Calvin F. (Calvin Franklin) Swingle.

Cyclopedia of locomotive engineering, with examination questions and answers; a practical manual on the construction, care and management of modern locomotives, including boiler construction, valves and valve gears, indicators, locomotive equipments, including headlights and mechanical stokers. Spec online

. (page 18 of 42)
Online LibraryCalvin F. (Calvin Franklin) SwingleCyclopedia of locomotive engineering, with examination questions and answers; a practical manual on the construction, care and management of modern locomotives, including boiler construction, valves and valve gears, indicators, locomotive equipments, including headlights and mechanical stokers. Spec → online text (page 18 of 42)
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425. How are the cylinders of the Baldwin balanced
compound located?

426. What type of valve is used on these engines?

427. Where are the valves located?

428. Where are the high-pressure cylinders lo-
cated ?

429. At what angle are the cranks set?

430. Describe briefly the action of the steam in this
engine.

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COMPOUND LOCOMOTIVES 335

431. How are the cylinders of the American Loco-
notive Company's balanced compound located?

432. How is a uniform turning moment attained in
;his engine?

433. Mention the advantages that the balanced com-
pound possesses over other types of compound loco-
motives.

434. Why does the tandem compound appear to be
the ideal locomotive?

435. What is one of the main objections to this type
of compound locomotive?

436. What kind of handling does a compound engine
require?

437. What knowledge is necessary for the engineer
in order that he may successfully operate a compound
engine?

438. What can be said regarding the tandem com-
pound built by the American Locomotive Co.?

439. How are the valves arranged on this engine?

440. What is the function of the starting valve?

441. How should a compound locomotive be
lufiricated ?

442. How are the cylinders placed in the Baldwin
tandem compound?

443. What about the cylinders and valve chests of
this engine?

444. What kind of a valve has this engine?

445. How many cylinders has a cross compound, and
how are they located ?

446. What is the purpose of the intercepting valve?

447. What is the function of the automatic reducing
valve?

448. How is the steam for operating these valves
supplied?

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336 LOCOMOTIVE ENGINEERING

449. How is the receiver pressure governed?

450. What are the by-pass valves for? .

451. What precautions should be observed regard-
ing water on these engines?

452. What about the oil dash pot?

453. What should be done when drifting?

454. What should be done with the separate exhaust
valve?

455. Should the engine refuse to move when the
throttle is opened, what would be the probable cause?

456. How may it be ascertained which one of these
valves is stuck?

457. How may the stuck valve be loosened?

458. In what position should the dampers be wheo
drifting?



yGoogk



CHAPTER IX

INJECTORS, STEAM GAUGES. POP VALVES AND
OTHER 'fittings

Injaetors. The proper method of feeding water to a
boiler while in operation under a high pressure, is a
problem that demands the constant and earnest atten-^
tion of the engineer, not only as a matter of personal
safety, but the efficiency of the boiler depends in a
large measure upon the manner in which the feed
water enters the boiler. Theoretically the supply
should just equal the demand at all times; that is to
say, there should be a constant ingoing of water into
the boiler during all the* time that the fire is active,
and the volume of water entering the boiler should
exactly equal the volume of water that is being evap-
orated within the boiler. But these conditions are
hardly possible in practice. Especially is this so in
locomotive practice, where the service differs so
greatly from marine or stationary service. The
judicious use of the injector on a locomotive is a sub-
ject that engineers and firemen should study to famil-
iarize themselves with.

The importance of this matter is shown in the fol-
lowing extract from the' report of a committee of the
Traveling Engineers' Association: "It would hardly
cut any figure how careful an engineer might be in the
handling of his train, with the skill he uses in regu-
lating speed or in the adjustment of the throttle and
the reverse lever, if the water was not put into the
boiler at the right time and the right place. In our

33 7 Digitized by GoOglC



338



LOCOMOTIVE ENGINEERING



experience we have known alrriost remarkable resuiti
to be brought about in an engine's fuel performance
by explaining this matter to engineers who perhaps
had not given it the thought that the subject deserves."
It will be noticed that the committee emphasizes the
importance of ''putting the water into the boiler at the
.right time and the right place," if economy in fuel
is to be attained, and this certainly is a worthy object
tor every locomotive engineer to have in view at all
times.

