam load be very light, the raw water or re-circulation valve can
be closed after full vacuum is reached.
Steam Jet Air Ejectors
739

VVIE
Fig. 7.-Three stage non-condensing ejector. For still higher vacuums (lower
inlet pressures) than are economically attainable with a two-stage ejector,
three ejector elements can be operated in series. This is the simplest but least
economical three-stage ejector. Steam consumption is relatively high because
operating steam is not condensed between stages.
1/2010

A
Fig. 8.-Three stage ejector with non-condensing first stage When cooling
water temperatures are too high to permit condensing out operating steam
between booster and second stages of a three-stage ejector; the booster
stage operates non-condensing and discharges directly into a standard two-
stage condensing unit.
208020
Fig. 9.-Three stage condensing ejector. When operating conditions and
cooling water temperature permit intercondensers' between all stages of a
three-stage ejector, the unit is more economical in steam consumption than
either of the arrangements shown in figs. 7 and 8.

740
Steam Jet Air Ejectors
Shutting Down Procedure
1. Close the inlet valve of element to be shut down.
2. Close steam valve to same element.
3. Close the discharge valve of same element.
When shutting down one set of elements only, it is recommended
that the primary element be shut off first and then the corresponding
secondary element.
In order to maintain the normal vacuum it is necessary to have one
primary and the secondary element in service together.
It is not possible to obtain high vacuum with two secondaries
only without any primaries, nor with two primaries alone and
no secondaries.
If it be desired to put any additional elements into service,
the shutting down procedure just outlined should be reversed.
To Shut Down a Complete Ejector
1. Close primary inlet valves.
2. Shut off main steam supply.
3. Shut off water supply to inter and after condenser.
Operation of the three-stage ejector is similar to that of the two-stage
unit with the additional operation of the isolating and steam valves of
its primary stage.
Name six possible causes for faulty operation of an air
ejector.
Ans. 1, Insufficient cooling water; 2, steam nozzles plugged
with scale; 3, water flooding inter condenser due to faulty
drainage; 4, low steam pressure; 5, high back pressure at dis-
charge of ejector; 6, loss of water seal in inter condenser drain
loop.
Steam Jet Air Ejectors
741
How do you check for insufficient supply of cooling
water?
Ans. By observing the temperature of the water entering
and leaving the air ejector. If the temperature rise in the ejector
be not excessive, the cooling water supply is adequate and the
trouble is elsewhere.
What do you do if a scale deposit form in the throats of
the steam nozzles?


Fiy. 10.-Multiple element ejectors. For greater flexibility in operation, the
ejector elements making up single- or multiple-stage ejectors can be paralleled
"Such paralleling is known as multiple elements (i.e. single-element, twin-
element triple-element etc.)
Ans. It should be removed with drills of the same diameter
as those with which the nozzles were originally drilled.
How do you check for flooding of the inter condenser?
Ans. By feeling the temperature of the inter condenser shell.
What causes low pressure steam?
Ans. Clogging of the steam strainers or orifice plates with
pipe scale or sediment, improper operation of the regulating
valve, or low boiler pressure.
742
Steam Jet Air Ejectors

AFTERCONDENSER
20 19 21 18 3
16
3
175
18 3
INTERMEDIATE CONDENSER
ARRANGEMENT OF AIR EJECTORS
WITH SURFACE TYPE INTERMEDI-
ATE AND AFTER CONDENSERS
23
M5]
Fig. 11.-Typical piping ar-
rangement of a large surface
condenser and auxiliaries
The parts are given on the
opposite page
22
TO ATMOSPHERE
8 26
231
27. 10
-10
9 11 13
223
25
24
15
12
1
2
Suda
100
14
CONDENSATE PUMP
5 2
TAWAN
TURBINE EXHAUST
SURFACE CONDENSER
28
~.
IN
3
-29
CONDENSATE
WELL
CIRCULAT-
ING PUMP
Steam Jet Air Ejectors
743
LIST OF PARTS
(FOR FIG. 11)
1. Atmospheric relief valve
2. Expansion joint
3. Gate valve
4. Circulating water discharge from main condenser
5. Condensate from condenser to condensate pump
6. Check valve
7. Condensate from condensate pump to intermediate and affør
condenser
8. Condensate from intermediate and after condensers
9. Condensate line to heaters
10. Condensate recirculating line to main condenser
11. Condensate control for recirculating line
12. Vent from control valve float chamber
13. Condensate line to control valve float chamber
14. Vent from condensate pump to main condenser
15. Air removal line from main condenser to first stage ejectors
16. Air ejectors (first stage)
17. Air ejectors (second stage)
18. Stop valve (steam)
19. Throttle valve (steam)
20. Steam Strainer
21. Steam pressure gauge
22. Intermediate condenser condensate drain loop
23. After condenser condensate drain dripping
24. After condenser drainer
25. After condenser drainer float chamber piping
26. After condenser drainer float chamber vent
27. 'Intermediate and after condensate return to main condenser
28. Main condenser support springs.
29. Main condenser spring support,
:
744
Steam Jet Air Ejectors
T
What causes high back pressure at the discharge of the
ejector and what do you do?
Ans. This sometimes occurs where the pump discharges into
a common exhaust system with other equipment. If this happen
it will be necessary to provide an independent discharge from
the ejector to atmosphere.
How about loss of water seal in the drain loop?
Ans. This takes place occasionally in installations where the
vacuum in the system is subject to sudden fluctuations.
What should be placed on the inter condenser drain
loop to show whether the valve is properly sealed when
the ejector is in normal service?
Ans. A gauge glass.
CA
Where is this glass located and what is the indication?
Ans. As near the bottom of the drain loop as possible, and
if the water be visible anywhere in the glass, the loop is properly
sealed.
What are the indications that the drain loop has become
unsealed?
Ans. This is indicated if no water be visible or if it surge
violently in the glass.
What is the cause of this?
Ans. When this happens some of the air, which has been
removed from the main condenser by the primary element, is
re-circulated and flows back through the drain loop to the
main condenser, thereby reducing the vacuun.
How do you re-establish the seal in the drain loop?

Steam Jet Air Ejectors
745
PERATING
nih 9d3 STEAM
nath sd mi
ami to boro
end 1911A q
svley sil
EVAFOR
INCE
sit to univ
BOOSTER
fyloid be
skladem ad offens
220000001202 2
ninogo bol
BOOSTER
CONDENSER
HAILTRE
OPERATING
STEAM
HUT WELL
rod blog, ad edit29(
9dTenA
Food betiuper
nings retw
To ad bisode
fett
11
INLET
OPERATING
STEAM
COR
ANTERCONDENSER
SAMSTAGE
EJECTOR
TAIL SIRE
BOFT MIN
AIR AND STEAM
SCHARGE TO
ATMOSPHERE
iamo ni
2ND STAGE Oult of sub
EUFOTOR 916190 of
bons Ju ti
olen/
anil qout
COOLING
WATER
OUTLET
onTanA
s bas 19trw
Fig. 12.-Flow diagram of three stage ejector with counter current barometric
booster condenser and inter-condenser.
746
Steam Jet Air Ejectors
1
!
Ans. Close the valve provided for this purpose in the drain
loop line-usually located near the condenser.
Describe how the valve should be operated?
Ans. The valve must be closed for the short period of time
required to form sufficient condensate to fill the loop. After the
water again shows at the top of the gauge glass, the valve
should be opened very gradually.
What will happen if the valve be opened too quickly?
Ans. The difference in pressure will cause surging of the
water and again unseal the loop.
In certain cases, some drain loops have a tendency to be unstable
due to fluctuations in condenser vacuum. In instances, it is customary
to operate with the valve in the drain loop line partly throttled, opening
it just enough to pass the condensate at all times.
Cooling Ponds and Towers
747
CHAPTER 39
Cooling Ponds and
Cooling Towers
1. Cooling Ponds
What is a cooling pond?
Ans. A shallow reservoir having a large surface area for re-
moving heat from cooling water used to condense steam in
condensers.
What is the adaptability of cooling ponds?
Ans. In sparsely settled districts where land is cheap and
when cooling water is scarce, or expensive or where it is rendered
unfit for use in condensers by pollution from waste products of
manufacturers, cooling ponds are used to advantage as the
cooling water may be used over and over again.
What loss takes place with cooling ponds and how made
up?
Ans. There is a small loss of water by evaporation, being
made up from an outside source.
748
Cooling Ponds and Towers
How much cooling water is used where no means is pro-
vided for re-cooling?
Ans. From approximately 25 to 35 times the feed water de-
pending upon conditions.
The following examples will give an idea of the very large
amount of water required where no means is provided to cool it
so that it can be used again.

POWER HOUSE
HOT WATER DISCHARGE
TROUGH
- NATURAL FLOW POND
INTAKE

Figs. 1 and 2.-Non-directed flow natural cooling pond suitable for long and
narrow lots.
Example.-A 100 horse power engine runs on 30 lbs. of feed water
per hour per horse power. If the cooling water for the condenser be 27
times the feed water how many gallons of cooling water are required
per 10 hour day.
total feed water
=30X100X10=30,000 lbs. per day.
30,000 ×27
813
-
= 97200 gallons.
total cooling water
which at the usual city rates for water would be prohibitive, or at least
the expense would largely offset the saving by condensing.
Cooling Ponds and Towers
749
POWER
HOUSE
Name a few types of cooling ponds.
Ans. 1, Natural; 2, spray, a, single deck, b, double deck;
3, natural flow; 4, directed flow; 5, shallow; 6, deep; 7, open;
8, Louvre fence.

INTAKE
DISCHARGE
A
DIRECTED
FLOW
POND

B
T
Figs. 3 and 4.-Directed flow natural cooling pond. In operation, the hot
water enters the middle channel at A, and on reaching the far end divides into
two currents, being directed by the baffle walls so as to traverse the pond
several times before uniting at the intake point B.
Upon what does the type to be used depend?
Ans. Upon the ground available.
What is a natural pond?
Ans. A natural flow pond having no baffle walls or spray
nozzle.
750
Cooling Ponds and Towers
How is the cooling accomplished?
Ans. By: 1, Radiation; 2, convection, and 3, evaporation.
What effect has the weather on the cooling?
Ans. In cold weather cooling is obtained mostly by radiation
and convection; in warm weather by evaporation.
How much cooling surface is required?
INTAKE
SINGLE DECK
HOT WATER DISCHARGE

÷
SPRAY NOZZLES
Fig. 5.—Single deck spray pond.
Ans. According to Fernald and Orvok under the conditions
prevailing in Northeastern United States a natural cooling pond
surface of 250 sq. ft. is sufficient to cool the condensing water
required for a boiler horse power at 26 inch vacuum.
Describe a spray pond.
Ans. A pond of this type is provided with spray apparatus
so that the hot water from the condenser is sprayed over the
surface of the pond.
Cooling Ponds and Towers
751
What is the action of spraying?
Ans. The hot water passing through a multiplicity of jets
passes through the air in a finely divided state, its surface area
is greatly increased, this intensifying the cooling by evaporation.
Accordingly for a given cooling capacity, the size of the pond is
much less than that of a natural pond.
INLET-
How is the loss of water prevented by the spray being car-
ried away by the air currents?
DOUBLE DECK
HOT WATER DISCHARGE

UPPER SPRAY NOZZLES
x L L L L
LOWER SPRAY NOZZLES
Fig. 6.-Double deck spray pond.
Ans. By extending the sides of the pond or by providing an
enclosing fence.
What is the usual range of cooling?
Ans. 20° to 40° Fahr. depending upon conditions.
How much cooling surface is required for a spray pond?
Ans. About 4 sq. ft. of surface are required for a boiler horse
power to condense steam at 26 inch vacuum.
752
Cooling Ponds and Towers
What is a double deck spray pond?
Ans. One having spray nozzles arranged at different eleva-
tions.
According to the Spray Engineering Co. careful tests made by dis-
interested engineers, extending over a period of several weeks, show
that the average amount of heat dissipated from the surface of a
natural cooling pond with directed flow is 3.5 B.t.u. per sq. ft. per hour
per one degree.


.
B!!!
18
Fig. 7.-Turbine type spray nozzle, showing removable turbine center for im-
parting the rotary motion to the liquid.
Fig. 8.-Turbine type spray nozzle with center jet nozzle. In operation, some
of the water to be sprayed passes through the outer turbinated passages and
is gradually given a rapid rotating motion. The non-rotary straight central jet
strikes this rotating mass of water at a point just below the orifice in the space
called the mixing chamber, resulting in a mixing or blending of the rotary and
non-rotary jets and compelling issuance of the water from the orifice in a fine
flaring spray.
Cooling Ponds and Towers
753
Is feed water taken from the pond?
Ans. No.
Where and why?
Ans. It is taken from the discharge pipe line between the
condenser and the pond in order to save heat.
What is the action with a spray cooling system when
there is no breeze?
LOUVRE FENCE

BALLBROO
rrrr
1896 Primumfumukansiemenerusfitentiam munjungan pis gumy a BESTA
SPRAY CAUGHT BY FENCE
COOLING POND
immine
Fig. 9.-Louvre fence for preventing loss of spray water by air currents.
Ans. An effective current of air is created in an upward
direction around each nozzle due to the movement of the spray
as well as to the heating effect which the spray has on the air
which comes in contact with the water.
What is the result of such action?
Ans. The warm moist air produced is rapidly carried away
and replaced by cool dry air brought in from all sides over the
surface of the pond.
754
Cooling Ponds and Towers
When are spray ponds most efficient?
Ans. In extremely hot weather when the humidity is high.
Since a pond 6 inches deep will usually give as good results
as one 10 feet deep, why are deep ponds sometimes pro-
vided?
Ans. To provide water storage for fire protection.

MSN 192553)
A VALLACEVTS
FOR THE
Fig. 10.-Cooling pond with spray system on roof.
❤
PAT2rZo
AIR}:
Cooling Ponds and Towers
755
What is the water loss in a spray system from evaporation
and drift?
Ans. The average loss from these causes is from 1 to 2 per
cent of the amount of water sprayed.

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TRAVERSE FEEDER
DISTRIBUTION TROUGHS
Fig. 11.-Detail showing distribution deck consisting of transverse feeder and
distribution troughs.
2. Cooling Towers
What is a cooling tower?
Ans. An apparatus designed to remove from condensing
water as much heat as can possibly be abstracted per unit of
space occupied by the apparatus.
Where are they used?
756
Cooling Ponds and Towers
Ans. In large cities where ground is extremely valuable.
The expense of buying land is avoided by placing the cooling appara-
tus on the roof.
Describethe construction of a cooling tower.

TRAVERSE FEEDER
•
DISTRIBUTORS
ཚན
Fig. 12.-Typical distribution deck.
Ans. Essentially it consists of a tower or stack from the top
of which the heated circulating water is sprayed over a cellular
construction of brushwood, earthenware pipes, wire mats,
wooden checker work or other baffles designed to expose the
water to the cooling action of the atmosphere while in a film
or fine rain state.
Cooling Ponds and Towers
757
How is the process assisted?
Ans. By the evaporation of part of its bulk.
How are assisting counter currents provided?
Ans. By side ventilation, natural draught enclosing the tower
and using it as a chimney, or by a fan blast (forced draught).
TRANSVERSE FEEDER
BRUSHWOOD
PUMP
DISTRIBUTION
DECK
H
DISTRIBUTORS
Fig. 13.-Open natural draught brushwood cooling tower. This is about the
simplest form of tower, being of very ordinary construction.
To what is the cooling effect. due?
Ans. 1. Radiation from the sides of the tower; 2, contact of
the water with the cooler air; 3, evaporation of the water.
▼

758
Cooling Ponds and Towers
P
}
4
Example.—A certain condenser requires 100 lbs. of water per minute,
which is discharged at 110°, and it is desired to cool it to 70° Fahr.
What will be the evaporation in the cooling tower?
The total heat to be abstracted from the water per minute is
100 X(110-70)=4,000 B.t.u.
Now, if say 20 per cent of the cooling effect be due to radiation and
LOUVRED SIDES

SUNUTMADI CONTA
MIUITANI
L
uwig
MARIONARIE
+421
ATTGRAINATU
Fig. 14.-Louvered sides or slatted enclosure to prevent loss of water due to
lateral air currents.
convection or contact of the water with the cooler air, then heat to be
removed by evaporation is
4,000 (100%-20%) =3,200 B.t.u.
At 110° the latent heat of evaporation is 1,030 B.t.u., hence
evaporation =3,200÷1,030 = 3.1 lbs. per minute*
Cooling Ponds and Towers
759
CHIMNEY
Each pound of free air absorbs 2.375 B.t.u. while its tempera-
ture is raised 10 degrees. Thus the temperature difference be-
tween the water and the entering air limits the heat transfer
by convection. For every 1,000 B.t.u. of heat transferred in this
manner, 422 pounds or about 5,600 cubic feet, of air must be

WATER DISTRIBUTION
AIR INLET
COLD WATER
WATER INLET
COOLING STACKS
AIR INLET
OUTLET PIPE
Fig. 15.—Induced draught cooling tower with zigzag cooling stacks.
brought in contact with the water and warmed 10 degrees, or
2,800 cubic feet 20 degrees, etc.
The same volume of air will absorb an additional and much
larger quantity of heat through evaporation. Each pound of air
760
Cooling Ponds and Towers
3/
LBS
LIGHT AIR
STACK
INDUCED DRAUGHT

16 EXPANSIONS
INITIALT
VOLUME
1
16
8 EXPANSIONS
ㅎ
​-100
LB
16
LB
I LB
LBS
HOT
WARM
a
COOL
C
B
A
HEAVY AIR
a
3 LBS
b
I LB
I LB
ILB
3 LBS
Fig. 16.-Diagrams to accompany text explaining principle of induced draught.
Cooling Ponds and Towers
761
entering the cooling tower at 72° with 70 per cent saturation,
and leaving saturated at 102° will absorb only 7.2 B.t.u. by its
rise in temperature, but 28.7 B.t.u. by the water it evaporates.

FORCED DRAUGHT
NATURAL DRAUGHT
DOOR OPEN
DOOR
CLOSED
}
WORM & WORM WHEEL
FOR OPERATING DOOR
ドル
​Fig. 17.-Induced natural draught tower as installed at Waco, Texas.
*NOTE.-Bearing in mind that the latent heat absorbed by the cooling water.
while condensing one pound of steam in the condenser, must equal the latent
heat extracted in the tower when evaporating one pound of water, the quantity
of water evaporated will equal the quantity condensed, less the percentage of
heat removed by convection and direct radiation. In other words, the cooling
tower has to evaporate a quantity of water equaling 75 to 85 per cent of the
weight of steam (corresponding to the feed water) passing through the turbine
or engine. This loss must be replaced by a fresh supply.
5 13
***
762
Cooling Ponds and Towers
!
How much heat does the air absorb?
Ans. Each pound of free air absorbs .2375 B.t.u. while its
temperature is raised 1° Fahr.; that is, 2.375 B.t.u. per increase
of 10°.
What is this called?
Ans. The specific heat of air at constant pressure.
FAN
DRIVE
PULLEY
INCOMING AIR
*
FORCED DRAUGHT

ENCLOSED
TOWER
Fig. 18.-Elementary forced draught cooling tower showing fan.
How about the location of cooling towers?
Ans. They may be located either at the ground level or on a
*NOTE.-For explanation at length on the specific heat of air both at con-
stant pressure and at constant volume, see Pumps, Hydraulics and Air Com-
pressors by the author, published by Theo. Audel & Co.
B
Cooling Ponds and Towers
763
roof or other elevated structure, depending upon the space
available and other local conditions.
What are the advantages of ground level location?
Ans. 1, Simplicity of foundation and reservoir construction;
2, shorter pipe lines, resulting in lower first and operating costs,
and 3, localization of possible spray during high winds.

MUST BE HIGH
FOR INDUCED DRAUGHT
COMBINATION
TOWER
LARGE DOOR
FOR
INDUCED DRAUGHT
2
Fig. 19.-Elementary combination forced and induced draught cooling tower.
Compare with fig. 18.
Why is an elevated location of natural draught tower
preferred?
Ans. Because of: 1, Unimpeded circulation of the air cur-
rents; 2, utilization of the otherwise unoccupied space.
2
764
Cooling Ponds and Towers
What must be considered with respect to elevated towers?
Ans. The cost of pumping against the additional head.


(191
X
Figs. 20 and 21.-Types of wood checker work used in cooling towers.
Evaporators
765
CHAPTER 40
Evaporators
On shipboard how is fresh water obtained as required for
boiler feed "make up” and for drinking, cooking, etc.?
Ans. By means of an evaporator.
What do you understand by the term "make up" as
applied to boiler water?
Ans. In a condensing plant if there were no leakage, or uses
of steam without condensation, the supply of water in the
boiler would last indefinitely, but in practice there is consider-
able loss and additional water has to be supplied to "make up"
for this loss, hence the term is self defining.
What is an evaporator?
Ans. An apparatus heated by steam coils used to distill fresh
water from salt water
Describe the operation of an evaporator.
Ans. It evaporates salt water into steam, which in turn is
condensed in the distiller or condenser to fresh water.
Why are evaporators fitted in ships or boats making long
trips?
766
Evaporators
Ans. To avoid the weight and extra space taken up by the
considerable additional amount of water required.
Describe the essentials of an evaporator.
Ans. It is a small boiler, consisting of shell and heads and
having steam and water space.
How is the salt water evaporated?
Ans. By steam from the boiler or one of the main engine
receivers.
SINGLE EFFECT
STEAM SUPPLY
EVAPORATOR
PUMP
EVAPORATING
כסור
TRAP
CONDENSER
W
HOT WELL
DOUBLE EFFECT
T
{ST EVAPORATOR 2ND EVAPORATUR
π

HOT WELL
CONDENSER
Ly
DRINKING
WATER TANKİ
Figs. 1 and 2.-Elementary evaporators illustrating single and double effect
evaporation as described in the text.
Describe the working of the evaporator.
Ans. Sea water is admitted into the evaporator until the
required level is indicated in the gauge glass. Steam is then
turned on which flows through the coils and in a few minutes
the water in the evaporator will boil. The vapor passes over
to the distiller where it is condensed; the resultant water flows
1


Evaporators
767
கு
og sohalb
Fig. 3.-General appearance of the evaporator shown in fig. 8, but insulated
and lagged. Coil connections are of the flared joint type. General design.
The evaporator consists of a cast iron or steel shell with specially constructed
door, to which is attached an arc type of manifold and heating coils. The
heating element, being thus mounted on the hinged door, can be readily
swung outside of the shell for easy inspection, cleaning or repair. No sup-
porting rollers, tracks, or other handling devices are needed when inspecting
an evaporator. The position of the coils, when the evaporator door is closed
forms an ebullition compartment so that, without the use of baffle plates, a
complete circulation free from conflicting currents is set up. The top of
the
vapor space is fitted with a baffle or separator of simple but effective design.
768
Evaporators

VENT PIPE-
CIRCULATING
WATER
DISTILLER
CIRCULATING DISCHARGE
STEAM EXHAUST
INLET
-SEA INLET
FRESH WATER TANK
FRESH WATER DISCHARGE
SAFETY
VALVE
EVAPORATOR
FEED PUMP
CHECK
VALVE
FEED
·CIRCULATING
PUMP
-
VAPOR
EVAPORATOR STEAM
SUPPLY
BLOW OFF
M
Fig. 4. Marine installation of a multi-coil evaporator and distiller plant for
feed make up and drinking water. It consists of evaporator, distiller, aerating
filter, circulating pump, feed pump, trap and storage tank. These units may be
located wherever desired except that the distiller should be placed as high
above the evaporator as possible. The steam for evaporator coils should be
taken direct from boiler or auxiliary steam main, and the drain should be led
to the trap, which discharges into hot well or filter box. The vapor connection
on shell or evaporator should be valved, and led either to feed water heater,
I. p. receiver, or to main engine condenser; the relative efficiency of the three
methods depending upon local conditions. A branch from the vapor pipe
should be led to a special distiller for drinking and culinary purposes. The
condensed vapor from the coils of the distiller runs by gravity to the aerating
filter, and thence to the fresh water tanks. The circulating pump and feed pump
may be located wherever is most convenient; but when possible, locate the
evaporator feed pump close to evaporator, so that the engineer may con-
veniently time this pump according to the water level in evaporator gauge
Evaporators
769
to the filter tank from whence it is pumped or drained to
storage tanks.
How is the evaporator connected when it is desired to use
all or part of the water evaporated for boiler feed?
Ans. The evaporator vapor pipe is connected to the main
condenser.
Explain at length the procedure with respect to blowing
off the brine.
5
Ans. When a saturation of 2 has been reached, with the
feed pump running to keep the water at its normal level, start
the brine pump and remove the brine, or shut off the boiler
steam supply, and keeping the water level at its proper height,
wait until the machine ceases to operate, stop feed pump, then
open up the brine cock and drain off the brine, then start feed
pump and wash out evaporator; or when the evaporator feed
pump is connected as shown, it is used to draw off the brine. In
any case do not attempt to empty evaporator with steam pres-
sure on the tubes, or a badly scaled evaporator will be the result.
What happens during the evaporation of the salt water?
Ans. A very strong deposit of salt is thrown down upon the
Fig. 4. Text continued.
glass. The inlet to evaporator feed pump may be taken either from the circu-
lating pump discharge or direct from the sea. The evaporator feed pump
discharge may be led directly into the evaporator, or if preferred may be first
passed through a small feed water heater, taking its steam supply from the
exhaust of the pump. When fitting up the feed pump, provide a branch from
its discharge pipe to permit ready connection to steam manifold of evaporator
for testing purposes when door is open. This avoids testing the coils with steam.
The steam and exhaust to pumps may be arranged to suit conditions. The
blow off from the evaporator should discharge overboard, with a suitable
check valve at the ship's side. With this arrangement of piping, the evaporator
will give the best results.
770
Evaporators
heating coils which must be removed frequently for the effi-
ciency of the heat transmission.

BRINING COCK
BRINE
DISCHARGE
NON-RETURN
VALYE
FEED WATER
SUPPLY PIPE
REDUCING
VALVE
STEAM OUTLET
TO CONDENSER
DRAIN TO HOT WELL
Fig. 5.-Evaporator arranged to evaporate into the condenser; simple
but least economical. In this arrangement the steam generated in the evapo-
rator is discharged into main condenser through the outlet, and reducing
valve. The necessary feed water for the evaporator is taken from the circu-
lating discharge by the feed pipe, and enters the evaporator by the non-return
valve. The steam condensed within the coils flows by the drain to the
hot well. A pipe conducts the brine from the brining cock to the bilge.
By placing the reducing valve low on the condenser, as shown, the steam
from the evaporator is allowed to mingle with the feed water, and thus heat it
to a slight extent. The amount of heat thus utilized is, however, necessarily
small, as it is impossible to raise the temperature of the water above that
corresponding to the vacuum in the condenser. With this arrangement, as the
water flows into the evaporator by its own weight, it is necessary to place the
apparatus as low as possible, so that there may be a considerable head of
water.
Evaporators
771
What fittings are used with evaporators?
Ans. Evaporators are fitted in the same manner as boilers
with safety valve, steam gauge, stop valve, water gauge, feed
check, bottom blow off valve and salinometer cock.

24 Kan Ce
STEAM
OUTLET
NON-RETURN
VALVE
REDUCING VALVE
FEED WATER
SUPPLY PIPE
PUMP
TWO WAY
COCK
NON-RETURN
VALVE
DRAIN TO HOT WELL
Fig. 6.-Evaporator arranged to evaporate into the low pressure steam
chest. Here it is necessary to fit a small pump for the supply of water to
the evaporator. This water is taken from the circulating discharge, as before,
by the pipe, and enters the evaporator by the feed pipe and non-return
valve feed. A two way cock is placed in the steam pipe, and it is thus
possible to discharge the steam from the evaporator into the I.p. valve casing,
or into the condenser at will. A non-return valve should be placed on the
I.p. valve casing. In ordinary cases with the engine working, the steam from
the evaporator would be led into the I.p. valve casing, but when the evapo-
rator is used in port the steam is discharged into the condenser, thus allowing
any waste of water to be made up.
772
Evaporators
:.
What is a salinometer?
Ans. A kind of hydrometer for testing the density of salt
water.
What is its construction?

REDUCING
VALVE
STEAM
OUTLET
DRAIN
FEED WATER
SUPPLY PIPE
PUMP
TWO WAY
COCK
FEED
HEATER
OUTLET
VAPQR
EXHAUST
INLET FROM
HOT WELL
Fig. 7.-Evaporator arranged to evaporate into feed water heater. The
feed heater is as shown. The water from the hot well enters by supply pipe,
and after being heated flows by the feed pipe to the main feed pump suction.
A two way cock as is placed on the evaporator outlet pipe so that the steam
from the evaporator may enter the condenser by the reducing valve, or may
be conducted by the pipe to the feed heater. The drain from the coils may
be led by drain pipe into the pipe at any point beyond the two way cock,
as shown. Vapor exhaust is for the escape of air and vapor from the feed
heater, and is led into the hot well at any point above the usual water level.
For the purpose of providing pure drinking water, part of the steam generated
in the evaporator may be condensed in any fresh water condenser, and, being
free from grease, it is very suitable for this purpose.
Evaporators
773


JUS
Gof
00
P…………….
bod
==
a a
DOOR
@
*****
O
QO
to
MANIFOLO
COILS
Fig. 8.-Views of evaporator showing construction illustrating manifold in closed
and open positions. Steam of any initial pressure down to atmosphere may
be utilized so that evaporator may be operated as a single unit or with multiple
effect. In marine practice the steam pressure commonly used is from 75 lbs.
to 100 lbs. General design —Consists of shell with door to which is attachd
an arc type manifold and heating coils, the heating element being mounted
on a hinged door which enables same to be swung outside for convenient
inspection, cleaning, or repair. A baffle in the top of vapor space is provided
to prevent priming. Shell The cylindrical shell and its concave and convex
heads are of open hearth boiler steel or cast iron as specified. The side of
shell is provided with a large hinged door. Manifolds — The top and bottom
manifolds for steam inlet and condensation drain respectively are similar at
top and bottom; are of cast iron or bronze and bolted to door. Coils - These
are of seamless drawn copper and are of a form that puts practically no strain
on the joints. The helical form also provides for natural contraction and ex-
pansion under change in temperatures. This permits the scale to be removed by
suddenly flooding the evaporator with cold water and blowing down at inter-
vals, and to a great extent eliminates scaling by hand.
774
Evaporators
Ans. It consists of a weighted bulb to which is attached a
graduated stem and its action is to indicate the amount of salt
held in solution in the water by floating higher or lower.
STEAM PIPE
FROM BOILER
CIRCULATING
WATER
EVAPORATOR
STEAM TO
DISTILLER

C
DISTILLER
FILTER
•
BRINE
PUMP
DISCHARGE
OR FEED PUMP
SUCTION
PIPE
OVERBOARD
FEED PIPE TO
EVAPORATOR
STEAM TRAP
I DRAIN PIPE
FROM EVAPORATOR
Fig. 9.-Diagram of evaporating and distilling apparatus showing manner of
connecting up a plant to make drinking water; all parts are shown except
circulating pump; one pump is used for both evaporator feed and brine.
BRINE AND
FEED PUMP
NOTE. Amount of "Make Up" Required. The waste of feed water by
overflow, blowing of whistle, leaks in the boilers, condensers, stuffing boxes, pipe
joints and valves, varies greatly; it is more nearly in proportion to the quantity
of feed water used than to the horse power.
NOTE.—On vessels making long voyages an evaporator is practically indis-
pensable and even where the trip is of such duration that the supply may be
replenished at different ports, the fact that all fresh water is not desirable for
boilers, makes the use of an evaporator advisable in order to maintain the full
efficiency of the boilers, prevent the formation of scale and the serious damage
resulting therefrom.
What does the height of floating indicate?
Ans. Higher for density and lower for freshness.
Evaporators
775
What are the scale markings?
Ans. 0, for fresh water; ½ for sea water that contains 1 lb.
of salt to 32 lbs. of water; 2 when it contains 2 lbs. of salt to
32 lbs. of water. Each division is subdivided into 4 parts. The
graduations are for a temperature of 200° Fahr.
What precaution should be used in taking a salinometer
reading?
Ans. The water should be at 200° Fahr.
If not it should be brought to 200° Fahr. by heating or cooling as
may be necessary.
What is a double effect evaporator?
Ans. An arrangement of two evaporators such that the vapor
from No. 1 is carried over into the tubes of No. 2. The drain
from the first evaporator is led to the hot well and the drain
from the second evaporator is led to the fresh water condenser
and there cooled down to be used by the passengers.
What is done with the condensate from the second
evaporator?
Ans. It should be led the fresh water condenser and there
cooled down for passenger use.
How is the evaporator hooked up for evaporating into
the condenser?
Ans. It is usual to place a reducing valve between the evap-
orator and the condenser.
What is the effect of evaporating into the low pressure
cylinder valve chest?
Ans. Steam from the evaporator does work upon the low
pressure piston before being condensed which results in a saving.
776
Evaporators
Describe the method of evaporating into the feed water
heater.
Ans. In this case the steam pressure in the evaporator is
about 1 lb. above the atmosphere, and as the steam is entirely
condensed in the feed water, and is then pumped into the
boilers, the only actual expenditure of heat is that caused by
brining.
Big Boilers
777
CHAPTER 41
Big Boilers
The title of this Chapter is well selected as the sizes of boilers
have reached such proportions that some of them occupy the
space of a bungalow and over 100 feet high with capacity of
1,000,000 lbs. of steam per hour or more.
What are the two general types of these large boilers?
Ans. 1, straight tube; and 2, curved or bent tube.
How are the curved tube boilers classed and why?
Ans. As "drum type" because all tubes are connected directly
to drums (no headers).
In some recent designs how have these characteristics
been combined?
Ans. To provide for furnace wall cooling.
What are the points relating to large straight tube
boilers?
Ans. They have vertical or slightly inclined headers into
which the tubes which constitute the heat absorbing surface
are connected.
ว
778
Big Boilers

00
O
00
•
••
Do
PEGALERIE FALLZ81
•
•
O
(OTRIBU
•
HALF SECTION "AA"
150,000 LBS. STEAM PER HOUR
metin2

LONGITUDINAL
SECTION
450 LBS. DESIGN PRESSURE
Figs. 1 and 2.-Sectional header straight tube steam generator. The bulk of
the heating surface consists of straight tubes connected to the headers. Size of
boiler is 150,000 lbs. steam per hour at 450 lbs. pressure.

Big Boilers
779
Fig. 3.-Header type boiler construction 1. Fusion welded steam and water
drum.
Fig. 4. Header type boiler construction 2. Complete header section com-
posed of front and rear headers, connecting tubes and mud drum.d

780
Big Boilers
What are the two general types of headers?
Ans. Box and sectional.
Describe box headers.
Fig. 5. Header type boiler construction 3. Vertical and inclined baffle
assemblies.
Ans. They consist essentially of two large flat plates welded
or riveted to plates at the edges and secured by stay bolts or
tubes at intervals as required to support the plate surfaces;
one of these plates is drilled for tube holes and the other for
hand holes opposite the tube holes.
Describe sectional headers.nos olid say booH A
boots bno in lo bog

Big Boilers
781
Ans. Boilers of this type have the front and rear headers
divided into "sections" (usually one tube wide except for
marine boilers) made sinuous to provide for staggering the
tubes in the tube bank. See figs. 4 to 8.01 roit ob zait woman
ersttod
Toron
our ho
Salford
POPORD
503-10
insan
Line
adhat
STRA
na b
od robaud
Figs. 6 and 7.-Header type boiler construction 4. Hand hole side and
tube hole side views of a typical forged steel tube header.

782
Big Boilers
How are marine sectional header boilers constructed?
0 Ans. They have usually single tubes in the lower two or three
rows, and clusters of small tubes above. As the headers are
narrow they do not require additional stays.
odt ni onlin
In the case of both the box and sectional header boilers
of the cross drum type how is the drum located and
connected?
Ans. It is located above the rear (low) header or headers
Fig. 8.-Header type boiler construction 5. Section through tube header
showing hand hole closure assemblage opposite a tube hole.
and is connected to both front and rear headers by steam and
water circulators.
Describe a modified arrangement.
Ans. Box header boilers and a few sectional header boilers
have been made with longitudinal drums which are connected
to the headers by circulating tubes or (in the case of the box
header boilers) by extending the headers to throats which are
connected directly to the drum sheet. avtobooH T bap b
200
piel fosigyt o to w
shi for vot
Big Boilers
783


Fig. 9.—Development of a typical bent tube boiler 1. Just prior to 1890
this boiler had two upper drums and a lower drum.
Fig. 10.-Development of a typical bent tube boiler 2. Addition of a
third upper drum with connection next to tubes.


Fig. 11.-Development of a typical bent tube boiler 3. Upper drums on
same level steam outlet and safety valves moved to rear drum and some tubes
of rear bank bent forward to enter middle upper drum.
Fig. 12.-Development of a typical bent tube boiler 4. Increased number
of rows of tubes. Some tubes of the middle bank bent forward to enter the
front drum.

784
Big Boilers
WILL
201
Fig. 13. Sectional view showing example of modern bent tube steam boiler with "water walls." Construction
details shown in figs. 14 to 16.

Big Boilers
785
b
Describe in detail the advantage of straight tube over
bent tube designs. Tanimota duid le noitelusio has 1
Ans. The straight tube boilers have an advantage over the
bent tube boilers in that all tube bank tubes are plain, identical,
and can be withdrawn directly through the hand holes without
disturbing any other tubes in the bank. A tube cleaner will pass
Fig. 14. Detail 1. Top view of boiler pressure parts showing the circulator
relief tubes connecting the upper side wall headers with the steam drum.
through these tubes readily and to some extent visual examina-
tion is possible. Straight tube boilers usually require less head.
room for the same heating surface.
How about the circulation?
Ans. The circulation is not as positive and active, however,
as in the bent tube type and some trouble has been experienced

786
Big Boilers
in large high pressure boilers of this type due to inadequate or
reversed circulation at high steaming rates, especially in high
tube banks.
me ed agliod do hipleyla un an A
Are straight tube boilers preferred?lad ni aliod odut sood
Ans. They are preferred for some applications, but in general,
and few ten solo odmy & Sund and it Padua 1910 vnd gridw
2020
Fig. 15.-Detail 2. Side elevation of boiler pressure parts showing space for
installing super-heater inside the first tube bank.
the trend has been toward the use of bent tube boilers, along
with the trend toward fewer and larger units and higher
pressures for a given steam demand. The high head and

Big Boilers
787
relatively uncongested circulation make bent tube boilers more
suitable for high evaporation rates.
State what size tubes are used in the standard sectional
header boilers and give spacing?
enu
Fig. 16. Detail 3. Section taken above the floor screen tubes showing the
circulator water supply tubes connecting the lower side wall headers with the
lower drum.
TAW
NOTE. A few sectional header boilers of modified design have been used for
a pressure of 1,200 lbs. per sq. in. but they are usually used only for much lower
pressures.
"Ibs. per sq. in."
*NOTE. When you encounter this alphabet soup item: "psi" it is supposed
to be a symbol (by courtesy an abbreviation) or what not for: "pounds per square
inch" Writers, especially professors, perhaps think their time is so frightfully
valuable that they don't even take time to include p for per, leaving that to you
to supply mentally. The author considers this super labor saving condensation
highly objectionable. lbs. per sq. in. leaves nothing to the imagination and the
least informed reader will know what you are talking about. Some smart aleck
put the thing on the map and the power of suggestion will see that it stays there.
so why try to do anything about it?
Payme
788
Big Boilers
WATER-COOLED
FRONT WALL
-STEEL CASING
WLEDGE+ FR$ 24+ 1
SERVER=17/«
SE E DUE DE MARIE A
WATER-COOLED
FURNACE
WATER COOLED BRIDGEWALL
TWO ZONE FURNACE
FOR SMOKELESS
COMBUSTION
HENKLOVE DVA ULEI, CHARFMI
• O
••
KADO-PRES
O
···
•
OO
OOO
PROPERLY DESIGNED
TUBE SPACING FOR
TUBE REMOVAL
1
CROSS-FLOW OF GASES
GAS OUTLET
Fig. 17.—Plan view of integral furnace boiler showing path of gases. The furnace is water cooled all around
with water cooled bridge wall. In the conventional stoker fired unit, the boiler tubes can "see" the fuel bed,
and the gases pass directly from fuel bed to tube bank. In this integral furnace boiler, the gases, before
entering the tube bank, must first pass through a screen, then around a baffle and thence along an open
pass, thus mixing the gases while they are still burning and providing more nearly complete combustion,
means smokeless combustion.

Big Boilers
789
Ans. 4 in. tubes spaced horizontally on 7 in. centers.
One well known boiler uses 31½ in. tubes.
1
Mention late practice with respect to baffling.
Ans. Sectional header boilers are usually at least partly
cross baffled. Box header boilers may be either cross or hori-
zontally baffled; the cross baffled box header boilers have a
somewhat wider tube spacing than the horizontally baffled
boilers to permit the use of rotating soot blowers. Horizontally
baffled boilers have stay tubes in the headers to permit placing
the baffle tile, and hollow stay bolts to accommodate the soot
blowers, which blow parallel to the tubes.
Give comparison between straight and bent tube boilers
with respect to cost of construction.
Ans. The conventional design of straight tube boilers (parti-
cularly sectional header) are usually heavier and more expensive
than bent tube boilers for most sizes.
Give construction details of bent tube
tube boilers with
respect to drums.
NOTE. As the rate of heat transfer from the gas to the tube depends, among
other things, on the film thickness or resistance at the boundary layer, a high gas
velocity and turbulent flow are desirable. This means that for the same gas velocity.
cross flow increases the heat transfer rate. For a given tube size, tube spacing is
limited by ligament strength and the necessity of providing access for cleaning
With a longitudinal baffled boiler the exit gas temperature rises rapidly as the
rating increases, so these boilers are not economical for sustained high ratings.
They are particularly suitable for heating or processing installations where low
head room is imposed by building limitations, because it is possible to get a large
amount of surface in relatively small volume, due to the close tube spacing in the
direction of gas flow.

790
Big Boilers
uositud lenga endur o
LF
Phot
Man Fig. 18.-Water cooled furnaces 1. Erection view.
www
b

Big Boilers
791
Bogner
sdin and Indiem
Fig. 19. Water cooled furnaces 2. Looking up at the water walls from
bottom of furnace of a large steam generating unit.
792
Big Boilers
Ans. Customarily, all bent tube boilers are arranged with
one lower or mud drum and from one to three upper drums.
There are a few exceptions as in the case of double set boilers and
boilers having integral economizer sections. The tubes are always
arranged in rows in both directions, and at least in the case of the
front tube bank, these rows are so spaced (at right angles to the direc-
tion of gas flow) to provide lanes which permit withdrawal and inser-
tion of tubes anywhere in the bank without the destruction of other
tubes.
Describe details of a well known boiler for low pressure.
Ans. Typical is the four drum and low head, three drum
boilers, made with 34 in. tubes, spaced alternately on 54 in.
and 634 in. centers; the other three drum boilers have 3 in.
tubes spaced on 534 and 64 or 5% and 6% in. centers.
What should be noted about the use of 2 in. tube banks?
Ans. It is desirable from the standpoint of heat absorption
because more heat absorbing area can be placed in a given
space and they can be cross baffled to give more turbulent
flow. However, the spacing is such that many of these 2 in.
tubes cannot be withdrawn without the destruction of others,
but the gas temperatures in the rear bank are relatively low
and there is little danger of overheating tubes.
In the case of failure of these 2 in. tubes how can they
be cut off?
Ans. The tube holes may be plugged.
The present practice in treating feed water usually prevents forma-
tions which might cause serious trouble.
NOTE.-Bent tube boilers may be designed for cross or parallel gas flow or a
combination of both, depending on the proportions of the boiler and location of
the gas outlet. In general any change in baffling which increases heat absorption
will also increase draught loss for the total gas flow.

Big Boilers
793
Water Cooled Furnaces
Goltzibut
In the development of the water cooled furnace the first step
was the installation of a water screen in the furnace incident
to the development of pulverized fuel firing.
Fig. 20.-Water cooled furnaces 3. Detail of water cooled furnace wall con-
structed with bifurcated tubes to reduce the number of rolled joints and hand
holes in headers. This all metal wall is sealed against leakage and is con-
structed to minimize heat loss.
The next step was the placing of riser tubes from the bottom screen
header against the inside surface of the rear furnace wall. The apparent
advantage of this arrangement led naturally to the extension of water
cooling to side and front wall surfaces.
In recent years water cooled furnaces have become standard
practice in connection with nearly all medium sized and larger
boiler installations.
nd smos 30 119

794
Big Boilers
Their use has virtually eliminated furnace maintenance, has reduced
radiation losses and has greatly increased capacity and availability.
These advantages are obtainable in larger measure only with the
bare tube type of furnace, since covering of any kind appreciably
retards heat absorption and offers no advantage from either mainten-
ance or operating standpoints. box log to trangoterohol on
188
Somut Balera slow to bet
sobn
Fig. 21. Water cooled furnaces 4.-Interior of water cooled furnace at the
American Vesose Corp., Marcus Hook, Pa. This furnace is fired horizontally
by horizontal pulverized coal burners.
The tubular absorbing surface is built with fin tubes, plain
tubes and bifurcated tubes, or with various combination of these
tubes, spaced to meet the operating requirements.
With pulverized fuel fired installations, it is customary to
cool the bottom of the furnace as well as the walls. Dry bottom
furnaces may have plain tubes located above the floor to form
a screen or in some forms of hopper bottom furnaces, the water
Big Boilers
795
screen is omitted and the furnace wall tubes are continued
down to fan the surface of the inclined walls of the hoppers.
In either case the ash is cooled and the lower part of the furnace
is protected from excessive heat.
In slagging bottom furnaces, water circulating tubes cool the
furnace floor on which the slag bed rests. The slag spout is
cooled by water supplied from an outside source.
With stoker fired installations, those portions of the lower
wall surfaces which are subjected to direct contact with the
fuel or ash are protected against abrasion by heavy gauge
finned tubes. Corner openings are sealed by silicon carbide
blocks which are bolted to the tubes.
How are tubes connected to headers and drums?
Ans. By rolling.
An exception is to be found in high pressure forced circulation units
where stub tubes are welded to the drum in the shop and the furnace
tubes welded to these in the field.
Describe the process.
Ans. In this process the metal of the tube is forced into firm
contact with the metal of the tube seat by the use of an ex-
panding device consisting of a series of rolls and tapered
mandrel. In high pressure boilers, the tube seats are grooved
to obtain a stronger joint. The metal of the tube end is de-
formed plastically and hardened by cold working with the
expander and is held firmly by the tube seat, which is not
correspondingly deformed.
How is it determined when the tube has been sufficiently
rolled?
Ans. By measuring the elongation (extenso-meter method)
of the tube end as it is rolled in the seat, by a dial gauge
fastened to the tube and in contact with the drum or header.
:

796
Big Boilers
Continon de
6 2
How 9ommy or base
11
Fig. 22. Water cooled furnaces 5. Interior of a large corner fired water
cooled furnace.

Big Boilers
797
Fig. 23.-Water cooled furnaces 6. Interior of a large water cooled furnace
after six months continuous operation. This furnace is fired vertically.
798
Big Boilers
Forced Circulation Boilers
How is natural circulation affected as the working
pressure increases. How remedied?
Ans. The difference between the density of water in the down
flow and the water steam mixture in the upflow sections be-
comes less and for very high pressures it becomes necessary to
place the drum at considerable height in order to provide the
required hydraulic head to assure adequate natural circulation.
What was done because of this condition?
Ans. It led to the development of forced circulation systems.
With forced circulation small tubes are employed; a drum may or
may not be required, depending upon the design; flexibility in the
arrangement of heating surfaces is possible; and positive circulation
is attainable.
How are large water tube boilers usually classed?
Ans. With respect to the number of drums and the tubes
whether straight or bent.
House Heating Boilers
799
:
CHAPTER 42
House Heating Boilers
What can be said if anything, in favor of early cast iron
sectional house heating boilers.
Ans. Not much, if anything.
Why?
Ans. Where is the heating surface? In the stack?
Some years ago the author expressed his opinion about these so
called house heating boilers (see Audels Engineers & Mechanics Guide
No. 5, Chapter 67) and still holds the same opinion.
What has been done to make these boilers less wasteful
of fuel?
Ans. Various attempts have been made to decrease short cir-
cuiting by increasing the number of passes and to increase heat-
ing surface by corrugations, fins, pins, cast integral, etc.
What three items should every house heating boiler
manufacturer state in his catalogue?
Ans. 1, Grate area; 2, Heating surface; and for convenience,
3, Ratio or number of sq. ft. of heating surface per sq. ft. of
grate.
In numerous instances no mention is made of the amount of heating
surface or grate-heating surface ratio.
800
House Heating Boilers
What do they mean by "heating surface" unqualified?
Ans. Nothing, unless you know what they are talking about.
If manufacturers would stop talking so much about "prime" or
direct and indirect heating surface and state the total amount of heat-
ing surface provided per sq. ft. of grate area, and its arrangement, the
purchaser would be more enlightened.
When they state the heating surface of a vertical boiler
what do you understand by that?

VETEIGH, FIE DatapanplaNANOBRIEN, PAUL,NOTĒMA
An
2
3
TI
HEAT WASTED:
15:1
3:
T
HEAT WASTED
8:1
K
Gigante Smaufach 4010 |
TALAR MƏNAL,
20:1
4
50:1
Figs. 1 to 4.—Effect of inadequate heating surface. This may be illustrated by
taking several kitchen hot water kettles of equal capacity, but of different
diameters, so that the area of the bottom or part exposed to the fire (heating
surface) will be say 8, 15, 20, and 50 square inches. Put the same quantity of
water into each and place under each a bunsen burner whose tip has an area
of 1 square inch. When the burners are lit (assuming equal flames) it will be
noticed that only a very small portion of the flame will touch the bottom of
kettle No. 1, more will come in contact with No. 2, still more with No. 3, and all
with No. 4. The result is that No. 4 will begin to boil first, No. 3 next, then No. 2,
and last No. 1. Evidently it takes less fuel to heat No. 4 than any of the others,
the waste being about in the proportion indicated by the arrows. The same
thing happens in a house heating boiler. Don't blame the manufacturers
because there are a lot of boilers like kettles Nos. 1 and 2 on the market—It's
your fault. If you thought less about first cost, and more about your coal bills
you would buy a boiler like No. 4 kettle, and the cost of coal wouldn't be
so high. No house heating boiler should have less than a 25:1 heating surface,
grate area ratio however what's the use of preaching this to greenhorns,
thermal idiots and miscellaneous nondescripts.
House Heating Boilers
801
Ans. Nothing, unless they say it is the old or total heating
surface or the Code heating surface rating.
What is wrong with the old rating and why is the error
of no importance?
Ans. They base it (for convenience) on the outside diameter
of the tubes instead of the inside diameter, but the difference
(in sq. ft.) is very small.

RED HOT-
TaksiÚ
THE CELLAR
HEATING SURFACE
THE WATER
HEATING SURFACE
Fig. 5.-The principal reason why the tenants get no hot water. It's not the fault
of the manufacturer, he simply builds what the public is willing to pay for and
does not worry about the coal bills.
What is the Code rating?
Ans. In the Code rating they base it on the inside diameter
(which is correct) but only upon that part of the tube surface
covered with water which is up to the middle gauge cock, no
allowance being made for the super-heating surface or the
length of that part of the tube above the water level.
What are the objections to the Code rating?
802
House Heating Boilers
Ans. In the first place, practically no two designs of vertical
boilers are built having the same percentage of tube surface
above the water line; the water line is continually varying
between lower and upper gauge cocks; the elevation of the gauge
cocks is such as specified by the designer, and this in turn de-
pends upon the service for which the boiler is designed.
For instance, in the author's boiler the design is for abnormally
high water level made possible by the internal separator circumferen-
tial collector and dryer.
Causes for Unsatisfactory Operation
of Heating Boilers
Insufficient draught, from having the heater room too tightly
closed with no fresh air inlet.
Insufficient draught, due to too much ashes in the ash pit or
on the grates.
Weak, spotty and "cranky" fires are the result of fuel that
is dirty or of poor quality.
If radiators be not air bound, and still do not seem to heat
properly, even with a hot fire, gas travel or flues may be
choked with soot.
Poor draught, caused by damper in smoke pipe being im-
properly adjusted, or clogged with soot and remaining closed.
Poor draught caused by a smoke pipe that is too long or
too crooked.
Poor draught caused by a smoke pipe that is smaller than
the smoke pipe collar on the smoke box.
Poor draught caused by air leakage into the chimney from
an opening which connects a water heater, dust remover or
open fire place to the same chimney.
House Heating Boilers
803
F
When a good draught produces an unsteady water line and
varying supply of heat, this is probably caused by oil, grease
or other dirt in the heater.
What is the usual construction of a vertical cast iron
sectional boiler?

UP TO
GRATE
NO DRAUGHT
KEREKEK
BURNED OUT
GRATE BARS
LOMUNALN
תהווה
2b8
▬▬▬▬▬▬EN
HE..
▬▬▬▬▬▬▬▬▬▬▬
NURN
TERVEYSKARA
שחייה
………………ˇˇˇˇ
ASHES
OVERFLOW
DRAUGHT CHOKED 90%
Fig. 6.-Usual condition of the ash pit when the owner cannot put off taking
up the ashes any longer. Note the burned out bars due to letting ashes accumu-
late in the ash pit. The illustration does not show the new grate just ordered
from the plumber, but it is on the way.
Ans. It comprises a base section containing the grate, a fire
pot with space all around for the water, and piled up on top of
this is one or more intermediate sections and a top or dome.
How can the efficiency of this type of boiler be increased?
Ans. By piling on more intermediate sections increasing the
804
House Heating Boilers
heating surface in amount depending upon the number of
sections piled on.
What names are given to these vertical cast iron boilers
with respect to the number of intermediate sections
provided?
Ans. Low, medium and high.
DRAFT DOOR
CHAIN

DRAFT DOOR
DRAFT DOOR
FRAME
GRATE
CONNECTING
ROD
FINGER BAR
GRATE RING
SHAKER
CONNECTING
ROD
GRATE BAR
NATIONAL RADIATOR COMPANY
GRATE
CONNECTING
COTTER PINS
Fig. 7.-Square base with names of parts.
BASE, FRONT
FRAME
EWO
PETERS
GRATE LOCK
ASH
DOOR
ANGLE
LEVER
How much heating surface should be provided in a
house heating boiler?
Ans. The author has always maintained the proportion should
be 25:1, that is, 25 sq. ft. heating surface for each sq. ft. of
grate area.
House Heating Boilers
805

MULTI DIVISION
HusrananaKARENES
TTTET
1 M. ADA DIG AND HEARERSTO
1 8 APAPAPUN DO THE SAM –
BLAR DUMAA ALAT EL. ZAMOUNT U U
PUUTUVLASTNOMAD DE -
| FVEDLES SALOPOTO BILJNI
A GAWIN SLIN NË verurt
BRITI
MEZIZENZIIHMI
MONO DIVISION

SMALL DIVISION

Figs. 8 to 10.-Division of the hot gases. For
equal travel of the gases ovel the heating
surface the mono-divisional arrangement
of fig. 8 is very wasteful. As the gases are
split up into more divisions as in figs. 9 and
10 each being surrounded by heating sur-
faces, evidently (assuming adequate com-
bustion chamber) more heat is absorbed and
the stack temperature reduced, because the
gases come into contact with a larger
amount of heating surface per foot of travel.
It follows then that the less the division of
the gases, the longer must be the travel of
the gases, for equal efficiency. In figs. 8
and 9 note the ridiculous lack of heating
surface. And this is the kind of junk you
find in nearly all home basements.
With respect to efficiency, the following tests as given in one manu--
facturers' catalogue for cast iron vertical boilers all having the same
size grate but with different numbers of sections, speaks for itself and
also for the author's ideas as to grate heating surface ratios, and.
eloquently supports the author's views on the subject of heating:
surface.
806
House Heating Boilers
44
"&
1 square foot of grate should burn......
"
44
46
"
Proportions and Performance of Heating Boilers

#
44
66
"
46
44
"
10
"
31
"
44
3
develop.. 30,000
15
120
will require....
supply.....
Ka
VIRTU
ហ
Low
boiler
(
APTCHAPITR
TUTOR
Medium
boiler
High
boiler
4
5 pounds coal per
hour
40,000 50,000 B.t.u. per
hour
25 square feet heat-
ing surface
200 square feet ra-
diating surface
20
"
160

110100
Fig. 11.-Coil boiler. In type, this is a combined shell and water tube boiler.
The cut shows plainly the general construction, thus requiring no description.
This form of heating surface is very efficient.
House Heating Boilers
807
Since the number of sections as listed in the table on page 812,
includes the top or dome; note that boiler O, had no intermediate
sections. It will be noted that the evaporation in this boiler was only
7.5 pounds per pound of coal, and that even with the rate of combustion
increased with the addition of intermediate sections, the evaporation
increased from 7.5 to 9 pounds. It is simply a question of whether the
purchaser prefers a cheap boiler with a big coal bill, or an expensive
boiler and small coal bill that is for him to decide.
The ratio of heating surface to grate, according to Kent is given
for low, medium, and high boilers; as 15, 20, and 25 to 1 where the
rate of combustion is respectively 3, 4, and 5 pounds of coal per square
foot of grate per hour.
SHORT CIRCUITED CORNERS
The author believes that in no case should there be less than 25
square feet of heating surface per square foot of grate in order: 1. To
obtain high efficiency under normal operation; 2, to permit forcing in
extreme cold weather without material loss of efficiency; 3, to obtain
greater response especially in starting the fire think this over.
##HALAMIRA
5
4
KHHHHHH
M


*******
·
CHECHIHEME
KHHIHHHHHH
Figs. 12 and 13.-Characteristics of short and long pass boilers. For a given
travel of the hot gases the shorter the passes the greater the number of turns
where short circuiting occurs, hence the greater the proportion of the heating
surface rendered inefficient. Accordingly for equal travel, a few long passes
are more efficient than many short passes.
808
Steam Heating Systems
How should the passages through which the hot gases
traverse the heating surface be arranged?
Ans. They should be arranged so that they have the proper
length of travel (guided by baffles or equivalent) and come in
contact with all the heating surface, that is, short circuiting
should be avoided.
Upon what does the proper length of travel depend?
ATTACH PIPE SMOKE
ON FLANGE
1111

HOT
WATER
SUPPLY
WATER
SPACE
HANDLE
OF ROCKING
DUMPING
GRATES
COLD
WATER
RETURN
*
WATER
DRAFT:
DOOR
***H
**……………
~W04
TÁVÁM MIN
MR PAU
8-888S
7 1 ↑ 1
FIRE POT
CLEAN FLUES
HERE
WATER
HO1
WATER
SUPPLY
-WATER
SPACE
ROCKING &
DUMPING
GRATES
COLD
WATER
RETURN
ASH
DOOR.
Ans. The arrangement of the
heating surface.
Name three arrangements
of the heating surface.
Ans. 1, non-division; 2,
small division; and 3, multi-
division; as shown in figs. 15
to 17.
Typical examples are: 1, non-
division as in the ridiculous pot
bellied hot water heater; 2, small
division, as sections of cast iron
boiler; 3, multi-division, tubu-
lar heating surface as in tubular
boilers. See figs. 8 to 10.
For equal efficiency upon
what does the individual
arrangement depend?
Fig. 14.-Vertical tubular boiler. An example of multi-division of the hot gases
giving a very effective form of heating surface. In the opinion of the author this
type of boiler when properly proportioned (25 to 1) is second to none.
House Heating Boilers
809
Ans. The less the division of the gases the longer must be the
travel of the gases for equal efficiency.
This must be evident from figs. 15 to 17.

-NON DIVISION
NON
LONG TRAVEL
MEDIUM TRAVEL-
SMALL DIVISION
MULTI-DIVISION

THXEDAR
SHORT TRAVEL-
#:*:::::::::::::::||
HOHOHEN
EURASIATICHI+YA+NA+EN
ŸŸŸŸÿÿÿÿÿÿ↓↓↓♥
WIT
Figs. 15 to 17.-The efficiency of the heating surface does not depend on the
Tength of travel, but on the ratio of the cross sectional area of the passage to its
length and the arrangement or disposition of the surface with respect to the hot
gases. In a vertical tubular boiler for instance there may be only one large and
long tube as in fig. 15, and the temperature of the gases escaping at the end
of the tube will assume a certain value depending upon the rate of combustion
and the efficiency will depend on these values. The single tube of fig. 15 may
be replaced by several smaller and shorter tubes as in fig. 16, or a still larger
number of very small and very short tubes as in fig. 17, the ratio of length to
diameter (or cross sectional area) being the same in each case, and there will
not be any loss of efficiency. That is by properly proportioning the size and
number of the tubes. Any length tube may be used without increasing the
stack temperature.

810
House Heating Boilers
11/
How is multi-division of the gases best obtained?
Ans. By means of tubular heating surface, as for instance in
fig. 14.
E on
tobivý ad eum einT
What should be especially considered in the selection of
a heating boiler? JAME
Ans. The amount and arrangement of the heating surface,
size of combustion chamber and grate area.
How about manufacturers' ratings?
Ans. The ratings of heating boilers as given in manufacturers'
catalogues may as a rule be safely accepted, but the efficiency
of the apparatus should be looked into.
Eng
om & Land
vor of the
of dipnal lo puce
wandt Bro
17
31
evout to drow
bop digusl
o adul pol
w adult lo
side edt bas
beople al
hoy la 158mum
30) alainpID
o ons om gli notiogoig
ogora va a tool. Shortle to 20
Fig. 18-Sectional cast iron heating boiler designed to secure adequate heating
surface, a feature sadly lacking in some cast iron heating boilers.

House Heating Boilers
811
ain asiog od odz to noi
B
me old wes
Fig. 19. Fast steaming water film type heating boiler. Heating surface per unit is increased by the zig zag
shape of the units. Width of water film 34 inch.
Fig. 20. Detail of fast steaming water film boiler. Each generator contains only a 3/4 in. film of water. On
steam jobs the water in the generator is completely isolated from the water in the main jacket as far as cir-
culation is concerned. This water boils rapidly sending unusually dry steam into the mains and system long
before the water in the outer reservoir reaches the boiling point. On hot water jobs the generators also pro-
duce quick heat and rapid circulation. Each generator is fastened to the boiler at A and B, with bronze screw
bushings. Return water enters jacket at a remote point C, from generators.

812
House Heating Boilers
Note also the following table from Kent:
Steam Heating Boiler Tests
Number
of
boiler
2110
11/2
vib
beap hood Below of b
Fuel
anthracite
pounds per
square foot
of grate
4.39
5.12
5.28
5.44
ப்
Area Number
of
grate
square including
of
sections
feet
dome
1.23
1.23
1.23
1.23
7234
1
2
STEAM
FIRE
Steam
produced
per pound
of
coal
7.5
8.
8.5
9.
8 hour
rating
square feet
200
250
275
300
Fig. 21.-Sectional welded steel heating boiler for either steam or hot water.
Note the submerged tubes giving multi-division of the hot gases which is a
prime condition for efficiency.
Steam Heating Systems
813
Since the number of sections as listed includes the top or dome,
boiler O, had no intermediate sections. It will be noted that the
evaporation in this boiler was only 7.5 lbs. per lb. of coal, and that
even with the rate of combustion increased with the addition of inter-
mediate sections, the evaporation increased from 7.5 to 9 lbs. It is
simply a question of whether the purchaser prefers a cheap boiler and
big coal bill, or an expensive boiler and small coal bill that is for
him to decide.
Note the following carefully.
Boiler #0 with one section
÷
radiation per lb. of coal = 200 4.39 45 sq. ft.
Boiler #2 with four sections
radiation per lb. of coal 300 ÷ 5.44 = 55 sq. ft.
Note also that this boiler produces
9 - 7.5 1.5 lbs. more of steam per lb. of coal.
=
=
=
than boiler #0 with only one section, that is evaporation of #0
boiler is 7.5 lbs. and #2 boiler 9 lbs. of steam per lb. of coal.
These facts ought to convince even a greenhorn or idiot of the
value of adequate heating surface. Any boiler in which the
stack becomes red hot when forced is not only a poor invest-
ment but a fire hazard.
The ratio of heating surface to grate, according to Kent is given for
low, medium and high boilers, as 15, 20 and 25 to 1, where the rate of
combustion is respectively 4 and 5 lbs. of coal per sq. ft. of grate per hour.
See table page 806.
The author believes that in no case should there be less than 25 sq.
ft. of heating surface per sq. ft. of grate, in order:
1. To obtain high efficiency under normal operation.
2. To permit forcing in extreme cold weather without material loss
of efficiency.
3. To obtain quicker response especially in starting the fire.
4. To avoid fire hazard due to red hot stack.
What is the usual method of automatic control so that
steam may be maintained at a constant pressure during
the long intervals when the boiler is unattended?
814
House Heating Boilers
BAN
Ans. A diaphragm regulator is provided and so constructed
that variation in steam pressure operates a lever one end con-
nected by chain to the draught door and the other to the damper.
The draught is regulated inversely as the pressure varies.
7: **
A
1
R
"
Steam Heating Systems
815
CHAPTER 43
Steam Heating Systems
How are steam heating systems classified with respect
to working pressure?
Ans. As: 1, Low pressure (1 to 10 lbs.); 2, atmospheric
pressure (so called vapor); 3, vacuum; 4, combined vacuum-
vapor.
How are steam heating systems classified with respect
to piping?
Ans. As: 1, One pipe; 2, two pipe. There being many sub-
divisions under each class.
How are steam heating systems classified with respect
to the method of transmitting the heat?
Ans. As: 1, Direct; 2, indirect.
What is a direct heating system?
Ans. A system in which the radiators are placed directly in
the rooms to be heated.
What is an indirect heating system?
Ans. A system in which the radiators or coils are placed in
basement or elsewhere and the air is forced through them and
through ducts to the different rooms.
816
Steam Heating Systems

RISER
DRIP
C4
BRANCH
DRY RETURN
DOOR
yi
DOWNWA
PITCH DOWNWARD
P'
G
H
RISER
SIPHON
AUTOMATIC
AIR VENT
HORIZONTAL LINE
A
·
D
BOILER
RISER
DRIP
BRANCH
PITCH DOWNWARD
E
WATER LEVEL
IN BOILER
WET RETURN
RISER
B
F
DRIP
PANEELANDANA
Fig. 1.-One pipe relief steam heating system showing 1, dry returns to the left., and 2, wet returns to the right
The wet return is the natural method of piping but frequently it is desirable to have the return elevated to near
the ceiling where passing across doors, etc. This arrangement is called a dry return because it does not fill
with condensation as when placed below the water level.
Steam Heating Systems
817
Low Pressure Steam Systems
What are the two principal low pressure systems?
Ans. The one pipe and the two pipe with various circuit
modifications to suit conditions.
How does the one pipe relief system work?
Ans. Steam is supplied to each radiator and the condensate
removed by a single pipe or riser, hence the name "one pipe
system."
How does the condensate get back to the boiler?
Ans. It drops down by gravity against the flow of steam
and returns to boiler through drip pipes which are virtually
continuations of the risers below the branch mains.
What are the branch mains?
Ans. Large mains which feed the risers and which are slightly
pitched (to horizontal) so that condensate will drain to the
drip pipes.
What are return pipes?
Ans. Pipes which connect with the drip pipes and boiler and
which "return" the condensate from the drip pipes to the
boiler below the water level. They are slightly pitched so that
the condensate will drain toward the boiler.
What is the difference between a wet or sealed and a dry
return pipe?
Ans. A wet return is placed below the water level in the boiler
whereas a dry return is placed above the water level.
818
Steam Heating Systems
What is the advantage of a wet return?
Ans. It seals the drips from the risers and prevents steam
at a slightly higher pressure entering the return.
Describe in detail the operation of the one pipe relief
system, as shown in fig. 1.

DRY RETURN
SIPHON
UUPUINI
innnn
23 FT
IDHLITTUALMENTMI
·
5 LBS.
4 LBS.
WATER
LEVEL
İN BOILER
BOILER
22
DRIP 1
FT.
3 LBS.
F
4.6 FT
DIFFERENCE
IN WATER
LEVELS
WET RETURN
DRIP 2
| POTUI SILFLPEPESTUJEJUFEREN
UMAJORJUumi
Fig. 2.—Detail of boiler and returns of fig. 1, showing effect of pressure
variation in different parts of the system. In general, there is a gradual re-
duction of pressure as the steam flows from the boiler to the remote parts of the
system. This is due to the frictional resistance offered by the pipe and fittings
to the flow of the steam. Hence this variation in pressure only exists when the
steam is flowing in the pipes and in order for the steam to flow in the pipes
there must be condensate. Now, in the figure, when the plant is in operation
with condensation taking place in the radiators and draining into the drip
pipes, suppose the pressure in the boiler be 5 lbs.; in drip 1, 4 lbs., and in drip
2, 3 lbs. Then, to balance these pressure differences the water will rise in drip 1
to L 2.3 ft. above the water level in the boiler because there is a pressure dif-
ference of 5-4-1 lb. and the weight of a column of water 2.3 ft. is 1 lb. for
each sq. in. of cross section. Similarly, for drip 2, the pressure difference is
2 lbs., hence the water will rise twice this distance above the water level in the
boiler, or 2.3 x 2 = 4.6 ft. to balance the 2 lbs. pressure difference.
Steam Heating Systems
819
Ans. Steam (usually at from 1 to 5 pounds pressure), passes
from the boiler to the branches, AB, and AC, fig. 1; these
branches being slightly inclined, any water in the steam drains.
into the drip pipes. The steam passes through the risers to the
radiators, where its heat is radiated in warming the rooms, thus
causing condensation. The risers being of liberal size, the con-
densation is carried by gravity against the direction of flow of
the steam, and deposited in the drip pipes, where it gravi-
tates via the returns to the boiler.


DRY
STEAM
MAIN
ZA
P&C
-RISER
CONDENSATION
FALLING IN
PATH OF
STEAM
CONDENSATION
OUT OF PATH
OF STEAM
RIGHT
WAY
WET
STEAM
WRONG
WAY
Figs. 3 and 4.-Right and wrong way of connecting risers to mains. A good
many steam fitters to avoid extra labor and expense connect risers direct to the
main with simply a tee as shown in fig. 4. It requires no deep thought to
understand that some of the condensation from the radiators above falling into
the main directly in the path of the steam flowing through the main will be
taken up and carried by the steam into the next riser, thus arriving at the
radiator with considerable more moisture than would be the case if the piping
were arranged as in fig. 3, where the condensation would run down the
side out of the path of the steam. According to one authority, the saturating
and cooling effect occasioned piping the wrong way as in fig. 4 may
reduce the efficiency as much as 5 per cent.
820
Steam Heating Systems
Why does the water level stand at different levels in the
drip pipes as at F and L, fig. 2?
Ans. There is a slight pressure difference in different parts
of the system and the condensate rises to different levels to
balance these pressure differences.
How does the siphon shown in fig. 1 work?

Socs
DRAIN FROM
MAIN
?
RISER-
45° ELBOW
STEAM
M???
DESC
CONDENSATION
DRIP PIPE-
Fig. 5.-Proper method of connecting riser to main where riser has direct con-
nected drip pipe. By using a 45° street elbow only one nipple is required.
With this arrangement the main is very effectively drained of condensation,
thus increasing the efficiency of the system.
Ans. Condensate from the drip pipe falls into the loop
formed by the siphon and after it is filled, overflows into the
dry pipe. The water will rise to different heights G and H, in
the legs of the siphon to balance the difference in pressure at
points P and P'.
Why is the siphon necessary?
Steam Heating Systems
821
Ans. If the siphon were pmitted and the drop pipe connected
direct to the dry return, then there would be a tendency for
the condensate in the dry return to back up instead of draining
into the boiler.
Why?
Ans. Because the pressure in the drip pipe at P, is greater
than the pressure in the dry return.
÷

RIGHT WAY
O
Toy
BY PASS
WRONG WAY

Figs. 6 and 7.-Right and wrong methods of connecting main to riser.
How should the risers be connected to the steam mains?
Ans. By 45° elbows.
Why?
Ans. So that the condensate will drain along the metal of
the pipe and fittings instead of dripping directly into the steam
which would tend to saturate and cool the steam.
822
Steam Heating Systems
Where a riser is connected direct to a drip pipe, how
should it be connected to the main?
Ans. By a 45° elbow, as in figs. 3 and 5.
How are water pockets avoided in reducing the size of
mains?
Ans. By the use of eccentric fittings.

WATER
I
NOTE HOW AREA IS REDUCED
WATER

Figs. 8 to 10.—Faulty piping methods. Fig. 8 shows a water pocket formed
because of lack of pitch, and fig. 9, another pocket formed by sag in pipe.
These pockets reduce the area available for the flow of steam with resulting
loss in efficiency. Fig. 10 shows a water pocket formed by reducing without
using an eccentric fitting.
What is an eccentric fitting?
Ans. A reducing fitting with the axes of the two outlets offset
so that the openings are flush with each other on the lower side.
Steam Heating Systems
823
Why should water pockets be avoided?
Ans. Because a sudden rush of steam occasioned by opening
a radiator might take up the water and project it with great
velocity and force against any turn in the direction of the main,
this effect being known as water hammer.

WATER POCKET
EFFECT
3
Figs. 11 and 12.-"Water hammer" caused by using ordinary fittings on mains
instead of eccentric fittings. In some instances (especially on long lines), a
sudden rush of steam through the pipe will hurl the water against the elbow
at the end with such violence as to fracture it, producing the same effect as
though the fitting were struck a violent blow with a hammer.
HAND
What trouble is sometimes encountered with radiators
located at elevations near the level of the water in the
boiler and why?
Ans. On long lines where there is considerable reduction of
pressure, the water sometimes backs up into the radiator, thus
interfering with its operation.
824
Steam Heating Systems
How may radiators be operated at elevations below the
water level in the boiler?
Ans. By means of a steam loop.

PITCH
FITTING
ho
RIGHT WAY
NO PITCH
DRUNKEN THREAD
FITTING
WITHOUT
PITCH
VERY LITTLE METAL HERE
WRONG WAY
PITCH

PITCH
Figs. 13 and 14.-Right and wrong way of making up coils and lines where
pitch is required for drainage. In first class work, "pitch fittings" are used to
secure the proper inclination of a pipe, but on the usual botch job, an ordinary
fitting is used and a "drunken thread" cut on the pipe. Evidently such method
of threading not only gives a poor joint, but one which because of the deep
cut on one side of the pipe is liable to leak in time by eating away of the
thin metal due to corrosion. On heating jobs such work should be rejected.
Describe the one pipe overhead system.
Ans. It consists of a riser or up flow pipe carried to the attic.
or highest point, forming a central riser for all the radiators.
It branches in the attic to the drips or down flow supply pipes
which serve the various radiators.
This system is well adapted to tall buildings.
Steam Heating Systems
825

LBS.
8
4 LBS.
DRIP I
2.3 FT
3 LBS.-
WATER LEVEL
IN BOILER
+
DRIP 2
46 FT.
2 LBS.
DRIP 3
6.9FT
WATER BOUND M
IL.B.T
DRIP 4
Fig. 15.-Water "backing up" in radiator on end of long line. Owing to pipe friction there is a gradual reduc-
tion of pressure in the main from the boiler to the end of the line, the water rising in the return pipes to gradu-
ally increasing elevations as L, A, R, F, to balance these pressure differences, the pressure difference being
so great at radiator M, as to bring the water level F, in the return pipe high enough to partially flood the
radiator. Hence, on the pressure differences at a remote point will depend the height at which the radiator
must be placed to avoid this trouble. Water levels in return pipes (to save space) are not to scale.
826
Steam Heating Systems


DROP OR DOWN FLOW PIPE
Sir
BRANCH
PANG
APAN
7
WATER LEVEL
IN BOILER
BOILER
WET RETURN
RISER OR UP FLOW PIPE
*
▼
Ans. In this system the
steam main is conveniently
(for rectangular buildings)
carried entirely around the
basement, pitching from a
high port above the boiler
100%
to low point at boiler drip
pipe. Risers are tapped from
the main at various points
to serve the radiators. In
the main, condensate drains
in the same direction as the
steam flow.
**
ごま
​
How does the piping com-
pare with the one pipe re-
lief system?
(
Ans. Since there is no re-
I
turn pipe, the circuit ar-
rangement is less expensive
to install.
Fig. 16.—So called "one-pipe” overhead system as installed in tall buildings.
Its features are uniflow of steam and condensation, which permits the use of
smaller pipes.
Steam Heating Systems
827
1
Describe the one pipe divided circuit system.
Ans. It is similar to the one pipe circuit system except that

RISER
¿
GOOSE NECK
UPPER RADIATOR
(CONDENSER)
STEAM
LOOP
DROP LEG
MAGINATION
BANANAAAAAAAMUULJ
ᎠᏑ
D
WATER LEVEL IN DROP LEG
BOILER
CHECK
VALVE
ZA
••
·
WATER
LEVEL
IN BOILER
LOWER
RADIATOR
Fig. 17.-Steam loop method of operating radiator placed below level of water
in boiler. In the steam loop the condenser element may consist of a pipe radiator
placed on floor above boiler. The liberal condensing surface thus provided
will render the loop very active in removing the condensation and at the same
time the heat radiated from the condenser is utilized in heating. The drop leg
is provided with a drain cock D, and the connection to boiler, with a check
valve. To start the system, turn on steam at the boiler and open D, until
steam appears. The condensation of steam in the condenser (upper radiator)
will cause a rapid circulation in the riser, carrying with it the condensation
from the radiator, which, in passing over the goose neck, cannot return, but
must gravitate through the upper radiator and drop leg past the check valve
and into the boiler. The pipe at the bottom of the main riser which acts as a
receiver for the condensate from the lower radiator, should be one or two
sizes larger than the pipe in the main riser.
828
Steam Heating Systems
CONSIDERABE PITCH
HIGH POINT,
DOWN
DOWN CIRCUIT WITH,
CONSIDERABLE PITCH
WATER LEVEL
IN BOILER
BOILER
DOWN
LOW POINT
DOWN
Fig. 18.-One-pipe circuit system. Since there is no relief, the condensation must traverse the entire circuit of
the steam main, hence it must be given considerable pitch. It is not necessary that the pitch be uniform but, as
must be evident, it should increase after each riser tap. Where there is little head room this will prove the more
efficient arrangement. The diagram shows the general features of the system.

Steam Heating Systems
829

1 DIVIDED
CONSIDERABLE PITCH
ROILER-
HIGH POINT
CIRCUIT AUTOMATIC
AIR VENTS
A
L
LOW
POINT
UOTUVAISTARIMĄ,
CONSIDERABLE PITCH
NOT LESS THAN 14 INS.
WATER LEVEL
IN BOILER
Fig. 19.-One pipe divided circuit system. Suitable for long buildings with boiler near the center. Since two
paths are offered for the steam to the risers, evidently the size of the main can be less than where the entire
flow passes through a single line; this then is a saving in installation. Moreover, for unequal distribution of the
radiation, the main can be proportioned accordingly, reducing the cost of piping to a minimum. Automatic
air vents should be placed at the end of each arm, as shown.
830
Steam Heating Systems

WATER LEVEL
IN BOILER
BOILER
MAIN
BUILDING
HIGH
POINT
CIRCUIT
[HUMUUR) BAMIRARMIN
HIGH
POINTI
VENT
SLES
BAGAY ANSHUAPAHOO (UNLA
WING
LOOP
LOW POINT
Fig. 20.—One-pipe circuit system with loop suitable for L-shape buildings, the circuit serving the main building,
and the loop, the wing. There are two high points in the steam main piping, thus both circuit and loop may
have ample pitch (which is essential for proper drainage), without undue head room. The circuit leads directly
to the boiler, but a return is placed between the end of the boiler and loop. Both circuit and loop should be
provided with an automatic air valve as shown. For ideal conditions the pitch of both circuit and loop should
be increased at each riser connection.

Steam Heating Systems
831
Scaun
come
ercula
STAY TUBE
(STEAM INSIDE)
SUPPLY HEADER
SONIC BER
RETURN HEADER
BBS
四
​Fig. 21.--Heater element as used with vertical shaft propeller fan. It consists of supply and return headers,
connecting tubes, heat dissipating fins and stay tube. The heating element is constructed of copper or copper
alloy. Each tube is provided with a bend to absorb the difference in expansion and contraction of each
tube. When provision for unequal expansion and contraction is made in a heating element, such as the bends
in the tubes, there is a possibility for the supply and return headers to be forced out of their correct positions
by expansion and contraction of the piping. However, if an external rigid member be used to keep the
headers of the heating element in their natural relative positions, the bends in the tubes are required to
absorb all the expansion and contraction of the heating element due to its temperature changes, instead of
just the difference in expansion and contraction between the individual tubes.
832
Steam Heating Systems
there is a T at the high point, giving a circuit on each side,
the main coming together at the low point and draining into
a common drip pipe.
This system is adapted to long buildings.
What should be placed at the ends of each circuit?
Ans. Automatic air vents.
Describe the one pipe circuit system with loop.
Ans. In this system there will be two high points; one at the
beginning of the loop, thus giving ample margin above the
boiler water line for liberal pitch in both the circuit and loop.
This system is adapted for an L shaped building, the loop serving
the L wing.
Describe the two pipe system.
Ans. In this system separate pipes are provided for the steam
and condensate, hence they may be of smaller size than where
a single pipe must take care of both steam and condensate.
Any arrangement of the steam and return main, such as the relief
circuit, divided circuit, etc., may be adopted to suit the requirements
of the building. Risers are connected to the steam main at suitable
points to serve the radiators, and down flow or drip pipes connect the
radiator outlets with the return main, as shown in fig. 3.
So Called Vapor Systems
("Atmospheric Systems")
What may be said with respect to manufacturers trade
talk relating to these systems?
Ans. If manufacturers of special steam heating systems work-
ing at atmospheric, or less than atmospheric pressure, would
1
Hot Water Heating
833
stop trying to appear learned by using such studied terms as
fractional control, modulation, thermo-seal, vapor, syphon, etc.,
etc., in describing their apparatus, and get down to plain
English, so as not to mystify the ordinary public, their cus-
tomers would no doubt be more enlightened and more numerous.
What is the meaning of the term vapor?
Ans. It simply means steam at approximately atmospheric
pressure.
What do you understand about the terms low pressure,
vapor and vacuum?
Ans. They are merely relative terms.
What do they mean?
Ans. Low pressure, 1 to 5 lbs.; vapor, 1 to 5 ounces; vacuum,
any pressure below atmospheric, all approximate.
What should be understood about the term atmospheric?
Ans. It is a convenient term for a pressure of a few ounces
above atmospheric, carried in the boiler or sufficient to over-
come the frictional resistance of the piping and since the return
connection of the radiators is open to atmosphere, it can be
understood that the success of the system depends upon the
proper working of the automatic damper in keeping the boiler
pressure within proper limits.
Describe one method of automatic damper regulation.
Ans. The dampers are controlled by a float working in a
float chamber, as in fig. 22, in communication with the water
space in the boiler. When the pressure in the boiler is the same
as that of the atmosphere, that is zero gauge pressure, the water
level in the float chamber is the same as that in the boiler. In
834
Steam Heating Systems

AIR AND
CONDENSATION
BOILER
PRESSURE IN
OUNCES PER 15-
SQ IN
A
B
FLOAT
FLOAT
CHAMBER
SLIGHTLY OPEN
INDEX
DAMPER
Dina.
---
DAMPER
STEAM
HALF
OPEN
STEAM
WIDE
OPEN
BOILER
아
​WATER LEVEL IN FLOAT CHAMBER
WATER LEVEL IN BOILER.
D
STEAM MAIN
AIR AND CONDENSATION-
E
WET RETURN
PESCA
VENT
STEAM
HIHIHIHIHIH
AIR
CONDENSATION
PLA LA QUE MESINSA DE LESEADUS KE KUPAGKAK
Fig. 22.-Atmospheric pressure or so called vapor system. Pressure at boiler one to five ounces or enough to
overcome the frictional resistance of the piping system; pressure at vent zero gauge or atmospheric. In
operation steam is maintained at about five ounces pressure in the boiler by the action of the automatic
damper regulator. The amount of heat desired at the radiators is regulated by the degree of opening of the
supply valve. Steam enters at the top of the radiator and pushes out the air through the outlet connection
which is open to the atmosphere. The condensation returns to the boiler by gravity. This system has the
advantage of heat adjustment at the radiator, but the devitalizing effect in the air is somewhat greater than
in the vacuum systems because the steam entering the radiators is at a higher temperature than the steam of
lower pressure in the vacuum system. It is, however, simple..
Steam Heating Systems
835
generating steam as the pressure increases, the water level in
the boiler is forced downward which causes the level in the
float chamber to rise until the pressure due to the difference
of water levels, balances that in the boiler. The float in rising,
since it is connected by pulleys and chains to the dampers,
closes the ash pit damper and opens the stack damper, thus
checking the draught and prevents the further increase of steam
pressure.
How is steam distributed to the radiators in the atmo-
spheric or vapor system?
Ans. Through the usual risers which, however, with this sys-
tem are connected to the radiators at the top, the condensate
and air passing off through a pipe connected to the bottom
of the radiator.
Why is it so connected?
Ans. Because steam is lighter than air, hence, when admitted
it floats on top of the air, thus driving the latter through the
lower connection.
What is the chief feature of the atmospheric system?
Ans. The amount of heat given off by each radiator may be
regulated by the steam valve (so called fractional control),
modulation valve and what not.
What is the object sought in the combined atmospheric
pressure and vacuum system?
Ans. It is to avoid devitalizing the air by using steam in
the radiators at pressures less than atmospheric.
Why?
19
836
Steam Heating Systems
RISER
4
DIAPHRAGM
AIR AND CONDENSATION
RISER
STEAM MAIN
R
SPRING
THERMOSTATIC
VALYE
DIAPHRAGM
VALVE
0000
F VENT
'FLOAT VALVE
FLOAT
Fig. 23. Combined atmospheric pressure and vacuum. Pressure in the boiler is obtained from one to five
ounces above atmospheric pressure, which is needed to operate the diaphragm regulator until air is expelled
and the complete system filled, it being then "throttled" by the radiator supply valves while giving the desired
vacuum in the radiators. In operation, when steam is raised in the boiler it passes through the steam main,
risers and supply valves to the radiators. The proper working of the system is obtained by an automatic
device or trap which closes against the pressures of either steam or water and allows air to pass out, but not
return. This device, as shown, consists of three elements: diaphragm valve L, float valve A, and thermostatic
valve F. There is a connection R, from the supply pipe or pressure side of the boiler to the diaphragm and
when there is no pressure in the boiler this valve is held shut by a spring. When the fire is started and the
air in the boiler is expanded, the diaphragm is inflated and opens the vacuum valve, making a direct opening
through valves A and F (which under this condition are also open) to the atmosphere. The valve L, remains
open as long as there is a fraction of an ounce pressure on the boiler. Now, as steam forms and passes
through the system it drives all the air out through the three open valves, L, A, F, but when the steam on its
return from the system reaches the thermostatic valve F, the heat causes it to expand and close, thus the
system is filled with steam only. The vacuum is now obtained on the principle that the steam admitted into
the radiators condenses, while transmitting its heat through the radiator and shrinks considerably (each cu.
ft. of steam being approximately reduced in volume to 1 cu. in.). If by too much throttling of the steam
supply to the radiators, the vacuum should become strong enough to draw up water in the return pipe too
high, the float rises and closes valve A, remaining closed until the water recedes, then it opens allowing
valve F, to expel any air that may be in the system and the process repeats itself automatically.

Steam Heating Systems
837
Ans. It reduces the temperature to which the metal of the
radiator is heated.
+
Give an example.
Ans. For instance the temperature of steam at atmospheric
pressure is 212° Fahr. and at say 5 lbs. absolute pressure which
corresponds to a 19.7 inch vacuum it is only 162° Fahr.
How is this vacuum obtained when the pressure in the
boiler is maintained at from one to five ounces above
atmospheric pressure, which is needed to operate the
damper regulator?
Ans. It is throttled by the radiator supply valves to give
the desired vacuum in the radiators.
What is a natural vacuum system?
Ans. Any standard one or two pipe steam system may be
converted into a natural vacuum system by replacing the ordi-
nary air valve by a “mercury seal" or connecting thermostatic
valves to the radiator return outlet on radiators and providing
a damper regulator to the boiler adapted to vacuum working.
What is a mechanical vacuum system?
Ans. The term mechanical vacuum system is used to indicate
vacuum systems in which an ejector or pump is used to main-
tain the vacuum.
What do you understand by the term exhaust steam
heating?
Ans. It relates to the source of the steam rather than to its
distribution.
After the exhaust steam enters the heating system its action is no
different from live steam taken from a heating boiler, it being adapted
to both low pressure and vacuum systems.
838
Steam Heating Systems

FIG. 24.-Exhaust steam heating
system with fractional valve control
and automatic make up. In opera-
tion, exhaust steam normally passes
via branch A, to radiator, the con-
densate being pumped by air pump via
D, through the receiver from whence it
is returned through heater to boiler
by feed pump E. If the demand
exceed the supply of exhaust steam
the pressure of regulating valve
diaphragm will decrease and weight
C, will open valve admitting live
"make up steam to the heating
system until the supply is again
equal to the demand.
Again if the supply of
exhaust steam exceed
the demand (radiators
turned off) the pressure
will increase and open
back pressure valve B,
allowing exhaust,
escape to atmosphere.
to
с
BOILER
ENGINE
TO ATMOSPHERE
BACK PRESSURE
VALVE
PRESSURE REGULATING
ACCUMULATOR
LIVE STEAM
OIL SEPARATOR
FEED TO
BOILER
HEATER
EXHAUST FROM PUMPS
CONDENSATION
*
OIL TRAP
RETAINER VALVES
E
RISER
FEED PUMP
THERMOSTATIC
VALVE
RISER
VENT
RECEIVER
MAKE UP VALVE
D
WET AIR
PUMP
WATER FROM STREET MAIN
Steam Heating Systems
839
THERMOSTAT
TYPE T2058
T
FLOOR
TIME SWITCH
FORM KAH 12
24V.60C.
LOW PRESSURE
STEAM HEATING
BOILER
T49Q
i
5 WIRES
TEST
CONNECTION
BURNER
TRANS
20 WATTS
20 VOLTS
3 WIRES
MVİNCAAG
of
TRANS. 35 WATTS
FURNISHED BY W.W. & CO.
Ž
SERVICE
110V. 60 C

PRESSURE DIFFERENTIAL
CONTROLLER
3 WIRES
TEST.
CONNEC
TION
CONNECT
TO RETURN
1000°
I PIPE INSERT TO
PASS IDIA, BULB
EH-10
CONTROL CABINET
CONNECTIONS FOR VACUUM SYSTEM
RELAY
R-32A
CAPILLARY TUBE
25' LONG
OUTDOOR THERMOSTAT
LOCATE IN ACCESSIBLE
POSITION. PREFERABLY ON
NORTH WALL OF BUILDING.
DO NOT PLACE NEAR
WARM CURRENTS OF AIR.
SERVICE
110V.60C.
20 WATTS
NOTES
ALL WIRING AND COMPLETE
INSTALLATION TO BE MADE IN ACCORD-
ANCE WITH LOCAL ELECTRICAL CODES
AND ELECTRICAL SPECIFICATIONS.
ALL WIRING TO CARRY 24V. UNLESS
OTHERWISE NOTED.
NOTE.
ELECTRICAL CONTRACTOR TO FURN-
ISH NECESSARY CUTOUTS AND SERVICE
SWITCHES.
PRESSURE
CONTROLLER
TEST
CONNECTION
G.V.
T
CONNECTION FOR
OPEN RETURN SYSTEM
DOTTED LINES INDICATE WIRING
IN ACCORDANCE WITH BURNER
MANUFACTURERS REQUIREMENTS,
1
Fig. 25.-General arrangement of Moderator system controlling burner to steam
boiler. This system was designed chiefly for the small and medium sized build-
ing. Control is accomplished by varying the length of on intervals during
which steam is delivered to radiators. The latter are equipped with metering
orifices. An outdoor thermostat is attached to the control cabinet by capillary
tubing. Attachments are: clock for automatic turn-on at heating up rate, return
to normal operation, and night shut-off. Indoor thermostat, with or without
clock, is optional.
840
Steam Heating Systems

SERVICE
110V.600.
TRANS, 100 WATTS
FURNISHED BY
ww.& co
OPER
OPERATING SCHEDULE
CARD
JUMPERS
MAN VALVE
SWITCH
BW!!
CONNECT WIRE
E-IN CONTROL
ITO TERMINAL
VALVE MOTOR AS SHOWN
RQ_RELAY CABINET
JUMPER
SP HYLO STEAM
VARIATOR CABINET
ELÉCTRICAL
CONDUIT TO
RQ RELAY
CABINET 8
VALVE MOTOR
E-IN CONTROL
VALVE
32
OUTDOOR TEMPERATURE
DIAL
PILOT LIGHT
GATE
VALVES J
a
AT LEAST
PIPE DIAM'S
GATE
VALVES
FLOOR LINE
·STEAM MAIN
RETURN
RISER
SUPPLY
RISER
BHO
电
​RETURN
MAIN
Fig. 26.-General arrangement of Hylo variator with control valve in steam
main. A central control of the graduated, continuous flow type which varies
steam supply to the entire heating system in accordance with changes in out-
door temperature. Adjustment of control dial causes motor to position control
valve in steam main. Ordinary pressure variations in supply and return mains
are compensated for automatically by sensitive bellows. Adjustment of the
temperature dial may be made by reference to thermometer located outdoors,
or remote reading thermometer may be mounted near control cabinet. Time
switch for automatic turn-on and shut-off, or indoor thermostat for automatic
overheat limit shut-off are optional. Applicable to two-pipe orificed systems,
either open return or vacuum, using low pressure steam, from any source. May
also be applied with minor modifications to direct control modulating stokers,
motor operated draft dampers on hand fired coal boilers, or blowers.
Steam Heating Systems
841
GRADE
What are the chief differences?
Ans. The provision for delivering the steam from the engine
to the heating system free from oil and at constant pressure
and for returning the condensate to the boiler at high pressure.
Fig. 24 shows the essentials of an exhaust steam heating system.


WATER
LINE
BRASS
PIPE
NIPPLE
FLOOR
ORIFICE
UNION
ELBOW
FLOOR
1
ORIFICE
WATER
LINE
GRADE
WATER
LINE
GRADE
FLOOR
-GRADE
BENT
COPPER TUBE
VALVE
NIPPLE
CUP
ORIFICE
REST
— 1 d. fum ciuda
ORIFICE
EXTENDED
UNION
NIPPLE


WATER
LINE
Figs. 27 to 30.-Orifice fittings as used for concealed radiation. Fig. 27 shows
a standard cup-type orifice in a union elbow applied to cabinet radiation
with end connections when supply valve is located below basement ceiling;
figs. 28 and 29, method of orificing concealed radiation having bottom
connections; fig. 28, the orifice is furnished in an extended union nipple;
fig. 29, in an extended brass pipe nipple, fig. 30, a special bent tube orifice
used with concealed radiators having off-set type headers.
842
Steam Heating Systems
WEBSTER SUPPLY VALVE
Die
SUPPLY RISER.
RETURN RISER
GATE
VALVE
WEBSTER 32 COMPOUND GAUGES
HIGH
VACUUM
01-01-1991
Fig. 31.-Method of connecting radiator trap and supply valve with female
inlet and outlet to a standard radiator using right and left hand nipple.
LOW
VACUUM
04:0
WEBSTER HYLO
ĮVACUUM CONTROLLER
CATE
VALVE
Hert
RIGHT AND LEFT HAND NIPPLE

IOL
IGATE VÁLVE
CONNECT TO HIGH
VACUUM RETURN
ECCENTRIC BUSHING
GATE
VALVE
BY PASS
RIGHT AND LEFT HAND
NIPPLE
WEBSTER
SERIES
TRAP
CONNECT TO LOW
VACUUM RETURN
WEBSTER RETURN
TRAP
169
FLOOR

GATE
VALVE
WEBSTER
DIRT STRAINER
Fig. 32. Method of connecting Hylo controller and related equipment. Indi-
vidual buildings of a group of individual sections of a building served by a
single source of vacuum may require different degrees of vacuum for proper
steam circulation. Use of controllers and related equipment provides means
to maintain different yet constant degrees of vacuum at various points through-
out the heating system. Once adjusted it is not necessary to change the
controller as it automatically maintains proper circulation.
Steam Heating Systems
843

SUPPORT ARMS
STAY
TUBE
FINS
!
⠀⠀ ---⠀⠀⠀----------
C
MOTOR
Fig. 33.-Vertical shaft propeller fan hijet type heater.
LO
ADJUSTABLE DISCHARGE
FAN
LOOPS
844
Steam Heating Systems
Limit
Thermostat
in unground.
ed line
(Optional)
Trap
• NOTE·
Wiring for D.C.
& 1000 series
single phase
are similar.
•
Supply
•hijet heater
-Return
Electric room thermo-
stat to start & stop
motor (Install in un-
grounded line)
Return
3 phase main
line.
·Supply
Special switch for two or
three speed motors. Use
ordinary snap, switch for
one speed motor.
Fig. 34.-Wiring of single phase motor with thermostatic control.
Fig. 35.-Wiring of three phase motor with thermostatic control.
hijet heater
Electric room thermostat
controlling magnetic, relay
to start and stop motor
Trap
-Limit therm.
ostat controll-
ing magnetic.
relay (Optional)
Magnetic
Relay
Switch & Fuses.


Steam Heating Systems
845

Return
Limit thermostat in
ungrounded line
(optional)
11
Supply
Trap
thermostatic
control unit
Fig. 36.-Wiring of single phase two speed motor with thermostatic control of
two speed operation.
NOTE.-Automatic Control. The temperature in any building equipped with
hijet heaters may be controlled manually or automatically. With manual operation,
the usual practice is to merely start and stop the motors to maintain the proper
temperature. The simplest method of automatic control is to use a thermostatic
electric switch to stop and start one or more motors as required. When the steam
or hot water supply is intermittent, it is advisable to make provision for stopping
the motor when the heating element cools, otherwise the unheated air circulated
by the fan may cause drafts. One way to accomplish this is to use a limiting ther-
mostat fastened to the return line from the heater arranged to stop the motor
when this pipe cools and to start it when the pipe again becomes hot. When
controlled in this way, the heater will not circulate unheated air.
NOTE. Thermostatic Control of 2-Speed Operation. When the room
temperature is below the temperature setting of the thermostat, the heater operates
at full speed until the room temperature is raised to within 2 degrees of the ther-
mostat setting. At that point, the heater motor is automatically switched to slow
speed and continues to so operate until the room temperature reaches the ther-
mostat setting, when the motor is shut off completely. As the room cools, the
reverse cycle takes place. During average, normal weather, once the room is
brought up to temperature, the heater operation would alternate between of and
slow speed, running at full speed only when greater heat delivery is required to
maintain desired room temperature. In the morning or after idle periods, the
heaters will automatically operate at full speed to quickly warm the room and
then continue on slow speed or be shut off, depending upon the room temperature
requirements,
53
846
Steam Heating Systems
What is an indirect heating system?
Ans. This is a combination of steam (or hot water) heating
and hot air heating, the object of the system being to secure
the advantage of steam (or hot water) as a heating medium and
avoid the disadvantages of these on the hot air furnace.
What is the essential feature of this system?
Ans. Fresh air from the outside is passed over a radiator
placed in an air duct or flue, the heat imparted to the air
causing a brisk circulation, thus fresh air is constantly entering
the room to be heated.
Hot Water Heating
847
CHAPTER 44
Hot Water Heating
Mention a feature of hot water heating.
Ans. The low working temperatures.

RETURN
FEED
TO SMALLEST
RADIATOR
TO LARGEST
RADIATOR

Fig. 1.-Best method of taking connection from the top of main flow and return
in hot water heating. A 45° elbow may be taken from the top if the head
room be limited. Steam connections should be taken off the main in the same
way.
Fig. 2. Proper method of taking off connections from a hot water riser on the
same floor, one being larger than the other.
Why?
Ans. It gives a mild heat, that is, does not devitilize the air
of its oxygen.
What is necessary for heat transmission in hot water
systems?
848
Hot Water Heating
Ans. There must be constant movement of the water from
the heater to the radiators and back again.
What is this called?
Ans. Circulation.
What is natural or thermo-circulation?
Ans. Circulation due to the difference in density or weight
of water at different temperatures.

MA
****

RETURN
=
FEED
TO UPFER FLOORS
Fig. 3.-Best method of taking hot water connections from the end of mains.
The end connections should turn up and the pipes run at the same level as
the pipes nearer the heater so as to give the last pipes the same advantage
as the others.
Fig. 4. How connections on hot water risers should be made so as to give all
the advantage to the lower floor. The tendency is for the hot water to flow to
the upper floors and means similar to the above are necessary to offset this
tendency.
Give an example.
Ans. One cu. ft. of water at 70° Fahr. weighs 62.3 lbs. and
at 212°, 59.82 lbs. representing a difference in weight of 62.3-
59.82 2.48 lbs. which is available to cause circulation as
shown in figs. 1 and 2.
Name the two basic hot water heating systems.
Ans. The one pipe and the two pipe systems as shown in
figs. 3 and 4 respectively.
Hot Water Heating
849
What is the essential part of the one pipe system?
Ans. The essential element of this system is distribution tees
for each radiator.
What is the object of these distribution tees?
Ans. They deflect part of the water from the main into the


RETURN
TO TRAP
OR PUMP
STEAM
FEED
CLEAN OUT PLUG
Figs. 5 and 6.—Water heater set up in connection with a storage tank. It can
be used in this way for exhaust or high pressure steam, and the water of con-
densation may be returned to a well by a trap, or taken to a pump governor,
provided the pump receiver do not carry pressure. The water of condensation
should drain freely from the tubes to get good results.
radiators while letting the balance flow through the main to
the next radiator.
Why is the system called one pipe system?
Ans. Because in the sense that one pipe serves both inlet and
outlet of each radiator.
850
Hot Water Heating

:
DOWN FLOW
I CU FT: OF WATER AT 70%
HEATER
I CU FT. OF WATER AT 212º
RISER
M
15pi
110953dlegellem
Figs. 7 and 8.-Motive force in natural circulation hot water heating system.
The question is often asked, "Why does the water circulate?" It is due to the
difference in density of water at different temperatures. Thus in fig. 8, if the
riser pipe hold say 1 cu. ft. of water at 212° its weight is 59.82 lbs., and
similarly if the return pipe hold 1 cu. ft. of water at 70° its weight is 62.31 lbs.
Thus the column of water in the return pipe is 62.31-59.82 = 2.49 lbs. heavier
than the column of water in the riser. This unbalanced weight forms a motive
force which causes the water to circulate through the system as indicated by the
arrows, and further portrayed by the effect of the unequal weights placed on
the beam scale, fig. 7.
=
Hot Water Heating
851
I
What must be provided in hot water systems?
Ans. Provision for expansion of the water as the temperature
rises.

L
H
48
2711:||
DISTRIBUTION
TEE
HEATER
F
1
Fig. 9.-So called one-pipe natural circulation hot water system. L is the
riser side and F the down flow side. The system consists of a vertical loop
which carries both the supply and return water of the radiators. Special dis-
tribution tees having an internal baffle tongue facilitate the circulation to and
from the radiators, this being shown in detail in fig. 10. No air vents on the
radiators are necessary.
852
Hot Water Heating
How is this taken care of?
Ans. By installing an expansion tank at the highest point as
shown in the illustration.
How does it work?
DISTRIBUTION TEE

BAFFLE
TONGUE
DISTRIBUTION
TEE
MAIN
Fig. 10.-Distribution tees connecting radiator to main of so called one pipe
system, shows baffle tongues which deflect part of the water from the main in
and out of the radiator while by passing the balance along the main.
Ans. As the water expands with rise of temperature the ex-
cess volume flows into the expansion tank.
Name another feature of the expansion tank.
Ans. The boiling point of the water may be increased by
Hot Water Heating
853
❤
elevating the expansion tank which increases the pressure.
Thus the water can be heated to a higher temperature without
generating steam which in turn causes the radiators to give off
more heat.

OVERHEAD
MAIN
DOWNFLOW
RISER
DOWNFLOW
Fig. 11.-Overhead system. It is considered by some as the best method of
piping. Although it is not adapted to all classes of buildings, there are many
such as apartments, stores, office buildings, hotels, etc., where the general
arrangement lends itself to this system. No air vents are necessary at any
point on the system, as the arrangement is such that all air works to the top
and passes off into the expansion tank.
854
Hot Water Heating
Name two kinds of expansion tank.
Ans. Open and closed.
What is the application of these types?
Ans. The open expansion tank is used on low pressure sys-
tems and the closed tank on high pressure systems.


KIMIHTO
ZERO GAUGE
14.7 LBS.
ABSOLUTE
60°F.
6.3 LBS. GAUGE
21 LBS.
ABSOLUTE
230°
HE
Figs. 12 and 13.-Application of closed expansion tank in hot water heating.
It permits heating the water above 212° Fahr. When cold, say at atmposheric
pressure and the furnace be started, the water may be heated to any proper
working temperature because the pressure is automatically adjusted to corre-
spond with the temperature. That is, steam will form and continue to form till
it reaches a pressure corresponding to the temperature, here taken at 230° Fahr.
Hot Water Heating
855
How does the closed expansion tank work?
Ans. The tank normally being partly filled with water, the
air in the tank above the water forms a cushion for increasing
pressure.
Describe the increase in pressure.
Ans. As the temperature of the water rises it expands and
flows into the tank, thus compressing the air and increasing the
pressure.
What is the relation between pressure and volume
changes of the air?
Ans. According to Boyles' law at constant temperature the
pressure of a gas varies inversely as its volume. Thus, when the
volume is reduced to half, the pressure is doubled.
.
What kind of pressure are we talking about?
Ans. Absolute pressure and once and for all in this case
absolute pressure-not gauge pressure.
After studying Chapter 1, do you remember what is
"absolute pressure"?
Ans. Yes. Absolute pressure is pressure measured above zero.
What is the application of absolute pressure?
Ans. It is used in all calculations relating to the expansion of
gases.
The author resorts to sledge hammer technique in trying to em-
phasize absolute pressure, because it is amazing how many people
not only haven't the slightest idea of what it is, but in some cases
never even heard of it.
"
856
Hot Water Heating

– EXPANSION TANK
--HEATER
Fig. 14.-Circuit two pipe natural circulation hot water system. A single main pipe is taken to a high point
under the basement ceiling and then pitched along its run as much as possible to the return inlet of the heater.
The risers are taken off the top of the main and the down flow pipes are tapped at the side with tangent
tees. Where the riser and return are very close together a special fitting is used, so arranged that the flow
to radiators leaves the top of the main and the return or down flow enter at the bottom. Air vents on the
radiators are necessary.
Hot Water Heating
857

I
THE GREATER THIS DISTANCE
THE MORE RAPID THE CIRCULATION
SM
M2
EXPANSION
TANK
F
CIRCULATION
BY PASS PIPE
HEATER
DOWN FLOW
→
Fig. 15.-Two-pipe natural circulation hot water system. In operation, after
the fire is started the temperature of the water in the heater rises, and expands;
this disturbs the equilibrium of the system, causing the colder and heavier
water in the down flow pipe to flow downward, pushing the warmer and lighter
water in the riser upward, thus starting circulation, a circulation by pass pipe
being provided to form a continuous path for the flowing water in case all the
radiators be shut off. The expansion of the water will cause it to rise in the
expansion tank from M to some higher level as S. Now if valves L and F, be
opened the water will flow through the radiators, where most of its heat is
absorbed in heating the rooms. This will increase the density of the water in
the down flow pipe, thus accelerating the circulation. Air vents on the radiator
are necessary. Because of this expansion it is necessary to leave the highest
point of a hot water system open to the atmosphere and provide at that point
an expansion tank for the variation in volume.
858
Hot Water Heating
What is the usual mistake made in making calculations
relating to expansion of gases, for instance the expansion
of steam?
Ans. They, in most cases, use gauge pressures instead of
absolute pressures and of course get ridiculous answers.
Describe the two pipe heating system.
Ans. In construction a single main pipe is taken to a high
point under the basement ceiling and then pitched along its run
as much as possible to the return inlet of the heater. The risers
are taken off the top of the main and the down flow pipes are
tapped at the side with tangent tees.
The essentials are clearly shown in fig. 15.
What pitch should be given to the loop main?
Ans. The loop circuit of extra large pipe should have a pitch
not less than one-half in. per 10 ft. run. More pitch would be
better.
:
:
Heating Calculations
859
CHAPTER 45
Heating Calculations
What is the first calculation in determining the size of
a heating plant?
Ans. An estimate of the loss of heat from the building.
How is this figured?
Ans. On a basis of B.t.u. lost per hour.
In what two ways is heat lost?
Ans. 1, By radiation, and 2, by convection.
How is heat lost by radiation?
Ans. It is transferred through walls, windows, etc.
How is heat lost by convection?
Ans. It is carried off by the movement of the air as it passes
out through the opening in the building.
813
How about the values given by various authorities for
heat loss for various materials?
Ans. Although they are found by experiment and agree
closely, the results sometimes vary quite widely due to the
quality of the workmanship.
860
Heating Calculations
Figuring Radiation
There are four basic units used in figuring radiation. In
figuring without tables average values are taken for the units
and they are:
1. Wall factor...
2. Contents factor.
3. Glass factor.
4. Radiation factor.
.32
.02
1.
240
By remembering these factors it is easy to figure radiation
for any temperature variation or condition.
What are these basic units or factors?
Ans. They represent the amount of heat (in B.t.u.) that will
pass through one sq. ft. of the material in one hour.
Thus .32 B.t.u. will pass through a sq. ft. of ordinary brick wall, or
through a wall where the average frame construction is used.
What is the unit .02?
Ans. The .02 is the fraction of a B.t.u. that is used in an hour
by a cu. ft. of the content volume of a room.
What is the unit 1?
Ans. The 1 is the B.t.u. that will in an hour pass through a
sq. ft. of glass.
What is the unit 240?
Ans. The 240 is the amount of heat in B.t.u. given off by
ordinary cast iron radiators per sq. ft. of heating surface per
hour under average conditions.
Upon what is the unit based?
Heating Calculations
861
Ans. Upon the facts that repeated tests have shown that
the amount of heat given off by ordinary cast iron radiators
per degree difference in temperature between the steam (or
water) in the radiator and the air surrounding same to be about
1.6 B.t.u. per sq. ft. of heating surface.
Taking this as a basic a steam radiator under 2½ lbs. pressure, cor-
responds approximately to 220° which is surrounded by air at 70°,
will give off under these conditions.
(220-70°) X 1.6 240° B.t.u.
that is

240 B.t.u.
per sq. ft. of heating surface per hour.
Why are the particular values here given adopted for cal-
culating radiation?
Ans. Of course the wall unit .32 varies for different kinds of
walls and the radiation factor 240 varies with different con-
ditions.
This is a simple and quick way of calculating radiation and is ap-
proximately accurate.
What allowances and additions should be made?
Ans. The usual allowances should be made for unusual ex-
posures, rooms with fire places, etc. They are common sense
allowances, however, and are not difficult to keep in mind.
Example in Figuring Radiation by the Simplified Method.
To find the radiation required by a room, the first step is to figure the
room in the regular way, that is, find its volume, the amount of exposed
wall and the amount of glass. The following example is given:
862
Heating Calculations
Example.-Figure the radiation required for the following room:
Size of room
14 ft. X 14 ft. X 9 ft.
60 sq. ft.
70° Fahr.
Square feet of glass (windows)
Required inside temperature
Walls exposed on two sides
Volume of room = 14 X 14 X 9
Two sides of room exposed
(14+14) × 9:
=
252 sq. ft.
Deducting glass exposures
252 - 60 192 sq. ft.
=
Temperature difference
inside temperature
70
=
outside temperature
(-10)
This means there will be a temperature difference of 80° between
the inside and outside of the room in coldest weather.
1764 cu. ft.
Calculation of B.t.u.
pe
192 X .32 X 80.
•
==
· 80° Fahr.
1. Volume of room.
This as calculated is 1764 cu. ft.
Accordingly to raise the temperature of the volume of the room 80°
1764 X .02 X 80....
2822.4
!
3. B.t.u. required for glass.
60
Square feet of glass
Accordingly
2. Exposed walls.
Net exposure as calculated is 192 sq. ft.
Accordingly
60 X 1 X 80:
+
..4915.2
4800
4. Total heat required.
Adding the three results just obtained the total heat required every
hour is
}
Heating Calculations
863
1. Volume.
2. Exposed walls.
3. Glass...
:
RULE.-Divide total radiation by 240
234
Total radiation.
3
714
10
5 42/4
6 15
7 | 1734
& 20
Selecting the Proper Radiation.-Remembering that 1
sq. ft. of radiator surface gives off 240 B.t.u. per hour, that is
for an ordinary cast iron radiator on a steam job:
Peerless Two-Column Radiators
For Steam and Water
21 52
22 55
23 572
24 60
12537.6 ÷ 240 =52.2 sq. ft.
Consulting the following table select the nearest size.
TABLE OF RADIATORS
Peerless Three-Column Radiators
For Steam and Water
25 62
26 65
27 674
28 70
29 72
30 75
31 77
32 80
SQUARE FEET
No.
32-in.
HEATING SURFACE—SQUAre Feet
HEATING SURFACE
No.
of ||Length 45-in. 38-in.
26-in. 23-in. 20-in. of Length 45-in. 38-in. 32-m. 26-in. 22-in. 16-12
Sec-215 In Height Height Height Height Height Height | Sec- | 2% in. | Height | Height|| Height Height Height Height
tions per Sec. 5 Sq.Ft. 4 Sq.Ft. 34 Sq.Ft 234 Sq.Ft. 24 Sq.Ft. 2 Sq.Ft tions per Sec. 6 sq. ft. 5 sq. ft. 494 sq. ft.37, 19. ft.3 sq. ft.27% 19 ft.
per Sec. per Sec. per Sec. per Sec. per Sec. per See
per Sec. per Sec. per Sec. per Sec. per Sec. per Sec.
02838392:
35
40
9 2234 45
10
25
50
11
27/2
12 30
13 324
.14 35
15 37%
16 40
17 42
18 45
19 | 47
20 50
10
15
25
02022
8
12
16
24
28
32
631
10
131
167
20
23
263
30
331/
36
40
36
40
55
44
60 48
65 52
70 56
75 60
80 64
85
68
90
72
95
76
6311
100
80
663
105 84 70
1.10 88 731
115 92 7673
120 96 80
125 100 83
130 104 86
135 108
140 112
90
931/1
145 116 96
150 120
155 124
160 128
43
46/
50
531/
56/1
60
100
103
106
53/1
8
1036
13
16
18
213
24
2631
29
32
•
34%
37
40
42
45%
48
50%
531
56
58/1
611/
64
66
69
72
7435
7715
80
823
85
4/5
7.
911
113
14
TORONTUR°~~~~O~1H397
4
6
8
10.
12.
16% 14
183
16
18
20
23456789
STO22;
22
71½
10
123½
17½
8 † 20
2828
2216
20+00
271
30
12
·
18
24
30
36
42
48
Oz8383378383°283
.4800
12537.6
21
23
10 25
11
60
66
25.
28
24
12
72
13
32½
78
482
28
14
52
301 26
323%
35
3735
15
30
32
56
35
84
371½ 90
40
96
17 42% 102
67%
16
72
60
63/4
67
3935 34
42
4414
4671
36
38
10890-
114
7112
75
78%
49
22
761½
18. 45
81
19 4712
95 852
20 50 120 100.90
21 5234 126 105 94½
31/
55 132 110 99
531 46 23 37½ 138 115 103½
56
48
24
60 144 120 108.
384 50 25 6216 150 125
112½ 93
603 52 26 65 156
971
63
54
27 67
67162
101
56
1 168
105
723½ 174
82
864
90
130
117
65
70
67/1 58 29
108
60 30 75
180
70
721 62
74
31
186
150
155
192 160
77%
64 32 80
135
140
145
2822.4 B.t.u.
4915.2
66
9
131½
18
2212
27
311/4
36
40
45
4914
54
58½
63
121
126
130½
135
139%
144
C
11/2
113
15
18
222
26%
30
3322
3736
411/2
尖
​112/2
1164
120
**~~*~*~83×A~~*KMK838ONKZZI5822
66

21
36
.75
6%
131
154
18
201
2216
24
27
29¼
31
33
36
381
401
42%
45
47%
493
511
54
561
58
60
63
65
6712
691/
72
-
In the code following on "How to Figure Radiation," the method
of calculation is taken up in greater detail, and represents a standard
as adopted by the Institute of Boiler & Radiator Mfgs., here repro-
duced by special permission. It should be noted that page 2 of the Code,
which is a blank has been omitted to save space. It should be further
noted that the pages of the Code are numbered at the bottom 1 to 20.
These numbers correspond with our page numbers 864 to 882 inclusive.

How to
Figure Radiation
FX
D
The author is indebted to the Institute of
Boiler and Radiator Manufacturers for per
mission to reproduce this Code on How to
Figure Radiation.
Note. This Code is revised from time to
time and the latest revision can be obtained
from the Institute.
Copyrighted 1939 by
THE INSTITUTE OF BOILER & RADIATOR MFRS.
60 EAST 42nd STREET
NEW YORK CITY
How to Figure Radiation
Because of the wide variation in heat loss through different kinds of
building material and the different types of construction in common use,
we believe the British Thermal Unit (B.t.u.) method for calculating heat
loss to be the correct method and therefore will be the basis for determining
the amount of radiation required.
The information contained herein is intended primarily for use in
connection with residential type of construction.
The BTU Method of Figuring Radiation
Table 1. shows coefficients of heat transmission per degree temperature
difference between inside and outside 'for building materials and types of
construction most commonly used in small residences, and the factor for
air changes per cubic foot per degree temperature difference. For complete
table of coefficients refer to A.S.H. & V. E. Guide.
To compute the amount of radiation for a given space all heat losing
factors such as walls, ceiling, floor, windows, doors and air change must
be considered.
Example for use of the B.T.U. method-
Suppose we have a room 12' x 20' with 9' ceiling with one end
wall and one side wall exposed (lath and plaster, studding, sheathing,
and siding) four windows single glass cach 3′ x 5', non weather-
stripped, wood lath and plaster ceiling, single floor above exposed to
unheated attic, air change based on crack loss method, no floor loss
considered. Room to be heated to 70° inside when it is zero outside.
How much radiation would be required?
First: Establish temperature difference between inside and outside
for which you are making calculations, which in this case is 70° except
for the ceiling which is 35° (see note next multiply the coefficient
corresponding to the type of construction used, as shown in Table 1.,
to determine the rate of transmission per sq. ft. per hour.
Rate of transmission for wall. The coefficient for the wall, as
described above, is .25, which multiplied by 70° temperature difference
equals 17.5 B.t.u. loss per sq. ft. per hour.
3-
HOW
TO FIGURE RADIATION
Rate of transmission for single glass is 1.13, which multiplied by
70°, the temperature difference, equals 79 B.t.u. loss per sq. ft: per hour.
Rate of transmission for ceiling. The coefficient for ceiling, lath
and plastered single floor above, is .28 which multiplied by 35, the
temperature difference, equals 9.8 B.t.u. loss per sq. ft. per hour.
The factor for air change is .0181, which multiplied by 70, the
temperature difference, equals 1.267 B.t.u. required to heat each cubic
foot of air from 0° to 70°.
The next step is to apply these rates of transmission to the
amount of exposed wall, glass surface, ceiling and cubic contents
as follows:
32 x 9 equals 288 sq. ft. of exposed wall, less sq. ft. of
glass, equals 228, which multiplied by 17.5 (the rate of
transmission per sq. ft.) equals
4 windows 3 x 5 equals 60 sq. ft. of glass, which multi-
plied by 79 (the rate of transmission per sq. ft.) equals.... 4740 B.t.u.
240 sq. ft. of ceiling, which multiplied by 9.8 (the rate
of transmission per sq. ft.) equals
The infiltration loss with a wind velocity of 15 m.p.h.
equals 40 cu. ft. per linear ft. of crack for windows
(with three windows on one side of this room.) We
compute the infiltration loss for three windows only.
Therefore, by multiplying 3 x 19 x 40 equals 2280 cu.
ft. multiplied by 1.267, the B.t.u. required to heat one
cu. ft. of air from 0° to 70° F. equals
………………….
Matte
………………
PORTALU KONDOMINION EDO DE CONE AD a é at a
Total heat loss per hour
Next divide this total heat loss by 240, the number of
B.t.u. given off by one sq. ft. of Standard Steam Radiation.
13970 divided by 240 equals 58.2 sq. ft. of Steam Radia-
tion; or 150, the number of B.t.u. given off by one sq. ft.
of Standard Warm Water Radiation equals 93 sq. ft. of
Warm Water Radiation; the amount required to heat this
room.
– 4 –
J
ANA…………………………… …….. I DO AND……………
PRODUKANDUNG
3990 B.t.u.
2352 B.t.u.
2888 B.t.u.
13970 B.t.u.
Realizing that the B.t.u. method involves complicated calculations,
we submit a simplified divisor method to be used for checking plans
and specifications.
HOW TO
FIGURE RADIATION
İ
The Divisor Method
Table 1 gives divisors for determining the amount of standard steam
and warm water radiation for different types of construction for 70° F.
inside, 0° F. outside, and tables of correction factors, (Tables 2, 3, 4, 5,
and ) for other inside and outside temperatures. These divisors and
correction factors will give substantially the same result as the B.t.u.
method of heat transmission calculations except for air change which will
show slightly more radiation than for the crack loss method.
Table 1
Coefficients are expressed in B.t.u. per sq. ft. of heat losing surface per
degree F. difference between air at the two sides and are based on wind
velocities of 15 m.p.h. If higher wind velocities are to be considered, see
A.S.H. & V.E. Guide for additional amount of radiation required.
Divisors are for Standard Steam and Warm Water Radiation under
Standard Conditions of zero outside, 70 degrees F. inside, except ceilings.
(See note.)
It is considered good engineering practice to add 10% to amount of
radiation arrived at by either method, in rooms on windward side of
building.
Walls
Frame and Miscellaneous Construction
………………………
Uninsulated
Lath and Plaster, Studding, Sheathing
and Siding or Shingles
Lath and Plaster, Studding, Sheathing
with 4" Brick Veneer
Lath and Plaster, Studding and Siding
or Shingles
Studding with Lath and Plaster Two Sides
Studding with Lath and Plaster One Side...
Studding, Sheathing and Siding
Studding and Sheathing or Siding
* Asterisk indicates coefficients and divisors most commonly used.
•
NONOOD DONA
CALORIES AND DEN B
A gu à à à pre
- - - - -…………A
- - - - SO I COU
Warm
B.t.u. Loss Steam Water
Coefficients Divisors Divisors
.25
.25
.30
.36
.65
.33
.70
14*
14*
11
୨
ܡ
5.3
10
S
8.5*
8.5*
7
6
3.3
6
3
- 5-
HOW TO FIGURE RADIATION
Insulated
Lath and Plaster, Studding, Sheathing and
Siding or Shingles with 3" Rock
Wool Fill
Lath and Plaster, Studding, Sheathing and
4" Brick Veneer with 35%" Rock
Wool Fill
Plaster on 1/2" Rigid Insulation, Studding,
Sheathing and Siding or Shingles........
Plaster on 1/2" Rigid Insulation, Studding,
Sheathing and 4″ Brick Venee...….….….….….….….
**
Brick
Furred and Plastered 8"
"
"
12″
Plaster on 1½" Rigid 8"
Insulation, Furred 12″
**
"
•
"
Hollow Tile Stucco Exterior
Furred and Plastered 8"
10"
8"
Plaster on 1/2" Rigid
Insulation, Furred, 10"
Hap
"
Nu mi
"
Limestone or Sandstone
Furred and Plastered
"
**MUNDO
8"
12"
Plaster on 1/2" Rigid 8"
Insulation, Furred 12″
**
"
………………………… «
Brick, Tile, Stone, Cement, Etc.
DO NO •
AUTO
……………
*******
Con
TA
C
……………………………
…………
D
1 1 1 1 1 ……………OMPANION
****
100 4 4 4 4 an à la o a d
………………… TODA
SE O
MOON……………… O O O O
LAGUNEANNA AND ADOTCOUNTERSUND
da………………………
U GAD DU DU DUAL S
COCOSMO -----
………………… 10 0 0 0 0 AND AS TO
mana de é à dema
………………………………
…………………………. 10 0 0 0 0 On a bat
Dimana
LOODUDA ODG
…………………
POSTANU saborear
CONTATT
Hollow Cinder Block, Plain Exterior
Furred and Plastered 8"
12"
Plaster on 1½" Rigid 8"
Insulation, Furred 12"
Asterisk indicates coefficients and divisors most commonly used.
FONTE O CA 90044
Warm
B.t.u. Loss Steam Water
Coefficients Divisors Divisors
…………………………………………
·6 –
.072
.074
.19
.20
.30
.24
222222
.19
.26
.26
.20
.19
.37
.33
.25
.23
.27
.25
.20
.19
45
45
1,8
17
11
14*
15
18
13
13
17
18
9
10
14
15
12
14
17
18
30
30
11
10
7
8.50
9
11
8
8
10
11
6
ܩ
8.5
9
7
.
8.5
10
11
HOW
H O W
TO FIGURE RADIATION
Hollow Concrete Block, Plain Exterior
Furred and Plastered 8"
12"
8"
Plaster on 1/2" Rigid
Insulation, Furred 12"
•
**
C
❤………
KOMISTU and 4 do 10 kaş Danse naam e o agrada --
GOOD MAN ON GO ON wa passando a math Quart
Plan 1-0-0-0 at de to tie a o met de totaal ( 4 təpə tutan da
Wood Lath and Plaster
Wood Lath and Plaster, 3/4" Flooring........
Metal Lath and Plaster
Metal Lath and Plaster, 3/4″ Flooring
Plaster on ½" Rigid Insulation
Plaster on ½" Rigid Insulation, 3/4″
Flooring
Metal Lath Plaster 1½" Rigid Insulation
between joists
Metal Lath Plaster 1½" Rigid Insulation
between joists, 3/4" Flooring
Metal Lath and Plaster 3" Rock Wool
Fill
Metal Lath and Plaster 3%″ Rock Wool
Fill, 3/4" Flooring
…………… - 4 à un mod and w
…………………… O O O O O O
Floors and Ceilings
Exposed
NOTE: It is assumed that the temperature of unheated attics will be 35° F.
when the rooms below are heated. If ceilings are insulated this
temperature will be lowered, depending upon the heat transmission.
through the ceiling. These divisors for ceilings are based on
35° F. temperature difference.
…………………
………………… ON AUTO DA VOS LOS DAGAVONNODA ( Ca
CRISTORANTITOS CAN DO SADA A D A G Data to a page de ………………..
LORI DER STATI
be a team 09
***-**- & Data
LOGO LOGO
› 4, 0 0 Crane de eu
*******SA • 40
FOR A TODOS 001 00
****………O DO SO..
……………
DOMA TAO DE OU On a non ci DO I NO
Warm
B.t.u. Loss Steam Water
Coefficients Divisors Divisors
10
6
11
7
15
9
15
9
.32
.30
.23
.22
ching the maj
Warm
B.t.u. Loss Steam Water
Coefficients Divisors Divisors
.62
11*
.28
24*
.69
10*
.30
24*
.35
20
.21
.26
.17
.079
.068
• Asterisk indicates coefficients and divisors most commonly used.
34
24
40
80
100
7*
14*
6*
14*
12
20
14
24
50
60
-7-
HO W т о
RADIATION
FIGURE
Roofs
Covered with Build Up Roofing Paper, Tar and Gravel
Wood Shingles on Wood Strips, no ceiling
Wood Shingles as above with Lath and
Plaster
Wood Shingles on wood strips with 1½"
Rigid Insulation Plastered
Wood Shingles on wood strips, Lath and
Plaster with 35%" Rock Wool Fill......
Asphalt or Asbestos Shingles, Composition.
Roofing, Slate or Tile Roofing on ¾4″
Sheathing
"
ODERADO O O O O O O e
an
1 1 0 0 0 10 00 0 0 DNIALS
NÚ DO
* 4 4 4 4 MO
*** NO
Roof as above with Lath and Plaster………………………..
Roof as above with ½" Rigid Insulation
Plastered
Roof as above Lath and Plaster with 3%"
Rock Wool Fill
0% à à à mê TUD
BACKG
………………….ad e o dos v UTADA.
********iness
a a CMD 4 ·····
d = *
Solid Doors 3/4″ thick
Solid Doors 1-1/16″ thick
Solid Doors 1-5/16″ thick
Doors with Thin Panels
Single Glass Window or Skylight.….….….………..
Double Glass Window or Skylight….…….......
1 Air Change per cu. ft. per deg.
1½ Air Change per cu. ft. per deg.
2 Air Change per cu. ft. per deg.
BLATTE 1 0 4 1 0-1 1
1 - * * * -
A A A A D D D Date de dum qu
------o ș then à à 4 CAN CO
10 4 0 10 4 14 UURI dag
Doors, Glass and Air Changes
SEO Carta det i da
** ** ** * me à a la ate a co
que o de a
a VODO
be a c 1 0 0 0 0 1 d
GOLF dat à a me a
AN UNO DO SO
Warm
B.t.u. Loss Steam Water
Coefficients Divisors Divisors
.46
7
4
.30
.21
.059
.56
.34
.23
.065
1.
1.13
.45
11
.0181
.0271
.0362
.17
50
6
10
15
50
5*
6*
6.5*
3.4*
3*
7.5
7
190*
125*
95
10
Warm
B.t.u. Loss Steam Water
Coefficients Divisors Divisors
.69
.59
.52
35
3.7
6
୨
30
3*
3.7*
4*
2*
2*
4.7
120*
80*
60
* Asterisk indicates coefficients and divisors most commonly used.
NOTE: For one air change use 200 as divisor instead of 190 for simplicity.
HOW
TO FIGURE RADIATION
Air Changes
In almost all formulas for figuring radiation there exists one particu-
larly troublesome factor. This factor is the number of air changes per hour
for which allowance should be made.
As a guide in determining the number of air changes per hour, the
following table can be used, subject to construction conditions in each case.
Description
Rooms with window one side
Rooms with window two sides
Rooms with window three sides
Rooms with window four sides
Bathrooms
Private Garages
0 0 1 N O D C Dm E DODO O O O O O JAMAIKA DODOMA CONSEGNA D A D DUNIA
Pasomota MOTO
Net sq. ft. exposed wall (less glass)
Net sq. ft. Glass
Net sq. ft. Ceiling
Cu. ft. of Air
FACINTURONES 0 0 20
* 1 0 1 0 0 0…………-SECTIO 0 0 0 0 MODO O O - DOO
GUTEGADORES
vene naba
STORE…..……………………» OTTO
10 0 0 0 0 VND SECON
When metal weather strips are provided, the number of air changes
can be reduced by 40% for double hung wood sash and by 55% for double
hung metal sash.
Fireplace chimneys should be provided with an accessible damper so
the chimney can be closed tight when the fireplace is not being used.
O JORDAN 2 MIN 100mm pe DN DE DO'N VORUTTOSESIJAT
Example for Use of Divisor Method
To figure this same room which is 12 x 20 with 9' ceiling with four
windows, and two sides exposed, in which case we would consider 1½
air changes per hour, and with ceiling exposed to unheated attic and other
conditions as stated in example we proceed as follows:
Air Change
Per Hour
1
11/2
2
2
2
2 to 4
228 divided by 14 16.2
60 divided by 3=20
240 divided by 24=10
2160 divided by 125 = 17.2
Sq. ft. Steam Radiation 63.4
-9-
HOW TO FIGURE
FIGURE RADIATION
+
If this same room is to be heated by steam from -10° outside to 70°
inside, by referring to Table 2 of correction factors, we find opposite -10
and under 70° the multiplier 1.14 showing that for this temperature differ-
ence there will be required 14% more radiation than for 0 — 70º.
If this same room is to be heated from 0° outside to 80° inside with
180° average water in the radiator, by referring to table 4 of correction
factors we find opposite 0° and under 80° the multiplier 1.14 showing that
for this temperature and with 180° average water temperature in the
radiator, there will be required 14% more radiation than would be required
for standard conditions.
The divisor method is well adapted for use as a quick check formula
for checking the amount of radiation shown on plans or installed in a
house and when used for this purpose does not involve complicated cal-
culations.
The application for this quick check would be to divide the total net
wall, net glass, ceiling, floor and cubic contents and any other heat losing
surface in the entire building by the divisor shown in Table 1.
How to Figure Radiation for Temperature
Other Than 0-70 Deg. F.
The following tables of correction factors are for computing the
amount of radiation for temperatures other than zero outside, 70 degrees
inside, for low pressure steam and for water temperatures in the radiators
from 170° to 200° F.
10-
HOW TO RADIATION
FIGURE FIGURE
I
Outdoor Temperature
I
Table 2
Steam
Correction Factors for Temperatures Other than 0° F. — 70° F.
(240 B.t.u./sq. ft.)
Steam Temperature 215°
8 n on G
60
50
45
40
35
8 2 2 2 9
30
25
20
15
10
S
0
S
-10
-15
-20
-25
-30
50°
0
.06
.12
.18
.24
.30
.36
.42
.48
.54
.61
.67
.73
.79
.85
.91
.97
55°
0
.06
.13
.19
.25
.31
.38
.44
.50
.57
.63
·.69
.76
.82
.88
.94
1.01
1.07
Indoor Temperature
60°
65°
0
.07
.13
2020
.26
.33
..39
.46
:52
.59
.65
.72
.78
.85
.92
.98
1.05
1.11
1.18
.07
.14
1 2 2 2 2 ♡ no on a 8
.20
.27
.34
.41
.48
.55
.61
.68
.75
.82
.89
.96
1.02
1.09
1.16
1.23
1.30
70°
1 2 2 4 4 2 ĥ J F
.14
.21
.29
.36
.43
.50
.57
.64
.71
.79
.86
.93
1.00
1.07
1.14
1.21
1.29
1.36
1.43
75°
.23
.30
.37
.45
.52
≈ 8 6 2 ≈ 2.
.60
.67
.75
.82
.90
.97
1.05
1.12
1.20
1.27
1.35
1.42
1.50
1.57
80°
.31
.39
.47
.55
.63
.71
.79
.86
.94
1.02
1.10
1.18
1.26
1.34
1.42
1.49
1.57
1.65
1.73
11-
H O W
TO FIGURE RADIATION
Outdoor Temperature
Table 3
Hot Water
Correction Factors for Temperatures Other than 0° F. — 70° F.
170° Average Water Temperature
60
35
50
45
40
35
30
25
20
15
10
0
<-10
-15
-20
-25
-30
50°
0
.06
.11
.17
.23
.28
34
.40
.45
.51
.57
.62
.68
74
.79
.85
.91
55°
0
.06
སྭཱ ཝཱསསྨཱ - ༣ 8 8
.12
.18
.24
.30
.36
.42
.48
.54
.60
.66
.72
.78
.84
.90
.96
1.02
Indoor Temperature
65°
60°
0
.06
.13
~ 2 2
.19
.25
.32
.38
.44
:
.57
.63
.69
.76
.82
.88
.95
1.01
1.07
1.14
— 12-
ġ å i is a ☺ ☺ ☺ ☺ ☺
.07
.13
.20
.27
.34
.40
.54
.60
.67
.74
.81
.87
.94
1.01
1.07
1.14
1.21
1.28
70°
14
2233
.29
.36
.43
.50
.57
.64
.71
.79
.86
.93
1.00
1.07
1.14
1.22
1.29
1.36
1.43
75°
.23
.31
.38
.46
.54
.61
.69
.76
.84
.92
.99
1.07
1:15
1.22
1.30
1.38
1.45
1.53
1.61
80°
.33
.41
.49
.57
.66
.74
.82
.90
.99
1.07
1.15
1.23
1.32
1.40
1.48
1.56
1.65
1.72
1.81
HOW TO FIGURE RADIATION
Outdoor Temperature
Table 4
Hot Water
Correction Factors for Temperatures Other than 0° F. — 70° F.
180° Average Water Temperature
60
55
50
~ ~ ~ ☺☺A A
45
40
35
30
25
20
15
10
0
5
-10
-15
-20
-25
-30
50°
G
0
.05
.10
.15
.20
.25
.30
.36
.41
.46
.51
.56
.61
.66
.71
.76
.81
55°
If other than 0
manner.
0
.05
.11
.16
.21
.27
.32
.37
.43
.48
.53
.59
.64
G
༢ཙâ་ཆར
.69
.75
.80
.85
.91
Indoor Temperature
60°
65°
0
.06
.11
.17
.23
.28
.34
.40
.45
.51
.57
.62
.68
.74
.79
.85
.91
.96
1.02
.06
.12
.18
.24
.30
.36
.42
.48
.54
.60
.66
.72
.78
.84
40 x .88 = 35.2 sq. ft. should be installed.
.90
.96
1.02
1.08
1.14
70°
.13
.19
.25
.32
.38
.45
.51
.57
.63
.69
.76
.82
.88
.95
1.01
"1.08
1.14
1.20
1.26
75°
If 40 sq. ft. of radiation are required at standard conditions of
070° F. and 170° F. Average Water Temperature and specifications
require o 70° F. and 180° F. Average Water Temperature multiply
40 x .88 found in above table.
.26
.27
.34
.40
.47
.54
.60
.67
.74
.80
.87
.94
1.01
1.07
1.14
1.21
1.27
1.34
1.41
80°
.29
.36
.43
'50
:57
.64
.71
.79
.86
.93
1.00
1.07
1.14
1.22
1.29
1.36
1.43
1.50
1.57
70° F. conditions are specified use table 4 in same
13
HOW TO FIGURE RADIATION
Outdoor Temperature
Table 5
Hot Water
Correction Factors for Temperatures Other than 0° F.
190° Average Water Temperature
60
55
50
45
40
35
30
25
20
15
10
5
0
5
-10
-15
-20
-25
-30
50°
M
0
.05
.09
.14
.18
.23
.28
.32
.37
.42
.46
.51
.55
.60
.65
.69
.74
55°
same manner.
0
.05
.10
.15
.19
.24
mga p
.29
.34
.39
.44
.48
.53
.58
.63
.68
.72
.77
.82
Indoor Temperature
60°
65°
0
.05
.10
.15
.20
.25
.30
.36
.41
.46
.51
.56
.61
.66
.71
.76
.81
.86
.91
40 x .79 = 31.6 sq. ft. should be installed.
If other than O
.05
.11
.16
.21
.27
.32
.37
.43
.48
.53
.59
.64
.69
.75
.80
.85
.91
.96
1.02
70°
.11
.17
.23
.28
.34
.40
.45
.5.1
.57
.62
.68
.74
.79
.85
.91
.96
1.02
1.08
1.13
70° F.
75°
.18
.24
.30
.36
.42
.48
.54
.60
.66
.72
.78
.84
.89
.95
1.01
1.07
1.13
1.19
1.25
80°
~ ~ ♡ + n n ♡ox≈ 8
.32
.38
.44
.50
.57
.69.
.76
.82
If 40 sq. ft. of radiation are required at standard conditions of
0 — 70° F. and 170° F. Average Water Temperature and specifications
require 0 70° F. and 190° F. Average Water Temperature multiply
40 x .79 found in above table.
.88
.95
1.01
1.07
1.14
1.20
1.26
1.33
1.39
70° F conditions are specified use above table in
1
14 -
HOW TO FIGURE RADIATION
Outdoor Temperature
Table 6
Hot Water
Correction Factors for Temperatures Other than 0° F.
200° Average Water Temperature
60
55
50
45
40
35
30
25
alleg
3223
20
15
10
5
0
5
-10
-15
-20
-25
-30
| 1
1.
50°
ܘ
.04
.08
.13
.17
.21
.25
.30
.34
.38
.42
.46
.51
.55
.59
.63
.67
55°
0
.05
.09
.13
.18
22220
.26
.31
.35
.40
.44
.48
.53
.57
.62
:66
.71
.75
Indoor Temperature
60°
65°
0
.05.
.09
.14
.18
.23
.28
.32
.37
.42
.46
.51
.55
.60
.65
.69
.74
.79
.83
.05
.10
.14
S
.19
15 –
.24
is is is is in is in t
.29
.34
.38
.43
.48
53
.58
.63
.68
.72
.77
.82
.87
.92
70°
.10
.15
.20
~ 3 3 - 5 no or no
.25
.31
.36
.41
.46
.51
.56
..61
.66
.71
.76
.81
.87
.92.
.97
1.02
70° F.
75°
.16
.21
.27
.32
∞ : ☺ ☺ à ☺ in is is in
.43
.48
.54
.59
.69
.80
.86
.91
.96
1.02
1.07
1.12
80°
☺ ä äü in a ☺ in is i
.28
.34
.39
.45
.51
.56
.62
.68
If 40 sq. ft. of radiation are required at standard conditions of
0 70° F. and 170° F. Average Water Temperature and specifications
require 0 70° F. and 200° F. Average Water Temperature multiply
40 x .71 found in table 6.
.73
.79
.84
.90
.96
1.01
1.07
1.13
1.18
1.24
40 x .71 = 28.4 sq. ft. should be installed.
If other than 0 70° F. conditions are specified use table 6 in same
manner.
HOW
RADIATION
TO FIGURE
Assumed Temperatures
Living rooms
Bathrooms
70° F.
75° F.
40 to 50° F.
35° F.
Above temperatures should be measured at a distance of 5 ft. above
floor level, and at least three feet from exposed walls.
Om oss
Private Garages
Unheated Attics
In a
………………
LA DE SU
DO DO ME ON
att an do to a D D Da
FOO
Systems
One Pipe Gravity Steam
Pressure or Vacuum
In this system the condensation returns to the boiler by gravity. The
high point of the main is directly over the boiler and the system may
comprise one or more circuits.
There is no set rule regarding the distance from the boiler water line
to the low point in the main. This distance is governed entirely by the
drop in pressure at a point where the last radiator is taken off the main.
In designing a one pipe gravity system of piping the following is
important:
1-The riser from boiler outlet should be full size and run as high
as possible before branching out and from this high point the
main should pitch down 1½" in each 10 ft.
2-That the piping system shall be free to expand when heated.
3-That a quick vent air valve be installed at the end of each circuit
and at other points where air might accumulate.
Size of Mains
Up to 190 sq. ft. radiation
Up to 390 sq. ft. radiation
Up to 650 sq. ft. radiation
21/2″
The sizes of flow mains are for use when main does not exceed 100 ft.
in length; over 100 ft. use one size larger main. The main should not be
reduced more than one pipe size and where reduction is made this must be
accomplished by using an eccentric fitting. The main should extend full
size to a point 3 ft. beyond last take off, before making reduction for
return to boiler.
The use of the Hartford loop is recommended.
11/2"
2"
A MADARA
·16-
HOW TO
RADIATION
FIGURE
Branches and Risers
Branches should be taken off the top of the main, preferably at a 45°
Horizontal branches should be one size larger than vertical risers, especially
when the riser is supplying its full amount of radiation as shown in the
following table.
In no case should a horizontal branch be over 6' in length.
Pipe & Valve
Size
Inches
1
11/4
11/2
Size of Branches, Runouts, Risers and Valves
Up Feed
Square Feet Standard Radiation
QUICK VENT
POP SAFETY
FEED WATER
DRAIN COCK
Horizontal
Branches &
Runouts
20
55
80
口
​000
17-
C
Vertical
Risers
45
100
150
Radiator
Valve
24
60
80

AIR VALVE
RADIATOR VALVE
DAMPER REGULATOR
STEAM PRESSURE GAUGE
WATER GAUGE GLASS
PIPING
PITCHES DOWNWARD
IN DIRECTION OF ARROWS
TYPICAL LAYOUT OF
ONE PIPE STEAM SYSTEM
HOW
TO FIGURE
FIGURE RADIATION
In this system is embodied a flow main and flow risers, return main
and return risers. The mains and horizontal branches should be designed
so that the lowest point in the piping system will be directly over the
boiler and pitched up at least 1/2" in each 10 ft. length to the far end of
the main. The return main is run parallel to the flow main of the same
size, and is pitched in the same direction.
Table of Mains Two Pipe Gravity Warm Water System
Square Feet Standard
Radiation
Standard Conditions
Two Pipe Gravity Warm Water System
Up Feed
175
350
550
21/2
850
3
Above sizes are for use when flow mains do not exceed 100 feet in
length.
If a main is reduced there should be a branch taken off the reducing
fitting, preferably on a 45° from the top, for the purpose of relieving
the air.
**
Square Feet Standard Radiator
Standard Conditions
First Floor
"
Up to 20 sq. ft.
From 21 to 45 sq. it.
51 to 90
101 to 140
146 to 250
"
Size of Risers
Two Pipe Gravity Warm Water
494 Skor Kapak sat også serra15sales 00006 AUS EXIT JA TER 2484 DAMPI
:
"
•
:
……………¶unstakadem
SITE KIT --------
Size
Flow and Return Main
Inches
11/2
2
CUISSONA
18-
sasamako sana s kadroes one amb tot el a a é o de o à a ser a sa & maling-a
HÜLLTÜR sense na to da min d a c 40
SO I TO UNDERSTá an ca a v DATE Maa Dan panta ka sa ne da ta mà 1 1 1 a 1 RUNM-II De
CLAMOĞORTANDINò à thô g en 5-kamaan sa 0 0 6. 200 2 0NT PRO=AT de à à dé dráhy a SUTARTIST
Pipe Size
In Inches
1/2
3/4
1
11/4
11/2
HOW
FIGURE RADIATION
т о
Square Feet Standard Radiator
Standard Conditions
Second Floor
Up to 28 sq. ft.
From 29 to
29 to
61 to 110
111 to 230
•
"
Third Floor
**
60 sq. ft.
*
**
Gaon Bad 6-06-02
•
Up to 35 sq. ft.
From 35 to
35 to 80 sq. ft..
46
•
**
81 to 140
146 to 300
10
15
20
26
18
21
24
30
35
..
----0---
**
10 à un à can be seen makam van 2012 MAI SUTI DOTONEUSO MO Q
…………
med at
A to use a que — no ano e a
……………….
DENNE O O O O O A
.....
Nominal Capacity-Gallons
- La
Tampa de pe 1 à a A A D G 2 1 9 0 mm 4.
Closed System
19 -
M
………… • • • • •..
Expansion Tank Capacity
Open System
60-0 0 0 Stand one pOG NO
PAOLO DO Susta
YOU SUR LE VÉ Ma a sam mu da NOWTF004) preda
------------1945
………………… mp4 S
All of above pipe sizes based on steel pipe.
All horizontal branches and runouts to be one size larger than vertical
risers.
140 4 0 0
Expansion Tank
Many Warm Water Heating installations cause needless expense and
trouble through the use of an expansion tank of inadequate size. It is
important that the expansion tank be placed at least 3 feet above the top of
highest radiator, and that it be connected with an expansion pipe, an
overflow pipe, and a vent.
Pipe Size
In Inches
350
450
650
900
1100
1/2
3/4
Square Feet of Radiation
300
500
700
950
1
11/4
1/2
3/4
1
11/4
HOW
TO FIGURE RADIATION
C
The overflow line should be run to a suitable drain and should be
vented, to prevent syphonic action. The vent or overflow line should in
no case be run to the outside of the building as hoar frost is liable to
accumulate. Freezing of expansion tanks, expansion or overflow lines
must be avoided.
FEED WATER
DRAIN COCK
TO
EXPANSION TANK
Food
1
KEY COMPRESSION,
20 -
G
ŒEE
RADIATOR VALVE`
DAMPER REGULATOR
COMBINATION ALTITUDE GAUGE
AND THERMOMETER
PIPING PITCHES DOWNWARD
IN DIRECTION OF ARROWS
Locating Radiators
For the best results, radiators should be placed adjacent to or near
the exposed surface offering the greatest heat loss from the room.
TYPICAL LAYOUT OF
TWO PIPE GRAVITY
WARM WATER SYSTEM
1

Pipe, Fittings and Pipe Fitting
883
CHAPTER 46
Pipe, Fittings, and
Pipe Fitting
1. Pipe
What kind of pipe is ordinarily used on heating jobs and
for many other applications?
Ans. Wrought pipe.
How is wrought iron distinguished from wrought steel
pipe?
Ans. Manufacturers stamp each length of wrought iron pipe
“genuine wrought iron”.
What other kind of pipe is sometimes used on domestic
jobs?
Ans. Copper or brass.
What is peculiar about the rated sizes of wrought pipe?
Ans. The diameters as given are far from the actual diam-
eters especially in the small sizes.
Thus a pipe known as 14 in. (rated size) has an outside diameter of
.54 in. and internal .364 in.
What are the three grades of pipe as manufactured for
different pressures?
884
Pipe, Fittings and Pipe Fitting
LENGTH OF EFFECTIVE THREAD
1.33
NORMAL ENGAGEMENT BY HAND
BETWEEN MALE & FEMALE THREAD
F
F30.
- P
PITCH
-E
f
30°
90
B
PITCH DIA.OF THREAD
AT GUAGING NOTCH
IMPERFECT
THREADS DUE
TO LEAD OF DIE
TAPER I IN 16 MEASURED
ON DIAMETER
H
1
ACTUAL INSIDE
A-PITCH DIA. OF THREAD
1 AT END OF PIPE
Fig. 1.-American Briggs standard for taper and straight pipe threads and lock nut threads.
----1.315--
----1.315--
←---1.315---
ОО
STANDARD
EXTRA HEAVY
DOUBLE
EXTRA HEAVY
Figs. 2 to 4.—The three weights of wrought pipe. Fig. 2, standard; fig. 3, extra strong; fig. 4, double extra
strong. Sometimes the word "heavy" is used in place of strong. The figures are actual size, showing propor-
tions of the three grades of 1 inch wrought pipe.
DIA.
.
G
O. D. OF PIPE
For letter dimen-
sions, see table
page 886.

+358
$599



Pipe, Fittings and Pipe Fitting
885
Ans. 1, Standard; 2, extra heavy (or extra strong); and 3,
double extra heavy (or double extra strong).
How do they get the different thickness of metal without
changing outside diameters?
Ans. By reducing inside diameter.
Bizo
KKKK
11
114
>
24
*
JA
Diameters
Inches | Inches | Inches
ห
.405
.269
X
.540
.364 .088
X .676
44
.840
X
.493 .091
.622 .109
1.050 .824 113
1.315 1.049 .133
1.380
.10
1
1 660
1.900
1 610
.145
2.375
2.067
.154
2.875
2.469
203
216
3.500
3 068
3.548
4.000
4.500
4.026
.237
434 5.000 4.506 .247
258
5.563 3.047
.625
280
6.065
7.625 7.023 301
8.625 8.071 277
7.981 .322
8 HI
.342
825
625
10
10
10.750 10.192 279
10.750 10.136 .307
365
11 11.750 11.000 .373
10 10.750 10.020
12
12
Đ
Exter-
Sai
Properties of Standard Wrought Pipe
LENGTH OF PIPE
PER SQUARE
FOOT OF

Nomi
nai
Approx Thick-
imate bess
Inter-
nai
Inches
.068
.228
CIRCUMFERENCE
IRCUME
Exter-
Dal
Inter-
pal
TRANSVERSE AREAS
13.750 13.000 .330 40.055 37
12.750 | 12.000 .875 40.055
Exter-
na!
Inter-
امه
Metal
Exter- Inter-
Dal
nal
Surface Surface
Inches
Inches8q. Ins.] Sq. Ins.| Sq. Ios.
.845 .129
1 272
.037
.072
1.144
.229
.104
.125
1.696
2.121
1.549
358
.191
.167
2.639
1 954
.354
.304
250
3.299
2.589
.866
.533
.333
4.131
3.296
1.358
.804
.494
5.215
4.335
.669
5.989
799
1.075
7.461
1.704
9 032
10.996
12.568
14.137
2 228
2 680
3.174
.848
2 164 1 495
3 058 2.835 2.036
6.494 4.430 3.355
7 757 •8.492 4.788
9.638 9.621 7.393
11.148 12.566 9.886
12.648 15.904 12.730
15.708 | 14.156 || 19.635 15.947 3.688 .763
17.472 | 15.856 24.306 20.008 4.300 .686
20.813 19.054 34.472 28 891
8.581 .576
23.955 | 22.063 45.664 28.738
6.920 800
27.096 25.356 ||| 58.426 $1.161 7.265 442
27.096 25 073 58 426 50 027 8.399 442
30.238 | 28.089 72.760 62.786 9.974 396
33.772 33.019 90.763 81.585 9.178 .353
33.772 31 843 90 763 80.691 10.072 355
33.772 | 31.479 90.763 | 78 855 11 908 355
36.914 24.858 108.431| 95 033 13.401
|127 676| 114.800| 12.876
127 676|113.097| 14.879
325
Feet
9.431
7.073
5.658
4.547
3.637
2.904
2.301
2.010
1.608
1 328
1 091
.954
•
Gadg
"Length
of Pipe
Con-
sainiog
Ono
Cuble
Foot
.427
.374
376
381
.347
.315
.318
NOMIYAL WHIONT
FER FOOT
Puin
Ends
.424
7.747
.567
6.141
.850
Feet Feet
14.199 ||2533.775 .244
10.493 1383.789|
754 360
473.906
270.034 1 130
166.618|| 1.678
96.275 2.272
70.733 2 717
42.913 3 652
30.077 8 793
19.479 7 575
14.565 0.109
11 312 10.790
9.030 12 338
7.198 14.617
18.974
23 544
24.696
4 635
3.641
2 767
2 372
1.847
1 547
1 243
1 076
918
847
.756
4.984
3 717
.629 ·
543
.473
478
2 815
2.878
28.554
2.294
33.907
35 000
1.765 31.201
1.785 34.240
1.826 40.483 41 132
1.515 45.557 40.247
1.254 43.773 45.000
1.273 49.562 30.706
Threaded
and
Coupled
.245
.425
.568
.852
1.134
1.694
2.281
2.731
2.678
5.819
7.618
9.202
10 889
12.642
14 810
19 183
23.769
25 000
28.809
34.188
32.000
Number
of
|Threads
Per
Inch of
Screw
27
18
18
14
14
1114
1114
1114
11:5
8
8
$
8
8
8
8
8
•
8
8
·
NOTE.- The above table appears on page 367, repeated here for the convenience
of the reader. On page 368 will be found tables covering Extra Heavy and Double
Extra Heavy pipe.
886
Pipe, Fittings and Pipe Fitting
Nominal
Size
at accusa akan data
1/8
223
1/4
3%
1/2
8/4
1
14
Inches Inches Inches Inches Inches
.2638
.180
.36351 .37476
.47739
.48989
.4018 .200
.61201 .62701
.4078
.240
.75843
77843
5337
.320
.96768 98886
1.21363 1.23863
1.55713 1.58338
1.79609 1.82234
.5457 .339
.6828
.7068 .420
.7235
.420
.436
.682
2.26902 2.29627 .7565
2.71953 2.76216 1.1375
3.34063 3.38850 1.2000
3.83750 3.88881 1.2500
.766
.821
4.33438 4.38713 1.3000 .844
4.83125 4.88594, 1.3500 .875
5.39073 5.44929 1.4063
.937
6.44609
6.50597 1.5125
.958
7
7.43984
7.50234 1.6125 1.000
8
8.43359 8.50003 1.7125 | 1.063
9
10
1.210
12
1.360
1.562 14.000
9 42734 9.49797; 1.8125 1.130
10.54531 10.62094 1.9250
12.53281 12.61781 2.1250
14 0:D. 13.77500 13.87262 2.250
15 O.D. 14:76875 14.87419 2.350
16 O.D. |15.76250 15.87575 2.450
18 O.D. 17.75000 17.87500 2.659
20 O.D. 19.73750 19.87031 2.850 2.125 20.000
1.687
15.000
1.812
16.000
1 2.000
18.000
2.250 22.000
22 O.D. 21.72500 21.86562 3.050
24 O.D. |23.71250|23.86094 3.250
2.375 24.000
**
12
BRIGGS' STANDARD PIPE THREADS
(Dimension letters refer to Fig. 1)
21/2½
31/2
4
4/2
5
6
A
I
B
}
A=G-(0.05G +1.1) P
B=A+.0625 F
E=P (0.8G +6.8)
DEPTH OF THREAD = 0.8 P

I
E
·
·
F
f
•
G
Inches
.405
.540
.675
.840
H
Inches
.269
.364
.493
.622
.824
Depth of Number
of
Threads
Threads
Inches Per Inch
.02963 27
.04444
18
.04444
18
.05714
14
.05714
14
1.049
.06956
1.380
.06956
1.610 .06956
2.067 .06956
2.469
.10000
.10000
.10000
. 10000
.10000
10000
10000
.10000
.10000
.10000
.10000
.10000
10000
10000
.10000
.10000
.10000
.10000
.10000
1.050
.400 1.315
1.660
1.900
2.375
2.875
3.500
3.068
4.000
3.548
4.500
$4.026
5.000
4.306
5.563
5.047
6.625
6.065
7.625
7.023
8.625
7.981
9.625 8.941
10.750 10.020
12.750 :12.000
11/2
1112
11/2
11/2
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
∞ ∞ ∞ ∞
8
8
8
Pipe, Fittings and Pipe Fitting
887
How are pipes and fittings joined?
Ans. Usually by threaded joints but the joints are frequently
welded, especially on large size pipe.
What do they call the thread used on pipes?
Ans. Pipe thread.
What is the peculiarity of the pipe thread and why so
made?
Ans. It is tapered, the object being to get tight joints.
Evidently the more turns in screwing up the pipe, the tighter the fit.
What taper is used?
Ans. 1/32 in. per foot.
How about the number of threads per in.?
Ans. They vary from 27 threads for 1/8th pipe to 8 threads
for 21½ in. pipe and larger sizes.
What do you mean by "Properties"?
Ans. All the data or particulars such as size, diameters,
threads, areas, capacity, etc.
2. Fittings
What are pipe fittings?
Ans. Connections, appliances, etc. designed to be used in
connecting pipes. They are: elbows, bends, tees, crosses, plugs,
bushings, reducers, etc.
888
Pipe, Fittings and Pipe Fitting
What is a nipple?
Ans. A short piece of pipe 12 ins. in length and under and
threaded at both ends.
How are nipples classified as to length?
Ans. As: 1, close; 2, short or shoulder; 3, long; and 4, extra
long.



Figs. 5 to 7.-Close, short or shoulder and long wrought nipples. Standard
Tengths are (for 1 in. pipe) 12, 2 and 2½ to 4 ins. respectively.


1.
Figs. 8 and 9.-Long screw nipple and right and left hexagon center nipple.
The long screw nipple has one end of the coupling and follower faced to make
a tight joint.

LOCKNUT THREAD
STANDARD PIPE THREAD
Fig. 10.-Tank nipple, 6 ins. long over all. Tank nipples have an American
Briggs standard lock nut thread 4 ins. long on one end, and a standard pipe
thread on the other end. Regularly made in sizes 1/4 in. to 3 ins.
↓
Pipe, Fittings and Pipe Fitting
889
What is a lock nut?
Ans. A hexagon nut having a threaded hole to correspond
with pipe size and having also a recessed or grooved faced end
to make a tight joint with a long nipple.
What is a long screw nipple?
Ans. One having a long thread on one end on which is a
coupling and lock nut.


་་ལ"
Figs. 11 and 12.-Lock nut and coupling.
How does it work?
Ans. The jamb surface of the coupling and lock nut being
faced, the combination forms virtually a union with male and
female ends.
How do nondescript or so called plumbers make a short
nipple on the job?
Ans. By using a coupling because they don't own a nipple
holder.
This item will be taken up with some acridity at length under “Pipe
Fitting" as alleged plumbers who resort to such technique should not
be tolerated.
What is a coupling?
Ans. A fitting for joining pipes of the same size and having
female threads at each end.
In supplying pipe, a coupling is usually included with each length.
890
Pipe, Fittings and Pipe Fitting




DIAMETER·
Figs. 13 to 17.-Various couplings. Fig. 13, standard wrought coupling; fig. 14,
malleable right and left coupling; fig. 15, hydraulic coupling, fig. 16, sleeve
coupling, fig. 17, extension piece or coupling with female and male threads.
C
B
O
BOLT
CIRCLE
A
[ [ l l l l l
m!!!
ܘ ܝ
B
AT



1:00
D
Figs. 18 to 21.—Standard flanges for 125 lbs. working pressure. A, common;
B, eccentric; C. solid (16 in. o.d. (outside diameter) and smaller); D, solid
reinforced.
→
taimene



C

A
Figs. 22 to 24.—Extra heavy flanges for 250 lbs. working pressure. A, solid,
16 ins. and smaller plain face; B, reinforced, 18 ins. and larger; C, eccentric
plain face.
Pipe, Fittings and Pipe Fitting
891
GASKET
G
1005
SHOULDER
END



TIGHT
SCREW
RING

五​.
GASKET
THREADED END
Figs. 25 to 28.-Ordinary malleable union disassembled to show parts. It con-
sists of three parts and a gasket, as shown. In assembling the gasket G,
is placed over the projection on the shoulder and so that it is in contact with
surface L. The ring is slipped over the shoulder end and the threaded end placed
in position so that the flat end surface F, presses against the gasket and then the
ring is screwed firmly into the threaded end. Since the shoulder on the shoulder
end cannot back off the ring, the two ends are pressed firmly together against
the gasket by the ring, thus securing a light joint.
F

M
S
LEAK

GOOD ALIGNMENT
BAD ALIGNMENT
Figs. 29 and 30.-Limitation of the ordinary gasket union. The alignment
must be good to secure a tight joint. In the figure the ring is omitted for
clearness. If both ends be in line and firmly pressed together against the gasket
by the ring, the gasket will bear evenly over the entire contact surfaces and
the joint will be tight. If the two ends be out of alignment when the ring is
screwed tight it will bring great pressure on the gasket at M, whereas the sur-
faces will not come together at the opposite point S, thus causing a leak,
892
Pipe, Fittings and Pipe Fitting
What is a union?
Ans. A "make up" fitting.
What do you mean by "make up"?
Ans. Joining one pipe line with another or fitting in a fixed
position, a union being used to join them. The union consists of

GROUND
JOINT
O
Fig. 31.-Jefferson brass to iron ground joint; sectional view, showing construc-
tion of joint. The composition ring is forced into the groove under great hy-
draulic pressure and becomes virtually a part of the grooved end.
1
DART
PATENT
nalit
the
14
APR 1,1890
HUR
COMPOSITION
RING
A

Y
Fig. 32.-Dart double composition seat spherical ground joint, female union,
illustrating composition to composition contact.
Pipe, Fittings and Pipe Fitting
893
two parts joined together by a gasket or ground joint brought
together by a nut.
What is a bushing?
Ans. A fitting used to connect the male end of a pipe to a
fitting having a female thread and of larger size. It consists of a
hollow plug with male and female threads to suit the different
diameters and part of its length having hexagon flats so that it
may be screwed on with a monkey wrench.




Figs. 33 to 37.-Various bushings. Fig. 33, plain hexagon nut bushing reducing
one size; fig. 34, plain hexagon nut bushing, reducing more than one size; fig.
35, faced bushing; fig. 36, eccentric bushing, reducing two or more sizes;
fig. 37, offset bushing.



Figs. 38 to 40.—-Various reducers. Fig. 38, plain reducer for gas or low pressure;
fig. 39, flat band or reinforced reducer for steam; fig. 40, eccentric reducer.
What mistake is made in ordering bushings?
Ans. Don't call them reducers.
**
What is a reducer?
Ans. A fitting for joining pipes of different sizes and having
a female thread at each outlet.
894
Pipe, Fittings and Pipe Fitting
What is an eccentric reducer?
Ans. A reducer with the axes of the two outlets offset.
What is an elbow?
Ans. A fitting used to change the direction of two pipės
which it connects.
What are the standard angles?
Ans. 90°, 60°, and 22½°.

Fig. 41.—Standard cast iron offset. Regular sizes 34 to 6 inches, to offset, 4, 6 or
8 inches.

90°
GO!
1ヶ
​Figs. 42 and 43.—Standard elbow angles. Fig. 42, standard for gas, water and
steam; fig. 43, standard for drainage fittings. For steam, special angles such as
22½° and 60° although they can be regularly obtained from most supply
houses, are best avoided where possible.
Pipe, Fittings and Pipe Fitting
895
What do the listed angles measure?
Ans. The angle is not the angle between the two pipes, but the
angle between the axis of one pipe and the projected axis of the
other pipe.
90
What is a "street" elbow?
Ans. An elbow having a female thread at one end and a
male thread at the other.


|||||||||
45°


22
STREET
Figs. 44 to 47.-Various elbows. Fig. 44, 90°; fig. 45, 45°; fig. 46, 22½°; fig.
47 street elbow.
|||||||
What is a bend?
Ans. An elbow whose radius of curvature is longer than that
of an elbow.
896
Pipe, Fittings and Pipe Fitting
{
What is a return bend?
Ans. A U-shaped fitting or a 180° elbow.
What are the different patterns of return bends?
Ans. Classed with respect to the distance between the axes
of the two openings, they are called: 1, extra close; 2, close;
3, medium; 4, open; and 5, wide.



WWW.
به
"


Figs. 48 to 52.-Various malleable return bends. Fig. 48, close pattern without
bead; fig. 49, close pattern with bead; fig. 50, medium pattern; fig. 51, open
pattern; fig. 52, wide pattern.
How many patterns are usually carried in stock in small
or nondescript supply houses?
Ans. Medium and open, sometimes the close pattern is to
be found.
What is a pitched return bend?
Ans. A return bend whose outlets are tapped with "pitch"
that is, so the pipes when screwed into the fitting will not be
parallel but spread slightly.
Pipe, Fittings and Pipe Fitting
897
What is the object of the pitch?
Ans. For making up so called "coils" consisting of short
pipe lengths connected with pitched return bends.
The following tables give a listing by Crane.
The author in building his super steam generator used standard
return bends without pitch and 2 ft. lengths of ½ in. pipe. With this
length it was possible to screw on the return bends by slightly prying
the pipes apart with a wedge. See pages 124 and 204.
PITCHED RETURN BEND
RETURN BEND WITHOUT PITCH
FITTING CAN BE SCREWED ON

A
PITCH
ANGLE
CLEARANCE
B NECESSARY
A
B
FITTING CANNOT BE SCREWED ON
TO SCREW
ON FITTING

INTERFERENCE
Figs. 53 and 54.-Coil being made up with short pipe lengths and with return
bends having "pitch" and no pitch. If the threads be tapped in the fitting
at a slight angle so that the pipes will be inclined to each other as in fig. 53,
there will be room enough to screw on bend A, without encountering fitting B.
If the bends have no pitch, as in fig. 54, then in screwing on bend A, the
other bend B, will be in the way, making it difficult to screw on A. Of course
this interference may be overcome in special cases by prying the pipe ends
apart with a wedge. The author made up a number of 12-inch coils with 2-foot
pipe lengths by this method. The minimum length of pipe that can be made up
in this way will, of course, depend on the size, and is best determined by experi-
ment. With 12-inch pipe, the 2-foot length is about as short as should be used,
though it is probably possible to reduce the length to 12 feet.
898
Pipe, Fittings and Pipe Fitting
Size
\\\\\\
1
11/4
1/2
2
SO CO SE LO
8
212
3
5
3½
4
Malleable Return Bends
(Dimensions as manufactured by Jarecki Mfg. Co.)
Open


Extra close
114
19/16
·
to
to
Center Weight Center Weight Center Weight Center
to
per 100
per 100 to per 100
center plain center banded center banded center
•
77
92
Close
3
7/8
118
138
134
2223 45
3%
218 168
21/2 244
234 388
631
880
1,400
412
6
15.5
22
35
2378
100
Medium
1/4
1.9/16
17%
21/4
29/16
31/16
•
34
60
92
160
255
337
1%
11
11/2
11122
21/2
3
31/2
43/8
Weight
per 100
2248
44
710
Wide

614 1,050
6½ 1,550
1,850
Center
to
center
83 6
140 3 4,412.
5,6,7,8
200 4,5,6,9
310 5,6,8
550
2,6,7,8
■
•
•


Figs. 55 and 56.-Plain or gas pattern malleable and cast iron elbow with side
outlet. Sizes and weights per 100: ¼¼¼, 12 lbs; % XX, 14 lbs.;
%% %, 17 pounds; 2 X2 X%, 24 pounds; 2 X2 X2, 30 pounds;
¾ XX%, 29 pounds; 4X4 X2, 30 pounds; 4X4 X4, 33 pounds;
1 X1 X%, 52 pounds; 1 X1 X2, 51 pounds; 1 X1 X3, 48 pounds; 1X1X1,
55 pounds; 14X1 X1, 110 pounds; 14 X1 X1, 120 pounds; 1½ X
1½ X1½, 150 pounds; 2×2×2, 200 pounds.
Pipe, Fittings and Pipe Fitting
899
What is a tee?
Ans. A branching fitting for joining two pipes running in the
same direction and having an outlet for a branch pipe usually
at 90°.
When the three outlets are of the same size how is the
fitting specified?
1
Ans. By giving the pipe size, as a ½ in. tee, meaning that
all outlets are for 1½ in. pipe.




Figs. 57 to 60.—Various cast iron branch tees or headers.

Nã
Figs. 61 to 63.-Various malleable tees. Fig. 61, plain; fig. 62, band; fig. 63,
11/2
service.
3/4


1/2

1/2
11/4
Figs. 64 to 66.-System of specifying tees. Fig. 64, all outlets the same size,
simply give size of pipe; fig. 65, branch different size than run, specify run first,
thus 1X34; fig. 66, all outlets different size, specify all outlets, run first, thus
114X1X12.
900
Pipe, Fittings and Pipe Fitting
What are the outlets called?
Ans. The two in same direction the run and the other, the
branch.
How is a tee specified?
Ans. The run is given first, then the branch.
Thus when both outlets of the run are of the same size and the
branch different it is specified for instance 1 X 14 meaning that the
two run outlets are 1 in. and the branch 4 in. When all three are
different sizes, it is specified for instance 14 X 1 X 1½ tee, meaning
that one run outlet is 14 in. the other run outlet 1 in. and the
branch outlet 1½ in.
1½
3/4


11
Figs. 67 and 68.-Method of specifying tees to avoid possibility of mistakes.
In ordering fittings, simply make a conventional diagram of a tee and put
down the dimensions desired.

||
་ ་ ་ ་ ་ ་ ་ ་ (
Fig. 69.-Cast iron enlarging or "bull head" tee, enlarging on side outlet.
Pipe, Fittings and Pipe Fitting
901
What is a branch tee or header?
Ans. A tee having two or more branches.
What is a Y branch?
Ans. A tee, whose branch is at some angle other than 90°,
the usual angles being 45° and 60°.

COMP{\\'
Figs. 70 to 73.-Various malleable iron Y branches. Fig. 70, plain Y branch;
fig. 71, flat band Y branch; fig. 72, double Y branch; fig. 73, 60° Y branch.



Figs. 74 to 76.-Various plugs. Fig. 74, hollow; fig. 75, solid; fig. 76, counter
sunk.
What is a cross?
Ans. A four outlet tee forming a cross in shape hence the
name.
What is a plug?
Ans. A fitting for closing the end of a pipe or usually a fitting
having a male thread.
902
Pipe, Fittings and Pipe Fitting
:
What is the difference between a female and a male
thread?
Ans. A female thread is an internal thread and a male thread
is an external thread.
What is a right and left fitting and what is it used for?
Ans. A fitting having right and left threads so that a "line"
may be "made up" without the use of a union.
What is a cap?
Ans. A fitting having a female thread for closing a pipe.

Fig. 77.-Pipe cap. They are made in various types.


PE
naked and hike 1.
dis


HP
Figs. 78 to 81.-Various union fittings; fig. 78, male and female elbow; fig. 79,
female elbow; fig. 80, male and female tee; fig. 81, female tee.
Pipe, Fittings and Pipe Fitting
903
3. Pipe Fitting
What do you understand by the term "pipe fitting"?
Ans. It includes operations which may be listed as: 1, Cut-
ting; 2, threading; 3, tapping; 4, bending; 5, assembling;
6, reaming; 7, cleaning; 8, make up.

MINGE→
Fig. 82.-Pipe vise.
Can He
•
PIVOT
Since pipe comes in lengths of 12 to 22 feet, what must
be done to the pipe in pipe fitting?
Ans. It must be cut to any particular length as may be
required.
How is this done?
Ans. With a hack saw or preferably for convenience by a
pipe cutter.
904
Pipe, Fittings and Pipe Fitting
How is the pipe held while cutting (and threading)?
Ans. In a pipe vise.
How should the pipe vise (having teeth) be adjusted?
Ans. Just sufficiently tight to prevent the pipe slipping but
not so tight as to cause the jaw teeth to unduly dig into the
pipe.


anggungan ang mg
We, the "fe "up and
gopedia
qi 100 •*
METAL UPSET
BY CRUSHING
ACTION OF
PIPE CUTTER WHEEL
L
CLEAN CUT BY HACK SAW
Figs. 83 to 86.—Appearance of pipe and when cut by pipe cutter and by hack
saw. When a pipe cutter is used the external enlargement of the pipe end must
be removed by a file, and the internal burr by a pipe reamer, as shown in figs.
87 and 88.
What is a pipe cutter?
Ans. An instrument usually consisting of a hook shaped frame
on whose stem a slide can be moved by a screw. On the slide
and frame several cutting discs or "wheels" are mounted and
forced into the metal as the whole appliance is rotated about
the pipe.
Why is a pipe cutter preferred to a hack saw?
Ans. The cutting operation is quicker.
Pipe, Fittings and Pipe Fitting
905
What is the disadvantage?
Ans. It crushes the metal, leaving a shoulder on the outside
and a burr on the inside.
What attention should be given to the inside burr
frequently omitted by some plumbers, amateurs and
other nondescripts, and why?
RIGHT WAY
WRONG WAY


Aa
Figs. 87 and 88.-Right and wrong way of removing the shoulder left on pipe
end after cutting with a pipe cutter. Obviously at each stroke the file should be
given a turning motion as indicated by the arrow and dotted position in fig. 87,
removing the excess metal through an arc of the circumference. The position of
pipe is changed in the vise from time to time, till the excess metal is removed all
around the pipe. When the operation is done, as in fig. 88, by moving the file
in a straight line, it will result in a series of flat places.
How is the pipe threaded?
Ans. With stock and dies.
Ans. The internal burr should be removed with a reamer to
avoid future trouble with clogged pipes.
How about the external shoulder?
Ans. A good pipe threader will take care of this, but its pres-
ence requires more "elbow grease" in starting.
906
Pipe, Fittings and Pipe Fitting
What kind of dies should be used and why?
Ans. Adjustable dies because of slight variation in fittings
especially cast iron fittings.
Describe the proper method of cutting a thread with
stock and dies.

TIIN
reamer.
wwwww
REAMER
INSIDE BURR
U
All(20
Fig. 89.-Method of removing burr from pipe end with brace and a burring
Pipe, Fittings and Pipe Fitting
907
Ans. Use plenty of oil in starting and cutting the thread. In
starting, press the dies firmly against the pipe end until they
"take hold." After a few turns blow out the chips and apply
more oil. This should be done two or three times before com-

Fig. 90.-Pipe reamer for removing internal burrs after cutting with pipe cutter.
The practice of some nondescript fitters in not removing these burrs cannot be
too strongly condemned. See fig. 89 how to do it.
BCAM
WITHIN RANGE
TO THE THE
FLOOR


PIPE
NECESSARY
MOVEMENT
BEAM
WHEEL
CUTTER
PIPE
NOT
WITHIN RANGE
NECESSARY
BILL
ROLLER
CUTTER
MOVEMENT 360°
Figs. 91 and 92.—Å well known three wheel pipe cutter (fig. 91) showing why
this cutter is superior to the one wheel cutter fig. 92. The cuts show the compara-
tive movements necessary with the two types of cutter to perform their functions.
The three wheel cutter requiring only a small arc of movement, will cut a pipe in
an inaccessible place as shown, which with a roller cutter would be impossible.
Accordingly, the wheel cutter is said to have a greater range than the roller
cutter and is therefore to be preferred for general work.
908
Pipe, Fittings and Pipe Fitting

20/21
R
15 TOY
20°
R
S
BRIDGEPORTS
Fig. 93.-Adjustable pipe stock and dies for double ended dies. Each pair of
dies, as shown, have one size thread at one end and another size at the other.
Thus the two dies in the stock are in position for cutting 1/2-inch thread and by
reversing them they will cut 3/4-inch thread. The cut shows plainly the reference
marks which must register with each other in adjusting the dies by means of the
end set screws to standard size.

AT LEAST
25°
Figs. 94 to 96.—Lips. Fig. 94 shows a chaser properly lipped for cutting ordinary
steel pipe, the angle line showing how the lip should be ground. Care shoul
be taken when sharpening the face of the chaser to maintain a good cutting
angle of from 15 to 20° as shown. Grinding back the face of the chaser does
no harm if properly done. Fig. 95 shows a die lipped for cutting open hearth
steel pipe, which requires a long, easy lip on account of the tough character
of material. For open hearth steel the lip angle should be 25°. Fig. 96 shows the
ordinary form of commercial die which is unsuitable for cutting, not only steel
but so wrought iron. The lip angle is insufficient. This type of chaser requires
excessive power to cut the thread and the result is that the metal is pushed off
instead of being cut.
*
Pipe, Fittings and Pipe Fitting
909
completing the cut. When complete, blow out chips as clean as
possible and back off the die. Avoid the frequent reversals
usually made by most pipe fitters.
For lubrication, lard will be found preferable to oil. Apply the lard
to the pipe end with a brush. In cutting the thread, the heat generated
will melt the lard which will flow to the cutting edge of the die giving
continuous lubrication instead of spasmodic flooding as is the case
when using oil.*
WORKING
POSITION OF
CHASERS WHEN
THREADING PIPE
LIP
O.Q OF
"PIPE-
POSITION OF
CHASERS WHEN
BEING MACHINED
CLEARANCE
DIA FOR
MACHINING
CHASERS
LIP.
CLEARANCE
Figs. 97 and 98.-Radial or center cut chaser and method of obtaining clear-
ance. To obtain clearance the chasers in the machining position are set out
larger in diameter than the size of pipe for which they are intended. Thus for a
6 inch die, the chasers would be machined to about 7/16 in. greater diameter.
The effect of this is shown in an exaggerated manner in fig. 98, where it can be
seen that the thread of the chasers (of larger diameter) gradually recedes from
the thread on the pipe.
What may be said about the ordinary method of cutting
nipples as indulged in by some alleged plumbers for lack
of proper tools?
Ans. It is very unsatisfactory and should not be tolerated
on first class jobs.
*NOTE.—The author is indebted to Mr. Harbison, thread expert of the National
Tube Co., for this suggestion.
•


910
Pipe, Fittings and Pipe Fitting

2
Fig. 99.—Nipple holder for use with hand stock and dies. As shown the holder
is double ended and holds two sizes of nipples, the one illustrated being for ½
and 3/4 inch nipples. In construction, there is a pin inside the holder having a
fluted end which "digs into" the nipple end when pressed forward by driving
down the wedge. In operation the nipple is screwed by hand into the holder
as far as it will go, then the wedge is driven down sufficiently to firmly secure
the nipple. The holder is so arranged that when the thread is cut, the nipple can
be removed by simply starting back the wedge, which loosens the inner part of
the holder and allows the nipple to be easily unscrewed by hand. The holder
can be used for making either right or right and left nipples.
SIZE OF PIPE
TO BE THREADED

REST
SIZE OF
GRINDING WHEEL
FRONT OF CHASER
CENTER LINE
OF CHASER
CENTER LINE OF
GRINDING WHEEL
Fig. 100. Proper method of grinding chasers to secure clearance in lead or
throat. The chaser is raised or lowered accordingly as the design of the die
Pipe, Fittings and Pipe Fitting
911
How do they do it?
Ans. They take a short piece of pipe with a coupling on the
end as a home made "nipple holder."


WORKING
POSITION OF
CHASERS WHEN
THREADING PIPE
LIP.
*VITTUURINN
20.Н
o D. OF
PIPE
BERLAJÍ
POSITION OF
CHASERS WHEN
BEING MACHINED
CLEARANCE
A f
DIA POR
MACHINING
CHASERS
LIP.
MEEL
REMOVEO
CLEARANCE
Figs. 101 and 102.-Advanced cut or stock on center chaser and method of
obtaining clearance. The cutting edge as shown is set ahead of the radial line
which runs through the center of the chaser. To obtain clearance the chasers
in the machining position are set in smaller in diameter than the size of the
pipe for which they are intended. With this type of die the chasers are set in
as much as the radial cut chasers are set out. This is shown exaggerated in fig.
102 where it can be seen how the chaser thread being cut to a smaller radius
recedes from the pipe thread. In this type of die the rear half or heel of the
chaser should be ground off as shown, otherwise it will drag on the pipe threads.
and injure them.
Fig. 100.-Text continued.
requires. C, indicates the amount of clearance which will be obtained. The
figure shows the approximately correct position for grinding a "stock on center"
chaser to secure proper clearance on lead. The chaser in this case should be held
in a perfectly horizontal position, the back of the chaser being a little below
the center of the grinding wheel, which, for purpose of illustration, is shown as
about the same diameter as that of the pipe. Greater clearance may be ob-
tained by slightly raising the rest. When a grinding wheel somewhat larger than
the pipe diameter is used, the center of the chaser should be slightly above the
center of the wheel. The clearance may be reduced by lowering the rest, but
the chasers should always be held horizontal unless a specially designed jig
or fixture be used to hold the chaser at correct grinding angle.
912
Pipe, Fittings and Pipe Fitting
What is the technique?
Ans. It is placed in the pipe vise and a piece of pipe threaded
on one end screwed tightly into the coupling, and after cutting
off to length desired for the nipple, an attempt is made to
thread the other end.

a
↓ k k d
Figs. 103 to 106.-Results obtained in grinding chasers. Fig. 103, cutting edge
rounded off. No clearance in lead. Result of careless grinding and lack of
temper in steel of chaser; fig. 104, no clearance in throat or lead, caused by
grinding the lead at too low a point on the wheel; fig. 105, too much clearance
in thread or lead, caused by grinding at too high a position in relation to center
of grinding wheel. This causes the die to chatter with resulting rough wavering
thread, if not in fact stripping short pieces from the thread or breaking the chaser;
fig. 106, correct throat or lead.
CRACKS

END OF THREAD
Fig. 107.-Makeshift nipple holder as used by some alleged steam fitters. In
sending in the bill, the fact that the old time charcoal pots are out, is of no
consequence, as gasoline for the gas torch is listed instead, and at an even
more handsome profit.
Pipe, Fittings and Pipe Fitting
913
What happens?
Ans. Owing to the considerable effort required to cut the
thread, the nipple turns in the coupling until the latter is
strained to the splitting point and in fact usually does split
before many nipples have been cut in this way, resulting in
profanity and a waste of time.
How is the nipple removed from the coupling?
Ans. A nipple thus made is removed from the coupling and
die by the aid of a Stillson wrench and more profanity.
What is the plumber's reaction to this technique?
Ans. In sending in the bill, the waste of time and couplings
are of no consequence to an unscrupulous mechanic, for these
items are charged to the customer along with such things as
candles, waste, charcoal, oil, matches, etc., at a very handsome
profit.
What is a Stillson wrench?
Ans. A variety of monkey wrench having serrated (teethed)
jaws to enable it to grip a pipe or round surface, thus fitting it
to act as both the old fashioned pipe tongs and spanner.
How is an internal thread cut?
Ans. By means of a tap.
;
What is a tap?
Ans. A conical screw made of hardened steel and grooveď
longitudinally for cutting internal threads in nuts and the like.
The following table gives drill sizes which permit of direct
tapping without reaming the hole beforehand.
914
Pipe, Fittings and Pipe Fitting
Drill Sizes for Pipe Taps

Size Tap
Inches
Bel
1
All you nee
1/
/
И
་
K
1/
½
1
***
2
216
216
2%
3
31/12
314
3%
10
4162
5
514
•
7
BRIGGS STANDARD
RIGGS
Thread
27
18
18
14
14
....
11%
11/½
11
1114
*
co ed so
8
8
8
8
CXHAKLĒJUMUUA TAKLIMA
Drill
21/1
8744
14
11/4
11/4
...
14
11%
11/4
214
2%
3%
311/0
*4%
41%
·5%
6%
7%
81%
91%
10
BRITISH (Whitworth)
STANDARD
Thread
28
19
19
14
14
14
14
11
11
11
11
11
11
11
11
11
11
11
11
11
11.
11
11
11
Drill
3/4
A
//
31/0
$5/2
*/
11/4/
1½
115
11
111
2%
21/
21/
31/
3
31/14/1
31/2
41/2
4/2
51/2
5/2
61/2
7
81/%
9%
10%
Figs. 108 and 109.-Pipe tap
and pipe tap reamer.