Now as to the **right time" for puttii.^ water into a




FiGTmB 165
Original Form op the Giffard Injectob
locomotive boiler: A good time to use the injector to
advantage is while standing at a station. To this end,
't is the practice of some engineers when approaching
a stopping point, to allow the water level to drop
below the normal point, thus utilizing the heat already
stored in the water that is in the boiler to enable them
to get into the station. When the throttle is closed
(or making the stop the injector may be started, and
much of the heat that would otherwise be wasted at

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INJECTORS, STEAM GAUGES, ETC. 330

the pop valve will be utilized in forcing a new supply
of water into the boiler. Another **right** time and
place to use the injector is just after passing the sum-
mit of a long hill, when the throttle can be eased off.
This will prevent the pop from rising so freely on the
down grade, and thus another source of economy will
be taken advantage of. There are many other "right'*
time^ and places for using the injector, that an observ-
ant and careful engineer will, by a little thinking, be
enabled to figure out for himself. Much, of course,
depends upon the kind of an injector a man has on his
engine. If it has a wide range of capacities, and can
be throttled so as to feed a very small jet without
breaking, it may be used almost continuously, espe-
cially if the track is straight, and there are hot very
many heavy grades. The modern injector, as it is fur-
nished at the present time by the leading manufac-
turers, approaches very nearly to being a perfect boiler
feeder for locomotives Ever since the time of the
invention of the injector in 1858 by that eminent French
engineer Henri Giffard, and its introduction into this
country Jn i860 by Wm. Sellers & Co., of Philadelphia,
it has been constantly improved upon, and developed
by various inventors and manufacturers, and it is
to-day, without doubt, the most simple, the most eco-
nomical, and the best device for feeding water into
locomotive boilers. As a short study of the philosophy
of the action of the injector is not only useful, but
should be interesting to engineers and firemen, a
space will be devoted to this subject. The leading
types of injectors and inspirators will also be described
and illustrated.
How an Injector Works.* How can an injector lift

♦Stxlcland L. Kneass.C. E., from Sellers' Hand-Book of Injectors.

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340 LOCOMOTIVE ENGINEERING

and force large volumes of water into the boiler,
against the same or even higher pressure than that of
the steam?'*

"An injector works because the steam imparts suffi-
cient velocity to the water to overcome the pressure of
the boiler/'

This is a statement of fact; to explain the action,
we will take up the important parts of the question
separately.

Why should an injector work? Let us assume that
the boiler pressure is i8o pounds — that is to say, every
square inch of the sheets, top and bottom, receives an



Figure 166
The Self-Actinq Injector, Class N Improved P. R. R. Standard

internal pressure of i8o pounds. If the thermometer
is placed inside, it is found that both the water and the
steam are at the same temperature, 379 deg. But the
steam contains more heat than the water, because
after water is heated, more coal must be burned to
break up the drops of water to change them into steam;
this heat is stored in the steam and represents work
done by the burning of the coal. Steam not only
exerts a pressure of 180 pounds per square inch, but



INJECTORS, STEAM GAUGES, ETC. 341

also can expand eight to twenty-six times its original
volume, depending upon whether it exhausts into the
air or into a partial vacuum; water under the same
pressure would be discharged in a solid jet and with-
out expansion. Either steam or water can be used in
the cylinder of an engine or to drive the vanes ot a
steam or water turbine, but one pound of steam is
capable of much more work than one pound-weight of
water, on account of the heat which has been used to
change it into steam. This is easily seen by compar-
ing the velocities of discharge from a steam nozzle and
a water nozzle under 180 pounds pressure; steam would
expand while issuing, reaching at the end of the nozzle
a velocity of about 3600 feet per second, while the
water, having no expansion, would have a velocity of
only 164 feet per second, about ^ of that of the
steam. The same weight of steam discharging per
second would therefore have vastly more power for
doing work than the water jet.