Pipe, Fittings and Pipe Fitting
915
How may pipes be bent by hand without the use of
special tools?
Ans. Completely fill the pipe with dry sand and cap the ends
so the filling will be retained. Heat the part to be bent; clamp
the pipe in a vise as close to the part to be bent as possible.
Now cool the outside of the curve with water so that the inside,
being hot and plastic, is compressed as the bend is made.


CLAMP
LEG
STANDARD
PLACING CENTER PUNCH
MARK IN LINE WITH FEED
SCREW
FEED
SCREW
MOVABLE
ARM
JIITITTY
ARMS
WAAROLIITILZAMIKA).
606
(AMILLINE B
KHE
Whi
RADIAL
LINE
Figs. 110 and 111.-Pipe drilling crow and method of using. The crow consists
of two V arms and a leg forming a tripod support for the upright rectangular
post or standard. An arm is arranged to slide on the standard and is secured in
any position by the clamp. At the end of the arm is tapped a feed screw with
hardened point, which is directly over the line joining the apex of the V arms,
hence the point of the feed screw, when lowered, will touch the surface of a
pipe resing in the V arms at a point so located that the axis of the feed screw
passes through the center of the pipe. Moreover, the feed screw being per-
pendicular to the line joining the apex of the V arms, if a drill be applied at
the same point touched by the feed screw, and guided by the feed screw as in
fig. 111, the hole will be drilled radially and at right angles to the pipe axis.
When the required curve has been obtained how is it
retained while bending the other sections?
Ans. By cooling with water.
916
Pipe, Fittings and Pipe Fitting
Pipe
size
inches
111
1/8
4
1001~1001
3
8
3/4
-^^-^
114
11/2
2
*******
~
22
3
31/2
Center
to
face
2223445
Radii for Standard Wrought Steel Pipe Bends
(As recommended by National Tube Co.)

21/4
Ahuttin
22
314
NT ATUTAT
412
534
7
Advis-
15
18
21
able
radius
Mosby
CLEAT
Mini-
mum
radius
inches
11/4
13%
11/2
13/4
1223 M4
21
NTAL STATA
212
314
41/2
10
12
14
Pipe
size
inches
4
+700700=
*******88
41/2
5
6
8
9
10
Advis- Mini-
able mum
radius radius
inches inches
11
24
B
27
30
36
42
48
54
60
66
Pipe
size
inches
16 12
18 13
2343
METAL PLATE
20 14
24
28
32
36
40
44
CLEAT
15
GUIDE
18 O.D.
20 O.D.
22 O.D.
24 O.D.
Advis-
Mini-
able
mum
radius radius
inches inches
72
84
90
100
125
150
165
180
48
60
68
76
90
120
132
144

KELLELLIN
Fig. 112.-Ordinary method of drilling a pipe for tapping where a crow is not
available. One end of a lever is placed under the edge of a timber, as shown,
Pipe, Fittings and Pipe Fitting
917

G
A
U
F
B
A
C D
G7D
E
Figs. 113 to 115.-The noted "Gun" tap and character of its cut. This tap differs
from ordinary taps in that the cutting edges A, are ground at an angle B, to
the axis of the tap. This causes the tap to cut with a shearing motion, that is,
with the least resistance to the thrust. The angle of the flutes deflects the chips
so that they curl out and ahead of the tap and do not collect and break up in
the flutes. This action of "shooting" the chips ahead in long unbroken coils is
responsible for the name "Gun" given to the tap; fig. 115 shows this action,
which since it is non-clogging, the tap does not have to be backed out of deep
holes to clear collected chips from the flutes. Instructions for grinding: 1. See
that the abrasive wheel is shaped to fit the flute at G, (fig. 113) in order to
maintain the shape of hook exactly. 2. When the ends of the lands F, get thin
from continued regrinding, grind the end of the tap straight back until lands
reach normal thickness. 3. In regrinding chamfer or plugging C, be sure to grind
the relief, seeing that the cutting edge A, is the highest edge; gradually back-
ing away from this edge as shown by the circle at Č. 4. The last plugged thread
D, should be about two threads below the junction of the bevel and straight
flute. 5. Slightly round off any corner at junction of bevel and straight flutes E,
carefully. 6. Maintain this angle B, for shear cut. 7. In regrinding remove as
little metal as possible-merely enough to keep the cutting edges sharp and
maintain the original form.
Fig. 112.-Text continued.
while a helper bears down on the other end, sliding the lever in contact with ɑ
vertical timber, using it as a guide. When this plan is adopted it is not necessary
to operate the feed screw in the upper part of ratchet, as the lever follows it
down. This could not be done in the case of a deep hole, as the top of drill
would be carried out of place, but it is all right for drilling one or more holes
in a pipe as shown.
918
Pipe, Fittings and Pipe Fitting

Barat
ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ ÿ
Fig. 116.-Pipe bending vice. In bending, the pipe is threaded through the screw
eye and the pipe forced on the curved form.

E
MIG mydiluu aika
MANSOUTON
Fig. 117.-Bending block and pins. This is a simple method, but requires a care-
ful workman to get a smooth job, and though adaptable to the largest sizes of
pipe, may require a tedious amount of work. Two pins are required for the neces-
sary leverage to pull the pipe around. The plate is desirable for keeping the bend
in a true plane. In bending, the pipe is heated in a small spot at a time on the
inside of the bend, as shown in the shaded portion at E. If the heat extend
around the outside of the pipe, this should be chilled with water immediately
Pipe, Fittings and Pipe Fitting
919
Size
Ins.
18
ANT
པེཥ༦༠.༠
3/2
8
10
10
10
12
12
Threads and
couplings
Weight per foot
Lbs.
.86
1.14
1.70
2.30
2.75
3.75
5.90
7.70
Unlined Duro-Unlined Duro-
steel
steel line
pipe
pipe
pipe
Lbs.
line
pipe
45.45
SI.15
Lbs.
.98
1.30
1.93
2.71
Plain ends
3.24
4.62
6.96
9.28
Lbs.
.85
1.13
1.63
2.27
2.72
3.65
5.79
7.58
11.09
9.11
9.25
11.00 13.47 10.79
15.00 18.81 14.62
24.70
19.45 25.17 18.97
25.55 33.27
29.35 36.98 28.55
32.75 44.46 31.20
.97
1.29
1.91
2.68
NATIONAL DUROLINE PIPE
Dimensions and test pressures
Diameters
Thickness
❤
Duro-
Steel line
pipe
wall
Ins.
Ins.
.109 .0690
.113 .0690
.133 .0765
.140
.1025
.1025
.1435
3.20
4.53
· 6.85
9.15
10.95
13.26 .237
.258
.280
.18.43
.145
.154
.203
.216
.226
lining External
(aver-
age)
.1435 ·
..1715
Ins.
.840
1.050
1.315
1.660
1.900
2.375
2.875
3.500
4.000
Internal
Unlined
steel
pipe
Ins.
.622
.824
1.049
1.380
1.610
2.067
2.469
3.068.
3.548
4.026
5.047
6.065
Duroline inch
pipe
Ins.
1.175
1.405
1.780
2.182
Threads
per
.484 14
:686
.896.
2.725
3.205
3.620
4.548
9.443
9.387
Ins.
2/8
14 215,16
11/2 3.16
11/2
11½
35/8
3116
11½ 4%
8
5/16
8
8
5.440
8
7.446 8
7.356
8
Couplingst
Length
8
8
8
8
8
54
5%
5/2
516
616
1900
.1715
1700 1900
1600 1800
.2030
4:500
.2495 5.563
1400 1600
.3125
6.625
1300
.277 .3125
8.625
8.071
950
8.625
7.981
1100
24.70
32.41
36.18
.322 .3125
42.91
.279 .3745
35.75 47.39 34.24
45.88
.307 .3745
40.48
51.99 .365 .3745
43.77 57.74
.330 .3745
10.750
10. 192
800
10.750
850
41.85
53.35
1000
59.42
800
65. ΟΙ
49.56 63.43
900
10.136
10.750 10.020 9.271
12.750 12.090 11.341
375 3745 12.750 12,000
II.251
Furnished with threads and couplings and in random lengths, unless otherwise ordered. The I.D. of lined pipe is the nominal I. D. of
unlined pipe minus twice the average thickness of lining. Weights are theoretical, based on average thickness of lining and one cubic inch
of DUROLINE weighing .0845 pound. The weight per foot with threads and couplings is based on a length of 20 feet, including the cou-
pling. Galvanized DUROLINE Pipe is galvanized on the outside only. Coated or Copper-Steel DUROLINE Pipe can be furnished on
all of the above sizes. Data on larger diameter or heavier wall DUROLINE Pipe furnished on application.
*This size regularly furnished with line pipe thread length; standard pipe thread length should be specified where standard pipe fittings
are used..
Tests made on unlined pipe.
Threaded in accordance with standard practice and fitted with interlocking plastic sleeve.
External
diameter
616
616
Test pressuret
5.200
6.296
7.390
9.625
9.625
7/8
11.750
7%
11.750
7/8
11.750
7/2 14.000
1/2 14.000
Butt-
welded
Ins.
700
1.063
1.313 700
1.576 700
2.054 1200
2.200 1200
2.875 1200
3.375 1200
1200
4.000
4.625
Lap-welded
or seamless
Grade A
Seamless
Grade B
Lbs. per sq. in.
1000
1000
1000
1000
1000
1000
2500
2500
2300 2500
1900
2200
2100
2400
2100
1400
1100
1300
900
950
1200
900
1000
Fig. 117.-Text continued.
before bending, the object being to keep the outside cold to prevent flattening the pipe while the pressure
of the bending causes the inside to upset and so furnishes the shorter radius for the inside. Only a very small
portion of the pipe can be heated at a time and should the pressure cause the inside to start to kink at any
point, that place must be immediately chilled with water, and the bending continued further along. On
account of the constant shifting of the heat on a very small portion at a time, the use of an oil torch for heating
is a great advantage, as it saves carrying the pipe to and from a forge, but the latter can be used if necessary.

920
Pipe, Fittings and Pipe Fitting
In assembling, what do they mean by "make up"?
Ans. On large jobs the pipe is usually cut according to a
sketch or working drawing and partly assembly at the shop.
If no mistakes have been made in following the dimensions on

ANVIL
COUPLING
K
H
Figs. 118 and 119.—Anvil method of pipe bending. In fig. 118 a coupling and
short length of pipe are temporarily fitted on the end at the slat, as shown at F,
A short heat is taken close to the coupling at G, the pipe laid over the horn
of an anvil, and with a swage and sledge the bend is started, turning the pip
over on its side if necessary to work out any kinks or flattening that may occu
while this first bend is being made. The added section of pipe is then removed
and a quite different method continues the work, as shown in fig. 119. The
clamped band handle H, is now bolted on some distance back from the end,
and the pipe itself is suspended by a block and sling, so that it may be easily
raised and lowered as necessary, and must be hung from a support far enough
above it so that it may be swung pendulum fashion through a swing of three or
four feet. A heavy wood block I, for a "butting post" is leaned up against a
convenient anvil or wall, as shown. A short heat is then taken on the pipe just
beyond and adjoining the portion that was first bent. It is then swung like a ram
against the block, and the force of the blow acting on the tangent of the first
bend causes a continuation of the bending in this next section, while sufficient
upsetting of the material takes place at the same time so that there is no flatten-
ing down of the outside, and the pipe holds up to its full form. This same proce-
dure is continued for one section following another, and the pipe rolls up into
forms as shown at J, where in this case the shaded portion K, indicates the place
where the bending is taking place. Care must be used that the bend does not
run out of a true plane, and if there be any tendency toward doing so, the work
must be laid on a face plate or anvil and tuned up. In working with this method
and that of fig. 118, the smith must work up to an inside template which has
been made up for the radius of the inside of the bend, using care to keep each
added bend close to the template size to save any unnecessary bending or
straightening of the work later on when it might not be so easily performed
without reworking the whole piece.
Pipe, Fittings and Pipe Fitting
921
the drawing, and the latter be correct, the pipe and fittings
may be installed without difficulty, that is, the last joint will
come together or make up.
Of what does this last joint consist?
Ans. Either a union, a right and left, or long screw joint.

Eventu
SHINNES

TRIMO-A 14″
Figs. 120 to 122.–Various pipe wrenches.
What difficulty is encountered if errors have been made
in the dimensions?
Ans. It will be difficult or impossible to make up this closing
joint.
Incompetent fitters in such cases will try to force the joint together,
sometimes they succeed in making up the joint, bringing great strain
on the assembly and such work can well be called "a bum job."
On small jobs what do they do instead of cutting and
fitting by sketch?
922
Pipe, Fittings and Pipe Fitting
Ans. Usually "by eye," taking occasional measurement.
How do they put together screwed joints?
Ans. Red or white lead, graphite or some standard pipe
cement is used*.
PRESS HERË
A
C
JAWS SLACK
OH!
-411 Blaktas
IT
add_
।।
//1.
Ti
|_
do!
B

JAWS ON BITE"
Figs. 123 and 124.-How to use a pipe wrench. Adjust wrench so that jaws
will take hold of pipe at about the middle part of the jaws. To support wrench
and prevent unnecessary lost motion when wrench engages pipe, hold jaw at
A, with the left hand pressing it against the pipe. At the beginning of the
turning stroke B, with jaw held firmly against pipe with left hand, the wrench
will at once "bite" or take hold of pipe with only the lost motion necessary to
bring jaw C, in contact with the pipe.
What should be done before making up a screwed joint?
Ans. The threads should be thoroughly cleaned with an old
stiff tooth brush.
*NOTE.-The author's practice is half red lead pigment, half graphite mixed
with linseed oil, using no dryer if you expect to take down the line at some future
time.
Pipe, Fittings and Pipe Fitting
923
What is the secret of making tight joints?
Ans. 1, The threads should be clean; 2, the best lubricant
should be used to prevent friction; and 3, in making up the
joint it should not be screwed up fast enough to make any
appreciable change in the temperature of the metal.

PIECE OF GLASS
///
RED LEAD
ROLL ON
TABLE EDGE
firea
BRUSH WHEN
NOT IN USE
OLD TOOTH BRUSH
Fig. 125.-Method of applying red lead or other material to male thread with
an old tooth brush. The pipe is rested against the bench or other support and
turned by the left hand in the direction indicated by the arrow while the joint
material is applied with the brush as shown. It is unnecessary to put much
material on the threads, as it will be simply pushed out and wasted when the
joint is screwed up. It should, however, be put on evenly and cover all the
threads, care being taken not to let any touch the reamed end of the pipe where
it may get inside. The red lead is preferably obtained in the powder form and
mixed with oil and a little dryer at the time the pipe is to be made up. Get a
clean piece of glass on which to prepare the lead. The tooth brush should be
laid on the glass after applying the lead, to avoid getting grit on the brush
and paint on the table. When grit becomes mixed with the lead it prevents.
close contact of the filling and pipe thus making the joint less efficient.
Are especially long threads favorable for tight joints?
Ans. No.
Does the absence of heat in making up insure a tight
joint?
924
Pipe, Fittings and Pipe Fitting

Size
inches
1/8
Fig. 126.-Screwed joint made up showing length A, of thread on pipe that is
screwed into valves or fittings to make a tight joint, according to the following
table by Crane.
1/2
3/4
Dimen-
sion
A
inches
M
(Necessary to make a tight joint.
1/4
3/8
3/8
1/2
Length of Thread on Pipe
Size
inches
Just Jared Jack
1
14
11/2
FA
2
21/2
Dimen-
sion
A
inches
9/16
11/16
1516
Size
inches
Dimension A, fig. 126.)

PUMP CONNECTION FACE
3/2½
334
A
3&
LENGTH OF PIPE-
42
Dimen-
sion
A
inches®
1
116
16
11/8
13/16
Size
inches
6780ON
9
10
12
S
Dimen-
sion
A
inches
114
144
15/16
13/%
12
15%
15/16
20".
Fig. 127.-Detail of a feed line showing method of determining length of pipe A.
Length distance from pump connection face to elbow face + thread at M+
thread at S.
=
Pipe, Fittings and Pipe Fitting
925
•

HOT
WELL
150
FEED
PUMP
16
17
FIG. 128.-Center line sketch with dimensions for the method of pipe
fitting entirely by measurement. This should not as a rule be an elaborate
drawing, but simply a free-hand pencil sketch. Frequently such sketch
is made by the fitter when
beginning the job and serves
not only as a dimension sheet
but as a guide for the general
piping scheme which the fitter
has in mind. It should be
understood that with the mul-
tiplicity of fittings available
there are any number of ways
in which the piping may be
arranged and the fitter's ability
may be judged by the general
arrangement of piping which
he adopts.
-F
2'-1″
A
-1'-8″-
-3'-7!!
B
اند
2
FEED LINE
O
3
3'.
NOW!
MAKE UP LINE
341"
BY PASS
16!
7|-|
18
D
a
TJ 12 14
-2′
LINE
D
MAKE UP
JOINT
OVERFLOW
5"-
5
TANK
K 13
-2-5″
-3-
1842
TOO SHORT
HE
1013
101-
¢
191
6
FIGS. 129 and 130
2
Detail of feed line ready to "make up”. Fig. 129, shows poor
workmanship, nipple E, being too short rendering it difficult to bring together the make
up joint. Fig. 130, shows good workmanship; here the male end of the union will easily
spring back into position in making up the joint..
926
1
Pipe, Fittings and Pipe Fitting
Ans. No.
It should be understood that the absence of heat in making up does
not mean the absence of grit or gum in the threads.
Are perfect threads necessary to make tight joints?
Ans. No.
What is necessary for tight joints?
Ans. Clean threads and proper cement.


A
Man
F

A
H
DAN
UULUU
100
Figs. 130 to 140.-General dimensions of standard malleable iron screwed
fittings. The reference letters refer to the following table.
514
532
334
A
22
}}
General Dimensions Crane Standard Malleable Iron Secrewed Fittings.
24
1
Size Inches % 4 %
A..Inches
1/4 1/2 2 22 3 32 4 42 5
H H H 1 17 13% 118 24 2 3% 33% 4% 4%
34 17 % 1 136 1 1 1 1÷동 ​2곯 ​236 256 23
6
B...Inches
C. .Inches
8%
61
1
2½ 2% 3% 4% 4% 5% 6¼47¼
D. Inches
1층 ​222동 ​34 45
E..
Inches
1614 | 112 | 22|34 3층 ​4 46
F.. Inches 58.34 8 1 1 1 1 1 15% 134 13 2
G..Inches
11 12 13 14 2% 2% 2% 3%
H..Inches 1% 1 17 15% 1% 2% 22 2 3 31 42
K..Inches
12 12 1 1½ 1H 1% 2%
L.. Inches H│B│A | B |18|14 | 1% | 1}
3
2%
BULUI
A




22
6 7 8
5% 5% 6%
37 376 44
Non-Ferrous Tubing and Fittings 927
CHAPTER 47
Non-Ferrous,
Tubing and Fittings
Non-ferrous pipes and tubing here considered are those made
out of brass and copper. The advantage is that brass or copper
offers effective resistance to corrosion.
.
Mention another characteristic.
Ans. Hard drawn copper tubes will freeze and twist almost
the same as iron or steel pipes because they do not stretch freely,
however, the soft copper or annealed tubes do resist damage
rom freezing.*
}
Name a disadvantage.
Ans. Expansion and contraction.
This should be amply provided for in installations by allowing 50
per cent more than for iron for the same temperature rise.
What is the rule?
Ans. For 100 ft. of copper tube with a 100° Fahr. temperature
rise, allow slightly less than 1/4 inch.
*NOTE.-According to Thomson the soft tubes can stand freezing several times
before being burst. Tests have shown that ½ inch annealed tubes have been frozen
as many as six times before they finally burst, 8 times for 1 inch size and 11 times
for 2 inch size. Iron pipe and hard copper tubes subjected to the same test con-
ditions all burst during the first freezing.
928 ་
Non-Ferrous Tubing and Fittings
Sizes and Weights
of
COPPER WATER TUBES

Nominal
Size
Inches
1
114
11/2
2
3/8
1/2
58
21/2
3
1/8
14
312
4
นก
5
6
8
12
10
SIZES
Outside
Diameter
Inches
.250
.375
.500
.625
.750
.875
1.125
1 375
1.625
2.125
2.625
3.125
3.625
4.125
5.125
6.125
8.125
10.125
12 125
For Underground Services
and General Plumbing
Purposes Used with Solder
or Flared Fittings
Type K
Hard or Soft
Wall
Thickness
.032
.032
.049
.049
.049
.065
.065
.065
.072
.083
.095
.109
.120
.134
.160
.192
.271
.338
.405
Pounds
Per Ft.
.085
.133
.269
.344
.418
.641
.839
1.04
1.36
2.06
2.92
4.00
5.12
6.51
9.67
13.87
25.90
40.26
57.76
For General Plumbing
and House Heating
Purposes.
Used with Solder or
Flared Fittings
Type L
Hard or Soft
Wall
Thickness
.025
.030
.035
.040
.042
.045
.050
.055
.060
.070
.080
.090
..100
.110
.125
.140
.200
.250
.280
Pounds
Per Ft.
.068
.126
.198
.285
362
.455
.655
.884
1.14
1.75
2.48
3.33
4.29
5.38
7.61
10.20
19.29
30.04
40.36
For General Plumbing and
House Heating Purposes,
with Normal Water
Conditions. Used
with Solder Fittings only
Wall
Thickness
.025
.025
.025
.028
.030
.032
.035
.042
.049
.058
.065
.072
.083
.095
.109
.122
.170
Type M
Hard
.212
.254
Pounds
Per Ft.
.068
.106
144
.203
.263
.328
.464
.681
.94
1.46
2.03
2.68
3.58
4.66
6.66
8.91
16.46
25.57
36.69
Non-Ferrous Tubing and Fittings
929
What is the application of hard tubes?
Ans. They keep their shapes better than the soft tubes and
therefore are better adapted to exposed lines such as mains
hung from ceiling, etc.
What is the application of soft tubes?
Ans. They are well adapted for connections around machin-
ery such as that employed in air conditioning, refrigerating and
oil burning equipment, because they can be neatly bent to fit
around different portions of the machines.
Type K tubes are used for underground services, water, gas, steam
and hot water heating systems, oil lines, and for interior plumbing.
For gas services hard copper tube should be used as it must be stiff
enough to avoid the formation of traps in the lines.
Type L tubes are used for medium pressure interior plumbing and
for steam and hot water house heating systems.
Type M tubes are used for low pressure plumbing and for both low
pressure steam and hot water house heating systems.
How do copper and brass pipes differ from tubing?
Ans. Because they are used with threaded fittings they must
be made thicker than tubing.
How are they proportioned?
Ans. The same as ordinary wrought steel pipe.
Fittings for Brass and Copper Pipe and Tubing.-There
re several systems which are widely different in character.
The fittings may be classed:
1. With respect to material as:
a. Brass.
b. Copper.

930
Non-Ferrous Tubing and Fittings
2. With respect to construction as: a. Wrought.
b. Cast.
3. With respect to the method of joining as:
b. Flared (compression)
a. Screwed.
O
9LS
c. Solder edge feed
DIV
NOTE!
BRASS
PIPE
PorA
2
punter
ET
Fig. 1.-A good die stock for brass pipe. The center plate is brass and di
are marked for easy identification. Many plumbers make a practice of r
serving a set of iron pipe dies for threading brass pipe. To insure consistent
satisfactory results, it is very essential that the dies be maintained in god
condition and used for threading brass pipe only. The plumber will find man
advantages in using a die which is especially designed to conform with th
threading properties of brass pipe.
What advantages are claimed for wrought fittings?
Ans. Connections are better; expand and contract with tub
1. Screwed Fittings.
What is the technique with screwed fittings?
Ans. Same as with ordinary malleable iron fittings.
What should be noted about poorly tapped fittings?

Non-Ferrous Tubing and Fittings
931
Ans. Often when a fitting is not tapped deeply enough,
fitters are tempted to set the dies a little closer and cut the thread
on the pipe deep enough to suit the defectively tapped fitting.
This practice should be avoided. It weakens the pipe at a vital
spot and may be a cause of expense in adjusting claims for
faulty workmanship. It is better to select correctly tapped fit-
tings than to reduce the wall thickness of the pipe. See fig. 1.
C
=
Figs. 2 to 6.-A group of flared fittings cut away to show construction details.
In making up screw joints which kind of cement should
be used?
Ans. To insure a water tight joint, boiled linseed oil mixed
with red lead or graphite is very satisfactory for this purpose.
The mixture should be applied to the outside of the pipe and
ever to the inside of the fitting.

932
Non-Ferrous Tubing and Fittings
The latter method is apt to impart a disagreeable taste and color to
the water. An even more serious consequence, where the filler is applied
to the fitting, is the possibility of an irregular ring formation on the
SUIT
M|| ||]
Molo|||}}
Fig. 7.-Double seal type of flared joint,
זיון
inside of the pipe joint when the assembly is made. If the compound
should harden, this obstruction will seriously interfere with the flow
of water.

Non-Ferrous Tubing and Fittings
933
Fig. 8.-Making a flared joint 1. Cutting tube to exact length using a guide
to insure a square cut.
Chikakood fool aniprall
ning A frioj bose
a enideM-
Fig. 9.-Making a flared joint 2. Removing all burrs and sleeves by filing
both inside and outside. ammert si lo ewald wat o daw ylizos bangs diw

934
Non-Ferrous Tubing and Fittings
Fig. 10.-Making a flared joint 3. Slipping coupling nut over the end of
tube and inserting the flanging tool.
ban
Fig. 11.-Making a flared joint 4. Driving the flanging tool into the tube
expanding it to the proper flare for the style of fitting to be used. Soft tubes
will expand easily with a few blows of the hammer.

Non-Ferrous Tubing and Fittings
935
2. Flared (Compression) Tube Fittings.
What kind of fittings are used for flared soft tube end
t tube end
OHTA
joints?
foror
lime-noble
bleing, and
me
iqque bus
bus nobrezianos 3d
Ans. Cast fittings.
virpack
Fig. 13.-Flanging tool.
Fig. 12.-Making a flared joint 5. Assembling the fitting, which is tightened
by using two wrenches, one on the nut, the other on the body of the fitting.
eat
Hant
m

936
Non-Ferrous Tubing and Fittings
sign)
n
Where is this system used? ou and abuit to ball JCHW
Ans. There is a definite field of application particularly for
fire sprinkler systems and underground lines such as water and
domestic gas services, oil burner construction and supply lines,
etc.
What fittings are available?
Danstilpit
Fig. 14.-Sizing tool.
pit
Ans. The complete line includes elbows, tees, couplings,
unions, and a full range of reduction and adapter combinations
in all standard sizes and combinations of sizes from one-eighth
into two in. inclusive. See figs. 2 to 6.
loot phipholteit

Non-Ferrous Tubing and Fittings
937
EDGE AND END FEED FITTINGS
97omert has wre
tol plenusipe foo univtall pluie f
verfeinerolod
o dis
old 11 aldr
TU
in odur
ANDCONY
Fig. 15.-Cast bronze edge feed solder fitting.
7/1
Juls Bid 20 79
B0779
Fig. 16.-Seamless wrought copper end feed solder fitting.
yule no
:sult rolinur
T
no)
01/11961 ST
Ban 84
78
WRIT
bat

938
Non-Ferrous Tubing and Fittings
What are the operations in making a flared joint?
remed joint? 2
Ans. 1, Cut off tube with hack saw and remove burrs; 2, slip
on sleeve nut before flaring; 3, strike flanging tool squarely for
uniform flare; 4, flared joint should seat freely before tighten-
ing. These operations are in detail as follows:
1. Cutting off. Cut the tube to the length required with a hack saw
(32 teeth to the inch). Make certain that the tube ends are cut square.
Figs. 8 and 9. Special vises with saw guides are readily available. If the
Figs. 17 to 23.-Various edge and hole feed solder fittings showing tube fit
and shoulder. In figs. 21 to 23, note holes for hole feed.
size and gauge of the tube do not permit the use of a disc cutter, cut the
tube to the length required with a hacksaw (32 teeth to the inch). Make
certain that the tube ends are cut square. Special vises with saw guides
are readily available. If the size and gauge of the tube permit the use
of a disc cutter, the cuts will be square and clean, requiring a minimum
of preparation for flaring. Ream the inside of the tube and remove burr
on the outside.
2. Flaring. Slip the sleeve nut section of the fitting over the end of
the tube before flaring as in fig. 10, then insert the correct size flanging

Non-Ferrous Tubing and Fittings
939
tool into the tube end, being careful that it is correctly centered. (It
is good practice to lubricate this tool with a drop of oil before driving
it into the tube.) Drive the flanging tool with a hammer, as in fig. 11,
striking it squarely in the center, until the tube is flanged to the outside
diameter of the tool.
Fig. 24.-Making an edge feed solder fitting joint 1. The outside of the
tube, for the distance it will be covered by the fitting, is cleaned and burnished
with steel wool or sand cloth to insure a proper flow of the solder.
3. Assembling. Inspect the surfaces of the connection for cleanli-
ness; insert the male section of the fitting into the sleeve nut and draw
tight with a wrench, as in fig. 12. Avoid springing the tube or putting
undue strain on the fitting.
3. Solder Fittings.
How do solder fittings come?
Ans. Usually in cast bronze and wrought copper.
nidoM-dr

940
Non-Ferrous Tubing and Fittings
Fig. 25.-Making an edge feed solder fitting joint 2. The fitting is thor-
oughly cleaned with steel wool or sand cloth as far as the shoulder, so that all
tarnish is removed and the solder will sweat-in for the full depth of the joint.
Fig. 26.-Making an edge feed solder fitting joint 3. Flux of an approved
type for the kind of solder being used, is applied by a brush to the outside of
the tube and the inside of the fitting, covering the socket completely.

Non-Ferrous Tubing and Fittings 941
What is the basic principle of solder fittings?
Ans. The natural law of capillary attraction. Tests have
demonstrated that solder can be fed by means of capillary
attraction vertically upward between two closely fitted tubes
Fig. 27.-Making an edge feed solder fitting joint 4. The tube and fitting,
being properly fluxed, are assembled and heated to the correct soldering tem-
perature by playing the torch on the fitting and the tube adjacent thereto.
Then solder is applied at the edge of the fitting and melting, flows by capillary
action into the space between the tube and fitting. bro milooo
Cide

942
Non-Ferrous Tubing and Fittings
to a height many times the distance required to make a solder
joint, regardless of the size of the fittings.
125 19 blo
What two kinds of fittings are used?
Fig. 28.-Method of applying solder to a hole feed fitting. With this type of
fitting, which has a feed hole for the solder and a groove inside, the procedure
is just the same, except that solder is fed into the feed hole until it appears as
a ring at the edge of the fitting. Be sure the hole is kept full of solder as it
shri.iks on cooling and solidifying.
Non-Ferrous 1ubing and Fittings
943

APPROXIMATE DELIVERY OF COPPER TUBES IN U. S. GALLONS PER MINUTE
PRESSURE
DROP
(lbs.)
5
10
20
30
40
50
PRESSURE
DROP
(lbs.)
5
10
20
62885.
30
40
50
S
34
10
S
70
100
150
180
220
240
3
11/4"
L
0.7
1.0
2.0
2.5
2.7
3.0
L
204008
30
60
70
S·
6
10
14
16
18
20
S
100
150
215
275
310
350
1/2
1/2″
L
234567
L
35
50
75
95
115
130
S
10
17
24
30
36
42
S
200
325
500
600
700
800
5/8"
2"
· L
357
9
11
13
L
75
110
165
200
250
280
S
14
2335
35
45
55
65
· S
400
600
900
1100
1300
1500
3/4"
21/2"
L
5
11
14
17
20
L
150
225
300
350
450
500
S
35
50
70
90
100
110
S
700
1000
1500
1800
2200
2500
1″
3″
NOTES: Columns marked S give deliveries through short lines, such as branches 15-ft. or shorter.
Columns marked L give deliveries through lines approximately 100 feet long.
L
11
17
25
30
35
40
L
200
300
500
600
700
800
944
Non-Ferrous Tubing and Fittings
Ans. The edge feed fitting and the hole feed fitting. See
figs. 17 to 23.
What are the operations in making a solder fitting joint
with edge feed fitting?
Ans. 1, Cut tube to length; 2, remove burrs from inside and
outside edges; 3, clean both fitting and tube with steel wool as
in fig. 24; 4, apply soldering flux on tube end, fig. 26; 5, revolve
fitting to spread flux evenly; 6, apply heat to the fitting, testing
with solder; 7, feed solder at the edge of the fitting, as in fig. 27
Steam Engines
945
CHAPTER 48
Steam Engines
What is a steam engine?
Ans. A machine for converting heat into mechanical power.
What is the basic principle of a steam engine operation?
Ans. In the steam engine, heat in the steam accomplishes
work only by being "let down" from a higher to a lower tem-
perature. In this process some of the heat is converted into
useful work.
How much?
Ans. Very little, more or less depending upon the type of
engine.
What are the essential elements of a steam engine?
Ans. 1, A piston to which steam under pressure is applied;
2, valve gear to "distribute" steam to and from the cylinder;
3, transmission gear to transmit and transform the reciprocating
motion of the piston into rotary motion to turn a shaft.
Name the kinds of parts necessary in a steam engine.
Ans. 1, Stationary; 2, reciprocating; 3, revolving.
F
946
Steam Engines
STUFFING BOX
PISTON ROD
CYLINDER HEAD
CYLINDER
FRAME
OR BASE
FOUNDATION
FLY WHEEL
CROSS HEAD
GUIDES
WRIST PIN
ECCENTRIC ROD
CRANK PIN
CONNECTING ROD
↓
ECCENTRIC
ECCENTRIC
STRAP
Fig. 1.-Elevation showing parts of a horizontal steam engine. As shown, the engine is mounted on a sub-
stantial frame or base, to which is boited at one end, the main bearing and at the other, the cylinder,
being connected by a vertical flange projecting from the top of the frame. The figure shows the general
arrangement of parts.

Steam Engines
947

STEAM PASSAGES
STEAM CHEST
STEAM INLET
VALVE
VS
M
S
THE %%
E S
CV
A
CYLINDER
PISTON ROD
PISTON
CYLINDER HEAD
CHEST COVER
EXHAUST PASSAGE
R
STUFFING
BOXES
VALVE STEM
IT
•
G
CROSS
HEAD WRIST
PIN
ECCENTRIC ROD
ECCENTRIC
CONNECTING ROD
BASE OR FRAME
•
CR E
S
CRANK PIN
FLY WHEEL
к
K
FLY WHEEL
BEARING
SHAFT
BEARING
:
Fig. 2.-Plan showing parts of a horizontal steam engine, with names of same. The numerous parts may be
classified as: 1, stationary; 2, reciprocating; 3, rotating. Thus, 1, the frame, cylinder, cylinder heads,
valve chest cover, stuffing box guides, and main bearing are stationary parts; 2, the piston, piston rod,
cross head, wrist pin, valve, valve stem, eccentric rod, eccentric strap are reciprocating parts; 3, the
fly wheel, shaft, eccentric, are rotating pars. The engine here shown may be classed as a simple slide valve
horizontal engine.
948
Steam Engines
What are the stationary parts?
Ans. A cylinder, frame, and bed plate, as shown in fig. 1.
What are the reciprocating parts?
Ans. Piston, piston rod, cross head, connecting rod, valve
and valve gear.

13:
final
1010501
JA SYIKI
REVERSE LEVER

120
JAID
1180
IM BIN
001+297)
GEOME
SONG TITLEME
What are the revolving parts?
Ans. Shaft and eccentric.
SECTION
THROUGH
A B
A
B
B
REVERSING VALVE
1194
1
Fig. 3.-Graham special two cylinder, double acting, transfer expansion jacket-
ted oscillating marine engine, with feed and air pumps attached and ball
thrust bearing. The object of showing this engine is to illustrate the oscillating
type. Oscillating engines are used principally as deck capstan engines, com-
monly called "nigger" engines.
-
Describe the cylinder.
Ans. It consists of a cylindrical chamber as shown in fig. 2,
bored true and in which is fitted a steam tight piston, free to
move from one end to the other. There is a steam passage at
each end of the cylinder terminating in steam ports at the valve
Steam Engines
949

וןסןןן
L
seat. These passages converge cen-
trally toward the exhaust passage.
The valve seat forms part of a box-
like chamber in which is the valve.
Describe the operation of the
engine.
Ans. As the piston moves, the
valve opens the steam port to its
full extent and closes it before the
stroke is completed, thus cutting off
the supply of steam. During these
"events" of the power stroke the ex-
haust cavity of the valve connects
the other steam port with the ex-
haust port, allowing the steam which
was admitted during the previous
stroke to exhaust into the atmos-
phere or condenser, according to
whether the engine be run non-con-
densing or condensing.
O
I
Figs. 4 to 10.—Diagrams showing several positions of the piston, valve, crank
and eccentric during one stroke. The diagrams show the relative movements
of the parts, the crank and eccentric positions being shown at the right.
These passages, valve, valve gear,
etc., are plainly shown in the illus-
trations.
950
Steam Engines
What is the effect of cutting off the steam?
Ans. Cutting off the supply of steam to the cylinder before
the piston completes the stroke causes the steam in the cylinder
to expand until the piston has almost completed the stroke.
How is it released?
A
100
90
80
SCALE OF ABSOLUTE PRESSURE
50
30
70
60
L40
20
14.7
10.
T
ADMISSIONA
F
ADMISSION
M
STEAM
100 LBS.
PRESSURE
B
RELEASE
EXPANSION CURVE
ន
ATMOSPHERIC LINE
EXHAUST
E
¡VACUUM LINE OR LINE OF NO PRESSURE
ATMOSPHERIC PRESSURE 14.7 LBS.
Sa
3
G

U BUDD
---
WE ARE QUE CDMA-20 mt man 40 GRAND CO-SOME CLAD IN 200.00
1Q
RELEASE
D
SCALE OF VOLUME
Figs. 11 and 12.-Theoretical diagram of cylinder showing the theoretical
advantage of using steam expansively. FA, AB, admission; BC, expansion;
CD, release (drop); DF, exhaust; FD FE, expansion ratio. See fig. 23.
Steam Engines
951
Ans. By the valve connecting the proper steam port with the
exhaust port.
What is the effect of expanding the steam?
Ans. It results in a given amount of steam doing more work,
thus increasing the efficiency of the engine.
What is the law of the expansion of a perfect gas at con-
stant temperature?
Ans. It varies inversely as its volume.

-THEORETICAL DIAGRAM
„ACTUAL DIAGRAM
LOSSES
Fig. 13.-Comparison of theoretical and actual diagrams illustrated by solid
black section losses in the actual engine which reduce the theoretical gain due
to expansion.
Does steam expand according to Boyle's law?
Ans. No.
Why?
Ans. It departs considerably from Boyle's law, especially at
early cut offs where the effects of condensation (which lowers the
pressure) and re-evaporation (which raises the pressure) are
marked.
952
Steam Engines

!
•
■
7 CUT OFF
44 CUT OFF
40 CUT OFF
803898 00
annosay Sen
Figs. 14 to 16.-Diagrams illustrating various cut offs. Fig. 14, six-tenths cut off, standard for marine en-
gines; fig. 15, one-fourth cut off, ordinarily the most economical for stationary non-condensing engines;
fig. 16, one-seventh cut off, ordinarily most economical for stationary condensing engines. In the diagrams
the compression curves are
shown.
not
What is the basis for general
calculation?
Ans. Boyle's law modified by a
"diagram factor."
What is the initial pressure?
Ans. The pressure at which steam
is admitted to the cylinder.

Why is the initial pressure always
less than the boiler pressure?
Ans. Because of the resistance of-
fered to the flow of steam through
the steam pipe, engine ports and
passages.
What is this loss of pressure
called?
Ans. Drop.

What is the number of expan-
sions and how expressed?
Ans. The degree in which steam
is expanded, expressed in terms of
the original volume.
Thus four expansions mean that steam
has been expanded to a volume four
times as large as its original volume.
Steam Engines
953
Upon what does the number of expansions depend?
Ans. Upon the real cut off, not the apparent cut off (later
explained).
What is the terminal pressure?
AL
INITIAL
PRESSURE
CUT OFF
¡

;
1
F
g. 17.-Diagram illustrating initial pressure. This is the pressure in the
cylinder at the beginning of the stroke and on the theoretical
diagram is assumed to remain constant up to the point of cut off.
Some initial pressures: Atmospheric engines, O lbs. gauge; low pressure
engines, 20 lbs.; early walking beam marine engines, 25 lbs.; later types 50
to 75 lbs.; stationary engines, 50 to 250 lbs.; marine screw engines, 80 to
250 lbs.; locomotives, 150 to 300 lbs. or more; locomobiles and special
engines, 250 to 500 lbs.
Ans. If steam be expanded to the end of the stroke, the pres-
are at that point is the terminal pressure.
Terminal pressure equals the initial pressure divided by the number
of expansions.
1
954
Steam Engines

11
C'
A'
A
M
CLEARANCE LINE
D'
D
ADMISSION
STEAM LINE
COMPRESSION
STROKE
Fig. 18.—Diagram illustrating terminal pressure. The terminal pressure may be
defined as the imaginary pressure that would exist in the cylinder at the end
of the stroke if the steam were expanded to this po'nt instead of being pre
released. Some terminal pressures: Single cylinder non-condensing, 25 to 20
lbs.; abs. condensing, 20 to 12 lbs.; multi-cylinder condensing, 12 to 5 lbs. abs
TERMINAL PRESSURE
PRE-RELEASE
PRESSURE
EXPANSION LINE
EXHAUST LINE
VACUUM LINE
Pi
B'
LOSS DUE TO
PRE-RELEASE
ATMOSPHERIC LINE
RELE
Fig. 19.-Theoretical indicator diagram illustrating the various "lines" of th
diagram.

Steam Engines
955
8 8 8 8
60
50
40
30
20
14.7
10
S
Lom
EXHAUST LINE
ATMOSPHERIC LINE
ZERO LINE
TERMINAL PRESSURE
ig. 20.-Diagram illustrating effect of expanding to a terminal pressure less
than the exhaust pressure. In the above card, representing non-condensing
operation, steam is expanded to A, below the exhaust line, giving the nega-
tive area Ś, which must be subtracted from M, to obtain the effective work area.
Kit
S
S
#
L
igs. 21 and 22.-Theoretical diagrams illustrating mean effective pressure.
The mean effective pressure must depend on the difference of the two areas,
M-S, or M' as shown in fig. 21, when the back pressure is constant.
Where compression is taken into account, as in fig. 22, evidently M. E. P.-
mean forward pressure mean back pressure, but in the figure,
the mean back pressure is figured from area Starea S', hence, in this case
M. E. P. depends on the difference between area M+S in fig. 21 and
areas S+S' in fig. 22, and giving the area M" where average ordinate X
pressure scale =M. E. P. In fig. 21 M (= entire area) M+S.
-
956
Steam Engines

A
A
A
B
Co
PRE-ADMISSION LOSS
Ε'
E
M+S = I + HYPERBOLIC LOGARITHM
COMPRESSION I
LOSS
S
Fig. 23. Reproduction in part of fig. 11, showing the application of the
hyperbolic logarithm in finding the mean effective pressure. Admission ared
= unity;
area hyperbolic
total area = 1 +
hyperbolic logarithm, and don't forget, the diagram shows very graphically
the meaning of 1 + hyp. log.
=
HYPERBOLIC LOGARITHM
-LOSS BETWEEN BOILER AND ENGINE
B
ADMISSION LOSS
·


LOSS DUE TO DROP AT CUT OFF
AND CONDENSATION
RE-EVAPORATION GAIN
EXHAUST LOSS
PRE-RELEASE
LOSS
יס
с
INITIAL
EXHAUST
LOSS
ATMOSPHERIC LINE
ZERO LINE
Fig. 24.-Comparison of theoretical and actual cards showing the various losse
which tend to reduce the area of the actual card, making it in some case
considerably less than that of the theoretical card. In the figure, ABCDE
is the theoretical card and A'B'C' D' E' F, the actual card..
Steam Engines
??
No.
Table of Hyperbolic Logarithms


1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
Hyp. log. No. Hyp. log. No.
0.0953
4.5
0.1823
4.6
0.2624
4.7
0.3365
4.8
0.4055
4.9
0.4700
5.0
0.5306
5.1
0.5878
5.2
0.6419
5.3
0.6931
5.4
0.7419
5.5
0.7885.
5.6
0.8329
5.7
0.8755
5.8
0.9163
5.9
0.9555
6.0
0.9933
6.1
1.0296
6.2
1.0647
6.3
1.0986
6.4
1.1312
6.5
1.1632
6.6
1.1939
6.7
1.2238
6.8
1.2528
6.9
1.2809
7.0
1.3083
7.1
1.3350
7.2
1.3610
7.3
4.0
1.3863
7.4
4.1
1.4110
7.5
4.2
1.4351
7.6
4.3
1.4586 7.7
4.4 1.4816 7.8
1.5041
1.5261
1.5476
1.5686
1.5892
1.6094
1.6292
1.6487
1.6677
1.6864
1.7047
1.7228
1.7405
1.7579
1.7750
1.7918
1.8083
1.8245
1.8405
1.8563
1.8718
1.8871
1.9021
1.9169
1.9315
1.9459
1.9601
1.9741
1.9879
2.0015
2.0149
2.0281
2.0412
2.0541
7.9
8.0
8.1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
8.9
9.0
9.1
9.2
9.3
9.4
9.5
9.6
9.7
9.8
9.9
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
15.0
16.0
17.0
18.0
Hyp. log. No.
2.0669
19.0
2.0794
20.0
2.0919
21.0
2.1041 22.0
2.1163
2.1282
2.1401
2.1518
2.1633
2.1748
2.1861
23.0
24.0
25.0
26.0
27.0
28.0
29.0
30.0
31.0
32.0
33.0
34.0
35.0
36.0
37.0
Hyp. log.
2.9444
2.9957
3.0445
3.0910
3.1355
3.1781
3.2189
3.2581
3.2958
3.3322
3.3673
3.4012
3.4340
3.4657
3.4965
3.5263
3.5553
3.5835
3.6109
3.6376
3.6636
2.1972
2.2083
2.2192
2.2300
2.2407
2.2513
2.2618
2.2721
2.2824
38.0
2.2925
39.0
2.3026
40.0
3.6889
2.3513 41.0
3.7136
2.3979
42.0
3.7377
2.4430
43.0
3.7612
2.4849
44.0
3.7842
2.5262
45.0
3.8067
2.5649
46.0
3.8286
2.6027
47.0
3.8501
2.6391
48.0
3.8712
2.7081
49.0 3.8918
2.7726 50.0 3.9120
2.8332
2.8904
NOTE.-Hyperbolic or Naperian logarithms are common logarithms multiplied by
2.3025851.
Rule. To find the mean effective pressure, multiply the initial
pressure in lbs. absolute by 1+hyp. log. of the number of ex-
pansions, and divide by the number of expansions. From the
quotient, subtract the absolute back pressure.
In the form of an equation the mean effective pressure or
958
Steam Engines
M.E.P.
=
initial pressure abs. × (1+hyp. log, no. of expansions)
number of expansions
or, expressed in the usual symbols
M.E.P.=
P× (1+hyp.log. r)
r
It should be remembered that the initial pressure P, and
back pressure (B.P.) are taken in lbs. absolute.
Number of expansions=1÷1=1X³/1=3.
Hyp. log. of 3 (from table page 957)=1.0986.
1+hyp. log 3=1+1.0986=2.0986.
Example.-What is the mean effective pressure, with 80 lbs. initial
gauge pressure, one-third cut off, 16 lbs. absolute back pressure?
Initial pressure absolute=80+14.7=94.7 lbs.
94.7 X 2.0986
3
Diagram Factors
-B. P.
Mean effective pressure=
back pressure abs.
· ↑
16=50.2 lbs.
Diagram Factor
Particulars of Engine
.94
.9
.9 to .92 .86 to .88
.8 to .85 .77 to .82
Expansive engine, special valve gear, or with a
separate cut off valve, cylinders jacketed..
Expansive engine having large ports, etc., and good
ordinary valves, cylinders jacketed..
Expansive engines with the ordinary valves and gear
as in general practice and unjacketed..
Compound engines, with expansion valve to H. P.
cylinder; cylinders jacketed, and with large
ports, etc..
Compound engines, with ordinary slide valves,
cylinders jacketed, and good ports, etc..
Compound engines as in general practice in the
merchant service, with early cut off in both cylinders
without jackets and expansion valves...
Triple expansion engines, with ordinary slide valves,
good ports, unjacketed, moderate piston speed......65 to .7
Fast running engines of the type and design usually
fitted in war ships..
.7 to .8
.6 to .7
.9 to .92 .86 to .88
.8 to .85 .77 to .82
.67 to .77
.62 to .67
.58 to .67
Steam Engines
959
-CLEARANCE
ACTUAL CUT OFF
CURVE
APPARENT CUT
OFF CURVE
Kama MMDAN
E
Ε
E';
Ε
Figs. 25 and 26.-Diagrams illustrating the diagram factor. In fig. 25, the theoretical diagram,
A B C D E does not consider clearance and compression; it may be for certain purposes modified to allow
for these items. Thus, in the figure, not considering clearance, the admission would be represented by A B,
giving the expansion curve B C. Now taking clearance and compression into account, if c A, represent the
clearance volume, then admission would be represented by c B, instead of A B, giving the expansion curve
B C' above BC. By measurement the area of the actual diagram M, fig. 26, is 1.47 sq. ins.; the theoreti-
A B C D E A,= 1.8 sq. ins., and the modified theoretical card A B C' D E' A,=1.84 sq. ins. From which
cal card the diagram factor referred to theoretical card=1.47÷1.8.82, and referred to the modified
theoretical card=1.47÷÷1.84.799
What is the mean effective pressure?
Ans. The mean forward pressure acting on one side of the piston minus the mean
back pressure acting on the opposite side of the piston, abbreviated m.e.p.
What is a stuffing box?
Ans. A device affording passage and lengthwise or rotary motion of a piece, without
leakage, as of a piston rod, or globe valve stem.


960
Steam Engines
How is leakage prevented past a piston?
Ans. By means of piston rings.
What is a piston ring?
Ans. A ring fitting into a groove in the circumference of a
piston and pressing against the cylinder walls so as to form a
tight sliding joint.


U
O
a
и
IEJ
floni
ISI
COOTER WHERE
作
​ATEN
REZE
Figs. 27 and 28.-Stuffing box which forms a steam tight joint for the piston
or valve stem. By means of the adjustable sleeve, the proper pressure is
brought to bear on the packing to prevent leakage of the steam- P, piston
rod; B, box; T, gland; N, adjusting studs; U, gland flange,
SNAP RINGS

Fig. 29.—"Snap" piston rings. First used by Ramsbottom, an English engineer,
and sometimes called "Ramsbottom's rings." They are turned somewhat larger
in external diameter than the bore of the cylinder, and after being cut across
so that they may be compressed to fit the cylinder bore, are fitted into recesses
turned in the piston face.
Steam Engines
961

SNAP RINGS
EXTENDED FOLLOWER
Fig. 30.-Snap rings fitted to extended follower. This permits removal of rings
without taking out the piston.

לןן
о
|_ | | | |||||||
Figs. 31 and 32.-Mode of turning snap rings to secure uniform pressure along
the circumference. The ring is cut at the thinnest section.



MSU
Figs. 33 to 35.-Different methods of cutting snap rings.
T
962
Steam Engines
Describe a piston rod.
Ans. A steel rod working through a stuffing box in the
cylinder head and fastened to the center of the piston at one
end and to the cross head at the other end.
What does the piston rod do?
Ans. It transmits the force or pressure exerted upon the
piston to the cross head.

13
Figs. 36 and 37.-Large built up piston secured to the piston rod by means
of a key.
How is the piston rod connected to the piston?
Ans. In various ways as by: 1, Shoulder and shrink fit;
2, taper and nut; 3, taper key, etc.
How is the rod connected to the cross head and why?
Ans. Usually by threaded end with nut which allows for
adjustment to equalize the linear clearance.
Steam Engines
963
!
What is a cross head?
Ans. A "sliding hinge" which joints the piston rod to the
connecting rod.
The design of the cross head varies more than any other detail of the
engine.
*
What is the pivot in the cross head called and what is its
function?
M


a
B
ועשת
*-*-*
{D}}}
N
Z
TE
W
S
Figs. 38 and 39.-Cross head and wrist pin. The wrist pin W, is inserted in
holes bored through the jaws B and C, and the pin is secured by the nut Z.
M and S, are the gibs, which bear on the guides, and N, the neck to which
the piston rod is fastened.
Ans. The wrist pin (objectionably called cross head pin). It
imparts the movement of the piston rod to the connecting rod.
What is necessary for the proper working of the cross
head and why?
Ans. Guides to resist the lateral thrust, due to the angularity
of the connecting rod.
964
Steam Engines

RUNNING OVER
PRESSURE AND WEAR
ON LOWER GIB
RUNNING UNDER
Figs. 40 and 41.-Diagrams illustrating the terms "running over" and "running under" used to indicate the
direction of rotation of an engine. Since the weight of the crosshead and connecting rod continually cause
the lower gib to remain in contact with the guide when the wear is not fully taken up, if the engine run
under the crosshead is suddenly thrown against the upper guide after passing the center,
tending to cause a
as in fig. 41,
knock,
which
if the
engine
be
run over would be avoided.
rotary motion of the crank.
motion (of the piston rod) into
Ans. It converts reciprocating
the cross head?
What duty is performed by
PRESSURE AND WEAR
ON UPPER GIB
etc.
adjustment of inclined surfaces,
serting paper liners; 2, screw
ing to construction as by: 1, In-
Ans. In various ways accord-
up?
How is wear on the gibs taken
tion between dissimilar metals.
Ans. Because there is less fric-
guides?
different from that of the
Why are gibs made of a metal
Ans. The gibs or "slippers".
against the guides?
provides the rubbing surface
What part of the cross head


Steam Engines.
965
•
How would you define a connecting rod?
Ans. A rod which connects the wrist pin to the crank pin,
provided with enlargements at each end forming wrist pin and
rank pin bearings.
What are the bearings sometimes called and why?
AN
HH
ND
8060060 0
B'ob ó a bo
스
​Fig. 42.-Locomotive cross head with single guide. On locomotives the piston
rod is usually attached to the cross head by means of a key K. B, B', are
the gibs, and A, the guide whose outer end is bolted to a transverse piece
or yoke Y.
A
бо
.__O
A
Fig. 43.-Locomotive cross head with double guides.
目
​HA
966
Steam Engines
Ans. "Brasses". Because they are usually made of brass and
usually lined with Babbitt metal.
What is Babbitt metal?
OH
H

VEELALAA
Ľ
ΟΙ
DANNY NOORA

O
Figs. 44 and 45.-Block adjustment type connecting rod. The type generally
used on slow and medium speed engines. The rod of circular section tapers
from the middle to the forged ends which contain the crank and wrist pin
brasses. As constructed, one adjustment lengthens the rod, while the other
shortens it, the combined effect is to keep the length the same.


Figs. 46 and 47.-Key adjustment type connecting rod. This form of rod is
used in high speed engines. The rectangular cross section, and the pronounced
sidewise taper is the best shape to resist the severe bending strains due to
high rotative speed.
1
Steam Engines
967
Ans. A name loosely given in the United States to any kind
of white alleged anti-friction metal.
What is the criticism of the term anti-friction and why?
Ans. Ridiculous, because there is always friction between
rubbing surfaces.
How are the rod ends made?
Ans. Solid or built up.
A
B F

O
舘​0000007
G
"W

D
Figs. 48 and 49.-Solid end with block adjustment. The parts are: A, B,
brasses, A being provided with flanges C, D, E, adjusting block or wedge;
F, G, adjustment bolts which retain the block in the desired position.
How are the brasses adjusted to take up wear?
Ans. By means of 1, liners or "shims"; 2, block; 3, gibs and
cotters, etc.
How is the length of a connecting rod measured?
Ans. Between centers, that is, the distance between the wrist
bin and crank pin centers.

968
Steam Engines
อ
H
C B
A
G
E
F
Figs. 50 and 51.-Marine connecting rod with forked end and double bearing
For the wrist pin. To the T end A, is attached the brasses B, C, and cap D, by
the bolts E and F.
с в
777
F
I
G
E
A
:0
D
Figs. 52 and 53.-Built up connecting rod with gib and cotter adjustment
The parts are: A, stub end of rod; B and C, brasses; D, strap; È and F
cotters; G, gib; H, set screw.
Steam Engines
969
How long is the connecting rod?
Ans. It is usually from two to two and a half times the length
of the stroke.*
Where are short connecting rods used and why?
Ans. In marine practice to reduce the center of gravity of the
engine.
What is a "gudeon"?
Ans. An obsolete name for a wrist pin.
PRESSURE
ON PISTON
PRESSURE
ON GUIDE
A
PRESSURE ON
CONNECTING ROD
Db.
CONNECTING ROD
!GUIDE
C

B
CRANK
Fig. 54.-Parallelogram of forces showing the two component forces at the
cross head due to the thrust of the piston. By means of this diagram the pressure
on the guides and on the crank pin can be obtained.
Is the full force exerted on the piston transmitted to the
crank?
Ans. Only at the dead centers. At any other point of the
stroke, part of the force is transmitted as a side thrust against
the guides.
What is the nature of this turning force?
Ans. It is always less than the force acting on the piston. It
*NOTE.-The latter giving a long and easy working rod and the former a
rather short but yet a manageable one.-Thurston,
970
Steam Engines
increases from zero at the dead center to a maximum near the
center of the stroke and then diminishes to zero at the end of
the stroke.
Since the turning force is always less than the force act-
ing on the piston, is there not a considerable loss of power
caused by this peculiar action of the connecting rod?
Ans. No. Neglecting friction, the same amount of work that
is done on the piston is delivered to the crank pin by the con-
necting rod in turning the shaft.
↑ ↑ ↑ ↑
PISTON
·M-
NIC
PISTON ROD
-M-
FORWARD
S'-
NC'
+S4
CROSS
HEAD
Fig. 55.-Parallelogram of forces showing the two component forces at the
crank pin. By means of this diagram the tangential force or "turning effect"
can be obtained for any crank position.
OF
R PATH
-STROKE
RETURN
CONNECTING ROD
GUIDE
CONNECTING ROD
A:
ITANGENT
T
woj

AXIS
CRANK

CRANK PIN
B
R'
Fig. 56.-Diagram showing the effect of the angularity of the connecting rod.
The connecting rod is shown in two positions, CR and C' R', such that the
crank pin has traveled equal distances A R and B R' from the dead centers.
The piston positions are indicated by C and C', the piston having traveled on
the forward stroke the distance M and on the return stroke the distance S. For
equal crank pin travel from each end of the stroke, it is thus seen that the
piston travels further on the forward stroke than on the return stroke. Were it
not for the angularity of the rod, the piston would travel the equal distance
M' and S'. The connecting rod then increases the piston travel by a distance
NC on the forward stroke and diminishes it by a distance N' C' on the
return stroke.
Steam Engines
971
Why is there no loss of power?
Ans. Because during each stroke, the crank pin travels a
greater distance than the piston. Hence, the smaller turning
force by acting through a longer distance, does the same amount
of work as the larger force on the piston acting through the
shorter distance.
! CRANK BEARING
What is the effect of the angularity of the connecting rod?
Ans. Starting at the beginning of the forward stroke, the
inclination or angularity* of the rod with respect to the cylinder

*****
SHAFT
FLY WHEEL
B
Fig. 57.-Approved form for a long shaft carrying a heavy fly wheel. The en-
larged central portion gives stiffness to prevent springing.
D'
1
A
C
ไป
D
BEARING
•

Figs. 58 and 59.-Webbed crank arm. The crank arm is usually fastened to
the shaft with a drive, or shrink fit, and further secured by a key. The parts
shown are: A, shaft; B, webbed crank arm; C, crank pin; D, boss at shaft end;
D', boss at pin end; E, key.
972
Steam Engines
axis, causes the piston to move somewhat more than half its
stroke while the crank is moving the first quarter of its revolu-
tion, somewhat less than half stroke during the second and third
quarters, and again somewhat more than half stroke during the
fourth or last quarter of the revolution.
M
0
Ľ
D
BJJ
B
0' B'
C
L
M'

Fig. 60.-Main bearing for a vertical engine; adjustable by means of the
bolts and liners on the sides. The upper bearing surface or brass B is let into
lower brass B', B being fitted into a cap C. Both brasses are kept from turning
by dowel pins D and D'. The brasses are cut away at L and L' and the space
filled with thin strips of sheet metal or liners; these, together, with the brasses
are held firmly in place by the bolts M and M'.
What is the crank shaft?
Ans. The main shaft of an engine in which are formed the
crank or cranks for converting the reciprocating motion of the
piston or pistons into rotary motion of the shafting.
Name some types of crank shaft.
Steam Engines
973
•

R
M
S
F
03
EA
3 4
C
CAP
4
ENGINE FRAME
D
Fig. 61.—A “four piece" main bearing, as generally used on large horizontal
engines. There are two side brasses, A and B; an upper brass C, and a lower
brass D. Owing to the great weight of the wheel, little or no pressure comes
on the upper brass C. The greatest wear comes on the side brasses, which are
adjusted by means of the wedges E and F. The lower brass D, is raised for
wear by inserting liners between it and the bearing box. In some designs
wedge adjustment is provided for the lower brass. To take up wear, the side
brasses are forced nearer together by adjusting the bolts 3 and 4, which are
attached to the wedges E and F. The upper brass C, may be adjusted by filing
off sufficient metal at the lower extremities, and tightening bolts 1 and 2.
Sometimes liners are inserted between the upper and side brasses, forming an
easy mode of adjustment.
O
BF
BEARING
BOX

12
BE
G
S
D
C
A
Fig. 62.—Outboard bearing and pillow block. By means of the wedge, bolts,
and set screws as shown, the position of the bearing may be adjusted either
vertically or horizontally. All engines that are not self-contained should have
this type of outboard bearing to secure precision in alignment.
974
Steam Engines
Ans. 1, Built up; 2, integral; 3, overhung crank; 4, center
crank; 5, one or multi-throw depending upon the number of
cylinders.
What is the throw of a crank?
Ans. It is equal to the diameter of the crank pin path; that
is the stroke of the piston; ignorantly called half this distance.
What is provided on some crank shafts?
Ans. Counter-weights.

*
*
*
<
vi
se
s
and
………..
S
must that we to t→ ·
JA.
Figs. 63 and 64.-Ordinary split belt wheel. Wheels of 9 feet and less
diameter are made whole, and those from 10 ft. to 17 ft., are made in halves
fastened by turned bolts driven into reamed holes. Each half is provided with
four oval arms, a center rib, increasing in depth toward the arm, and a return
flange follows the outer edge of the wheel on both sides. All wheels above
14 ft. diameter, made in halves, have the rim joints made through the central
arms, instead of between arms.
What are the main bearings?
Ans. The bearings in which the crank shaft turns.
Describe a simple bearing.
E
Steam Engines
975
Ans. It consists of a box, cap, two brasses, liners and bolts
to hold the parts together.
There are many types of main bearing.
What is a fly wheel and why used?
Ans. A large heavy wheel attached to the shaft and which
by its momentum acts as a "reservoir" of energy and thus keeps
the reciprocating parts of a steam engine in motion at the dead
centers or "dampens" the inequalities of piston effort.
Explain more in detail.
Ans. The excess power produced by the engine in the early
part of the stoke is stored up in the fly wheel and given out by
it in the latter part where little or no power is developed on
account of the expansion of steam and pre-release.
What is momentum?
Ans. The power of overcoming resistance possessed by a body
by virtue of its motion.
Give another name for momentum.
Ans. Dynamic inertia.
What other duty is performed by some fly wheels?
Ans. With a wide face, the wheel is also used as a pulley for
pulley and belt drive.
What kind of engine requires a very heavy fly wheel and
why?
Ans. The gas engine because of its inherent defect of deliver-
ing only one impulse or power stroke in two revolutions per
cylinder.
976
Steam Engines
•
How many power strokes per revolution of a single
cylinder double acting steam engine?
Ans. Two.
*
:
*NOTE.—As far as turning effect, that is, the number of power strokes per revo-
lution is concerned, one double acting steam cylinder is equivalent to four (four
cycle) gas engine cylinders. This is one of the numerous inherent defects of gas
engines which make them inferior to steam engines in many respects.
Indicators
977
CHAPTER 49
Indicators
What is an indicator?
Ans. An instrument used to record the pressure of the steam
engine at all points of the stroke as the piston moves to and fro.
It may be applied to any pressure cylinder as for instance, internal
combustion engine, compressor, pump, etc.

How is the recording made?
Ans. On a piece of paper secured to a rotative reciprocating
drum, by a pencil attached by linkage to the indicator piston
rod.
1
Of what does an indicator consist?
Ans. It consists of a small cylinder accurately bored out and
fitted with a piston capable of working in the cylinder with little
or no friction and yet practically steam tight; the piston rod is
attached to a pair of light levers at the end of one of which is
carried a pencil designed to move on a nearly up and down line.
**
How is the motion of the piston controlled?
Ans. By a spring of known tension, several of which are fur-
nished with each instrument; each spring is marked to show at
what boiler pressure it is to be used. The elasticity of the spring
is such that each pound pressure on the piston causes the pencil
to move a certain fractional part of an inch.
-
978
Indicators
Describe the drum.
Ans. Attached to the instrument is a drum which has a diam-
eter of about two inches, and around which is placed the paper,
W
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2
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K
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Fig. 1.-Sectional diagram of an indicator. A, is the swinging bar; B, the
pencil bar; C, the indicator frame; D, cylinder containing tension spring
E, coiled spring on drum roller; F, revolving cylinder or drum; G, drum pin
H, and Z, thumb screws holding drum; I, nut to connect indicator to pipe
K, lever for screwing up I; M, connection between the spring cylinder and pipe
P, piston rod, R, joint; S, pin; T, post for guide of pencil bar, V, guide pulley
for cord from reducing lever; W, swivel sleeve for cord; X, swivel pin; Y
support for swivel pin.
the ends passing underneath a piece of slit brass, fitted so tha
the paper can be held firmly after being wound around.
This cylinder is capable of a reciprocating or semi-rotative motio
Indicators
979
on its axis of such an extent that the extreme length of diagram may
be about 5 inches.
Name two types of indicator and their application.
Ans. The inside spring and the outside spring.
C
The inside spring type is used with saturated steam and the outside
spring for super-heated steam or for indicating internal combustion.
engines.

...
Battellu
MIWUURD.
DELI
What is the object of placing the
spring on the outside?
Ans. To protect it from intensely
heated gases.
Describe the operation of an in-
dicator.
Ans. Referring to fig. 1, the steam
pressure in the cylinder D, is the
same as in the cylinder at every
point of the stroke, hence the piston
will move up and down as the pres-
sure varies, and having placed a
piece of paper or card around the
drum, if the pencil be pressed
against same, it will trace a diagram
on the card and thus "indicate"
accurately what is going on inside
of the cylinder.
:
igs. 2 to 4.-Parallel motion. It consists of a pencil lever pivoted at one end
to a radial arm and at an intermediate point to a connecting arm, the action
of the latter giving the parallel motion. Between the radial and connecting
arms is pivoted a link having its other end connected to the piston rod. The
parallel motion of the device is progressively shown in the three views.

980
Licators
What is necessary to guide the pencil?
Ans. Mechanism to impart a straight motion in a direction
parallel with the axis of the drum, as shown in figs. 2 to 4.
What do the numbers on indicator springs denote?
Ans. The pounds pressure of steam required to raise the
pencil one inch. See figs. 5 to 9.
L
50
15
95
50
NANI
GAL
'pora"
Figs. 5 to 9.—Various indicator springs showing designs used on the leading
makes of indicators.
How is the vertical movement of the pencil on the traced
diagram measured?
Ans. By scales corresponding to the numbers on the springs
each division representing one lb. of steam. See fig. 10.
How must the drum move with respect to the engin
piston?
Ans. The drum must move in step with the piston.
Indicators
981
10
How is the movement obtained?
Ans. The movement is usually derived from the cross head,
and the appliance used to reduce the movement to that adapted
to the drum is called the reducing motion.

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MINICAÉHO. A
Fig. 10.—Triangular boxwood indicator scale. The six faces give six different
scales corresponding to springs of like number.
30
OC

Fig. 11.-Indicator head showing method of changing a spring. Unscrew the
head of the indicator, hold the carrying ring as shown, and the piston and
spring may be easily disconnected from the moving parts and head.
982
Indicators
Fig. 12 shows the ordinary lever motion; fig. 13 the pantograph
and fig. 14 a self-contained reducing motion.
How should the indicator be connected and why?
Ans. The connection between the indicator and the engine
cylinder must be as direct as possible, so that the pressure
acting upon the indicator piston at any instant will be as

20. CIN.0.
E
B
D
Fig. 12.—Lever reducing motion. CD, is the lever which is pivoted at one end
to a fixed point C, and at the other D, to a link DE, which is pivoted at E,
to the cross head. The cord for the indicator drum is attached to the lever CD,
at some point A, so selected as to give the proper length of movement to the
drum. A spring attached to the drum keeps the card taut at all times. The
length of the link DE, should be such that CD, will be vertical when the cross
head is at half stroke. In all lever motions there is a radical defect due to the
fact that while the cross head moves in a straight line, any point on the lever
swings through an arc of a circle.
nearly as possible the same as the pressure acting upon the
engine piston at the same instant.
How do you take an indicator diagram?
Ans. When the instrument is properly connected to the
engine, open the cock and let in the steam, which will set in
Indicators
983
motion the piston and levers. Press one finger lightly on top of
the piston rod of the instrument to see if it be working smoothly.
If a rough action be felt, indicating the presence of grit or some
derangement, shut the steam cock and correct the fault. The paper is
put on the drum by wrapping it snugly around the drum at the top,
bending it around and allowing the ends to project between the clips
at the top, then by taking the lower corners which protrude between

1. 12
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48418 BECAME »
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Fig. 13.-Pantograph reducing motion. This device is easily made. The mem-
bers usually consist of strips of hardwood 1% X6X16 ins. The pantograph
is pivoted at the point B, by a stud or winged thumb nut to a part of any
character secured to the engine room floor, and the nut A, is adjusted to a
suitable piece secured to the cross head of the engine. The driving cord for
the indicator is attached to a pin whose position may be changed by placing
the pins C and D, in the holes provided for them. In doing this, the attach-
ment pin must always be on the straight line between the points A and B.
the thumb and the second finger, the paper is drawn down tightly
over the drum. Now open steam cock and warm instrument.
What precautions should be taken on non-condensing
engines?
984
Indicators
Ans. On these engines it is well to turn the cock so that the
steam will blow into
the atmosphere until
it shows blue and

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B
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MENU FROSTMARKANTADA Sambo
Fig. 14.-Self contained reducing motion. It consists of a base K, provided
with a worm shaft R, on which the flanged pulley O, is rotated, the outer
bearing being a pivot p, which receives the thrust of shaft R. It is connected
to the indicator upon the arm that supports the drum B, and teeth on spool g.
d is a spring case, and u, a thumb piece. On R, is secured a collar (not shown)
through which a clutch pin, secured direct to the thumb piece, slides. The
flanged pulley O, runs freely on the worm shaft R, and has on its outside a
clutch shaped hub. To this pulley O, is connected the actuating cord, which
should encircle it a sufficient number of times to have its length when unwound
a little more than equal the length of the stroke of the engine. The other end
of the cord is secured either to the cross head of the engine, to a standard
bolted to the same, or to any moving part that has a similar motion, and
must be connected in line from pulley O. Enclosed in the spring case d, is a
small, plain spiral steel spring which operates to return the pulley O, back to
its starting point, after it has been revolved in one direction by the forward
movement of the engine cross head. As this pulley O, has an independent,
rotating back and forth motion on the worm shaft R, the necessity of unhooking
the cord when the indicator is not being operated is entirely overcome. The
paper drum B, is rotated forward by the pulley O, through R, engaging with
the worm gear g, and in the opposite direction by the spring.

Indicators
985
1
13
73
g. 15.-Indicator piped to cylinder with two way cock. By turning the cock
to right or left the indicator is put in communication with either end of the
cylinder, thus enabling diagrams to be taken from both head and crank ends.
without disconnecting the indicator..
gs. 16 and 17.-Two types of cock used in indicator piping. Fig. 16, two
way cock; fig. 17, long turn angle cock. The two way cock is piped as
shown
in fig. 15. However, since the piping is usually permanent, this method mate-
rially increases the clearance of the engine which is objectionable, and is
reduced by substituting for the two way cock an easy turn T and, using two
angle cocks in place of the elbows.
986
Indicators
dry. When the water has disappeared and the pencil is vibrating
smoothly, the paper drum being in motion, hold the penci
lightly against the paper and allow it to trace the diagram

BACK
UPRIGHT
CYLINDER
CAP
PISTON
ROD
SLEEVE
HOLLOW
PISTON ROD
BALL
SWIVEL
CHECK
-NUT
PENCIL
ARM
DETENT
DOG
-SPRING
STEEL
STANDARD
BRONZE CYLINDER
LIVE STEAM JACKET
PISTON
UNION PLUO
-UNION
-PAPER
CLIP

-PAPER
DRUM
DRUM
BARREL
REDUCING
WHEEL
BODY
Fig. 18.-Cross section of outside spring indicator with names of parts.
How long should the pencil be held on the diagram?
Ans. For ordinary purposes of exhibition, showing the val
action, distribution, etc., one revolution is sufficient to hold t
pencil in contact with the paper. To show the governor acti
variation of load, etc., the pencil will have to be held on for
number of revolutions; and when measuring power, the pen

Indicators
987
should be allowed to pass from ten to twenty times over, and
the average diagram measured. Turn the cock off and bring
the pencil again to the paper tracing the atmospheric line. It
s not good practice to trace the atmospheric line first, as the
ndicator and spring are not then heated, and under the same
onditions as when the diagram is taken.
What is the procedure in taking more than one card?
Ans. It is necessary to stop the drum while removing the
ard from the clips; this is done in some cases by making the
0.917
MA
g. 19.-Removing piston for cleaning of outside spring indicator shown in
fig. 18.
STANDARD SPRINGS
SCALE OF SPRING, LB/SQ IN. PER INCH CARD HEIGHT
10 16 20 30 40 60 80 | 100 | 125 | 180
MAXIMUM PRESSURE, LB/SQ IN.
16 28 35 60 80 120 160 200 250 360
The above spring ratings are for the standard piston of ½
square inch area. For indicating an engine with steam pres-
sure higher than 360 lb/sq inch a smaller size piston must be
used and can be installed in the indicator at the factory...gi

988
Indicators
cord in two lengths, and unhooking, whenever the drum is t
be stopped.
JO
Fig. 20.-Replacing spring of outside spring indicator shown in fig. 18.
II
Fig. 21. Removing sleeve of outside spring indicator shown in fig. 18.
The Slide Valve
989
CHAPTER 50
S
The Slide Valve
An important part of a steam engineer's examination is the
lide valve and valve gear. He should have a thorough knowl-
dge of these subjects.
What is a slide valve?
Ans. A long rectangular box-like casting designed to secure
ne proper distribution of steam to and from the cylinder.
What other name is given to the slide valve and why?
Ans. It is sometimes called the "simple D valve" on account
f its resemblance to the capital letter D turned with the flat
de facing its seat, as shown in fig. 1.
What do they mean by "distribution" of steam?
Ans. Under the action of the valve: 1, The admission; 2,
ut off; 3, pre-release; 4, exhaust; 5, compression; and 6, pre-
dmission of the steam necessary for the proper working of
he engine.
What is the valve seat?
Ans. A flat smooth surface upon which the valve moves to
nd fro, and which is pierced by the steam and exhaust ports,
s shown in fig. 3.
990
The Slide Vavle

STEAM PIPE
CONNECTION.
OVER TRAVEL
COVER
HEAD.
PISTON
SNAP RINGS
HEAD
END
FLANGE
FRIEND
STEAM
DRAIN
STEAM CHEST GOVER
SEAT
LIMIT
ཅུ་་ ་་
PORT
PASSAGE
SLIDE VALVE
EXHAUST
CAVITY
FORT
EXHAUST
PASSAGE
CYLINDER
WY
PORT
YOKE
STEAM PASSAGE
ROD:
WAASMU
SCREW STUFFING BOX
VALVE STEM
GLAND
CAP
·
BUSHING
FLANGE STUFFING BOX
BORE
JOOOOOWNDAY
GLAND
COUNTER-BORE
FLANGE
CRANK
END
INSULATION
DRAIN
vlinder showing the various parts with their names.
The Slide Valve
991
VALVE CITEST DCAT LIMITS
HEAD COVER FLANGE
BRIDGES
ITHA
||||||
m
O
L
O
STEAM PORTS
EXHAUST PORT
CASING
CASING BAND
VALVE STEM
STUFFING BOX
PISTON ROD
STUFFING BOX
GLAND
VALVE STEM
PISTON ROD
valve seat, ports, etc.
Fig. 2.—View of steam chest of the cylinder illustrated in fig. 1, with cover and valve removed, showing the


992
The Slide Valve
What is the difference between a port and a passage?
Ans. A port is the entrance at the valve seat to: 1, Eithe
a steam passage leading to the cylinder; or 2, the exhaus
passage leading to the exhaust pipe.
Don't be guilty of calling a port a passage or a passage a port — thi
is either ignorantly or carelessly done but in either case inexcusable.
What is the steam edge of a valve?
Ans. The edge which opens or closes the port admitting an
cutting off steam to the cylinder respectively. Fig. 4.
STEAM EDGE,
A
EXHAUST EDGE
GUIDE SURFACE
JK4
SEAT LIMIT
B
1.... 14 ********
BRIDGE
BAMBA
SEX:
STEAM EDGE
BRIDGE
A1/1/18EISESTELIJZE.
HERE
SEAT LIMIT`
Fig. 3.-Sectional view of steam chest and valve seat. The steam and exhau
passages terminate with fillets as M, S, so that the ports may be proper
machined. B, C, and F, G, are the steam ports; C, D, and E, F, the bridge
and D, E, the exhaust port. The seat extends from A to H,
What is the exhaust edge of a valve?
Ans. The edge which opens or closes the port for release
compression. Fig. 4.
Why is the length of a valve seat less than the valve plu
its travel?

The Slide Valve
993
Ans. To obtain over travel and thus avoid wearing shoulders
on the seat. Figs. 5 and 6.
Why is the length of the port made much greater than
the width?
Ans. So that the ports may be opened and closed very
quickly to reduce wire drawing.
STEAM EDGES OF VALVE
EXHAUST EDGES OF VALVE
EXHAUST
CAVITY
EXHAUST EDGES OF STEAM PORTS
STEAM EDGES OF STEAM PORTS
Fig. 4.-Sectional view of valve on seat illustrating the term steam edge, exhaust
edge of both valve and seat.
What is wire drawing?
Ans. The effect produced by steam flowing through a con-
stricted passage which results in a fall of pressure with its
attendant loss in engine efficiency.
What governs the length of the ports?
Ans. The diameter of the cylinder.
What governs the width of the ports?
Ans. It should be such (depending upon the length) as to
994
The Slide Valve
LL.
G
W
LENGTH OF SEAT
H C H
PORTION BALANCED
AT END OF TRAVEL
ווי
SHORTENED SEAT
PORTION BALANCED
AT END OF TRAVEL
S
Figs. 5 and 6.-Section of seat and valve at end of travel showing effect of reducing length of seat. In fig. 5
the seat is of such length that the over travel of the valve is very small. When the valve is in the extreme
position only the small portion M, will be balanced by steam acting on both sides as indicated by the arrows.
If the seat length be reduced to a minimum so that when the valve is in the extreme position only enough
contact area is left to produce a tight joint. The considerable portion S, which has over traveled will be
balanced by the steam acting on both sides as indicated by the arrows, thus materially reducing the load
on the valve, causing it to consume less power in operation and to wear less rapidly.
give the amount of port area required for the proper flow of the steam.
Why is the exhaust port made wider than the steam ports?
Ans. Because the valve, on account of the extent of its movement, partly covers
this port during exhaust and the minimum opening for exhaust must be more than
for admission of steam. Figs. 5 and 6.
Why?
Ans. To reduce the velocity of flow during exhaust for the purpose of reducing the
་==

The Slide Valve
995
What names are given to the "edges" of a slide valve
and why?
STEAM EDGE
Ans. The edge at either end is called the steam edge because
this edge controls the admission and cut off of steam to the
cylinder; the inner edge is called the exhaust edge because it
controls the release to exhaust and compression of the exhaust
steam. Fig. 7.

EXHAUST
ARCH
EXHAUST EDGE-
STEAM EDGE
FACE
FACE
Fig. 7.-Sectional view of slide valve showing the principal parts. It is important
to remember the names given in the figure.
What important defect is there in the operation of the
ordinary (that is not balanced) slide valve?
Ans. The excessive pressure caused by the steam pressing
the valve against its seat, causes considerable friction and
wear, moreover rendering the valve unsuited to the use of
superheated steam.
996
The Slide Valve
What provision is sometimes made for relieving the
pressure on the slide valve?
Ans. Various devices have been used to exclude steam from
the top of the valve, so that the pressure cannot be exerted in a
direction which would press the valve against its seat.
What is such a valve called?
Ans. A balanced slide valve. Fig. 8.

PACKING RINGS
OB
THREADED CLAMP-
STEAM CHEST CAP
BALANCE RING
·STEM ENLARGED
TO FORM
SHOULDER
Fig. 8.-Sectional view of a balanced slide valve. It is held against the seat by
steam pressure on a small area of the back of the valve and by this means is
made nearly steam tight. Also, the valve by this means is made to automatically
follow up its wear, so that the steam consumption will be lower after the engine
has been in use for a time, rather than higher.
What other type of valve is inherently balanced, that is,
without any balance devices?
Ans. The piston valve.
This valve is the type especially adapted to superheated steam.
The Slide Valve
997
Lap
What is the central position of a valve called?
Ans. The neutral position. Fig. 9.
This is an important position because lap measurements are based
upon this position.
STEAM
LAP
What is lap?
Ans. That portion of the valve face which overlaps the ports
when the valve is in its central or neutral position. Fig. 9.
M
L

CD
EXHAUST
LAP
Fig. 9.-The plain D, slide valve showing "lap." A B is the outside or steam
lap; CD, the inside or exhaust lap. The figure also illustrates the neutral
position of the valve.
What is usually understood by the term lap?
Ans. The outside or steam lap.
What is the outside or steam lap?
Ans. That portion of the valve face which overlaps the
steam edges of the steam ports when the valve is in its central
or neutral position.
998
The Slide Valve
What is inside or exhaust lap?
Ans. That portion of the valve face which overlaps the
exhaust edges of the steam ports when the valve is in its
central or neutral position. Fig. 10.
What is the effect of outside or steam lap?
Ans. It causes the valve to cut off the supply of live steam
to the cylinder before the end of the stroke, the greater the
amount of lap the earlier the cut off.
M
NEUTRAL POSITION OF VALVE

B
POSITIVE INSIDE LAP
Fig. 10.-Illustrating negative and positive inside lap. A valve is some-
times given negative inside lap at one end to equalize release and compression;
the irregularity being due to the angularity of the connecting rod.
NEGATIVE INSIDE LAP
What is the effect of inside lap?
Ans. It: 1, Causes the valve to open later for exhaust, that
is, pre-release takes place later; and 2, causes the exhaust to
close sooner, thus shutting in a larger portion of the exhaust
steam, that is, causes compression to occur earlier.
The Slide Valve
999
•
What is negative inside lap?
Ans. The space left between the exhaust edge of the seat and
he exhaust edge of the valve when it is in its neutral position.
A B in fig. 10.
LINE AND LINE
What is the object of inside negative lap?
Ans. To equalize certain irregularities of exhaust due to the
angularity* of the connecting rod.
Σ

LAP +
PORT OPENING
Fig. 11.—Illustrating "line and line" position.
What is the effect of negative inside lap?
Ans. It: 1, Causes the valve to open sooner, that is, pre-release
takes place earlier; and 2, causes the valve to close later; that is,
compression takes place later.
What is line and line position?
Ans. When one edge of the valve is in the same line or plane
with the corresponding edge of the port. Fig. 11.
*NOTE.-The term angularity and its effect on the action of the valve gear is
later fully explained.
1000
The Slide Valve
What occurs when the steam edge of the valve is in lin
and line position?
Ans. Admission or cut off occurs depending upon the direc
tion in which the valve is moving.
What occurs when the exhaust edge of the valve is in
line and line position?
Ans. Pre-release or compression occurs, depending upon th
direction in which the valve is moving.
LEAD
-A'
Σ
LAP + LEAD
M

Fig. 12.-Valve in tead position. This is the position of the valve when the
piston is at the beginning of the stroke.
Lead
What is lead?
Ans. The amount by which the steam port is open for the
admission of steam when the piston is at the beginning of the
stroke or "dead center." Fig. 12.
What is the dead center?
The Slide Valve
1001
Ans. The point of the stroke at which the connecting rod of a
steam engine has no power to turn the crank.
NEGATIVE
LEAD
When does it occur?
Ans. When the position of the cylinder axis and axis of the
connecting rod lie in the same plane. It occurs at the beginning
and end of the stroke.
What is the object of lead?

LAP +
NEGATIVE
LEAD
Fig. 13.-Valve in negative lead position. Negative lead is sometimes given
with link motion full gear to prevent excessive lead when cutting off short, as
on locomotives.
Ans. To admit live steam to the cylinder before the beginning
of the stroke so that the pressure of the compressed exhaust
steam in the clearance space will be increased to live steam pres-
sure at the beginning of the stroke.
Why is this desirable?
Ans. 'It helps absorb the inertia of the moving parts and pro-
vides maximum steam pressure on the piston at the beginning
of the stroke.
What is negative lead?
1002
The Slide Valve
Ans. The amount by which the steam port is closed to admis-
sion when the piston is at the beginning of the stroke. Fig. 13.
What is the object of negative lead?
Ans. On some types of valve gear, as the link motion, the
lead increases with the degree of expansion. Hence, in full gear,

M
→

S
Figs. 14 and 15.-Valve in lead position illustrating variable lead; thus
Tead M, with gear in late cut off position is less than lead S, for early cut off
A peculiarity of the link motion gear is this variable lead. With the link
motion in shortening the cut off by "hooking up"; open rods give increasing
lead, while crossed rods give decreasing lead.
that is, for the maximum cut off, a negative lead is given to
prevent excessive lead when cutting off very early.
What do you mean by lead unqualified?
Ans. Positive lead or the amount by which the steam port is
open for the admission of steam at the beginning of the stroke.
The Slide Valve
1003
What is inside or exhaust lead?
Ans. The amount by which the steam port is opened to ex-
haust when the piston is at the beginning of the stroke.
What is constant lead?
Ans. Lead which does not change for different degrees of
expansion.


Figs. 16 and 17.-Valve in lead positions illustrating equal lead, that is,
Tead M, at one end of the cylinder is the same as lead S, at the other end.
What is variable lead?
Ans. Lead which changes with the degree of expansion, as
M and S in figs. 14 and 15.
What is equal lead?
Ans. Lead which is the same at each end of the cylinder, as
M and S in figs. 16 and 17.
1004
The Slide Valve
Pre-Admission
What is pre-admission?
Ans. The opening of the steam port for the admission of
steam to the cylinder before the beginning of the stroke.
PORT OPENING
LESS THAN PORT
Upon what does pre-admission depend?
Ans. On the amount of lead.
Σ

A
LAP + PORT
OPENING
Fig. 18.—Valve fully opened for admission; this comes when the piston is about
half way between the beginning of the stroke and cut off position. Usually
the port is only partially opened, as here shown, because the speed of the
steam through the port during admission should be greater than during exhaust.
What is the object of pre-admission?
Ans. Principally to secure maximum steam pressure at the
beginning of the stroke and in some cases (high speed engines)
to assist compression in resisting the momentum of the moving
parts and bringing them to a state of rest at the dead center.
What is the objection to pre-admission?
Ans. It increases initial condensation.
The Slide Valve
1005

ADMISSION
M
LAP
CUT OFF
Figs. 19 and 20.-Positions of the valve at the beginning of admission and at cut off. It will be noted that
the position of the valve is the same in each case but the direction of motion is not the same.
What is initial condensation?
Ans. Condensation which takes place during pre-admission.
M
Admission
What is admission?
Ans. The flow of live steam into the cylinder from the beginning of the stroke to the
point of cut off. As in figs. 19 and 20.
What do you mean by live steam?

1006
The Slide Valve
;
Ans. Steam taken directly from the boiler and which has not
been admitted nor expanded in the cylinder.
How long is the period of admission?
Ans. Very variable, depending upon the type of engine and
valve gear.