If a steam or water jet comes in contact with a body
in front of it, the tendency is to drive the body for-
ward. The force which tends to move the body is
called "momentum,'* and is equal to the weight of
water or steam discharged by the jet in one second,
multiplied by its velocity per second. If i pound of
both the water and the steam are discharged per
second, the ''momentum'* of the steam jet is 3600;
because i multiplied by 3600 = 3600; the momentum
of the water jet is 164. If the water jet discharged
about twenty-two pounds per second, its momentum
would be the same as that of the steam, because 22
multiplied by 164 is nearly 3600. The two jets are dis-
charged under the same pressure, but the steam has
twenty-two times as much "momentum" or force as



342 LOCOMOTIVE ENGINEERING

,.he water jet; it could, therefore, easily enter a boiler
at i8o pounds pressure if we could reduce it to the size
^f the hole of the water nozzle.

How ought an injector to work? Here a practical
difficulty is reached. A steam jet 6 in. from the noz-
zle is much larger than at the opening, and it would
appear almost impossible to make it enter a smaller
tube. Even at the narrowest part of the nozzle it is
more than sixteen times larger in diameter than a



Figure 157
The Self-acting Injector, Class M Improved

water jet discharging the same weight per second;
therefore, if the steam is changed to water without
reducing its velocity, it would pass through a hole one-
sixteenth the diameter of the "steam nozzle'' at a
velocity of 3600 feet per second. The simplest and
best way to reduce its size is to condense it, and to
use water for this purpose, especially as water is
needed in the boiler. To condense the steam and
utilize its velocity, the water must be brought into
close contact with it, without interfesine; jwith the



1

INJECTORS, STEAM GAUGES, ETC. 343

direct line of discharge; a funnel or ''combining tube**
suitably placed will compel water to enter evenly all
around the steam jet. The mouth of this funnel must !
not be too large, or too much water will enter and
swamp the jet; if too small, insufficient water will
enter to condense the steam. The effect of condens-
ing the steam is to reduce the diameter of the jet;
therefore the funnel or combining tube must be a
smooth, converging taper, to lead the combined jet of
water and condensed steam into the smaller hole of
the delivery tube. The effect of the impact of the
steam is to give the water its momentum, so that a
solid stream shall issue from the lower end of the tube.
Each little drop of entering water is driven ahead faster
and faster by the vast number of little atoms of steam
moving hundreds of times as rapidly, until the steam
and water thoroughly combine into one swiftly-moving
jet of water and condensed steam, which contracts suffi-
ciently in diameter to enter the smaller delivery tube.

Why does the jet enter the boiler? The combined
jet now passes from the end of the combining tube into
the delivery tube; why does it enter the boiler?

If a pipe shaped like a fire-hose nozzle or a ''delivery
tube'* is connected to a t^nk or boiler carrying 180
pounds, the water will issue in a solid jet with a
velocity of about 164 feet per second; or, if we could
force water into the tube at a speed of 164 feet per
second at the same part of the tube, this water would
enter and fill up the boiler or tank against 180 pounds
pressure. Therefore to enter the boiler the combined
jet of water and steam issuing from the combining tube
must have a velocity of at least 164 feet per second.

Now, what is the velocity of the combined jet at the
lower end of the combining tube? If the>steam noz-'-'

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>S44 LOCOMOTIVE ENGINEERING

discharges one pound per second at 3600 feet velocity,
the momentum of the steam is i multiplied by 3600, or
3600. If the vacuum caused by the condensation o£
the steam lifts and draws into the combining tube ten
pounds of water per second at a velocity of forty feet,
its monientum is 400; and that of the combined jet is
3600 added to 400, or 4000. The weight of the com-
bined jet is eleven pounds, and at the time of entering
the delivery tube its velocity ought to be equal to 4000
divided by 11, or 366 feet per second; but as the water
and the steam do not meet in precisely the line of dis-
charge there is a loss of momentum, and the velocity
in the delivery tube is only 198 feet per second. But
the jet only needs a velocity of 164 feet to enter the
boiler or tank carrying 180 pounds pressure, therefore
the actual jet in the delivery tube is able to overcome a
pressure of 206 pounds per square inch, or twenty-six
pounds above that of the steam, because the velocity
of a jet of water under a head or pressure of 206 pounds
would be 198 feet per second. This excess is more
than sufficient to overcome the friction of the delivery
piping and the resistance of the main check valve.
Therefore:

**The action of the injector is due to the high velocity
with which a jet of steam strikes the water entering
the combining tube, imparting to it its momentum and
forming with it during condensation a continuous jet
of smaller diameter, having sufficient velocity to over-
come the pressure of the boiler."

The Sellers Improved Self-acting Injector. Description.

This injector is simply constructed and contains few

operating parts. The lever is used in starting only, and

the water valve for regulation of the delivery. It

elf-adjusting, with fixed nozzle, and rc^^ts ^to-



INJECTORS, STEAM GAUGES, ETC. 345

matically. All the valve seats that may need refac-
ing can be removed; the body is not subject to wear
and will last a lifetime.

The action is as follows: Steam from the boiler is
admitted to the lifting nozzle by drawing the starting
lever (33) about one inch, without withdrawing the
plug on the end of the spindle (7) from the central
part of the steam nozzle (3). Steam then passes
through the small diagonal-drilled holes and discharges
by the outside nozzle, through the upper part of the



Figure 158
The Self-Acting Injector, Class N Improved
p. r. r. standard sellers standard form

combining tube (2) and into the overflow chamber, lifts
the overflow valve (30), and issues from the waste pipe
(29). When water is lifted the starting lever (33) is
drawn back, opening the forcing steam nozzle (3), aud
the full supply of steam discharges into the combining
tube, forcing the water through the delivery tube into
the boiler pipe.

At high steam pressure there is a tendency in all
injectors having an overflow to produoe a vacuum in

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346 LOCOMOTIVE ENGINEERING

the chamber (25). In the Improved Self-Acting
Injector this is utilized to draw an additional supply
of water into the combining tube by opening the inlet
valve (42); the water is forced by the jet into the
boiler, increasing the capacity about 20 per cent.

The water-regulating valve (40) is used only to adjust
the capacity to suit the needs of the boiler. The range
is unusually large.



Figure 159

Sblf-Acting Injector, Class M Improved

special form, interchangeable with monitor, ohio, etc.

The cam lever (34) is turned toward the steam pipe
to prevent the opening of the overflow valve when it is
desired to use the injector as a heater or to clean the
strainer. The joint between the body (25) and the
waste-pipe (29) is not subject to other pressure than
that due to the discharging steam and water during
starting; the metal faces should be kept clean and the
retaining nut (32) screwed up tight.

To tighten up the gland of the steam spindle, push
in the starting lever (33) to end of stroke, remove the

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INJECTORS, STEAM GAUGES, ETC. 347

little nut (5) and draw back the lever (33). This frees
the crosshead (8) and links (15), which can be swung
out o£ the way, and the follower (12) tightened on the
packing to make the gland steam-tight.

The Improved Self-Acting Injector is specially
adapted to railroad service, as its efficient, positive
action and wide range of capacities at 200 pounds steam
render its application to high-pressure locomotive
boilers very advantageous. It will work from the



Figure 100
Sblf-Acting Injector, Class P, Special 10 J and 11 J Only

highest steam pressures used on locomotives down to
35 pounds steam without adjustment and without wast-
ing at the overflow, and by regulating the water-supply
valve on the injector it can be operated at 15 pounds.
As it restarts instantly under all conditions of service,
it can always be depended upon to force all the water
into the boiler, so that the engineer can give his whole
attention to his other duties.