1
CLEARANCE
APPARENT CUT OFF
C
REAL CUT OFF-
-1+C·
1
L-
STROKE

SCALE
3
2 3 4 5 6 7 8 9 9 10
Fig. 21.-The apparent and real cut off. The effect of cylinder clearance is
to make the number of expansions less than would correspond to the apparent
cut off, that is, the cut off of the valve gear. Thus, if the valve gear cut off at
one-half stroke, there would be without clearance, two expansions. With, say
10 per cent clearance, the expansions would be reduced to 1÷(.1 +.5)=1.66.
The real cut off would then be 1÷1.66.6 stroke. In the figure the clearance
volume 7 includes besides the volume between the piston at end of stroke and
cylinder head, the volume of the steam passage (not shown) up to the steam port.
What is inside admission?
Ans. A valve which has its exhaust edges at each end and its
steam edges between as on some piston valves,
The Slide Valve
1007
What is the advantage of inside admission?
Ans. The valve stem stuffing box is not exposed to the high
pressure steam but only to the exhaust, hence it is easier on
packing and requires less attention in keeping the joint tight.
Where would this be objectionable?
Ans. For condensing operations there is no indication whether
there be an air leak through the stuffing box into the condenser.
What other objection is there to inside admission?
Ans. Valve harder to set as the steam edge of the valve and
steam edge of the port are not visible-in other words you can't
see what you are doing, but must rely on measurements.
Cut Off
What is cut off?
Ans. The closure of the steam port to the admission of steam.
Fig. 21.
How is it usually expressed?
Ans. As a fraction of the stroke as 1/2, 6/10, 3/4, etc.
What is cut off thus expressed called?
Ans. The apparent cut off. Fig. 19.
Why?
Ans. Because it does not represent the actual point at which
cut off takes place considering clearance.
What is the real cut off?
Ans. The sum of the apparent cut off plus the percentage of
clearance. Fig. 21.
1008
The Slide Valve
How is clearance classified?
Ans. As linear and volumetric.
What is linear clearance and how expressed?
Ans. The linear distance between the piston and the cylinder
head when the piston is at the beginning of the stroke; expresse d
in percentage of the stroke.
PRE-RELEASE
INSIDE
LAP
Σ

Fig. 22.-Position of the valve at beginning of pre-release. This occurs just
before the piston reaches the end of the stroke so as to rid the cylinder of most
of the steam before the beginning of the return stroke, and thus reduce the
back pressure of exhaust as much as possible.
Pre-Release
What is pre-release?
Ans. The opening of the steam port to exhaust before the
piston has completed its stroke. Fig. 22.
What is the period of pre-release?
The Slide Valve
1009
PORT
OPENING
M
-R
EXHAUST
OPENING
On what does pre-release depend?
Ans. Upon the amount of exhaust lap.
M'
What is the end of the stroke position called?
Ans. The terminal position.
RELEASE
OPENING
Fig. 23.—Valve in full release position, that is, in the position of maximum opening to exhaust, this occurs
when the piston is nearly half way between the beginning of the return stroke and the compression position.
7

Ans. The interval from the opening of the valve to exhaust till the piston has
reached the end of the stroke.
1010
The Slide Valve
What governs the amount of pre-release in design?
Ans. The piston speed and the quantity of steam to be dis-
charged.
What happens during pre-release?
Ans. The greater part of the expanded steam is exhausted,
the pressure rapidly drops especially because of the slow move-
ment of the piston near the end of the stroke.
M'|| M

INSIDE
LAP
COMPRESSION
Fig. 24.-Position of the valve at the beginning of compression. This occurs
Usually when the piston has traveled about three-quarters of the return stroke,
more or less dependent upon the type of engine and working conditions. The
object of compression is to introduce a spring like back pressure to absorb or
'cushion" the momentum of the reciprocating parts and bring them to a state
of rest at the end of the stroke; also to increase the efficiency by saving some
of the exhaust steam. Note that the valve is in the same position as at pre-
release (fig. 22) but is moving in the opposite direction.
Release
What is release?
Ans. The exhaust of steam from the beginning of the return
stroke (terminal position) to the beginning of compression.
Fig. 23.
*
The Slide Valve
1011
What happens during release?
Ans. The remaining steam in the cylinder up to the point of
compression is exhausted to atmosphere or condenser, depend-
ing upon whether the engine be operating non-condensing
(“high pressure”) or condensing.
Why is an engine operating non-condensing called "high
pressure?"
Ans. Because it exhausts at a comparatively high absolute
pressure compared to condensing operation.
Thus exhausting to atmosphere takes place at about 16 lbs. absolute
pressure and to condenser at about 2 lbs. absolute pressure.
Compression
What is compression?
Ans. The closing of the steam port to exhaust before the
piston has reached the end of its stroke. Fig. 24.
What happens?
Ans. It shuts in a portion of the exhaust steam and by the
return stroke movement of the piston, compresses the steam
up to the point of pre-admission, that is, until pre-admission
begins.
What is the effect of compression?
Ans. The rapidly increasing back pressure due to compression
acts as a spring to cushion the momentum (that is, dynamic
inertia) of the moving parts, and brings them to a state of rest
at the end of the stroke.
1012
The Slide Valve
What is the effect of compression called?
Ans. Cushioning.
On what does compression depend?
Ans. On the exhaust lap and angular advance.*
M
A
LAR
"
G
A
PORT OPENING
TRAVEL
บบบบบบ
Μ'

7
F' G'
Fig. 25.—Illustrating port opening and half travel of the valve. The valve is
shown in dotted section in its neutral position, and in full section in its extreme
position. Half travel is equal to the lap plus the port opening;
the latter being the distance the steam edge of the valve moves past the steam
edge of the port during admission. This represents the movement of the valve
on either side of its central or neutral position and lap+port opening =
A F+F A'. As drawn, the port opening is greater than the port by the
amount G A'.
What is the effect?
Ans. The greater the exhaust lap (or angular advance) the
sooner compression begins.
*NOTE.—All about angular advance is presented in the next Chapter on
Valve Gears.
The Slide Valve
1013
HALF TRAVEL (MAXIMUM ECCENTRICITY)

PORT OPENING
PORT OPENING
PORT
HALF TRAVEL (MINIMUM ECCENTRICITY)

Y
PORT
Figs. 26 and 27.-Valve in extreme position showing: 1, port opening greater
than the port, and 2, port opening less than the port. With plain gear in
which the expansion is not variable, the valve is designed for a port opening
less than the port, because for admission less port area is required than for
exhaust, the steam being admitted in good practice, at a velocity of 8,000 ft.
per minute and exhausted at 6,000 ft. per minute. With variable expansion
gears, which vary the expansion, as later explained by the method of com-
bined variable throw and variable angular advance, the travel of the
valve is considerably reduced for early cut off, hence, the port opening is
made more than sufficient at late cut off as in fig. 26, in order that the reduced
opening for early cut off as in fig. 27 will not be too small.
1014
The Slide Valve
E
M
SEAT LIMIT
OVER TRAVEL
♡
TRAVEL OF VALVE
1/2 TRAVEL
✓
"DANTI
... /
положени
WEETENER
M
EXHAUST OPENING
1/2 TRAVEL
EXTREME
POSITION
Μ
lOPE
PORT OPENING
LAP + PORT OPENING
YESTERD
THERE ARE THE
777
1177/0
2
CATE
THERE IS AN
THREE THE
antig
THERE
Affent
The
"/
14
"
E'
-
B
NEUTRAL
POSITION
A
Fig. 28.-Showing valve in the two extreme positions M', and M", to illustrate the travel. M, half way
between corresponds to the neutral position. The valve as shown moves to either side of M, a distance equal
to the lap plus the port opening; the travel or entire movement, therefore, is equal to twice the lap
plus twice the port opening.
Should compression begin at the same point in a condensing engine as in
• a non-condensing engine?
Ans. No.

The Slide Valve
1015
Why?
Ans. The beginning of compression being at lower pressure
in a condensing engine than in a so-called high pressure engine,
compression must begin earlier condensing to obtain equal
cushioning.
E
Does compression result in a loss? Why?
Ans. No, because the power required to compress the confined
steam is given out by its expansion on the next stroke.
A B
F
SUPPLEMENTARY STEAM PASSAGE

G
+
D
H
H'
D'
G'
F'
B' A'
E'
Mi
Fig. 29.-The Allen valve. The supplementary passage is for double admission
which is desirable on locomotives fitted with link motion as they are usually
run with short cut offs, and the action of the link under these conditions gives
very little port opening.
Is there any saving by compression? Why?
Ans. Yes, because the compressed steam is utilized to help
fill the clearance space instead of admitting live steam for this
purpose.
1016
The Slide Valve

Fig. 30.-The Allen valve in lead position showing double admission. It should
be noted that the second admission through the supplementary port, depends
on the length of the seat which forms the lap.
Y
Y
ދ
THE INTER
LEAD
M
LINEAR ADVANCE
M'

///
4/1/21
//A
LAP
Fig. 31.-Showing valve in its position of linear advance. When the piston
is at the beginning of the stroke, the valve must be at a distance from its
neutral position equal to the lap plus the lead. The valve is shown in solid
black in its linear advance position, and in dotted section in its neutral position.
The Slide Valve
1017

E
A
B
G
H
D
C
E
A
G
B
H
D
E
F
A B
G
C
Figs. 32 and 33.-The maximum admission of the Allen valve is equal to the width of the port F G (fig. 32)
less the width of the valve bridge A B, because as the valve moves to its extreme position (fig. 33) the
supplementary port B G, is closed by the valve seat.
Fig. 34.-The Allen valve with modified steam ports. The steam ports are so modified that the supplementary
port is not closed when the valve is in the extreme position. The amount of enlargement of the steam port
for proper admission will depend on the width of the valve bridge A B.
Port Opening
What is port opening?
Ans. The extent to which the steam port is opened when the valve is at the end of
the stroke, that is, the distance the steam edge of the valve moves past the steam
edge of the port during admission. Fig. 25.


1018
The Slide Valve
Table Showing Effect of Changes in Lap, Throw, Angular Advance, Etc.
Increasing angular advance, decreasing throw
Swinging eccentric
Pin opposite
crank
Event
icsd..
port opening.
cut off..
pre-release
exhaust opening
compression
Increasing Increasing Increasing
Period outside inside `angular
lap
lap
advance
reduced
pre-admission reduced
reduced
earlier
reduced
increased
admission
expansion
exhaust
unchanged
unchanged
unchanged
unchanged
3/4 STROKE-
STROKE
111111
unchanged
increased
unchanged increased
unchanged
earlier
unchanged
unchanged
unchanged
increased
later
reduced
reduced
earlier
B
Increasing
throw
increased
increased
increased
later
unchanged increased
unchanged reduced
earlier unchanged
unchanged unchanged
unchanged increased
earlier
unchanged
Shifting
eccentric
constant
unchanged
reduced
earlier
reduced
increased
earlier
unchanged
reduced
earlier
Pin on
crank
increased
Increased
reduced
earlier
reduced
increased
earlier
unchanged
E
reduced
earlier
3/4 CUT OFF
0
decreased
decreased
decreased
POSITION OF CRANK PIN FOR
earlier
reduced
increased
earlier
unchanged
reduced
earlier
G
Offset pin
on crank
small increase
small increase
decreased
earlier
reduced
increased
earlier
unchanged
reduced
earlier
Fig. 35.-Diagram for finding the crank position corresponding to a given piston position. Since the piston
and cross head move in unison, the latter is used. With the wrist pin as center, and connecting rod as radius,
an arc D C, is described cutting the crank pin circle in C. A line connecting the center of the circle with C,
...




The Slide Valve
1019
K
What is the extent of this movement and why?
Ans. Normally less than the width of the port because less
opening suffices for admission than for exhaust because during
exhaust the entire port should be opened for proper flow of ex-
haust steam. Fig. 27.
CENTRIC
CIRCLE
OPENING
PORT
CIRCLE
0
√c}
1/2
M
A
LAP
CIRCLE
E-
C.
CUT OFF
•
PORT
OPENING
-TRAVEL OF VALVE-
G
HN
S
F
C
COMPRESSION
C'
RELEASE
EF= OUTSIDE LAP
EG= = INSIDE LAP
LINEAR ADVANCE
16 LEAD
ANGULAR ADVANCE
ig. 36.-The Bilgram diagram for finding the lap, angular advance travel,
etc., of the slide valve. With this diagram, any valve problem may be easily
and quickly solved.
What is the extent of port opening abnormally and why?
Ans. On variable cut off engines at late cut off the opening
made greater than the width of the port to secure adequate
ort opening at early cut off, a characteristic of shifting eccen-
ric variable cut off gears (later explained) is that port opening
ecreases as the cut off is shortened. Fig. 26.
at

1020
The Slide Valve
What difficulty is encountered with early cut off by the
method just mentioned?
Ans. The exhaust port opening is reduced thus "choking" the
exhaust.

K'
What is the travel of a valve?
Ans. The extent of its to and fro movement. Fig. 28.
34 CUT OFF
K
Hof
Travel

B'
B
IG
O A. A
A.A N
}
TRAVEL FOR 2 IN.
PORT OPENING
E'
G'
N'.
~ TRAVEL FOR 3/4 IN. PORT OPENING
Fig. 37.-DEFECTS OF THE SLIDE VALVE I. A small increase in the
port opening requires a large increase in the travel, and additiona
lap. In the diagram increasing the port opening OA, to OA', ¼ inch
increases the travel K N, to K' N', or 18 inches.
What is the extent of the travel of the valve?
Ans. Travel of valve = twice the lap + twice the port opening
What is over travel?
The Slide Valve
1021
Ans. The extent to which the steam edge of the valve moves
beyond the seat limit, as AE, fig. 28.
What is the object of over travel?
Ans. 1, to prevent wearing shoulders on the seat; and 2, to
reduce the unbalanced load on the valve.
/
CUT OFF
TRAVEL FOR 3/4 CUT OFF
TRAVEL FOR 1/2 CUT OFF
CUT OFF

LAP FOR
2 CUT OFF
\LAP FOR
3/4 CUT OFF
Fig. 38.-DEFECTS OF SLIDE VALVE: The travel is excessive when the
valve is designed for an early cut off; considerable lap is required.
The diagram shows the large increase in travel necessary in shortening the
cut off from 34 to ½ stroke, and also why the slide valve is not suitable for
cut offs shorter than 2 stroke.
1022
The Slide Valve
6
Linear Advance
What is linear advance?
Ans. The distance the valve has moved from its neutral posi-
tion when the piston is at the beginning of the stroke.
B'
B
J-24
½ CUT OFF

LAP
ORDINARY VALVE
LAP
ALLEN VALVE
Л
116
LEAD
7
A A'
TRAVEL ALLEN VALVE
TRAVEL ORDINARY VALVE
Fig. 39.—Comparative diagrams showing travel of Allen and plain slide valve.
The Allen valve requires only half the travel and half the lead of the plain
slide valve.
32
LEAD
Upon what does linear advance depend?
พ
Ans. On the amount of lap and lead, that is linear advance =
lap* + lead.
*NOTE.—It should be remembered that the word lap unqualified always
means outside or steam lap.
The Slide Valve
1023
Defects of the Slide Valve.
1. A small increase in port opening requires a great increase
în lap and travel. Fig. 37.
Κ
2. The travel is excessive when the valve is designed for an early
cut off; considerable lap is required. Fig. 38.
B'

.K
1/2
42
El
C
COMPRESSION
(½ CUT OFF)
RELEASE
E' A' (2 CUT OFF)
B
A
COMPRESSION
(4 CUT OFF)
RELEASE
(3/4 CUT OFF)
BOTH
TOO
SOON
0
N
N'
Fig. 40.-DEFECTS OF THE SLIDE VALVE: For a short cut off release
and compression occur too early. The diagram shows the effect on release
and compression, of changing the cut off from 4 to 2. Either may be cor-
rected with positive or negative inside lap but the error of the other will be
correspondingly magnified.
What do you mean in this instance by an early cut off?
Ans. A cut off less than 6/10 stroke, that is the apparent cut
off.
3. On account of the large proportions and excessive travel
necessary, the slide valve is considered undesirable for cut offs
1024
The Slide Valve
shorter than one halfstroke (the limit) except for instance operated
by expansion valve gears. Fig. 39.
4. For a short (early) cut off, release and compression occur too
early. Fig. 40.
14 CUT OFF
5. For variable expansion, the port opening is inadequate, and
release and compression occur too early at short cut off. Fig. 41:
TRAVEL CIRCLE
MAXIMUM
TRAVEL
MINIMUM
TRAVEL
C'
M
O
A
A
A"B"
=

{CUT
(CUT OFF FOR NORMAL
PORT OPENING
34 CUT OFF
B
R"
R'
S
LAP
၁
PREMATURE RELEASE
AND COMPRESSION
CIRCLE
LEAD
B'
(EXCESS PORT OPENING
AT LATE CUT OFF
NORMAL PORT OPENING
(IN
JINADEQUATE PORT OPENING
AT EARLY CUT OFF
Fig. 41.—DEFECTS OF THE SLIDE VALVE. —For variable expansion the
port opening is inadequate, and release and compression occur too early
at short cut off. The diagram shows the effects of changing the cut off from 3/4
to 4 by the method of combined variable angular advance and
variable travel. Evidently, when variable expansion is thus obtained, the
travel of the valve should be as great as possible in "full gear," because of
the decreasing port opening with shortening of the cut off. From the diagram,
it is also clear that the shorter the full gear cut off, the larger the port opening
at earliest cut off.
The Valve Gear
1025
CHAPTER 51
The Valve Gear
What is the valve gear?
Ans. The combination of parts by which a reciprocating, or
to and fro motion, is imparted to the valve from the rotary mo-
tion of the shaft in proper angular relation to the crank.
Of what does the simplest form of valve gear as provided
for a slide valve consist?
Ans. 1, Yoke; 2, spindle; 3, valve; 4, guide; 5, eccentric rod;
6, eccentric strap; and 7, eccentric. Figs. 1 and 2.
How is motion imparted to the valve?
Ans. By a yoke and spindle which connects with the rest of
the valve gear.
Of what does the yoke consist?
Ans. Conventionally a rectangular band which surrounds the
upper part of the valve. Fig. 3.
What kind of a fit is provided between the valve and yoke?
Why?
Ans. A semi-loose fit so that the valve is free to move to and
from the seat so as to adjust itself to the seat.
1026
The Valve Gear


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ECCENTRIC STRAP
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-OFFSET PIN
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ECCENTRIC ROD
ECCENTRIC
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SET SCREW
GUIDE
ECCENTRIC STRAP
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ECCENTRIC
Figs. 1 and 2.-Simple form of valve gear, consisting of eccentric, eccentric
strap, eccentric rod, pin, guide, stem or spindle with adjustable end and yoke.
The Valve Gear
1027
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YOKE

VALVE
Fig. 3.—The valve yoke, or rectangular frame which embraces the box shaped
section of the valve, and to which the valve stem is attached. The valve is
shown in dotted lines to indicate the position of the yoke.
STEM

STEM
1
Fig. 4.—Method of connecting the valve stem to the valve without a yoke. The
stem passes through a circular section cast in the valve, being adjustable by
means of the nuts A, B, at each end.
1028
The Valve Gear

=
ABJUSTMENT
A
YOKE CONNECTION
A
B
STEM OR SPINDLE
ADJUSTMENT
PLUS THREAD
L
Figs. 5 and 6.—Form of valve stem for yoke connection. The length of thread at A, is made sufficient for
adjustment. At C, the stem is enlarged for the guide bearing, there being a forked end which carries the
eccentric rod pin.
ENLARGED SECTION
FOR GUIDE BEARING
B
A
C
ECCENTRIC ROD
CONNECTION
D
C
VALVE SPACE
D
Fig. 7.-Form of valve stem for direct connection without yoke. There are two pairs of adjustment nuts A, A;
the diameter of the rod between the threaded sections is reduced to make a plus thread at the end.

The Valve Gear
1029

ECCENTRIC ROD
T"
THROW
ECCENTRIC.
N
STRAP
E
SET SCREW
10
SHAFT
HUB
I
MG
F
FOR OIL
S
-~
-
17
LINERS
Figs. 8 and 9.-Eccentric strap, and eccentric rod. The eccentric E, is usually secured on the shaft O, by a
set screw I. A groove is turned in the strap to register with a projection on the eccentric so as to prevent side
motion. The strap is in two halves, D, D' and held together by the bolts M, S, liners being inserted between
for adjustment. O, is the center of the shaft, and A the center of the eccentric. O A, is the eccentricity;
A'A or twice the eccentricity A, is the throw. A' A"=T' T", the movement of the valve stem pin.
What is sometimes provided instead of a yoke?
Ans. The stem is sometimes attached direct to the valve with nuts to maintain the
proper distance relation; these nuts provide adjustments for the proper length of the
stem in valve setting. Fig. 4.
Describe the construction of the valve stem?
1030
The Valve Gear
Ans. A typical construction consists of: A, Threaded section
forming a connection to the yoke or valve; B, a cylindrical sec-
tion which passes out of the steam chest through a stuffing box;
C, an enlarged section to secure sufficient bearing area for the
guide; D, a pin which acts as a pivoted joint for the connecting
rod. Figs. 5 and 6.
What is the object of the guide?
Ans. It is to prevent any turning motion and any side move-
ment of the valve stem which might occur on account of the
angularity or action of the eccentric rod.

ECCENTRIC
CONTAINER
0
ECCENTRICITY, OR
1/2 THE THROW.
_8/11
E'
CRANK
Figs. 10 and 11.-Comparison of eccentric and crank. An eccentric is equiva
lent to a small crank whose arm O' E' is equal to the distance O E between
the center of the shaft, and the center of the eccentric. This distance is the
eccentricity, or one-half the throw. Sometimes ignorantly called the
throw by greenhorns.
What duty is performed by the eccentric rod?
Ans. It transmits motion from the eccentric to the valve
stem. Figs. 1 and 2, also fig. 8.
What is an eccentric?
Ans. A crank pin which is so large in diameter that it embraces
the shaft to which it is attached and dispenses with arms. Figs. 8
to 11.
The Valve Gear
1031
What is the object of the eccentric?
Ans. It changes the rotary motion of the shaft into a recipro-
cating motion with proper angular relation to the crank.

How is this motion transmitted?
Ans. By the strap which is connected to the eccentric. The
eccentric rotates within the strap. Figs. 8 and 9.
Describe the construction of an ordinary eccentric?
Ans. It consists of a cast iron disc having a projecting boss
or hub containing a set screw to secure it in any position on the
shaft. A hole for the shaft is drilled out of center or "eccentric"
(hence the name) with the center of the disc.
What is the distance between the center of the eccentric
and the center of the hole called?
Ans. The proper name is eccentricity though it is frequently
ignorantly called the throw by greenhorns. Figs. 10 and 11.
Throw
'1
What is the throw of an eccentric?
Ans. Twice the eccentricity or the amount of to and fro
movement produced.
Angular Advance
What is the angular advance of an eccentric?
The throw is equal to the diameter of the circle described by the
center of the eccentric and not the radius, as ignorantly defined by
greenhorns.
1032
The Valve Gear
Ans. The angle that the eccentric must be moved forward,
(that is in the direction of rotation of the engine) from a posi-
tion at right angles to the crank to give the valve its linear
advance, that is, to move the valve from its neutral position a
distance = lap + lead. Figs. 12 and 13.

NEUTRAL POSITION OF VALVE
LEAD
M
M'
ECCENTRIC
DEGREES
90
CRANK
ANGULAR ADVANCE
-LINEAR ADVANCE
M
A
A
SHAFT
PATH OF ECCENTRIC CENTER
Figs. 12 and 13.-Illustrating linear, and angular advance. When the
crank is on the dead center, and the eccentric set 90° ahead, the valve should
be in its neutral position as shown in fig. 12. The valve, however, when the
engine is on the dead center, must be at a distance (M M', fig. 13) from its
neutral position equal to the lap + lead or in its position of linear advance.
The eccentric then must be turned ahead through an angle AOA', its angular
advance, sufficient to move the valve to its linear advance position M'.
·
Direct and Indirect Valve Motions
What is a direct valve gear?
The Valve Gear
1033
Ans. One in which the valve stem and eccentric rod move in
the same direction, as in figs. 1 and 2.
What is an indirect valve gear?
Ans. One in which the valve stem and eccentric rod move in
opposite directions. Fig. 14.
How is an indirect motion obtained?
Ans. By means of a rocker arm or lever.

JINU
STEM
JOINI
ROCKER
B-
M
Fig. 14. Indirect valve gear. An indirect rocker fulcrumed at A, is used in
place of an offset pin. The valve stem is attached at B, and the eccentric rod
at C. To allow for side motion due to the rocker, a flexible joint is provided at S.
How does the rocker arm reverse the motion?
Ans. One end of the arm is connected to the valve stem, the
other end to the eccentric rod and the fulcrum is located at an
intermediate point.
What do you mean by a fulcrum?
Ans. The point at which a lever is supported or pivoted.
1034
The Valve Gear
What kind of yalve gear has been considered in this
chapter?
Ans. The simple or basic non-reversing valve gear as fitted
to ordinary D slide valve engines.
ROCKER PIN
10%
ROCKER
1
FLY WHEEL

ECCENTRIC PIN
Are there other kinds of valve gear?
Ans. Many.
Fig. 15.-Outside eccentric rod of a high speed engine. With rods of this type,
an eccentric pin is used in place of an eccentric. The other end of the rod is
usually attached to a direct rocker. This and part of the fly wheel are shown
in dotted lines.
21
Name the principal classes of gear.
Ans. 1, Simple (just described); 2, variable cut off; 3, re-
versing; 4, radial; 5, Corliss, etc.
Why are radial valve gears presented in this book?
Ans. Because they are frequently used on steam rollers.
Variable Cut Off
1035
¡
CHAPTER 52
Variable Cut Off
What type of engine is provided with variable cut off
and why?
Ans. The type known as automatic cut off engines as distin-
guished from throttling engines.
What is the reason for variable cut off?
Ans. For economy; any change in the load is met by a change
in cut off.
How is the cut off varied to meet the load?
Ans. It is controlled by an automatic governor.
What are the several methods of obtaining variable
cut off?
Ans. They are:
1. Shifting eccentric;
2. Swinging eccentric offset;
3. Rotating eccentric (independent cut off valve);
4. Fixed eccentric (adjustable lap cut off valve);
1036
Variable Cut Off
5. So called expansion valve gears. *
These various methods may be divided into two classes;
according as the cut off is varied:
1. By single valve gear, or,
2. By double valve gear.
When a single valve gear method is employed, the cut off is called
variable, as distinguished from the methods using double valve gear,
in which case the cut off is said to be independent.
:
Basic Principle
What is the basic principle of varying the cut off of the
ordinary slide valve?
Ans. It is altered by changing both the throw and angular
advance.
In making these changes what is the effect of the valve
motion on the steam distribution?
Ans. The shorter the travel the earlier the cut off.
What may this method of variable advance be called to
fully define it?
Ans. The method of combined variable travel and variable
angular advance. Figs. 1 and 2, also 3 to 5.
*NOTE.-The author objects to the term "expansion valve gears" because
by usage it has come to mean single variable expansion gears as distinguished from
fixed expansion, and double gears, all gears being expansion gears except a few, as
for instance, pump gears, which admit steam for the full length of the stroke.
Variable Cut Off
1037
qu
MALAIKAI}}"
DEERE LIISHG
HEROKEERIMINE
are
SMALL ANGULAR ADVANCE
LARGE PORT OPENING
LATE CUT OFF
How
LARGE THROW
Of
\\\"
SMALL THROW
LARGE ANGULAR ADVANCE
SMALL PORT OPENING
INCREASE IN ANGULAR ADVANCE
LAP
EARLY CUT OFF
Figs. 1 and 2.-Diagrams illustrating the principle of variable cut off. To change the cut off with a
single valve, both the throw and angular advance must be altered. This is the method of com-
bined variable throw and variable angular advance and is the one employed on all single valve
"automatic cut off" engines. It is frequently and erroneously called the method of variable travel, thus, the
cut off is said to be shortened by reducing the travel. Figs. 3 and 4 show why this is wrong.

1038
Variable Cut Off

What two methods are used in moving the eccentric to
vary both the travel and angular advance?
Ans. 1, By shifting; 2, by swinging.
In construction, what do they call the mechanism to
distinguish the two methods?
Ans. 1, Shifting eccentric; and 2, swinging eccentric.
i
LEAD
LEAD
DISTURBED
LEAD
UNCHANGED
T
LAP+LEAD
LYLINEAR ADVANCE)
€
||||
buffal
ANGULAR ADVANCE
LATE CUT OFF
TO
THROW (LATE CUT OFF)-
DECREASE IN
ECCENTRICITY FOR
EARLY CUT OFF
TO
THROW (EARLY CUT OFF).
ANGULAR ADVANCE
EARLY CUT OFF
o
HO
THROW (EARLY CUT OFF),
"
E
Figs. 3 to 5.-Diagrams showing why both the throw and angular ad-
vance must be varied to change the cut off. In the figures let O, be the center
of the shaft, and E, the center of the eccentric for maximum throw, then NO E,
is the angular advance for maximum throw. Now, if only the throw be changed
as in fig. 4, the center of the eccentric will be at some point E' on radius O E'
evidently this reduces the linear advance L A, to L'A', thus disturbing the
lead. Hence, when the travel is changed, as by reducing the eccentricity
from OE to OE', figs. 3 and 4, the angular advance must be increased from
NOE, to NOE", fig. 5, in amount sufficient to maintain the linear advance
constant in order not to alter the lead.
Variable Cut Off
1039
Which arrangement is preferable and why?
Ans. The swinging eccentric gear because of less friction of
the moving parts.

LATE CUT OFF
POSITION
STRAIGHT SLOT-
CRANK PIN
SHAFT
EARLY CUT OFF
POSITION
C
es!
S
D
IN
LINEAR
ADVANCE
E
BEARING
E
M'
M
C
B BEARING
Ò
Fig. 6.-The shifting eccentric. Two arms A, B, attached to the eccentric, pass
through the bearings C, D. The eccentric has a slot S to permit linear move-
ment on the shaft. By shifting it from E to E', the throw is reduced, and the
angular advance increased, the combined effect of which produces an earlier
cut off. There is considerable movement and friction in the bearings C, D, as
compared with the swinging eccentric. The lead is constant (not considering
the angularity of the eccentric rod). For a late cut off (full gear) the position
of the eccentric is shown in full lines with its center at E. In this position O M,
is equal to the eccentricity, or half the throw, and NO E, the angle of advance.
The cut off is shortened by reducing the throw and increasing the
angular advance. This is done by shifting the eccentric along the slot to
some intermediate position as that shown by the dotted lines with center at E'.
This reduces the eccentricity, or half throw from O M, to O M', hence, the
travel of the valve has been reduced twice the distance M M', and the cut off
shortened an amount corresponding with the increase (E O E') in the angular
advance.
1040
Variable Cut Off
V
The Shifting Eccentric
How is a shifting eccentric constructed?
Ans. A straight slot is cut in the eccentric at right angles to
the crank, as in fig. 6, two arms project from the eccentric and
work in bearings attached to the fly wheel thus permitting the
eccentric to shift along an axis at right angles to the crank.

The shaft passes through the slot and the latter is made long enough
to vary the throw sufficiently to obtain the desired range of cut off.

7827
Fig. 7.-Example of shifting eccentric as used on a traction engine. As seen
the shifting eccentric slides in V, grooves, being geared to a double bell
crank, which is connected by a link to a disc and collar arranged to slide
along the shaft. A second bell crank and rod connect the collar with the
control lever.
How is the cut off shortened?
Ans. By reducing the throw and increasing the angular
advance.
How is this done?
Ans. By action of the governor in "shifting" the eccentric
along the slot to some intermediate position.

Variable Cut Off
1041
What is the effect upon the lead in varying the cut off
with the shifting eccentric?
Ans. Since the center of the eccentric moves in a line at right
angles to the crank the lead remains constant not considering
angularity of the eccentric rod.
What in detail is the action of a shifting eccentric in
shortening the cut off?
Ans. It shortens the cut off by reducing the throw and in-
creasing the angular advance sufficiently to maintain a constant
linear advance (not considering the angularity of the eccentric rod).
The Swinging Eccentric
What prompted the introduction of the swinging eccentric?
Ans. It was designed to overcome the chief objection to the
shifting eccentric, that is, the considerable movement and fric-
tion in the bearings, the latter being liable to interfere with the
free movement of the eccentric, and thus reduce the sensitive-
ness of the governor especially on account of the difficulty of
lubricating a bearing rotating around a center.
On account of the objections just mentioned, what is
the special application of the shifting eccentric?
Ans. It is suitable for an adjustable or non-automatic cut-off
engine.
Describe the construction of a swinging eccentric.
Ans. A swinging eccentric has one arm of any convenient.
ength and pivoted at some point on a line joining the shaft and
rank pin centers. Fig. 8.
1042
Variable Cut Off
What is the pivot called?
Ans. The swing center.
What kind of slot is cut in the eccentric?
Ans. A curved slot having sides in the form of concentric arcs
of circles described with the swing center as center.
What is the action of the swinging eccentric in short-
ening the cut off?

CRANK PIN
B
ARM
LATE CUT OFF
A
SWING CENTER
EARLY CUT OFF
S
N
EL
E
HEY
M' M
\\
8'
Fig. 8.-The swinging eccentric. The arm A, is pivoted at B, in line with the
shaft and crank pin. This location of the swing center causes the lead to
increase as the cut off is shortened. If the swing center be located on the
opposite side at B', the lead will decrease as the cut off is shortened. The
action is similar to that of the shifting eccentric, that is, the cut off is shortened
by a reduction of throw and an increase of angular advance. This
is done by swinging the eccentric about the swing center B, from its full
gear position E, to some intermediate position E'. Here, the angular advance
has increased from N O E, to N O E', and the throw reduced by twice the
distance M' M.
It should be noted in fig. 8, that as the center of the eccentric is moved
from E to E', to shorten the cut off, the lead is increased an amount equal to
the distance L. Taking into account the angularity of the eccentric rod, the
actual increase in the lead is slightly less than the distance L.
Variable Cut Off
1043
[/(0)!!!!
Ans. It shortens the cut off by reducing the throw and increasing
the angular advance in such proportion as to give an increasing
lead.

W
SWINGING
ECCENTRIC
|||||||||

GOVERNOR
அம்
SWING
CENTER
Fig. 9.-Fly wheel and governor of Buffalo engine illustrating the swinging
eccentric. It should be noted that in the design here illustrated the swing
center is near the radial slot instead of at the end of the arm as in fig. 8.
How would the action of the swinging eccentric be modi-
fied if the swing center be located on that side of the
shaft opposite the crank pin?
Ans. The lead would decrease as the cut off is shorter
Why is this objectionable?

1044
Variable Cut Off
Ans. Because it reduces the port opening as the cut off is
shortened, thus producing wire drawing which lowers the
admission pressure.
The Offset Swinging Eccentric
What is the offset swinging eccentric?
Ans. An arrangement on some engines in which the swinging
eccentric is located with its swing center offset from the line joining
the shaft and crank pin centers. Fig. 10.
RADIAL SLOT
LATE CUT OFF
SWING CENTER
CRANK PIN
B
OFFSET
EARLY CUT OFF
S
IN
E
E
MM
E"
=====
Fig. 10.-The offset swinging eccentric. With the swing center located as i
the figure, the lead is the same for maximum and minimum cut off and greates
in mid position. The swing center B, is offset above the crank axis one-hal
the distance from E, to this axis. This position B, gives the same lead in the
two extreme positions, and it should be noted that the total increase of lead L
is only one-half the increase L, of fig. 8. The two positions illustrated, corres
pond to those of the two preceding figures showing the same angles of advanc
but less increase of lead. From the figure it is seen that if the eccentric b
moved to the extreme position E", the lead will decrease and become equa
to the original amount for the full gear position E.
Variable Cut Off
1045

We
MALZE
1. Slow and insufficient opening of the port for admission
2. Pre-release occurs too early
LAS IZ:
[1]WH
| *«** (*
INCREASE IN ANGULAR ADVANCE
ECCENTRIC AT END OF THROW
BEFORE PORT IS FULLY OPENED
3. Compression begins too early
ད་།་
THROW FOR LATE CUT OFF
THROW FOR EARLY CUT OFF
LINEAR DISPLACEMENT CAUSING
PREMATURE PRE-RELEASE
LINEAR DISPLACEMENT CAUSING
PREMATURE COMPRESSION
A
A
71
Figs. 11 to 13.-DEFECTS OF THE SLIDE VALVE AT EARLY CUT OFF:
1, fig. 11, slow and insufficient port opening. Note that the eccentric
center E', is at the end of its throw; hence the valve movement in opening the
port is comparatively slow; 2, fig. 12, pre-release occurs too early. This
is due to the increased angular advance displacing the valve to the left by
1046
Variable Cut Off
What is the object of offsetting the swing center?
Ans. To compromise between the conditions described in the
last two types, that is, instead of an increasing or decreasing
lead, by offsetting the swing center the same lead is obtained at

Q
LATE CUT OFF
HNCREASE IN LEAD (EARLY CUT OFF)
-NORMAL LEAD (LATE ĆUT OFF)
B
A
CAUSE OF
INCREASE IN LEAD
:
E
B
E
E'
EARLY CUT OFF
SWING CENTER
Figs. 14 and 15.-DEFECTS OF THE SLIDE VALVE AT EARLY CUT OFF:
4, lead not constant with_swinging eccentric. Case I. Swing center
between shaft and crank pin. For early cut off, the center E, of the eccentric
swings through the arc E E', fig. 15, to position E', thus increasing the angu-
lar advance and reducing the travel, but in so doing, the valve is displaced
to the right a distance Ă B, increasing the lead by this amount.
Figs. 11 to 13.-Text continued.
the distance A B; 3, fig. 11, compression begins too early. Similarly as
in 2, the increased angular advance displaces the valve to right by the
distance A' B', causing the valve to close to exhaust too soon. In the figures,
E, is the center of the eccentric for full gear or late cut off, and E', for early
cut off.
Variable Cut Off
1047
both maximum and minimum cut off with a somewhat larger lead
in mid-position.
What is the action of the offset swinging eccentric in
shortening the cut off?
AB
Ans. It shortens the cut off by reducing the throw and in-
creasing the angular advance in such proportion that the lead
increases for full gear to mid position and then decreases to the

AW:
===
LEAD WITH LATE CUT: OFF
DECREASE IN LEAD
LEAD WITH EARLY CUT OFF
A
Of
Of
ECCENTRIC
CENTER
SWING ARM
SWING CENTER
DECREASE AB IN LEAD
DUE TO CHANGE IN ANGULAR
POSITION OF SWING ARM
(O
AB
E
SWING ARM
SWING CENTER
Figs. 16 and 17.-DEFECTS OF THE SLIDE VALVE AT EARLY CUT OFF:
5, lead not constant with swinging eccentric. Case II, swing center
and crank pin on opposite sides of shaft. When the center of the eccentric
swings through the arc E E', fig. 17, to shorten the cut off, the valve is dis-
placed to the left a distance À B, thus decreasing the lead by this amount.
1048
Variable Cut Off
original amount at minimum cut off, the total increase being less
than that produced by the swinging eccentric.
For best economy what is the range of cut off required
for a single cylinder engine?
Ans. Approximately from 1/3 to 1/5 non-condensing and
from 1/5 to 1/7 condensing, depending upon initial pressure,
quality of the steam, etc.

U
A
B
C
Fig. 18.-The Gonzenbach independent cut off valve. This is located in a sepa-
rate steam chest above the main valve, the latter being an ordinary slide
valve which controls the steam distribution with the exception of cut off. The
range of cut off is limited, and the lower steam chest presents a large clearance
which is objectionable. Moreover, the main valve is inaccessible. In the figure,
the main valve, which is the lower, is an ordinary slide valve; the cut off valve
which works on a ported partition directly above, is of the gridiron type, that
is, there are a number of steam ports (A, B, C,) in order to secure a quick cut
off with moderate travel. During admission, steam passes through the ports,
A, B, C, into the lower steam chest and to the cylinder through either one of
the cylinder ports which happens to be open. The action of the cut off valve
differs from the ordinary valve in that while the latter opens and closes the
port with the same edge, the cut off valve does this with the two edges, that
is, the port in the valve passes bodily across the port in the seat.
Variable Cut Off
1049
Why is such considerable range of cut off required?
Ans. Because of variations in power demands.
What are the defects of variable cut off by the methods
based on changing both the throw and angular advance,
for very early cut off?
Ans. 1, Slow and inadequate port opening; 2, pre-release occurs
too soon; 3, compression begins too early; 4, lead not constant.
How may these defects be overcome?
Ans. By the method of independent cut off.

Independent Cut Off
What do you understand by the term independent cut off?
Ans. It relates to a variable cut off valve gear which employs
two valves: 1, A main valve which controls admission release
and compression; and 2, a cut off valve which controls the cut off.
Where is the cut off valve located?
Ans. 1, In a separate steam chest*; or 2, in the same steam
chest arranged to work on the back of the main valve.
What may be said in favor of the first arrangement?
Ans. Nothing; no good.
What is the second arrangement called and why?
Ans. The riding cut off because the cut-off valve rides on
he back of the main valve.
*NOTE,-Known as the Gonzenbach independent cut-off valve.
:
1050
Variable Cut Off
The Riding Cut Off
Of what does the riding cut-off gear consist?
Ans. A main valve with steam passages carried to the back
which forms a seat for the cut-off valve.
A
NEGATIVE LAP

STEAM PORTS
Fig. 19.-Gonzenbach cut off valve in neutral position showing negative lap.
The cut off is varied by turning the cut off valve eccentric forward or backward
on the shaft as the case may be. The figure shows the cut off valve in its neutral
position from which it is seen that the valve has negative lap. This may equal
or exceed the width of the ports in the seat; the negative lap being the dis-
tance A, measured from one edge of the seat port to the opposite edge of
the valve port.
The principles of the Gonzenbach valve are best understood by the appli
cation of the Bilgram diagram.
What three methods are employed for obtaining variable
cut off with the riding valve?
Ans. By the methods of: 1, Variable angular advance
2, variable lap; 3, variable travel.
Describe the method of variable angular advance.
Ans. It employs a rotating, or loosely journaled eccentric fo
the cut-off valve whose angular advance is controlled by a
governor.
Variable Cut Off
1051
Describe the second method.
Ans. This method has a fixed eccentric to operate the cut off
or “riding” valve, the lap of the latter being adjustable by a
right and left screw.
How about the third method?
Ans. A link is used to vary the travel.
MAIN VALVE ----
RIDING CUT OFF VALVE-
STEAM EDGE·
NEG. LAP

STEAM
EDGE
STEAM EDGE
STEAM EDGE
"l
Fig. 20.-Riding cut off valve with outside cut off edges. In operation the
cut off valve travels or "rides" on top of main valve, and with fixed lap as
above, receives its movement 1, from a rotating eccentric, that is, an eccentric
loosely journalled on the shaft so that its angular advance may be changed
to vary the cut off, under control of: 1, a governor, or 2, a fixed eccentric with
link motion. The riding cut off valve with outside cut off edges gives
quickest cut off with early cut offs.
STEAM PASSAGE
SE

ig. 21.-Riding cut off valve with inside cut off edges. This arrangement
having inside cut off edges gives quickest cut off with late cut offs.
1052
Variable Cut Off
Riding Cut Off
(1. With variable angular advance)
See figs. 20 to 41.
How is the cut off shortened?
Ans. By increasing the angular advance.
CM O CR

A-
NEUTRAL
STEAM PASSAGE
I'H'
wif
STEAM EDGE
D'
E
G
POSITION
CM
EXTREME
POSITION
B
Scale: half size
B'
Figs. 22 and 23.-Detail of main valve and seat. On A B, lay off the stean
port CE=¾ in., the port opening C D = % in., and the bridge E F = ½ in
Sketch in valve end in extreme position. D, will be the steam edge. Lay of
D H=¾ in. and draw D D', and H H', giving the steam passage througl
the valve. This is usually made same size as the port to reduce friction. II', the
end of the valve is located far enough beyond HH', to give a steam tight joint
say ½ in. Locate G, the exhaust edge of the valve, so that D G-lap + por
=
5/16 in. +34 in. The edge G', of the bridge is so located that G G'=CE
The center line OO, is now drawn half way between F and G'. Transfer th
detail of valve end thus found to A' B', showing it in neutral position, an
complete the valve and seat as shown.
Variable Cut Off
1053
CR CR ÇM
→→→ 12
"
1/5 CUT OFF
Scale: half size
E5 C.O.
-DEM
Fig. 24.-Position of main and riding valves corresponding to crank position for 1/5 cut off. At the right is
shown the crank position O E, and center of main eccentric Em, whose angular advance is obtained from
the Bilgram diagram. ER, is the center of the eccentric of the riding valve. Both valves are shown in the posi-
tions corresponding to those of the eccentrics, CR, being the center of the riding valve, and CM, the center
of the cut off valve. Clearly, the valves are displaced with respect to each other the distance CR CM. The
main valve is moving to the right, and the riding valve to the left. From the position of the eccentrics it is
clear that the main valve is practically at rest and the riding valve traveling at maximum speed.
How is the port opening affected?
Ans. It decreases as the cut off is shortened.
What is the nature of the cut off?
Ans. At late cut off it is "sluggish," increasing in sharpness with the degree of
expansion.

1054
Variable Cut Off
+½"+
는
​D
D
O"
OCR ÇM
Scale: half size
1/5 C.O. SETTING
E½" P.O.
Ем
ER
Fig. 25.-Position of valves when the riding valve has opened the port a distance C' D'½ in. with 1/5 cut
off setting. Draw the dotted parallel lines C' C and D' D', then C' D'C D", from which it is seen that the
main valve has opened a distance C D, less than C D". Hence, the effective port opening is less than 2
in. for the cut off setting of the riding eccentric, and the design accordingly does not meet the requirement.
Some modification must be made, as shown in figs. 26 and 27.
How about the virtual travel?
Ans. It increases as the cut off decreases.
What do you mean by the virtual travel?
Ans. The actual travel of the riding valve on the main valve regarding the main
valve as stationary.

Variable Cut Off
1055

0
ONCR
CM
VA
V
1/5 CUT OFF
E '5 C.O.
ヨ
​ER
M
Figs. 26 and 27.-Position of modified main valve and
riding valve at 1/5 cut off. A detail of one end of main
valve is shown in fig. 27 in extreme position from which
the complete valve is drawn in cut off position. The relative
positions of the two eccentrics Em and Er, are seen at the
right, which also shows the difference in the throws of the
two eccentrics.
1056
Variable Cut Off

1/2+
C' D
O CR CM
1/5 C.O. SETTING
E-1/2" P.O.
Scale: half size
Fig. 28.-Position of modified main valve and riding valve when the riding valve has opened the port a
distance C' D'½ in. with 1/5 cut off setting. Transferring the port opening C' D', to the valve seat by the
dotted lines it is seen that the main valve port opening CD, is the same as the riding valve port opening
C' D', hence, the effective port opening is C' D', or ½ in. as required.
CR O CM

Fig. 29.-Positions of valves and eccentrics for % cut off.
78 CUT OFF
ER
EM
Em
E8 C.O.
Variable Cut Off
1057


Buff
Op CR GM
you to
O
Fig. 30.-Positions of valves and eccentrics for ½ cut off.
Scale: half size.
1/2 CUT OFF
Goo
CR GM
7/8 C.O. SETTING
Fig. 31.-Positions of valves, crank and eccentrics for ½ in, port opening of
the riding valve with 8 cut off setting of the riding eccentric.
E2" P. O.
E2½ C.O.
ER
Scale:
half size
1058
Variable Cut Off
1/2
O CR CM
WIDTH OF END BRIDGE
B⋅
K
Fig. 32.-Positions of valves, crank and eccentrics for ½ in. port opening of the
riding valve with 2 cut off setting of the riding eccentric.
2 C.O. SETTING
A
E½"P.O.
NEGATIVE LAP CR
OR
LINE AND LINE CR
CM ZERO OVERTRAVELA+B
میں ہیں
См
✓
Figs. 33 and 34.-Detail of one end of valves showing that the half travel of
the riding valve on the back of the main valve or virtual half travel for
zero over travel is equal to riding negative lap+end bridge width.
Fig. 33, shows both valves in neutral position, and 34, valves in position of
zero over travel.
Scale:
half size
G
EM


Variable Cut Off
1059

VIRTUAL
ECCENTRIC
NEGATIVE LAP
E'
EJ
CR
90°
Сајс
بھی
VIRTUAL THROW
VIRTUAL.
ANGULAR
(ADVANCE

Figs. 35 to 37.—The virtual eccentric. By definition: the virtual eccentric is
an imaginary eccentric of such throw and angular advance that
if keyed to the main shaft and connected with the riding valve,
would give it a movement over the main valve (regarded as at rest)
precisely the same as it has when both valves are moving. Fig. 36
shows both valves in neutral position, and in the diagram fig. 35, O E', is the
crank position of cut off for zero overtravel. With a radius equal to virtual
1060
Variable Cut Off
Features of Riding Cut Off with Variable Angular Ad-
vance.
A study of the example just given will show certain
characteristics of the gear which are in brief:
1. Increasing the angular advance of the riding eccentric shortens the
cut off.
*
2. The cut off is “sluggish" for late cut off, increasing in sharpness
with the degree of expansion.
!
3. The effective port opening decreases as the cut off is shortened.
4. The virtual travel increases as the cut off decreases.
Buf
Riding Cut Off
(2. With variable lap)
What name is given to this type of riding cut off and
why?
Ans. It is called the Meyer cut-off gear after the inventor.
Describe the Meyer gear.
Ans. It consists of a main and a riding valve, the latter divided
into two plates or blocks connected by a right and left handed screw,
the screw serving as a valve spindle and as a means of varying
the lap.
**
Figs. 35 to 37-Text continued,
eccentricity for zero overtravel describe a circle whose center is o. The diameter
of this circle will be the throw of the virtual eccentric, or virtual throw. For
cut off at o E', evidently the riding valve must move to the left a distance
equal to the negative lap. Hence, lay off o B = negative lap, and project
down the dotted line cutting the virtual throw circle at Ev. Ev then is the center
of the virtual eccentric, and its eccentricity is equal to o Ev, for the setting
giving zero over travel.
Variable Cut Off
1061
Scale:
half size
7/8 C.O.
SETTING
V2 C.O.
SETTING
V5 C.O.
SETTING
EN ERER..
3 Colu
CR
CR
CR
EM

CM
CM
مجی
CM
X
How does the riding ec-
centric differ from the
variable angular advance
eccentric as in type 1?
Ans. It is fixed and usually
has a throw greater than
that of the main eccentric.
What angular advance is
given to the riding
eccentric?
Ans. Its angular advance
is 90° for reversing engines
and a little less than 90° for
engines which run in only
one direction.

In this gear as in all rid-
ing gears, when does cut
off take place?
•

Figs. 38 to 41.-Detail of valve
ends with riding valve at end of
virtual travel, showing undertravel
for % and ½ cut offs, and over-
travel for 1/5 cut off. In fig. 38 im-
agine Emas center of main eccentric,
fixed in such position that the main
valve is in the neutral position, then Er, E', and E", are centers of virtual eccentric
for the riding valve for throws corresponding to %, 2 and 15 cut off respec-
tively. As shown, the virtual eccentrics are at one end of the throw displacing
the riding valve a distance equal to ½ the virtual travel.
1062
Variable Cut Off
3/4 CUT OFF
½ CUT OFF
16 CUT OFF
CR
ZA
O
O GR
-+-
Cm
بھی
CM || CR E6
E2
ய
EB
E

En
EM
Ем
Scale: half size
Figs. 42 to 44.-Positions of valves, eccentrics and crank for 34, 2 and %
cut off. By noting the positions of the eccentrics it is evident that as the cut off
is shortened it becomes sharper. Figs 42 and 43 show valves moving in same
direction, and fig. 44 valves moving in opposite directions.
Variable Cut Off
1063

34 C.O. SETTING
A
CR ÇM
V2 C. O. SETTING
V6 C.O. SETTING
Scale: half size
O
O
CM CR
См
GR
Ем
ER
QEM
EA
-дем
EA
Figs. 45 to 47.-Positions of valves, eccentrics and crank for mid-admission
corresponding to ¾, ½, and % cut offs, showing effectvie port opening at
these positions.
1064
Variable cut off
Ans. When the riding valve is at a distance from the center of
the main valve equal to its lap.
That is when the steam edge of the riding valve is line and line
with the steam edge of the "bridge" of the main valve.
What is the effect of increasing the lap of the riding
valve (that is, moving the blocks apart)?
Ans. It shortens the cut off.

A
B
S
OH
LIT
OL
W
ADJUSTABLE ARM
Fig. 48.-Independent cut off adjustment for link motion. On marine engines,
an independent adjustment for cut off is frequently fitted to the high pressure
cylinder valve gear, and sometimes to each cylinder. With link motion the inde-
pendent adjustment as shown, consists of an arm A, keyed to the reverse shaft
and having at its end a slot B, within which works a block with screw S, operated
by turning the squared end W.
What is the character of early and late cut off?
Ans. It is "sluggish" for both early and late cut offs, but
somewhat improved for intermediate cut offs.
Variable Cut Off
1065
How does shortening the cut off affect the port opening?
Ans. Shortening the cut off decreases the port opening.
SEAT LIMIT
How is re-admission avoided?
Ans. By the proper location of the center of the riding
eccentric.

SEAL
G
W
Fig. 49.-Seat limit for Meyer valve.
HALF TRAVEL
GM
Scale:
half
size
Į
From the example just given illustrating the design of Meyer
gear for a marine engine, it will be noted that:
1. Increasing the lap of the riding valve (that is, moving the blocks apart)
shortens the cut off;
2. The cut off is "sluggish" for early and late cut offs, but somewhat
improved for intermediate cut offs;
3. The effective port opening decreases as the cut off is shortened;
4. Where very early cut off is desired, the main valve should be designed
for large port opening, to secure adequate effective port opening at early
cut off;
5. For reversing engines, the angular advance of the riding eccentric
should be 90° to secure symmetrical distribution for both forward and
reverse motions;
6. For engines running in only one direction the angular advance of
the riding eccentric is usually a little less than 90°;
7. Re-admission is avoided by the proper location of the center Q', of
the riding eccentric;
8. The length of main valve may be reduced by shortening the latest
cut off of riding valve.
1066
Variable Cut Off
E6 C.O.
E.O. C.O
Q₁
LATEST
CUT OFF
7
A
Q46
CUT OFF
Qo
ZERO
C.O.
B
EL.C.O.
Qo
QUE
M

Qu
Scale: half size
T
Figs. 50 to 53.-Bilgram diagram for
riding cut off with variable travel and
positions of valves, eccentrics and crank
for latest, one-sixth and zero cut offs.
LAP AND LEAD
CR CM
O
CR CM
Q CR CM
0
ER
Ем
ER
EM
DEM
Variable Cut Off
1067

F
E
QL
LATEST
C.O.SETTING
QYA
44 C.O.
SETTING
QY6
% C.O.
SETTING
Ja
Voi
QYO,
O
CM CR
CRCM
CRCM
'Scale: half size
F
E
ERT
Ем
الاد
Ем
ER
Figs. 54 to 57.-Bilgram diagram and positions of valves, eccentrics and crank
for mid-admission corresponding to latest, one-sixth and one-fourth cut offs,
showing effective port opening. The diagrams show the gradual reduction in
port opening as the cut off is shortened, a defect inherent in this type of
variable cut off gear.
1068
Variable Cut Off
jer
Riding Cut Off
(3. With variable travel)
See figs. 50 to 57:
How is the travel varied with this method?
Ans. A link is used to vary the travel.
How is the cut off affected when the travel is reduced?
Ans. Reducing the travel shortens the cut off. Figs. 49 to 56.
For a given angular advance and travel of the riding
valve upon what does the latest cut off depend?
Ans. Upon the lap of the riding valve.
What is the characteristic of the port opening?
Ans. The port opening decreases rapidly as the cut off is
shortened.
What is the characteristic of the cut off with respect to
sharpness?
Ans. Sharpness of the cut off decreases as the cut off is
shortened.
A study of figs. 50 to 57 indicates the following characteristics
of this gear:
1. Reducing the travel of the riding valve shortens the cut off;
2. If the range of cut off be up to zero, the negative lap must be equal to
lap plus lead of the main valve;
3. For given angular advance and travel of the riding valve, latest cut off
depends on the lap of the riding valve;
4. The effective port opening decreases rapidly as the cut off is shortened;
5. Sharpness of the cut off decreases as the cut off is shortened.
Reversing Valve Gears
1069
CHAPTER 53
Reversing Valve Gears
Name the various methods of reversing.
Ans. 1, Loose eccentric; 2, link motions; 3, radial motions, etc.
1. Loose Eccentric
What is the principle of reversing by a loose eccentric?
Ans. It consists in rotating the eccentric around the shaft until
It has the proper angular advance for reverse motion.
What is the proper angular advance for reverse rotation?
Ans. A reverse angular advance equal to the forward angular
advance.
That is, for clockwise rotation, advance the eccentric clockwise 90°
+angular advance.
4
For reverse or counter-clockwise rotation, advance the eccentric
counter-clockwise 90° + angular advance.
Describe the construction of simple loose eccentric gear.
Ans. The eccentric is loose on the shaft between a fixed collar
1070
Reversing Valve Gears
and a hand wheel. A stud projecting from the eccentric and
passing through a curved slot in the wheel is provided with a
clamp to fasten the stud in position by a hand nut. When the
stud is clamped at either end of the slot the eccentric is in
position of forward angular advance or reverse angular advance.
FORWARD
M
FORWARD
ANGULAR
ADVANCE
+


A
REVERSE
ANGLE OF
ROTATION
Á
?
REVERSE
ANGULAR
ADVANCE
A.
Figs. 1 and 2.-Simple method of reversing an engine. By rotating the eccentric
on the shaft so that it will have a reverse angular advance A'O E' (fig. 2),
equal to the forward angular advance A O E (fig. 1), the valve will be moved
from M to M', and the engine will run in the reverse direction. The arrows
show the steam distribution.
Reversing Valve Gears
1071
2. Link Motion
What is a link motion?
Ans. A name given to the arrangement of eccentric rods, link,
hangers, reach rods and rocking shaft, by which the relative
COLLAR
ECCENTRIC
HAND WHEEL.
A
B
E
C
E
A
F
F
t

H

Figs. 3 and 4.-Loose reversing eccentric; an application of the principle
illustrated in figs. 1 and 2. The eccentric E, is free to turn on the shaft and is
held in position by a stud and hand nut F. The stud passes through a circular
slot in the wheel, so located that when the stud is clamped at one or the other
end, the eccentric is in correct position for forward or reverse motion of the
engine.
position and motion of the valve are changed at will, thus pro-
viding for either forward or backward motion, and for varying
rates of expansion of the steam.
1072
Reversing Valve Gears

BEARING
Hi h
BEARING
B
E
all'ul
VALVE SHAFT
MAIN SHAFT
S'
S
L.P. CYL
SLEEVE
M V P
#E
UNAMUUYOKatiments.
th
HP CYL.
COLLAR
R
GEAR
WHEELS
Fig. 5.-Loose reversing eccentric gear; marine type as applied to multi-cylinder
engines with valves on the side. The principle of reversing is the same as in figs.
6 and 7, that is, it is accomplished by the action of the pins P, P', attached to
the reverse rod R, in moving the length of the spiral and straight slots. C, collar
on sleeve; E, E', eccentrics; G, G', gear wheels; H, straight slot; M, curved
slot; P P', pins; R, shift shaft, S, main shaft; S', valve shaft.
-ECCENTRIC
E
P
Pi
M
M
G'
SLEEVE
ROD
الاسالت
R
O

M
S
H
P
P'
Figs. 6 and 7.-Loose reversing eccentric; marine type. In construction, the
eccentric E, is keyed to a sleeve V, which fits so as to easily revolve on the
main shaft S; any movement in the direction of the shaft is prevented by the
bearing B, and collar C. A spiral slot M, is cut in the sleeve and hole bored in
the end of the shaft to H. A straight slot is cut through a portion of the bore
from H, to the other end of the spiral slot. The rod R, works in the bore and
Reversing Valve Gears
1073
What was a very extensive use of the link motion?
Ans. On locomotives.
SPUR OR HERRINGBONE GEAR
ECCENTRIC
BEARING
Wild Pokus“ (se
-4

RACK AND
BEARING PINION
P
[cat
CONTROL WHEEL

RACK
R
+
P
CLAMP
PINION
-BEARING
Figs. 8 and 9.-A second method of control for loose eccentric reversing gear.
In fig. 8, the portion of the reverse gear shown is the same as in fig. 7. In
construction, a series of teeth are cut in the end of the rod forming a circular
rack which engages with the pinion P. The latter is pivoted underneath as
shown in fig. 9, and the rod provided with a bearing to hold it in proper
engagement with the pinion. Attached to the pinion is a shaft having at its
other end a hand wheel. In operation the reverse rod R, may be moved to
forward or reverse position by the hand wheel and secured in position by the
clamp. The construction and operation are clearly shown in the two views.
What name is usually and ignorantly given to the link
motion and why?
Ans. They call it the "Stephenson" link motion*. (See next page)
Figs. 6 and 7.—Text continued.
has attached to its end cross pins P, P', which pass through the shaft and sleeve
slots. To change the position of the eccentric R, is moved, which by the action
of the pins in traveling the length of the slots causes the sleeve and eccentric
to rotate on the shaft, thus changing the angular advance. By giving the
spiral slot the proper pitch, the eccentric may be rotated through the correct
arc when P, is moved the length of the slot to reverse the motion of the engine.
1074
Reversing Valve Gears
REVERSE
D
L
P
(G
1 MID-GEAR
L
1
F
سنا
my
S' S
//
H
B
:R'
E
M
P
REVERSE LEVER

FORWARD
WA
QUADRANT
VALVE STEM
A
R
C
CRANK
Fig. 10.-The alleged
Stephenson or shift-
ing link. Called
shifting to distinguish
it from the Gooch
link. It consists of a
link L, block M, two
eccentrics E,E', and
eccentric rods R, and
R', which are pivoted
to the link at A and
B. The valve stem has
a forked end, and is
pivoted to the block
by the pin P. Reach
rods S and S', (one
on each side of the
link) connect the lat-
ter with a notched
quadrant H, and
latch which retains it
in any position. The
link which consists of
two curved bars
bolted together at the
ends, freely slides on
the block when the
reverse lever is
moved, and to a lim-
ited extent in opera-
tion.*
The right
*NOTE.
name for it is the Howe
link motion. Howe invent-
ed it and the manager of
Stephenson's Locomotive
Works showed it to Steph-
enson who at once saw the
worth of its application,
approved of it, and got the
credit for it-either it was
forced upon him or he stole
it, anyway illegitimately
it is known as Stephenson's
link motion and nothing
can be done about it.
Reversing Valve Gears
1075
Name a defect of the link motion at early cut off.
Ans. Port opening is decreased and the amount depends upon
the amount of port opening at full gear (latest cut off) †.
†NOTE.-With port opening at full gear greater than the width of the port,
fairly good admission may be obtained cutting off as early as 4 stroke.
How early may steam be cut off with the link motion?
Ans. It depends upon the amount of port opening at full
gear. For instance extreme practice for locomotives is excessive
D'
D
G
S'

C'
S
P
Fig. 11.-Plan of shifting link showing double reach rods S and S'. With two
rods there is no lateral or twisting strain on the stem in reversing;
this is a point well worth noting by anyone intending to purchase an engine,
the offset form of construction being objectionable. The reach rods are pivoted
to the link at C,C', and to the reverse lever G, at D,D'. P is the valve stem pin.
*NOTE.-In fig. 10, if the block be at one end of the link, the motion of the eccen-
tric attached to that end of the slot is transmitted to the valve; when the block is at
some intermediate position, the valve receives the combined motion of the two eccen-
trics; if the block be at the middle of the slot, or mid-gear position, the valve does not
admit steam to the cylinder. As shown in the figure, the block is at that end which is
attached to the forward eccentric E, hence the engine runs in a forward direction. By
moving the reverse lever to G", the link slides to the right until the other end P', which
is attached to the backward eccentric E', is in contact with the block. The valve then
partakes of the motion of this eccentric and the motion of the engine is reversed. With
the reverse lever in any intermediate position between full gear and mid-gear, the cut
off is shortened, because the motion of one eccentric tends to counteract that of the
other; the combined effect is to reduce the travel of the valve.
1076
Reversing Valve Gears
I
port opening at full gear, fairly good admission being obtained
cutting off early as 14 stroke.
Why is the link slot curved?
Ans. To equalize the lead of the valve for all travels.

B
B
A
B
A
A
B
Figs. 12 to 15.-Movement of the link during one revolution. The figures show
the positions of the link gear when the crank C is on the dead center, and at
1¼, ½ and ¾ of a revolution. The point of suspension being at the center, as
on locomotives, the slip is considerable.
Reversing Valve Gears
1077
What do you mean by "equalizing the lead"?
Ans. To make the increase or decrease of the lead the same
for both strokes of the piston.

Mom
LEAD
INCREASE
FULL GEAR
MID GEAR.
OPEN
RODS
Figs. 16 and 17.-Diagrams illustrating why open rods give increasing lead.
In shifting the link from full to mid gear, the angularity of the rods is so
changed that the valve stem pin P, and valve are moved to the left a distance
L, thus increasing the lead this amount.
What effect has the action of the link on release and
compression?
Ans. As the cut off is shortened by shifting the position of
the link, these events occur earlier.
1078
Reversing Valve Gaers
What is slip?
Ans. The sliding of the link on the block which occurs during
each stroke.

Thom
LEAD
DECREASE
Wom
FULL GEAR
MID GEAR
A
CROSSED
RODS
W
Figs. 18 and 19.—Diagrams illustrating why crossed rods give decreasing
lead. In shifting the link from full to mid gear the angularity of the rods is so
changed that the valve stem pin P and valve are moved to the right a distance
L, decreasing the lead this amount.
Why does the link slip?
Ans. The center of the block, being pivoted to the valve stem,
moves in a straight line while the ends of the reach rods which
Reversing Valve Gears
1079
guide the link have a circular movement, hence a sidewise
motion is given to the link, causing it to slip or slide on the block.
What is the point of suspension?
Ans. That point where the reach rods are pivoted to the
link.

SLIP WITH END SUSPENSION
END SUSPENSION
SLIP WITH CENTER SUSPENSION
O
O
"!!!


GENTER SUSPENSION
Figs. 20 and 21.-Diagrams illustrating the effect of end and center sus-
pension. When possible, the point of suspension should be at the end of the
link as shown in fig. 20 because the slip is less than with center suspension as
in fig. 21.
1080
Reversing Valve Gears

A
Aldad
B
A
S
B
O
O
Figs. 22 and 23.—The double bar link as used on marine engines. The eccentric
rods are pivoted at A, B and C, D, on the central arc of the link which im-
proves somewhat the steam distribution.
F
2
с
D


L
OH
W
ADJUSTABLE ARM
Fig. 24.-Independent cut off adjustment for link motion; view showing gear
assembled on engine. The reach rods are pivoted to a block which works on
the screw S. By turning this screw at W, the block is moved in the slot and the
link shifted, thus changing the cut off.
Reversing Valve Gears
1081
What is the fixed point?
Ans. The point on the rocker arm at which the reach rods
are pivoted and about which the rods swing; the swing center
of the reach rods.

When is the slip greatest and least?
Ans. Greatest in full gear and least in mid gear.
What is center and end suspension?
Ans. That point where the link is pivoted to the reach rods.
As at the center or the end of the link.
What is the effect of these two points of suspension?
Ans. There is less slip of the block with end suspension than
with center suspension.
Accordingly, slip being very objectionable, end suspension is better
than center suspension.
Name a very objectionable method of suspension.
Ans. Single link offset suspension.
On first class jobs how should the link be suspended?
Ans. By double reach rods end suspension, one rod being
ivoted to each side of the link.
3. Radial Valve Gears
What is a radial valve gear?
Ans. One in which the motion of the valve is taken from
ome point in a vibrating rod, one end of which moves in a
1082
Reversing Valve Gears


■
|
Y
ம்
O
w
math'
...... חוויה.
You
ECCENTRIC
LAP + PORT
OPENING
VALVE ROD
closed curve while a third
point on the rod moves
in a straight line or open
curve.
Ans. It is to obtain
from some reciprocating
or revolving piece of the
VALVE STEM engine, an arrangement
of mechanism, a point in
which shall describe an
oval curve and by alter-
ing the direction of the
axis of this curve, to pro-
vide variable cut off and
reversal.
What is the object
sought in the inven-
tion of radial gears?
HACKWORTH
GEAR
Inside connected type
Forward motion
LINK PIVOT
FULCRUM
INSIDE CONNECTED
ECCENTRIC ROD PIVOT
JODH
F
ECCENTRIC ROD PIVOT
ECCENTRIC ROD
Fig. 25.-Hack
worth inside con
nected valve ged
as constructed fa
a marine engine
view showing th
various parts an
their names.
Reversing Valve Gears
1083
What are the advantages of radial valve gears compared
with link motion?
Ans. 1, More accessible; and 2, better steam distribution.
Name the various radial valve gears.
Ans. 1, Hackworth; 2, Marshall; 3, Bremme; 4, Joy;
5, Walschaert.
What are the essential parts of the Hackworth gear?
Ans. They are as given in detail below.
In fig. 25 the essential parts are: Eccentric, eccentric rod, link, valve
rod, eccentric rod pivot, link pivot, and valve rod pivot, and means
for shifting and securing the link in any position within its arc of
adjustment. As shown, the center of the eccentric is at E, or opposite
the crank. The link consists of a straight slot and guides a reciprocating
block which is pivoted to the end of the eccentric rod at F. The pivot
L, of the link is located in the line X X', which passes through the
center of the shaft perpendicular to the cylinder axis Y Y'. The point
of cut off and direction of rotation of the engine depend upon the
angular position of the link with respect to the axis X X'. The location
of pivot L, and length E F, of the eccentric rod is such that E F = E' L.
When these two distances are equal, F, will coincide with the center
L, of the link when the connecting rod is on either dead center, and
the slotted link may be turned from full gear forward through its
horizontal position to full gear reverse without moving the valve. Hence,
when the lap is the same on both ends of the valve the leads are con-
stant for all positions of the link, and consequently for all cut offs. The
valve is set by adjusting the valve stem for equal lead. The correct
location of the valve rod pivot V, is necessary to secure proper steam
distribution. V, must be so located that when the engine is on the
dead center and the link is in its horizontal position the distance from
V to the horizontal axis XX' =lap+lead.
What is the chief objection to the Hackworth gear?
Ans. The friction and wear of the block and link especially
when the link is in an inclined position.
1084
Reversing Valve Gears

„AURINIO
PIPITORUM
Ilmkk.
VEHI
VU!!FIDE_______Į
PEDREAM
[BEN
MWAN
THE
LEAD
Pắk
PRE-RELEASE
JIONEERI
ems shed den
SIVUNDAMENNESKÐ.
HACKWORTH GEAR
Forward motion
·TATION!
JERISTET
BROWN BOLI
<<DE931801
KA
UMUTRIT 'M■RATE}}:
CUT OFF
COMPRESSION
Figs. 26 to 29.-Hackworth gear at positions of lead, cut off, pre-release and
compression for forward full gear motion.
Reversing Valve Gears
1085

BRUIDON
DI
Im
LIDERA
JJIPRI
#101:
00:
LEAD
ܕܫ ܘܒܫܡܗ
HACKWORTH GEAR
Reverse motion
PRE-RELEASE
*
MEHRSLEM.
| POPJ
CUT OFF
COMPRESSION
Figs. 30 to 33.-Hackworth gear at positions of lead, cut-off; pre-release and
compression for reverse full gear motion.
1086
Reversing Valve Gears

VANDE
III
"'!!!
Milit
....
LAP + LEAD
INE
Lilit
P
RADIUS.
ROD
LEAD
RADIUS
ARM
•
1
www.m. Synt
FORWARD
What was the first modifica-
tion of the Hackworth gear?
Ans. The Marshall gear.
What was the purpose of the
Marshall gear?
Ans. It was introduced to
overcome the chief defect of the
Hackworth gear; that is the
wear and friction of the sliding
block.
MARSHALL
GEAR
www
HEINRI
Forward motion
R
It is virtually the Hackworth
gear with a swinging arm substi-
tuted for the link.
LAP + LEAD
y
—REVERSE:
Fig. 34.-Marshall gear, or first modification of the Hackworth gear.
Reversing Valve Gears
1087
In fig. 34 the eccentric, rod pivot F, located at the end of the rod is
attached to a suspension or radius rod R, the other end of which is
pivoted at P, to a radius arm R', which turns about L, and whose
angular position with respect to the central axis y y', controls the point
of cut off and direction or rotation. In construction, a geared quadrant
is attached to the radius arm to provide means for setting the radius
arm in any position within its arc of adjustment.
The pivot L, is located precisely as in the Hackworth gear.
Since P F, is made equal to P L, the arc described by F, will pass
through L, for all angular positions of the radius arm, and F, will
coincide with L, when the engine is on either dead center. Hence, if
the laps be the same the lead will be constant and equal.
The motion of the valve is the resultant of the two vertical com-
ponents of motion due to the eccentric and radius arms acting at the
ends of the eccentric rod.
CENTER OF
ECCENTRIC
ANGULAR
ADVANCE
90°
RADIUS
ROD

VALVE
ROD
F
a
У
R
RADIUS
ARM
Figs. 35 and 36.-Construction detail of Marshall valve gear showing general
proportion of parts.
1088
Reversing Valve Gears
$6604
I
CUT
OFF
FORWARD
||||||||||||
!!!!!!
VIDUMENT
CUT
OFF
LAP
MARSHALL GEAR
Forward and reverse¸
motions

Fig. 37.-Marshall gear in cut off position for latest cut off; forward gear.
Fig. 38.-Marshall gear in cut off position for latest cut off; reverse gear.
REVERSE
Reversing Valve Gears
1089

4:
UTHMEBUI
#1.11/0
Ul
E
****
VALVE STEM
VALVE ROD
F
BREMME GEAR
Forward motion
K
FULCRUM
The steam distribution of the Mar-
shall gear is not so good as with the
Hackworth gear, due to unequal
travel of the valve on each side of
mid position; this necessitates double
ports at the crank end of the slide
valve in order to get as much port
opening as at the head end.
The eccentricity of eccentric should
be small as possible to reduce inequal-
ity of distribution at the two ends.
Cut off cannot be equalized for all
degrees of expansion, but can be ad-
justed for some given cut off and the
others will be approximately correct.
A slight angular advance may be
given the eccentric with advantage,
sacrificing at the same time equality
of lead for different cut offs. This will
be found to improve the distribution
very much otherwise. The direction
of this angular advance will depend
on the position of the reversing
quadrant and the connections of the
eccentric lever, and must be deter-
mined for the special case.
RADIUS ARM
R
·R'
RADIUS ROD
OUTSIDE CONNECTED
ECCENTRIC ROD PIVOT
ECCENTRIC N
ROD PIVOT
Fig. 39.-Bremme gear, or second modification of the Hackworth gear.
LAP + LEAD
1090
Reversing Valve Gears
The Marshall gear is the simplest of the radial valve gears; its chief
recommendation lies in the small number of working parts and the
excellent distribution of steam but the so called Stephenson link may
be designed to accomplish almost as much. More port opening must
be given to the crank end to get equal steam distribution.

WWWW
IIRMA "II
'IIIIILEM
▬▬▬
BREMME GEAR
Various cut offs; forward motion
Fig. 40.-Bremme gear in cut off position for latest cut off; forward gear.
Fig. 41.-Bremme gear in cut off position for short cut off; forward gear.
A
Reversing Valve Gears
1091
To
How does the Marshall gear compare with the Hackworth
gear otherwise?
Ans. The steam distribution is not so good.

EINE
A
R
Fig. 42.—Joy valve gear, link type. In this gear, as can be seen, no eccentric
is employed, the motion being taken from the connecting rod, thus permitting
more liberal main bearings. The lever A, is pivoted at B, to a block arranged
to slide in the curved link L, the pivot forming the fulcrum of the lever A.
Motion is imparted to the lever A, directly from the connecting rod by means
of the rod C, one end of which is pivoted to the connecting rod, the other
end to the rod D. The vertical motion of the rod C, moves the valve an amount
equal to its lap +lead, while the horizontal motion causes the ports to open
their full opening by moving the fulcrum up and down in the inclined link.
By means of the reversing lever R, the inclination of the link L, can be altered
or reversed, to vary the cut off or reverse the engine.
1092
Reversing Valve Gears
What was the second modification of the Hackworth
gear?
Ans. The Bremme gear.
What is the Bremme gear?
Ans. It is simply an outside connected Hackworth gear fitted
with Marshall's radius rod in place of Hackworth's link, that
is, it is the same as the Marshall gear except that the valve
rod is outside connected or pivoted to the end instead of the
middle of the eccentric rod. See fig. 39.

RADIUS
ROD
Fig. 43.--Joy valve gear, radius rod type. The substituting of a radius rod in
place of the link avoids the objectional friction and wear of the latter.
•
Reversing Valve Gears
1093
Name a leading feature of the Joy valve gear.
Ans. It avoids the use of eccentrics.
What are its characteristics?
Ans. Its motion is superior to that of the ordinary eccentric
in that the ports are opened and closed rapidly with slow valve
movement during expansion and exhaust.
How about the lead and cut off with the Joy valve gear
also the compression?

ECCENTRIC
CRANK
PIN
CONNECTING
ROD
ECCENTRIC
ROD
B
REACH
ROD
LINK
VALVE ROD
STUD
BAR
REVERSE REVERSING
CRANK
SHAFT
Α'
Fig. 44.-Walschaerts valve gear as applied to a locomotive.
VALVE
STEM
Jas
COMBINATION
LEVER
€
Ans. The lead is constant, and the cut off nearly equalized
for all grades of expansion, the compression is less at short
cut off than with link motion.
What are the chief objections to the Joy gear?
Ans. Its great number of parts and joints which are in the
way and subject to wear.
1094
Reversing Valve Gears
Describe the essentials of the Joy gear.
Ans. Motion is obtained from the connecting rod and im-
parted to one end of what corresponds to the eccentric rod in
the previous gears, the other end of which is connected to the
valve rod. See fig. 42.
Name a radial gear used extensively on locomotives.
Ans. The Walschaert gear.
What are the essentials of the Walschaert gear?
Ans. It is a radial gear having a composite motion from a
link or quadrant driven by a return crank or eccentric and a
system of levers actuated by the cross head. See fig. 44.
:
Valve Setting
1095
CHAPTER 54
Valve Setting
What is valve setting?
Ans. The act or process of adjusting the valves of a steam
or other engine so that the various "events" of the stroke as:
admission, cut off, release, compression, etc., occur at their
proper times.
With the ordinary slide valve gear what are the condi-
tions usually encountered?
Ans. The eccentric is retained in position by a set screw; the
length of the valve stem is adjustable. Accordingly, the eccentric
may be in wrong position and the valve stem too long or too
short.
What is missing on assembling the valve gear?
Ans. The dimensions for the valve stem length and eccentric
position, that is angular advance.
In setting the valve what are the three distinct operations
to be performed?
Ans. 1, Locating the engine on the dead centers; 2, finding
the length of the valve stem; 3, determining the correct position
of the eccentric.
These operations are to be performed in the order given.
1096
Valve Setting
What is accomplished by finding the correct length of
the valve stem?
Ans. This equalizes the lead but it may be too much or too
little.
What is accomplished by determining the correct posi-
tion of the eccentric?
Ans. This gives the correct angular advance.
1.
How do you find the dead center?
Ans. The engine is turned in the direction in which it is to run
until the piston has nearly completed the stroke, as shown in
Finding the Dead Center

Fig. 1.-1ram, or instrument used in finding the dead center of an engine. It
corresponds to the bent scriber of a machinist's scribing block.
fig. 2, crank position B. A mark M, to indicate this position,
is made across the guide and cross head. With the straight end
of the tram in the permanent punch mark P, as a center, an
arc C, is described on the side of the fly wheel rim, the surface
first being cleaned of oil, and rubbed with chalk so the mark is
easily seen. The engine is now turned past the dead center until
the mark on the guide again registers with the mark on the
cross head corresponding to crank position A. Arc D, is now
described with the same center P, and an arc passing through
Valve Setting
1097
C and D, is described from the center of the shaft. That portion
of the arc included between C and D, is bisected, giving the
point E. A punch mark is made at this point and the engine
turned in the direction of its future rotation until E, registers
with the bent end of the tram when its other end is in P. In
this position the engine is on the dead center. The other dead
center is found in a similar manner.
Why should the engine always be turned in one direction?
Ans. In order not to introduce any error due to lost motion
in the wrist and crank pins.

M
Fig. 2.-Locating the engine on the dead center. In doing this, as described
in the text, the engine should always be turned in the direction in which it is
to run so as not to introduce any error due to lost motion. The tram marks
should be made permanent with a center punch.
What do you do if the engine has been moved too far?
Ans. In case the engine has been moved too far at any time,
it is not necessary to complete the revolution, but merely to
turn it back beyond the desired point, and then forward again
up to that point in the direction of rotation thus taking up the
lost motion each time in the same direction.
1098
Valve Setting
2. Finding Correct Length of
Valve Stem
How do you adjust the valve stem?
Ans. With engine on dead center, first locate eccentric “by
eye" placing it ahead of its true position rather than behind.
Measure the lead. Put engine on the other dead center and
POSITIVE LEAD
EASILY MEASURED
ZZ
NEGATIVE LEAD
HARD TO MEASURE


ZZ
Figs. 3 and 4.-Positive and negative lead. In setting a valve, the eccentric
is first located "by eye." The figures show why it should be placed ahead of
its correct position rather than behind.
measure lead at that end. They will not be equal (unless
eccentric was set in correct position by accident). The lead may
now be equalized by adjusting the length of the valve stem.
3. Finding the Correct Position of
the Eccentric
Since the eccentric was set by eye how about the lead?
Ans. If the directions were followed the lead is too great. To
correct this the eccentric is turned on the shaft in the direction
in which the engine is to run, until the valve has the desired lead*.
*NOTE.—The lead given to engines varies considerably from a small negative
lead to % inch or more positive lead depending on the type and size of the engine.
Valve Setting
1099

5
FIRST LEAD
SECOND LEAD
7
77
ZZ
Figs. 5 and 6.-Equalizing the lead. By means of a wedge and scriber, the
lead is measured at each end of the cylinder, and the average found as in
fig. 10. In using the wedge the same side must always be placed next the
valve, and held true to avoid error.
Figs. 7 to 9.-Wedges for measuring lead. Prepared from a long piece of wood,
tapered from one-half inch (more or less depending on the size of the engine)
down to "nothing" and cut in several pieces.
engine.
Ans. By the designer of the
Z
7
of lead decided?
How is the proper amount



1100
Valve Setting
In general what does the amount of lead depend upon?
Ans. Upon the speed of rotation and the inertia of the recipro-
cating parts.
Why?
Ans. To provide the amount of cushioning in excess of that
of compression to bring the reciprocating parts to rest at dead
center.
LEAD LINES
→ FIRST
AVERAGE
SECOND

A B C
Fig. 10.-Equalizing the lead. After obtaining the lead lines A and C, as in
Figs. 8 and 9, a line Ba is scribed half way between, which gives the average
lead. The valve stem is then adjusted so that the wedge will enter the port up
to B, thus making the lead the same at each end of the cylinder.
How do you find the correct position of the eccentric on
large engines?
Ans. To avoid the frequent turning of the engine from one
dead center to the other, the necessary adjustments may be
made by equalizing the port opening instead of the lead. The
eccentric is turned until it gives the maximum port opening,
first at one end, and then at the other. These port openings, if
unequal, are equalized by adjusting the length of the valve stem,
Valve Setting
1101
after which, the engine is placed on the dead center, and the
eccentric turned until the valve gives the desired lead.
Setting the Slide Valve Without Removing the Stem
Chest Cover.-If the set screw of the eccentric should work
loose during operation, and the eccentric change its position, it
may be quickly reset without taking off the steam chest cover,
thus saving valuable time in case of a shut down.
EXTREME POSITIONS

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LEAD POSITIONS
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Figs. 11 and 12.-Method of setting the valve without removing the steam
chest cover, when the valve stem does not require adjustment. It consists in
equalizing the two positions L, L', of the valve when the engine is on the
corresponding dead center.
A permanent punch mark is made on the end of the steam chest as
at A, fig. 11, for taking measurements on the valve stem with a tram.
The eccentric is fastened in any position, and the engine turned until
the valve is at one end of its travel. A tram mark B, is made on the
stem to indicate this position, and similarly another mark C, to indi-
cate the other end of the valve travel. The engine is placed on each
dead center and the position of the valve located by the tram. This
gives the two linear advance positions L and L', of the valve, which
in case the eccentric has been incorrectly set, are at unequal distances
L B and L' C, from B and C.
1102
Valve Setting
It remains to adjust the position of the eccentric until LB, is equal
to L'C, as shown in fig. 12. With this condition fulfilled, the valve is
correctly set.
Setting the Slide Valve Without Finding the Dead
Centers. In the case of a very large engine where the opera-

TOO SMALL
A
WAR
'י
B TOO LARGE
1.200
CENTER OF SHAFT
VALVE STEM TOO LONG
CENTER OF
ECCENTRIC
Figs. 13 and 14.-Setting the valve without putting engine on the dead center:
1, equalizing the port opening.
tion of putting the engine on the dead centers would require one
or more assistants, the following method will be found useful.
It consists of:
1. Equalizing the port opening;
2. Finding the angular advance.
Valve Setting
1103
1. Equalizing the Port Opening
What tools are used in equalizing the port opening?

..
M
W
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+1.
HINTE
ACB
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AVERAGE SETTING
.
Mtlulu
Fig. 15.-Method
of finding average
port opening with
inside calipers
and scriber. After
setting calipers for
port opening A,
fig. 13, draw a
line as MS, fig. 15
and place ends of
caliper legs on
this line; mark
these points aa',
with scriber as
shown. Similarly,
set calipers for
port opening B,
fig. 14, and trans-
fer to MS, fig. 15,
measuring from a,
and obtaining
point b. Bisect a'b,
by describing arcs
about a', and b,
S as centers, obtain-
ing the point c, at
foot of a perpen-
dicular through
the intersection of
the arcs, ac, or c,
then is the aver-
age port opening
for which the cali-
pers must be set.
The wedge method
as was used for
equalizing the
lead can be used
to advantage
when the port
opening is less
than the width of
the port.
1104
Valve Setting

DILAK
KESSESIJINI.
L
KERY
F
MERETTILIK
Figs. 16 and 17.-Setting the valve without putting the engine on the dead centers: 1, the port opening
equalized.
Ans. A pair of inside calipers may be used when the port opening exceeds the
width of the port, or if less, a wedge should be used.
Describe the method.
Ans. Loosen the eccentric and turn it until the valve is at one end L, of its travel
and measure the port opening as in fig. 13. Mark this distance for reference with aid
of a scriber as A, in fig. 15.

Valve Setting
1105
Similarly determining the port opening at the other end when the
valve is at that end F, of its travel as in fig. 14, and mark it as B, in
fig. 15. If unequal, set calipers for average port opening C, in fig. 14.
Now rotate eccentric until valve is at either end of its travel and
adjust length of valve stem till valve gives the average port opening
according to average setting C, of calipers.
Compare port opening at other end and if the work has been ac-
curately done, both port openings will be the same, that is, the port
opening has been equalized, as in figs. 16 and 17.
2. Finding the Angular Advance
How do you find the angular advance?
Ans. The several operations to be performed in finding the
angular advance and placing the eccentric in angular advance
position are as follows:
1. Rotating eccentric till valve is in lead position;
2. Finding angular advance;
3. Transferring angular advance to reference mark on shaft;
4. Rotating eccentric to angular advance position.
Performing these operations in the order given, first rotate eccentric
until the valve has the desired lead and locate this position of the eccen-
tric by scribing a line M, on the eccentric and L, on the shaft as in fig. 18.
Now measure diameter of shaft at eccentric with outside calipers
and set dividers to half this length. Wipe all grease from the crank
and chalk same. With one end of the dividers in the lathe center scribe
a circle R, corresponding to the shaft diameter as in fig. 20.
Next take a small string, or preferably strong flax thread and make
a loop at one end and place it around the crank pin; pull very taut,
holding it so that it intersects the shaft lathe center, and scribe the
point F, where it cuts the shaft circle. The thread then represents the
center line of the crank.
1106
Valve Setting
Now by means of a level, scribe a horizontal line passing through
the shaft center and cutting the shaft circle at L Evidently the angle
LAF, is the angular advance, which can be easily transferred to the
eccentric by a pair of dividers.
Set the dividers as in fig. 18 to measure the arc M S, then place one
leg of the dividers on M, in fig. 18 and lay off M S, in the direction
of rotation.
Turn the eccentric till its reference mark L, coincides with S, as in
fig. 19 and secure eccentric in this position, when, if all the operations
have been properly performed the setting will be found correct.