Sizes of Injectors for Locomotives.* In determining
the size of injector required for .locomotives, the size

•Vr^ni "Praotio* and Theory of the Injector." Wiley & Sons, New York.



J



348



LOCOMOTIVE ENGINEERING



of the cylinder is usually taken as the standard,
although the diameter of the boiler and the kind of
service for which the locomotive is intended has a
modifying influence.

Table 17



Diam. of


Size of


' Diam.


Size of


Diam.


Size of


Diam.


Size of


Oyl.,
inches


Injector


of Cyl.,
inches


Injector


of CyL,
inches


Injector


of CyL,
inches


Injector


9


4ft


13


5,^


17


7i


21


9it


10


4A


14


6i


18


8i


22


10


11


5A


15


6i


19


8it


23


10


12


5tV


16


7i

1


20


9i


24
25
26


Hi

11

12A



t Use next size larger with specially large boiler.

Table 18

Improved Self-Acting Injector

Maximum and Minimum Capacities, All Classes

Gallons per Hour— 6 Feet Lift. {7% Gallons = 1 Ouhic Foot.)



Size


60 Lbs. Steam |


120 Lbs


Steam


180 Lbs. Steam


300 Lbs. Steam


Max.


Min.


Max.


Min.


Max.


Min.


Max.


Min.


t4A


427


158


562


208


517


345


500


350


.6A
6\


667


247


907


340


1027


395


1035


455


967


358


1320


489


1492


568


1516


667


7-


1290


477


1755


650


1987


757


2010


885


8"


1657


613


2257


835


2550


970


2587


1138


9i
104


2070


766


2820


1044


3150


1197


3187


1402


2535


938


3450


1280


3900


1482


3952


1740


11


3037


1124


4132


1530


4672


1775


4725


2079


12A


3650


1351


4968


1847


5616


2134


5700


2450



t Class N. Imp. not made 4 A size; only supplied in Classes L, M, and N.

Things to be Eemembered. With LooomotiyeB Carrying
High Steam Pressure (180 to 225 Fonnds). Set the

injector just above the top water level of the tank.
At 8 feet lift, 200 pounds, the capacity is about 10 per
cent less than the list.

Cold water is best for the injector. Hot water
reduces the life and efficiency. At 120 deg. the capac*

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INJECTORS, STEAM GAUGES, ETC. 349

ity IS about one-third below list given in the table.
The range of capacities is reduced and no injector lifts
as promptly.

Use large suction pipe and tank valve connections.
If the diameter is increased one size, the gain in capac-
ity is from 5 to 10 per cent.

Use large strainer with small holes. Small strainers
require frequent cleaning. If the holes are large, cin-
ders and coal pa s
through and wear the
tubes. If the strainer
is too small, the in-
jector does not give
full- capacity. Be
sure that the gasket
between hose and
suction pipe is not
squeezed so as to
close opening.

Suction pipe must
be absolutely tight. Figure 161

Any leak of air re- Locomotive Feed- Water Strainer
duces the capacity for right- or left-hand side of
and makes the over- engine

flow valve jump.

Delivery pipe and main check valve must be of
ample area. If an injector gives high back pressure, it
is using too much steam. If the delivery opening is
too small, the power of the injector is wasted in in-
creased friction in the pipes.

Take good care of the injector. Keep all glands
steam-tight, and watch carefully for leaks in the suc-
tion pipe. Do not force the steam valve hard against
its scat; close the valve gently. Start the injector ir



3SO



LOCOMOTIVE ENGINEERING



the same way; at very high pressure the delivery pipt
is liable to burst if the lever starting valve is jerked
open. Keep the injector clean and report at once if
not working properly. Do not run with the water-
regulating valve wide open all the time.