QUINT
M
*****
*******
Figs. 18 and 19
ANGULAR ADVANCE
MS (FIG.812) LF(FIG. 813)
ECCENTRIC TURNED TO CORRECT
ANGULAR ADVANCE SETTING
VALVE IN LEAD POSITION
C
Fig. 20 is on page 1107.
N
Figs. 18 to 20.-Setting the valve
without putting the engine on the
dead center: 2, finding the an-
gular advance. Fig. 18 shows
eccentric turned to position cor-
responding to lead position of
valve, indicated by marks ML,
on shaft and eccentric. In fig. 19
2
URELIA
Valve Setting
1107
Setting an Inside
Admission Piston Valve
How do you set an inside admission piston valve?
Ans. The valve cannot be set by direct lead measurements
as with the slide valve; use is therefore made of the exhaust
edge of the valve as a basis for measurements.
VILIA
What are the necessary operations in setting an inside
admission valve?
Fig. 20.
SETTING DIVIDERS TO
TRANSFER ANGULAR ADVANCE LF

****
ANGULAR ADVANCE-
SHAFT CIRCLE
LEVEL
A
R
Figs. 18 to 20.— Tzxt continued.
the shaft circle, crank center line
and horizontal line are located,
giving arc LF, the angular ad-
vance which is transferred to shaft
by dividers giving point S, in fig.
18, to which point the reference
line L, on eccentric must be
turned as in fig. 19.
1108
Valve Setting

سلسلسال
M
2
E
Mahal
V
B
#
-S
E'
E→
A
15
Figs. 21 to 23.-Setting an inside admission piston valve. The two extreme
positions are measured as in fig. 21, and the travel equalized by adjusting
the valve stem. The engine, is placed on each dead center, and measurements
Valve Setting
1109
******
1,
Ans. 1. The two extreme positions of the valve must be
equally distant on either side of the neutral position. 2. With
equal lead, the linear advance must be the same for each end
of the cylinder.
EXHAUST EDGE

STEAM
EDGE
1000
City --
M-
S
Fig. 24.-Method of measuring the location of the ports. A strip of metal is
soldered on the brass end of the scale as shown, being placed at the side to
measure the steam edge M, and over the end, for the exhaust edge S.
DEEM VAN 189 AM HALKS
Applying the first principle, the valve is adjusted so that the valve
travels an equal distance each side of its neutral position.
Applying the second principle, the engine is placed on each dead
center, and the distances of the exhaust edges of the valve from the
ends of the cylinder measured. These distances must be equalized.
Figs. 21 to 23.-Text continued.
taken as in figs. 22 and 23. The position of the eccentric is then adjusted until
E, fig. 22, equals E' fig. 23. If M and S, be unequal due allowance should
be made.
1110
Valve Setting

• C
VALVE IN LEAD POSITION
DIRECTION OF ECCENTRIC
ADJUSTMENT
LIVE STEAM THROUGH PET COCK
INDICATING LEAD POSITION OF VALVE
Man, nginkadul Kala
||.|
CRANK AT DEAD
CENTER
ANGULAR
ADVANCE/
ECCENTRIC
LOOSE ON
SHAFT
"10/
Fig. 25.-Emergency method of setting the valve by placing engine on center, turning eccentric, and observing
open cylinder cock. During the operation the throttle valve should be "just cracked.
}}
Valve Setting
1111
Emergency Rule for
Setting the Slide Valve
Give an emergency rule for setting the slide valve in
case the eccentric should slip on the shaft.
H EX.
H
Ans. The engine is placed on the dead center and the eccentric
turned a little behind its correct position. With the right cylinder
drain cock open, a small amount of steam is admitted and the
PISTON VALVE

EX.
с

C
END OF CYLINDER
1/2 TRAVEL
BUSHING
Figs, 26 and 27.-Inside admission piston valve battens. They are especially
useful to check the valve setting. The ends of the cylinder should be indicated
on the seat battens in addition to the bushings.
eccentric turned forward until steam issues from the cylinder
cock, as in fig. 25, which indicates that the valve has lead.
The eccentric is fastened in this position and the engine turned over
to the other dead center. If steam escape from the cock at this end,
the valve is in position for service until an opportunity occurs to open
the steam chest in order to set the valve with more precision.
Setting the Riding Cut-Off Gear
There are two types of riding cut off gears encountered in
valve setting. They are:
1112
Valve Setting
1. Riding cut off with movable eccentric.
2. Riding cut off with fixed eccentric.
1. Riding cut off; movable eccentric.
How is the main valve set?
Ans. In the same manner as the ordinary slide valve.
STEAM PASSAGES

S
S
Fig. 28.-Showing similarity between the main valve of a riding cut off gear,
and the ordinary slide valve. The main valve is simply a plain D valve, having
steam passages S, S' at its ends, and planed on its back to form a seat for the
cut off valve.
What should be noted about the main valve?
Ans. To avoid confusion, it suffices to remember that the
main valve is nothing more than an ordinary D valve, having
steam passages at its ends, and planed on its back to form a
seat for the cut-off valve, as in fig. 28.
What should be ignored in setting the main valve?
Ans. The outer end walls are to be ignored.
*
Valve Setting
1113

NEGATIVE
LAP
RIDING GUT OFF VALVE
MAIN VALVE
G
P'
D
A'
M' B'
M B
Z
Z
Fig. 29.-The riding cut off gear with both valves in neutral position. Tram marks M, M', are made on the stems
to locate these positions, also A, B, and A', B', to locate the extreme positions. The same tram should be
used for both valve stems.
The relation between the main valve and an ordinary D, valve is shown in fig. 28. The latter
being illustrated in solid black section; the main valve has in addition to this, the portions shown
at each end which contain the steam passages S and S'.
What is the first operation?
1114
Valve Setting
Ans. The engine is now turned in the direction in which it
is to run, until this valve is in its neutral position.
What is the reason for putting the main valve in its
neutral position?
Ans. It is to facilitate this adjustment, as the necessary
measurements are more conveniently made with respect to the
main valve than to the seat.
How do you put the valve in the neutral position?
Ans. The engine is turned over until the main valve comes
in the extreme positions A and B, as shown in fig. 29, and a
reference mark for each, made on the valve stem with a tram,
having one end in a convenient fixed center P. The distance
A B, is bisected, giving the point M, the three points being
permanently located with a center punch and care being taken
that the points are in a straight line parallel to the stem. The
valve is now placed in its neutral position, by turning the en-
gine in the direction of its rotation until the point M, registers
with the end of the tram as shown in the figure.
What is the next step?
Ans. The next step is to equalize the travel of the riding
valve, that is, to adjust the riding valve stem or eccentric rod
to the proper length so that the valve will travel an equal
distance each side of its neutral position.
What precaution should be taken to avoid error?
Ans. It should be ascertained that the steam ports of the
main valve are equidistant from the ends; if not, measurements
E and F, fig. 30, should be taken with respect to the steam
edges of the cut-off valve, lines being lightly scribed on the back
of the main valve to indicate the extreme positions.
Valve Setting
1115
Describe how the travel of the riding valve is equalized?
Ans. With the main valve in its neutral position, the movable
eccentric is loosened on the shaft, and turned in the direction in
which the engine is to run until the cut-off valve is brought into
its extreme positions A' and B', fig. 30. The distance from the
steam edge of the riding valve to the end of the main valve is
Cabibullahutus
EXTREME POSITIONS OF CUT OFF VALVE
A'
B'
*E
Fig. 30.-Equalizing the travel of the riding valve. With the main valve in
neutral position, and cut off eccentric loosened, the distances E and F, are
measured for the two extreme positions and the valve stem adjusted until
these distances become equal.
measured for the two positions. If the valve stem be too long
or too short these distances will be unequal; the valve stem or
eccentric rod, in this case, should be adjusted until these dis-
tances E and F, are equal as shown in the figure. Having
equalized the travel of the valve, tram marks A', B', M',
་

1116
Valve Setting
indicating respectively the extreme and neutral positions, should
be made as shown in fig. 29, on the cut-off valve stem with the
tram center at P', using the same tram as was used for the
main valve stem.
What remains to be done to complete the setting?
Ans. The position of the movable eccentric which will give
the desired cut off must be found.
CUT OFF VALVE CLOSING STEAM
PASSAGE FOR 1/2 CUT OFF

2
Fig. 31.-Riding valve in cut off position. To locate eccentric for any desired
cut off, turn engine over till piston is at the desired point of cut off, then turn
riding eccentric in the direction of motion till riding valve is in cut off position
as shown.
How is this done?
Ans. If the valve gear is to cut off at, say one-half stroke.
the engine is turned in the direction in which it is to run to
this point of the stroke, and the movable eccentric turned in
the same direction until the cut-off valve has just closed the
steam passage through the main valve as shown in fig. 31, the
eccentric is now fastened in position.
When the riding cut-off valve is operated by an automatic governor, as
in many stationary engines, this last step is, of course, omitted.
Valve Setting
1117
When the engine is provided with a governor, the travel of the cut-off
valve may in some cases be more conveniently equalized, by locating
the center of the valve seat with a line scribed on the side or flange of
the steam chest, and equalizing the travel of the cut-off valve with
respect to this line instead of the main valve. By this method it is not
necessary to retain the main valve in its neutral position while adjusting
the cut-off valve; hence the loose eccentric need not be disconnected
from the governor in making this adjustment.
RIGHT
THREAD
A-
CUT OFF BLOCKS
M

S LEFT
THREAD
-B
NEGATIVE LAP
Fig. 32.-The riding cut off with fixed eccentric, showing cut off blocks M,
S, screwed together when setting the valves. The cut off is latest when the
blocks are together, depending on the negative lap. After setting the valves,
the blocks should be fully extended for earliest cut off to see if there be any
reopening after cut off and before the main valve has closed.
2. Riding Cut Off; Fixed Eccentric.
This type of riding cut off is set in much the same way as
the preceding form. In making the adjustments, the important
principle upon which the gear is based should be understood,
and kept in mind.
What is this principle?
1118
Valve Setting
Ans. The angular advance being fixed, the cut off is varied by
changing the lap.
How is the main valve set?
Ans. In the same manner as the ordinary slide valve.
How is the riding valve set?
Ans. The riding blocks M, S, are first screwed closely to-
gether as shown in fig. 32, this being their position for latest
cut off.
The travel of the riding valve is now equalized by the method just de-
scribed, and the riding eccentric located in the position best suited to the
conditions under which the engine is to be operated.
How is the riding eccentric set for a marine or reversing
engine?
Ans. The riding eccentric is set opposite the crank, that is,
at 90° angular advance, since the motion of the cut-off valve
is then correct for both forward and reverse motion; in this
position an equivalent motion of the eccentric may be imparted
to the valve stem by the cross head through a lever, thus
dispensing with the eccentric.
The angular advance of the riding eccentric on stationary engines is
usually a little less than 90°. The effect of reducing the angular ad-
vance is to require a smaller movement for a given change of cut off.
The riding eccentric should be so located that it will give the most
rapid closure of the steam ports for the cut off mostly used.
What check up should now be made?
Ans. The engine is now turned over to see if there be any
reopening of the riding valve after it has cut off and before the
main valve has cut off. Similarly it should be observed that
there is no reopening for earliest cut off.
Valve Setting
1119
What should be done if the cut-off valve re-open before
cut off of the main valve?
Ans. This must be corrected by altering the position of the
riding eccentric.
Setting a Link Motion
Adjustments of the link gear should be such that the steam
distribution will be favorable to smooth running and economy
for the particular degree of expansion at which the engine is
generally run. For instance, engines which work in full gear
require a setting different from those which cut off short; the
final adjustments therefore should be made with respect to
obtaining the best results for the gear position mostly used. In
general, setting a link motion comprises the following operations:
1. Equalizing the travel;
2. Adjusting the eccentric rods to uniform length;
3. Finding the correct positions of the eccentrics;
4. Making final adjustments for best steam distribution in
the gear position mostly used.
1. Equalizing the Travel.
How do you equalize the travel?
Ans. With the engine on the dead center, both eccentrics
are turned on the shaft to the extreme position and the link
placed in mid-gear as shown in figs. 33 and 34. If the length of
the valve stem be correct, the valve should be in its extreme
1120
Valve Setting
position, that is, the port opening A, for this dead center should
be the same as port opening B, for the opposite center.
In case the port openings be unequal, the travel of the valve must
be equalized by adjusting the length of the valve stem, or the eccentric
rods, whichever be the more convenient.
2. Adjusting the Eccentric Rods to Uniform Length.—
Both eccentric rods should be of the same length and probably
will be when not made adjustable. If both rods be of the same
A
B
T

A MUST EQUAL B
EXTREME POSITION
MID-GEAR
Figs. 33 and 34.-Setting the_link_motion. 1. Equalizing the travel by
adjusting the valve stem. The eccentrics must be placed in extreme posi-
tion and link in mid-gear.
length, the position of the valve is unchanged for either full
gear position when the engine is on the dead center and the
eccentrics are in the extreme position.
How do you adjust the eccentric rods to uniform length?
Ans. The engine is placed on the dead center, with the link
in full gear and the eccentrics in the extreme position as shown
in fig. 35. The position of the valve or stem is marked in such
a way that any movement in either direction can be measured.
If both rods be of the same length, the mark on the valve stem
will return to its original position when the link is shifted to
Valve Setting
1121
its opposite or reverse full gear position; if the mark be dis-
placed in either direction the reverse rod should be adjusted
until the line returns to its original position. It is rarely neces-
sary to make this adjustment, except when a gear has been
completely dismantled.
3. Finding the Correct Positions for the Eccentric.

FORWARD FULL GEAR
Fig. 35.-Setting the link motion: 2. Adjusting the eccentric rods to uni-
form length. The link is placed in forward full gear position. If rods be equal
position of valve should be the same when link is shifted to reverse full gear.
NEUTRAL POSITION
ZERO ANGULAR ADVANCE


SADA
first step:
Fig. 36.-Setting the link motion: 3. Locating the eccentrics
Both eccentrics are placed at zero angular advance, that is at right angles to
the crank, bringing valve into neutral position.
How do you find the correct positions?
Ans. With the engine on either center, the link is placed in
the forward full gear position, and the eccentrics turned from
the extreme position until they are at right angles with the
crank, that is, where the angular advance equals zero as shown
1122
Valve Setting
in fig. 36. The forward eccentric is now turned, in the direction
of forward rotation, until the valve shows the desired lead as
in fig. 37.
Similarly, the link is shifted to the reverse full gear position, fig. 38,
and the reverse eccentric turned, in the direction of reverse rotation;
until the proper lead is obtained as shown in fig. 39. Each eccentric
is fastened after locating its position, and the results tested by trying
the leads for the opposite centers, which completes the setting for
engines operating in full gear.
LEAD POSITION
#
FORWARD ECC. ADVANCED


FORWARD FULL GEAR
Fig. 37.-Setting the link motion: 4. Locating the eccentrics — second step:
With link in forward full gear, the forward eccentric is advanced until valve
shows proper lead, bringing valve into its forward linear advance position.

NEUTRAL
POSITION,

REVERSE FULL GEAR
Fig. 38.-Setting the link motion: 5. Locating the eccentrics — third step:
The link is shifted to reverse full gear position, bringing valve back to its
neutral position.
4. Final Adjustments.-For engines which use the link
motion as a variable expansion gear, the best results are ob-
tained when the valve is set to give the proper lead for the
"runnung cut off."
This applies especially to locomotives and engines which usually run
with a considerable degree of expansion. Since the lead increases from
Valve Setting
1123
full to mid-gear, it is obvious that if it be correct in full gear, it will
be too great when hooked up for short cut off working.
How is the lead corrected?
Ans. The lead may be corrected for the running cut off, by
placing the link in the running position, and setting back the
forward or reverse eccentric, or both, in equal or unequal
amounts until the desired lead is obtained.
The particular method of correcting the lead depends on the condi-
tions of service. For engines which run mostly in forward gear, as
express passenger engines, it is of little importance if both eccentrics
have the same angular advance, however, for suburban tank locomo-
tives, or those running considerable distances in each gear both eccen-
trics should have the same angular advance.

LEAD POSITION

REVERSE
FULL GEAR
REVERSE ECC. ADVANCED
Fig. 39.-Setting the link motion: 6. Locating the eccentrics — fourth step:
The reverse eccentric is advanced until the valve shows the proper lead; this
moves the valve to its reverse linear advance position which completes the
setting except when final adjustments are made to adopt the link motion to
special running conditions.
Setting Pump Valve Gears
1. Simplex pumps.-There are two general classes of sim-
plex pumps as those having:
1. A separate auxiliary valve, and
2. Auxiliary valve and auxiliary piston combined.
1124
Valve Setting
In pumps of the first mentioned type, the auxiliary valves
usually have stems or tappets which project into the cylinder
at the ends and are moved by contact with the main piston
as it nears the end of the stroke.
Examples of the two general classes of simplex pumps are shown on
pages 387 and 389. Pumps of the first mentioned class require no
valve setting.
How do you set the valves of the simplex pump in which
the auxiliary valve and auxiliary piston are combined?
Ans. To set the valve piston, push the main pistons to the
end of the stroke until the inner edge of the port and the piston
coincide, then loosen the side lever, turn the cam C, until the
valve piston uncovers the auxiliary steam port E, (see page
389), leading to the same end of the steam chest occupied by
the main piston.
What should be done after setting?
Ans. Secure the cam and then connect the side lever to the
connecting rod. The side lever and cam occupy correct relative
positions, therefore, the lever should be secured to the cam
shaft while in this position. The stroke may be regulated by
raising or lowering the end of the connecting rod in the slotted
end of the slide lever. Raising the connecting rod shortens the
stroke and lowering it lengthens the stroke. When making the
foregoing adjustments it is well to have the connecting rod at
or near the bottom of the slot as shown in fig. 37, page 389.
2. Duplex Pumps.-The valve gear of duplex pumps has
been explained at considerable length in Chapter 23 on Boiler
Feed Pumps. It remains only to give instructions for setting
the valves.
Valve Setting
1125

1000
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a0000
COCOOOOO!
AII
$30000
X
Y
P
M
N
Fig. 40.-Valve and valve gear of duplex pump, showing rocker in its two extreme positions M and N, and
the corresponding position of the valve stem end X and Y.
How do you set the valves of a duplex pump?
Ans. Place a small stick or batten against the end of the valve chest, and mark the
center of the pin P on the same, as indicated in fig. 40. Then move the piston, of the
same side, to the other end of the stroke, and again mark the position of the pin P, on
the same stick, as indicated by the dotted lines. The two marks M, and N, thus ob-
tained, denote the extreme travel of the pin P.
1126
Valve Setting
What is the next step?
Ans. It will now be necessary to obtain the marks X and Y
on the same stick, which indicate the positions of the pin L,

D
Exx
M.
X Y
23
E
XK
不
​X Y
IV
XEY
E
xk
Y
D
**
MN
*
E

λ
D

*
MN

*
MN
* *
D


X
Figs. 41 to 46.-Paper template and batten with center marks as used in ad-
justing the valves of a duplex pump as fully explained in the accompanying
text.
Valve Setting
1127
when the valve has moved from one full port opening to the
other
95
Now take a strip of stiff paper, and mark upon it the exact distance
between the center of the holes in the valve connecting link, as D and
E, fig. 41. Try the distance between the marks D and E, on the strip
of paper, against the marks X and M, and Y and N, and if they should
coincide as in fig. 42, the valve is correctly adjusted, and the links
should be put into their places, and the valve chest cover replaced.
If, however, the marks should fall as in fig. 43 or fig. 44, it is evident
that the valve stem is either too short as in fig. 43, or too long as in
fig. 44, and it must be either lengthened an amount equal to the dis-
tance E Y, fig. 43, or shortened an amount equal to the distance E Y,
in fig. 44.
What do figs. 45 and 46 show?
Ans. They show other positions in which the marks on the
stick and the strip of paper may fall. In both cases, the travel
of the valve between the two inside edges of the steam ports
evidently does not coincide with the travel of the pin P, fig. 40,
indicating that there is either too much lost motion between the
valve stem and the valve, as in fig. 45, or not sufficient, as in
fig. 46.
What should be done before attempting to alter the lost
motion?
Ans. Reinove the valve entirely and see whether the distance
between the steam and exhaust edges of the valve, as F and G,
and H and I, page 397, correspond with the distance between the
working edges of the ports K and O, and Q and R, respectively.
If these distances agree with each other, and the marks representing
the valve and pin travel fall as in fig. 45, it indicates that the valve
*NOTE. -When sliding the valve from one full port to the other, care should
be taken to do this by moving the valve stem, to obtain the full effect of the lost
motion between the nut and the lugs on the back of the valve.
―――
1128
Valve Setting
has not sufficient motion to fully open the ports, hence less lost motion
has to be given. Fig. 46 shows the reverse of this condition.
Should the distance, between the edges F and G, or H and I, be
found shorter than the distance between their respective port edges,
an amount equal to one-half the difference between E' E and X Y, fig.
46, the steam edge of the valve will over travel the inner edge of the
steam port, when the valve is connected up, but the exhaust port would
have just full opening, indicating that there is some exhaust lap, and
if the pump be found to run smooth, it is advisable not to tamper with
the adjustment of the lost motion.
с

A B
CAB
Fig. 47.-Location of cross head centers on duplex pumps.
If it be necessary to increase the lost motion between
valve and stem, on a pump provided with such an adjust-
ment as in fig. 40 how can it be done?
Ans. Decrease the width of the nut by filing or machining
in a shaper.
To decrease the lost motion, either a new nut must be provided, or
sheet metal washers of the required thickness may be cut, and placed on
the valve stem between the nut and the lugs on the back of the valve.
The method of valve setting just described is only suitable for small
pumps; the larger ones generally being provided with an adjustment
as in figs. 48 or 49. The arrangement shown in fig. 40 is very simple,
and permits accurate adjustment, but in order to do this, it is necessary
to remove the valve chest cover.
Valve Setting
1129
The type shown in fig. 48, is mostly used on large and more expensive
pumps, and permits alterations in the adjustment being made while
the pump is running.
In fig. 49, the lost motion can not be altered, without taking off or
adding to the ends of the block S, but the sleeve nut in the connecting
link is a good device for altering the length of the valve stem.
It is seldom the case that the amount of lost motion has to be altered,
and unless the operator be thoroughly familiar with the details and
design of the pump, he should not undertake such alterations, as the
designer knows best what the requirements are.

++
LOST MOTION
00000
LOST MOTION
LOST MOTION
ADJUSTMENT
ос
+:
Fig. 48.-Rocker arm and connections as usually designed for large pumps,
with lost motion adjustment. In this arrangement the lost motion can be adjusted
while the pump is in operation.
Short Rules for Setting the Valves of a Duplex Pump.
-It may be helpful in acquiring a knowledge of how to set
the valves to consider simply the essential operations without
the various details or methods of performing them as given in
the foregoing instructions: They may be briefly expressed in
the form of rules as follows:
1130
Valve Setting
1. Locate the steam piston in the center of the cylinder;
This is accomplished by pushing the piston to one end of its stroke
against the cylinder head and marking the rod with a scriber at the
face of the stuffing box, and then bringing the piston in contact with
the opposite head.
2. Divide exactly the length of this contact stroke;
Shove the piston back to this half mark; which brings the piston
directly in the center of the steam cylinder;
3. Perform the same operation with the other side;

N
M
S
Fig. 49.-Lost motion arrangement consisting of yoke M, and block S, pivoted
at the rocker end. In this design the lost motion cannot be changed without
altering the length of the block S, but the length of the valve stem can be
adjusted by means of the sleeve nut N.
4. Place the slide valves in their central position;
5. Pass each valve stem through the stuffing box and gland;
The operation of placing the pistons in the center of their cylinders
brings the levers and rock shafts in a vertical position;
6. Screw the valve stem through the nuts;
The stem is screwed until the hole in the eye of the valve stem head
comes in a line with the hole in the links, connecting the rocker shaft.
7. Put the pins in their places;
8. Adjust the nuts on both sides of the lugs.
Leave about one-eighth to one-fourth inch lost motion on each side.
Hoists
1131
CHAPTER 55
Hoists
Steam, Gas, Diesel, Air
What is a hoisting engine?
Ans. A combination of engine boiler and drum or drums
used to hoist materials.
Describe a simple hoist.
Ans. It consists of one or two slide valve engines and a ver-
tical boiler mounted on one base plate. The engines (two cylin-
der type) are connected to the ends of the shaft with crank
pins, at 90°, hence, no dead center. A friction brake is provided
so that the drum may be prevented turning when desired. The
power of the engine is applied in hoisting by means of a cable
fastened to the drum.
The Boiler
What kind of boiler is used for steam hoists?
Ans. A vertical tubular boiler usually having through tubes.
How should the boiler be proportioned and why?

1132
Hoists
04
97
93
96
95
804
88 Throttle Lever
89 Boiler Braces
00
52
76
$4
75
90 Throttle Extension Rod
90a Throttle Extension Rod Coupling
91 Throttle Valve
300
76/36
68
74
99
98
97
$9
88
00
35
68
75 74
88
57
52
53 54 84
40
92 Lubricator, Sight Feed
93 Exhaust Pipe
81
94 Steam Pipe
95 Three-way Exhaust Cock
71
.66
67
61
67
02
Numbers 88 to 100 are not shown on any other pa
page
65
73
85
81
71
Fig. 1.-Double cylinder, double friction drum steam hoisting engine, with boiler
and fixtures complete. Names of the numbered parts are given in accompanying
lists.
72
65
61
42
Bond to
96 Injector
97 Glass Water Gauge
98 Steam Gauge
99 Boiler Dome
100 Smoke Stack
Hoists
1133
OF ENGINE
Ans. There should be ample heating surface and grate area
for the engine so that the work may be done with easy firing.
Why easy firing?
REAR
MAGTEODORJUNIO:
THIRD
LEFT SIDE OF ENGINE

OI

RIGHT SIDE OF ENGINE
Fig. 2.-Plan view of steam hoist showing rear and front of engine, right hand
and left hand sides of engine. Correct use of these terms is important in
ordinary parts.
MARAUD
OF ENGINE
FIRMAI
**་དོWT
FRONT

goo
HOP
Taifa
Fig. 3.-Steam hoist boiler, hood, grate and lugs. Some proportions are engine;
boiler diameter 64 x 8; 36, 7 x 10; 40. 8½ x 10; 42. 10 × 12; 54.
1000

1134
Hoists
33%
OR
M
7 Steam Chest Gland
% Piston
Piston Ring
10 Piston Rod
28
30
33
32
17 18 21
1 Back Cylinder Head, Right Hand
1a Back Cylinder Head, Left Hand
2 Cylinder and Steam Chest, Right Hand
2 Cylinder and Steam Chest, Left Hand
3 Cylinder Jacket
4 Front Cylinder Head, Right Hand
4 Front Cylinder Head, Left Hand
5 Cylinder Gland
6 Steam Chest Cover
28
30
11
12
13 Slide Valve
Piston Rod Nut (on piston end 22
of rod; it is not shown)
23
Piston Rod Jam Nut
24
25
26
27
28
14 Slide Valve Clamps
14a Slide Valve Nuts.
144
115 Valve Stem
16 Valve Stem Jaw
17 Valve Stem Jaw Pin
14
18 Cross Head, Right Hand
18a Cross Head, Left Hand
19 Cross Head Cap
20 Cross Head Gib (Brass)
21 Cross Head Pin
E
19
29
30
31
32
bluorla
14A
29
34
Figs. 4 to 10.-Details of cylinder and reciprocating parts of the steam hoist
shown in fig. 1. See accompanying parts lists.
33
18
21
Slide Bar
Slide Bar Bracket
45
16
21
23
31
27.331/%
39000
NOTE-Parts with numbers in brackets are usually furnished as one piece.
O
25
Connecting Rod
Connecting Rod Box (Brass) Crank End
Connecting Rod Box (Brass) Cross Head End
Connecting Rod Key, Crank End
Connecting Rod Key, Cross Head End
Connecting Rod Gib, Crank End
Connecting Rod Gib, Cross Head End
Connecting Rod Strap, Crank End
Connecting Rod Strap, Cross Head End
Connecting Rod Set Screws
33
334 Connecting Rod Bolt, Crank End
33% Connecting Rod Bolt, Cross Head End
Hoists
1135
Ans. So that the engineer may operate the engine without too
frequent interruptions.
What method is used for feeding the boiler?
Ans. An injector.
In some cases there is a feed pump operated by the engine. This is
a good method of boiler feed especially when a feed water heater is used.
Describe the exhaust piping.
Ans. The exhaust pipe terminates in a two way cock with
one branch connected to the smoke stack and the other open
to the atmosphere.
What is the object of this arrangement?
Ans. Steam from the engine can: 1, be exhausted directly to
the atmosphere; or 2, through the stack. Exhausting through
the stack induces a strong draught.
As an auxiliary for accelerating the combustion usually an inde-
pendent jet blower is provided.
What should be noted about the two way cock in the
exhaust pipe and why?
Ans. It should give full opening and if not, a larger size cock
should be installed as otherwise a waste of power will take
place by choking the exhaust, that is, increasing the back
pressure on the piston.
The Engine
What kind of engine or engines are used?
Ans. Ordinary single or two cylinder slide valve engines.
For light service a single cylinder engine is sufficient.
ܕ

1136
Hoists
17
36
65
34 Crank Shaft
35 Crank Wheel
36 Crank Pin
37 Pinion
3% Eccentrics
35
61
40
23
38
FD
41
39 A
37
60
339 Eccentric Strap
139 Eccentric Strap
40 Eccentric Rod
59 A
59 59A
48A
34
48-
58
46
45
39
-38
47
38-
62.
63
23
64
56
41 Eccentric Strap Bolts
42 Eccentric Rod Jaw (for Link Jaw)
43 Eccentric Rod Nuts (not shown)
NOTE-Parts with numbers in brakets are usually furnished as one piece.
46
Figs. 11 to 14.-Friction drum parts, pedestal, eccentric, crank shaft, etc., of
the steam hoist shown in fig. 1.
47
35
44. Side Stand (right)
45 Side Stand (left)
46 Side Stand Caps (for drum shaft)
47 Crank Shaft Caps
48 Valve Stem Bracket
48a Valve Stem Bracket (for link motion)

Hoists
1137
What is the objection to the single cylinder engine?
Ans. Dead centers.hata
The two cylinder engine with crank pins at 90° avoid dead centers,
in other words is self starting.
Number
Stamped
Here
How are the cylinders anchored?
Ans. They are attached by bolts to the base plate-not to
the boiler.
4781
Number Stamped Here
Plate 1981
Fig. 15.-Usual places for shop numbers on steam hoists. The shop number will
be found stamped on the top edge of the back cylinder heads. These numbers.
may be covered by paint or dirt, but can be found by scraping the surface clean.
doug
Power Transmission
What kind of drive is used for light loads?
Ans. For light loads and high speeds, as on coal wharves,
engines are sometimes made with a direct drive, that is, the
crank is on the same shaft as the drum.
1138
Hoists
What is the arrangement for heavy loads and why?
Ans. For this service it is desirable to place the drum on a
separate shaft and reduce its speed by means of spur gearing,
thus allowing the engine to make several revolutions to one of
the drum.
What is the object of gearing?
Ans. To avoid large cylinders.

H
ا ...
-
EXPLETE
NETTE 19006
D
D
KARTONSTAD XILIUMEDATE
Drums
Η
Fig. 16.-Sectional view of loose drum. The parts are: A, shaft; B, friction blocks;
C, friction flange; D, drum; E and F, friction rings; H, winch head or spool;
J, J, bearings, K, gear wheel; P, thrust screw; S, drum flange; T, ratchet teeth.
Name two types of drum.
Ans. The fixed and the loose drum.
KOTIMAA
TRIIN:
Minion
What is the application of the fixed drum?
Ans. It is used on the simpler, machines designed for that
class of work which requires only the operations of lifting or
lowering or where only single loads have to be handled.

Hoists
1139
70
+41
87
86
85
69-A
84
$2 Friction Lever
PROTO T
50 Priction Nut Stud Bolt (short)
50a Friction Nut Stud Bolt (long)
51
Friction Lever Stop
53 Friction Lever Clamp
54 Friction Screw
55 Friction Screw Point
69
49 Friction Nut (and Oil Box Combined) 61
56 Friction Pin
56a Friction Pin Felt Washer
57 Friction Drum
57a Friction Drum Bushing979
58 Friction Drum Shaft
52
59 Friction Drum Spring
19a Friction Drum Shaft Washers
60 Friction Woods
77
49
68
372
53
50
84
56
54
60
56A
66 Ratchet Ring
67 Friction Drum Oil Pipes
70
Spur Gear
eval c
62 Cross Key Collar
63 Cross Key
64 Drum Shaft Screw Collarbanely
65 Winch Head
68 Brake Shaft
69 Brake Cam, Differential Type
692 Brake Cam, Single Acting Type
70 Brake Shaft Collars
74
71 Brake Band
72 Brake Blocks
TA
73 Brake Band Support (complete)
w WSTOR
8767
Figs. 17 to 26.-Additional details of friction drum, operating gear, bed plate
and ash pan of the steam hoist shown in fig. 1.
de elt no imuth of to renom berbag
A
state
for
which
drum
55
id 90
73
49
www
יד.
ها
150 82
$4.
76
gila & van
74 Foot Brake Lever
75 Foot Brake Lever Clamp
76 Foot Brake Counterweight
77
state
for
71 Pawl Shaft which
79 Pawl Counterweight
drum
30 Pawl Bracket (not shown),
81 Guard Band for Gearing
82 Bed Plate
82a Bed Plate for Mining Engine
83 Ash Pan
34 Pillow Block (right)
85 Pillow Block Cap (right)
86 Pillow Block (left)
87 Pillow Block Cap (left)
1140
Hoists
What is the application of the loose drum?
Ans. This is the type mostly used and is so constructed that
it may be thrown in and out of engagement while the engine is
in motion, by the action of friction rings.
How is the drum thrown in action?

DRUM
A
BEARING
STEEL
COLLAR
COLLAR KEY
SLOT
F
p'
THRUST PIN
THRUST SCREW
STEEL
FRICTION LEVER
LEFT HAND
THREAD
THRUST COLLAR
T COLLAR
Fig. 27.-Sectional view of friction control on loose drum. When the friction lever
is turned counter-clockwise, the left hand friction screw pushes the thrust pin to
the left. The pin in turn pushes the collar key, collar, and drum in the same
direction causing the latter to engage with the friction blocks.
Ans. By a slight endwise movement of the drum on its shaft
produced by turning a lever attached to a screw whose end is
in contact with a hardened thrust pin.
Describe the action of the thrust pin.
Ans. When the engineer turns the friction lever toward him
(counter clockwise) the thrust screw which has a left hand
Hoists
1141
thread, pushes the thrust pin against a collar key, which works
in a slot cut through the shaft. The collar key, together with
the collar, is in turn pushed against the drum, forcing it into
contact with friction blocks to prevent any rotation on the shaft.
Why easy firing?
Ans. There should be ample heating surface and grate area
for the engine so that the work may be done with easy firing.

Halbâ
Hi
Fig. 28.-Brake and friction levers with safety attachment. When the friction
lever A, is moved to throw the drum into gear, the pin I, on a projection of
the friction lever presses against the curved part of the oscillating lever C,
and releases the foot brake.
Describe the friction blocks and their action,

1142
Hoists.
Ans. The friction blocks consist of sections of hard wood
bolted to the gear wheel which is keyed to the shaft. The
adjacent flange on the drum has inclined rings which register
with the bevel on the friction blocks. The endwise movement
given the drum by the friction lever brings the rings into fric-
Eguim yene ed!!
209
164A 10
77
162 Waste Cock Hand Lever
163 Waste Cock
164 Waste Cock Connection
1641 Waste Cock Connection inom
173 Waste Cock Lever Shaft
206 Crank Shaft Center Pillow Block
208 Waste Cock Lever Shaft Collar
209 Waste Cock Lever Shaft Arm on
Shaft 173
88
312
313
(not shown)
to
207 Crank Shaft Center Pillow Block Cap 314
(not shown)
310
310
310 Quadrant Rod
311
T
NOTTOB
OTOR 319
361
Friction Lever Shaft
358
J
350 Dial Indicator Pinion
360
Fig. 29. Combined friction drum and brake and reversible link motion steam
mining engine.
359
210 Waste Cock Lever Hub on Shaft 173 351 Dial Indicator Worm
305 Hand Lever Shaft
309 Friction Stub End Lever
354
746
49
op
Connection for Stub Lever 309
Connection for Lever 110
Lever for Connection 312
315 Lever for Connection 313
346 Screw Collar Thrust Plate for Drum 360 Dial Indicator Dial
349 Dial Indicator Rim Wheel
409
32
36
352 Dial Indicator Warm Wheel
353 Dial Indicator Worm Bracket
354 Dial Indicator Support Column
355 Dial Indicator Vertical Shaft
356 Dial Indicator Mitre Gear Bracket
357 Dial Indicator Mitre Gear
358 Dial Indicator Mitre Gear Shaft
359 Dial Indicator Hand
bhd
361 Dial Indicator Fingers
172 Foot Brake Pedal
bold nois

Hoists
1143
istby
107
47
39
35
114
39
115
108-109 110
108A- tog A
116
117:
пол-
112
38 58 30A 34
101 Link Rock Shaft
102 Link Arm
103 Link Connection
104 Link Guard
105 Link
105a Link Block and Pin
106 Link Jaw
107
99A
65-
33-
40
49
30
40
104
eals
105
105 A
weinig 10
108 Brake Lever,
103
To 1010 106a Link Jaw Support Stem
102
106
108a Brake Lever Latch
109 Reverse Lever
109a Reverse Lever Latch
110 Friction Lever
FOI
107 Quadrant Stand Frame of
fatw
35
48-A
od bor
ved baik
line begol
Figs. 30 to 33.-Construction details of the reversible steam hoist shown in fig.
29, showing especially the link motion reverse gear.
bein
34
37
115 Larch Connection
116 Latch Guide
117 Latch Spring
82 A
110a Friction Lever Latch
111 Ratchet Detent Quadrant
112 Reverse Detent Quadrant
113 Bracket for Friction Lever Shaft
114 Latch Handle
911
Ant

1144
Hoists
tional contact with the blocks, thus preventing the drum turning
on the shaft since the latter is keyed to the gear wheel.
Brakes
What is usually fitted to loose drums and why?
Ans. Band brakes in order to reduce the wear on the friction
blocks.
Fig. 34.-Clutch winches as applied to two or three drum hoist. In construction,
they are bronze bushed and driven by steel spiral jaw clutches; these winches
are engaged by bronze faced shifters, actuated by latched hand levers.
Ratches and pawls allow the load to be suspended from the winches while the
drums are being used. A collar on the end of the shaft with studs and double
nuts take the thrust.
What is provided to push the drum out of contact with
the friction blocks when the thrust pin is withdrawn by
the engineer?
Ans. A spring.
Hoists
1145
What is the effect of water or oil on a brake?
Ans. It practically destroys the friction with the result that
they won't hold the load.
BOOM FALL ROPE
What should be done?
Ans. Wipe off moisture or oil all that you can and dry out
by dusting brake wheel with lime or cement.

MAIN
ROIST B.
DERRICK
SWINGING ROPES
Fig. 35.-Double drum steam hoist with boom swinging gear for operating a
radial derrick. The machine is so constructed that operations of hoisintg the
load, raising and swinging the boom may go on simultaneously.
What causes glazing?
Ans. The presence of foreign matter such as dirt, oil, etc.,
between the wheel and lining.
1146
Hoists
123 Pinion Winch Head
124 Idler Gear Wheel
125 Gear Wheel
126 L. H. Swinging Drum
127 Pipe Separator
128 Idler Gear Wheel Pin
129
Friction Pinion
130 Arm Wheel

131
L. H. Bedplate Extension
132 Steady Arm Stop
133 Friction Screw
134
Connection.
135 Friction Lever
136 Drum Washer
137 Friction Woods
138 Clamp Lever
139 Friction Plate
140 Friction Nut
141 Lever Shaft
142 Steady Arm
143
Intermediate Shaft
144 Steady Arm Bolt
145 Swinging Drum Shaft
146 Tie Bar
147
Friction Lever
148 Clamp Lever
149 Crossrail
150 Idler Pinion
151 Arm Wheel
152 Friction Wood Bolts
153 R. H. Intermediate Shaft Cap
154 R. H. Swinging Drum Shaft Cap
155 L. H. Intermediate Shaft Cap
156 L. H. Swinging Drum Shaft Cap
157 R. H. Bedplate Extension
Lever Handle
158
159 Lever Handle Quadrant
160 Idler Pinion Pin
161 R. H. Swinging Drum
162 Clutch
163 Stud for Swinging Drum Shaft
164 Hand Lever
1
165 Guard Band for Driving Wheels
166 Lever Guide
167 Spring
168 Lever Latch
Tie Bolt
169
170
Guard for R. H. Side
171 Guard for L. H. Side
Connection
172
173 Split Thrust Collar
123
123
THIS SERIAL NUMBER IS STAMPED HERE
AND ON THE FRONT END OF EACH SIDE
FRAME OR ON THE BRASS PLATE ONR. H.
SIDE FRAME.
127
159
124-
165
124
128 173
152.
135.
132
141-
132
172
147
149
173-
158
ATI
147.
1-169
127
155-
141
134
53-
-
.164
135
142
159
166
1/167
168
172
Figs. 36 and 37.-Swinging gear unit and list of parts.
125
160
156
129
137
138 139
140
133
H44
129
A
125
148
139
-137
150
!|!! ·
162
160 150
134
1126
130
130
קווה?
15
429
151
136
163
154 157
151
-131
L146
161

170
-171
131
OR
157
Hoists
1147
How is the glaze removed?
Ans. By scraping.
Multi-drum Hoists
What is the object of multi-drums?
Ans. They adopt the hoist to service of a universal character
such as the working of a radial derrick where frequently several
operations have to be performed at the same time.
Describe the operation of the two drum hoist.
Ans. The forward drum is for hoisting the load and the other
for raising the derrick boom. Between the drums and winch
heads are two spools for the derrick swinging ropes. With this
arrangement the operations of hoisting the load, raising and
swinging the boom can go on simultaneously.
What is a winch head?
Ans. A short hoisting drum or spool having curved flanges
and attached to an extension on the drum shaft.
How are they attached?
Ans. The winch heads are secured to the shaft by a sliding
key having a sleeve upon which the swinging spools revolve.
How is the friction drive arranged?
Ans. Friction drive adequate for the full power of the engine
is used between the swinging spools and the winch heads. The
frictional contact is provided by cams placed between the
swinging drums and the frame of the engine; on the other side
are anti-friction collars to take up the thrust.
1148
Hoists
Describe the operating gear.
Ans. The operating cams are connected by links to the end
of a lever which is carried on a shaft extending across to the
side where the engineer stands, and where the vertical detent
lever for operating the swinging device is placed.
How are the two swinging spools connected to the
derrick?
Ans. A rope is wound on the rim of the bull wheel of the
derrick and secured to the same in the center. Each of the two
ends of the rope is fastened to one of the two swinging spools,
enough rope being wound on each to give the required amount
of motion to the bull wheel.
What is the bull wheel?
Ans. On radial (swinging) derricks a large wheel at the base
of the derrick consisting of a circular flange made of structural
T iron to which the boom swinging ropes are attached.
Describe the winch operation.
Ans. The engineer by throwing the lever forward engages
the friction clutch on that winch, causing it to rotate and wind
in the rope, which turns the boom in one direction. The other
winch meantime paying out the rope.
How does the friction mechanism work?
Ans. The construction permits the swinging operation since
the same movement which engages one friction, disengages the
other. By throwing the lever backward, the friction of the rear
spool is engaged, and the forward spool released. Thus the
boom can be turned in either direction.
Hoists
1149
BULL WHEEL
How are the cams constructed?
Ans. The cams operating the frictions are so constructed that
when the operating lever is in its central position, there is
enough frictional contact in the swing spools to keep the ropes
taut. Accordingly, when one spool is winding in the swinging
rope, the other has sufficient friction to prevent the rope which
is paying out, over running.

BOOM
SWINGING
ROPES
LEIMA
THE W
MATERI
GALMMNUKIIMALIMUM III
T
Th
MID
J
***
HOISTING ROPES
Fig. 38.-Base of a radial derrick showing the bull wheel and boom swinging
ropes, also the ropes for hoisting and raising the boom.
Operating Directions
What is the first operation?
Ans. The engineer first throws in the front friction drum
lever sufficient to hoist the load. He is then free to handle the
boom, either raising or lowering it with the rear drum.
1150
Hoists
How is the boom lowered?
Ans. It should be done by both the friction lever and a slight
pressure on the foot brake.
Why?
Ans. It prevents the oscillating lever falling into place and
locking the brake.
What else does it do?
Ans. It allows control over the lowering speed of the boom,
and as soon as it is lowered far enough, then full pressure is
put on the brake lever and the friction lever thrown out when
the oscillating lever falls into place and locks the brake fast.
What is the advantage of the use of the two levers in
combination for lowering the boom?
Ans. It is a safety provision against the possibility of the
foot slipping off the foot brake.
What precaustion should be taken when the boom drum
is not in use?
Ans. It is important that the engineer keep the safety lever
locked to the foot brake and also the pawl applied at all times
when the boom drum is not in use.
Give an exception to this rule.
Ans. The only exception is when working with a short boom
and the time required to throw in the pawl is too valuable
to lose.
What is depended upon in such cases?
Ans. The safety lever locked to the foot brake performs all
that is required of the pawl and ratchet.
Hoists
1151
When is the use of the safety lever locked to the foot
brake desirable?
Ans. It is desirable with a long springy boom in chaining or
dogging rock after a blast, at which time it may not be known
whether the rock which it is intended to hoist is free.
What is the effect of applying the strain for hoisting the
rock?
Ans. It springs the boom and if the dogs fly loose, or the
chain break, the boom springs back to its normal position,
slackening for an instant the boom fall rope, which may throw
out the pawl causing the boom to fall.
Hoist Terms
There are a number of terms relating to hoists and hoist-
ing apparatus which are given here and which will be found
helpful in understanding the subject.
Aerial dump.-An improved type of conveyor having low sides,
and open at one end. The form facilitates the handling of material by
a cableway.
Boom fall rope. -The rope which operates the vertical movement
of the boom of a derrick.
Boom swinging gear.-A device for operating a radial or boom
swinging derrick. It consists of a drum, or two spools on which the
boom swinging ropes are simultaneously wound, and unwound.
Bull wheel. On radial derricks, a large wheel at the base of the
derrick consisting of a circular flange made of structural T iron to
which the boom swinging ropes are attached.
Clam shell crab.—A term used to describe a form of bucket used in
dredging, excavating, and conveying loose material such as coke, sand,
etc.
1152
Hoists
Cone.—An iron cone shaped cap used in logging operations to assist
the log to pass over obstacles when skidding.
Derrick swinging ropes.-The two ropes which control the radial
position of the derrick, or by means of which the derrick is made to
revolve.
Differential brakes.-Band brakes, in which both ends of the band
are pivoted to the rocker but at different distances from the center of
the load held, tending to turn the rocker in the direction to apply the
brake.
Dock wheels.-Small cast iron wheels fitted to hoists and forming
a running gear, for use on docks or places where it is necessary to
move the hoist frequently.
Drum.-A revolving flanged cylinder, to which the hoisting rope
is attached.
Drum Spring.-A spiral steel spring which pushes the drum out of
contact with the friction woods when the friction pressure is released
by the friction lever.
Dumping block.-A form of block consisting of a small and large
wheel. A piece of chain inserted in the hoisting rope at the right point
causes the small wheel to revolve which raises the back end of the
skip, and allows the load to dump.
Fixed drum.-A type of drum in use where only single loads have
to be handled.
Foot brake.-A band brake for controlling the movement of the
drum.
Friction lever latch.-A device consisting of a thumb latch and
detent, engaging with serrated teeth in a quadrant, by which the lever
is held in any desired position.
Friction nut.-A large nut at the end of the drum shaft and
attached to the side stand. The friction lever screw works in this nut
and communicates motion to the friction pin.
Friction pin.-A steel pin which communicates lateral motion from
the friction screw to the drum, bringing the latter into contact with
the friction woods.
Friction screw. -A powerful steel screw located near the end of
the drum shaft and operated by the friction lever. It communicates
motion to the friction pin.
Hoists
1153
Friction woods.-A concentric layer of wooden blocks attached to
the gear wheel, at the end of the drum, and furnishing the frictional
contact between the two.
Guard bands.-Protecting wrought iron bands fitted over the gear
wheels to prevent the rope or any obstruction getting in the teeth of
the gear.
Locking levers.-On double friction drum engines designed for
handling a boom derrick. When the friction lever is moved, for the
purpose of throwing the drum into gear, the pin on the end of the fric-
tion lever presses against the curved part of the oscillating lever and
releases the foot brake. When the lever is moved back, the operator
places his foot on the foot brake for a moment, and the oscillating lever
drops back into its original position, thereby locking the brake on
the drum.
Loose drum.-A drum, free to revolve on its shaft, and which is
thrown in or out of engagement with the driving shaft by means of a
clutch.
Main hoist rope.-The rope which raises or lowers the load.
Operating levers.-Devices for operating the brake, friction, etc.,
in hoisting. They are usually assembled together and conveniently
located for the engineer.
Orange peel grab.-A term used to describe a dredging device
which when opened assumes the shape of an orange peel divided into
four parts.
Outhaul rope.-In logging operations, an auxiliary rope, worked
by a separate drum. It is used to carry the skidding rope out into the
woods, which, by former methods had to be done with mules or men.
Post brakes.-A type of brake in use on reversible, mining, and
hauling engines.
Radial ribs.-Cooling ribs placed outside of the drum friction
surfaces to assist in carrying off the heat generated.
Shrouded ratchet ring.-A ring having ratchet teeth around its
circumference and bolted to the drum flange. The outer edge of the
ring is provided with a shrouded flange, thereby preventing the teeth
being broken by the pawl, or the pawl slipping off.
Side stands.-Supporting frames usually of T shaped section and
designed to carry both the drum and crank shaft bearings.

1154
Hoists
Skip. An iron box with a bale holding from one to ten tons of ore
or rock; used for hoisting and running between guides, or in inclined
shafts to run on a track.
Sluing drums.-Two pony drums located on one shaft, and espe-
cially adapted for the operation of radial or swinging boom derricks.
Snaking and loading machine.-In logging, a hoist with rigging
so arranged that the operations of hauling and loading may be carried
on from separate booms independently and at the same time.
2538
Fig. 39.-Silent chain drive for gas hoists.
Stiff leg derrick.-A form of derrick fitted with wooden braces
instead of guy ropes for support.
Tail sheave.-A pulley used in the "pull boat system" of logging.
Winch head. A short hoisting drum or spool having curved
flanges, and attached to an extension of the drum shaft.
Gasoline Hoists
Gasoline and steam hoists have many parts in common, the
principal difference being in the transmission, or method of
transmitting the power from the prime mover to the driving
shaft.

Hoists
1155
bour m
Whereas, the steam engine with its great torque range, re-
quires only a single reduction gear, and in some cases is con-
nected direct to the drum (direct drive) but the gas engine with
its inherent defects, chief of which is having to depend largely
on fly wheel effect to keep going under heavy load, requires a
600 SWI
Alor no b
hub Ruby
1264 110
Fig. 40.-Double cone type friction for gas hoists.
Fig. 41.-Automatic mechanical brake for gas hoists.
SPICE POPE
bonilozisi)

1156
Hoists
Gasoline derrick-
lighter hoists
TOUR
A
JU
Fig. 42.-Gasoline derrick lighter hoist. This five drum gasoline hoist is one of the several furnished to the
New York Central Railroad to operate their 10 ton derrick lighters. The hoist has three main drums for the
boom and two hoist falls and two smaller boom-swinging drums, one on each side, which are driven through
flexible couplings from the main drive shaft. The swing drums are mounted on self-contained welded steel
bases and run at one-half the speed of the main drums. The front drum shaft is extended and provided with
an independent clutch winch head for mooring. All levers are assembled in quadrant which is located in
operator's cab directly above hoist.

Hoists
1157
double reduction gear between engine and drum; that is, the
gas engine must run at a much greater rotative speed than the
steam engine to prevent stalling.
In addition to the spur reduction gear between drum and jack
shaft a second gear is placed between the jack shaft and the
اندار 5
Fig. 43.-Single drum gasoline hoist. Note silent chain drive enclosed in casing
and which operates in a bath of oil.
engine, a good type being the silent chain drive as shown in
fig. 39.
This drive is in intermittent service. It is idling during all
lowering, loading, unloading and waiting period. This must be

1158
Hoists
Fig. 44.-Triple drum Diesel powered heavy duty hoist seen from operator's side.

Hoists
1159
――――
evident the gas engine must run all the time whether it be
working or not, because it is not practical to start and stop
a gas engine every few minutes.
Round
VEBO
In eloquent contrast to this starting and stopping, a steam
engine is simply a matter of opening and closing the throttle
CO
SULLIVAN
Fig. 45.-Single drum Diesel shaft hoist. It can be geared for 18 different
hoisting capacities, using one of four different power units and lifting from
1660 lbs. at a speed of 600 feet per minute to 6450 lbs. at a speed of 275
feet per minute.
valve. Moreover in the case of the two cylinder steam hoist
with cranks at 90 there are no dead centers, that is, the engine
will start in any position without any "kicking" the fly wheel
or cranking as in the case of a gas engine.
A typical friction consists of maple blocks with their cork
inserts as shown in fig. 36. Usual practice on chain drive gas

1160
Hoists
hoists of 30 horse power and above, is to locate the brakes on
a brake flange opposite the friction, except on builders' hoists
which carry two brakes.
A
Fig. 46.-Heavy duty double drum electric hoist. Silent chain drive. Where an
extra heavy duty hoist is needed and where the braking service is very severe,
the double drum hoist illustrated here is built to meet these requirements.
These hoists embody many new features and represent a distinct advance in
hoist construction. They have been designed largely in response to the demand
from contractors who are engaged in large hydro-electric projects or in work
of similar magnitude. This hoist employs the silent chain drive and has two
sturdy brakes on each drum. Large ventilated brake flanges carry off the
heat caused by severe braking service.
Electric Hoists
The first electric hoist is said to date back to 1890 and since
then it has reached a high state of perfection. Like the gas
hoist, it employs double reduction gearing with chain drive.
Fig. 41 shows an automatic mechanical brake, located on the inter-
mediate shaft of chain driven machines (except drag scraper hoists)
protects the ascending load as long as the drum or drums remain
engaged with the frictions.

Hoists
1161
Frictions and brakes are practically the same as for gas hoists.
Motors specially designed for hoisting service are used. Alter-
nating current motors are of the slip ring varying speed induc-
tion type, except drag scraper hoist motors which are squirrel
cage type. Direct current motors are series wound, and well
Fig. 47.-Air driven hoist powered with a "turbine air" motor. The hoist shown
has a 16 h.p. motor capable of lifting 2060 lbs. at 240 ft. per minute.

protected from dust and moisture frequently associated with
hoisting work. The standard available power is alternating
current 3 phase, 60 cycle, 220, 440, 550 volts or direct current
230 volts.
Fig. 46 shows a heavy duty double drum electric hoist with
silent chain drive. The large ventilated brake flanges carry off
the heat caused by severe braking service. It is suited to the
needs of contractors who are engaged in large hydro-electric
projects or in work of similar magnitude where braking
service is very severe.


1162
Hoists
terte aa
inb
ol burial, vitsioons.
LEDGERMO00
2394
Fig. 48.-Electric swinger with overhung drums. The hoist here shown is a
triple gear reduction swinger, equipped with a reversing motor. One drum is
keyed fast to the shaft and the other drum is provided with a take up device.
A brake wheel is keyed on the first intermediate shaft, and on this wheel is
mounted a powerful double acting brake band. This brake is usually operated
by a foot lever at the left rear side, convenient to the operator. If required,
extensions for remote manual control can be provided.
Steam Turbines
1163
I
CHAPTER 56
Steam Turbines
What is a steam turbine?
Ans. By definition, a prime mover in which gradual changes
in the momentum of a fluid are utilized to produce rotation of
the mobile member Jude.
A turbine is a machine in which a rotary motion is obtained by the
gradual change of momentum* of a fluid-Neilson.
A turbine is a prime mover in which a rotary motion is
obtained by centrifugal force brought into action by changing
the direction of a jet of steam escaping from a nozzle at high
velocity-Graham.
What are the essential parts of a turbine?
Ans. A disc mounted on a shaft and having attached to its
rim a multiplicity of curved vanes and at the side a nozzle (or
nozzles) out of which a jet of steam is directed to the vanes
tangentially.
Does the pressure of the steam cause rotation?
Ans. No.
*NOTE.—By "change of momentum" he means by change in direction of the
momentum.
1164
Steam Turbines
What causes rotation?
Ans. Centrifugal force created when the direction of the fast
flowing jet of steam is changed, its momentum being changed
into centrifugal force.
Describe this action more in detail.
Ans. In fig. 1, V,V', are curved vanes attached to the circum-
ference of a disc or rotor W. At one side and placed at an acute

v!
-W-
MI
Fig. 1.-Diagram showing principle of turbine operation.
angle with the rotor, is a steam nozzle N. In operation, steam
issuing from the nozzle at high velocity has its direction changed
by the curved vanes and centrifugal force is created due to
changing the direction of flow of the steam.
Explain more about the centrifugal force.
Ans. It must be obvious that the rotation of the wheel is
caused by centrifugal force acting against the forward vanes,
Steam Turbines
1165
and not by the pressure of the steam. For if the curved passages
be closed, thus bringing the steam to rest, it would press equally
against the vanes V and V', since these present equal areas,
there would be no excess force tending to cause rotation.
This is shown in fig. 7 and the reason for rotation in fig. 8.
NO
ROTATION
(REACTIVE)
CENTRIFUGAL FORCE ZERO
TANGENTIAL COMPONENT ZERO
MAXIMUM
ROTATION
D @
(REACTIVET
CENTRIFUGAL FORCE MAXIMUM
TANGENTIAL COMPONENT MAXIMUM


Figs. 2 and 3.—Diagrams showing condition of no rotation and condition of
rotation in turbine operation.
1. Impulse.
2. Reaction.
3. Impulse and reaction.
Classification
There are numerous types of turbines and they are classified
in several ways, a common yet very questionable division being,
with respect to the action of the steam as:
1166
Steam Turbines
This so called classification will be taken up later.
Other classifications are:
1. With respect to whether there be one or more revolving
vane discs, separated by stationary reversing vanes.
a. Simple.
b. Compound.
2. With respect to the number of step reductions, as:
a. Single stage.
b. Multi-stage.
3. With respect to the direction of steam flow as:
a. Axial.
b. Radial.
c. Tangential.
d. Mixed.
e. Helical.
ƒ. Re-entry.
4. With respect to the source of the steam as:
a. Extraction.
b. Accumulator.
5. With respect to pressure of the steam as:
a. High pressure.
b. Mixed pressure.
c. Low pressure.
6. With respect to the terminal pressure as:
a. Non-condensing.
b. Condensing.
Steam Turbines
1167
As to the Terms
Impulse and Reaction
(Especially Impulse)
The terms impulse and reaction have specific meanings in
turbine engineering parlance. These specific meanings are dif-
ferent from the meanings of the same words as they are em-
ployed in physics, mechanics and ordinary usage. There is little
connection between the usual meaning of the words impulse and
reaction and the specific ideas they are intended to convey in
steam turbine parlance-Croft.
wing
A German writer uses equal pressure for impulse and unequal pressure
for reaction; Croft considers these terms more appropriate and so does
the author.
These terms are somewhat misleading because all practical turbines
operate by the action and reaction of the working fluid and it would
be clearer to designate the two types in some other way-French.
Terms descriptive of turbines and their parts are used with different
meaning by different writers and manufacturers-Croft.
Perhaps the real reason for all this confusion is the acceptance
of loose misleading definitions* for the terms impulse and
reaction.
*NOTE.—In the beginning some language butcher, perhaps dating back to the
rough stone age, put over some slipshod definitions and owing to the power of
suggestion, they have become so firmly rooted that nothing can be done about it,
so as Stravinski said about his alleged music: "Take it or leave it.
""
Define the term impulse.
Ans. The act of impelling or suddenly driving forward in the
same direction as the applied force.
Note especially the definition means that the force is applied nor-
mally (that is perpendicular to the surface of the object acted upon)
causing it to move in line with the force.
1168
Steam Turbines
Define the term reaction.
Ans. Reverse action; a force acting in opposition to or
balancing another force.
What is an impulse turbine?
Ans. The term is a misnomer.
What causes a so called impulse turbine to rotate?
Ans. It is not impulse, but the reaction due to centrifugal
force-specifically the reactive or centrifugal force component

MOVEMENT
OF CAR
IMPULSE
1
Fig. 4. Elementary diagram illustrating impulse.
of the kinetic energy, dynamic inertia, momentum or vis viva,
or whatever you want to call it, of the fast flowing steam.
Give an illustration of impulse.
Ans. If a man direct a fire stream at right angles to a board
attached to a car as in fig. 4, the force of the stream of water
will move the car in the same direction as the flow of the water.
In what type turbine could impulse possibly occur?
Ans. Mathematically but not physically, in a turbine having
flat radial vanes, but even in this primitive arrangement there
is only one instantaneous position when there is impulse.
Steam Turbines
1169
Explain.
Ans. In fig. 5 when the flat blade is at 90° to the axis of the
jet or nozzle, impulse takes place but since the time interval of
action is
dt
or zero
hence even in this position there is physically no impulse.

90°
IMPULSE
(100%)
INSTANTANEOUS BLADE
POSITION 90° TO AXIS
OF JET
Fig. 5.-Elementary diagram illustrating the only instantaneous position of
blade of so called impulse turbine for 100% impulse as explained in the text.
Give an illustration of reaction.
Ans. This is illustrated by the Scotch mill shown in fig. 6.
The real force that causes this device to rotate is centrifugal
force. It is called reaction because the curved shape of the pipe
"gets in the way" of the flowing water forcing it to change its
direction, thus introducing centrifugal force which presses against
one side of the curved pipe which reacts, causing rotation.
1170
Steam Turbines
Strictly speaking what causes rotation?
Ans. The tangential component of the centrifugal force.
Give an illustration.
Ans. In fig. 9, let the nozzle point in some direction between
radial and tangential.

TR
BEARING
CENTRIFUGAL
FORCE
ACTING UPON PIPE TO CAUSE
ROTATION
JET
API
SUPPLY
PIVOT
ROTATION
Fig. 6.-Elementary "Scotch Mill" reaction turbine.
JET
Steam Turbines
1171
If P, be drawn to length to represent the centrifugal force introduced
by the curvature of the pipe, then will tangent T, of the right triangle
represent the force available for causing rotation, this in amount
tangential component.
NO ROTATION
EQUAL PRESSURE
What happens when the blade of the pin wheel shown
in fig. 5 points in any other direction?
CLOSED
ROTATION
CENTRIFUGAL FORCE THROWS STEAM
AGAINST FORWARD VANE
-


HIGH PRESSURE
ROTATION
LOW PRESSURE
Figs. 7 and 8.-Diagram showing condition for no rotation and for maximum
rotation.
Ans. The changed angularity of the jet with the surface of
the blade introduces centrifugal force with a resulting reaction.
Explain in detail.
Ans. In fig. 10 let the blade be at some other angle to the
jet other than 90°. Let AB = kinetic energy of the jet and
draw AC normal to the blade. In the triangle ABC, the kinetic
energy of the jet is made up of two components: AC, which is
1172
Steam Turbines
the component available to cause rotation when the wheel is
in the position shown, and BC, which represents non-active or
wasted energy*.
What does the component AC represent?
Ans. The reaction on the blade due to centrifugal force and
that is what causes rotation at that instant.

R
T
TANGENTIAL COMPONENT
(CAUSING ROTATION)
REACTIVE
CENTRIFUGAL FORCE
Fig. 9.-Diagram plan of "Scotch Mill" reaction turbine explaining tangential
reactive component which causes rotation.
*NOTE.—Electrically speaking in the case of alternating current, BC corres-
ponds to a wattless component when the voltage and current are not in phase.
Steam Turbines
1173
i
Equal pressure or Velocity Turbines
(So called Impulse Turbines)
1. Simple.
What are the distinguishing features of turbines of this
type?
90°
Ans. Steam after expansion in the nozzle (to generate veloc-.
ity) enters and leaves the passages between the vanes at the
same pressure.

A
KINETIC ENERGY OF JET
NON-ACTIVE COMPONENT
REACTION
(NORMAL OR ACTIVE COMPONENT)
Fig. 10 -Diagram illustrating reaction component.
The sectional views and diagram figs. 11 to 13 show essentials of
the turbine.
Describe the nozzle.
Ans. It is of the diverging type as shown in fig. 14.
Note names of parts, also that the velocity of the steam increases
as it passes through the diverging section, that is, from A to B. This
is due to expansion.
1174
Steam Turbines
What is the actual construction of nozzles?
Ans. A leading manufacturer specifies as follows: Nozzles
are made of Monel metal accurately formed over special dies.
Each nozzle is individually designed for proper expansion of
steam at the pressure and temperature specified. Steam passages
to the nozzles are outside the casing. A secondary nozzle with
I
NOZZLE
NOZZLE
INITIAL
PRESSURE
INITIAL
VELOCITY
ZERO
PRESSURE
CASING

WHEEL
VANES
WHEEL
ון מן
SHAFTI
LOST
VELOCITY
CONDENSER
FRESSURE
Figs. 11 to 13.-Simple impulse turbine and pressure velocity diagram. In oper-
ation, the steam is completely expanded in the nozzles, being reduced to
condenser pressure at the outlet. The velocity falls in passing through the wheel,
a certain amount of energy being lost by the inability of the wheel to absorb
all the velocity generated in the nozzle.
Steam Turbines
1175
hand valve which when closed gives full load economy at partial
loads, or if the main nozzle carry the normal load, the secondary
nozzle may be opened for increased load or to compensate for
lower steam pressure.
INLET
Describe the shape of the vanes or blades and why?
Ans. The steam walls of the vanes are in this type turbine
of circular form, the distance between the walls at all points
((
THROAT
DIVERGING
OUTLET

B
VELOCITY
INCREASED:
1
EXPANSION TAKES PLACE HERE
Fig. 14.-Diverging type steam nozzle as used in equal pressure or velocity
turbines; alleged impulse turbines.
from inlet to outlet being the same so that no expansion will
take place in the passage between adjacent vanes.
What is the construction of the vanes?
Ans. They are usually made of stainless steel. In the design
shown in fig. 15, they are held in machined slots in the wheel
by steel cross pins, two pins in each blade. Blades are shrouded
by inner and outer bands of stainless steel which confine the
steam to a full working passage. The inner bands also protect

1176
Steam Turbines
the wheel from steam erosion. The outer tip of each blade is
machined to form a rivet which extends through and is pressed
over the outer band, thus forming a rigid assembly. Vanes are
removable and renewable.
Describe the casing.
quite at onload
Ans. The casing is made of cast iron or steel, depending upon
service conditions and is suitable for back pressures up to 50 lbs.
S
Fig. 15.-Single stage equal pressure or velocity turbine wheel and blade
assembly.
tilolay um loups
It is horizontally split and the casing is subject to exhaust
pressure only. A relief valve is provided. Larger sizes have two
exhaust openings one on each side.
Mbyl
What type bearings are provided?
Ans. The bearing shells are babbitt lined or solid lead bronze
and are ring oiled. They are horizontally split and may be
rocked out of position and replaced after removing caps. Cart-
ridge type water cooling coils are provided. Deflector rings seal
the housings and prevent entrance of dirt, moisture or steam.
Oil level is determined by glass oil level gauges.nl of mos

Steam Turbines
1177
What are the two governors provided?
Ans. The constant speed governor and the emergency over
speed governor.
How is the constant speed governor controlled?
Ans. By fly balls.
How does it work?
4917
Fig. 16.-Single stage equal pressure or velocity mechanical drive turbine.
Ans. A varying load on the turbine will cause a momentary
decrease or increase in speed and the centrifugal force of the fly
balls, acting against the governor spring, moves the governor
plunger in or out. This movement when transmitted to the
governor valve by the governor lever opens or closes the valve,
increasing or throttling the flow of steam commensurate with
the load, and effects the return to normal speed,

1178
Steam Turbines
How is the governor lubricated?svog owl sd1 9 30dH
Ans. All governor parts are automatically oil lubricated. Oil
from the main bearing is fed into the governor housing, there
it is picked up by the governor hub, sprayed over all governor
parts, and is then returned to the main oil reservoir. i woll
Trip Valve Assembly
Strainer
Governor Valve
Cage
dow 29ob woll
2905
Hand
Valve
ຂາວ )
Governor Valve
Assembly
Fig. 17. Single stage equal pressure or velocity turbine steam chest showing
accessibility of governor and trip valves.
What is the function of the over speed emergency
governor?
Ans. It is to stop the flow of steam at a pre-determined over
speed, usually about 10 per cent above normal.
Describe its construction and how it works.
Ans. A spring loaded plunger is mounted in the governor

Steam Turbines
1179
hub and when over speed occurs the centrifugal force of this
plunger overcomes the spring tension, allowing the plunger to
move outward and strike the trip lever. This action releases
the trip latch and closes the trip valve, shutting off the steam
supply and stopping the machine.
Describe the speed adjustment.
Ans. Adjusting screw at lower end of governor lever is
Joosened for increased speed and tightened for lower speed.
CO
J
O
Fig. 18.-Single stage equal pressure or velocity turbine packing box and
carbon rings.
Additional speed adjustment of about 5 per cent may be made
at the governor nut on the end of the shaft after shutting down
the unit. Adjustment for lower speeds down to 50 per cent below
normal can also be made while in operation by further tighten-
ing the adjusting screw, but the governor will be inoperative
over this range.
Unh
well
Describe the shaft packing.
in
Ans. Shaft packing is carbon ring type, mounted in bronze
rustproof split housings, which have two compartments. Inner

1180
Steam Turbines
compartment contains two carbon rings, one ring being a four
piece self-adjusting type, having in. clearance between ends
of segments. As wear occurs the garter spring causes the
segments to close in around the shaft. The second ring is a two
Fig. 19.-Single stage equal pressure or velocity turbine nozzle, wheel and
reversing nozzle.
MONTERRE
agons adfliw forwzd
piece split type which seals the four piece ring and aids in
preventing leakage along the shaft. Outer compartment con-
tains one two piece split ring which diverts any leakage into the
drain. Stainless steel garter springs secure the rings around the
shaft and side springs hold them against the sealing faces.

Steam Turbines
1181
Shochu pomaliz
adilcao
What provision is made on condensing turbines?
Ans. Each box containing four carbon rings and top half
housing has a tapped connection for admitting seating steam
under 2 to 3 lbs. pressure.
Other details of construction are shown in the accompanying cuts.
05
Whe
Fig. 20.-Sectional view showing construction details of single stage equal
pressure or velocity turbine.
2. Compound.
What is a compound turbine?
Ans. One having two (or more) wheels keyed to one shaft
with reverse curve stationary vanes interposed.

1182
Steam Turbines
1-0
19/91 41
D-C
Fig. 21.-Dual driven pump DH steam turbine for automatic stand by power, suitable to provide stand-by
power for pumps, fans, blowers, and other plant auxiliaries, which are normally driven by constant speed
motors. Driven machine is usually provided with double extended shaft for connecting the turbine on the
opposite end from the motor. When the design of the driven machine does not permit double extended shaft,
the motor shaft is extended, and the turbine is mounted at the outside end of motor. Turbine then drives the
unit through the motor shaft. On these dual driven units the standard speed governor can be adjusted so
that the turbine will automatically pick up the load in case of electric power failure. This adjustment is easily.
made at the factory or by the operator in the field. With the unit in operation, motor driving, the adjusting
screw at lower end of governor lever is tightened, which closes the governor valve and shuts off steam flow.
Adjusting screw is then locked in that position and governor valve will remain closed as long as normal motor
speed is maintained. Upon motor power failure the unit immediately slows down, fly balls close in, and gover-
nor valve open admitting steam to the nozzles and picking up the load at a speed 3 to 5 per cent below
normal. Full speed can then be restored, if desired, by loosening the adjusting screw which opens the gover-
nor valve to full load running position. No other automatic control valves or devices are required.
Steam Turbines
1183
What is the object of the stationary vanes between the
moving vanes?
Ans. They act to deflect the steam after leaving the vanes
of the first wheel and cause it to enter the vanes of the second
wheel at the proper angle.
NOZZLE
SHAFT
NOZZLE-
INITIAL
PRESSURE
f
WHEEL
CASING

WHEEL
MOVING VANES
INITIAL
VELOCITY.
SSSSSS
WHEEL
STATIONARY VANES
MO
L
Figs. 22 to 24.-Compound impulse turbine and pressure velocity diagram.
Steam, after leaving the nozzles, passes through several wheels separated by
sets of stationary vanes.
Describe in more detail how the compound turbine
works.
Ans. Steam after leaving the nozzles, passes through the
1184
Steam Turbines
vanes of two (or more) moving wheels separated by stationary
re-directing vanes. As with the simple turbine the steam is
completely expanded within the nozzles, issuing therefrom at
exhaust pressure. The velocity generated in the nozzles is
absorbed in "steps" (not stages) as the steam flows through
MOVING VANE
PARTITION
COMPARTMENT
STATIONARY NOZZLES

CASING
WHEEL
ONE
STAGE
PARTITION
Fig. 25.-Detail of multi-stage turbine showing its distinguishing feature, that is
showing the partition between stages.
the moving vanes of the wheels and remains constant during
the passage through the stationary vanes.
What is the object of compounding?
Ans. To reduce the speed of rotation.
The essentials and operation of the compound turbine are shown in
figs. 22 to 24.
Steam Turbines
1185
INITIAL
PRESSURE
That is, the speed of rotation would not have to be so high as with
a single wheel in order to absorb the same amount of energy from the
steam.
111

INITIAL
PRESSURE
INITIAL
VELOCITY
S
DDI
ཕུ་་ང་ངང་་་་
TERMINAL OR
CONDENSER
PRESSURE

TERMINAL
PRESSURE
LOST
VELOCITY
Figs. 26 to 28.-Simple multi-stage impulse turbine and pressure velocity
diagram. The word "stage" relates to working pressure. In a multi-stage tur-
bine, steam, in passing through the turbine, works at several pressures. Modern
multi-stage turbines sometimes have as many as twenty to thirty stages.
In fig. 22 why are the vane passages gradually increased
in size in successive wheels?
1186
Steam Turbines
Ans. The velocity of the steam as indicated in the diagram
fig. 24 falls during its passage through the wheels, but remains
constant in passing through the stationary vanes. Since the
velocity is gradually decreased as it passes through the several
wheels, it must be evident that if the same quantity of steam
is to flow through successive wheels in the same interval of
time, the passages must gradually increase in size.
The passages through the stationary vanes are of uniform cross
section, because the velocity here is constant, however, it should be
noted that the second set of stationary vanes is larger than the first,
since the velocity of the steam is less at the exit of the second wheel
than at the first.
3. Simple multi-stage.
What is a simple multi-stage turbine?
Ans. One in which the pressure energy of the steam is progres-
sively transformed into kinetic energy in two or more pressure
stages, there being only one wheel to each stage.
What is the distinguishing feature of each stage?
Ans. There is a separate compartment for each stage as
indicated in fig. 25.
How does a simple multi-stage turbine work?
Ans. The word "stage" relates to working pressure. In a
multi-stage turbine, steam, in passing through the turbine,
works at several pressures. There is a separate compartment
and set of nozzles for each stage; the pressure of the steam is
constant in passing through a compartment, but drops succes-
sively as it passes through the several sets of nozzles, regener-
ating velocity at each reduction of pressure.
Steam Turbines
1187
The essential features and pressure velocity relations are shown in
figs. 26 to 28.
In operation, since there is only one wheel in each compartment, it
is evident that for efficient working, the velocity of the entering steam
must be proportioned to the speed of the wheel, and must be such that
it will be reduced to the exhaust velocity in passing through the vane
passages. For, since the entrance velocity depends on the amount of
pressure reduction at the nozzles, any excess velocity after leaving the
wheel represents an undue pressure loss, which otherwise would be
available for generating velocity in the second set of nozzles for the
second wheel. Now as the wheels run at slow speed the entrance velocity
should be moderate to avoid the loss just mentioned. Hence, with the
proper number of stages, the reduction of pressure at each set of nozzle
may be so proportioned as to give the correct entrance velocity to
avoid loss. The relations of pressures and volumes are clearly shown
in fig. 28.
What should be noted with respect to the pressure
velocity diagram?
Ans. It should be noted that the velocity falls to that of the
exhaust during each stage, being regenerated in passing through
each set of nozzle by successive reductions of pressure.
Name one inherent defect in the multi-stage arrange-
ment.
Ans. It is subject to leakage at points where the shaft passes
through the walls of the compartments which requires special
packing which is inaccessible.
4. Compound multi-stage.
What is a compound multi-stage turbine?
Ans. One in which the pressure energy of the steam is progres-
sively transformed into kinetic energy in two or more stages with
compound working in each stage.
Give another definition for this type turbine.
1188
Steam Turbines
Ans. A compound multi-stage turbine is one which has two or
more compartments, each containing two or more wheels and a
set of nozzles.
Figs. 29 and 30 show the essential features.
What is the object of such arrangement?

SHAFT
INITIAL
PRESSURE
INITIAL
VELOCITY
CASING
Md Tod
MOVING VANES
凍​劑
​STATIONARY VANES
NOZZLES
וונטון!
ZERO PRESSURE,
Figs. 29 to 31.-Compound multi-stage equal pressure turbine and pressure
velocity diagram. It is virtually two or more compound turbines joined in series,
or the equivalent, a multi-stage turbine having more than one wheel in each
compartment. The object of compounding is to reduce the number of stages,
especially in case of high initial pressure.
Ans. To reduce the number of stages necessary in a simple
multi-stage turbine especially for high pressure working.
That is, by placing two or more wheels in each compartment, a
greater pressure reduction may be made between stages thus reducing
the number of stages.
Steam Turbines
1189
INLET
How does the compound multi-stage turbine work?
Ans. Referring to the pressure-velocity diagram fig. 31 it will
be noted that the pressure remains constant in each compart-
ment, being reduced as the steam flows through the nozzles,
also, the velocity falls in two steps in each compartment, remains
constant in the stationary vanes, and rises in the nozzles.
PARALLEL

(rie
ふ
​=)
E
THROAT
THE S
OUTLET
CONSTANT PRESSURE
(NO EXPANSION)
Fig. 32.-Sectional view of nozzle with parallel sides.
J
Unequal Pressure Turbines
L
(Reaction Turbines)
What are the distinguishing features of turbines of this
type?
Ans. In turbines of this type, the nozzle has parallel sides
as shown in fig. 32 with such shape that the steam passes through
it at (practically) constant pressure; expansion takes place dur-
ing the steam flow through the wheel, the passages between
M
1190
Steam Turbines
adjacent moving vanes are of diverging cross section to permit
this expansion, thus reducing the pressure and increasing the
velocity.
How about the pressure on each side of the vanes (that
is each side of the wheel)?
CASING
BOILER
PRESSURE
VEL.IN STEAM
PIPE
SHAFT
MOVING VANES

STEAM PIPE →→→
-
AMAND
GUIDE VANES
MOVING VANES
GUIDE VANES
PRESSURE
VELOCITY
LOST VEL.
EX. PRESS.
EX.PIPE
LIVE
GUIDE VANES
MOVING VANES
Figs. 33 to 35.-Compound reaction turbine. In this type steam expands in
passing through the moving vanes instead of in the nozzle, as with the impulse
turbine type. The pressure falls gradually from inlet to outlet.
Ans. The pressure is less on the exit side than on the entrance
side.
How does this compare with the equal pressure or velocity
turbine, that is, the alleged impulse type?
Ans. The pressure is the same on each side of the wheel on
Steam Turbines
1191
these turbines, that is, the pressure is constant in passing
through the vanes since there is no vane expansion.
Describe the essentials and operation of the unequal
pressure (generally called reaction) turbine.
Ans. The principal parts consist of numerous rows of moving
vanes, separated by alternate rows of fixed guide vanes. The
passages through the latter are of increasing cross section, hence
part of the expansion takes part therein, being completed in the
wheel.
What should be noted about the fixed vanes?
Ans. They perform the function of nozzles.
Give further description of operation.
Ans. Figs. 33 to 35 show essentials and steam distribution..
The diagram fig. 35 indicates the increase of velocity as the
steam flows through the guide vanes and the decrease in passing
through the adjacent moving vanes. The pressure falls gradually
from the inlet to the outlet; it is, therefore maintained higher in
the turbine passages than the exhaust pressure, this being char-
acteristic of the reaction principle.
Give an illustration of reaction.
Ans. In fig. 36, showing sectional view of a tank on wheels. ·
and filled with water, if on one side there be an opening as
ABCD, the water will flow out relieving pressure of the area
ABCD. Now the corresponding or projected area A'B'C'D' on
the opposite side will be subjected to unchanged pressure. Thus
there will be excess pressure acting on area A'B'C'D' which will
tend to move the car to the left, that is, opposite in direction to
the motion of the outflowing water.
1192
Steam Turbines
*
The pressure at ABCD is that due to the friction of the water
passing through the short nozzle whereas the pressure at A' B'C' D' =
area A'B'C' D X pressure due to head of water.
Describe the effect of steam in passing through the mov-
ing vane passages.
Ans. In fig. 37, take any point as A, and draw tangent AB,
in length kinetic energy of steam and complete the right
REACTION
MOVEMENT
OF TANK
=

O
C
B.
WATER IN TANK
STREAM OF WATER
FLOWING FROM TANK
IMPULSE
Fig. 36-Elementary diagram illustrating reaction.
triangle ABC, then the conditions for the point A are BC= non-
active component and AC the reactive component due to
centrifugal force.
Does AC represent the entire turning force, explain?
Ans. No, the value of AC, should be determined for all points
from I to O, and the average taken, it being different at each
point because of the curvature of the vane.
Steam Turbines
1193
Thus in fig. 38, divide the vane passage into any number of zones and
draw force triangles for each zone obtaining, for instance, reaction or
centrifugal components a, b, c, d. The resultant will be the average of
abcd. Of course the more zones taken, the more accurate.
How is kinetic energy measured?
Ans. In foot pounds.
REACTION
(CENTRIFUGAL FORCE COMPONENT)
FORWARD VANE

ROTATION
A
passages.
LOW VELOCITY
NON ACTIVE COMPONENT
B
HIGH VELOCITY
KINETIC ENERGY
(MOMENTUM)
OF
STEAM
Fig. 37.-Diagram showing effect of steam in passing through the moving vane
Just what is kinetic energy?
Ans. The kinetic energy of a moving body is the work which
the body is capable of performing against a resistance before it is
brought to rest; that is, it equals the work which has brought
it from its state of rest to its actual velocity.
1194
Steam Turbines
How is the value of kinetic energy obtained?
Ans. The measure of kinetic energy is the product of the
weight of the body multiplied by the height from which it must
fall to acquire its actual velocity.
The kinetic energy of a body is expressed by the formula:
E
1/2 mV 2
W
but m =
ROTATION
g
substituting
in which
-

E
Fig. 38.-Diagram for obtaining the average value of turning force.
=
1/2 X
m = mass
d
W
S
C
g
ZONES
X V² =
WV2
2g
ľ
Steam Turbines
1195
I
!
!
E
W
kinetic energy in foot pounds
weight of the body in pounds
g= acceleration due to gravity
V = velocity in feet per second.
=
==
Applied to the turbine, the kinetic energy of the fluid passing
through the turbine is
Explain.
WV2
2g
= 32.2
where W
weight of fluid per second and V its velocity at
entrance. Evidently the smaller W, the larger V must be to
develop the same power. If the fluid leave the turbine with the
velocity Va, then
WV2
2g
represents the energy not absorbed by the turbine. If Va be
small, the wasted energy will likewise be small.
Does the construction in fig. 38 give the total reaction?
Ans. No, that is the reaction of only one vane.
Of course, the result there obtained must be multiplied by the
number of vanes to which steam is supplied simultaneously, that is,
the number of passages covered at one time by the nozzle or nozzles.
What must be considered with respect to reaction?
Ans. The speed of the steam and the tangential speed of the
wheel.
1196
Steam Turbines
Ans. In the velocity diagram fig. 39, let AB = tangential
speed at point A on the vane and AC, component in direction of
rotation. Now if the speed of the vane represented by A'C' =
AC, then the reaction will be zero because the vane will move in
the direction of rotation as fast as the steam will move in this
C
C
A" A
C

α
A
V
Fig. 39.-Diagram for obtaining the reactive velocity component or resultant
effect considering movement of the vane.
1
AC-A"C" aC = V
==
VANE
ROTATION
direction, that is, its component of motion in this direction.
Again if the speed of the vane A"C" then the reactive velocity
component will be
B
This gives the factor V, of the formula
WV2
2g
Steam Turbines
1197
Miscellaneous Turbines
What is a helical flow turbine?
Ans. A single pressure, multiple velocity stage machine de-
signed for helical flow.
How does it work?
Ans. The steam is expanded to exhaust pressure in the
nozzles, the steam jet being redirected back into the turbine
rotor from the stationary reversing buckets until its kinetic
energy is practically absorbed.
What is a bleeder turbine?
Ans. One in which steam is extracted at one or more inter-
mediate stages for industrial use, often at comparatively high
pressures.
What is a low pressure turbine?
Ans. One operating at approximately atmospheric pressure
and expanding to condenser pressure.
What is a mixed pressure turbine?
Ans. One designed to work on two or more pressures.
Erection
Instructions here given are for a simple single stage machine,
but considerable of which will be found to apply generally.
1198
Steam Turbines

78
22
25
79
80
81,
28
83
82
27'
29-
14
30-
#'OEU
୮୫ BE
IHANACADE
23
18
21
20
19
16
15
ล
74.
6A
75
Sib
5
72
71
L
****...*.
PACE
10
-12
13
-11
71
56
51
Fig. 40-Dean Hill type DH single stage turbine. Section through sleeve-bearing 'urbine. The numbers
refer to the accompanying list of parts
Steam Turbines
1199
=21
No.
1
2
Bottom Half Casing
Top Hall Casing
Wheel
3
4
5 *Packing Box
6 *Packing Rings (Inner and Outer)
6A *Packing Ring (Center)
*Shaft
7 *Garter Spring
9 *Bearing Seal Ring
10 *Bearing Housing (Coupling End)
11 *Bearing Shell (Coupling End)
12 *Bearing Shell Retaining Pin
13 *Oil Ring
14 *Bearing and Governor Housing
15 *Bearing Shell (Governor End)
16 *Locating Collar
17
*Governor Hub
18
Flyballs
19 †Governor Plunger Seat
20 +Governor Spring Seat
21
Governor Spring
22 +Governor Nut
23 †Governor Plunger
25 +Governor Ball Bearing
Governor Lever
27
28
Governor Lever Bracket
29 †Governor Lever Pin
PARTS LIST
No.
30 †Speed Adjusting Screw
31 †Governor Valve Stem Nut
32 †Governor Valve Stem Cradle
33 †Governor Valve Stem Packing
34 Steam Chest Head
36
37
38
39
Steam Chest
40
+Trip Plunger Adjusting Nut
41 †Trip Plunger Adjusting Nut
42 +Trip Plunger
43
44
45
†Governor Valve Spring
Governor Valve Stem
Governor Valve
46
47
48
Trip Plunger Spring
*Trip Lever
Trip Link
Trip Latch
+Trip Valve Stem Knob
Trip Valve Stem
49 +Trip Valve Stem Nut
50 +Trip Valve Spring
52 +Trip Valve Stem Packing
53
Trip Valve
Strainer
54
55
Main Nozzle Stand
56
Main Nozzle
57
58
Main Reversing Nozzle
Auxiliary Valve Stand
No.
59
60
Auxiliary Hand Valve
Auxiliary Nozzle Stand
61 Auxiliary Nozzle
62
71
Auxiliary Reversing Nozzle
Water Cooling Coil
*Packing Box Diaphragm
73 *Packing Box Cover
72
74 *Packing Retaining Pin
75 +Packing Compression Spring
78 *Inspection Cover
79 †Governor Ball Bearing Lock Nut
and Washer
80 +Governor Ball Bearing Housing
81 †Governor Link Pin Seat
82 †Governor Link Pin
84
83 +Governor Link Pin Bushing
Governor Hub Locking Pin
Trip Nut Set Screw
85
87
88
86 +Governor Lever Pin Bushing
Governor Valve Cage Pin
Governor Valve Cage
Governor Valve Stop Pin
†Trip Lever Pin
89
90
91 *Trip Lever Arm
92 +Trip Stem Packing Nut
93 Trip Valve Cage
94
Nozzle Stand Dowel Pin
These parts are interchangeable on DH-20 and DH-30 Sleeve Bearing Turbines.
✦ These parts are interchangeable on DH-20, DH-30 and DH-40, both Sleeve and Ball Bearing Turbines, 28 parts.
A total of 48 parts, designated by symbols and , are interchangeable on DH-20 and DH-30 Sleeve Bearing Turbines.
1200
Steam Turbines
How is the turbine usually mounted?
Ans. Usually on a continuous cast iron or steel base plate
which extends under the driven machine, and the two shafts are
connected by a flexible coupling.
What precaution should be taken?
Ans. Any base plate, no matter how heavily constructed, may
be sprung in shipment or may be distorted by an uneven sup-
port on the foundation, or by uneven tightening of foundation
bolts, or by the pull from improper pipe connections.
The flexible coupling will not compensate for misalignment. There-
fore after the unit is set on foundation, it is necessary to check align-
ment, making certain that the shafts of the turbine and of the driven
machine are in one line.
No machine will operate satisfactorily if the shafts be out of line
and serious troubles may develop such as bent shafts, worn bearings,
and worn coupling parts.
How should the foundation be constructed?
Ans. It may be either concrete or structural steel. Consult
the certified dimension drawing furnished with the machine for
size of base plate and size and location of foundation bolts.
When setting the unit on the foundation use wedges under the
base plate so that there is at least 1½ in. clearance between base
plate and top of foundation for grouting.
Describe the method of aligning.
Ans. Adjust the wedges so that the base plate is level and
then check alignment of coupling hubs. Pin and bushing type
couplings have wide flanges and are easily checked. Couplings
of the gear or spring type have enclosing covers, and these covers
must be disconnected and slid back along the shaft before align-
ment can be checked.
Steam Turbines
1201

3.
56.
55.
57
62
61
94
60
89898
-59
-58
Fig. 41.-DH turbine. Development through steam path. List of parts on page 1199.
1202
Steam Turbines
{
When cold, the turbine shaft should be set low to compensate for
upward expansion when the casing becomes heated. Allow .001 in. for
each inch in height from turbine feet to centerline of shaft. However,
when the driven machine is also heated, such as a hot oil or hot water
pump, the allowance need not be as great. Therefore it is necessary
to check alignment when cold and also after both members of the unit
have been heated to operating temperature.
What checking should be done after setting unit on the
foundation?
Ans. Check alignment by placing a straight edge on the
coupling flanges or both faces. Check at top, bottom and both
sides. Also insert calipers or feeler gauge between the coupling
halves to make certain that both faces are equidistant in any
position of the shaft.
How are corrections made?
Ans. Corrections may be made by "throwing" the base or
shimming under turbine or driven machine. Both the drive and
driven shafts must run freely with and without the coupling
bolts or covers in place. Pull down the foundation bolts, dowel
turbine and driven machine to base, then again check for align-
ment and make correction if necessary. The base may then be
grouted in.
When the turbine is mounted separately on its own foundation, with
or without sole plate, the method of installation and alignment is the
same as for units with continuous base plates.
How should the inlet line be installed?
Ans. The inlet line should be anchored at the header and
must have loops or offsets to provide flexibility so that expan-
sion of this inlet line will not exert undue strain on the turbine.
Install a drain in the inlet line at its lowest point between the
header and the turbine. Install a throttle valve in the steam line
1
Steam Turbines
1203
27
86-
29-
near the turbine. Close this valve and turn steam into the line
and when hot, check the face of pipe flange with turbine flange.
Make sure that the faces are in line and parallel and that no
force is necessary to bring them together or to match the bolt
holes.
28 83 82 81 80 79 25 22 23 21 18 20 19 17 85 84

20950 DOCOOLT
BALA
BBB
UJU
Aa.ooo
Ca
1
30 31 36 37 32 33 34 87 88 38 89 39
Fig. 42.-DH turbine speed governor. List of parts on page 1199.
How should the exhaust line be installed?
Ans. The exhaust line should have a flexible expansion joint
placed close to the turbine or should otherwise be arranged to
compensate for expansion. Provide a drain at lowest point in
1204
Steam Turbines
this line. Exercise the same care in lining up the pipe flange with
turbine flange as described for the inlet line.
Do not depend upon the sentinel relief valve to protect the turbine
casing against excessive back pressure. It is advisable to install a large
relief valve at some point in the exhaust line. This can be large enough
to protect all equipment which may be exhausting into a common
header.
How about the miscellaneous pipe connections?
Ans. Each packing box has a drain connection in the lower
half. These can be piped separately or in series, but in either case
must exhaust to atmosphere. For condensing turbines there will
be a tapped opening in the upper half for admitting sealing
steam under two or three pounds pressure. Each bearing has a
cartridge type water cooling coil. Inlet opening (1/8 in.) is at
the top and outlet (1/4 in.) at the bottom. These may be piped
separately or in series. Place a valve in the inlet line. Water
pressure should preferably be 25 to 30 lbs. and must never
exceed 100 lbs.
The inlet flange is tapped on the side for bleed-off line. Install a valve
at this point and arrange blow-off to atmosphere. After the over speed
governor valve has closed, either due to over speeding or hand tripping,
close throttle valve in steam line and then open this bleed-off valve to
relieve pressure before attempting to reset over speed trip valve. A
drain connection is provided at the lowest point of the casing. Install
a valve at this point with or without a steam trap.
Operation
What should be done before attempting to start the
turbine?
Ans. Clean off any dirt which might have accumulated dur-
ing erection, flush out bearing cavities and fill with new oil, then
Steam Turbines
1205
work the governor and trip valves by hand to make certain that
they are free.
What should be done when starting for the first time?
Ans. Check alignment after the turbine has become heated.
48-
54
53
Coupling halves must be in line within .004 in. If found to be out
of line, disconnect the inlet and exhaust flanges and re-align. Be sure
39 93 52 92 50 49 47 46 45 91 90 44 41 42 43 17 40

L
How would you start the turbine?
Ans. I would proceed as follows:
1. Check oil level in bearings.
2. Open drain from turbine casing.
71
Fig. 43.-DH turbine over speed emergency governor.
that the flanges of these lines are parallel with the turbine flanges
before reconnecting them.
1206
Steam Turbines
3. Open drains in inlet and exhaust lines.
4. Open exhaust valve.
5. Crack throttle valve.
6. Close drain valves after condensation ceases to flow and turbine
has become heated.
7. Open throttle valve sufficiently to start the turbine.
8. Examine oil rings—make sure they are turning.
9. Open throttle valve gradually until the machine comes up to speed
and the governor has taken control.
10. Open throttle valve wide.
When the operator becomes familiar with the turbine, it may
be brought up to full speed within 30 to 60 seconds.
What important precaution should be taken after start-
ing the turbine?
Ans. Test the over speed trip governor by actually over
speeding the machine.
If not advisable to over speed the driven machine, disconnect the
flexible coupling.
How do you over speed the turbine?
Ans. Push on the top of governor lever (No. 27 fig. 42).
What does this do?
Ans. It opens governor valve, increases supply of steam to
the nozzle, and speeds up the turbine. The over speed governor
should trip at a speed of 10 to 15% above the designed speed
shown on the name plate.
How do you shut down the turbine?
Ans. Proceed as follows:

Steam Turbines
1207
1. Trip the over speed governor valve by disengaging trip latch
No. 46. This will test the valve mechanism.
2. Close throttle valve in steam line.
3. Reset over speed governor.
ve
4. Open all turbine drains.
oi si djant 99% of
INSPECTION WINDOW
OIL DRAIN
OIL LEVEL GAUGE
STEAM SEAL FOR
CONDENSING TURBINE
being chenong bas mes ameya ovlay sit qus
voy hage av at T
OIL FILL
Fig. 44.-Side view of DH turbine.
Mo
Va
goy Boog
pato adsingolo B
lio wit drift her po nam
ho wou jist oms
19
'f
b
&
Lagang.
OIL FILL
WATER INLET
WATER OUTLET
OIL DRAIN
CASING DRAIN
What care should be given to the turbine?
Ans. There are numerous items that should be attended to
such as:
1208
Steam Turbines
1. Watch oil level in bearings.
2. Examine oil at least once each week to make sure that it is in
good condition. Evidences of deterioration are: increase in viscosity,
development of acidity, and the deposit of sludge or sediment.
3. Clean out and flush the oil reservoirs at least every two or three
months. Refill with new oil.
4. Keep the valve stems clean and properly packed.
5. Trip the over speed governor occasionally to see that it is in
proper condition.
6. Watch for endwise movement in the shaft of the driven machine.
Make sure that this movement is not transmitted to the turbine shaft.
7. Inspect the bearings frequently. On sleeve bearing turbines the
governor end bearing is set for .008 in. total clearance between thrust
faces. See that this clearance is maintained. Keep the bearings in good
condition and the turbine will operate indefinitely.
What kind of oil should be used for lubrication?
Ans. In order that the oil rings may carry the oil to the top
of the journals and distribute it freely over the bearing surfaces,
the oil itself must have the proper body under the existing oper-
ating temperatures. It must not be so heavy as to retard the
action of the rings. An oil that is too light, on the other hand,
will not be able to maintain the necessary film between the
surfaces.
As temperature has a positive influence on the body of an oil, it is
necessary that an oil be selected which will attain the proper body at
the operating temperatures to which it will be subjected in actual
service.
How long will the oil last?
Ans. The time that an oil will last in a turbine varies accord-
ing to operating conditions.
The continuous circulation of oil in a bearing results in a gradual
deterioration of the oil itself, due to the action of heat, moisture, and
air,

Steam Turbines
1209
Evidences of this deterioration are: development of acidity, increase
in viscosity and the deposit of sludge or sediment.
The length of service that may be expected from the oil is dependent
upon many variables, such as stability, operating temperature, rate of
circulation, etc. Consequently it is impossible to make any definite
statement in regard to the frequency of oil changes.
Since the quantity of oil required for ring oiled bearings is small,
good advice is to change the oil frequently.
SENTINEL RELIEF
Maintenance
Figs. 41 to 44 show construction of sleeve bearing turbines.
BLEED-OFF
CONNECTION
VALVE
&
HILL
ANDERSON
IND.
DEAN
PUMP
PACKING BOX DRAIN
Fig. 45.-End view of DH turbine.
Co.
BACK PRESSURE
GAUGE CONNECTION
REMOVE BLIND
FLANGE FOR
NOZZLE AND
BLADE
INSPECTION

1210
Steam Turbines
How are the two halves of the casing sealed?
Ans. With Permatex or other liquid gasket such as oil and
graphite. Top half casing is provided with tapped holes for jack
screws which are used to break the joint. There are no high
pressure joints inside this casing.
a
THILL
PUMA
GO
Dow
GOVERNOR PLUNGER
ASSEMBLY
GOVERNOR LEVER
AND BRACKET
Fig. 46.-End view of DH turbine showing accessibility of speed governor.
How is leakage of steam along the shaft prevented?
Ans. By carbon ring packing.
new Hat 563-
Steam Turbines
1211
Each packing box No. 5, consists of a bronze split housing, three
carbon rings, bronze diaphragm No. 72, and cover No. 73. Inner and
outer carbon rings No. 6 are two piece type Center carbon rings No. 6
are two piece type. Center carbon ring No. 6A is four piece self-adjusting
type. Garter springs No. 7 which hold rings together are stainless steel.
How do you renew the carbon rings?
Ans. First remove top half turbine casing, then loosen cover
No. 73 sliding it back along the shaft, then lift off top half of
packing box. This exposes the rings which can easily be removed.
Make certain that the shaft and packing housings are free from rust
or scale.
How do you insert new rings?
Ans. Line them up so that the slots for the retaining pins
No. 74 are at the top and on exact center with the shaft.
What should be done next?
Ans. Replace top half housing using oil and graphite at the
split. Next replace the top half casing and then pull up the cover
No. 73. When the packing box is properly assembled, rings seat-
ing and pins in slots, very little pressure is required to pull up
the cover No. 73. When in proper position there is 1/16 in.
clearance between cover and housing.
If clearance be greater, the pins are riding on the carbon rings, and
it will be necessary to dismantle and re-assemble. Joint of housing
with casing is made with Permatex or oil and graphite. Carbon ring
clearance on shaft is .002 in.
Describe the bearings.
Ans. They are babbitt lined, sleeve type, ring oiled and
horizontally split, mounted in cast iron split brackets.
They may be rocked out of position and replaced after removing
bearing caps. Governor end bearing No. 15 is babbitt faced at both
1212
Steam Turbines
ends and serves as a thrust bearing as well as radial bearing. This
bearing has radial oil grooves in both ends for lubricating the thrust
faces. Running clearance between each thrust face is .004 in. or .008 in.
total for both faces. Coupling end bearing No. 11 has oil collector
grooves in both ends with drain holes in lower half.
What do replacement bearings require?
Ans. Scraping and fitting to the shaft, so that the running
clearance will be .003 to .004 in. Also the governor end bearing
should be scraped on both ends to fit into the space occupied by
the old bearing, but if necessary the locating collar No. 16 which
is set-screwed to shaft, can be shifted either way to match the
new bearing.
What precaution should be taken in fitting the bearings?
Ans. Make certain that the rotor is equidistant between
nozzle No. 56 and reversing nozzle No. 57. Clearance at nozzle
and also reversing nozzle is 1/32 in.
What provision is made on bearing caps?
Ans. Each bearing cap has a tapped opening at the top for
filling the oil reservoir. Through these openings the operator
can view the oil rings to make certain that they are turning
with the shaft.
How is the oil cooled?
Ans. By cartridge type water cooling coils No. 71.
Are they necessary?
Ans. Not always.
What should be done when necessary to renew blades?
Ans. The rotor should be returned to factory for assembly
balance and inspection.
Steam Turbines
1213
What should be done when the rotor cannot be returned
to the factory?
Ans. Order a new wheel complete.
How would you remove a nozzle?
Ans. Unbolt the steam chest assembly. Nozzle stand flange is
then exposed and this assembly slides out of the casing.
How would you replace?
Ans. Dowel pin No. 94 permanently fixes the position of
nozzle and stand with respect to blades. When replacing the
stand, make sure that the nozzle outlet lines up with the blades,
then redowel.
How do you remove over speed valve assembly?
Ans. To remove over speed valve assembly, first disconnect
trip link No. 45, then remove cap screws from valve cage No. 93.
Joint with the steam chest is broken by two jack screws which
are inserted into tapped openings provided for this purpose. The
basket type steam strainer No. 54 is a part of and is removed
with this assembly.
How do you dis-mantle this assembly?
Ans. Remove strainer by taking out two screws. Unscrew
trip steam knob No. 47 and nut No. 49, both right-hand threads.
Lift off spring. Loosen packing nut No. 92. Then push valve
stem No. 48 through packing. Unscrew the recessed pipe plug
from lower end of trip valve No. 53 and push out valve stem.
Reverse this procedure when re-assembling. Clearance between trip
lever No. 44 and governor hub No. 17 is 16 in. Adjust at trip link No. 45.
How do you remove governor valve?
Ans. Take off governor lever bracket No. 28, then loosen cap
1214
Steam Turbines

“RUCOL FUOC
MARAS
UUD
77 98 76 95 68
टं
9 66 97 96 63 64 67 65
Fig. 47.-Section through ball bearing of DH turbine. See accompanying list of parts.
Steam Turbines
1215
PARTS LIST
No.
9 *Bearing Seal Ring
63 *Ball Bearing Cage (Coupling End)
64 *Ball Bearing End Cover
65 *Bearing Seal Ring (Coupling End)
66 *Oil Ring Carrier (Coupling End)
67 *Ball Bearing Lock Nut and Washer (Coupling End)
68 *Ball Bearing Cage (Governor End)
No.
76 *Ball Bearing Lock Nut and Washer
(Governor End)
77 *Oil Ring Carrier (Governor End)
95 *Ball Bearing (Governor End)
96 *Ball Bearing (Coupling End)
97 *Oil Ring (Coupling End)
98 *Oil Ring (Governor End)
screws in flange of steam chest head No. 34. Steam chest head and governor valve
may then be pulled out. This exposes valve cage No. 88 which may also be pulled
out. Pin No. 87 is set for 64 in. clearance at steam chest head No. 34.
How do you remove steam chest assembly?
Ans. Steam chest assembly can be removed as a unit simply by loosening the nuts
which hold it to the casing. On two-nozzle turbines the auxiliary valve stand No. 58
and hand valve No. 59 are a part of and are removed with this assembly.
How do you renew the trip valve packing No. 52?
1216
Steam Turbines
Ans. Unscrew knob No. 47 and nut No. 49 (right-hand
threads) lift off spring No. 50, unscrew packing nut No. 92,
then pull old packing. Replace with packing ordered from the
factory. Work in by pushing stem down by hand. Make certain
that the stem works freely before starting the turbine.
How do you renew governor valve packing No. 33?
Ans. Take off bracket No. 28, unscrew nut No. 31, unbolt
cradle No. 32, then pull old packing. Replace with packing
ordered from the factory. Never fill the box completely full.
After assembling, work the stem by hand to make certain that
it is free. Never use standard square packing. Use only conical
packing.
How do you dismantle speed governor?
Ans. Disconnect bracket No. 28, withdraw governor plunger
No. 23, remove top half governor housing, unscrew governor
nut No. 22 (right-hand thread), then governor spring No. 21
with spring seat No. 20, plunger seat No. 19 and fly balls
No. 18, can be lifted out.
Before unscrewing governor nut, be certain to note its exact position
on the shaft so that it can be replaced in the same location.
To inspect or renew governor plunger No. 23 or ball bearing No. 25,
simply disconnect bracket No. 28 and draw out plunger assembly.
No other parts need be disturbed.
How do you make speed adjustment?
Ans. Speed may be changed while in operation. Turning ad-
justing screw No. 30 to the right reduces speed, turning to left
increases speed.
ĭ
A total adjustment about 20 per cent or approximately 10 per cent
above and below normal may be made in this manner. Additional
speed adjustment of about 5 per cent may be made, after shutting
Steam Turbines
1217
down the turbine, by tightening or loosening governor nut No. 22 on
the end of the shaft. Governor nut is accessible through inspection
window after removing cover No. 78. See fig. 40.
Adjustment for lower speeds down to about 50 per cent below
normal can also be made while in operation, by further tightening the
adjusting screw, but the governor will be inoperative over this range.
Operation of the turbine will be satisfactory provided the load of the
driven machine is fairly constant and the steam pressure does not
fluctuate to any great extent.
How does the over speed governor work when over speed
occurs?
Ans. Plunger No. 42 moves outward, striking lever No. 44,
which releases latch No. 46, permitting spring No. 50 to close
trip valve No. 53.
Do not attempt to reset valve until steam pressure has been relieved.
To relieve pressure, close throttle valve in steam line and open hand
valve which was installed at turbine inlet flange.
How do you raise trip speed?
Ans. Remove inspection cover No. 78, loosen Allen head
screw No. 85, and then tighten nut No. 41. A slight turn of this
nut will increase speed considerably. Be sure to tighten the set
screw after any adjustment.
Check this over speed valve at least once each week by hand tripping.
Simply disengage trip latch No. 46 which allows the valve to close.
Also check trip plunger No. 42 periodically to make certain that it is
free to move outward. This is done by inserting a blunt nosed rod
through the hole in nut No. 40 and pressing down against spring
tension.
Troubles
Here are given a few troubles that may be encountered from
time to time together with probable causes.
1218
Steam Turbines
1. Vibration.
Bent shaft.
Worn bearings.
Coupling out of balance.
Driven machine out of balance.
Mis-alignment between turbine and driven machine-check when
turbine case is hot.
2. Stuffing boxes leaking steam along shaft.
Clogged drain line.
Carbon rings improperly installed.
Worn carbon rings-check and replace if necessary.
Clean and polish shaft surface at same time.
3. Governor hunting.
Worn or bent valve stem.
Worn or fouled governor plunger.
Lost motion in governor lever.
Governor valve sticking.
Governor valve or cage worn.
Worn governor ball bearing.
4. Turbine will not come up to speed.
Speed governor out of adjustment.
Load of driven machine too great.
Nozzle throat fouled by foreign matter.
Low steam pressure at turbine inlet.
Low pressure at nozzle-caused by partially closed valve in steam
line, clogged steam line or strainer.
Check nozzle pressure at tapped opening in top of steam chest
close to turbine case.
Steam Turbines
1219
B- EXHAUST·
DIMENSIONS TYPE DH TURBINES
C
M
1000
WWWAL
·A-INLET
000
R
W
<
RJ
R ST
SIZE A B CDEF
MNOP
TURBINE
104 22 82 11 138 1734
GHIJKL
DH-10 12P.T. 3P.T. 148 98 10 42 152 31 4
DH-20 25 |16|104|143| 5% 23 4% 1
DH-30 3 616101% 141 68 282 48
DH-40 4 10 |19½ 13½ 143% 8% 354 5
138 48 124 124 193 244 418 11
14 16 54 15 14
14 21 |54|182 18
25 30% 418 13 13
33 383 478/74 174
Figs. 48 and 49.-End and side views of Type DH turbines with table of dimensions.
50/10
N
W
る
​72 8 1.249
Fr.
U
1.250 15
T- DIA. HOLES
VWXYZ KEYWAY
416 50 32 22 24 16×32
1.750
1.749 58 72 32 32 24 3x 6
8 1.749 52 10 48 4 24 8×16
8 2499 72 132 44 5 34 zx 4
1


1220
Steam Turbines
A
C
5. Turbine speed too high.
Governor out of adjustment.
Worn governor valve or cage.
6. Bearing failures.
Mis-alignment.
Inferior or improper oil.
Improper fitting or oil grooving.
Thrust transmitted to turbine shaft from driven machine.
Bearing temperatures above 200° are not alarming on sleeve
or ball bearing machines. However, these higher temperatures
require closer attention to oil selection and more frequent oil
changes.
i
Air Compressors
1221
CHAPTER 57 ·
Air Compressors
What is air?
Ans. A gas consisting principally of a mechanical mixture of
23.2 per cent (by weight) of oxygen, 65.5 per cent nitrogen and
1.3 per cent argon.
What is free air?
Ans. Air at atmospheric condition at the point where a com-
pressor is installed?
What is compressed air?
Ans. Air forced into a smaller space than it originally occu-
pied.
What happens when air is compressed?
Ans. Both its pressure and temperature rise.
What is the object of compressing air?
Ans. The power available from compressed air is used in
many applications as a substitute for steam, electricity or other
forces as in operating shop tools, rock drills, etc.
1222
Air Compressors
What happens when the space occupied by a given volume
of air is enlarged?
Ans. The volume of air expands which reduces both its
pressure and temperature.
GAUGE PRESSURE
102.9
1/8 VOLUME
117.6 LBS. L
44.1
14.7
4 VOLUME
58.8 LBS
A
½ VOLUME
29.4 LBS
117.6
L

58.8
A
R
8 VOLUME
R 29.4
→½ VOLUME
F
14 VOLUME
14.7
UNIT VOLUME
ZERO PRESSURE
UNIT VOLUME
14.7 LBS (ATMOSPHERIC PRESSURE)
F
Figs. 1 to 5.-Diagram and compression stroke progressively shown illustrating
Boyle's law. As the piston travels from position F, to R, A, L, the pressures
are 14.7, 29.4, 58.8, 117.6 lbs. absolute, respectively, being inversely pro-
portional to the volume. The points F, R, A, L, on the compression curve
correspond to the piston positions F, R, A, Las shown.
Air Compressors
1223
3r
1
State Boyle's law.
Ans. At constant temperature, the absolute pressure of a gas
varies inversely as its volume.
A
B
E
3r
M
H
FI
ນ
Boyle's Law


Le S
S
น
S
D
M
3
D
F
JM
H
R
R
F
ا
S



H
Figs. 6 to 11.-Compression cycle illustrated by indicator diagrams and ele-
mentary compressor. A, beginning of intake stroke; B, intermediate position
of intake stroke; C, end of intake stroke, note atmospheric intake line LF,
and vacuum line MS; D, intermediate position R, of compression stroke;
E, point of maximum compression, note compression curve FRH; F, end of
cycle, note horizontal discharge line HD, indicating discharge into receiver
at constant pressure.
1224
Air Compressors
What is compression of a gas at constant temperature
called?
Ans. Isothermal compression.
What is the ratio of compression?
Ans. The ratio of the final volume to the initial volume.
Example: If (at constant temperature) the initial volume be 10 per
cent of the final volume, what is the ratio of compression?
final volume ÷ initial volume
100
÷
10
ratio
=
How is the final pressure of compression obtained know-
ing the initial pressure and number of compressions?
Ans. RULE: Final pressure of compression
initial pressure
X number of compressions.
Example: If air be compressed from an initial pressure of 33½ lbs.
per sq. in. absolute to % volume, what is the final pressure?
Here the number of compressions
E
Applying rule
= 1 ÷
final pressure
*
1
3
$
=
= 1 × X
33½ × 3
3
1
=
=
10
3
100 lbs. absolute.
What precaution should be taken in making com-
pression calculations?
Ans. Once and for all remember that the pressures should
be absolute pressures not gauge pressures.
How do you find the initial pressure of compression?
Ans. RULE: Initial pressure of compression final pressure
÷ ratio.
6.
Air Compressors
1225
•
ť
I
i
!
Example: If the final pressure of compression be 100 lbs. per sq. in.
absolute, and the number of compressions or ratio be three, what is
the initial pressure absolute.
Applying the rule
initial pressure
=
100 ÷ 3
Final pressure
Initial pressure
WORK
HEAT
@
Fig. 12.-A familiar example of the heat of compression.
33½ lbs. absolute.

OF COMPRESSION
KREKORONAV
нот
PUMP
Summary
÷
Compression ratio = initial volume final volume.
initial pressure X compression ratio.
final pressure
÷ compression ratio.
.
I
1226
Air Compressors
State Charles' law.
Ans. At constant pressure the volume of a gas is proportional
to its absolute temperature; at constant volume the pressure
is proportional to its absolute temperature.
and a paved parade As
Charles' Law
What happens when air is compressed?
Ans. Heat is generated as illustrated by the familiar opera-
tion of pumping up a bicycle or automobile tire.
A·
B-

VOL
UNITY VOLUME
Fig. 13.-Elementary air compressor illustrating the phenomenon of com-
pression as stated in Boyle's and Charles' laws and explained in the
accompanying text.
What is the big problem in the design of compressors?
Ans. To get rid of the heat of compression which results in
a loss by boosting the pressure abnormally.
What is compression without receiving or giving up heat
called?
Ans. Adiabatic compression.
+
Air Compressors
1227
-VOLUME COLD
VOLUME HOT
ADIABATIC LINE.
Boyle's and Charles' Laws
(Combined)
In the ordinary process of air compression, what two
elements are at work toward the production of a higher
temperature?
ť
SEEN I
ť't'
ISOTHERMAL LINE
HLANAD
LOSS DUE TO
·HEAT OF COMPRESSION
A
ADIABATIC, LINE_
HID
!
200-120.
租
​77
Figs. 14 to 17.-Diagrams and elementary compressors illustrating loss due to
heat of compression. If no means be provided to carry off this heat, compres-
sion will be adiabatic as indicated by the curve ' fig. 14. Assuming all the
heat to be carried off by the water jacket (fig. 17) compression will be isother-
mal as indicated by the curve H" fig. 16. Here both curves are shown, the
shaded area representing loss. Hence in compressor construction provision is
made to carry off as much of the heat of compression as possible.
ī

Ans. 1, The reduction of volume by the advancing piston;
and 2, the increasing temperature due to the increasing pressure
corresponding to the reduced volume.
Describe the application of the two laws.
1228
Air Compressors
Ans. For example, if a cylinder be filled with air at atmos-
pheric pressure (14.7 lbs. per sq. in. absolute) and then the
piston be moved to compress the air to say 1 volume. Then
according to Boyle's law the pressure will be trebled or =
14.7 X 3 44.1 lbs. absolute. In reality, here is where Charles'
law comes in, a pressure gauge on the cylinder would show at
this time a pressure greater than 44.1 lbs. absolute because of
the increase in temperature produced in compressing the air.
ACTUAL
ť"

t'"'
τ
ť
SOTHERMAL
IN PRACTICE
CURVES EXAGGERATED
FOR EMPHASIS
ADIABATIC
LOSS SAVED
(SOLID BLACK)
LOSS NOT SAVED
(IN SEGTION)
Fig. 18.-Isothermal, adiabatic and actual compression curves showing position
of the loss due to the heat of compression not saved, and saved.
This is called adiabatic compression and extra work is required
of the piston to overcome the excess pressure due to rise of
temperature.
Why is this extra work lost?
Ans. Because after the hot compressed air leaves the cylinder
it cools and the pressure drops to what it would have been if
Air Compressors
1229
compressed at constant temperature, that is, according to
Boyle's law.
Is all the extra work lost in the operation of a com-
pressor? Why?
Ans. No, because in compressors where working efficiency
is considered, some means of cooling the cylinder is provided
such as projecting fins or jackets for the circulation of cooling
water.
How much work is lost?
Ans. About half, more or less depending upon the design of
the compressor.
What is a compressor?
Ans. A machine (driven by any "prime mover") which com-
presses air into a receiver to be used at a greater or less distance.
What is a prime mover?
Ans. An apparatus or mechanism whereby motion and force
are received directly from some natural source of energy and
transmitted into some form of motion by means of which the
power may be conveniently applied.
Name some prime movers.
Ans. Steam engines, gas engines, electric motors, etc.
Mention some different types of compressors.
Ans. 1, single acting; 2, double acting; 3, single stage;
4, double stage; 5, air cooled; 6, water cooled; 7, single clyinder;
8, multi-cylinder, etc., etc.,
What is a single acting compressor?
1230
Air Compressors
Ans. One in which compression takes place every other
stroke.

SINGLE
ACTING
||!!!
FEATHER
WEIGHT
VALVES
DOUBLE
ACTING
||||||---|
[…]
ADMISSION
DISCHARGE
Figs. 19 and 20.-Compressors 1. Fig. 19, single acting; fig. 20, double acting.
What is a double acting compressor?
Ans. One in which compression occurs every stroke.
What is a single stage compressor ?
Ans. One in which the compression cycle takes place in a
single cylinder.
Air Compressors
1231
What is a two stage compressor?
Ans. One in which the compression begins in one cylinder
and is completed in a second cylinder.
What is the object of two stage compression?
Ans. It divides the temperature range between the two cyl-
inders and permits cooling between the cylinders.
SINGLE STAGE



ADMISSION
Fig. 21.-Compressors 2. Single stage.
DISCHARGE
What is a reciprocating compressor?
Ans. One having a piston arranged to move to and fro, that
is, forward and backward.
1232
Air Compressors
What is the proper name for a centrifugal compressor?
Ans. A blower.
What is a rotary compressor?
Ans. One having a vane rotor or its equivalent mounted
eccentrically in a stationary casing.
TWO STAGE

LOW PRESSURE
CYLINDER
INTER - COOLER
DISCHARGE TO INTER COOLER
ADMISSION TO H. P. CYL.
¿
ADMISSION
Fig. 22.-Compressors 3. Two-stage.
HIGH PRESSURE
DISCHARGE
CYLINDER
What is a direct connected compressor?
Ans. One in which the prime mover is attached direct to
the compressor without any interposed transmission such as
chain, belt, etc.
What is the difference between vertical, horizontal and
V cylinder placements?
Air Compressors
1233
Ans. This relates to the position of the cylinder or cylinders
axes with respect to the horizontal.
What is the point about single cylinder and multi-
cylinder compressors?
Ans. This relates to the power end. Where a steam engine
is the prime mover one cylinder (or two if compound) does the
job. Of course when a gas engine or Diesel engine is the prime
CENTRIFUGAL
ROTARY


Figs. 23 and 24.—Compressors 4. Fig. 23, centrifugal; fig. 24, rotary.
mover, owing to its outstanding inherent defect as compared.
with a steam engine, multi-cylinders are necessary, three, four,
six and even eight are required to approach the performance
of a steam engine.
What is the point as to compound steam engine drive?
Ans. It is not a case of getting a smoother turning effect, but
to get better economy.
What is a water cooled compressor?
1234
Air Compressors
1
Ans. A misnomer for a compressor whose cylinder is water
jacketed and through which flows a current of cold water.
What duty is performed by the cold water?
Ans. It functions as a transmission medium to carry off some
of the heat of compression.
LOW PRESSURE MEDIUM PRESSURE


CENTRIFUGAL
SINGLE STAGE
HIGH PRESSURE

TWO STAGE
Figs. 25 to 27.—Compressors 5. Fig. 25, low pressure; fig. 26, medium pressure;
fig. 27, high pressure.
What other medium is employed to carry off the heat of
compression?
Air Compressors
1235
AIR
Ans. Air.
How is the cylinder constructed for air cooling?
Ans. It has cast integral numerous thin fins to form excess
cooling surface exposed to a draught of cool air which forms
the medium to carry off some of the heat of compression.
DIRECT CONNECTED

CYLINDER
STEAM
CYLINDER
POWER DRIVEN

O
Figs. 28 and 29.-Compressors 6. Fig. 28, direct connected; fig. 29, so called
'power" driven.
PRIME MOVER
What is a power driven compressor?
Ans. A ridiculous term (they are all power driven) for a
compressor whose prime mover is a separate unit and connected
by a transmission such as belt, chain, etc.
It is known as such and nothing can be done about it.
1236
Air Compressors
What are "en bloc" or uni-bloc cylinders?
Ans. Two or more cylinders cast integral, that is, all in one
casting.
Describe the hopper cooling system.
SINGLE CYLINDER

AIR
CYLINDER
SINGLE
STEAM-
CYLINDER
MULTI-CYLINDER
AIR COMPRESSOR
ē

'GAS ENGINE
(DIRECT CONNECTED)
Figs. 30 and 31.-Compressors 7. Fig. 30, single cylinder; fig. 31, multi-
cylinder.
Ans. This is a non (external) circulating system. The cylinder
has an open water jacket of considerable volume. It is filled
with water and the volume of water depended upon to cool.
the cylinder by thermo circulation.
What type of valves are used on compressor cylinders?
Air Compressors
1237

AIR
COMPRESSOR
COMPOUND
H.P.
CYLINDER
Fig. 32.-Compressors 8. Compound.
L.P.
CYLINDER
Q
Ĉ
Ans. The various types of air valve in general use may be classed as: 1, finger;
2, feather; 3, plate; 4, ring (a, plain; b, dual cushion); 5, channel.
What is a feather valve?
What are finger valves?
Ans. Valves made of narrow strips of stainless steel fastened to a seat at one end
and free to flex along their length.
What is the application of finger valves?
Ans. They are suitable for light service as in small units for garage and service
stations.
1238
Air Compressors
L
Ans. A strip of ribbon steel which covers a slightly narrower
slot when the valve is closed.
How does it work?
Ans. In opening, the feather valve flexes against a curved
WATER COOLED


WATER
WATER JACKET
Fig. 33.-Compressors 9. Water cooled.
guard allowing the air to pass on either side of the valve strip
with but very little friction.
Describe the operation of the feather valve?
Air Compressors
1239
Ans. When opening, the valve makes contact along the
curved surface of the guard instead of a direct impact.
What is a plate valve?
Ans. This valve (also known as the Rogler valve) has a stop
plate. Valves of this type consist of flat discs of special steel,
clamped upon valve seats and held in position by spring arms
AIR COOLED

↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓
FINS
Fig. 34.-Compressors 10. Air cooled.
А
*.
formed in one piece with the valve itself. The stop plate has
spring arms which press upon the valve, limiting the opening
movement and closing the valve at the end of the stroke. The
stop plate is backed up by a buffer plate which is identical with
the stop plate except that the spring arms are not cut through.
What is a ring disc valve?
Ans. The valve proper consists of annular rings stamped out
1240
Air Compressors
of thin alloy steel. One type of valve of this class is cushioned
by special springs.
What is a channel valve?
Ans. This is a heavy service valve. It consists of: 1, cover;
2, valve spring; 3, channel valve; and 4, valve seat.

VALVE SEAT
VALVE
VALVE SPRING-
REACTION PLATE-
VALVE GUARD
VALVE SEAT
VALVE
VALVE SPRING
REACTION PLATE
VALVE GUARD-
VALVE SEAT
VALVE
VALVE SPRING
REACTION PLATE.
VALVE GUARD
///////// 0 /// 0 /// 0 /// 0 /// 0 //
X

/// 0 /// 0 /// ✪ /// ℗ /// 0 /// 0 //

10///// 0 /// 0 /// 0 /// 0 /// 0 ///
1
Figs. 35 to 37.-Diagrams showing operation of the ring disc valve with dual
cushion springs.
What is the construction of the compressor frame?
Ans. This part of the compressor is of ample proportions
with metal properly distributed to secure the maximum strength
and rigidity. There are numerous types of frame depending
upon the type of compressor.
How about the various other parts of the compressor?
Air Compressors
1241
*
IST STROKE
3RD STROKE
2ND STROKE



TWO STAGE
THREE STROKE
Figs. 38 to 40.-The two stage three stroke cycle, showing events of each stroke.
1242
Air Compressors
L.P.AIR
VER-COOLER
M
H.P. AIRI
H.P. STEAM
L.P. STEAM.
Fig. 41. Horizontal tandem two stage compressor with direct connected compound steam end. In operation
the final temperature in each cylinder will be the same if the work has been divided equally and the inter
cooler properly designed. It will be very much lower than it would be if the compression were done in one
cylinder. For instance, in compressing air to 100 lbs. pressure in a two stage compressor, the air is com-
pressed from atmospheric pressure to say 26½ lbs. in the low pressure cylinder and is delivered to the inter
cooler at this pressure and at 240° Fahr. (atmospheric temperature at 60° Fahr.). If all of the heat of com-
pression be taken out of the inter cooler, it is admitted to the high pressure cylinder at atmospheric temperature
and is there compressed from 26½ lbs. to 100 lbs. and delivered to the receiver at 240° Fahr. In a single
stage compressor the air is compressed from atmospheric pressure to 100 lbs. in one cylinder and reaches
the receiver at 480° Fahr.

Ans. They, especially the moving parts, follow in general steam engine design.
What is the advantage of a duplex machine?
↑
Air Compressors
1243
INSPECTION
PLATE
OIL
GAUGE
BEARING
LARGE OIL
DIPPERS
CONNECTING ROD
MECHANICAL
LUBRICATOR
TAPERED ROLLER
MAIN BEARING
COUNTER BALANCED
CRANK SHAFT
OIL WIPER
RINGS
ADJUSTABLE
SLIPPER TYPE
CROSSHEAD
INTERCOOLER
PISTON
ROD
COLLAR
How are they timed?
Ans. The two crank pins are set at 90°,
SNAP 'PISTON
RINGS
FLOOR LEVEL
STUFFING BOX
L.P. VALVE
SOLE
PLATE
SEPARATOR
H.P. VALVE
LIBERAL WATER
JACKETS
Fig. 42.-Horizontal tandem two-stage water-cooled belt-driven compressor. Sectional view with names of
parts. The illustration shows the inter-cooler connecting the two cylinders.
Ans. By properly timing the events of the two pairs of cylinders, the load is
equalized to a considerable extent.

1244
Air Compressors
INSPECTION
PLATE
OIL GAUGE-
BEARING
LARGE CIL
DIPPER
CONNECTING ROD
-MECHANICAL
LUBRICATOR
TAPERED ROLLER
MAIN BEARING
COUNTER BALANCED
CRANK SHAFT
OIL WIPER
RINGS
SEPARATOR
CROSSHEAD
FLOOR
INTERCOOLER
PISTON ROD
COLLAR
PISTON
RINGS.
SECOND STAGE
VALVE
LEVEL
L.P. FEATHER
VALVE
H.P. FLOATING
PLUNGER
INTERMEDIATE COIL
TYPE COOLER
WATER
JACKETS
-SUCTION
SOLE
PLATE
DAMOND
·RING PACKING
CYLINDER AND HEAD
-H. P. VALVE
FINAL
DISCHARGE
RELIEF
VALVE
Fig. 43.—Horizontal tandem three-stage (step piston) water-cooled belt-driven compressor. Sectional view
with names of parts.
I

Air Compressors
1245
180
A
ATMOSPHERIC
LINE
ZERO LINE
.00
B
Ć
4' 90°
D′ 180°
B
PHASE DIFFERENCE
90
B'
CRANK
A
CRANK
B
****
Fig. 44.—Diagram showing steam and air simultaneous distribution in duplex compressor with 90°
sequence of cranks.

1246
Air Compressors
What advantage is obtained in operation?
Ans. The 90° "phase difference" in the two air cycles make
it possible to run at lower speeds.
What other advantage is obtained?
Ans. It makes it possible to expand steam to a greater
degree (shorter cut off) and secure the economy corresponding
to the increased ratio of expansion.
What is the disadvantage of the duplex type?
Ans. Increased cost of construction and installation and
upkeep due to the greater number of parts. Moreover friction
is greater.
What other method is employed to obtain a 90° phase
difference?
Ans. The cylinders may be placed at 90°.
Inter and After Coolers
1247
CHAPTER 58
Inter Coolers and
After Coolers
1. Inter Coolers
What is an inter-cooler?
Ans. A species of surface condenser placed between the two
cylinders of a two stage compressor so that the heat of com-
pression generated in the first stage cylinder may be removed (in
part or whole) from the air as it passes through the inter-cooler to
the second stage cylinder.
Why is this necessary for efficiency?
Ans. Because the pressure of a gas increases with rise in tem-
perature (previously explained) and this excess pressure results
in a waste of power in compressing the gas.
What is the approximate saving?
Ans. Roughly each 10° Fahr. decrease in temperature be-
tween stages results in 1 per cent saving in power output.
Mention another favorable result obtained by inter-
cooling between stages.
1248
Inter and After Coolers
JACKET WATER
DISCHARGE
AFTER COOLER
WATER DISCHARGE
B
A
H.P
INTERCOOLER
BAFFLE PLATES
CYL
..P
CYL
20
SECOND STAGE
FIRST STAGE)
GAUGE
AFTER COOLER
E
CIRCULATING WATER DISCHARGE
DISCHARGE
SEPARATOR
yoặc{1:L!
CIRCULATING
PUMP
SUCTION
G
GAUGE
SAFETY VALVE
H.
UMING
OUTLET TO ENERGY CONSUMING
DEVICES
RECEIVER
DRAIN
DRAIN
CONDENSATION
Fig. 1.-Elementary compound or two-stage air compressor showing all the auxiliary apparatus essential for
maximum efficiency in two-stage compression. In operation, free air is compressed in the low pressure of
first stage cylinder to a moderate pressure and discharged at A, into the inter-cooler where the heat of
compression is carried away by the cooling or circulating water which flows from the circulating
pump through the inter-cooler cooling tubes. In this passage short circuiting is prevented by the series or
baffle plates. Passing out of the inter-cooler at B, the air at moderate pressure enters the high pressure or
second stage cylinder and is then compressed to high pressure being discharged at C, into the after-cooler
at D, wherein the heat of the second stage compressor is abstracted in precisely the same way as in the
inter-cooler, the circulating water connection being clearly shown. The highly compressed air now leaves
the after-cooler at E, and passes to the separator. Thus freed of any condensate, the dry air leaves the
separator at F, and enters the receiver at G, wherein it is stored at the working pressure and is discharged
through the outlet H, to perform various kinds of work such as driving rock drills, engines, etc.

Inter and After Coolers
1249
Ans. Since it reduces the maximum temperature in the second
stage cylinder, better cylinder lubrication is obtained which
minimizes valve troubles.
What objectionable action is brought about by inter-
cooling?
Ans. Inter-cooling (or any cooling) causes condensation of
some of the moisture passing through the inter-cooler.
How is the condensate disposed of?
Ans. A separator with float valve ejector is provided to get
rid of the condensate.
What would happen if the condensate passed into the
second stage high pressure cylinder?
Ans. It would wash away lubrication and induce rapid wear.
What should be noted about temperatures?
Ans. The final temperature in each cylinder will be the same
if the work has been equally divided and the inter-cooler
properly designed.
The final temperature will be much lower than it would be if the
total compression were done in one cylinder (single stage).
What difficulties are encountered in an attempt to cool
the air in the cylinder during compression?
Ans. There is not sufficient time during the stroke to thor-
oughly cool the air by any available means.
That is, the old method of injecting cooling water in the cylinder
(wet compression) is out.

1250
Inter and After Coolers
Pass
M6
Outlet
Home
Moisture Separator
Chamber
Battle
Arrangement
Mult-Water
Pass
Fig. 2.-Typical inter-cooler. It consists of a nest of Admiralty metal tubes expanded into corrosion resistant
tube plates at each end. Baffles effectively direct the air or gas across the tubes many times. The entire nest
of tubes may be withdrawn as a unit for cleaning.
Water Outlet
Water Inlet
What should be inferred about compressors whose indicator diagrams show
compression lines "running away" (that is lower) from the adiabatic?
Ans. Such lines should be regarded with suspicion as they probably result from
leakage rather than from efficient cooling.
Such leaks will explain many isothermal compression lines.
Inter and After Coolers
1251
POUNDS OF MOISTURE PER 1000 CU.FT. OF SATURATED
FREE AIR OR GAS AT 14,7LB. ABS. AND TEMP. SHOWN
Describe the construction of a typical inter-cooler.
Ans. It consists of a nest of special metal tubes expanded
into corrosion resistant tube plates at each end. Baffles effec-
tively direct the air or gas across the tubes many times, thus
1.2
1.1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
Ooo
수​수수
​O
3.76 AT
4.92 AT O

32
MOISTURE REMAINING IN SATURATED
AIR OR GAS'WHEN COMPRESSED TO
ANY PRESSURE AND COOLED TO
TEMPERATURE SHOWN.
24723
O
O .20 40 60 · 80 100 120 140 160 180 200 220 240 260 280 300 320
PRESSURE - LBS. PER SQ.IN. GAĠE
Fig. 3.—Air moisture chart. See accompanying text "After Cooling Principles".
affording perfect contact with the cool tubes. The entire nest
of tubes may be withdrawn as a unit for cleaning. Provision.
is made for tube expansion.
What stabilizing effect has the inter-cooler?
Ans. The large receiver volume formed by the inter-cooler
1252
Inter and After Coolers
and the connecting piping, results in a nearly uniform dis-
charge pressure from the low pressure cylinder.
How are inter-coolers mounted?
Ans. Compressors of 1200 cu. ft. capacity and larger have
their inter-coolers mounted directly over the air cylinders. The
inter-coolers of smaller machines are usually arranged under-
neath the cylinders.
2. After Coolers
What is an after-cooler?
Ans. A species of surface condenser in which compressed air
is cooled after compression.
Explain principles relating to after-cooling.
Ans. All free air and all manufactured gas contain varying
amounts of moisture in the form of water vapor. The tem-
perature and volume, and not the pressure determine the
moisture capacity of air or gas. This capacity increases as the
temperature rises. Air under certain conditions can contain a
very appreciable amount of water.
Accordingly great quantities of water are taken into compressors.
At high compression temperature, the air or gas that leaves the com-
pressor can carry this moisture in the form of vapor despite the reduc-
tion in volume. After this compressed air cools in the pipe line to
atmospheric temperature, condensation takes place, resulting in a lot
of liquid in the pipe line which is objectionable.
Describe the construction of a typical after-cooler.
Ans. When water is used as the cooling medium, air may
flow: 1, through the tubes; or, 2, outside the tubes. In the first

Inter and After Coolers
1253
TUBES AND
TUBE SHEETS
BAFFLE PLATES
TUBE NESTS
GAS OUTLET
Fig. 4-Two stage after cooler.
CONDENSATE SEPARATOR
WATER PIPING.
WATER HEAD

1254
Inter and After Coolers
type air passes through numerous tubes, being divided into
thin streams. Proper air velocities are developed for high heat
transfer to the surrounding water.
What is placed at the end of the after-cooler?
Ans. A separator which catches the condensate.
Fig. 5.-Exterior view of after-cooler. It consists of an arrangement of double
coil, copper tubes, one inside another. Water is circulated through the outside
tube, and the compressed air passes through the center tube in the opposite
direction. These after-coolers are suited for tank mounted compressors as in
fig. 16.
How are pipe lines affected by moisture?
Ans. Moisture has various harmful effects in pipe lines. It:
1, produces water hammer; 2, reduces the carrying capacity;
3, causes loss of power by accumulation at low points; and
4, may freeze pipe lines in cold weather.

Inter and After Coolers
1255
What bad effect is encountered in pipe lines in the
absence of an after-cooler?
Ans. Where hot air is passed directly from the compressor
into pipe lines, the heat causes the lines to expand; this is
followed by contraction when the compressor is shut down.
AVISON # To Ogiate/the y
The repetition of this cycle induces leaky joints and consequent air
losses even when expansion joints are provided.
WORTHINGTON
Fig. 6.-After cooler on tank mounted compressor.
How do separators separate the condensate?
Ans. The action depends upon centrifugal force which is
brought into effect by suddenly changing the direction of flow
of the gases usually through 180°.
1256
Inter and After Coolers
Air discharged from compressor at 360° F.
Contains 29.67 lbs. (3.56 gals.) of water vapor per hr.
ES-1 COMPRESSOR
450 c.f.m. Actual Free Air Delivery at
100 lbs. per sq. in. pressure.
RECEIVER
இ
Compressor Inlet Air at 80° F., 70% relative humidity. 27,000 cu. ft.
per hr. carries 29.67 lbs. (3.56 gals.) of water vapor per hr.
Fig. 7.-Example 1. Compressor installation without after-cooler.
29.67 lbs. (3.56 gals.) of water vapor
per hr. at the Receiver.
Receiver and pipe line temperatures are
below 360° F. Thus cooling and con-
densation start immediately in both.
CONCLUSION:-
Practically all of the original 29.67 lbs.
(3.65 gals.) of water vapor per hr.
passes into the pipe line and tools.
What is the object of a receiver?
Ans. To provide a storage reservoir for the compressed air which gives a supply to
work on, thus avoiding sudden pressure fluctuations on load demands.
Mention another advantage of a receiver.

Inter and After Coolers
1257
Air discharged from compressor at 360° F.
Contains 29.67 lbs. (3.56 qals.) of water vapor per hr.
28-PL-12 Aftercooler
ES-1 COMPRESSOR
450 c.f.m. Actual Free Air Delivery at
100 lbs. per sq. in. pressure.
Cooling water
out
Cooling water in
IZZI
CONDENSATE
TRAP
RECEIVER
Compressor Inlet Air at 80° F., 70% relative humidity. 27,000 cu. ft.
per hr. carries 29.67 lbs. (3.56 gals.) of water vapor per hr.
Fig. 8.-Example 2. Compressor installation with after-cooler.
81% of the original water vapor or
2.88 gals. per hr. has been condensed
by the aftercooler. Discharge air,
cooled to 80° F., now contains only
5.67 lbs. (0.68 gals.) water vapor per
hr.
80° F. Air at the Receiver and in the
pipe lines contains 5.67 lbs. (0.68 gals.)
water vapor per hr., but the tempera-
ture is normally below the pipe line
temperature, therefore there is no fur-
ther condensation.
CONCLUSION:-
Only 19% of the original water vapor
(0.68 gals. per hr.) remains in the air
to pass into pipe lines & tools, with
practically no further condensation.
Ans. It insures maintenance of efficient air pressure when momentary demands
are excessive.

When is a large receiver capacity recommended?
Ans. When automatic start and stop control is used on the compressor.
1258
Inter and After Coolers
After-Cooling Principles.—All free air and all manufac-
tured gas contain varying amounts of moisture in the form of
water vapor. The temperature and volume, and not the
pressure, determine the moisture capacity of air or gas. This
capacity increases as the temperature rises.
For example, at 80° Fahr., 1000 cu. ft. of saturated air, i.e., air of
100 per cent relative humidity, will contain 1.57 lbs. of moisture. At
100° Fahr., it will contain 2.85 lbs. One gallon of water weighs 8.33 lbs.
Thus, it is apparent that air can contain a very appreciable amount of
water.
From the foregoing, it is evident that great quantities of water are
taken into compressors. At the higher temperature developed during
compression, the air or gas that leaves the compressor can carry this
moisture in the form of vapor, despite the reduction in volume. How-
ever, after this compressed air or gas becomes cooled in the pipe line
to atmospheric temperature it will hold only a small percentage of this
moisture in the form of water vapor, the balance appearing in the
liquid state.
Example: Saturated air at 80° at compressor intake (0 lb. gauge)
contains 1.57 lbs. of moisture per 1000 cu. ft. Compressed to 100 lbs.
and cooled to 80° with 65° water, the air holds only 0.20 lbs. per 1000
cu. ft. or 13 per cent of the water vapor originally taken into the
compressor. The rest has been condensed in the inter-cooler (if used)
and the after-cooler. On this basis for a compressor of 1000 cu. ft. per
min. capacity nearly 10 gallons of water per hour will be condensed.
The advantages of after cooling are therefore evident.
Air cooled to within 15° Fahr. of incoming cooling water temperature
is considered good practice. Any attempt to secure a lower air tempera-
ture (with the same water temperature) requires a much larger and
more expensive cooler, and increases water consumption. These dis-
advantages more than offset the gain in extra condensation.
For example, note that 87 per cent of the original moisture has been
removed by cooling the air back to 80° Fahr. If the air had been cooled
to 70° Fahr. instead of 80° Fahr., about 92 per cent of the original
moisture would condense, a gain of only 5 per cent in the total
condensate.
Compressor Control Devices 1259
CHAPTER 59
Compressor Control
Devices
Why is some method of control necessary for a com-
pressor?
Ans. So that the compressor can maintain a supply of air
at pre-determined pressure in the receiver to meet any demand.
Name two general control methods.
Ans. Regulation may be secured by providing suitable de-
vices: 1, at the air ends; or 2, at the power ends.
What kind of regulating devices are used at the power
end of steam driven compressors?
Ans. Throttling or variable cut off governors.
What is the peculiarity of these governors for air com-
pressors compared with other service?
Ans. Although the usual function of a governor on a steam
engine is to maintain a constant speed, however, as applied to
a compressor, it acts to maintain a pre-determined constant
pressure by varying the speed of the machine.
1260
Compressor Control Devices
D
}
What is the actuating force for these governors?
Ans. The pressure of the air in the receiver by acting upon
a diaphragm or piston and with proper connection operates the
governor: 1, to vary the amount of steam admitted to the
cylinder as in the case of the throttling governor; or 2, to vary
the cut off of the cut off engine. This acts to increase or

BOILER PRESSURE
-CONSTANT CUT OFF
PARTLY CLOSED THROTTLE. ÁDMISSION
(LIGHT LOAD
V Z Z Z
BOILER PRESSURE
FULL THROTTLE ADMISSION
(HEAVY LOAD)
Fig. 1.—Indicator diagram showing action of throttling governor.

EARLY CUT OFF · LIGHT LOAD
·LATE CUT OFF HEAVY LOAD
·
Fig. 2.-Indicator diagram illustrating regulation by variable cut off.
, Anggun te
Compressor Control Devices
1261
•
:
decrease the speed according as the variation in cut off in-
creases or decreases the m.e.p. respectively.
How does the cut off governor operate to facilitate
starting?
Ans. It is necessary to lengthen the cut off and thus obtain
the necessary torque for starting. It automatically adjusts the
cut off for starting, then returns it to the proper operating
position as soon as the machine is up to speed.
What provision is made to prevent over speeding?
Ans. In case of damage to the governor, over speeding is
prevented by an independent safety stop valve.
When is the automatic "stop and start" method of
control used?
Ans. When the demand for air is intermittent.
Explain the stop and start method.
Ans. The compressor either operates at full capacity or is
shut down, the motor being automatically started and stopped
by a pressure switch.
When no air is being used the compressor is at a standstill and
consumes no power.
What important device operates as the compressor slows
down?
Ans. A regulator unloads the cylinder and shuts off the
cooling water.
How long is this condition maintained?
1262
Compressor Control Devices
B
A
()
C
D
Unloader Operation
NORMAL
PRESSURE
B
RECEIVER
INLET OPEN
INCOMING AIR
Figs. 3 and 4.—Elementary free air inlet unloader showing operation of the
automatic control valve. Fig. 3, inlet open; fig. 4, inlet closed.
CLEARANCE
ATMOS.
HIGH
PRESSURE


A
DIFERUM
INLET CLOSED
AIR SHUT OFF

A
Figs. 5 and 6.-Diagrams corresponding to operation in figs. 3 and 4 as
explained in the text.
Compressor Control Devices
1263
Ans. Until the motor is started and again running at full
speed.
This results in a saving in electric current and cooling water.
What is dual control?
Ans. A combination of constant speed and automatic start
and stop control.
What does it provide?
Ans. A constant speed control where there is steady and
large demand for air or gas and permits switching to automatic
start and stop control during periods of intermittent or small
demand.
What is a free air unloader?
Ans. An automatic device that varies the amount or air or gas
being pumped.
How does it work?
Ans. If the pressure in the receiver build up, due to the
compressor supplying air when none is being used, a relief
valve must blow, thereby resulting in a loss of air, and con-
sequently of power.
Name the various methods of unloading.
Ans. 1, Inlet line unloading valve; 2, inlet and discharge un-
loader; 3, inlet valve kept closed; 4, inlet valve kept open;
5, discharge valve kept open; 6, adjustable compression stroke;
7, variable clearance volume.
What is the application of unloaders on constant speed
compressors?

1264
Compressor Control Devices
Ans. Constant speed compressors require some form of un-
loading device which will permit the driving unit to run at full
speed without delivery of more air or gas then is required.
For what service are unloaders used in addition to their
regular function?
T
A
B
C
M
4240
H
bei fod //
Jument
2090007
-D
G
ob Tit
EA
F
hnu Pinte
.bmums
el te
K
Fig. 7.-Channel valve free air unloader assembled in cylinder. The free air
unloader assembly includes the inlet valve complete. The inlet valve complete
is bolted to the unloader body and can easily be removed for inspection or
replacement after the unloader assembly has been removed from the cylinder.
When re-assembling a valve to the unloader where used, be sure the valve
center bolt nut is locked, and that the pusher B, and spring C, are in place.
If it become necessary to replace a spring C, always use one of the same
size and having the same compression as the one originally furnished.
NOTE. In fig. 7 when air is admitted to the under side of the diaphragm E, through the
hollow inlet cover set screw K, the fingers on the valve pusher, passing through the valve
seat ports, raise the inlet valve off its seat until the pressure under the diaphragm is re-
leased. When inlet valves are held off their seats the air or gas cylinder is vented to the inlet
passage, the air or gas passing alternately in and out of the cylinder without being com-
pressed. The valve cover G, has a machined recess into which fits the inner cover F, of the
unloader assembly. Thus when the unloader assembly is being put into the bottom of a
cylinder, unscrew valve cover set screw K, and set the whole assembly in the outer cover G,
so that inner cover F, fits into outer cover. Place valve seat gasket L, on the valve seat and
cover gasket M, on the cover, and carefully raise the outer cover G, with the unloader
assembly into position. After the valve seat and cover find their fits in the cylinder, insert
and tighten the valve cover tap bolts. Now screw up on the valve cover set screw K, forcing
the valve seat A, solidly onto its gasket, and then lock the set screw in position by means
of the lock nut J.
Compressor Control Devices
1265
AUXILIARY
VALVE
COMPRESSOR
INTAKE FROM
OUTSIDE OF
BUILDING
ㅠㅠ
​PL- AFTERCOOLER
WITH SEPARATOR
REGULATOR
PIPE
MOTOR
SAFETY
VALVE
ES-COMPRESSOR
Fig. 8.-Diagram showing the piping arrangement for constant speed regulation.
RECEIVER
PRESSURE
GAGE
RECEVER
INLET
RECEIVER
DISCHARGE
RECEIVER
DRAIN
Ans. To facilitate starting a compressor, permitting temporary operation without
doing the full amount of work at the start.
With what kind of drive is this especially important and why?

1266
Compressor Control Devices
Ans. With certain types of electric motor that fail to develop
full torque until full speed is reached.
What is an inlet line unloader?
Ans. An unloader that automatically opens and closes the
inlet line under pressure variations in the receivers.

PIPE 70
RECEIVER
EXHAUST
60290
L-MOVE HANDLE TO VERTICAL
POSITION. BEFORE STARTING
COMPRESSOR AGAINST LOAD.
AFTER COMPRESSOR IS UP TO
SPEED MOVE HANDLE TO
HORIZONTAL POSITION.
Fig. 9.-Arrangement of regulator piping for gas compressors with by-pass for
unloading when starting.
Compressor Control Devices
1267

PRESSURE
CLEARANCE
30%
4
312
A
VOLUME
PRESSURE
E D C в
F
LL
3
2
G
VOLUME
H
Fig. 10.-Diagrams illustrating variable clearance. Curve 1 indicates compression adiabatically without any
clearance. All the air compressed is discharged and there is no re-expansion line other than the vertical line 1
indicating a direct drop to atmospheric pressure. Curve 2 shows the compression curve with 10% clearance as
do Curves 3 and 4 for 20% and 30% respectively. With the increase in clearance volume, the expansion curve
also changes, as there is more air to expand into the cylinder volume with large clearance than with small
clearance. These curves are indicated by the numbers 2', 3′ and 4', respectively.
Fig. 11.-Diagrams illustrating adjustable compression stroke method of regulation. Curve 1 indicates full
compression stroke. Compression starting at A rises to B, and discharges from B to E. Curve 2, intake valve held
open for 1/4 of stroke allows only 34 of cylinder volume to be compressed. Starting at A, air is forced out of
the cylinder from A to H, along atmospheric line. At point H, the intake valve closes and compression rises
H to C, and discharges C to E. Curve 3 represents similar action with intake valve held open for ½ stroke. Con-
sequently only ½ the volume is delivered to DE.


1268
Compressor Control Devices
How does an inlet line unloader work?
Ans. In operation, when the pressure is low in the receiver,
a spring overcomes the air load on a piston and forces the
valve open. With the inlet line open free air is drawn into the
cylinder. Again, when the pressure reaches a predetermined
point, it in acting upon the piston, pushes the valve shut which
shuts off the air supply and accordingly no more air is pumped
15
lov
19
SOLA
dia
OC
Fig. 12.-Three step regulator with air filter and the three-way cock (used for
unloading during the starting period). Note the indicator provided for each
step of unloading.
into the receiver until the pressure in the receiver drops below
the pre-determined working pressure.
How does actual construction vary from the arrange-
ment just described?
Ans. In the actual unloader there is a small piston which is
Compressor Control Devices
1269
LOW-PRESSURE
DIAGRAMS
FULL LOAD
HIGH-PRESSURE
DIAGRAMS




THREE-QUARTER LOAD


ONE-HALF LOAD



ONE-QUARTER LOAD

NO LOAD
Figs. 13 to 22.-Indicator diagrams showing operation of clearance control at
Five load points.
1270
Compressor Control Devices

~-
www.
17
16
4
VITR
འ་་་་
29
MANGO
5
14
15 13
7
12
8
D
29740
10
Fig. 23.-Sectional view of automatic clearance valve with locking screw and
enclosed cap for gas producer. It is of the automatic, piston operated type.
When special regulation is furnished, they may be of straight hand operated
type or of automatic type with set screw for keeping the valve closed when so
desired. The valve seat 2, fits into the inner cylinder wall with copper gasket 1
sealing the joint. The valve 17, is held on its seat by means of the piston and
the valve stem 4. The piston is moved by means of air pressure controlled by
the A-71 or A-72 clearance regulator. The air connection is at 11. Spring 16,
opens the valve quickly when air is exhausted from the piston, prevents flutter-
ing as the valve closes, and retains the valve seat 2, in the cylinder wall. The
piston consists of two pieces, a bull ring 12, and a piston head 8, which slide
into one another and hold a double ring of soft packing. A safety dowel pin
6, which is driven in the piston head, fits into a hole in the bull ring and permits
just enough relative movement of the two parts for two rings of packing-no
more and no less. This packing is of special material, which was chosen as a
result of careful experimenting. The soft packing rings require no "wearing in'
as in the case of metallic piston rings. Because of the construction of the piston,
the soft packing is squeezed firmly and evenly against the cylinder wall of the
valve cap as soon as air pressure is put behind the piston, thereby immediately
sealing it against air leakage. A light cup grease should be used to lubricate
the packing and to keep it in good condition. Stuffing box 15, seals the valve
stem against cylinder pressure in the clearance pocket. Gland 13, is pulled
up against soft packing 14, by gland nut 5. Pull up on gland nut 5, only
enough to prevent air leakage. The packing should be replaced when it must
be pulled up so tight that the action of the valve becomes sluggish. Do not
put fingers in the cap to adjust the gland when the regulation system is in
operation. Use proper wrench furnished with compressor. When necessary to
repack stuffing box, shut off air from regulating system. When the clearance
valve is hand operated, a separate screw stem, provided with a hand wheel.
screws through cover 10, and pushes against stem 4. In such cases the piston is
omitted. When the automatic valve is furnished with a set screw for locking the
valve closed, a separate screw stem, which screws against pistón head 8, is used.
Compressor Control Devices
1271
actuated by the pressure in the receiver against the resistance
of a spring. When the pressure in the receiver becomes too
high, the piston is moved sufficiently to open a small port which
admits air to a plunger valve of larger area.
This plunger valve is forced against its seat, thus preventing further

O
RA-79 RELIEF
VALVE
EXHAUST PIPE
TO ATMOSPHERE
RA-79 RELIEF
VALVE
CAL
CONNECT TO A-94 OR A-95
THREE-WAY VALVE.
Fig. 24.-Piping arrangement of cylinder relief valves on cylinder.
admission of free air to the cylinder until the pressure in the receiver
drops below the maximum pressure for which the mechanism is set.
Name a standard unloading method.
Ans. Usually free air unloaders are placed on each inlet valve.
What is the application of free air unloaders controlled
by auxiliary valve?
1272
Compressor Control Devices
Ans. This type of regulation is standard where the compressor
is driven at constant speed from any source of power, and where
the demand for air is fairly constant.
What happens when the receiver pressure rises to a value
for which the auxiliary valve has been set?
Ans. The auxiliary valve operates to admit live air to the
free air unloaders.

COMPRESSOR
OVER SPEED
TRIP
色​”
OIL PUMP
PRESSURE PIPE
TO OIL FEEDS
£50 303
FLY WEIGHT FOR
OVERSPEED KNOCKOUT
copsco
3836 F250
[séacs
SHUT DOWN
WEIGHT
CHAIN DRIVE
TRIGGER LATCH
HANDLE
OIL INLET
Fig. 25.-Safety stop valve and operating mechanism..
OIL
-PRESSURE
GAUGE
STEAM IN
SAFETY STOP VALVE
What is the effect of this?
Ans. The free air unloaders push all the inlet valves off their
seats, allowing air and gas to pass in and out through the inlet
valves while the compressor piston continues to move back
and forth.
How is the compressor unloaded for starting when there
is pressure in the receiver?
Compressor Control Devices
1273

OPERATION OF
SAFETY STOP VALVE
க
DI
cali mu
OL
ΟΙ
55922
Figs. 26 to 28.-Operation of safety stop valve 1. Starting position. Before the compressor can be started,
the shut down weight must be raised and latched by raising the trigger latch handle. The red spot indicates
a lack of oil pressure, as is the case while the machine is idle. 2, running position. As the oil pressure
rises, the trigger latch handle drops into running position. The red spot warning disappears. The trigger will
now function if oil pressure fail. 3, shut down. When the compressor stops, or if for any other reason oil
pressure fail, the trigger latch handle releases the shut down weight and closes the shut off valve. It must
be reset before the machine can be started.






1274
Compressor Control Devices
:
Ans. Screw on the wing nut at the bottom of the auxiliary
valve.
What is the effect of this adjustment?
Ans. Air will be admitted to the free air unloader and thereby
vent the compressor cylinder to the intake passage.
:
Compressor Operation
1275
CHAPTER 60
Compressor Operation
Assuming that the compressor plant has been properly in-
stalled, the operator taking charge should understand the
following instructions:
What is the preliminary procedure on taking charge of a
newly installed plant?
Ans. Clean up everything.
Especially the compressor. Wipe out thoroughly the compressor
interior. Clean the piston rod. Blow out all oil piping, passages and
pockets with a jet of air. Thoroughly inspect the compressor and give
whatever attention that may be necessary.
What should be noted about compressors shipped
assembled?
Ans. They require no adjustment of parts before starting.
How do you start a compressor?
Ans. Rotate or bar the compressor over a few times by hand
to see that it works freely and that everything is clean.
What next should be done with a new compressor?
1276
Compressor Operation

DRAIN
RECEIVER
TREN
TUV-
GAUGE
↓
SAFETY VALVE
AFTERCOOLER BY-PASS
AFTER-
COOLER
LONG
RADIUS
ELBOWS
POP SAFETY VALVE BETWEEN
SHUT OFF VALVE AND HP CYLINDER
INTERCOOLER
CONCRETE PAD IF GROUND IS SPONGY
Fig. 1.-Arrangement of intake piping and filter.
SPACE FOR REMOVING
INTERCOOLER TUBES
AIR FILTER SEVERAL
FEET FROM GROUND AND
HOODED TO PREVENT
ENTRANCE OF RAIN
**
INCREASE
2 IN DIAMETER
FOR EVERY IS IN LENGTH
INTAKE PIPE AS SHORT
AND DIRECT AS POSSIBLE
A.
53474
LONG RADIUS ELBOW
Compressor Operation
1277
Ans. Run the compressor without any pressure for an hour
or so.
What should now be done?
Ans. Turn on a full supply of cooling water to the cylinder
jacket.
How about the lubrication?
Ans. See that there is plenty of oil in the cylinder lubricator
and that the oil in the bed plate is at the proper level.
What precautions should be taken in starting?
Ans. Make sure that the tops of the wheels rotate toward
the cylinder.
How do you start a steam driven compressor?
Ans. Open the drain cocks on the steam cylinder and steam
chest, and drain the steam pipe above the throttle valve until
it is warmed up.
After draining open the throttle very little and let steam blow into
the steam cylinder until it is thoroughly heated, turning the compressor
over very slowly until all condensate is worked out. Then close cylinder
cocks and bring compressor gradually up to speed.
What should be done after the compressor attains full
speed?
Ans. Unscrew the wing nut and the compressor will begin
to operate normally.
What is used in place of the wing nut on gas com-
pressors?
Ans. A three way valve in the line between the auxiliary valve
1278
Compressor Operation

܂
Srza
10 x 10
11 x 12
13 x 14
15 x 16
11 x 10
13 x 12
15 x 14
18 x 16
20 x 16
15 x 10
17 x 12
20 x 14
14
A
10
3x 1013′ 3″ .| 53″
15 x 12
13 x 14
22 x 16
C
P.D
13'0° 53°
9.1"
14' 3" 51" 9.
!S′0″ | 56.8″ | 13.2″
17′0″ | 66.3″ | 13″
17' 0" 66.3° | 13°
BEAUTY
12′6″ | 53″ 91' 40½
13'951 9" 47%
15′ 3″ | 56 8″ ¦ 13,2″ 53516
16′ 9″ | 66.3″ | 13″ 646
9.1'
14′ 0″ | 51° 9'
15′ 0° | 56.8″ | 13.2″
17'0 66.3 13
13'0° 50.2" 9.1"
13′ 9″ | 48.5° 9.1'
16′ 0″ ·| 65″
13°
16′0″ | 65° 13°
Figs. 2 and 3.-Plan and elevation of electrically driven compressor with
dimensions indicated to correspond with the table below.
B
D
I
E
TABLE OF DIMENSIONS
SINGLE BELT DRIVEN COMPRESSOR
40½″ | 2′ 3″
49%* | 2′ 6″
56416" 2'9"
682 30
70156 3'5
A
in
O
F
WORT KING TON
¥
G
X-79844
G
• | H | I | J
| K |
22″ | 41% | 2′ 6½″ | 1′9″ | 11′ 3″ | 20″ 6° | 37°
2'3″ 47° 2′ 10″ | 2′0″ | 11′ 9″ | 2′ 0″ | 6″
26 5534"
2′ 6″ | 55¾¾″| 3′ 2½″ | 2′ 6″ | 12′ 4″ | 2′ 4″ | 6″
2'6' 5816" 3′ 9½″ | 3′0″ | 18′ 4′ 9′-6″
|
4016" 2'6"
44. 26 1'9" 11′ 3″ 20"
50% 2' 10"| 52½″| 3′ 3¹´ 2′0″ 13′ 9″ | 24″
5434′ 3′5″ 5676″
5"
3'
2′ 6″ | 15′ 0″ | .2′ 4″
56316 3'5 5851% 39½″ 2′6″ 14′ 10″ 2′ 2″
| 6'
|
L
P.D.
N
aaaa
FLOOK
FLOOR LAMP
98'
1438
2′ 6½″ | 1′9″ | 11′ 3″ | 20″
44″
6. 37″
·51½″ 2′ 1034″ | 2′0″ | 11′ 9″ | 24″ 6. 39'
585/16" 3′ 53″ 2'6" 14′ 4″ 2' 4"
2′ | | 2′ 6' 47" 14" 16"
3'
´·66%″ 3′ 9/2″ | 3′0″ | 18′ 1″ | 2′ 9″ | 6″ 52* | 19″
70 3' 9" 3'0° 18′ 10″ 2′ 6″ 6" 52" 2016"
|
|
|
6′
M
42½″ 2′ 3″ | 46″ .| 2′ 6¾½″ | 1′9″ | 11′ 3″ | 20″
51 28 59%″ 2′ 1134″ 2′0″ 13′ 9″ 24"
| |
5616 30 5816′ 3′ 44″ 2'6
|
14′ 4″ | 2′ 4″
70156 3'5 70
| 3' 92 3'0° 11′ 3″ | 2′ 9″ | 6″ | 52″ | · 20%
|
37′ | 1136″ .
39 16%
14
47
93%*
39″ | 123%
47 111316
52 1416
N

40'
936".
42° 1536
69″ | 134″
69° | 14¹″
N
Suct.
QOQUA QUAW
·H

O P Water
O
Dis. Inl Out.
3½" 3½"
5'
6.
8' 8"
10°
10°
6
6.
8° 8"
10° 10°
10° 10°
10″ 10°
and yard, g
1.
Gud har ba
I
11½"
1½
12
12
142
and and mad and und
KONA
14
1/
1½
\W\W
1½
1½½
I' 114°
1X
1/4″ 2″
Compressor Operation
1279
and the unloaders with one connection of the three way valve
piped to receiver.
Explain the method of control by variable clearance.
Ans. In this method a number of clearance pockets are
thrown into communication with the ends of each air cylinder

BOLT
////
SPECIAL PLUG
Fig. 4. Special steel plug and bolt for assembling or removing the wheels.
Compressors are always shipped with the wheels removed from the shaft, and
they should be put on in the following manner: To secure a gripping fit, the
bore of the wheel hub is a few thousandths of an inch smaller than the shaft
diameter. For this reason the plug which is furnished must be used in putting
on and taking off wheels. Remove the hub clamping bolt. Place special plug
in slot so that the boss on plug fits in belt hole as shown. Hold nut in slot and
turn bolt until end touches special plug and nut rests against opposite wall of
slot. Use wrench on outer end of bolt to tighten. As the bolt is turned, the
inner end will exert force against plug, thus spreading split hub so that wheel
can be placed on shaft or removed as shown. Wheels will be in proper position
when the end of shaft projects 1/8 in. beyond the face of the wheel hub on the
7 in. stroke and 316 in. on the 9 in. and larger sizes. The 7 in. stroke and smaller
compressors are usually equipped with heavy belt wheel only, the fly wheel
being omitted. For details see foundation plan furnished with the machine.
1280
Compressor Operation
Į
when the pressure in the receiver has reached the required
pressure.
What is its principle of operation?
Ans. When the compressor piston returns, the air in the
clearance pockets expands and partly fills the cylinder, thus
preventing the opening of the automatic inlet valves until later


10B
10
1076 4 55
LEHE
IOA
59
ΠΑ
CROSSHEAD
PIN HOLE METALLIC PACKING
COVER
53 53A
100000
THA
151 A

27 47
151 B
12 A
14
48
13
12
SOFT PACKING
3. 50 50A
151

55989
5
49
2
1400
1401
6 7 56 51 58 .57 52 26 A
DRIVING END
Figs. 5 to 8.—Bed plate connecting rod and cross head parts; oil dipper lubriį
cation.
Compressor Operation
1281
Part
No
1
IA
2
menoong
3
4
5
6
Bedplate, Connecting Rod and Crosshead Parts
7
10
10A
10B
11
11A
12
12A
13
Name of Part
Bedplate Complete with Metallic Packing (In-
clucics Parts 2 to 10B, 11A; 12A, 14, 151A, 151B,
1063 to 1067 and 1073 to 1076)
Bedplate Complete with Soft Packing (Includes
Parts 2 to 10B, 11 to 14, 151, 1063 to 1067 and
1073 to 1076)
•
Bedplate Bare (Includes Parts 8, 8B, 9, 27, 1073
and 1076)
Bedplate Oil Guard
Bedplate Cover
Pedplate Drain
Bedplate Guide Bar
*6A Bedplate Guide Bar Liner
Bedplate Guide Bar Tap Bolt
Crosshead Pin Hole Cover and Gasket
Crosshead Pin Hole Cover Yoke
Crosshead Pin Hole Cover Bolt
Partition Stuffing Box (Soft Packing Type)
Partition Stuffing Box (Metallic Ring Type)
Partition Stuffing Box Gland (Soft Packing Type)
Partition Stuffing Box Cover (Metallic Ring Type)
Partition Stuffing Box Gland Stud and Nuts (Soft
Packing Type)
Partition Stuffing Box Stud and Nut
Crosshead Oiler
14
27
Parts marked thus (*) not shown on cut.
Part
No.
46
47
48
49
50
50A
51
52
53
53A
54
55
56
57
58
59
151
151A
151 B
1076
1400
1401
Name of Part
Connecting Rod Complete (Includes Parts 47 to
53A)
Connecting Rod Bare
Crank Pin Box (2 pieces)
Crank Pin Box Wedge
Crank Pin Box Wedge Bolt, Nut, and Cotter Pin
(Includes Part 50A)
Crank Pin Box Wedge Bolt Lockwasher
Crosshead Pin Box (2 pieces)
Crosshead Pin Box Wedge
Crosshead Pin Box Wedge Set Screw and Nut
Crosshead Pin Box Wedge Set Screw Locking Sleeve
Crosshead Complete (Includes Parts 55 to 59)
Crosshead Bare
Crosshead Gib
Crosshead Gib Tap Bolt
Crosshead Gib Tap Bolt Lockwasher
Crosshead Pin, Washer, Tap Bolt and Lockwasher
Partition Stuffing Box Packing (Soft Packing Type)
Partition Stuffing Box Oil Wiper Ring (Includes
Part 151B)
Partition Stuffing Box Oil Wiper Spring
Bedplate Flange Stud and Nut
Crank Pin Box Shims
Connecting Rod Oil Scoop

1282
Compressor Operation
in the admission stroke. When no air is used from the receiver,
air from the clearance pockets may completely fill the cylinder
and prevent the opening of the inlet valves admitting no
free air.
What is the object of five step variable compression
regulation?
Ans. In this method there are five approximately equal
steps: full; 34; 12; 14; zero which regulates the degree of com-
pression.
•26A, 1069
9 8B

1069
24
1070
41301
8 1073 1074
21 A
Fig. 9.- Crank shaft main bearing and wheels.
1071
1072
1075
1063
1064
1065
1066
1067
1068
Compressor Operation
1283
Part
No
8
8B
.
20
21A
/ 26A
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
22*
22*
23*
23*
24
25*
25A*
Crankshaft, Main Bearings and Wheels
(7" Stroke and Larger Sizes)
Name of Part
Price
Main Bearing Cap (Right-hand) Right- and left-hand caps are identical for 7-inch stroke
Main Bearing Cap (Left-hand)
Main Bearing Stud and Nut
Crankshaft Complete (Includes Part 21A, 24, 1068; 1069, 1070, 1071 and 1072)
Crankshaft (Includes Part 26A)
Oil Dipper
Crankshaft Felt Washer
Crankshaft Felt Retainer
Crankshaft Felt Retainer Gasket
Main Bearing Side Cover
Main Bearing Side Cover Gasket
Roller Bearing Spacer Ring (Right-hand)
Timken Roller Bearing (Four required)
Roller Bearing Spacer Ring (Left-hand)
Shaft Collar and Oil Ring (Includes Part 1072)
Shaft Collar and Oil Ring Clamping Bolt and Nut
Main Bearing Stud Lock Washer
Main Bearing Side Cover Tap Bolt
Felt Retainer Tap Bolt
WHEELS
Flywheel (not furnished on 7" stroke Compressor) (Includes part 25A) for ES machine
Plain Flywheel (Includes part 25A) for FS machine
Belt Wheel (Includes part 25) for ES machine
Flywheel (Includes part 25A) for Adjustable-Speed Governor on FS machine
Belt or Flywheel Key
Belt Wheel Stud and Nuts
Flywheel Stud and Nuts
1173*
Texrope Sheave (Includes Part 25)
Parts marked with an (*) Asterisk are not shown on cut.
1284
Compressor Operation
What provision is made in the cylinder to obtain variable
clearance?
Ans. Each cylinder is equipped with four clearance pockets.
Describe the operation of the five step regulator with
push button starting station.
Ans. In operation, a slight rise in receiver pressure causes
the first step of control to operate and reduce the compressor
capacity. A further reduction in the demand for air results in
a slightly higher receiver pressure and causes the next step to
operate and so on to no load, if necessary, or until the com-
pressor output equals the demand for air or gas. The total in-
crease in receiver pressure from full load to no load is very
small. When desired the discharge pressure may be varied by
a screw adjustment on the top of the regulator.
What provision is made to accommodate the standard
two stage duplex compressor to the starting character-
istics of the synchronous motor?
Ans. Relief valves are provided on the high pressure cylinder,
and an unloader is provided on the inter-cooler.
How is remote control obtained?
Ans. To obtain remote control a magnetic unloader is em-
ployed which unloads the compressor during the time it is
being started or stopped.
Describe the by pass system.
Ans. In some special compressors, the cylinders are provided
with by pass passages, which connect the two ends of the
cylinder through the clearance pockets and allow air to by pass
back and forth without being compressed.
Compressor Operation
1285
In such, clearance valves are used to open or close these passages.
The valves may be hand operated, automatic or a combination of both.
What is this by pass valve used for on single stage com-
pressors?
Ans. To unload for starting.
What should be noted about the closing of by pass
valves?
Ans. They will not close automatically when there is no
pressure in the receiver. It is therefore necessary to close the
by pass valves by hand until enough pressure is built up in
the discharge line to hold them closed.
How do you regulate the cooling water?
Ans. Adjust the supply so that sufficient water is circulated
through cylinder jackets so that the discharge water feels warm
to the hand (approx. 100° to 110° Fahr.).
What precaution should be taken after running without
any pressure for an hour or so?
Ans. If the compressor show no signs of heating in the bear-
ings or stuffing boxes, the pressure may be increased gradually
up to the working point.
What is the next precaution that should be taken?
Ans. Watch the regulators (and governors on a steam driven
machine) and never leave the machine until satisfied that they
control the compressor properly.
What should be done after the compressor has run for
an hour or so and is thoroughly warmed up?
Ans. Go over the exterior of the machine and tighten any
1286
Compressor Operation
loose nuts. Gaskets squeeze up a little when new. Do not use
too much wrench pressure on the valve cover set screws as this
may spring the valve seats and cause leakage and excessive heat.
What next should be done?
Ans. Adjust the flow of cooling water to the proper tem-
perature so that the discharge feels warm to the hand.

L.P. STEAM
CYLINDER
O
SIGHT FLOW OILERS
TO RUNNING PARTS
INLET FROM
OIL RESERVOIR
FORCE FEED
LUBRICATORS
OIL
RETURN
DISCHARGE
TO
SIGHT FLOW OILERS
O
LAE
L.P. AIR
CYLINDER
01
I MAJO
O
OIL RESERVOIR

L
Figs. 10 and 11.—Elevation and plan of direct connected compound steam
driven four corner") two stage water cooled compressor showing general
arrangement and oiling system.
Compressor Operation
1287
What general attention should be given when the com-
pressor is running?
Ans. The compressor should be watched closely at the start,
particular attention.being given to the crank case. Even though
the compressor has been carefully cleaned, there is sure to be
more or less dirt remaining which will be washed out by the
circulation of the oil. All of this dirty oil must be removed.
What should be done with the oil when removed?
Ans. The oil removed may be filtered and used again.
How often should the oil be removed?
Ans. Once the compressor is in operation and the interior
thoroughly cleaned, it should not be necessary to change the
oil more often than once a month.
What attention should be given to safety valves?
Ans. Test the safety valves on the receiver and other places
occasionally.
How much oil is required for compressor cylinders?
Ans. Usually 1 to 5 drops of oil per minute according to size.
What precaution should be taken?
Ans. Too much oil will form carbon on the valves.
What attention should be given to belts?
Ans. For belt driven machines: 1, inspect belt regularly;
2, keep belt surfaces clean; 3, apply dressing to leather belt
which is too dry; 4, apply proper amount of dressing, enough
dressing in winter is too much in summer; 5, take grease out of
belting which is too oily; 6, do not expect too much from a
leather belt when subjected to temperature in excess of 100° Fahr.
1288
Compressor Operation
Which are the major wearing parts of a compressor?
Ans. 1, Piston rings; 2, cylinder or liner; 3, valve; 4, piston
rod.
How should the main bearing be adjusted with liners?
Ans. The bearing cap should be adjusted by means of these

LOL
WIPING EDGE OR LIP=
TOWARD CRANKSHAFT
CRANKCASE
SIDE
MHMES
IMPORTANT.
gaging
OXFORDDER
DIMETEORO
CYLINDER
SIDE
Fig. 12,-Partition plate oil wiper rings.
liners so that there is about .004 in. clearance between the cap
and the top of each side box.
What should be done before cross heads have been
worn in?
Compressor Operation
1289
Ans. Care should be taken to allow enough clearance to keep
the gibs from heating.
Describe the clearance setting.
Ans. Start with about .012 in. clearance and when the bear-
ing surfaces have been worn in, take up the clearance to
approximately .008 in.

CRANK CASE
SIDE
RINGS IN PARTITION PLATE
WITH WIPING EDGES
TOWARD CROSSHEAD
THIN RING MUST BEAT-
BOTTOM OF BOX
DRAIN
CYLINDER
SIDE
VENT
PARTITION PLATE INSTALLED
WITH DRAIN HOLES AT BOTTOM
AND VENT AT TOP
USE PAPER GASKET UNDER GLAND COVER
TO GIVE .005 TO .008 END CLEARANCE
FOR PACKING RINGS
Fig. 13.-Partition plate oil wiper rings for force feed lubrication.
What happens when wear occurs at the piston and
cylinder wall?
Ans. The piston naturally sets in a relatively lower position.
What should be done to compensate for this wear and
re-establish the original alignment?
1290
Compressor Operation
Ans. The cross head should be lowered an amount equal to
the wear.
What attention should be given to piston rod wiper
rings?
Ans. Clean the wiper rings periodically.
What should be done in the case of broken springs?
Ans. They should be replaced at once.
JOCH
CYLINDER
SIDE
ASSEMBLE THESE
THREE RINGS
TO WIPE IN THIS DIRECTION
ale
âgé d'o
WIPING EDGE OR LIP
TOWARD CRANKSHAFTS
IMPORTANT.
12A
GLAND
ISIA SPACER
13
15IB
ΠΑ
CRANK-
CASE
SIDE
DRAIN ON
BOTTOM
DRAIN
STUFFING BOX


CYLINDER
SIDE
DANDANDSEX
JJ00000.0,
LAPAL
Inannari
[DULTE
How are wiper rings assembled?
Ans. In assembling, stagger the joints.
ASSEMBLE THESE THREE RINGS
TO WIPE IN THIS DIRECTION
CRANK CASE
SIDE
DRAIN
ES
FS
Figs. 14 and 15.-Metallic ring type stuffing box located in the partition plate
where the piston rod passes through the crank case. On some gas compressors
this may be of the soft packing type, as shown in fig. 10.
What should be noted about piston rings?
Ans. They tend to rotate when in operation.
Compressor Operation
1291
In this connection what is the important procedure in
installation?
Ans. When installing, make sure that each three piece ring
has one right hand and one left hand outer ring so rings will
rotate in opposite directions and thus avoid the possibility of
the splits lining up and allowing leakage through the joint.
What is the most important requirement to get the
maximum efficiency out of any compressor cylinder?
www
ड
2 My (
4*1*51*1
A
We are THE
Tag warra
PACKING

STUFFING BOX
BUSHING
TWI
Fig. 16.-Stuffing box for air cylinder of single stage compressor. This general
construction is used for steam cylinders, some two and three' stage compressor
cylinders and sometimes for the crank case partition plate.



Figs. 17 to 19.—Installation of oil seal rings.
65361
1292
Compressor Operation
DISCHARGE VALVE
INLET VALVE
MACHINE SCREW
FLAT HEAD
QUE
CRAB
FILLISTER HEAD
MACHINE SCREW
1990:
J M14
M
STOP PLATE
→SEAT GASKET

MTUMOONOWE
TAMMENT
(1471 40 51500439NO
DIMENSION A
CHANNEL
Figs. 20 and 21.-Channel valve assemblies for inlet and discharge.
DIMENSION A
49517
SPRING
Ans. The admission and dis-
charge valves must be tight.
What inspection and atten-
tion should be given at reg-
ular intervals?
Ans. Inspect the valves,
valve passages and cylinder
bore and remove any accumu-
lation of foreign matter.
What precaution should be
taken with respect to clean-
ing a cylinder?
Ans. Never use kerosene,
gasoline or coal oil in air cyl-
inder to clean it out. This is a
very dangerous practice and
should be prohibited.
What should be noted about
free air unloaders?
Compressor Operation
1293
Ans. A complete understanding of the installation and opera-
tion of the free air unloader should be obtained by the operator
in order to maintain an efficient regulating system.

Fig. 22.-Lifting guide with flat chisel.

GAUGE
PRISESINATA POTÁSEKER
PR
AH
FACE OF SEAT
SHOULDER Å
ܢ
H
CHANNEL VALVE SEAT |||||
Fig. 23.-Gauge for maintaining distance from face of seat to shoulder.
Cold Weather Precautions.-Whenever the compressor is
exposed to a freezing temperature while not in operation, drain
the water from the jackets and inter-cooler in order to prevent
injury from freezing. Drain valves will be found at the side of
the cylinder for draining the jackets. The inter-cooler can be
drained through the valve provided for that purpose at the
water inlet connection.
If the compressor is to stand idle for any length of time, remove piston
rod packing. If this be not done, the packing will cause rods to rust very
rapidly, causing trouble later.
1294
Compressor Operation
Compressor

Operating Suggestions
WNY e
All Compressors.-1. Drain the receiver frequently and
regularly. An accumulation of oil in the receiver may cause an
explosion of oil vapor. A trap makes an ideal way of automati-
cally draining the receiver.
QUE 2 VON "LEA
•The 201
2. Test the safety valves on the receiver and other places
occasionally by means of the hand lever or by raising the air or
gas pressure to the proper blow-off point.
3. Keep a supply of cool water flowing continuously through
the water jacket of the air cylinder while the compressor is
running.
4. Keep the piston rod packing well set up, but not so tight
as to cause excessive friction or score the rods.
5. Keep compartment between piston rod stuffing boxes well
drained.
6. Usually 1 to 5 drops of oil per minute are sufficient for
lubricating the compressor cylinder. Too much oil will form
carbon on the valves.
7. Maintain a constant level of good clean oil in the crank
case.
8. Have regular times for inspecting the lubrication system,
inlet and discharge valves, also for cleaning the interior of the
compressor cylinder and water jackets.
Compressor Operation
1295
9. Inspect bearings occasionally, keeping them properly ad-
justed. Do not let a bearing pound.
10. Keep all bolts tight.
Gaskets will squeeze up a little with time. Do not use too much wrench
pressure on valve cover set screws, as this may spring the valve seats and
cause leakage and excessive heat.
Belt Driven Compressors.-For machines connected by belt
drive, note the following suggestions:
1. Inspect belt regularly.
2. Keep belt surfaces clean.
3. Apply dressing to leather belt which is too dry.
4. Apply proper amount of dressing. Enough dressing in
winter is too much in summer.
5. Take grease out of belting which is too oily.
6. Do not expect too much from a leather belt when sub-
jected to temperature in excess of 100° Fahr.
Steam Driven Compressors.-Note the following with this
type of drive. 1. Drain all low places in steam lines. Provide
automatic traps. Never connect a trap to more than one point
as a slight difference in pressure will prevent draining more than
one point.
2. Drain steam cylinder by opening drains as soon as the
machine is stopped.
To Shut Down Compressor.-First read chapter on Regu-
lating devices.
1296
Compressor Operation
After shutting down, shut off the cooling water, and on steam
driven machines open the steam cylinder and steam chest
drains.
If the compressor is to be idle for some time in freezing weather, be sure
there is no leak of cooling water or steam into the cylinders.
Extra precautions should be taken in freezing temperature
because a cylinder or head will surely crack if water be allowed
to freeze in it.
If the shut down be a long one, it is advisable to remove packing from the
stuffing boxes as it is apt to corrode and pit the piston rod when packing is
left in the boxes.
Gas Engine Principles
1297
CHAPTER 61
Gas Engine Principles
What do you understand about the term "gas engine"?
Ans. It's a term used incorrectly by most persons for an in-
ternal combustion engine which uses neither gas nor gasoline
for fuel but a mixture of air and minute globules of gasoline in
the proportion of about 14 to 17 parts air per part gasoline,
depending upon operating conditions.
Is there any such thing as a gas engine?
Ans. Yes. Any internal combustion engine is a gas engine-
when using gas, for instance City gas, or producer gas for fuel,
as in stationary practice or sometimes in marine practice.
What is generally understood by the term "gas" engine?
Ans. An internal combustion engine, either two or four stroke
cycle using gasoline for fuel.
How does it get the name of gas engine?
Ans. It was due to the ridiculous and misleading advertise-
ments of carburetors, calling them gasifiers, atomizers, etc.
No carburetor gasifies or atomizes gasoline-ridiculous-impossible..
What is the objection to the term "motor"?
Ans. An engine should never be called a motor.
1298
Gas Engine Principles

INLET
VALVE
(BEGINS TO
OPEN)
FUEL INLET
VALVE STEM GUIDE
VALVE STEM
VALVE SPRING
RETAINER
RETAINER PIN
LIFTER BOLT-
LIFTER GUIDE
LIFTER BARREL
CRANK CASE-
INLET CAM
SHAFT
INLET CAM-
OIL PAN
WATER JACKET
F
I
AAAAAAGÍ
WATER INLET
COMBUSTION CHAMBER
45°
WATER JACKET
WRIST PIN
CONNECTING
ROD
-CYLINDER
www
SPARK PLUG
WATER
OUTLET
15
Q
www x y z n
PISTON RINGS
PISTON
CRANK PIN
CRANK
vír
n
v
CRANK
SHAFT
CRANK SHAFT GEAR
45°
Ꮚ Ꮜ Ꮜ Ꮜ Ꮜ Ꮜ Ꮜ
vvtr
VALVE BONNET
AAAAAAL
EXHAUST
VALVE
(CLOSED)
EXHAUST
OUTLET
EXPANSION
CLEARANCE
(EXAGGERATED)
LOCK NUT
EXHAUST
CAM SHAFT
EXHAUST
CAM
EXHAUST CAM
SHAFT GEAR
INLET CAM SHAFT GEAR
wv
Fig. 1.-Cross section of a four cycle gas engine showing all the moving parts.
The type cylinder here shown is the T head so called on account of its projec-
tion on each side for the admission and exhaust valves. This arrangement
requires two cam shafts. The gears are proportioned for two revolutions of the
crank shaft to one of the cam shafts.*
*NOTE. -Save postage and don't write in, as one alleged critic did, to inform
us that the T head cylinder is out of date. It's necessary to show the old T type
cylinder so you can see both the admission and exhaust valves. Do you get the idea?
Gas Engine Principles
1299
In other words it is a general term rather than specific with the
notable exception of electric motor.
*
What are the essential parts of a gas engine?
Ans. 1, Stationary parts: a. cylinder; b, crank case; 2, Moving
parts: a. piston; b, connecting rod; c. crank shaft; d, fly wheel;
e, valve gear.
L HEAD

BUDIM
SEPARATE HEAD
INLET
:
INLET
VALVE
STEM
FLANGE
2
Đ
G
EXHAUST
EXHAUST
VALVE
STEM
Figs. 2 and 3.-Section and side view of L type cylinder showing admission
and exhaust valves on the same side.
The assembly of these parts is shown in fig. 1. The old T type of
cylinder is shown so you can see both the inlet and exhaust valves
and valve gear.
How does a gas engine derive its power?
Ans. From the heat generated by the combustion of a com-
bustible mixture within its cylinder, that is, a mixture of gasoline
*NOTE.-They all call a gas engine a "motor" and nothing can be done about
it, so why waste B.t.u.'s.
1300
Gas Engine Principles
in the form of a spray, mixed with air in proper proportions to
form a combustible mixture.
What is the cycle of a gas engine?
Ans. The series of events which are repeated in regular order
and which constitute the principle of operation.
How does the gas engine principle of operation differ
from that of the steam engine?

AIR FILTER
OIL FILLER TUBE
CRANK
CASE
SUPPORT
ARM
OIL
PAN
L
CYLINDER
1
**
VENT PIPE
CAM SHAFT
MAIN BEARING
CRANK
Fig. 4.—Side view of connecting rod showing parts and the oil passage ex-
tending from the crank pin bearing to the wrist pin bearing.
Ans. The gas engine represents the practical transference of
the furnace from the boiler to the working cylinder.
Define the term four cycle.
Ans. The term four cycle means four stroke cycle, the word
"stroke” being understood.
As applied to an engine, a four cycle engine is one so constructed
Gas Engine Principles
1301
that its cycle of operation is complete in four strokes, that is, in two
revolutions.
What name is given to the four strokes of the cycle?
Ans. 1, admission; 2, compression; 3, expansion; and 4,
exhaust.
FACE

RIB
GROOVES FOR
RINGS
WRIST PIN
SKIRT
Fig. 5.-Sectional view of piston showing location of ring grooves, wrist pin,
etc.
What name is usually given to the admission stroke?
Ans. They ignorantly call it the "suction" stroke-the word
suction should never be used.
1302
Gas Engine Principles
What names are sometimes given to the expansion
stroke?
Ans. The power or impulse stroke.
INTERCHANGEABLE
BUSHING
WRIST PIN BEARING OIL PASSAGE
MOULDED BEARING METAL
A
CRANK PIN
SHAFT
B
SHIMS
SECTION ON AB
Fig. 6.-Side view of connecting rod showing parts and the oil passage ex-
tending from the crank pin bearing to the wrist pin bearing.
DISENGAGING NOTCH
FOR HAND CRANKING
CAP

'CRANK PIN BEARING
GEAR TO OPERATE CAM SHAFT
HAND CRANK FOR
STARTING
BOLTS

COUNTERWEIGHTS
Fig. 7.-Crank shaft for one cylinder engine showing general appearance and
hand crank for starting.
Gas Engine Principles
1303
1 ADMISSION STROKE

INLET VALVE BEGINS TO OPEN
IJ
·45°
MII
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AAAL
wwwwwwww
vvvvvv
DODO
EXHAUST VALVE CLOSED
S
SAAAA.
..
AAAQ
In.
rrir
45
wwwwwwwwwiru
Fig. 8.-Admission stroke 1. Beginning of stroke.
Piston is at top dead center; the exhaust valve has just closed and the ad-
mission valve is beginning to open. Both cams are at an angle of 45° with
the axes. Rotation of the crank shaft is clockwise.
1304
Gas Engine Principles

2 COMPRESSION STROKE
·VALVE CLOSED
ந
ㅂ
​vvr vv v
AAAA
QAAAR
www
rrrrrr
crrvi
tal{
irr
20
OCDO
W
|||||
1
VALVE CLOSED
45°
ᎢᏌ ᏌᏌ ᏌᏊ
QARAM
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rv dr vv vv vv www
Fig. 9.-Compression stroke 1. Beginning of the stroke.
In this initial position the piston is at the bottom dead center position and both
valves are closed and remain closed the entire stroke. The object of com-
pression is to prepare the charge so that it will be in the condition which results
in most rapid combustion when ignited. Compression both heats the charge
and brings it under pressure (100 lbs. per sq. in. or more).
Gas Engine Principles
1305
Describe the 1st or admission stroke.
Ans. The first stroke of the cycle, (fig. 8), variously called
charging stroke (ignorantly, suction stroke), etc., is properly
called the admission stroke, because it is during this stroke that
the charge is admitted to the cylinder, the stroke begins with
the crank on top dead center for a vertical engine, and on head
end dead center for a horizontal engine.
Describe the 2nd or compression stroke.
Ans. During this stroke (fig. 9), the charge in the cylinder,
previously admitted during the admission stroke is compressed
by the movement of the piston toward the top end of the
cylinder.
Describe the 3rd or power stroke.
Ans. This stroke is known under varying names, such as
impulse, working, expansion or driving stroke. The stroke be-
gins with the crank at the top dead center, as in fig. 10.
What important event takes place at or just before the
beginning of the power stroke?
Ans. Ignition or lighting the charge by an electric spark.
What do you mean by the "charge"?
Ans. The amount of combustible mixture admitted to the
cylinder during the admission stroke.
What happens during the power stroke?
Ans. With ignition timed, explosion takes place approximately
at the beginning of the power stroke, attaining the maximum
pressure and as the piston advances expansion and cooling of
the products of combustion take place until pre-release.
1306
Gas Engine Principles