List of Parts, Self-Acting Injector,
Class N Improved



1. Delivery Tube.

2. Combining Tube.

3. Steam Nozzles.

5. Spindle Nut.

6. Steam Stuffing Box.

7. Spindle.

8. Cross-Head. '
10. Water Stuffing Box.

Follower.

Packing Ring.

Lock Nut.

Follower for No. 10.

Links.

Packing Rin^.

Plain i&J*""

R«d«- |pi^T'
Check Valve.
Guide for No. 20.
Plain J Unions for
Reduc. I Iron Pipes.



11.
12.
13.
14.
16.
16.

19.
19a.

20.
22.
23.
23a.



24. Coupling Nuts.

25. Injector Bodj.
27. Wrench.

29. Waste Pipe.

30. Waste Valve.

31. Waste Valve Cam.

32. Jam Nut for No. 2».

33. Starting Lever.

34. Cam Lever.

35. Pin, Nos. 38 and 33.

36. Cam Shaft.

37. Washer on 36.

38. Collar and Index.

39. Fimnel.

40. Plug Water Valve.

41. Regulating Handle.

42. Inlet Valve.
57. Closed Overflow

Connection.



List of Parts, Self-Acting Injectok,
Class M Improved



L



1. Delivery Tube.

2. Combinmg Tube.

3. Steam Nozzles.

5. Spindle Nut.

6. Steam Stuffing Box.

7. Spindle.

8. Cross-Head.

10. Water Stuffing Box.

11. Follower.

12. Packing Ring.

13. Lock Nut.

14. Follower for No. 10.

15. Links.

16. Packing Ring.



19. Plain Sf^tl°'
19a. Reduc. j Copper

20. Check Valve.

22. Guide for No. 20.

23. Plam j Unions for
23a. Re,duc. ) Iron Pipes.

24. Coupling Nut.

25. Injector Body.
27. Wrench.

29. Waste Pipe.

30. Waste Valve.

31. Guide for No. 30,

32. Jam Nut for 31j^[^



inje;ctors, steam gauges, etc. 351



83.


Starting Lever.


57.


Closed Overflow


34.


Cam Lever.




Connection.


35.


Pin, Nos. 38 and 33.


78.


Guide for Overflow Valve


36.


Pin through 31 and 34.
Collar and Index.




75.


38.


74.


Heater Stem.


39.


Funnel.


75.


Overflow Valve.


40.


Plug Water Valve.


76.


Follower.


41.


Regulating Handle.


77.


Pack Ring in 73,


42.


Inlet Valve.


78.


Heater Lever.



The Sellers' Self -Acting Injector. Class P— Sizes 10>^

and 11 J^. This is a special form of body, designed to
be applied to the back-head of the locomotive boiler,
with the starting lever and water regulating valve
placed directly over the brake valve and within con-
venient reach when the engineer is seated. The
coupling nuts and sizes of the pipe are Pennsylvania
Railroad (Sellers') Standard, but the branches are
located so as to avoid t)ie fire-door and boiler attach-
ments.
Hints to be Read Before Connecting the Injector.

1. Blow out all pipes carefully with steam before
attaching the injector, tapping the pipe with a ham-
mer in order to loosen all the scale.

2. When drip pipe is attached close to overflow of
injector, it must be same size as given in table.

3. Always use a dry pipe attachment to insure per-
fectly dry steam.

4. The diameter of the strainer should be large
enough to give an ample supply of water even when
some of the holes are choked. ^

5. Keep all valves steam-tight; all leaks tend to
increase rapidIy,'owing to the velocity with which
steam passes through the smallest opening.

6. Keep the steam pipe and chamber free from dirt



Online LibraryCalvin F. (Calvin Franklin) SwingleCyclopedia of locomotive engineering, with examination questions and answers; a practical manual on the construction, care and management of modern locomotives, including boiler construction, valves and valve gears, indicators, locomotive equipments, including headlights and mechanical stokers. Spec → online text (page 18 of 42)