3 POWER STROKE
鹽
​VALVE CLOSED
·45°
!!!
vvvvvv
1. 185.
vis
[111] T
40
IGNITION
VALVE CLOSED
RAAM
rrrrrr
~~~~
r rv / v vvvvvvv
Fig. 10.—Power stroke 1. Beginning of stroke.
This is the only one of the four strokes of the cycle in which the engine develops
power and this highly intermittent action is the main reason for multi-cylinder
engines. Ignition is assumed to take place at top dead center position as here
shown. The firing of the charge increases its pressure several times so that the
piston begins its stroke with a heavy force acting upon its face.
450.
45°
rrrrtur
Gas Engine Principles
1307
What is pre-release?
Ans. The opening of the exhaust valve before the piston has
completed the power stroke.
What do you understand about the term pre-release?
Ans. It relates: 1, to the crank position at which the valve
begins to open; and 2, to the duration of the event in degrees
of crank travel.
What is the object of pre-release?
Ans. To let some of the products of combustion escape from
the cylinder before the completion of the power stroke, because
if not released before the end of the stroke, there would not be
time enough for them to escape without creating considerable
back pressure during the exhaust stroke.
What is drop?
Ans. The sudden fall of pressure due to pre-release. Pre-
release, although it reduces the pressure on the piston during
the power stroke and results in a small loss, avoids the greater
loss during the exhaust stroke due to excess back pressure.
In design, what determines the amount of pre-release
to be given to the exhaust valve?
Ans. The speed of rotation; the greater the r.p.m. the greater
the interval of pre-release to adequately reduce the pressure.
What is terminal pressure?
Ans. The pressure (due to the expansion of the gases) that
would exist in the cylinder at the end of the stroke if the ex-
haust valve were given no pre-release.
1308
Gas Engine Principles

4 EXHAUST STROKE
MHI
T
wwwww
SAA
irrrrrr
EXHAUST VALVE BEGINS TO OPEN
·45°
rrrrrtirr
6=*=
BUI!!!
T
RAAM
45°
rrívver
rrrrri
vvvvvv
Fig. 11.-Exhaust stroke 1. Beginning of stroke. In figs 8 to 11, the timing is
not set for the abnormal events for these see next page.
Gas Engine Principles
1309
Describe the 4th or exhaust stroke.
Ans. This is the last stroke of the four (stroke) cycle, in
which the burnt gases are exhausted.
What takes place during exhaust?
Ans. A large amount of heat is lost.
What are the normal events of the cycle?
Ans. 1, admission; 2, compression; 3, power or impulse;
4, exhaust.
The Abnormal Events
What are the abnormal events of the cycle?
Ans. 1, pre-admission; 2, post admission; 3, pre-release; 4,
release or exhaust; 5, post exhaust.
What is the object of pre-admission?
Ans. To facilitate the entrance or in flow of the charge.
What is the object of post admission?
Ans. With high (rotative) speed engines the momentum of
the rapidly entering mixture will cause a continuance of its
flow after the piston has reached the end of its stroke and
thus augment the charge.
What is the object of pre-release?
Ans. This has already been explained.
What is the object of post exhaust?
Ans. To clear the combustion chamber as much as possible
1310
Gas Engine Principles
of the burnt gases, by taking advantage of the momentum
(dynamic inertia) of the fast moving gases as they leave the
cylinder.
Name the inherent defects of the gas engine.
Ans. 1, only one impulse in two revolutions (per cylinder);
2, heavy fly wheel is required; 3, accessories such as fuel,


INLET VALVE OPENS
10° BEFORE
BEGINNING OF STROKE
H
dr
Addic
25
****
...
INLET VALVE CLOSES
CLOSES
45° AFTER
COMPLETION OF STROKE
POST ADMISSION
PRE-ADMISSION
10°
DODE
\WBIZZ
17
450
Figs. 12 and 13.—Timing of admission valve to open 10° before dead center
position and to close 45° after dead center position.
cooling, and ignition systems are required; 4, cranking is
necessary to start; 5, no overload torque available; 6, the en-
gine is not reversible; 7, a clutch is necessary; 8, has no reserve
or stored energy; 9, vibration; 10, noise; 11, operation depends
upon a carburetor; 12, operation depends upon ignition system;
13, any loss (by wear) of compression, reduces the power.
What is the reason for multi-cylinder gas engines?
Gas Engine Principles
1311


CONTINUOUS
EXPANSION
BURNT GASES
SHUT IN-
[AGDE
*MMER?/
1001111
HUN
QGDC
IMMESI
‚EXHAUST VALVE AT POINT OF OPENING.
911.
#thi
ト
​EXHAUST IN PHASE
WITH PISTON
NO PRE-RELEASE
Figs. 14 and 15.-Engine with valve gear arranged for continuous expansion
and for drop by pre-release. Here the exhaust valve is shown opening 45°
before the end of the stroke.
\\\\RAT/Z
45°
PRE-RELEASE
odac
T


100
EXHAUST VALVE
CLOSING 5° LATE
BURNT CASES
CARRIED OUT
BY INDUCTION
HIL
↓
L
POST-EXHAUST
Figs. 16 and 17.-Engine with exhaust closing at end of stroke and 5° late
showing effects in each case.
1312
Gas Engine Principles
Ans. Because of: 1, uneven turning effect; 2, excessive vibra-
tion; 3, large cylinder required; 4, tendency to stall.
Why are gas engines run at such high (rotative) speed
compared to that of steam engines?
Ans. To get some power out of them because there is only
one impulse or power stroke for each two revolutions per
cylinder.
The Valves
What kind of valves are used on gas engines?
Ans. Poppet valves.
Why is a poppet valve so called?
Ans. Because in operation it "pops" open and shut.
How many valves are required for each cylinder?
Ans. A minimum of two, in some cases four are provided.
What names are given to the valves?
Ans. Admission and exhaust valves.
Why?
Ans. Because they control the distribution of the charge into
and out of the cylinder respectively.
The admission valve is sometimes called the inlet valve, but this is
not the proper name for it.
Why are four valves sometimes used?
Ans. To obtain a greater area of port opening without re-
sorting to larger size valves and greater lifts.
Gas Engine Principles
1313
Why is a large area of port opening sometimes provided?
Ans. To obtain maximum horse power from a cylinder of
given dimensions, the excess area permitting the engine to run
at higher speed without reducing the amount of the charge
admitted.

SEAT
VALVE STEM
CLEARANCE
CAM SHAFT
W
ᏌᏌᏋ
VALVE
CAM
VALVE STEM GUIDE (BUSHING)
CYLINDER CASTING
·VALVE SPRING
SPRING RETAINER
RETAINER PIN
CLEARANCE ADJUSTMENT NUT
LOCK NUT
·FLAT FOR WRENCH
VALVE LIFTER (BARREL TYPE)
LIFTER GUIDE
HARDENED CONTACT SURFACE
www
CRANK SHAFT DRIVE GEAR
HALF DIAMETER OF CAM
SHAFT GEAR
CAM SHAFT GEAR
zzzzzzvvvv
Fig. 18.-Valve and valve gear assembled showing method of drive.
Why is the four valve arrangement called dual valves?
Ans. Because two of the valves (working in unison) are used
1314
Gas Engine Principles
for admission and the other two (also working in unison) are
used for exhaust.
Where are the valves located?
Ans. Usually on one side of the cylinder or in the head.

VALVE
STEM
'VALVE GUIDE
CLEARANCE COLD
солод
PLUNGER
A
E
F
D
11
C
B
Full
140
NOEL
BLO
ото
SEAT
GUIDE
SPRING
RETAINER CUP
RETAINER PIN
CLEARANCE AD-
JUSTMENT BOLT
LOCK NUT
FLAT
PLUNGER GUIDE
WEIGHT REDUCER/
HOLES
CAM
Fig. 19.-Valve gear assembly for under mounted cam shaft. Clearance is
exaggerated so it is easily seen. A, cam; B, plunger; C, clearance adjustment
bolt; D, retainer pin; E, spring; F, valve.
:
1315
Gas Engine Principles
What is the feature of valves located in the head?
Ans. The location provides most efficient distribution of the
charge and is the best arrangement for obtaining maximum
power.
What is the shape of the valve?
Ans. Usually cone shaped (beveled).
What provision is made in the head to facilitate grinding?

CLEARANCE
ADJUSTMENT ONCE
BALI.
JOINT
010
00
00
ROCKER
FULCRUM
PUSH
ROD
VALVE
SEAT-
-BARREL
FLAT
GUIDE
CAM
CLEARANCE
RETAINER CUP
AND PIN⚫
SPRING
ן
VALVE
GUIDE
Fig. 20.-Valve gear assembly for I head or valve in head design with under
mounted cam shaft.
9
1316
Gas Engine Principles
!
Ans. A slot or two holes are machined in the head to engage
with a screw driver or two prong bit respectively.
How are the valves usually constructed?
Ans. They are forged with the stem in one piece.
Of what materials are valves made?
Ans. Of high grade heat resisting steel.
What is the object of a hole or slot cut into the valve
stem end?
Ans. It is to provide for the retainer pin or key respectively
which retains the valve spring in position.
What is the usual angle of a beveled valve?
Ans. 45°.
The Valve Gear
What are the events of the cycle which must be con-
trolled by the valves under the action of the valve gear?
<
Ans. 1, pre-admission; 2, admission (proper); 3, post ad-
mission; 4, compression; 5, pre-release; 6, release (exhaust
proper); 6, post-release.
What two meanings have the events just listed?
Ans. They refer to: 1, the point or crank position at which
the events begin; and 2, the duration of each event.
How is the valve gear constructed?
Ans. The valves are moved by the valve gear at such times
Gas Engine Principles
1317
that the events of the cycle occur at pre-determined instants
assigned by the designer.
How are the events of the cycle specified?
Ans. They are referred to in terms of the angular position of
the crank measured to the top or bottom dead centers of
vertical engines.
On horizontal engines the terms head end or crank end dead centers
are specified which corresponds to top and bottom dead centers
respectively.
Does this indicate the time position of the piston?
Ans. No.
Why?
Ans. Because of the angularity of the connecting rod, pre-
viously explained.
The Normal and Abnormal Events
What is pre-admission?
Ans. 1, the point at which the admission valve begins to
open before the crank has reached top dead center; 2, the
duration of the opening of the admission valve before the crank
has reached the top dead center.
What is admission proper?
Ans. The period in which the admission valve is open from
the beginning to the end of the admission stroke.
What is post admission?
Ans. 1, the point of the compression stroke at which the ad-
mission valve seats in closing; 2, the period in which the ad-
mission valve remains open during the compression stroke.
1318
Gas Engine Principles
What is compression?
Ans. The period during which the charge is compressed both
valves being closed.
Review of Abnormal Events
What is pre-release?
Ans. 1, the point at which the exhaust valve begins to open
before the completion of the power stroke; 2, the period of
exhaust during the power stroke.
What is release proper?
Ans. The opening of the exhaust valve during the entire
exhaust stroke.
What is post-release?
Ans. 1, the point at which the exhaust valve seats in closing
after the end of the exhaust stroke; 2, the period in which the
exhaust valve remains open after the end of the exhaust stroke.
Which of the events are the abnormal events?
Ans. The pre- and post-events.
Why are abnormal events necessary?
Ans. On account of the difficulty of getting the charge into
and out of the cylinder without losses which tend to reduce the
power output.
Why are these difficulties encountered?
Ans. Because of the very high speeds (especially with auto-
mobile engines) now employed and other characteristics of
modern high speed engines.
Gas Engine Principles
1319
:
What is the reason for pre-admission?
Ans. To get some of the charge into the cylinder by induc-
tion, that is, by pressure reduction due to the momentum of
the escaping gases through the exhaust valve.
What other reason?
Ans. To obtain a partial opening of the valve at the begin-
ning of the admission stroke so as to avoid wire drawing during
the earlier part of this stroke.
What is wire drawing?
Ans. The effect produced by a gas flowing throughout a con-
stricted passage which results in a fall of pressure with its
attendant loss in engine operation.
What is the reason for post-admission?
Ans. To increase the charge by inductive admission.
That is, the charge momentarily continues to flow into the cylinder
by its momentum till slowed down and brought to rest by the rising
pressure in the cylinder, at which time the admission valve should close.
What is the reason for pre-release?
Ans. To avoid abnormally high back pressure during the
earlier part of the exhaust stroke.
What is the economic effect of pre-release?
Ans. It results in both a loss and a gain, but the gain is
more than the loss.
Reason this out for yourself.
What is the reason for post release?
Ans. To secure a scavenging effect by inductive exhaust.
1320
Gas Engine Principles
That is by the momentum of the fast flowing exhaust gases, which is
increased in the case of a long exhaust pipe, producing a partial vacuum
in the cylinder.
What do you understand by the term scavenging?
Ans. The getting rid of exhaust gases from a cylinder by
any means practical.
How long does it take a valve to open or close?
Ans. It depends upon the shape of the cam or driving mem-
ber of the valve gear.
What is the most desirable feature of valve motion
which cannot be obtained or even approached in practice?
Ans. The instantaneous opening or closing of the valves.
If valves could open and close instantaneously what re-
sults would be obtained?
Ans. 1, inductive pre- and post-admission would be more
efficient; 2, pre-release could be practically eliminated; 3, post-
exhaust would be more efficient.
*When does pre-admission begin?
Ans. A few degrees before top dead center, usually 5° de-
pending upon the type of engine.
*When does post-admission end?
Ans. About 40° after lower dead center.
At what point does pre-release begin?
*NOTE.-The values here relate in particular to modern automobile engines.
Gas Engine Principles
1321
Ans. About 45° before lower dead center.
On some engines 65° or more.
When does post-release end?
Ans. About 5° past top dead center.
Of what does a simple valve gear consist?
Ans. Referring to fig. 19. A, driving cam; B, plunger (and
guide); C, clearance adjustment bolt; D, retainer pin; E,
spring; F, valve and steam, the latter working in a guide.
What is the action of the cam A?
Ans. The cam is the driving member and receives its motion
from the main shaft through two gears although sometimes an
idler is interposed between the crank shaft and cam shaft gears.
How fast does the cam turn and why?
Ans. Half as fast as the main shaft because it takes two
revolutions to complete the four stroke cycle.
What does the cam drive?
Ans. The cam as it revolves transmits motion to the plunger
B (fig. 19) which works in a closely fitting guide to prevent
any lateral motion as the cam slides across the bottom of the
plunger.
How is wear reduced between cam and plunger?
Ans. To reduce wear to a minimum due to the cam rubbing
the same part of the plunger, the cam is located off center of
plunger, so as to turn the plunger to a new position each
revolution of the cam.
What other names are given to the plunger?
Ans. It is variously called tappet, lifter, etc.
Describe the clearance adjustment mechanism.
1322
Gas Engine Principles
Ans. This forms a part of the plunger and consists of a case
hardened bolt threaded into the top of the plunger and secured
by a lock nut.
Why is clearance necessary?
Ans. Due to expansion of metals with rise of temperature, it

·BETTINGU
Any
吾
​PLUNGER WRENCH A
LOCKNUT WRENCH B
ADJUSTING NUT WRENCH C
unn
Fig. 21.-Adjusting tappets or rotating lifters. Place wrench A, on flatted head
of lifter, wrench B, on the lock nut and wrench C on head of tappet screw.
While holding wrenches A and C, loosen lock nut with wrench B. Adjust
clearance with wrench C. After adjusting, hold wrenches A and C and lock
with wrench B.
is necessary to allow for this with a clearance space (when cold)
otherwise the valve would not seat when hot.
How is the spring retained in place?
Ans. Various locking devices or retainers are used for this
purpose.
Gas Engine Principles
1323
What is the object of the spring?
Ans. To close the valve when not acted upon by the cam.
How is the valve and its stem held in alignment with
the seat?
Ans. The stem passes through a guide which serves to hold
the valve in a central position with respect to its seat; thus
assuring that the valve will seat properly.
How does the cam shaft receive its motion?
Ans. Through suitable reduction gear transmission with the
main shaft of the engine.
How is the cam shaft driven?
Ans. By gears or chain.
In servicing the valve gear what are the main items to
be considered?
Ans. The springs and clearance adjustment of the valve lifter
or plunger.
What is the action of weak valve springs?
Ans. It results in a loss of economy and power of the engine.
What precaution should be taken?
Ans. Valve springs should be checked to be sure they have
not been weakened by the heat of the engine.
How about the practice of using screw drivers or other
makeshift tools to compress the spring so as to remove
its retainer?
1324
Gas Engine Principles
ADMISSION
PRE-ADMISSION
INLET
VALVE
OPENS
ROTATION
INLET VALVE
CLOSES
T.D.C.
POST-ADMISSION
ADMISSION
TOTAL
ADMISSION
DEAD
CENTER
AXIS
TOTAL
RELEASE
EXHAUST
RELEASE
T.D.C.
NORMAL EVENTS
ABNORMAL EVENTS
POST-RELEASE
G
EXHAUST VALVE CLOSES
EXHAUST VALVE OPENS
PRE-RELEASE
Figs. 22 and 23.-Valve timing diagrams for admission and exhaust, illustrating the normal and abnormal
events of the cycle.

Gas Engine Principles
1325
Ans. Such practice will not be resorted to by first class
mechanics as springs are sometimes distorted or bent by this
treatment.
How are broken and weak valve springs detected?
Ans. Broken springs are easily noticeable at idle, while weak
springs show up more during high speed performance by limiting
top speed since they allow the valves to "float," that is, not
follow the cams on the cam shaft.
How are tappets adjusted?
Ans. They may be adjusted loose or tight.
Loose tappets are noisy, but they can be set between loose and tight
to reduce noise without danger of non-seating at maximum heat.
Valve Timing
What do you understand by the term "timing the
valves"?
Ans. Timing the valves of a gas engine corresponds to
"setting the valves" of a steam engine.
How is the instant at which a valve begins to open or
when it closes expressed?
Ans. In terms of: 1, distance moved by the piston from top
or bottom dead center; and 2, degrees around the fly wheel
referred to dead centers.
What timing marks are placed on the fly wheel by the
manufacturer?
1326
Gas Engine Principles
Ans. They are as follows:
B.T.D.C...
A.T.D.C...
B.B.D.C..
A.B.D.C.
A (or I)C.
A (or I)O...
E.C..
E.O..
•
Before top dead center
(C
66
. After
Before bottom "
After
(C
<<
•*•
13
Exhaust
13°
Admission valve closed
(C
EXHAUST OPENING
UPPER
DEAD CENTER
INLET OPENS
INLET CLOSES
(C
68°
||||||||HTLASES/IKMANNIT
22
413°
261
"
<<
((
LOWER
BEAD CENTER
((
THI
TIMING POINT I.C.
TIMING
POINT 1.0.
13°
INLET
open
closed
open.
TIMING POINT_E.C.
CHAOKE OVERSEATT
(
OPENING
(6

$50.
Fig. 24.-Buick valve timing diagram, Series 40.
EXHAUST
CLOSES
13°
EXHAUST
OPENS
TIMING
POINT E.Q.
Upon what does the instant of opening or closing of a
valve depend?
Ans. Upon the angular position of the cam.
How is the timing altered?
Gas Engine Principles
1327
Ans. Evidently the timing may be changed by altering the
position of the cam shaft gear with respect to the main shaft
gear.
How is the correct meshing positions of the cam shaft
gear and the main shaft gear determined?
EXHAUST OPENING
UPPER
DEAD CENTER

INLET OPENS
INLET CLOSES
|33,
UBUR
ANEMIAN
'71°
25°
GRAND SILANI.
TIMING POINT I.C.
TIMING
POINT 1.0.
265°
INLET
LOWER
DEAD CENTER
1312°
MANU
TIMING POINT E.C.
OPENING
Spa
EXHAUST CLOSES
13°
EXHAUST OPENS
TIMING POINT E.O.
Fig. 25.-Buick valve timing diagram for Series 60, 80 and 90.
Ans. They have already been determined by the manufac-
turer and the two gears marked so that when they are meshed
with the marks opposite each other they are correctly set.
What gears are known as the timing gears? ·
1328
Gas Engine Principles
Ans. The half speed gear on the cam shaft and the crank
shaft gear.
How do you determine the correct position of the cam
shaft?
Ans. Turn fly wheel till piston is at beginning of the ad-
mission stroke. This is indicated by the movement of the tappet
in opening the admission valve. Note from manufacturers in-
structions the number of degrees before or after T.D.C. for
timing the admission valve. These degrees must be converted
into inches on the fly wheel rim to determine how far the fly
wheel must be turned to correspond.
Example. If the valve setting is to be for 8° pre-admission and
diameter of fly wheel be 12 ins. how many inches on rim must the wheel
be turned for this setting:
Inches to be turned
in which
***
π=3.1416
D= diameter of fly wheel in inches.
admission degrees.
Substituting
-
T
πDØ
360
→
3.1416 X 12 X8
360
Inches to be turned
=.84
Accordingly, on the fly wheel, lay off an inch on either side of T.D.C.
permanent marks and divide into tenths. Since 8° crank rotation cor-
responds to .84 in. on fly wheel, the T.D.C. mark must be turned this
distance from the pointer for the pre-admission. The distance .84 is
measured in a direction opposite to that of rotation.
Lubricating Systems
Great advances have been made in engine lubrication and
with proper attention trouble is rarely encountered.
Gas Engine Principles
1329
What system is generally used especially on automobile
engines?
Ans. The full pressure system.

OIL PUMP
PIVOT
STOP
MAIN
CIL PAN
-BRANCH PIPES
FA
CAM
SHAFT
SPIRAL GEARS
-BEARING
AIR TIGHT COMPARTMENT
-PLUG
DRILLED OIL DUCT
COUPLING
FLOAT OIL
SCREEN
DISTRIBUTOR
SCREEN
·LOW POSITION
■100€
NORMAL
OIL LEVEL
FILTERED
OIL OUTLET
·RELIEF VALVE
RELIEF
OIL FILTER
PRESSURE
GAUGE
SUMP
Fig. 26.-Elementary full pressure lubricating system. 1, detail showing pump
and connections to main bearings and crank pins. Pump housing top not
shown so that gears can be seen.
1330
Gas Engine Principles
What are its essential parts?
Ans. 1, oil pump; 2, inlet screen; 3, connecting pipes; 4,
drilled ducts; 5, oil filter; 6, relief valve; 7, pressure gauge;
8, oil level indicator.
Where does this system receive its oil?

SIDE VIEW
OIL
DUCTS
SHAFT
WRIST PIN
CONNECTING
ROD
END VIEW
SQUIRT-
HOLE
In
CRANK
PIN
CYLINDER
WALL
SUPPLY PIPE
Fig. 27.-Elementary full pressure lubrication system. 2, detail showing crank
pin, wrist pin and cylinder wall lubrication.
Gas Engine Principles
1331
Ans. Through a pipe leading from a depressed section or
sump in the oil pan which holds a proper quantity of oil.
How does it work?
Ans. In operation, the oil pump delivers oil directly to the
main bearings and oil continues under pressure through drilled
holes in the cranks to the adjacent connecting rod bearings and
from there, oil is forced out of the squirt hole in the upper half
of each connecting rod bearing, to the cylinder walls.
How are the wrist pins lubricated?
Ans. By oil holes through the upper portion of the wrist pin
boss.
How are the timing chain and sprockets lubricated?
Ans. Through a small passage from the main oil line.
The passage registers with a recess in back side of the cam shaft
thrust plate.
Describe the gear and chain lubrication.
Ans. A hole leading from recess to front side of plate is nor-
mally blocked by cam sprocket gear hub. Gear hub has a slot
which registers with hole in thrust plate once each revolution
and allows oil to be thrown to inside diameter of sprocket gear.
Holes in sprocket gear allow oil to pass to chain.
The general features of the full pressure system are shown in figs. 26
and 27.
Cooling Systems
Why is a cooling system necessary?
Ans. When the charge is ignited in a gas engine cylinder, the
1332
Gas Engine Principles
temperature of combustion ranges from approximately 2700° to
3200° Fahr. for low and high compression engines respectively.
This may be compared to the temperature within the furnace of a
steam boiler which rarely exceeds 3000°. Accordingly if means were
not provided for cooling the walls of the cylinder it would soon become
red hot, the piston would seize the cylinder walls and in a short time
the engine would be reduced to junk.
FILLER CAP

UPPER, TANK
RADIATOR TUBES
FAN
BELT
DRAIN
Ľ
·HOSE
LOWER TANK
OUTLET
HOT WATER
HALF TIME
GEARS
SHAFT
ASCENDING
RUBBER HOSE
INLET
WATER JACKET
WATER PUMP
COLD WATER FROM BOTTOM OF
RADIATOR BEING PUMPED IN
#HIHM
Fig. 28.-Front view of engine showing pump, fan and method of drive. In
Tate practice the fan and pump are combined into a single unit, the impeller
and fan being attached to the same shaft.
What event slightly cools the cylinder?
Ans. Admission.
What two events of the cycle cause the cylinder to heat?
Ans. Compression and combustion.
Gas Engine Principles
1333
Why?
Ans. Because of the relatively low temperature of the in-
coming charge and the evaporation of the spray or liquid
portion of the charge.
Why does evaporation of the spray result in a cooling
effect?

STEAM 2129
970.4 B.t.μ. LATENT HEAT
STEAM BUBBLES 2129
WATER 212°
180° SENSIBLE HEAT
180 B.t.u.
SP
Fig. 29.-Overhead automobile cooling system illustrating sensible and
latent heat.
Ans. The latent heat necessary to cause a change of state is
given to the liquid from the heated walls.
This results in cooling similar to re-evaporation in a steam cylinder
near the end of expansion.
What is the result of cooling a gas engine cylinder?
Ans. It results in a large loss of efficiency.
1334
Gas Engine Principles
Name two cooling systems in general use.
Ans. 1, the indirect air cooling system (ignorantly called
water cooling); and 2, the direct air cooling system.
What is wrong about the term "water cooled"?
Ans. It is wrong because the water doesn't do the cooling
but simply acts as a transmission medium to carry the heat to
WATER JACKET
FILIPINISKAPSUTAN KEMAHLETIKOM MAOVUNENQUEUR BALO BIN WOJ
HAKUNTANERLERIMINELTIS CARE MORBESALERSH
RIHIME HUMANOIDOMIEN OP TRUNK.
KAMANIPURETTUALISMANTLEDINGUSAMANAIN
HEAT TRANSFER MEDIUM
(WATER)
COOLING SURFACE
(RADIATOR)
MOTIVE FORCE
(PUMP)
COOLING MEDIUM
(AIR)

FAN
RADIATION FINS
POSITIVE CIRCULATION
Fig. 30.-Indirect air cooling system with positive circulation by pumps.
that part of the system where the air is applied (usually with
a fan) to cool the water and thus dissipate the heat.
This relates to a system in which the water is re-circulated.
Under what conditions may an engine be correctly
classed as water cooled?
Ans. In cases where the water does not re-circulate, such as
in marine engines.
What are the essential elements of an indirect air cooling
system?
Gas Engine Principles
1335
Ans. 1, water jackets on engine; 2, cooling surface (radiator);
3, connections between jackets and radiator; 4, motive force
to cause circulation; 5, air fan; 6, thermostat for automotive
temperature.
What two methods are used to cause circulation?
Ans. 1, positive (force pump); and 2, gravity (thermal
circulation).

M-41LATTIMA+AJAETEREOLENERALIEN
MATERNUDEILAPANGANT
MOTIVE FORCE
LIGHT HOT WATER
HEAVY COOL WATER
Lappe
auth
NATURAL CIRCULATION
(SO CALLED THERMO-SIPHON)
Fig. 31.-Indirect air cooling system with gravity circulation, usually called
thermo siphon circulation.
How is the pump run?
Ans. It is directly connected to the engine.
How does the gravity or "natural" circulation work?
Ans. Because of the difference in weight of water at different
temperatures, the cooled (heavy) layers of water over-balance
the column of hot water in the jacket and pushes it up, thus
causing circulation.
1336
Gas Engine Principles
What type of pump is generally used for forced circula-
tion?
Ans. The centrifugal pump.
How is the water cooled after absorbing heat from the
cylinders?
Ans. Usually by means of a radiator which is the part of the
NORMAL
CIRCULATION
2


RECIRCULATION
Figs. 32 and 33.-Diagrams illustrating operation of a thermostat by pass.
Fig. 32, normal circulating by pass open; fig. 33, re-circulating by pass closed.
In operation, when the water reaches a temperature of 140° to 150° the
thermostat valve starts to open and the circulation proceeds in the normal
way. At approximately 165° the thermostat is fully open, relieving the water
pump pressure on the by pass valve which automatically closes.
cooling system in which the heat absorbed by the circulating
water is transferred to the air.
How is a radiator constructed?
Ans. It is an assemblage of a multiplicity of very small
Gas Engine Principles
1337
passages of circular or rectangular forms constructed of very
thin metal to form the cooling surface.
The cooling surface is called the core, which is contained in an outside
casing.
What is the present method of temperature control?
Ans. It is to by-pass more or less of the circulating water so
that it re-circulates through the jackets without passing through
the radiator.
How is this accomplished?
Ans. By means of a thermostat.
What is a thermostat?
Ans. An automatic device for regulating temperature by the
unequal expansion of different metals, liquids or gases by heat.
What is used on some engines in place of a radiator?
Ans. The cylinders are provided with "fins" or equivalent,
cast integral which form considerable air cooling surface.
What is the "hopper" method of cooling?
Ans. For very small engines performing light or intermittent
duty, a very large jacket open at the top is provided which
holds a considerable amount of water which circulates thermally.
Mention a familiar application of this type outfit.
Ans. Hopper cooled engines are used on contractors' dia-
phragm pumps and other portable rigs.
1338
Gas Engine Principles
The Fuel Mixture
What is the fuel mixture?
Ans. Gasoline in a very finely divided state mixed with
sufficient air to burn it.
How is the mixture produced?
Ans. By the action of a carburetor.
What is a carburetor?
Ans. A device for breaking up gasoline into a very finely
divided state and mixing it with air in automatically varying
proportions to meet the variable running conditions of a gas
engine.
What is the best explosive mixture?
Ans. It has been found that the best explosive mixture with
the gasoline ordinarily used is a proportion of 14 or 15 parts of
air to 1 part gasoline by weight.
What are the proportions for engine operation?
Ans. It requires from about 13 to 16 times as much air as
gasoline to give a proper mixture for varying conditions of
engine operation.
What demand is made upon the carburetor?
Ans. The carburetor must automatically vary the proportion
of air to meet the ever changing conditions under which the
engine operates.
What is a rich mixture?
Ans. One containing a low proportion of air.
Gas Engine Principles
1339
What is a lean mixture?
Ans. One containing a high proportion of air.
What is a poor mixture?
Ans. One in which the proportion of air is not proper for
satisfactory engine operation.
It may be either too rich or too lean.
What is carburetion?
Ans. The process of mixing air and gasoline as performed
by a carburetor.
How is the fuel delivered to the carburetor?
Ans. Through a pipe line from the tank flowing by gravity
or forced by a fuel pump, according to whether the tank be
higher or lower than the carburetor respectively.
How is the mixture brought from the carburetor into
the engine cylinder?
Ans. It is forced in by a difference of pressure brought about
by the receding piston of the engine during the admission stroke.
What are the essential elements of the simplest type of
carburetor?
Ans. 1, receiving chamber (float chamber in the modern
carburetor); 2, adjustable spray nozzle; 3, mixing chamber;
4, throttle, as shown in fig. 34.
How does this elementary carburetor work?
Ans. In explaining basic principles of operation, it is assumed
that the receiving chamber be filled with gasoline and the
supply maintained at a level very near the elevation of the top
1340
Gas Engine Principles
of the spray nozzle. With engine running at constant load and
speed, the average vacuum produced in the manifold will re-
main constant and the excess atmospheric pressure outside the
mixing tube will force air up through the mixing tube. When
the needle valve is opened, atmospheric pressure will also force
gasoline through the fine bore of the nozzle and will enter the
mixing tube in a finely divided state, that is, in the form of a
spray.

MIXING CHAMBER
RECEIVING CHAMBER
*Tenten "gilacitet sileggja bla
Tomas CuZ SELVMODEL:
TO ENGINE-
-GASOLINE SPRAY.
GASOLINE LEVEL
SPRAY NOZZLE
OR SPRAYER
NEEDLE VALVE
AIR
Fig. 34.-Elementary carburetor illustrating principles.
How is proper proportions of air and gasoline obtained?
Ans. By adjusting the needle valve until the proportion is
correct for the conditions under which the engine is to operate.
Gas Engine Principles
1341.
What is the trouble with this arrangement?
Ans. The speed and load are always varying and each change
in these conditions must be met with a mixture of different
proportions.

MALTIJA,
SECONDARY
AIR INLET
JN
ADJUSTING NUT
SPRING
SECONDARY AIR VALVE
PRIMARY AIR INLET
Fig. 35.—Elementary carburetor with primary and secondary air supply.
What two methods have been used to vary the quality
of the mixture?
Ans. 1, the method of primary and secondary air supply;
2, primary air with variable fuel supply.
What is the effect of increase in manifold vacuum?
1342
Gas Engine Principles
Ans. The flow of gasoline from the nozzle increases faster than
the flow of air giving a mixture which grows richer.
How is the mixture prevented becoming too rich in
carburetors having a secondary air valve?
Ans. The secondary air valve automatically opens to admit
additional air as the vacuum increases which prevents the
mixture becoming too rich.

1
SOLID LIQUID
a
at-Drkum
KOTNOMICKM
HEAVY COLUMN
MANIFOLD
2
- - - - - - - -■
PARTIAL-
VACUUM
B
AIR AND LIQUID
LIGHT COLUMN
-AIR
BLEED AIR
AIR BLEED TUBE-
What is air bleed?
| THELICIAN PYOMA NAKILA
GASOLINE
AND AIR
GASOLINE
PRIMARY
AIR
Fig. 36.-The principle of air bleed as applied to carburetors.
How does the "plain tube carburetor" work?
Ans. In this carburetor there is no secondary air valve and
in its place what is known as air bleed is used.
Gas Engine Principles
1343
Ans. The admixture of a small amount of air with the
gasoline before the gasoline leaves the nozzle.
What are the two duties performed by air bleed?
Ans. It is used to avoid: 1, too lean a mixture on low vacuum;
and 2, too rich a mixture on high vacuum.

IDLING NOZZLE
HIGH VACUUM
THROTTLE
LOW VACUUM
MAIN NOZZLE
=
TERE!!LEN DEHT
S
C
IDLING AIR BLEED
B
UFT-
Fig. 37.—Elementary plain tube carburetor illustrating the idling system.
Name the various control devices that have been intro-
duced in plain tube carburetors.
Ans. 1, variable air bleed (economizer); 2, idling nozzle;
3, metering rod; 4, accelerating unit; 5, climatic control; 6, anti-
percolating unit; 7, slow closing throttle, etc.
1344
Gas Engine Principles
What is the economizer?
Ans. An air bleed fitted with a needle valve so that the
amount of air entering the nozzle can be varied to suit running
conditions.
What is the idling system?
Ans. Essentially a branch from the gasoline passage to the
main nozzle and extending upward at the side of the mixing

Air Enters Primary
Venturi Here
Q
Main Nozzle Delivers
Fuel Against Air
Stream
Insulating Blanket
Of Air Enters Here
And Again Here
|--
Fig. 38.-Triple down draught carburetor. In operation, the main nozzle dis-
charges the fuel at an upward angle into the primary venturi against the
downward air stream. The fuel, atomized in the primary venturi, is kept
centrally located in the air stream by the surrounding blanket of air passing
into the second venturi and again into the main venturi-offering a triple
protection against liquid fuel coming into contact with the walls of the
carburetor.
Gas Engine Principles
1345
chamber and terminating at the adjustable idling nozzle just
above the throttle.
What is a metering rod?
Ans. A long metallic pin of graduated diameters fitted to the
main nozzle or passage leading thereto in such a manner that
it measures or "meters" the amount of gasoline permitted to
flow by it at various speeds.

Ca
11
Metering Rod
Economy Steps
Power Step
Main Jet
Idle Jet
Idle Adjustment
Screw
Fig. 39.-Triple venturi down draught illustrating metering rod. The metering
rod provides both maximum power and economy without adjustment because
the metering rod which controls both the economy and power mixtures is
controlled by the position of the throttle and is positive in its action. With
throttle wide open, the power mixture is delivered; with partly closed throttle,
the economy mixture is delivered. This economy range covers all driving speeds
except wide open throttle. The power step covers all full throttle conditions,
whether pulling wide open on a hill or at maximum speed on the level.
1346
Gas Engine Principles
What is the accelerating unit?
Ans. It consists of a well, or a pump, the object being to
supply an accelerating discharge of gasoline or "shot" whenever
needed to give extra power as when the throttle is quickly
opened.
What is the anti-percolating unit?

HIGH VACUUM
MEDIUM VACUUM
VENT
ACCELERATING
TUBE
ACCELERATING
WELL
VENT-
MEDIUM VACUUM
LOW VACUUM
HIGH LEVEL
LOW LEVEL-
HIGH LEVEL
LOW LEVEL
| 4p 11 dan 20 © Shat had 9 4 -
L
ACCELERATING NOZZLE DISCHARGING GASOLINE
Figs. 40 and 41.-Elementary carburetor illustrating principle of the accel-
erating well system.
Ans. A device to prevent "boil over" consisting of a cap or
lid which when lifted allows excess pressure in the high speed
system to escape into the outside air.
What is the object of the slow closing throttle?
Ans. This unit has been developed to prevent stalling at the
critical moment when the engine working under heavy load
with abundance of fuel, is suddenly required to cease delivery
of power.
Gas Engine Principles
1347


OPEN
AIR BLEED
VALVE
FULL AIR
BLEED
PARTIAL
THROTTLE
IST
CONTROL
REDUCER
VALVE
FULL
THROTTLE
CLOSED
MINIMUM AIR
BLEED
PASSAGE
OGO,STANT
PR
(O
۱۳۷
Langitant HIN KAJ IN IN.
4*CRIC•>{{
CÂU NHL (PHLWØUR TULEJESSYwfild

Figs. 42 to 44.—Variable air bleed or economizer operation and economizer
reducer.
I
1348
Gas Engine Principles
What is the action of an automatic choker?
Ans. It enriches the mixture for cold starting and gradually
leans it out automatically as the engine warms up.
Super Chargers
Name an inherent fault of the gas engine.
Ans. Its failure to properly perform the first stroke of its
working cycle - that is, the admission stroke.
What is lacking?
Ans. The engine never takes in a full charge.
What is a full charge?
Ans. A cylinder full of mixture at atmospheric pressure.
Why doesn't it take in a full charge?
Ans. Numerous reasons such as: 1, inertia of the mixture;
2, pre-heating; 3, manifold friction; 4, wire drawing; 5, heating;
6, leakage.
When is the decrease in the amount of charge very
marked?
Ans. In engines running at high speeds and operating at
high elevations.
What is the result?
Ans. There is a considerable loss of power, that is, especially
at high speeds (and high elevations) the power is much less than
it would be if full fuel charges were admitted.
Gas Engine Principles
1349
How can this be avoided?
Ans. By means of a super-charger.
What is a super-charger?
Ans. A charge booster, or form of blower for increasing the
pressure of the mixture in the manifold in order to increase the
amount of mixture entering the cylinders during the period of
admission.
What is a super-charge?
Ans. A charge admitted above atmospheric pressure.
What are the effects of a super-charge?
Ans. High compression, considerably higher initial pressure
of combustion and during expansion resulting in a higher mean
effective pressure with corresponding increase in power.
Why do gas engines lose power at high elevation?
Ans. On account of the decrease in atmospheric pressure,
less mixture is admitted to the cylinders resulting in the
decrease of power.
What are the essentials of a super-charger?
Ans. These are shown in fig. 45.
How does it work?
Ans. Referring to fig. 45 the mixture is drawn in at A, by
the rotor of the blower and builds up a pressure above that of
the atmosphere at B. Accordingly when the inlet valve opens
on the admission stroke, the mixture is forced past the valve so
that even during the pre-admission period before the piston
has quite reached the top dead center, the mixture is flowing
1350
Gas Engine Principles
into the combustion chamber and cylinder, the motive force to
move the mixture being much greater than that due to induc-
tive exhaust during the post exhaust period of exhaust valves
timed for late closing. The result is that as the position traverses
its admission stroke, the incoming mixture is able to follow it at
a pressure greater than atmospheric at highest engine speeds.
How much admission pressure is obtained with a super-
charger?

CENTRIFUGAL BLOWER
OR
SUPER-CHARGER
INLET MANIFOLD
100000-B
ע
A
DODC
SIDE (SHAFI
WORM AND WHEEL
MILI
FRIN
=
GEARED TO 5 OR 6 TIMES
CRANK SHAFT SPEED
Fig. 45.-Elementary centrifugal type super-charger showing essentials.
Ans. A few pounds above atmospheric pressure, more or less
depending upon the speed of the blower.
What two types of blower are used?
Ans. 1, the centrifugal; and 2, the positive displacement.
Gas Engine Principles
1351
What other advantage except increase in power is claimed
for super-chargers?
Ans. A more thorough mixing of the mixture.
This claim is probably overrated.
Ignition Systems
Tthe reader should have a fair knowledge of electrical prin-
ciples before trying to understand ignition systems.
What are the two methods generally used in igniting the
charge in the cylinder of a gas engine?
Ans. 1, by an electric arc (low tension ignition); 2, by an
electric spark (high tension ignition).
What other names are popularly given to low tension
and high tension ignition?
Ans. Make and break and jump spark respectively.
What is the basic differences between low tension and
high tension ignition?
Ans. The low tension system is electrically simple and
mechanically complex, while the high tension system is elec-
trically complicated and mechanically simple.
Define the word tension.
Ans. It means the same as pressure or voltage.
What is the basic difference between low and high tension
ignition?
1352
Gas Engine Principles
Ans. Low tension ignition depends upon self-induction to
produce an arc, whereas high tension ignition depends upon
mutual-induction to produce a spark.
What is the difference between an arc and a spark?
Ans. To produce an arc, an electric current must be flowing
in a circuit before the circuit is broken. A spark is produced
when the voltage becomes high enough to start a current and
cause it to jump an interruption in the circuit.
What is the interruption in the circuit called?
Ans. A gap.
What is the basic wiring difference between low and high
tension ignition systems?
Ans. Low tension ignition is a one circuit system while high
tension ignition is a two circuit system.
What do they call the two circuits of a high tension
system?
Ans. 1, the primary or low tension circuit; and 2, the
secondary or high tension circuit.
What are the three essential elements of a low tension
or make and break system?
Ans. 1, low voltage current source (usually a battery);
2, ignition or circuit breaker; 3, primary or self-induction coil.
Of what does an igniter consist?
Ans. It consists of two electrodes or circuit breaking term-
inals, one of which is stationary and the one movable.
The stationary terminal is insulated, while the other having an arm
within the cylinder and placed conveniently near is capable of being
Gas Engine Principles
1353
moved from the outside so that the arm comes into contact with the
stationary terminal and separates with great rapidity (due to the
action of a spring when released).
What gear is necessary to operate the movable terminal?
Ans. A cam, trip arm, spring and advance arm.
What is the vital principle upon which the production
of the arc depends?
Ans. The breaking of the circuit by the igniter movable arm
must be done with extreme rapidity, to get maximum self
induction*.
How does the low tension or make and break ignition
system work?
Ans. In operation (fig. 46) two sources of current are shown;
either may be used by turning the switch to S or T. As the
nose of the cam G, passes the rod F, the latter suddenly drops
by the.action of the spring H. The head of the rod which has
been raised by the cam somewhat above the arm D, will in its
descent strike D a blow which abruptly breaks the contact
between D and B (maybe if the spring be strong enough), thus
producing an arc (maybe to repeat if the spring be strong
enough). When not acted upon by the head of the rod F, D, is
held in contact with B, by the spring E.
How is the timing of the arc adjusted?
*NOTE.-At an early date, the author, stuck off shore in a small motor boat,
after considerable cranking and with much profanity, recalled this principle, and
accordingly after strengthening the ignitor spring by stretching it, was able to
start without difficulty. The answer to this story is, if a stubborn gas engine,
especially a marine gas engine, doesn't start on the second cranking, sit down and
think. Of course if the battery be “down” (and you should have a battery tester)
you are licked get a tow.
>
1354
Gas Engine Principles
Ans. By the advance lever which pushes the trip rod away
from or toward the arm of the movable electrode D.
For what is low tension ignition especially adapted?
Ans. Formerly for marine service but now for stationary
service, owing to the advances made in high tension ignition.
What are the five essential elements of a high tension
ignition system?

Σ
MAGNETO
S
K
PLAIN
COIL
C
#°
B
T
SWITCH
D
KANIU
IGNITER
E
SWITCH
F
ADVANCE
H
IGNITER
ооооо
D%
BATTERY
Fig. 46.-Low tension or make and break ignition.
Ans. 1, low voltage current source (usually a battery);
2, condenser; 3, primary element of distributor (breaker);
4, secondary or mutual induction coil; 5, secondary element
of distributor; 6, spark plug.
How are the devices connected?
Ans. In two independent circuits known as: 1, the primary
or low tension circuit; and 2, the secondary or high tension
circuit.
Gas Engine Principles
1355
What devices are included in the primary circuit?
Ans. 1, low voltage current source (usually a battery); 2,
primary winding of the coil: 3, primary element of the dis-
tributor; 4, condenser.
What devices are included in the secondary circuit?
Ans. 1, spark plug; 1, secondary winding of the coil; 2,
secondary element of the distributor; 3, spark plug.
What is a secondary or mutual induction coil?
MANY TURNS
OF FINE
WIRE
SECONDARY
WINDING
∞
wwwwwwwwww
HIGH
VOLTAGE
FEW TURNS
OF HEAVY PRIMARY
WIRE
WINDING

T
LOW
VOLTAGE
CORE
Fig. 47.-Secondary coil with windings shown separate for clearness in the
diagrams.
Ans. A device used to obtain the high voltage necessary to
produce a spark.
Of what does a secondary coil consist?
Ans. It is virtually a primary or self-induction coil (as used
in low tension ignition) having wound over the low tension
primary winding, a secondary winding of relatively fine wire
and relatively very many turns.
1356
Gas Engine Principles
How does a secondary coil work?
Ans. When an electric current is passed through the primary
winding, it magnetizes the core, thus producing a magnetic
field in the surrounding space. Any increase or decrease of
current in the primary winding induces a current in the secondary

SECONDARY
PRIMARY
SECONDARY COIL
Fum
שר
METAL OF ENGINE (GROUND)
STORAGE BATTERY
\\\\\18////
4
SWITCH
011
MUNO
18
MEISIE |
|||}}}}|
-INSULATED TERMINAL
SPARK PLUG
་ .
18090-4
931 ··
CONDENSER
CIRCUIT BREAKER
W.I,/
H
Fig. 48.—Elementary diagram showing working of the ignition system.
winding; this induced current lasts only during the time of
increase or decrease of the current in the primary winding.
Upon what does the voltage of the induced current in
the secondary winding depend?
Gas Engine Principles
1357
•
Ans. Upon the ratio of turns of the two windings; upon the
sizes of the wires and upon the rate of variation of the current
strength in the primary circuit.
Is a spark produced upon making or upon breaking the
primary circuit?
Ans. Upon breaking the circuit.
Why?
Ans. Magnetic change takes place more quickly upon break-
ing the circuit, this being more efficient to induce sufficient
voltage in the secondary circuit to produce a spark.
What condition is necessary to insure a spark?
Ans. The current in the primary winding must be brought
to rest with great rapidity.
How is this accomplished?
Ans. By means of a condenser.
What is a condenser?
Ans. A device to absorb or store up a charge of electricity.
Of what does it consist?
Ans. It consists of numerous sheets of tin foil connected
together in pairs and separated from each other by insulating
material known as a dielectric.
How does a condenser work?
Ans. It may be compared to a reservoir that absorbs or
momentarily stores up current that has had its free flow
suddenly checked and in so doing builds up voltage between
the plates of the condenser.
1358
Gas Engine Principles
When does the checking of the current occur?
Ans. Each time the primary circuit is opened.
How is a condenser connected in the primary circuit?
Ans. In parallel or across the terminals of the circuit breaker
which closes and opens the primary circuit.
How does a high tension or jump spark ignition system
work?
0000
A
SPRING
CONDENSER
0000
CURRENT DUE
TO"MOMENTUM"
CHARGING
CONDENSER
TO "KICK"
CONDENSOR | CHARGED READY
ACCUMULATOR]
ACCUMULATOR
OPPOSING PRESSURE
OF CONDENSER
ACCUMULATOR
VALVE
oooo
CONDENSER
ACCUMULATOR
CURRENT)
WATER
C
DISCHARGED
CHAR
MG
BROUGHT TO
REST
HYDRAULIC ANALOGY
CONDENSER ACTION
IGNITION CIRCUIT
Fig. 49.-Detail of primary circuit showing current condition at make and break
and operation of condenser. A, circuit closed, water valve open. Current
flows around battery circuit; water from upper to lower tank. B, breaker open,
valve closed. Current charges condenser; water flows into accumulator. C,
opposing voltage of condenser kicks back current bringing it to rest; accu
mulator kicks back water, bringing it to rest.
•


OF
IN
•
Gas Engine Principles
1359

JUNCTION
SECONDARY COIL
HHI
GUMU:
ช
-TO GROUND
Fig. 50.-Secondary three terminal coil showing connection of primary and
secondary windings.
BATTERY
TO BATTERY
SWITCH
TO SPARK PLUG

CONDENSER
4444
2
3
1
AWEZAW
GROUND
2
3
HIGH VOLTAGE
4
2
Fig. 51. Single spark synchronous ignition system.
13
LOW VOLTAGE
4
DISTRIBUTOR
1360
Gas Engine Principles
Ans. In operation, (fig. 48) when the circuit switch is closed
current flows from the + (positive) terminal of the battery to
the primary coil via switch and contact maker. The current in
passing through the primary winding magnetizes the core.
The current passes from the primary winding to the negative
terminal of the battery, thus completing the primary circuit.
IST. VIOLINS
(ALTERNATOR)
2ND VIOLINS
SYN. MOTOR)
ACCOMPANYING INSTRUMENTS
IN UNISON
IN STEP
101560
F.D.G. OR 18

TOOND
Fig. 52.-Musical definition of the term synchronous. In an orchestra,
sometimes the 1st and 2nd violins play in unison, that is, the same notes
at the same time. Similarly, a synchronous motor (like the 2nd violins)
operates (plays) in unison with the alternator (1st violins), that is, similar
inductors cut similar lines of force at the same time; in other words,
a synchronous motor keeps in phase with the alternator which drives it. The
speed of the motor is therefore fixed by the frequency of the supply. It should
be noted that this is the ideal case of no load. If a load be put upon the motor
it will cause a phase difference between the two machines, sufficient to balance
the load.
At the instant the breaker contacts of the timer close and
during the short interval in which the primary current is
"getting started" and building up to full strength, voltage is
induced in the secondary winding, but not enough to break
down the resistance of the air gap of the spark plug. This is
because the induced voltage depends not only upon the wind-
ing ratio but upon the ranidity of magnetic changes in the
Gas Engine Principles
1361

CENTRIFUGAL BLOWER
OR
SUPER-CHARGER
INLET MANIFOLD
BY-PASS
PIPE
G
RELIEF VALVE
POSITIVE
DISPLACEMENT
BLOWER
Որոտ
0000
The 131 at
WORM AND WHEEL
[GEARED TO 50R 6 TIMES
CRANK SHAFT SPEED
Fig. 53. Elementary centrifugal type super-charger showing essentials.
AGOL
b
SIDE SHAFT
Denje
Puitse
**1.
1998-
1001
☆

\\{8}??-
Fig.54.-Elementary positive displacement type super-charger showing relief
by-pass, etc.
1362
Gas Engine Principles
core and in this case the building up of the magnetic field is
not quick enough. Accordingly, the spark does not occur at
make. However, when the timer contacts open, the current
tends to keep flowing and having its path suddenly inter-
rupted by the opening of the timer contacts, and by virtue
of its "electric momentum" surges into the condenser. In so
doing it encounters a rising opposing or reverse voltage due to
the action of the condenser. Finally this reverse voltage be-
comes so high (much higher than the battery voltage) that it
overcomes the momentum of the current. At this instant the
condenser "discharges" that is, kicks back the primary current
with such force that the magnetism of the coil collapses with
great rapidity with the result that the demagnetization of the
coil is much more rapid than its magnetism. Accordingly, the
voltage induced in the secondary winding during de-magnetiza-
tion is much greater than during magnetization in fact suffi-
ciently great to cause the induced voltage to overcome the
resistance of the spark plug and gap and produce a spark.
Diesel Engines
1363
CHAPTER 62
Diesel Engines
What is a Diesel engine?
Ans. A high compression internal combustion engine which
depends upon the heat of compression for ignition.
Just what is a so-called semi-Diesel engine?
Ans. A misnomer.
Why?
*Ans. There is no such thing as a semi-Diesel engine and it
would require a stretch of the imagination to understand why
a medium or low compression engine which cannot ignite by
the heat of compression is called by some "semi-Diesel". The
term should never be used.
Just what is a so called "full" Diesel engine?
Ans. Another misnomer.
*NOTE.-According to Raabe, the noted authority on internal combuston
engines, "There is nothing more 'semi' about these engines than there is about
any other type, be it two stroke or four stroke. In fact, these engines antedate the
Diesel. Ignorance has coined the term (semi-Diesel) and convention has propagated
it." Since these alleged semi-Diesels were in existence before the Diesel engine
was invented, the author would like to know what did they call them then? As
Puck use to say in the golden nineties: “What fools these mortals” be!
1364
Diesel Engines
Why was it introduced?
Ans. Manufacturers of genuine Diesel engines, no doubt
were compelled to introduce the term full Diesel to distinguish
their engines from the so called semi-Diesel type, that is, from
surface or spark plug ignition engines.

GAUGE PRESSURE
500
400
500
200
100
+
+
·INJECTION ENDS
INJECTION BEGINS
CLEARANCE
CLEA
EXHAUST
ATMOSPHERIC LINE
COMPRESSION
BEGINS
SUCTION
Fig. 1.-Typical indicator card of Diesel four cycle engine. It will be noted
from the diagram that the pressure range is much greater than in other engines
which accounts for the massive construction.
Name two general classes of Diesel engine.
Ans. Four cycle and two cycle.
Diesel Engines
1365
-
¡
"
K

A
Progressive Tracing
Diesel Card
ADMISSION
POWER
(EXPANSION)
of

B
COMPRESSION

EXHAUST
C
DY
Figs. 2 to 5.—The Diesel cycle represented progressively by indicator card.
A, admission stroke — charge comes in below atmospheric pressure line;
B, compression stroke-heat generated for ignition; C, power stroke
products of combustion expand; D, exhaust stroke-burnt gases ejected
above atmospheric pressure.
1366
Diesel Engines
Four Cycle Diesel Engines
What are the four strokes of a four cycle Diesel engine?
Ans. 1, admission; 2, compression; 3, power; 4, exhaust.
GAS ENGINE
DIESEL


AIR AND FUEL
ADMITTED
त
(JACK)
[300]
A A
AIR
ONLY
ADMITTED
ADMISSION
STROKE
Figs. 6 and 7.-Comparison of gas engine and Diesel cycles. 1. Admission
stroke.
What occurs during the admission stroke?
Ans. Air is admitted into the cylinder. Fig. 7.
What occurs during the compression stroke?
Ans. The air previously admitted is compressed to about
500 lbs. pressure which causes its temperature to rise to about
Diesel Engines
1367
1000° Fahr. As this pressure is reached gradually it does not
cause a shock to the engine, such as an explosion to the same
pressure would give. See Fig. 9.
Describe the events of the power stroke.
Ans. At the beginning of this stroke, as in Fig. 11, the fuel
is injected into the cylinder and meeting the highly heated air,
GAS ENGINE
DIESEL


LOW
COMPRESSION
AIR AND FUEL
COMPRESSED
h350
081
HIGH
COMPRESSION
AIR
ONLY
COMPRESSED
COMPRESSION
STROKE
IEEE
BO
FOTO A
911
*
Figs. 8 and 9.—Comparison of gas engine and Diesel cycles. 2. Compression
stroke.
it immediately ignites by the heat of compression and burns
throughout the period of injection, this period being a small
percentage of the stroke. The resulting pressure of combustion
forces the piston down on its power stroke.
1368
Diesel Engines
What occurs during the exhaust stroke?
Ans. The products of combustion are expelled through the
open exhaust valve, as in fig. 13, thus completing the cycle.
What is the general construction of a Diesel engine?
CHARGE IGNITED BY
ELECTRIC
SPARK
GAS ENGINE
FUEL INJECTION
CHARGE
IGNITED BY
HEAT
OF
COM-
PRESSION
POWER
STROKE
DIESEL


SCO
………
*
Figs. 10 and 11.—Comparison of gas engine and Diesel cycles. 3. Power or
expansion stroke.
Ans. The Diesel engine has many parts in common with the
gas engine, but are made heavier to adapt them to the more
severe cycle.
Diesel Engines
1369
:
!
Compression Pressures wh
What is the vital feature of Diesel engines?
Ans. High compression, much higher than in gas engines.
Why is such high compression necessary?
Ans. Without high compression there would not be enough
GAS ENGINE
DIESEL

Muscl TH
2
Batist
HANN
Ju
PRODUCTS OF
COMBUSTION
EXHAUSTED
EXHAUST
STROKE
JU!
FOO
H
Figs. 12 and 13.-Comparison of gas engine and Diesel cycles. 4. Exhaust
stroke.
heat of compression to ignite the charge and accordingly the
engine could not operate.
What determines the air temperature at the time of
fuel injection?
1370
Diesel Engines
I
I
:
·
W
Ans. The degree of compression.
What are the compression ratios usually employed in
the United States?
Ans. They range from 11 to as high as 19 to 1.
FUEL CHECK
FUEL OIL
FUEL
PUMP
AIR STARTING VALVE
·SPRAY VALVE
90 LBS.

FIRST
STAGE
COOLER
WORKING.
CYLINDER
SECOND STAGE 800 LBS
COOLER
Ø
700 LBS
SPRAY
BOTTLE
STARTING
BANKS
Fig. 14.-Elementary air injection Diesel showing two stage compressor and
other auxiliary apparatus.
Fuel Injection Methods
How many methods of fuel injection are employed and
what are they?
Ans. Two: 1, air injection; 2, airless injection.
Diesel Engines
1371
1
Non-descript names for the second method, such as solid, direct,
mechanical and what not should not be used.
What is air injection?
Ans. In this method, as shown in fig. 14, air compressed to
several hundred pounds higher than the compression pressure
is used to force the fuel charge into the cylinder.
Describe the method more in detail.
Ans. The highly compressed injection air is, at the proper
moment, blown into or over a measured charge of fuel, thus
forcing the fuel into the cylinder and thereby aiding com-
bustion by the added quantity of air furnished and the tur-
bulence produced during admission of the charge.
What is turbulence?
Ans. The state of being in violent disordered commotion.
What is the object of turbulence?
Ans. Designers aim to secure this action to more efficiently
mix the incoming charge with the air of combustion.
The turbulence due to air injection constituted to smooth and
regular fuel combustion, so that such engines usually can use a lower
grade of fuel.
What is airless injection?
Ans. In this system, fuel is drawn from the main tank by a
fuel supply or transfer pump, filtered and delivered to an
auxiliary tank or direct to the injection pump. The injection
pump forces the liquid at very high pressures through the
nozzle or spray valve into the cylinder at a pre-determined
time and quantity as controlled by timing and metering
mechanisms.
1372
Diesel Engines
›
CAM
TO OPEN
ell
TUGURIS
……ANCI……***
***ÜMÜNE
MECHANICAL SPRAY VALVES
SPRING
TO CLOSE
COMUNE
•MIMMIE
FUEL LINES
COMMON RAIL
[
:
MASTER
FUEL PUMP
IRWI
1500012013an -
FUEL TANK CONNECTION
Fig. 15.-Elementary master pump or common rail fuel system. This is a so-called constant pressure system
and requires mechanically operated spray valves.
T

Diesel Engines
1373
:
Name the several systems of airless injection.
Ans. 1, master pump; 2, individual pump; 3, distributor;
4, injector.
No. 1. Master Pump System
What is the principle of the master pump system?
Ans. The use of one pump to supply fuel to all the cylinders.
Describe the master pump system.
Ans. The pump maintains a high fuel pressure in a common
manifold or "rail" (hence the name "common rail system"), as
in fig. 15. Connection is made from the rail to each injection
nozzle. The injection nozzles are closed by spring loaded valves
which are opened by a separate mechanism or valve gear at the
proper time.
How is the power output controlled in the master pump
or "common rail system”?
Ans. Either by: 1, variation in the length of time the injec-
tion valve is held open; or 2, by variation in the fuel pressure
at the nozzle.
How are the injection valves operated?
Ans. Usually by cams either directly or through push rods
and rocker arms.
Mention one characteristic of the system.
Ans. In common rail systems the injection valves are always
under full pump pressure.
1374
Diesel Engines

HIISIISI
(MISHEFFE).
HYDRAULIC SPRAY VALVES
SPRING
TO CLOSE
PASSATISHI'
·HASIBUSHI
HYDRAULIC
PRESSURE
TO OPEN
DESSEURSHI
at
INDIVIDUAL
FUEL PUMPS
JESSEENESSM
'ESIGESTIM
↑
HIGH PRESSURE
FUEL LINES
-COMMON FUEL SUPPLY PIPE
Fig. 16.-Elementary individual pump fuel system. The pumps are of the metering type and supply fuel charges
to hydraulic spray valves.
Diesel Engines
1375
F
What is the chief advantage of the common rail system?
Ans. Simplicity, all that is required is: 1, single plunger
pump; 2, single spray valve for each cylinder; 3, mechanical
timing gear for operating the valve.
+
What pressure is maintained by the master pump?
Ans. From 2000 to 8000 lbs. per sq. in. depending upon the
design of the system.
No. 2. Individual Pump System
What is the principle of the individual pump system?
Ans. In this system a separate pump is used for each cylinder,
as shown in fig. 16.
How are the pumps mounted?
Ans. Either in a single housing or individually on each
cylinder. However, they are usually placed in a single housing.
Describe the pumps.
Ans. They are of the plunger type and work at pressures of
from 1000 to 10,000 lbs. per sq. in.
How is metering and timing accomplished?
Ans. Metering of fuel and timing of injection is done within
the pump unit, the pump of each cylinder discharging through
its connecting line and injection valve at the proper time.
Describe the injection valvės.
Ans. They are usually spring loaded, opening and closing at
a definite pre-determined pressure in order to insure spray
characteristics and accurate cut off of fuel.
1376
Diesel Engines
HYDRAULIC SPRAY VALVES
SPRING
TO CLOSE
HIGH PRESSURE
FUEL LINES
HYDRAULIC
PRESSURE
TO OPEN
We are
TO
HIGH PRESSURE
FUEL LINES
DISTRIBUTOR
METERING
HIGH PRESSURE
MASTER
PUMP
Fig. 17.-Elementary distributor fuel system. The distributor is a rotary multi-port valve and switches the fuel
charge delivered by the metering master pump to the several cylinders via hydraulic spray valves in proper
sequence.

Diesel Engines
1377
Why is this system called the hydraulic timing method?
Ans. Because the injection valve merely acts as a hydraulic
check valve, its opening depending upon the hydraulic pressure
built up by the pump at the proper time as shown in fig. 16.
Name three methods of metering the fuel.
Ans. 1, by variable stroke of plunger; 2, by throttling; and 3,
by variable by pass.
The variable by pass system is used on practically all modern small
and medium speed engines.
No. 3. Distributor System.
What is the principle of the distributor system?
Ans. The fuel is supplied by one pump and switched to each
cylinder by a multi-outlet rotating valve or distributor.
It may be compared in principle to synchronous ignition, so far as
the switching idea is concerned.
What should be noted about the distributor system?
Ans. The pump must make as many delivery strokes as there
are power strokes, and considering the heavy pressure, the
duty is severe and causes considerable wear, especially on high
speed engines.
This makes the system more suited to large slow speed engines.
What is the injector system?
Ans. This is virtually a distributor two stage pumping
system, that is, a modified distributor system.
1378
Diesel Engines
}
1
ܸܐ
Why was it introduced?
Ans. To relieve the metering pump of the severe duty of

A
CAM
TO OPEN
CHECK
VALVES
SPRING
TO CLOSE
RECEIVING
CHAMBER
TRANSFER
PASSAGE
INJECTORS
B
-DISCHARGE CHAMBER
-400418-
LOW PRESSURE FUEL LINES
TRANSFER PLUNGER
!
DISTRIBUTOR
.LOW PRESSURE
MASTER
PUMP
Fig. 18.-Distributor system with unit injectors illustrating A, Graham mechano,
acto transfer injector and B, reversed cone nozzle injector. These injectors are
opened by a cam and closed by a spring. The operation of the Graham
injector is described in the accompanying text. In the operation of the reversed
cone nozzle injector B, note the lever arm fulcrumed at the center, it will be
noted that when the nose of the cam pushes up one end of the lever, the
other end pushes down the valve stem to which is attached the pump plunger
and reversed valve of the nozzle, allowing the charge to enter the cylinder.
ך
I
1379
Diesel Engines
:
T
3
pumping against high pressure and to avoid high pressure
cubing lines.
What does the master or main pump do?
Ans. The main pump (sometimes called distributor pump)
meters the fuel and delivers it to the unit injectors at a low
pressure of about 10 lbs. per sq. in. After having passed through
a strainer the distributor functions to connect the unit injectors
· in proper sequence.
Where are they located?
Ans. In the center of each cylinder head.
it
Just what are these unit injectors?
Ans. They are small high pressure pumps and nozzle
combined.
Describe the drive.
Ans. They are driven by cam gear.
The plungers may be driven directly by cam shafts, rocker arms or
push rods or they may be spring loaded and ride upon the cams.
*NOTE.-Designed by the author.
Describe the Graham injector*.
Ans. It is described by its title: mechano, acto, transfer
injector and is shown at A in fig. 18. In operation, as the valve
closes the master pump forces (via distributor) a metered charge
of fuel, into the receiving chamber at low pressure. During the
opening of the valve, this charge is transferred to the discharge
chamber where it is pre-heated and discharged through the
multi-nozzle passages during the closing of the valve.
What are the features of the Graham injector?
1380
Diesel Engines
Ans. It requires no valve adjustment and no high pressure
fuel line.
Name three periods relating to combustion.
Ans. 1, delay; 2, uncontrolled combustion; 3, direct burnin
F
Combustion Periods
What do you understand by the delay period?
Ans. When the fuel is injected it does not start to burn
H
E
J

C
=
"UUUUUUU
H
B
-A
Fig. 19.-Raabe mechano-pneumatic injector. The parts are: A, fuel con-
nection; B, air connection; C, valve operating piston; D, shallow air groove
communicating with valve operating piston; E, injection timing port in injection
valve; F, rotary injection timing valve; G, timing port in injection valve;
H, air turbulence ports.
Diesel Engines
1381
immediately because the temperature of the finely divided fuel
must be raised to the ignition temperature of the fuel.
What other name is sometimes given to this period?
Ans. The time lag of ignition.
PLAIN
100% COMBUSTION VOLUME
·BOOK.
TANGENTIAL THROAT
MINIMUM
CLEARANCE
TURBULENCE
100% CHAMBER VOLUME


In
DISORDERED
CENTRIFUGAL EFFECT
Fig. 20.-Plain or so called "open" (?) combustion chamber. Adapted to
large slow speed engines. This type gives the minimum cooling surface exposed
to compressed air and flame. In small cylinders, ignition delay may retard
the ignition till a good portion of the fuel has been admitted, resulting in a
sudden pressure rise during the power stroke known as Diesel knock. Injection
in a plain combustion chamber is known as so called direct injection.
Fig. 21.-Turbulence combustion chamber. A 100% combustion chamber for
producing turbulence. In operation, the piston coming up on its compression
stroke forces the air through the port and into the chamber where it is compressed
to a pressure of approximately 550 lbs. per sq. in. The throat entering the com-
bustion chamber is tangent to its outer wall intended to force the air to swirl
at great speed around this wall and past the injection nozzle. In this way, it
sweeps the nozzle tip with air at all times during the compression stroke. Thi.
high speed swirling action of the air insures the prompt and intimate mixing
of the air and fuel, and since the rate of rotation increases with the speed of
the engine, it gives automatic compensation that permits high speed engine
operation attended with a clear exhaust and high power output. An example
of this type chamber is found on the Waukesha "Comet' engine.
1382
Diesel Engines
:
What is the uncontrolled combustion period?
Ans. Initial ignition takes place at the end of the delay
period and spreads to the rest of the charge. This progressive
combustion up to the instant of complete combustion is called
uncontrolled combustion.
What is the direct burning period?
PRE-COMBUSTION
30% VOLUME
101.
1
10% VOLUME
SEPARATE


H
-100% VOLUME
Fig. 22.-Pre-combustion chamber. Volume about 30 per cent giving partial
combustion. The object of this design is to obtain turbulence, higher wall
temperatures near the nozzle.
Fig. 23.-Separate combustion chamber. A 100 per cent volume chamber,
assuming zero clearance. Injection taking place at the remote end of the
chamber, complete ignition of the charge takes place before initial expansion
forces the burning gases through the small connecting passage.
Diesel Engines
1383
Ans. After the instant of maximum pressure, the fuel still
being injected finds the oxygen needed and the temperature
raised to such an extent that it begins burning immediately-
direct burning.
Combustion Methods
Name the multiplicity of auxiliary chamber designs upon
which the various combustion methods are based.
Ans. 1, plain (so called open)*; 2, turbulence; 3, pre-; 4,
separate; 5, ante-; 6, air cell.
What is a plain or so called "open" combustion chamber*?
Ans. A non-divided chamber being simply an extension of
the cylinder proper beyond the upper travel limit of the piston,
as in fig. 20.
Why is the plain combustion chamber undesirable on
modern engines?
Ans. Owing to the constant demand for more power and less
bulk, the rotative speed has greatly increased which necessi-
tated something different from the plain combustion chamber
for efficient combustion.
What is a turbulence air chamber?
Ans. A chamber designed, as in fig. 21, to provide turbulence,
so essential for efficient combustion in small high speed engines.
1
*NOTE. It would be difficult to understand the working of the fully disordered
brain that applied the word open in place of plain for this type of combustion
chamber, calling it an open combustion chamber. It is far from open, in fact, is
closed by a heavy head which must be very firmly bolted down, otherwise, that is
"or else" - especially during the power stroke with Diesel knock. The Greeks
had a word for this kind of nomenclature, idiotic.
1384
Diesel Engines
What is the construction?
Ans. The cylinder clearance is reduced to a minimum and
the turbulence chamber made large enough to receive practi-
cally all of the compressed air charge.
How is the turbulence obtained?
Ans. Varying degrees of turbulence are provided by the de-
sign of the chamber itself and the passage between the chamber
and the cylinder bore. After ignition in this chamber and
burning mixture passes through the narrow opening at great
velocity and on expanding in the cylinder a high degree of
turbulence is produced to mix the fuel and air.
What is a pre-combustion chamber?
Ans. This is a partial combustion chamber, as shown in fig.
22, in which combustion of a part of the fuel takes place. By
definition: A chamber so proportioned with respect to the clearance
volume proper of the cylinder that only about 30 per cent of the
combustion takes place within the chamber itself.
What is the function of the chamber?
Ans. To produce turbulence with partial pre-combustion.
What is a separate combustion chamber?
Ans. One in which all the combustion takes place in the
chamber itself: See fig. 23.
Describe the construction.
Ans. Cylinder clearance is reduced to a minimum. A small
passage leads to the separate combustion chamber.
Describe its operation.
Diesel Engines
1385
Ans. In operation, the entire charge is ignited in the separate
combustion chamber before the initial expansion takes place,
forcing the burning gases through the connecting passages and
against the moving piston..
What is the distinction between a pre- and a separate
combustion chamber?
Ans. The ratio between the cylinder clearance volume and
that of the combustion chamber.
These ratios are in per cent.
Pre-combustion chamber..
(C
Separate
ANTE
?
"
T
•
•
CHAMBER EXTENDED
BACK OF NOZZLE
AND PORT
.about 30%
.100% (assuming zero clearance)
AIR CELL


A. 1900)
ČESNÉLETA PAN
܀
NO FUEL ADMITTED
TO CHAMBER
1801:
Fig. 24.-Ante-combustion chamber. The object of this chamber is to supply
air progressively during the combustion period.
Fig. 25.—Air cell chamber. No combustion takes place in this chamber as the
injection nozzle located outside the chamber and injecting opposite the pistons
gives so called "direct injection." The practice of making air cell chambers
100 per cent volume is a doubtful expedient in the opinion of the author, as
the minute volume of air outside the air cell available for initial combustion
would perhaps become exhausted before piston advance produced sufficient
pressure drop to supply additional air required.
1386
Diesel Engines
What is an ante-combustion chamber?
Ans. A modification of the pre-combustion chamber. See
fig. 24.
By definition: A chamber so designed that injection takes place
directly opposite its outlet, the chamber extending backward from the
outlet.
What is an air cell chamber?
Ans. A chamber constructed as in fig. 25, in which only air
is compressed in the cell during the compression stroke, that is,
no combustion takes place therein.
Describe its operation.
Ans. In operation, fuel is injected only into the main cylinder,
during expansion of the burning gases in the main chamber,
when the pressure therein drops below that of the air in the cell.
Fuel Injection System
Of what does the fuel injection system consist?
Ans. 1, fuel transfer pump; 2, sediment trap; 3, strainer;
4, injection pump or pumps; 5, injection valves.
What is the function of the fuel transfer pump?
Ans. The low pressure transfer pump is used to deliver the
fuel from the tank to the injection pump.
What is placed between the transfer pump and the in-
jection pump mechanism and why?
Ans. A sediment trap and strainer because the fuel must be
separated from all impurities.
Diesel Engines
1387
I
Name two classes of injection pump and their uses.
Ans. 1, constant pressure (used with common rail system);
2, metering (used with individual pump system).
What other classification can you give for fuel pumps?
Ans. They are classed as: 1, constant stroke; and 2, variable
stroke.
What does a constant stroke pump do?
Ans. It delivers a definite quantity of fuel on each stroke.
Can the quantity be regulated and by what method?
Ans. Yes, by by-passing part of the fuel back to the supply
tank.
14
What is its application?
Ans. Automotive engines.
What is a variable stroke pump?
Ans. One in which the stroke is lengthened or shortened so
as to meter the correct charge to meet varying operating
conditions.
Name two general types of airless injection valves.
Ans. 1, mechanical; 2, hydraulic.
What is a mechanical injection valve?
Ans. One which is lifted from its seat by cam action driven
by the engine and closed by the action of a spring, as shown
in fig. 26.
What is a hydraulic valve?
1388
Diesel Engines
:
.
Ans. One held on its seat by a spring, as in fig. 27, and pro-
vided with an enlargement on the spindle so that impulse
pressure exerted by the metering fuel pump will overbalance
the tension of the spring and open the valve.

SPRING
TO CLOSE VALVE
FULCRUMS
CAM
TO OPEN VALVE
HALF SPEED CAM SHAFT
MV
CSPSSSSSSS
CORBELEZA
STUFFING BOX
HIGH PRESSURE FEED LINE
NEEDLE VALVE
MULTI PORT NOZZLE
Fig. 26.-Mechanical injection valve opened by cam drive and closed by
spring tension.
Name some types of fuel nozzles.
Ans. 1, single jet; 2, multi-jet; 3, pintle; 4, conical, as shown
in figs. 28 to 33.
What is a glow plug?
Diesel Engines
1389
Ans. A device which screws into the combustion chamber
like a spark plug and having a small heater coil. See fig. 34.

FUEL SUPPLY
SPRING
TO CLOSE VALVE
EXCESS AREA FOR
HYDRAULIC
OPENING FORCE
HIGH PRESSURE
FUEL LINE
NEEDLE VALVE
M
LETESESHI
METERING PUMP
Fig. 27.-Hydraulic injection valve opened by fuel pressure and closed by
spring tension.
!.
1390
Diesel Engines
ННННННН
What should be noted about poor compression?
нннннннн
IIII
CLOSED
Service


SINGLE-JET
NOZZLE
Figs. 18 and 29.-Single and multi-hole nozzles.
ННИИН
QTHE
MULTI - JET
•
NOZZLE


НІНН
OPEN
Figs. 30 and 31.-Pintle nozzle in closed and open position.
Diesel Engines
1391
Ans. There is a certain critical point of compression below
which a Diesel will not ignite the charge.
What causes loss of compression?
Ans. Leakage.
High compression pressure introduces an increased tendency for air
to leak through the smallest crevices.
What precaution should be taken in fitting piston rings?


PINTLE
VALVE
NO-
SPREAD
CYLINDRICAL
DISCHARGE
FUEL DUCT
REVERSED
CONE VALVE
WIDE
SPREAD
CONICAL
DISCHARGE
Figs. 32 and 33.-Comparison of pintle and conical valves.
Ans. The mechanic should be guided by the clearance recom-
mendations of the manufacturer.
Name another important cause of compression loss.
Ans. Leakage through the valves.
1392
Diesel Engines
Give Raabe's method of grinding injection valves.
Ans. According to Raabe (noted authority on Diesel engines):
“Whenever it is necessary to use any abrasive material, be
sure it is of extra fine grain and of uniform consistency."
...
"Ground glass mixed with light oil is best, but care must be taken
to remove any coarse grains from the powder. The abrasive must be
applied to the surface to be ground very sparingly, and very little
pressure should be applied while grinding.

MANUAL
SWITCH
&
GLOW
INDICATOR
SERIES GLOW PLUGS
BOTH TERMINALS ARE
INSULATED.
12-VOLTS
Fig. 34.-Glow plug circuit diagram for six cylinder engine.
ནབ
"When the surface has acquired a strictly uniform dull color, as
revealed by frequent examination, the abrasive must be wiped off very
carefully. A drop of light oil is then applied to the surface, and with
hardly any pressure the grinding is repeated. This latter operation
tends to remove any broken down grains of the abrasive that may
have been crushed into the pores of the metal.
"Moreover, the microscopic chips of metal which have been cut from
the surface by the abrasive will be removed. After a few light rubs
with pure oil, examine the surface. Repeat grinding and examine until
Diesel Engines
1393
yo
final examination reveals no further evidence of metallic or abrasive
particles upon the surface or in the film of oil upon it."
What precaution should be taken?
Ans. Use extreme precaution to prevent any abrasive re-
maining in contact with any bearing surfaces of valve guides
or pump barrels and plungers.
What should be done after over-hauling and re-assem-
bling any of the fuel handling apparatus?
Ans. Be sure it is cleared of air as air pockets in the fuel
system always cause trouble.
How about the idiotic practice of idling the engine?
Ans. Do not allow the engine to idle any more than is
absolutely necessary, and do not try to reach the minimum
speed at which the engine will idle.
Diesel Operating Instructions
STOPPING THE ENGINE
1. Stopping is generally affected by pulling the dash control
out until engine stops.
2. If atmospheric temperature be below freezing and no anti-
freeze solution be used the complete water circulating system
should be drained. This includes engine water jackets, water
pump, radiator if used, and all water pipes.
3. If anti-freeze solution be used the solution should be
checked with a hydrometer to make sure the solution will not
freeze. It is best to have a solution that will not freeze at tem-
peratures far below those then being experienced.
4. Do not fill batteries with water when shutting down as this
1394
Diesel Engines
makes them more liable to freeze. Fill batteries just before starting up
for the days run.
NOTE-If engine be kept in a warm storage or be located in a warmed building where
freezing is not liable, paragraphs 2, 3 and 4 may be disregarded.
CAUSES AND REMEDIES
Smoke in Exhaust.-The brown or black color in exhaust is
pure carbon-one of the elements of the fuel, the other being
hydrogen.
Where combined they form liquid oil or gas which may be perfectly water
white or clear in the case of oil and invisible in the form of gas.
These minute particles of carbon are solid substances and black. Their
presence in the exhaust gases makes it appear as dark or black smoke. The
more carbon particles, the darker color the exhaust ranging from a very
light grey haze to brown and even black smoke. The cause is incomplete
combustion. Since combustion is never complete, it is not presumed that
exhaust gases will be invisible. Smoke from the exhaust either brown or
black is not itself mechanically harmful to the engine but may indicate
corrections that should be made particularly if an increase of smoke appear
with no change in conditions such as load, speeds, temperatures, change of
fuel oil, or engine taken to higher altitude.
Increase of Brown or Black Smoke in Exhaust Gases.
Cause 1. Leaky cylinder head gasket.
Remedy
Cause 2. Leaky valves.
Remedy
Regrind.
Cause 3.
Remedy
Remove and clean or replace from spares.
Cause 4.
Remedy
Improper fuel oil.
Change fuel to brand with good ignition and burning qualities.
Dirty spray nozzles.
Clean.
Diesel Engines
1395
a v spre
Cause 5. Fuel injection timing too early usually accompanied
with "Fuel knocks" or "noisy engine."
Adjust timing of injection.
Remedy
Cause 6. Fuel injection timing too late accompanied with loss
of power but smooth and quiet running engine.
Adjust timing of injection.
Remedy
Cause 7. Leaky piston rings.
Remedy
Replace with new ones from spares
Cause 8. Fuel delivery valve in fuel pump stuck.
Remedy
Cause 9.
Remedy
Remove and clean with soft cloth. Do not use hard or sharp tools
or abrasives. They will spoil these parts. If valve cannot be made
to operate freely have replacement of new valve and seat assem-
bly made at a Bosch Diesel Service Station.
Fuel delivery valve spring in fuel pump broken.
Replace with new one from spares.
Cause 10. Fuel pump drive chain too loose.
Tighten and retime engine.
Remedy
KNOCKING IN ENGINE OR "FUEL KNOCKS”
Fuel knocks may come from one or more cylinders. If knocking
be from one cylinder:
Cause 1. Spray nozzle valve sticking from dirt or corrosion.
Remedy
Clean valve with a cloth (not abrasives) and clean body with
piece of wood. Turn valve stem in body until free, then smear
with good clean engine lubricating oil or vaseline and replace.
1396
Diesel Engines
+
Cause 2. Spray nozzle spring broken.
Remedy
Cause 3. Fuel delivery valve in pump stuck open from dirt or
corrosion.
Remedy
Cause 4.
Remedy
Remedy
Replace complete holder from spares. Never attempt to change
nozzle springs in field as they must be accurately calibrated with
instruments, at the factory.
Cause 6.
Remedy
Clean valve stem with cloth and valve seat with small piece of
wood. Do not use abrasives or metalic tools they will spoil these
delicate parts.
Cause 5. Inlet or exhaust valve not seating properly from
sticking or in need of grinding.
If necessary, replace with new valve and seat at Bosch Diesel
Service Station.
Remedy
Broken delivery valve spring in fuel pump.
Replace from spares.
- 4x2
Free valve with alcohol or other oil such as kerosene or clean
fuel oil or gasoline. Grind valve if necessary.
Leaky cylinder head gasket.
Clean or replace from spares.
If "fuel knocking" be in more than one cylinder and erratic
and intermittent:
Cause 1. Improper fuel. Has poor compression ignition quali-
ties.
Add equal parts or more if needed of fuel oil with good ignition
qualities or change fuel to a brand having good ignition and
burning qualities.
Diesel Engines
1397
Cause 2.
Remedy
Cause 3.
Remedy
Remedy
Sticking nozzle valve. This comes from dirt in fuel
oil or corrosion of these parts from acid in the fuel
oil.
Dismantle and cleanse the parts and also fuel strainers. If parts
be corroded change fuel to a brand acid free and install nozzle
and barrel if necessary.
If "fuel knocking" be in all cylinders continuous and steady, it
is usually accompanied with dark smoky exhaust:
Remedy
Water in fuel oil. "o
Drain fuel oil strainer sump and fuel tank of all water and
sediment.
Cause 1. Improper fuel oil has poor compression ignition
quantities.
Change fuel to brand of suitable combustion ignition qualities
or add equal quantities cr more if needed of fuel oil with good
compression ignition qualities.
Knocking from Mechanical Causes may be from several
sources among which are:
Cause 1. Pistons hitting inlet and exhaust valves from using
improper gasket.
Use only those supplied by manufacturer of the engine.
Cause 2. Pistons hitting exhaust and inlet valves from bear-
ings badly worn.
Replace with new bearing shells.
Remedy
Cause 3. Valve tappet clearance too great.
Adjust clearances.
Remedy
1398
Diesel Engines
Cause 4. Badly worn bearings either main or rod, or both.
Adjust or replace with new bearing shells.
Remedy
Cause 5.
Remedy
Cause 6.
Remedy
Badly worn piston pins or bushings, or both.
Replace with new.
Badly worn pistons or liners, or both.
Replace with new.
Cause 7. Loose fly wheel.
Remedy
Tighten.
There are many other mechanical causes of knocks which must be found
and remedied, but it is impossible to list all of them. If impossible to de-
termine what the trouble is after a thorough investigation, it is best to have
a factory trained expert investigate and remedy the trouble.
POINTS BY RAABE
The Practice of Idling.-It should always be remembered if
it were not for the heat of compression there would be no Diesel
engines. Accordingly and evidently, the slower the engine is run
the less the maximum temperature of compression.
Finally the speed may be reduced to such a point that the
maximum temperature of compression is not high enough to
ignite the charge with the result that the engine will "miss,"
that is, ignition will not take place.
:
1399
Diesel Engines
1
Since missing due to heat loss is mostly the result of idling at too low a
speed and for too long a period, the power loss is a minor factor when com-
pared with the other troubles arising from misfiring.
According to Raabe: Even at the temperature where the air
is too cool to ignite the fuel spray the entire confined space of
the combustion space, metal and all, is still at a blistering heat,
which condition tends to cause major troubles.
Into this heated chamber the fuel pump delivers charge after charge,
none of which is burnt. Yet the temperature is sufficiently high to separate
the volatile matter from the solid particles, which, due to their finely divided
state, are held in suspension in the best of fuel oils. Much of this solid mat-
ter is not expelled through the exhaust valve. It will collect upon the metal
surfaces, especially the cylinder walls, where even the slightest film of oil
will offer the binder which promotes adhesion. The heat then, even at the
reduced temperature, does the rest. It will bake the unsavory composition
into a tarry deposit which defies even the wiping action of the piston rings.
In fact, that part of the deposit which the rings succeed in scraping off will
find its way between rings and grooves where it will bake into a cement
which, once well solidified, will defy the efforts of the most skilled mechanic
trying to remove the rings intact.
The surface of the piston skirt, too, will receive a generous coating, and
in the course of time cylinder walls and piston will have the appearance of
well polished black walnut. The tarry matter, however, will not confine its
mischief to the combustion space, cylinder and piston. Some of it will cling to
the exposed part of the injection valve where again during subsequent igni-
tions, when the cylinder is firing due to speeding up, it will be baked to a car-
bon, the hardness of which almost equals that of carborundum.
Again, some of the tar; which term best describes the mess, will get past
even the best fitting rings and pistons, into the crank case. There it will
find some stray lubricating oil as an ally, and the combination, well stirred
by the cranks and connecting rods, will be beaten into a paste which, if not
caught in time, fills the crank case until the only free spaces within are the
cavities where the moving parts have cut their tracks. That such a condi-
tion is not particularly helpful to the engine's lubricating system needs
hardly any comment.
These troubles should not be regarded as a fault of the
engine, but a fault of the operator, who, either through igno-
rance or carelessness does not take the proper precaution to avoid
1400
Diesel Engines
E
them, namely: Do not allow the engine to idle any more than is
absolutely necessary, and do not try to reach the minimum
speed at which the engine will idle.
Remember that, whether the engine receives its full charges of fuel, for
full power, or its minimum charges for minimum power, the tempera-
ture necessary to ignite the charge is the same, and in a small cylinder,
where the air is compressed into a very small space, the "fast leaking" heat
has but a short distance to travel to make its escape through the water
jacket to the radiator.
If an engine begin to miss when idling and the missing
cylinders pick up their cycle on speeding up, there is no fault
with the engine, but if the missing continue, it indicates fuel
pump trouble.
ï
Overloading. When taking a steep hill, and the engine
shows signs of laboring hard and slowing down, shift gears. To
almost stall the engine with an overload is as bad as to almost
stall it while idling. In fact, it is worse.
If one of the cylinders quit, the fuel pump will regardlessly give it its full
charge. That means there is much excess oil going through unburnt, doing
its mischief.
Lubricating Oil.-Due to the differences in viscosity of
different brands of oil at the same temperatures and the
difference in crank case temperature in engines on different
types of service, it is impossible to give a definite S.A.E. num-
ber of oil to use in the engine crank case.
:
A visco meter, such as shown in fig.35, indicates the viscosity of the lu-
bricating oil during the actual operation of the engine and this gauge should
be used in determining what brand and grade of lubricating oil to use.
To select the proper oil, obtain an oil which comes within
recommended physical specifications and try in the engine.
Diesel Engines
1401
*
Start the engine and observe the indicating hand on the visco meter
gauge. A proper oil should first move the indicating hand to the right close
to or into the high section on the dial when oil is cold.
As the oil warms up the hand should move to the left gradually until it
reaches a position approximately as shown in fig. 35.-which is almost to the
"low" or "stop" line on the gauge when the oil is at normal crank case tem-
perature. The oil should stay at the viscosity represented by this location
of the indicator hand as long as the engine is operating. If this hand drop
from this location after a relatively short run it indicates the viscosity has

OIL
SUPPLY
LOW NORMAL
OIL
VISCOSITY
ISCO-METER
GAUGE TUBE.
CLEANING PLUG
CORP
BUTI
HIGH
GAUGE.
LORIFICE
FILTER SCREEN
AUTOMATIC
CONTROLLED
CHAMBER
AUTOMATIC
UNLOADING
VALVE
RESISTANCE
TUBE
Fig. 35.-Viscometer for testing lubricating oil under operating conditions.
dropped-oil has thinned, to a point of danger and the engine should be
stopped immediately and oil changed to another brand or heavier grade
until a suitable oil is found.
If, after the engine is operating and the crank case temperature has risen
to normal, the indicating hand do not drop into a position somewhere in the
last three graduations above the "low" or "stop" line on the gauge, the oil
is too heavy and should be changed to another brand or lighter grade.
1.
1402
Diesel Engines
Do not select lubricating oil because it has certain S.A.E.
number as certain brands of oil of S.A.E.
No. 20 may not have the lubricating characteristics necessary for the
particular type of service, but another brand of S.A.E. 20 mày, due to one
being at the top extreme limit and the other at the lowest extreme limit or
at different points between these extremes.
One brand of S.A.E. 20 may give the same satisfactory results as another
brand of S.A.E. 30 or with another brand, S.A.E. 40 may be necessary—
always select the brand and grade of lubricating oil by its operation in the
engine, in the type of service to be encountered, by the visco meter and not
by price or physical characteristics of S.A.E. number. The indicator hand
shows what the oil is doing in the engine at all temperatures and the lubri-
cating oil should be selected by what this hand indicates.
AIR
(
2


AIR
AIR
19
Fig. 36.-G. M. two stroke cycle. 1. Piston at lower end of scavenging and
compression stroke. Air entering through port to combustion chamber.
Fig. 37.-G. M. two stroke cycle. 2. Exhaust valves and air ports closed. Air
being compressed.
Diesel Engines
1403
AIR
Two Cycle Diesel Engines
(With Super-charger)
What is a two cycle engine?
Ans. One in which the four events of the cycle, namely:
Charging, compression, explosion and exhaust, are performed
during two strokes of the piston.


FUEL
AIR
EXHAUST
I
Fig. 38.-G. M. two stroke cycle. 3. Beginning of power stroke. Charged fuel
being injected into combustion chamber.
Fig. 39.-G. M. two stroke cycle. 4. Completion of useful part of power stroke,
exhaust valve open, preceding opening of air ports. Exhaust taking place and
cylinder about to be swept with clean scavenging air.
What are the advantages of the two cycle engine as com-
pared with the four cycle engine?
Ans. Saving in weight and space, and better power flow.
How is the engine constructed for two cycle operation?
Ans. A series of ports (cut into the circumference of the
1404
Diesel Engines
:
cylinder wall above the piston in its lowest position), admits
the air from the blower into the cylinder as soon as the face of
the piston uncovers the ports.
What happens as the piston continues on the upward
stroke?
Ans. The exhaust valves close and the charge of fresh air is
subjected to the final compression.
Shortly before the piston reaches its highest position the required
amount of fuel is sprayed into the combustion space, and the intense
heat generated during the high compression of the air ignites the fine
fuel spray and combustion continues as long as the fuel spray lasts.
*
FULL LOAD
(THEORETICAL)
INJECTION BEGINS
EXHAUST CAM
LIFT ENDS
EXHAUST VALVE CLOSES
2008 VALVE LASH
ROTATION OF ENGINE
FROM FRONT END

#19°
IN. CLOSES
T. D. C.
INJECTION ENDS
ALSO ZERO FUEL
94½º
IN. OPENS
135°
9gć
EXHAUST CAM
LIFT BEGINS
61½
EXHAUST VALVE OPENS
.008 VALVE LASH
Fig. 40.-G. M. Diesel timing diagram for 3, 4 and 6-71 engines.
*-* - . • .
Diesel Engines
1405
What occurs now?
Ans. The resulting pressure forces the piston downward until
the exhaust valves are again opened, at which time the burnt
gases escape into the exhaust manifold and the cylinder volume
is swept with clean scavenging air as the downward moving
piston uncovers the admission ports.
Operating Instructions
GM-71 Diesel Engines
Starting the Engine
The engine is started by means of a motor which is supplied with electric current from a
storage battery. The specifications of these units will be supplied with each engine.
Starting a New Engine. Before attempting to start a new engine, carry out the following
operations:
1. Fill the crankcase with specified quantity of the recommended lubricating oil.
2.
Fill the fuel tank with the proper fuel oil.
3
3. Fill cooling system with clean soft water (see remarks under "Cooling System,"
if an anti-freeze solution is used.
4. Make sure that engine throttle is in the "stop" position.
5. Turn engine over a couple of revolutions to clear piston head of any possible water
or surplus oil accumulations, which if present in any great quantities, might seriously
damage the engine. The clearance between the piston top and cylinder head is so
small that a small amount of water on the piston might seriously damage, if not wreck,
the engine.
6. Open the throttle from "stop" to "idle" position and start engine by operating the
starter button.
7. Operate the engine on part throttle until warmed up before picking up load.
8. Completely open the throttle at the same time full load is applied.
1. Check the fuel supply.
2. Check the oil level.
Usual Routine Engine Starting. If the engine has been operating recently and no parts
removed or repairs mode since last operated, the following will apply to starting the
engine:
1406
Diesel Engines
3. Check the water in the cooling system.
4. Inspect engine to see that no one has tampered with any of the outside mechanism,
5. Open the throttle from "stop" to "idle" position and start the engine by operating
the starter button.
6. Operate the engine at part throttle three or four minutes, before picking up load.
7. Completely open the throttle at the same time full load is applied.
Cold Weather Starting. When starting any internal combustion engine in cold weather
a large part of the energy of combustion is absorbed by the pistons, cylinder walls, cooling
water and in overcoming friction.
Under extremely low outside temperatures the cold oil in the bearings and between the
pistons and cylinder walls creates very high friction and the effort to crank the engine is.
much greater than when the engine is warm.
In the Diesel engine, the only means of igniting the fuel sprayed into the combustion cham-
ber, is the increased temperature due to compressing the air. This temperature becomes
high enough under ordinary operating conditions but may not be sufficiently high at extremely
low outside temperatures to ignite the charge.
Under these unusually cold conditions, therefore, some external means of warming either
the ingoing air or the cooling water or both may be necessary.
The following hints will be found helpful when starting the engine in cold weather.
Starting Engine at outside Temperatures between 50° F. and 32° F.
1. Check fuel supply and oil level.
2. If the temperature linger around 32°F., time will no doubt be saved by draining the
cooling water and substituting warm water.
3. Open the throttle from "Stop" to "Idle" position and start engine by operating the
starter button.
4. Operate the engine on part throttle until warmed up before picking up load.
5. Completely open the throttle at the same time full load is applied.
Starting Engine at Outside Temperatures Between 32° F. and Oº F.
1. Check fuel supply and oil level.
2. Fill the cooling system with warm anti-freeze cooling solution. 'Note: Do not use a
cooling solution hotter than 180° F. A boiling solution poured into the very cold cylin
der block might crack the block.
·
3. Open the throttle from "Stop" to "Idle" position and start engine by operating the
starter button.
Diesel Engines
1407
4, Operate the engine on part throttle until warmed up before picking up load."
5. Completely open the throttle at the same time full load is applied.
Starting Engine at Outside Temperatures between 0° F. and Below
1. Check fuel supply and oil level.
2. Fill the cooling system with warm anti-freeze cooling solution. Note: Do not use
a cooling solution hotter than 180° F. A boiling solution poured into the very cold
cylinder block might crack the block.
3. Fill engine crankcase to "Full" mark on gauge stick with hot oil. Note: Use extreme
care in heating either lubricating oil or volatile anti-freeze solutions over an open
flame to guard against fire.
4. Open the throttle from "Stop" to "Idle" position and start engine by operating the
starter button.
5. Operate the engine oil on part throttle until warmed up before picking up load.
6. Completely open the throttle at the same time full load is applied.
Operating Instructions After Starting Engine
After engine has started, run for three or four minutes at part throttle and inspect
engine to see that all parts are functioning properly.
2. Look at oil gauge which should register between 25 and 35 pounds under normal
operating conditions.
The oil gauge may show no pressure for 10 to 15 seconds after the engine starts
with cold oil. If, however, no pressure show on the gauge in this length of time,
shut engine down and locate the trouble.
Lack of oil pressure may be due to:
(a) lack of oil.
(b) Inoperative oil gauge.
(c) Broken gauge line.
(d) Improper functioning oil pump.
(e) Improper functioning oil pump drive.
(A) Plugged oil lines.
(g) Dirty oil filter in conjunction with inoperative by-pass valve at filter.
th) Clogged oil pump inle: screen.
1408
Diesel Engines
3. Check water circulation. If water temperature gauge show. "Hot," shut engine
down and locate the trouble.
Over-heating of the cooling solution may be due to:
(a) Plugged or dirty radiator.
(b)
Loose or broken fan belt.
(c)
Inoperative thermostat at outlet of cylinder head to radiator.
Caution: Never operate the engine with the cooling solution boiling.
4. After the engine has warmed up, the operation should be smooth and the exhaust
reasonably free from smoke. Should the engine operation be uneven, indicating
a "weak" cylinder, check
5. Lubricate generator after each 24 hours of operation.
6. Clean lubricating oil filter
7. Keep the fuel supply clean and clean the fuel filter often. This is important and
will perhaps avoid trouble to engine injectors later.
8. Service air cleaner
Too much stress cannot be laid on
the importance of regular attention to the air cleaner where the engine is operating
in dusty surroundings.
9. Observe fan belt for tension. A V-belt should be neither too tight nor too loose.
Too tight a belt imposes an undue load on the belt itself when the engine is sud-
denly stopped. Too loose a belt will permit slippage, reduced fan speeds; and over-
heating. A good guide to follow for proper tension on the fan belt is when the
fan pulley can just be turned by hand from the fan blades.
10. See that radiator fins are kept free from any obstructions that might restrict the
air flow.
11. See that the storage battery is kept filled with water and that generator charging rate
is such as to keep battery fully charged at all times. (See Manufacturer's Instructions
for Battery Care.)
12. Do not race the engine with no load.
Stopping the Engine
1. When stopping the engine first release the load and at the same time partially close
the throttle. Completely closing the throttle will stop the engine.
2. If the outside temperature is apt to drop below 32° F., be sure a suitable quantity of
anti-freeze solution is in the cooling water to prevent freezing.
If the outside temperature ranges between 32° F. and 0° F., drain the liquid from the
cooling system after stopping the engine, whether or not an anti-freeze solution is used.
Should the outside temperature range around 0° F., the labor of starting the engine will
Diesel Engines
1409
་
be much lessened if the cooling solution is warmed before starting the engine. See
"Starting Engine at Outside Temperatures between 32° F. and 0° F.",
If the outside temperature ranges between 0° F. and below, drain the liquid from the
cooling system and the oil from the crankcase after stopping the engine, whether or
not an anti-freeze solution is used. Should the outside temperature drop below zero,
the labor of starting will be much lessened if the cooling solution and the lubricating
oil is warmed before starting the engine.
3. When an anti-freeze solution is used, the solution should be frequently checked with
hydrometer to make sure the solution will not freeze.
4. If engine is exposed to the elements, protect the entire installation with a water-proof
cover.
5. If engine is to remain idle over an extended period of time, carry out the instructions
under "Storing Engine for Long Periods"
Care of Engine
Dirt is the worst enemy of any internal combustion engine. Therefore, too many pre-
cautions cannot be taken to exclude this menace from your power plant. Dirt may find
its way into the combustion chambers through the air system, into the crankcase oil through
the breather intake, and into the fuel system from fuel tank, unless the necessary precautions
are taken by installing and keeping clean the necessary air cleaners and filters.
An efficient air cleaner should be used and properly serviced as directed by the manu-
facturer. Where the engine is set up in very dirty air surroundings, too many precautions
cannot be taken to exclude dirt from entering the engine through the air intake system.
Clean Fuel Oil. Too much importance cannot be placed on the necessity of keeping the
fuel oil clean. Care should be taken to exclude dirt from storage tank, pumps, etc. The
necessary fuel filters should be installed in the fuel line and these filters kept clean at all
times. See "Fuel Oil Filter,"
Care of Cooling System. Keep your cooling system clean and filled. The use of soft water
in the cooling system will prevent lime deposits in the cylinder block and obstructions in the
radiator care.
When the engine is to be stored for long periods of time, the cooling system should be
drained. If the engine is installed in dirty surroundings, an occasional flushing of the cool-
ing system is advisable. Necessary precautions should be taken to exclude lint and foreign
matter from being drawn into the radiator fins and closing off partial air circulation through
the radiator core
1410
Diesel Engines
Where the outside temperature is apt to drop below freezing, anti-freeze solution should
be used to avoid damage to the engine.
Do not allow leaks in the cooling system, or the water in the cooling system to get low or
boil. Over-heating not only breaks down the oil film, but is apt to cause serious damage
to the engine.
Check the anti-freeze solution every night when closing the engine down, to be sure that
the strength of the solution is such as to protect the engine.
Lubrication. Change engine oil as directed under "Lubricating Oil Recommendations,"
Service oil filter as directed under "Cleaning Lubricating Oil Filter,"
Storing Engine for Long Periods. If the engine is to be idle for a month or more, special
precautions should be taken to protect the engine to avoid rust accumulations on the wear-
ing surfaces or in the fuel system.
When storing the engine, remove all injectors, and store them in clean fuel oil. Use a
clean container with a tight cover and have all injectiors immersed in the oil. If any injec-
tors need repairs or service, make such repairs before storing the injectors, then they
will be ready for use when again needed.
J
After removing injectors, crank engine over a few revolutions to oil cylinder walls.
Drain the crankcase engine oil and oil filters and replace all drain plugs. Clean oil filter
before storing the engine.
Drain and flush out the complete cooling system. Be sure that all water is drained from
cylinder block, water pump and oil cooler as well as the radiator.
Be sure the storage battery is fully charged, then store in a dry place where the tem-
perature is above 32° F.
Diesel Engine Performance
1411
CHAPTER 63
THERMO-DYNAMIC AND OTHER CHARACTERISTICS
OF
DIESEL ENGINES
COMPARED WITH THE OTTO CYCLE
ALSO
THE FALLACY OF COMPOUNDING
A critical comparative analysis of Diesel engine performance,
written for this book at the request of the author by Capt. Henry E.
Raabe, M. E. inventor and noted authority on Diesel engines.
The value of the Diesel engine is being decidedly over--esti-
mated. Technically it falls quite short of the popular conception:
that it is "the last word" on internal combustion engineering.
In fairness the definition of the system might read:
A cumbersome way of igniting the charge of fuel within the com-
bustion chamber of an internal combustion engine.
That is about all.
The Diesel engine ignites its fuel spontaneously, by the heat
of the highly compressed air. Thus it requires no igniting ap-
paratus. Is the saving of this simple device worth the encum-
brance of so much extra weight, and the excessive pressure?
But the popular conception that it is the Diesel system
which has made possible the use of the heavier hydrocarbons
1412
Diesel Engine Performance
where gasoline has held sway for over a generation is erroneous.
The heavier hydrocarbons can be used in engines of the Otto
cycle.
Those who dispute this should shake hands with the Diesel engine
"expert" whose answer to a fair question was: "You can't use gasoline
in a Diesel engine. If you ever try it the whole motor would just fly
to pieces. Gasoline is too explosive " Well, he was an expert! But more
about this presently.
Now, there have been successful oil engines on the market
before John Q. ever had heard of the name of Diesel. And some
of them could "get away" with fuel oils so heavy that builders
of Diesel engines would not dare to try them in their engines
even as an emergency diet. And they ran with low fuel con-
sumption too
One type of engine in particular, which is perfunctorily
described in Audel's Automobile Guide, by F. D. Graham, M.E.,
pages 1464-1466, had a very unique direct injection system
with spark ignition.
In a test made by Mr. Graham, the writer, and other prominent
engineers it developed a horse power per hour on as little as .32 pound
per horse power of a very heavy forge furnace oil of non-descript
gravity, almost black in color, and other characteristics which would
make Diesel engineers do some tall head-scratching before they would
venture to even try to use it.
Why is there nothing heard of these engines any more.
Well, let the powers that control the wheels of our industries answer
that question, if they can-without their customary hems and haws.
The reason the Diesel engine has forged ahead so fast is
not because of its alleged economy in fuel consumption. As a
matter of fact, the Diesel system-igniting at constant pres-
sure-falls decidedly short of meeting the fuel economy of an
Otto cycle engine-igniting at constant volume-if we would
compare them at equal compression pressures.
Diesel Engine Performance
1413
That is: If we could compare a Diesel engine compressing to 400 psi
with an Otto cycle engine, also compressing to 400 psi, our test would
prove the Otto cycle engine just about twice as economical as the
Diesel.
Unfortunately for the Otto cycle we are restricted with our
compression pressures. If we go too high we are confronted
with the serious problem of spontaneous combustion, pre-
ignition, which is exactly what Diesels need to make the system
operative. Therefore we must tolerate the high pressures with
their attendant heavy weights.
However, the M.E.P.-the pressure which does the work
during the cycle-often falls below that of an Otto cycle gas-
oline engine of the ordinary commercial type, while oil engines
of the Otto cycle have shown M.E.Ps. way above that of
Diesels.
It should be borne in mind that mean effective pressure does not mean
the average of the total pressures throughout the stroke, but that the
average of the compression pressures has to be deducted from the
average totals. Yet, the motor has to be designed to withstand the
highest pressure obtained during the cycle.
In an Otto cycle engine a relatively slight rise in compres-
sion will effect considerable rise in final pressure, thus we gain
proportionately much more in our M.E.P. than with the Diesel
system, wherein the compression pressure and final pressure are
practically the same.
And if we design an Otto cycle oil engine to use a very high
compression, the consequent high M.E.P. obtained, with its
attendant high horse power will give us the full benefit of the
increased weight we have to put into the engine parts to with-
stand the high pressure. That such an engine is practical without
the annoyance of detonation has been demonstrated with the
engine using direct injection with spark ignition previously
referred to.
妥
​1414
Diesel Engine Performance
Now let us settle about the answer to the so often advanced
stupid question:
Can gasoline be used in a Diesel engine?
My answer is "Yes", because I have done it and "got away
with it". And that should outweigh a haphazard opinion of
even an "expert".
As a matter of fact, in my test, the indicator showed a ten-
dency to drop in pressure during the latter part of the period
of injection. Rather the opposite of the bunk about the motor
flying to pieces.
I ascribed the drop in pressure to the lower terminal value of gasoline
combined with reduced penetration and turbulence, due to the too
rapid vaporization of the highly volatile liquid coming in contact with
the highly heated dense air in the combustion chamber. This latter
fault naturally led to unsatisfactory combustion.
Here are the facts: Gasoline is no more explosive than oil.
What has made it the popular fuel for "explosive engines" is
its volatility, its propensity to vaporize at low temperature so
its vapour can be mixed with a suitable quantity of air, to form
a rapidly combustible mixture, while it is on its way to the
engine cylinders.
Naturally, this tendency to adapt itself to our wants so readily,
helped along by the observation of a few "back-fires", and the occas-
ional indoor sport of applying a torch to an "empty"gasoline tank
has assigned it to the category of "high explosives". But while it is
confined in a liquid state, and under pressure at that, it is as inert as
water or fuel oil. And that is exactly the way it is kept within the fuel
injection line of a Diesel engine.
Then, when the injection system releases it finally into the highly
heated air within the combustion space, it will vaporize and ignite,
just like injected fuel oil; which is exactly what we wanted. And since
the ignition pressure is really lower than with fuel oil, as stated before,
the potential suicide candidate will be disappointed through remaining
this side of Hades.
This, however, should be borne in mind: The use of gasoline
Diesel Engine Performance
1415
in a Diesel engine should be avoided by the lay for the following
reasons:
•
First of all, it is doubtful whether he will ever get his engine
started. For, under the high pressure the fuel pump valves,
which fulfilled their duty perfectly when using heavy oil, are
only too apt to "leak back" when called upon to seal against
the so penetrating gasoline. This failure, however, will mean no
more than disappointment to the experimenter.
But if the pump should be in such condition that it will work,
and actually bring the gas under high pressure, then look out
if there should be any leaky joints in the line!
If there should be an open flame even as far away as thirty feet from
the engine, a needle-like stream, which could even pierce your finger,
might reach it before the operator would know what happened. Then—
perhaps flowers and slow music
To grind pump valves or joints so as to withstand gasoline
under a few thousand pounds pressure is no job for the average
mechanic. There is no "good enough" to such a job, only a
perfect or a useless. But why "monkey" with gasoline at all
when your engine can use fuel oil.
The Fallacy of Compounding
As the popularity of the Diesel engine has gradually grown,
it has given rise to considerable speculation of potential im-
provements to augment the growth of its use. Most of the
often rashly suggested improvements are, of course, supposed
to increase its efficiency. Foremost among them is the question:
"Why shouldn't it be compounded to multi-stage expansion
like the steam engine?”
1416
Diesel Engine Performance
Now, it may appear peculiar that this subject is attracting so much
attention just now, while other internal combustion engines, which
have held the market for so many years, have remained wall flowers
with respect to this question.
I believe this latter question can be easily answered: It is compara-
tively recently that the internal combustion engine, in Diesel form,
has really become a competitor to large steam engines of multi-stage
expansion types. Thusly it had not come into the hands of operating
engineers who have had charge of compound or triple expansion
engines until it invaded the marine field to the extent of more than
pleasure boats. And to the operators of pleasure boats such matters as
compounding, etc., are something like Greek.
First of all let me say that there have been attempts made to
compound internal combustion engines.
And to those to whom the subject is Greek, let me say that
compounding means to use the exhaust gases in an additional
cylinder, of larger size than the first one, of course, instead of
letting them escape into the atmosphere.
The idea is to gain additional power out of the energy still remaining
in the exhaust gases, through further expansion in the larger cylinder.
In steam engineering we call this multi-stage expansion, because
each cylinder permits the steam to expand to a certain pre-determined
stage while doing its work expansively.
Now, in steam engineering we economize through this
practice.
For, if we should venture to expand high pressure steam from
its maximum pressure down to atmospheric, or even condenser
pressure, in the same cylinder to which it is admitted from the
boiler, the cylinder walls, piston, etc., having been heated to
live steam heat, would give up so much of this heat during
expansion and exhaust that too much of the steam, and its
useful heat, would be lost through condensation during the
next admission.
This would result in a great drop in the engine's efficiency. Therefore
we gain through expanding in "stages," either compound, triple or even
Diesel Engine Performance
1417
quadruple expansion. We even go so far as to prevent heat loss through
heat-jacketing our cylinders, and covering them.
Let it be understood that multi-stage expansion is bene-
ficial (in fact very much so) to the efficiency of a steam engine,
but does not the law of thermo dynamics effect the internal
combustion engine as well? Definitely, it does; but here we
deal with such high temperatures in direct contact with our
cylinder walls, pistons, etc., that we not only must refrain from
covering the heat-exposed metal against heat loss, but are act-
ually compelled to do something to avoid their over-heating
and subsequent destruction.
For that reason we either "water-jacket" or "air-cool" these parts.
Non-technically we might express ourselves with: "The two types of
engines demand exactly the very opposites."
This colloquialism is not exactly true, since we try our best to thus
waste as little of the heat as possible. But we simply cannot avoid
waste through cylinder cooling altogether, although there is nothing
to prevent us from using that "waste heat," often more than 40% of
the heating value of the fuel-for external purposes, such as heating
rooms, etc.
Now, does not the foregoing make it quite clear that there
is nothing gained in an internal combustion engine, through
multi-stage expansion?
By this I do not mean that the engine should not be designed so that
it will expand the products of combustion down to the atmosphere
before exhaust release takes place. Far from it; for, knowing that nature
has given us just so much fuel, which will be exhausted some day, I
am very much in favor of high thermo dynamic eficiency.
But the characteristics of the internal combustion engine are
happily such that we can go through our whole stage of expan-
sions in our "high pressure" cylinder-the cylinder in which
combustion has taken place.
And, since I ventured to the use of so un-technical a statement as to
say that the steam and internal combustion engines "demand exactly
1418
Diesel Engine Performance
the very opposites," I shall emphasize this assertion with the reminder
that, if the expanding gases cool down to such an extent, during the
latter part of the stroke, as to "rob" the cylinder walls, and other
highly heated surfaces, of some of their heat, then that "robbery"
automatically leads us onto the road to high efficiency, simply because
the heat thus absorbed is no other than some of the heat we had to
waste through cylinder jacketing. THUS, WE ACTUALLY ADD
THAT RECLAIMED HEAT TO THAT OF THE EXPANDING
GASES WHICH DO OUR USEFUL WORK!
And in large installations that incidental saving might save quite a
worth-while amount of red ink in the accountants' books at the end of
the year.
Now, while we are pursuing the efficiency bug, let us go back to the
subject of the water jacket of our cylinders. I made the remark that
the heat wasted there is often more than 40% of the total heat value
of the fuel consumed. In addition to this we "throw away" quite a
little heat with the exhaust gases, even if we expand down to atmos-
phere. Furthermore, mention was made that this "waste heat" can be
used for external purposes, such as heating, etc.
Well, would not this statement suggest something to the past.
designer of steam engines? Definitely it would.
I know, because many years ago, when the internal combustion
engine was more of a laboratory toy than a practical prime mover, I
raised steam in the jacket water, and boosted it to a pressure of 60
psi in a "booster Boiler" heated by the exhaust gases. This steam was
then used in the lower end of the internal combustion cylinder. And,
despite the fact that the engine was a rather crude piece of "cut and
try” job, the introduction of the "steam end" raised the efficiency of
the engine more than 3%. There is no reason to doubt that in a large
installation, carefully designed, a much higher percentage of saving
could be reached. For there was no cylinder condensation since the
heat of the metal, i.e., that of the cylinder walls and piston, consider-
ably exceeded the temperature of the steam. Thus the steam had the
tendency to act as an internal cooling agent upon the heated parts,
and with the introduction of a very small quantity of oil, by means of
a common steam engine lubricator, the steam solved the problem of
cylinder lubrication most admirably.
Of course, the piston had to be supplied with a piston rod which
worked through a stuffing box. The cross head and guides, which the
steam engineer so loves to watch perform their functions, also had to
be present. The whole machine "smacked of Engineering" to such
i
Diesel Engine Performance
1419
extent that it induced an enthused admirer to remark: "Now, that
looks like a real engine!"
Naturally, for small installations, such as motor boats, auto-
mobiles, etc., such refinements are out of the question. And in
the case of a large installation there is no reason why the
exhaust from the steam end of the engine could not be advan-
tageously used in a low pressure cylinder and exhausted into a
condenser, so as to add materially to the efficiency of the engine.
All this is of the long ago, and the patents which were obtained are
now mere dust-laden records for some one to revive when fuel gets so
scarce that wastefulness will be regarded a crime.
But as regards the modern commercial motor of vest-pocket size,
ground out of sausage machines by the million, to fit into the hands of
Tom, Dick and Harry. - Well, let us thank Nature for adjusting
the laws of thermo-dynamics so as not to have encouraged the com-
pounding of internal combustion motors.
S
Imagine the complications which compounding would add to the
metallic conglomerations of the modern mechanical onions-which the
greed for every cubic inch of space developed-so that the repair man
would have to "peel off" so many additional layers of parts before he
can get at the "innards" which need his attention.
Cycle or System
In practice we often speak of the Diesel system as the Diesel
cycle.
Now, this practice is either right, or it is wrong (a stupid statement
to make; isn't it?) After that I will have to vindicate my sanity with an
explanation. Well, here goes:
Whether the Diesel engine really stands in a "cycle class"
by itself, or whether it is merely entitled to a "system class,"
depends entirely upon the theme of our treatise or conversation!
Now, in internal combustion engineering we are confronted today
by but two distinct cycles: The "Two Cycle", correctly, two stroke
cycle, and the "Four cycle", correctly four stroke cycle.
1420
Diesel Engine Performance
The four stroke cycle is known as the Otto cycle, and the
two stroke cycle as the Clerk cycle.
Yet, to come right down to fine points, the so called Clerk cycle
encroaches upon the Otto cycle in the matter of ignition, which means
that it ignites at constant volume (explosively). So, if we speak of such
a thing as a Diesel cycle engine in contrast to a four cycle, or two cycle
engine, we are wrong.-Just about as much out of gear as to speak of
oil engines in general as Diesel engines.
So, remember this:
The only factor which distinguishes the Diesel engine from others
is the manner of igniting its fuel charge, which is, to ignite it "gradually"
during its injection into superheated air while the piston is embarked
on its power stroke. And this is being done with engines operating on
either the two stroke cycle, or on the four stroke cycle. Moreover, it
does not in the least affect the cycle what sort of injection valve and
pump system the builders are using, or what fancy name they call
their engines.
If one should be just "pink-headed" enough to persist in assigning
the Diesel engine to a cycle class, then he should go so far as to divide
his cycle into periods as follows:
For the four stroke cycle engine: 1, Suction; 2, compression;
3, injection-ignition; 4, expansion, and 5, exhaust period.
For the two stroke cycle engine: 1, Compression; 2, injection-
ignition; 3, expansion; 4, exhaust; and 5, scavenging period.
This makes five distinct "periods" for both cycles.
However, if we try to "show off" through being so technical, then
we must be also generous with the oil engines igniting at constant
volume, (which will "make their comeback" some day) and divide
their cycles also into periods. This means those operating with direct
injection with spark ignition. And (cheers for the latter) they would
go to the Diesel one better: With their injection period and ignition
period distinctly separate, they will class in the "six period cycle"
fraternity.
Lubricants
1421
CHAPTER 64
Lubricants
By definition, a lubricant is a substance used to reduce friction
by preventing direct contact of rubbing surfaces, the substance
being pressed out into a thin film on which the moving parts rub.
What should be noted in the selection of a lubricant?
Ans. A lubricant which would make a large shaft run smooth
and cool in its bearings might be quite unsatisfactory if applied
in some other place as for example, a light, high speed spindle.
What is friction?
Ans. The resistance existing between two bodies in contact,
which tends to prevent their motion on each other.
What causes friction?
Ans. It is partly due to the natural adhesion of one body to
another, but chiefly to the roughness of the surfaces in contact.
Why is direct contact objectionable?
Ans. Because metal surfaces, although they appear smooth
to the eye and to the touch, are made up of minute irregularities
which are visible when magnified, as shown in fig. 1.
How do these irregularities act?
1422
Lubricants
Ans. When two metal surfaces are brought into contact,
these minute irregularities interlock, retard the motion, and
tear off the projecting particles.
What is the duty of a lubricant?
Ans. Its duty is to reduce friction.
SHAFT

TU
an
RUNI·
POLISHED SURFACE
AS IT APPEARS
UNDER MICROSCOPE
GRANULAR
Fig. 1.-Magnified view of a shaft showing its rough granular structure. In
operation, these minute irregularities interlock and act as a retarding force,
or frictional resistance, Hence, the necessity for lubrication which prevents
actual contact by presenting a thin intervening film against which the surfaces
rub. The magnifying glass shown above is simply suggestive of magnification,
in fact, to see the rough granular structure the shaft would have to be viewed
under a microscope.
How does a lubricant accomplish this?
Ans. By keeping the parts separate, being pressed out into
a thin film on which the moving parts rub thus preventing direct
contact.
Lubricants
1423
What term is applied to the tearing off of small metal
particles?
Ans. Wear.
What is the final effect of cutting?
Ans. If not remedied in time, it will result in freezing, that
is, the adhesion of the surfaces to each other.
Desirable Quality of a Lubricant.—There are several im-
portant requirements a lubricant should possess.
Name the several important requirements a lubricant
should possess.
Ans. 1, Body; 2, fluidity or viscosity; 3, freedom from gum-
ming; 4, absence of acidity; 5, stability under temperature
changes; 6, freedom from foreign matter.
Define body.
Ans. The body of a lubricant indicates a certain consistency
of substance, that prevents it being entirely squeezed out from
the rubbing surfaces.
What is fluidity of a lubricant?
Ans. This term refers to a certain lack of cohesion between
its different particles, which reduces the fluid friction.
What happens when a lubricant gums?
Ans. It loses its fluidity.
How about a lubricant that holds free acid?
Ans. The acid attacks the bearing surface, destroys its
⚫smoothness and as a result increases friction.
1424
Lubricants
How about stability under temperature changes?
Ans. Important.
Lubricants should retain their good qualities, even when used under
high temperatures as in a steam cylinder, or when used under low
temperatures, as in ice machines, or on exposed bearings. They should
not evaporate, not be decomposed by heat, nor congeal by cold and
should retain their normal body and fluidity as much as possible.
Cold, Flash, and Burning Points.-These are three critical
temperatures of a lubricant which limit its application and
which partly determine the conditions to which it is best suited.
Define cold point.
Ans. The temperature at which any given grade of oil will
freeze or become cloudy.
Define flash point.
Ans. The temperature at which the oil gives off inflammable
vapors.
What is the burning point?
Ans. The temperature at which oil takes fire.
Classes of Lubricants.-According to form or state, lubri-
cants may be classified as:
1. Solid;
2. Liquid;
and with respect to the composition as:
1. Animal;
2. Vegetable;
3. Mineral.
Lubricants
1425
S
What are the solid lubricants?
Ans. Graphite, soapstone and the various lubricating greases.
Graphite exists in two forms: Crystalline (or flake) and amorphous.
It is also known as black lead and plumbago. Black lead usually
refers to inferior grades of graphite, plumbago, to the Ceylon product,
and graphite, to the American product. Graphite may be used alone
or in combination with oil. The action of graphite is to fill the pores
of the metal making the rough surfaces smooth, rather than to form an
intervening film to prevent contact. Strictly speaking, graphite is not
a lubricant, but in filling the pores of the metal it greatly reduces
friction. One desirable quality of graphite when used in the cylinder
is that its presence in a boiler does not produce any injurious effect.
Soapstone, also called talc or steatite is used as a lubricant in the
form of a powder, or mixed with oil or fat. Mixed with soap, it is used
on surfaces of wood working against either iron or wood.
The various lubricating greases are well adapted for heavy
pressures under slow speed, but not for high speed, as their internal or
fluid friction is considerable. The lubricating quality of grease may be
improved by mixing with graphite. An advantage of grease is that it
does not run, hence the machinery can more easily be kept in a clean
condition.
What are the applications of liquid lubricants?
Ans. Liquid lubricants are used extensively for both internal
and external lubrications.
What animal oils are used?
Ans. Animal oils such as sperm, whale, fish, lard and Neat's
foot oils are used to some extent.
How are they obtained?
Ans. By boiling or melting from the raw animal parts. As
acid is sometimes used in the process of manufacture, animal
oils are liable to have an acid reaction, and are then undesirable.
Sperm oil is an excellent lubricant; it does not become rancid, nor
dry up; has good body and is fluid with little internal friction. It is used
1426
Lubricants
for rapid running parts, where a high grade is desirable, without much
regard to price.
Whale oil is frequently used for external lubrication; it is a good
lubricant at a moderate price.
Fish oil is also employed to advantage by some engineers for ex-
ternal lubrication.
Lard oil is used chiefly for mixing with other oils.
Neat's foot oil, on account of high price, is used in small quantities
only for improvement of oils of poorer quality.
How are vegetable oils obtained?
Ans. By pressing the raw materials, and cleansing out the
cloudy suspended fibres by treatment with acids. The color of
the refined oils is from water white to light yellow.
Under heat, vegetable oils evaporate easily, and are therefore, em-
ployed only for external lubrication. Vegetable oils are gradually de-
composed by the oxidizing influence of the atmosphere, and dry up;
they are also inclined to gum. Olive, cotton seed, peanut, castor, and
rape oil are all used to some extent.
Olive oil is a good lubricant; it neither dries up, nor gums, but
generally contains acid. On account of its high cost it is frequently
adulterated with cheaper oils.
Cotton seed oil dries up less easily than others, and is consequently
used sometimes as an admixture to olive oil. Certain grades frequently
show an acid reaction, and are undesirable for lubricating purposes.
Linseed oil dries up easily, and is therefore undesirable for lubrica-
tion; it is often found as an adulterant in other oils on account of its
cheapness..
How are mineral oils obtained?
Ans. By the distillation of petroleum.
These oils are the most important lubricants, and since, with modern
methods of manufacture, their price is relatively low. They retain their
qualities well in the air, and if pure, do not gum or dry up.
Describe a test for clearness.
Ans. A sample of the oil is taken from a barrel that has been
well rolled and shaken. The glass containing the sample should
Lubricants
1427
be transparent, and the oil, if very cold, should be warmed. The
oil then, if of good quality, will be clear. The amount of sus-
pended matter is, with a light oil determined by mixing and
shaking with a relatively larger quantity of gasoline.
How is the purity of an oil indicated?
Ans. By shaking a small quantity in a bottle with a quick
jerking motion, so as to produce air bubbles. If the oil be pure,
the bubbles will soon burst and disappear, but if mixed with
other oils, they will rise to the surface and collect.
How may animal matter be detected in oil?
Ans. About one oz. of the oil is placed in a 4 oz. bottle, and
two teaspoonfuls of powdered borax. If, on shaking, a soapy
deposit should form, the oil contains animal matter.
Describe the acid test.
Ans. A small quantity of oil is mixed with warm water or
alcohol, and tested with blue litmus paper, which will turn red
if any free acid be present.
S.A.E. Viscosity Numbers.-These numbers constitute a
classification of lubricants in terms of viscosity or fluidity, but
without reference to any other characteristics or properties.
The refiner or marketer supplying the oil is responsible for
the quality of its product. Their reputation is the car owner's
best indication of quality.
The S.A.E. viscosity numbers have been adopted by practically all
oil companies and no difficulty should be experienced in obtaining the
proper grade of lubricant to meet seasonable requirements.
Choice of a Lubricant.—There are several conditions that
determine the choice of a lubricant for any given purpose, and
the principal things to be considered are:
1428
Lubricants
1. Rubbing pressure
2. Rubbing velocity
3. Temperature
What is the requirement of a lubricant with respect to
pressure?
Ans. For heavy pressure it should have a good deal of body;
for lighter pressures there should be less body.
What is the requirement with respect to speed?
Ans. For high speed, a lubricant should, preferably, possess
good fluidity, while for slow speed, less fluidity is desirable.
Points of Lubricant Selection.-
1. The heavier and nearer constant the load, the greater the amount
of fuel burned, and consequently, the higher the engine temperature.
2. Automobile service seldom requires more than a small fraction of
the engine power and involves frequent slow down or idling periods.
The results are low operating temperatures.
3. If the conditions be such that high temperatures are to be ex-
pected, a heavy bodied rich lubricant, refined to meet severe heat
conditions would be desirable.
4. If the operating temperatures be moderate, oils of greater fluidity
will provide entirely adequate lubrication, and in fact, may be abso-
lutely necessary to meet other conditions.
5. During warm weather engine oil can be selected upon the basis
of the type of driving.
During cold weather, engine oil selection should be based
primarily upon easy starting characteristics, which depend
upon the viscosity (fluidity) of the oil at low temperatures.
Fig. 2 indicates the temperature ranges within which each grade can
be relied upon to provide easy starting and satisfactory lubrication.
Only 20 W, and 10 W, oils are suitable for use when weather condi-
tions are below 30° F. The reason for this is that the viscosity limits of
20 W, and 10 W, are taken at a temperature of 0° F., whereas those of
$
Lubricants
1429
S.A.E. 20, 30 and 40, all of which are summer grade oils, are taken at
a temperature of 130° F.
Crank Case Dilution.-By definition, this term means a
thinning of the crank case oil on account of certain portions of
the gasoline or fuel leaking by the pistons and rings and mixing
with the oil.

S.A.E-30
20-W
10-W+
10% KEROSENE
110
100
90
80
70
60
50
40
30
20
10
O
- 10
-20
-30
S.A.E-40
S.A.E-20
10-W
Fig. 2.—Temperature range for various oils S.A.E. numbers. Winter oils should
be selected on the basis of lowest temperature expected.
Leakage of fuel, or fuel vapors into the oil reservoir mostly occurs
during the warming up period when the fuel is not thoroughly vaporized
and burned.
Lubrication. The subject of lubrication should receive the
special attention and study of every engineer. It is quite
1430
Lubricants
1
important that the engine be properly oiled to avoid exces-
sive friction, wear, and trouble..
Owing to its importance the subject is treated at length in
the next chapter.
#
•
Lubrication
1431
CHAPTER 65
Lubrication
How to Oil an Engine.-The subject of lubrication should
receive the special attention and study of every engineer. It
is quite important that the engine be properly oiled to avoid
excessive friction, wear, and trouble. A small amount of a well
selected oil properly applied will go further in reducing friction
than a much greater amount of an unsuitable lubricant im-
properly applied.
Oiling an engine involves:
1. Internal lubrication; and
2. External lubrication.
1. Gravity;
2. Hydrokinetic;
a. Up flow;
b. Down flow.
3. Force feed.
The former includes oiling the cylinder and valves, and the
latter, the external bearings.
Internal Lubrication.-There are several kinds of lubri-
cator for introducing oil into the cylinder; these may be classi-
fied with respect to their principles of operation as:
1432
Lubrication
Gravity Lubricators.-Those working on this principle are
called "plain lubricators," there are two types, the invisible
feed, and the sight feed. The action of gravity lubricators
depends on: 1, the displacement of the oil from the reservoir
by condensation, and 2, its movement downward by gravity.
Fig. 1 is a sectional view of a plain lubricator with invisible feed.
In operation, steam passes through the central tube to the upper
part of the oil reservoir, where it condenses. The water thus formed
FILLING PLUG

DRAIN
OIL RESERVOIR
Har
STEAM
VALVE
OUTLET
Fig. 1.-Plain cylinder lubricator. In operation, steam passes and condenses
in the oil reservoir, displacing the oil which flows over the top of the tube and
down to the cylinder.
being heavier than the oil, sinks to the bottom, displacing a correspond-
ing amount of the oil.
Hydrokinetic Lubricators.*-The operation of lubricators
of this class depends on two well known principles of physics:
*NOTE.-The word hydrokinetic is defined as: "Relating, or pertaining to the
motions of fluids." It is applied to this class of lubricator, whose operation is due,
primarily, to the downward motion of an elevated body of water which displaces
the oil from the reservoir.
Lubrication
1433
1. If a body (the oil) be acted upon by two unequal pressures
it will move in the direction of the greater force.
2. The specific gravity, or the weight of a certain quantity
of oil is less than the same quantity of water, hence the oil
will rise to the top.
WELL
With these facts in mind, the operation of any hydrostatic lubricator
may be easily understood. There are two forms of hydrokinetic lubri-
cator as shown in figs. 5 and 6, and known as the up flow and down
B
B-

D.
POWELL
D
ZLAL SETTERS
S
ENSIGN
ROWELL
H
F
G
D
Figs. 2 to 4.-Plain cylinder lubricators. Fig. 2, plain lubricator without drain;
the valve in the shank makes it possible to fill the cup while the engine is
running and also acts as a feed regulator; fig. 3, plain lubricator with condens-
ing tube, oil regulating valve and drain valve; fig. 4, sight feed lubricator
with single connection. A, reservoir; B, filler; D, steam valve; F, drain; G,
feed; H, drain; S, sight feed glass.
flow types. In the former, the oil is visible, rising drop by drop in the
sight glass, while in the latter drops of water are seen descending to
the bottom of the oil reservoir.
The principal parts of an up flow lubricator as shown in fig.
5, are: 1, condenser; 2, oil reservoir; 3, tube connecting the
1434
Lubrication
į
condenser to the lower part of the reservoir; 4, tube connecting
upper part of the reservoir to, 5, the sight feed.
Steam from the main steam pipe passes into the connecting pipe
above the lubricator, and condenser, filling the condenser and part of
the pipe above it with water to some height as H. When the steam
valve is opened, the sight feed glass is also filled with condensation.
PLUG
710
WATER
TELET LETTERERE
-40000'
UP FLOW TYPE
H
CONDENSER
WATER
Tienes Bera
STEAM
FEED
WATER
DOWN FLOW TYPE

AJUBOKOP
000000
CONDENSER
她​日 ​PLUG
DRAIN
OIL
STEAM
WATER
DRAIN
FEED
Figs. 5 and 6.-Up flow and down flow hydrokinetic lubricators. In the up
flow type, fig. 5, the oil ascends, drop by drop, through the sight glass while
in the down flow type, fig. 6, descending drops of water are visible through
the glass sight discs. The operation of hydrokinetic lubricators depends on:
1, an excess pressure produced by a head of water, and 2, a difference in
density between the water and the lubricant.
How does this up flow lubricator work?
Ans. In operation (fig. 5), when the condenser and steam
valves are open, water from the condenser will pass down the
central tube to the lower part of the reservoir, and being heavier
Lubrication
1435

Key
N
F
8
LF 109-
LF 2
LF 104
LF 107
LF 20-
8
7+
LF 110
A 118

LF 21
FILL
spencatan shapita 15 THE CONTROLda,
LF 16
-158
·5001
Fig. 7.-"Crescent" sight up flow double connection lubricator. How to attach:
Attach to vertical steam pipe above the throttle by union coupling shank R,
and 3 feet of condenser pipe with the coupling H. How to use: 1, Close all
valves of lubricator and fill chamber through filling hole B, with clean oil
and replace cap; 2. Open wide steam valve D, and water valve N, and wait
until sight glass J, fills full of water before starting the cup. 3. Regulate oil
drops by valve C, at bottom of sight chamber to desired rate of feed. To pre-
vent pulsation, close valve N, more or less, as required. To replace sight
glass, if broken, remove cap K, and insert glass, leaving a little end play to
allow for expansion. To refill, draw off water through drain valve F, and
proceed as before. Clean sight glass by blowing steam through vent cock V.
To prevent freezing, be sure to drain the lubricator. Draw off any unused
oil and condensed water by opening valves N and F, drain plug V, and
filling cap B.
Fig. 8.-Down flow sight feed lubricator. The parts are: 5,001, glass; LF2,
support arm; LF21, condenser; LF104, oil tube; LF4, feed valve pkg. rings,
not shown; LF107, oil feed valve stem complete; LF116, water feed valve
stem complete; 11, packing nuts; 158, filler plug; LF110, tail pipe (single
connection only); A118, tail nut; 8, drain valve body; 8, drain valve stem;
oil tube ball check; 23, plug for tube hole, in double connection, not shown;
LF105, tail pipe for double connection, not shown; LF 109, equalizing tube
(single connection only); water feed ball check; LF20, body for ¼ pint;
LF22, body for 3 pint; LF23, body for ½ pint; LF24, body for 1 pint;
LF25, body for 1 quart.
1436
Lubrication
than the oil, will stay at the bottom, the oil floatng above. On
account of the excess pressure in the condenser tube due to the
head H, the water will continue to flow until the oil fills the
upper part of the reservoir. When the feed valve is opened, the
excess pressure due to the head of water will force the oil, drop
by drop, through the nozzle in the sight glass. As soon as a drop
of oil leaves the nozzle, it is no longer acted upon by this excess
pressure, but rises because it is lighter than the surrounding
water in the sight glass.
Describe the down flow lubricator.
Ans. In this type (fig. 6) there are no internal pipes connect-
ing with the condenser and sight feed. The sight glass consists
of two glass discs inserted in the upper part of the reservoir as
shown.
How does the down flow lubricator work?
Ans. The operation is quite simple: When the condenser
needle valve is opened, the water from the condenser will flow
through the passage, and, as can be seen through the sight
discs, leave the nozzle drop by drop. It being heavier than the
oil, descends to the bottom, displacing an equal amount of oil
which is discharged into the main steam pipe.
Practical Points.-Engineers experience more or less trouble
in the daily operation of lubricators from one cause or another.
To avoid this, the foregoing principles should be clearly under-
stood.
What should be done before starting a lubricator?
Ans. Time should be allowed for the condenser and sight feed
glass to fill.
Lubrication
1437
Mention a common fault.
Ans. Fouling of the sight glass.
What causes this fouling?
Ans. It is usually due to the condition of the nozzle.
PLUG
The nozzle frequently becomes covered with dirt and sediment from
the oil, which makes the surface rough, causing the drops to adhere
too long to the nozzle. This condition causes the drop to become so
large that it strikes the side of the glass in rising, thus gradually covering

SHANK
Mi
CAP
A
#HITTARCIIH).
הו
OIL RESERVOIR
STRAINER
SUCTION VALVE
DISCHARGE VALVE
A
OUTLET
Fig. 9.-Hand oil pump; for occasional use in cylinder lubrication. It may be
attached either vertically or horizontally by interchanging the shank and
plug. A valve should be placed on the outlet, and shouod be kept closed
when the pump is not in use.
the glass with particles of oil which become detached from the drop at
each contact. This may be overcome by removing the glass and cleaning
the nozzle both inside and out, rubbing it smooth with crocus cloth.
Why does the nozzle sometimes become covered with
dirt and sediment from the oil?
1438
Lubrication
Ans. Sometimes the orifice in the nozzle is large for the kind
of oil used. This causes large drops to form, which tend to foul
the glass.
What periodic attention should be given to a lubricator?
Ans. It should be blown out occasionally so as to remove
any dirt or sediment that may have accumulated in the small
tubes and passages.
POWER LEVER

FEED
ADJUSTMENT
the
PLUNGER
PLUNGER
111111
LMI
SIGHT FEED
METROV
OUTLET
Fig. 10.-Power sight feed oil pump. The oil is forced out of the reservoir and
through the sight glass by the upper plunger, and is then forced on through
the check valves and into the cylinder by the lower plunger. The amount of
oil supplied with each stroke is regulated by the adjustable upper plunger.
What attention should be given to the lubricator when
the engine is shut down as during the noon hour and
why?
Ans. Close the feed valve, but condenser valve in the up
flow type should be left open. If both valves are shut there
will be no outlet, hence, if the temperature of the oil should
rise, it will expand and exert such a pressure on the reservoir a
to cause it to bulge or burst.
Lubrication
1439
:
Force Feed: Oil Pumps.-Hydrokinetic lubricators are
affected by changes in temperature, causing them to feed too
slow in cold weather and too fast in warm weather. In an effort
to overcome this defect, what is known as force feed, or oil
pump lubricators have been designed and put on the market
VACUUM CHECK VALVE

®
®
UC
FW
TOY!
Fig. 11. Method of attaching a power oil pump to cylinder. A vacuum check
valve is placed at the end of delivery pipe to prevent the oil being siphoned
out of the reservoir in case a vacuum form in the boiler or cooling. Motion
for operating the plungers is obtained from some convenient part of the
valve gear.
with more or less claims as to their ability to provide positive
and uniform lubrication.
Name two kinds of force feed lubricator.
Ans. 1. The hand pump which is used as an auxiliary to the
main lubricator, and 2, the power pump operated by the engine,
and employed as the regular feed.
1440
Lubrication
Describe the ordinary hand oil pump.
Ans. As shown in fig. 9, the oil reservoir has a removable
strainer inserted in the central tube, and the filling hole is
covered by a cap to keep out dust and impurities. The pump
is of the single acting plunger type with ball valves as shown.
By reversing the positions of the plug and shank, the lubricator
may be adapted to horizontal connection.
How does the power force feed pump shown in fig. 10
work?
Ans. In operation, oil is drawn from the reservoir and forced
through the sight glass by the upper plunger; it is then forced
on through the check valves and outlet by the lower plunger.
The amount of oil supplied with each stroke is regulated by the
adjustable upper plunger. The lower plunger is made slightly
larger than the upper, to avoid any possibility of oil remaining
in the sight glass. Motion is imparted to the plungers by
means of a ratchet wheel and cam, which in turn are moved
by a lever connected to some reciprocating part of the engine.
There is a hand attachment on the ratchet wheel to permit
hand operation before starting the engine, or when more oil is
needed momentarily while the engine is running.
External Lubrication Systems.-The successful lubrica-
tion of the bearings of an engine depend in a measure upon
the character of the appliances used to convey the lubricant
to the wearing surfaces. There are several systems of external
lubrication, the choice of which is governed by the type of
engine, and conditions of service.
They may be classified as:
1. Gravity;
2. Inertia;
3. Centrifugal;
!
Lubrication
1441
4. Capillary
5. Pressure;
6. Compression;
7. Splash.
PILGRIM
muted dialin
Besturi
LIVE
POWELL
wick feed;
chain, and collar feed;

R
O
S
R-
C
Lob
SIGNAL
POWELL
с


LUNKENHEIMER CINC.
Fig. 12.-Pilgrim plain glass oil cup. The feed is regulated by the milled screw
feed stem R, and is secured by the winged jamb nut O.
Fig. 13.-Signal snap lever sight feed oil cup. The feed is turned on or off by
the snap lever C, being on in the vertical position and off in the horizontal
position. The rate of feed is regulated by the milled screw feed stem R, and
secured by the wing nut O.
Fig. 14.-Crown index sight feed oil cup. The index device is for regulating the
feed, and the indicator arm turning on the lid, marks the notch giving the
desired feed.
1442
Lubrication
Gravity Systems.
In this method of oiling, the lubricator
is placed at a sufficiently high elevation to permit the oil to
gravitate or flow to the bearing. Many of the sight feed cups
work on this principle.
These cups are made in single or multiple units as shown in
figs. 12 to 14. The working of these cups is described under the
cuts.
Capillary Systems. These include wick feed lubricators,
and the chain, and collar devices used in self oiling bearings.
FLUSH
ME
';{\
OFF
FEED
T
LUNKENHEIMER
CINCINNAT
OFF

Fig. 15. Multiple sight feed oiler. This consists of a number of sight feeds of
the "Sentinel" type placed in a common reservoir. A union is placed at the
end of each feed for easy connection with the oil pipes. Each end of the
cylindrical reservoir is closed with a glass disc making the supply of oil visible.
Describe the wick feed lubricators.
Ans. Wick feed lubricators are provided with one or more
small tubes, tapped oil tight, into the bottom of the reservoir,
and reaching to the top as shown in fig. 25.
How does the wick feed lubricator work?
Lubrication
1443
ANCHOR
Ans. To lift the oil automatically over the top of the tube a
wick is inserted with one end dipping into the oil in the reservoir.
The end of the tube and wick must project below the bottom
of the reservoir. A wire is attached to the wick to hold it in

WIPER
Fig. 16.-Oil cup with two branches for lubricating wrist pin and guide. A
wiper cup is placed on the cross head, and an angle sight feed on the guide.
place. The wick, due to capillary attraction, becomes saturated
with oil, which is siphoned from the reservoir drop by drop.
What may be said of wick feed lubricators?
Ans. The system is used extensively on marine engines, and
1444
Lubrication
although very reliable, the rate of feed cannot be regulated so
easily as the gravity feed.
Describe the endless chain oiler.
Ans. An endless chain or collar is used on what is known as
a "self oiling" bearing, as shown in figs. 26 and 27. The length

B
A
E
********
區
​LAT
Fi
11:
‹ ¡
F
B
G
с
**** ***
D
Fig. 17 to 24.-Various oiling devices. A, is an oil regulating valve with
sight feed; B, angle oil regulating valve with sight feed; C, wiper cup; D,
angle wiper cup; E, wiper; F, angle wiper; G, wiper; H, drip cup.
of the chain is such that it dips into an oil reservoir directly
under the bearing and in rotating with the shaft, the ascending
side carries with it, by attraction between the liquid and metal,
a small quantity of oil which lubricates the shaft.
Inertia System.-Lubricators which operate on the force
due to inertia are adapted to oilng a reciprocating part moving
Lubrication
1445
**
GAUGE
WIRE HOLDER

RESERVOIR
TT
TTTTT
BOURAG
Buty
CHAIN
SHAFT
WICK
10
CRET
QA
OIL PIPES TO BEARINGS
Fig. 25.-Multiple wick feed oil cup. A number of tubes are tapped oil tight
through the bottom of the reservoir; these extend above the oil level, and
have a wick inserted in each with one end dipping in the oil. It soon becomes
saturated by capillary action and is then siphoned drop by drop. A wire is
attached to each wick so that they may be easily inserted or removed from
the tube.
AUXILIARY FEED
RESERVOIR.
INKRONI

51
32
Figs. 26 and 27.—Sectional views of chain oiling bearing of a typical engine.
An endless chain encircles the shaft and dips into the oil reservoir beneath.
As the chain moves with the shaft, oil clings to the ascending side, and is thus
carried to the top of the shaft for lubrication; any excess drains back to the
reservoir through the passages in the lower portion of the bearing.
1446
Lubrication
in an up and down direction, as the wrist pin of a vertical en-
gine. Two types of inertia cups are shown in figs. 28 and 29.
How does the type shown in fig. 28 work?
Ans. The central tube connecting with the outlet contains a
plunger feed valve, which by its inertia opens or closes at each
end of the engine stroke, thus acting as a piston in forcing the
oil to the bearing at each revolution. The amount of opening
R
MINDRU
PLANET
POWELL
tempenhoutANIA
R
- O


WARIS
POWEL
O
Fig. 28.-Planet plunger feed crank pin oil cup. The plunger feed valve acts as
a piston, forcing the oil to the bearing at each revolution.
Fig. 29.-Polaris crank pin oil cup with needle point feed. This type of feed
permits nicety of adjustment, at the same time insuring a positive feed for
crank or wrist pins.
or stroke of the plunger valve is adjusted by the milled nut R,
and set by the jamb nut O.
How does the type shown in fig. 29 work?
Ans. In this oil cup valve is made stationary and the feed
obtained by the inertia of the oil itself.
Lubrication
1447
In this cup the oil is thrown against the top at the beginning
of the down stroke and enters the central tube. The rate of
feed is adjusted by the valve R.
GRAVITY FLOW.

Fig. 30.-End view of crank case showing detail of crank disc "pump" lubri-
cating system for a compressor. Oil is carried on the outer rim of each crank
disc to the top where it is diverted into an oil boat by an oil wiper mounted
on a stud in the oil boat. The "oil boat," which is bolted to the main bearing
cap, has four compartments. All of the oil is poured into one main compart-
ment from which it overflows to each of three supply compartments. From one
supply compartment the oil is carried through a cored opening in the oil boat,
to the main bearing. One supply compartment is piped to a sight feed oiler
at the cross head guide which lubricates the cross head guides and the cross.
head pin bearing. The other supply compartment is piped to a centrifugal oiler
which carries oil to the crank pin bearing. The particular feature of this system
is that the only running part that dips into the oil surface is the smooth rim at
the circumference of the crank disc which acts as a pump in carrying oil up to
the oil boat from which it is distributed to the bearings by gravity flow. The
system is reliable and splashing and agitation of the oil are reduced to a
minimum if the correct oil level be maintained. The oil boat, oil wiper and all
piping are free from the crank case oil guard and may be adjusted with the
guard removed. For inspection of the lubrication system while the machine is
running, hand hole covers are provided at the main bearings, at the top of
the crank disc, and in the cover at the cross head.
1448
Lubrication
Centrifugal System.-For oiling crank pins, lubricators
are sometimes used which depend on centrifugal force for
their operation. A typical construction is shown in figs. 31
and 32.
Describe this oiler.
Ans. In figs. 31 and 32 a grooved ring is attached to the
crank to the oil from the sight feed. There is a connecting


OIL PASSAGE
RING
Ø
FEED
GROOVE
CENTRIFUGAL FORCE ACTING ON OIL
Figs. 31 and 32.-Ring centrifugal crank pin oiler. This type is adapted to
center crank engines. An oil passage leads from the grooved ring to the crank
pin. In operation, the oil, which drops into the groove, is carried off by cen-
trifugal force through the oil passage to the crank pin. In construction, the
oil passage should be of liberal size to prevent clogging.
passage or duct through which the oil may flow from the
groove to the crank pin bearing.
How does it work?
Ans. In operation, centrifugal force tends to throw the oil
Lubrication
1449
1
from the center of rotation, hence it presses against the bottom
of the groove and is forced through the duct to the bearing,
thus lubricating the pin. This type of oiler is used mostly on
center crank engines.
What kind of oiler is used for a side crank engine?
Ans. The pendulum bob type.

:n
C
E-
E
T
ARTD
KH
D
CA
K
+3
Ex
H-
POWELL
JA
C
b
a
Figs. 33 and 34.-Individual sight feed lubricating device. Fig. 33, standard
pattern; fig. 34, enlarged pattern. It is intended for use when it is desired to
lubricate the cylinders of two or more engines from one large capacity pressure
tank conveniently located. The supply being taken from the top of the tank,
and by means of 1/4 inch pipe conducted to the device and connected at
coupling H. The attaching shank R (% pipe) is screwed into the steam pipe.
C, is drop regulating valve, V, blow off valve for cleaning sight chamber. K,
is removable plug through which the sight glass is replaced. For compound
engines it is best to use an equalizing pipe connected to steam pipe above
the throttle. When so used, bonnet T, is replaced with a union coupling. Using
this device saves the time ordinarily required in filling the sight feed lubricators
on each engine.
1450
Lubrication
:
Describe the pendulum bob oiler.
Ans. The tube or arm through which the oil flows by cen-
trifugal force to the crank pin is bolted to the end of the crank
pin, the bearing at the other end which carries the cup is con-
centric with the center of the shaft, thus the oil cup, which is
here journaled, and weighted with a pendulum bob, remains
stationary, and in an upright position.
2
[***
PENGUIN
POWELL
R
0

Fig. 35.-"Penguin" slide sight feed oil cup designed for use on slides, cross
heads, eccentrics, and all moving bearings. The feed is easily set up regulating
feed stem R, and secured by jamb nut Ö. The filling plug is attached to cup
by a small chain to prevent its getting lost.
How does it work?
Ans. In operation, the oil drops from the end of the inner
tube, and is carried by centrifugal force to the crank pin.
The cup is circular in section and has glass sides to indicate the
amount of oil. The feeding arrangement consists of a tube screwed into
the base and communicating with the outlet. At the top is a regulating
valve. The cup is placed in an upright position at the end of the con-
necting rod. In operation the centrifugal force due to the rotary move-
ment of the cup, throws the oil outward against the circular walls and
Lubrication
1451
LIEBERS
the feed inlet. It is obvious, no matter how little oil there may be in
the cup, it will be carried to the feed inlet.


Figs. 36 and 37. — Side and front views of crank pin oiler. The tube or arm
through which the oil flows by centrifugal force to the crank pin is bolted solid
to the end of the crank pin and is half the stroke of the engine in length, so
that one end is always concentric with the axis of rotation. On this latter end
is journaled an oil cup holder weighted with a pendulum bob which keeps
the oil cup stationary and in an upright position. The cup holder is held in
place by a cotter pin extending into a groove cut into the journal. The arm
consists of the tube, bowl, journal and end, which bolts to the crank pin.
The bolt is drilled, as shown, connecting the oil conduit in the arm to thar
drilled in the crank pin.
Pressure Systems.-The necessary pressure for forcing the
lubricant to the bearings may be obtained 1, by placing the
reservoir at a suitable elevation; 2, by employing air pressure
in a closed reservoir, or, 3, by means of a force pump.
An example of a pressure system is shown in figs. 38 and 39.
1452
Lubrication
Compression System: Grease Cups.-Grease is frequently
used instead of oil on some bearings, especially those which run
slowly and with considerable pressure. The numerous kinds of
cup used for the application of grease may be classed as:
1. Hand operated;
2. Automatic.
All grease cups operate by compression.
Three simple types are shown in figs. 40 to 42.

ENCLOSED
CRANKCASE
E
OIL
PRESSURE
GAUGE
PUMP
RELIEF
VALVE
STRAINER
Figs. 38 and 39.-Views of a vertical engine showing pressure system of
lubrication. The frame is enclosed, and at the bottom is an oil reservoir and
pump which is operated by the engine. This pump forces the oil through a
system of pipes to all the bearings from which it drains back to the reservoir.
How does the plain cup shown in fig. 40 work?
Ans. By screwing down the cap over the stationary bottom
part grease is forced through the outlet to bearing.
What is the application of the "marine type" shown in
fig. 41?
Lubrication
1453
Ans. It is a desirable cup in places where it is necessary to
force the grease some distance to the part to be lubricated.
How does the marine cup work?
Ans. By turning the handle attached to the piston the grease
is compressed and forced out of the cup.
Describe the automatic cup shown in fig. 42.
:
A~
POWELL
с
B
-K
C.
•

Bin

KOOIE
H
WINTE

BAUDUMAUREE
A
B
Figs. 40 to 42.-Hand and automatic compression grease cups. Fig. 40 shows
a simple cup, and fig. 41, a "marine type" with screw piston. The automatic
cup shown in fig. 42 is provided with a leather piston which may be raised
by means of the thumb nut B, for refilling. The thumb nut, which controls the
spring and piston, has a locking arrangement which retains it in position, on
the stem C. The feed is regulated by means of the screw plug valve A. J, handle;
K, screw piston.
Ans. It is provided with a leather piston which is easily
raised by a thumb nut, whenever re-filling is necessary. The
thumb nut which controls the spring and piston, has a locking
arrangement, which prevents it jarring from its position on the
main stem.
1454
Lubrication
How do you fill the cup?
Ans. To fill the cup, thumb nut B, is turned to the right
which draws the piston to the top; the cup is then unscrewed
from the base and filled with grease. After replacing, pressure
is put upon the grease by screwing thumb nut B, to the top of
the stem C, thus allowing the piston to be pressed downward
by the spring.
How is the rate of feed regulated?

Fig. 43. Horizontal engine; sectional view showing splash system of lubrica-
tion. Oil is placed in the enclosed frame in sufficient quantity to submerge the
connecting rod at its lowest point of travel, causing it to splash the oil over
the various bearings. It should be noted that the piston rod stuffing box is
outside the enclosed portion of the frame thus keeping the oil separate from
any water of condensation, which may leak past stuffing box an important
point in this system.
Ans. By means of plug A, which is drilled to register with
the feed passage, according to the position of the plug.
If it be desired to stop lubrication while preserving the rate of feed,
thumb nut B, is turned down to the top of the cup, thus preventing the
further advance of the piston.
Lubrication
1455
SHAFT
Splash System.
With this method of lubrication an en-
closed frame is necessary. A quantity of oil is placed in the
frame and maintained at such a level that the end of the
connecting rod comes in contact with it at the lower part of
the revolution, thus splashing it upon the working parts. This
system is frequently used with high speed horizontal engines
as shown in fig. 43.

OIL
RINGS
RESERVOIR
Ma
DRAIN
COCK
I ig. 44.-Sectional view showing a ring oiler or self oiling bearing. As shown
the pedestal or bearing standard is cored out to form a reservoir for the oil.
The rings are in rolling contact with the shaft, and dip at their lower part into
the oil. In operation, oil is brought up by the rings which revolve because of
the frictional contacts with the shaft. The oil is in this way brought up to the
top of the bearing and distributed along the shaft gradually descending by
gravity to the reservoir, being thus used over and over. A drain cock is pro-
vided in the base so that the oil may be periodically removed from the reservoir
and strained to remove the accumulation of foreign matter. This should be
frequently done to minimize the wear of the bearing.
Upon what does the amount of oil splashed over depend?
Ans. It depends upon the rate of speed and the depth of
the oil in the frame. As with the pressure system the oil should
be frequently filtered and renewed.
1
1456
Lubrication
LUBRICATION CHART
for
HOISTING. AND HOISTING & CONVEYING APPARATUS
& CONVEYING APPARATUS
Lidgerwood equipment is usually subjected to severe service conditions, exposure to all kinds of
weather, suddenly applied loads and dust and dirt prevalent in outside work. Regular attention to
lubrication of the working parts is essential.
Long wearing smooth running machines depend on the care and attention of the operator or men
in charge. No points should be slighted or neglected and the time between applications should not
be extended so far that the surfaces run dry part of the time. Applying a larger quantity of the lu-
bricant does not compensate for longer intervals. The safe practice is to apply, frequently and in
small quantity.
In winter service particularly at temperatures below 32° F. the use of lighter more fluid oils and
greases insure better response to the controls, less power consumption and better film formation be-
tween the rubbing areas.
Gasoline and Diesel engine operation offers a favorable opportunity for lowering operating costs
by using good quality oil, keeping the crankcase filled and changing at intervals not longer than 100
hours operation.
BEARINGS:
Mechanical forced feeds
Ring oiling
Sight feed
Hand oiled by oil can
Pressure grease fittings
Turn down grease cups
Ball or roller bearings
GEARS OR DRIVE CHAINS:
Open gears
SAE 30 summér SAE 10 winter
or as determined by relative
temperature of exposure.
Navy Symbol equivalent 3065 or
1065 for SAE 30 and 2110 for
SAE 10.
Cup grease No. 2 or 3 summer, No. 1 or 2 winter.
Cup grease No. 3 summer, No. 2 winter.
Cup grease No. 2 or 3 summer, No. 1 or 2 winter.
SAE 90 summer, SAE 80 winter, Navy Symbol 3080 or 1080 cor-
responds to SAE 80 and Navy 3080, 3100 or 1100 to SAE 90. Oil
should be poured on hot, especially on helical or herringbone gears;
cold application is likely to cause "pounding" on latter.
Lubrication
1457
Enclosed gears, splash
Worm gearing
DRUM BUSHINGS:
Oil preferred
FRICTION SCREW OIL BOX:
Oil preferred
ELECTRIC MOTORS:
GASOLINE MOTORS:
Crankcase
Water pump
DIESEL MOTORS:
Crankcase and water pump
STEAM CYLINDERS:
AIR CYLINDERS:
SHEAVES
Waste packed oil chambers
Ball or roller bearings
WIRE ROPE AND CABLE:
SAE 90 summer, SAE 80 winter.
Follow manufacturer's directions; heavy oil SAE 90 or SAE 80
according to exposure generally used.
SAE 90 summer, SAE 80 winter; if too much leakage cup grease
No. 2 or 3 summer, No. 1 or 2 winter may be used.
SAE 90 summer or winter; if too much leakage cup grease No. 3
summer, No. 2 winter may be used,"
Follow directions of motor manufacturers, but generally oil and
grease as listed under "Bearings"; Navy Symbols for ring oiled
bearings, above 75 HP, 2135 or 2190, 3050 or 3065 (SAE 30)
below 75 HP, 2110 (SAE 10) 2135, 3050 (SAE 20).
SAE 30 summer, SAE 10 winter.
Cup grease No. 4 waterproof, Army letter WP.
Follow instructions of manufacturers or the same as for gasoline
motors with some exceptions for very special motors.
SAE 90 or 600 W or Navy Standard 6135, heavier than either pour
point being 60° F.
·
For the hoist cylinders which all use compressed air expansively, it
is necessary for determining proper lubricating oil to know pressure
and temperature of incoming air and temperature of exhaust - Navy
Symbols, heavy oil, 8190 or 2190, are given as general lubricant for;
air compressor cylinders where air is not used expansively.
SAE 90 summer or winter; heat or use pressure oil can.
Same as listed under "Bearings".
Follow instructions of manufacturers or, if lacking, use SAE 90 of
Navy Symbol 5190. For either rope or cable, should be applied
hot; heated oil may be poured on rope from a can with spout as
rope is being wound slowly on drum. For main cables a small
reservoir with drip cock may be mounted on cable carriage above
main cable and carriage moved slowly along cable with cock partly
open. A more thorough application which many riggers, prefer is
by hand of a man riding on carriage, thus smearing the complete
surface of cable, upper, lower and sides.
NOTE: The SAE numbers for oil and grease and Navy Symbols for oil conform to official requirements
of Army and Navy for corresponding elements of hoist, as well as ropes.
1458
Lubrication
:
Practical Points on Lubrication.
The engineer should
give special attention and study to the subject of lubrication,
not only to avoid waste, but as a safeguard against the possi-
bility of a shut down. An engine running up to speed no matter
whether it be slow, medium, or high speed, should have the
constant attention from the man in charge.
The temperature of the engine room has much to do with the rate of
feed of oil cups and cylinder lubricators; the higher the temperature
the faster will the oil flow.
Where two oil cups are used on a long bearing they should be placed
not further on each side of the center than 1% the length of the bearing.
Oil grooves, after being cut in a bearing should have the edges rounded
with a scraper to let the oil follow the shaft; sharp edges have a ten-
dency to scrape off the oil.
Oil should be applied to the shaft at some point outside the area upon
which the pressure comes. This can be done by the proper arrangement
of the oil grooves.
The amount of oil required for a bearing should be determined with
care by repeated trials; where there are no drip pans, it is important
that the bearing receive no more oil than necessary, to avoid waste
and to keep the engine room clean.

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A NEW MODERN, COMPREHENSIVE GUIDE ON PUMP, HYDRAULIC AND AIR PROBLEMS FOR
ENGINEERS, OPERATORS, MECHANICS, STUDENTS, WITH QUESTIONS AND ANSWERS.
1658 Pages-3 Books in one-fully illustrated.
Practical Information covering:
PUMPS SECTION A-908 PAGES: Centrifugal-Rotary--Reciprocating Pumps-their theory, con-
struction, operation and calculations. Air and Vacuum Chambers-Power Pumps-Air Pumps-Jet Con-
densers Surface Condensers-Condenser Auxiliaries-Condenser Operation-Calculations. Cooling Ponds
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Dredges-Code.
HYDRAULICS-SECTION B-320 PAGES: Hydraulic Physics-Drives-Machine Tool Power-Accumu-
lators-Elevators-Airplane Control-Automobile Brakes-Shock Absorbers-Presses-Turbines.
AIR COMPRESSION-SECTION C-406 PAGES: Compression-Work-Compressor Classification-
Parts, Types-Inter and After Coolers-Regulating Devices-Installation-Lubrication-Operation-
Maintenance-Blowers-Superchargers-Pneumatic Hand Tools.
A PRACTICAL TREATISE with a Ready Reference Index of 24 Pages.
AUDELS WELDERS GUIDE.
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A CONCISE, PRACTICAL TEXT ON OPERATION AND MAINTENANCE OF ALL WELDING
MACHINES, FOR ALL MECHANICS.
Over 400 pages, fully illustrated, 5 x 6½ x 2, flexible covers.
Covers Electric, Oxy-acetylene, Thermit, Unionmelt Welding for sheet metal, spot and pipe welds,
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and hard facing, cutting, brazing-eye protection. EVERY WELDER SHOULD OWN THIS GUIDE.
AUDELS ANSWERS ON BLUE PRINT READING.$2
COVERS ALL TYPES OF BLUE PRINT READING FOR MECHANICS AND BUILDERS.
376 pages, very fully illustrated, service bound, pocket size.
How to read scales-the standard symbols-detail and assembly prints-the different kinds of working
drawings: orthographic, pictorial, descriptive-development by parallel and radial lines, conventional
lines, triangulation. Warped and other surfaces-specifications-how to sketch-how to make working
drawings-how to make blue prints-short cuts-helps-hints and suggestions.
"The blue print of to-day is the machine of to-morrow." The man who can read blue prints is in line
for a better job. This book gives you this secret language, step by step in easy stages.
NO OTHER TRADE BOOK LIKE IT-NEW, COMPLETE.
□ AUDELS SHEET METAL WORKERS
HANDY BOOK..
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Containing practical inside information, essential and important facts and figures. Easy to understand.
Fundamentals of sheet metal layout work. Clearly written in everyday language covering: Aircraft sheet
metal work, principles of pattern cutting, sheet metal work layout, development of air conditioning
ducts, sheet metal machines, welding sheet metal, boiler plate work, practical drawing, how to read
plans. geometrical problems, mensuration. FULLY ILLUSTRATED. READY REFERENCE INDEX.
388 PAGES HANDY SIZE-FLEXIBLE BINDING
AUDELS SHEET METAL PATTERN LAYOUTS. $4
10 Sections, 1100 pages, 350 layouts, 1600 illustrations.
A PRACTICAL ILLUSTRATED ENCYCLOPEDIA COVERING ALL PHASES OF SHEET METAL WORK
INCLUDING PATTERN CUTTING, PATTERN DEVELOPMENT AND SHOP PROCEDURE.
10 Big Sections Covering: Heating & Air Conditioning Duct Patterns-Special Sheet Metal Layouts-
Layouts for various sheet metal shapes-Conductors, Leaders and Leader Head Layouts-Gutters and
Roof Outlet Layouts-Sheet Metal Roofing Patterns-Skylights and Louvers Pattern Layouts-Cornice
Pattern Layouts-Sheet Metal Boat Patterns-Geometrical Problems, Mensuration and Sheet Metal
Mathematics.
K
Developed by experts for Sheet Metal Workers-Layout men-Mechanics and Artisans, Apprentices and
Students. A MASTER BOOK FOR ALL THE SHEET METAL TRADES.
AUDELS AIRCRAFT WORKER.
$I
A HANDY POCKET BOOK FOR ALL MECHANICS, LEADMEN, LAYOUT MEN, DRAFTSMEN, DE-
SIGNERS. APPRENTICES AND STUDENTS. 240 pages-fully illustrated and indexed. Flexible binding.
Answers your daily questions with clear, concise practical information, pointers, facts and figures relat-
ing to current modern shop practice. The information, illustrations, charts, tables, etc., are compiled
from practical shop experience and procedure as practiced in leading Aircraft Plants and taught in official
apprentice and refresher Courses. Authentic, reliable, up-to-date.
Sections Covering: 1 Aircraft Materials, Terms, Parts-2 Blueprints, Working Drawings-3 Mathe-
matics. How to figure-4 Layout and Bending-5 Tools and Machines-6 Riveting, Spot Welding and
Hints-7 Fabrication, Blocking, Angles, etc.-8 Assembly, Fuselage, Wing & Final. How to Use Tools-
Tables & Data, Symbols, Army & Navy Specifications, etc.
EVERY AIRCRAFT WORKER SHOULD OWN THIS BOOK.
AUDELS MATHEMATICS & CALCULATIONS
FOR MECHANICS
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MATHEMATICS FOR HOME STUDY OR REFERENCE. 700 pages, 550 illustrations, pocket size.
This work has been arranged as a progressive study, starting with the first principles of arithmetic and
advancing step by step, through the various phases of mathematics, including the many necessary rules
and calculations, for figuring mechanical and electrical engineering problems. Thousands of mathematical
calculations and tables, fully indexed for quick use.
Practical mathematics from the beginning. How to figure correctly. New, easy, correct methods covering
a complete review of practical arithmetic. Illustrated with examples. Includes mensuration-plane and
solid geometry-trigonometry-algebra-calculus-electrical and mechanical shop calculation-practical
tests-reference tables and data. How to use the slide rule. A REAL HELP TO ALL MECHANICS.
AUDELS NEW MACHINISTS & TOOL MAKERS
HANDY BOOK.
$4
COVERS MODERN MACHINE SHOP PRACTICE IN ALL BRANCHES. 5 PRACTICAL BOOKS IN ONE.
New from cover to cover. Tells how to set up and operate lathes, screw and milling machines, shapers,
drill presses and all other machine tools.
1600 pages, fully illustrated, 5 x 62 x 2, flexible covers. Indexed. 5 sections, 60 chapters. Easy to
read and understand.
A complete instructor and reference book for every machinist, tool maker, engineer, machine operator,
mechanical draftsman, metal worker, mechanic and student, covering lathes, screw and milling machines,
shapers, drill presses, etc. 5 practical books in 1: Section 1: Modern machine shop practice-2: blue
print reading-3: mathematics for machinists-4: shop physics-5: how to use the slide rule.
A SHOP COMPANION THAT ANSWERS YOUR QUESTIONS.
AUDELS DIESEL ENGINE MANUAL.
$2
A PRACTICAL, CONCISE TREATISE WITH QUESTIONS AND ANSWERS ON THE THEORY, PRAC-
TICAL OPERATION AND MAINTENANCE OF MODERN DIESEL ENGINES.
384 pages, fully illustrated, flexible binding, pocket size.
Explains in simple, concise language Diesel operating principles-engine starting-air starting valves-
fuel spray valves-inlet and exhaust valves-valve timing-fuel pumps-fuel injection compressors-
starting air compressors-scavenging air compressors-pistons and piston rings-cylinders-lubrication
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high speed Diesel engines-answers on operation-horse power calculations, including two-cycle
Diesel engines. ALL DETAILS ARE PLAINLY BROUGHT OUT. THIS BOOK IS OF EXTREME VALUE
TO ENGINEERS, OPERATORS, STUDENTS.
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AUDELS MECHANICAL DICTIONARY
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A WORD BOOK FOR MECANICS. COVERING THE MECHANIC ARTS, TRADES AND SCIENCES.
950 pages, 534 x 8 x 134, flexible binding.
A very useful book. If constantly referred to will enable the student to acquire a correct knowledge of
the words, terms and phrases in use in mechanical engineering and its various branches. Included are
valuable tables, formulas and helps-an encyclopedia as well as a dictionary.
□AUDELS NEW AUTOMOBILE GUIDE
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A PRACTICAL READY REFERENCE FOR AUTO MECHANICS, SERVICE MEN, TRAINEES & OWNERS
Explains theory, construction and servicing of modern motor cars, trucks, buses, and auto type
Diesel engines. 1540 pages, fully illustrated, 5 × 6½ x 2. 55 chapters. Indexed.
FEATURES: All the parts of an automobile-automotive physics-the gas engine-pistons-piston
rings-connecting rods-crank shafts-the valves-the valve gear-cams and cam action-valve timing
-cooling systems-gasoline-fuel feed systems-the mixture-carburetors-automatic choke-super-
chargers transmissions-synchro-mesh-clutches-universals and propeller shafts-the differential-
rear axles-the running gear-brakes-wheel alignment-knee action-steering gear-tires-lubrication
-ignition systems-magneto ignition-spark plugs-ignition coils-distributors-automatic spark
control-ignition timing-generators-starters-lighting systems-storage batteries-Diesel engines.
A STANDARD BOOK FOR AUTO MECHANICS AND OPERATORS.
AUDELS MARINE ENGINEERS HANDY BOOK. $4
AN ENTIRELY NEW, MODERN, PRACTICAL TREATISE FOR MARINE ENGINEERS (ALL GRADES),
FIREMEN, OILERS, MACHINISTS, HELPERS AND STUDENTS, WITH CALCULATIONS AND
QUESTIONS AND ANSWERS FOR EXAMINATIONS.
1246 Pages-23 Chapters, logically arranged-fully illustrated and Indexed for Ready Reference.
Practical Information in a handy form covering all branches of Marine Engineering with step by step
solutions on hundreds of problems:
Marine Engineering Physics-Combustion and Fuel-Steam and its Properties-Marine Boilers-Oil
Burners-Fuel Oil-Marine Steam Engines-Engine Governors-Steam Turbines-Diesel Engines-Gas
Engines-Pumps-Refrigeration-Lubrication-Pipefitting-Pipe Covering-Deck Machinery-Ship Pro-
pellers-Marine Electrical Practice-Tables & Data-First Aid-License Requirements-Specimen
Examinations for Merchant Marine Engineer Licenses.
Indispensable for upgrading, examinations and for ready reference. A library in one volume.
AUDELS SHIPFITTERS HANDY BOOK
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288 PAGES OF INFORMATION, INSTRUCTION, PICTURES AND REFERENCE CHARTS, TOGETHER
WITH MANY SHORT CUTS AND TROUBLE SAVERS FOR SHIPFITTERS IN THEIR DAILY ROUTINE.
The inside facts on modern steel shipfitting covered. The seasoned experience of the author who not only
made a close study of the theory of shipbuilding, but whose practical experience includes many years in
the various departments, dealing with all phases of modern steel ship construction. A few of the questions
this book answers: Parts of a steel ship-marine and shipbuilding terms-a shipfitter's duties-the
mold loft-loft room to the hull-mensuration-plan reading-templates-loft work-laying out—
lifting-rivets and riveting-electric welding-gas welding-progress photos.
EVERY SHIPFITTER NEEDS THIS BOOK. NO OTHER TRADE BOOK LIKE IT.
□ PAINTING & DECORATING METHODS....
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A TEXTBOOK FOR APPRENTICE AND JOURNEYMAN. PRODUCED UNDER DIRECTION OF INTER.
NATIONAL ASS'N OF MASTER PAINTERS AND DECORATORS.
Over 300 pages-fully illustrated.
PRACTICAL INFORMATION-EASY TO UNDERSTAND.
The purpose of this book is to help educate men to be first class journeymen house painters and decora-
tors. Painting problems are quickly and easily worked out by its aid.
Covers tools, materials, outside and inside work, floor and wood finishing, paper hanging and calcimining.
A simple, progressive outline for each class of work.
AUDELS GARDENERS & GROWERS GUIDES
EXPERT GUIDANCE FOR BETTER FRUIT, FLOWERS, VEGETABLES.
Here is your opportunity to get a vast amount of expert plans-helps-hints-suggestions-secrets-
short cuts-discoveries for better results.
4 practical help reference volumes-1700 pages-rich, flexible covers-hundreds of illustrations.
Vol. 1-Working, fertilizing, irrigating, draining the soil-284 pages, fully illustrated.
Vol. 2-Good vegetables and market gardening-443 pages, fully illustrated.
Vol. 3-Fine fruit culture, cash crops-492 pages, fully illustrated.
Vol. 4-Beautiful flowers, successful cultivation, propagation. Over 500 pages, fully illustrated.
EXCEPTIONALLY VALUABLE BOOKS FOR SUCCESSFUL GARDENING FOR PLEASURE OR PROFIT.
COMPLETE SET OF 4, $6. SOLD SEPARATELY, $1.50 EACH.
AUDELS ENGINEERS & MECHANICS GUIDES .$12
each $1.50
$3.00
Single volumes I to 7..
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HELPFUL INFORMATION IN HANDY FORM.
For every engineer, mechanic, machinist, electrician, fireman, oiler, engineer student, this Master Sel
is a gold mine of daily, practical helps for workers in every branch of engineering. A self educating study
course for the student, the standard reference work for the chief. Thousands of rules, tables, calculations
and diagrams make it easy to read and learn. Latest inside information on theory and practice of modern
engineering for reference, study and review. Thousands of new short-cuts that make the job easier.
8 pocket volumes with ready reference index, 4500 pages, 7750 illustrations. Easy to read. Highly en-
dorsed. Help in securing engineer's license.
Vol. 1-Engine principles, valve setting, pumps. 470 pages, 847 illus.
Vol. 2-Corliss, uniflow, pumping, contractors engines. 500 pages, 997 illus.
Vol. 3-Locomotive, marine, turbine engines, indicators. 375 pages, 793 illus.
Vol. 4-Gas, gasoline, oil engines, producers, aviation. 475 pages, 640 illus.
Vol. 5-Steam, fuel economy, boiler construction. 525 pages, 755 illus.
Vol. 6-Firing, oil burners, stokers, repairs.. 575 pages, 999 illus.
Vol. 7-Pipe fitting, heating, refrigeration, elevators. 550 pages, 1071 illus.
Vol. 8-Wiring and electrical reference. 1040 pages, 2600 illus.
□AUDELS ANSWERS ON PRACTICAL
ENGINEERING
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QUESTIONS AND ANSWERS COVERING THE FUNDAMENTAL PRINCIPLES GOVERNING PRAC-
TICE OF STEAM ENGINEERING.
288 pages, fully illustrated, handsomely printed and bound.
Answers your questions on air, water, steam, fuel and heat, steam boilers, water tube boilers, the steam
gauge, the safety valve, properties of steam, installation of boilers, management of boilers, engineers'
law, firemen's law, steam engines, the valve and valve gear, the Corliss engine, engine arithmetic, lubri-
cators, installation and operation of engines, steam pumps, injectors, feed water heaters, steam heating,
steam traps, belts, gears and pulleys, steam turbines, refrigeration, practical electricity, elevators.
FOR ENGINEERS, FIREMEN, MACHINISTS.
Audels REFRIGERATION & Air Conditioning Guide $4
4 Books in One; covering basic principles, servicing, operation, repair of:-1. Household Refrigera-
tion, 2. Special Refrigeration Units, 3. Commercial and Industrial Refrigeration, 4. Air Condition-
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1280 Pages, 46 Chapters all Fully Illustrated & Indexed for Ready Reference with Answers to
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AUDELS ELECTRICAL POWER CALCULATIONS.$2
275 TYPICAL PROBLEMS FULLY WORKED OUT.
Gives and explains the mathematical formulae and the fundamental electrical laws for all the everyday,
practical problems in electricity-Ohm's and Kirchhoff's laws for Direct Current-the generation and
application of alternating current-problems in series and parallel circuits-transformers-transmission
lines-electrical machinery. Valuable notes on Radio Circuit Calculation.
With 289 Diagrams, and Tables on Conversion, Wire Gauges and Capacities, etc. Other Data; Symbols,
Formulae. 420 pages, fully diagrammed. Two parts (A.C.-D.C.). Indexed.
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AUDELS NEW ELECTRIC DICTIONARY..
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Valuable as an Encyclopedia of Electricity and as a Dictionary.
AN ABSOLUTE NECESSITY TO EVERY ELECTRICAL WORKER AND STUDENT.
AUDELS NEW RADIOMANS GUIDE.
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A KEY TO THE PRACTICAL UNDERSTANDING OF RADIO. FOR RADIO ENGINEERS, SERVICE-
MEN, AMATEURS.
750 pages, 400 illustrations and diagrams. Size 5 x 6½.
Features: Radio fundamentals and Ohm's Law-physics of sound as related to radio science-electrical
measuring instruments-power supply units-resistors, indicators and condensers-radio transformers
and examples on their designs-broadcasting stations-principles of radio telephony-vacuum tubes-
radio receivers-radio circuit diagrams-receiver construction-radio control systems-loud speakers-
antenna systems-antenna systems (automobile)-phonograph pickups-public address systems-aircraft
radio-marine radio equipment-the radio compass and principle of operation-radio beacons-auto-
matic radio alarms-short wave radio-coil calculations-radio testing-cathode ray oscillographs-
static elimination and radio trouble pointe:s-underwriter's standards-units and tables.
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FOR ENGINEERS, ELECTRICIANS, ALL ELECTRICAL WORKERS, MECHANICS AND STUDENTS.
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electricity. Fully illustrated with diagrams & sketches, also calculations & tables for ready reference.
Helpful questions and answers. Trial tests for practice, study and review. Design, construction, operation
and maintenance of modern electrical machines and appliances. Based on the best knowledge and
experience of applied electricity.
Vol. 1-Principles and rules of electricity, magnetism, armature winding, repairs-700 illustrations-
480 pages.
Vol. 2-Dynamos, D.C. motors, construction, installation, maintenance, trouble shooting-573 illus-
trations-418 pages.
Vol. 3-Electrical testing instruments and tests, storage battery construction and repairs-631 illus-
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Vol. 4-Alternating current principles and diagrams, power factor, alternators, transformers-801
illustrations-484 pages.
Vol. 5-A.C. motors, windings, reconnecting, maintenance, converters, switches, fuses, circuit
breakers-1489 illustrations-498 pages.
Vol. 6-Relays, condensers, regulators, rectifiers, meters, switchboards, power station practice-689
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Vol. 11-Electric mathematics and calculations-700 pages.
Vol. 12-Electric dictionary, 9000 words and terms-550 pages.
COMPLETE IN 12 VOLUMES—EACH VOLUME SOLD SEPARATELY AT $1.50 EACH.
Vol. 7-Wiring-house, light and power, circuits, high tension transmission, plans, calculations, code,
marine wiring practice-1218 illustrations-728 pages.
Vol. 8-Railways, signals, elevators, ignition-1078 illustrations-812 pages.
Vol. 9-Radio, telephone, telegraph, television, motion pictures-793 illustrations-576 pages.
Vol. 10-Refrigeration, illumination, welding, x-ray, modern electrical appliances, index-1084 lus-
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Audels REFRIGERATION & Air Conditioning Guide
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Audels SHEET METAL WORKERS Handy Book
Audels SHEET METAL PATTERN LAYOUTS
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Audels MATHEMATICS and CALCULATIONS
Audels MACHINISTS & TOOLMAKERS Handy Book
Audels DIESEL ENGINE MANUAL
Audels MECHANICAL Dictionary
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