Improvements in or applicable to Street-car Motors.
Year: 1890

page_text: Date of Application, 22nd Apr., 1890-Accepted, 20th Sept., 1890
COMPLETE SPECIFICATION.
Improvements in or applicable to Street-car Motors.
I, WILLIAM EDGAR PRALL, residing at 920 16th Street, Northwest, in the City of
Washington, District of Columbia, United States of America, Mechanical Engineer,
do hereby declare the nature of my invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:- 1
Numerals 1, 1, indicate I beams secured to brackets 2 which embrace axles 3,
which latter are connected to and support the car body upon the main-wheels in any
approved manner. 4 denotes a water reservoir preferably protected against radiation
of heat by a non-conducting covering and supported in any convenient manner, as
by brackets 5, of which there are two, one being secured to each of the beams 1,
as indicated. This reservoir communicates by a pipe 6 with a generator pipe coil
suitably disposed within a combustion chamber 8, and over or about a perforated
burner cylinder 9. Liquid, gaseous or vaporized fuel is supplied through a pipe 10
having cock 17 and communicating with a source of supply as an oil tank, which may
be conveniently located on the top of the car. The upper end of the steam generator
represented in the present instance by a coil preferably made of copper pipe communi-
cates by means of pipe 11 with the valve chest 12 of a steam engine 13 supported
on the beams 1, or in any approved manner. 14 is an exhaust pipe leading to a
series of condensers 15, which have communication with the open air, and preferably
above the car.
16 is a valve or cock for closing the pipe, and 18 is a second cock in said pipe.
Between the two latter cocks is a branch steam pipe 19 leading back and connecting
with a coil in the water tank and continued thence back again and connected with
steam pipe 11 at a point between cock 18 and the engine.
The water tank is situated at about the same level as the generator and connected
with the bottom thereof by an ordinary pipe, and the generator is also formed of
convolutions of pipe rising near to or above the highest level in the tank. This
construction combined with the herein described devices for controlling the fire and
regulating the discharge of steam, one or both, allows a free communication between
generator and tank during the production of steam without danger of high pressure,
and provides for a method of operation which consists in conducting water into the
bottom of the generator continuously, except when it is prevented by the backward
pressure of steam, returning surplus steam to a heating pipe in the tank and auto-
matically shutting off the steam supply when a steam pressure above a desired limit
is reached.
The steam space of the generator is provided with a branch leading to a diaphragm
chamber forming a part of an automatic valve operating apparatus of well known
construction with the fuel supply pipe. The water supply pipe 6 is furnished with a
stop cock 20.
The operation of the above described devices is as follows:-
Oil and water being supplied to their respective tanks, the cocks 16 and 20 are
opened and the fuel issuing from pipe 10 at its end within the burner is ignited, air
being freely admitted to promote combustion, and the products of combustion after
circulating about the coils or other parts of the generator escape through a suitable
exit pipe as 21. Steam is thereby generated and then conducted to the engine to
drive the same in usual manner.
The pipe 11 provided with a cut-off cock 16 or 18 may be used to direct steam
direct to the engine. It is also contemplated by the invention that steam may be
conducted by a pipe 19, leading to the water tank, and thence to the engine, a cock
such as either 22 or 23 being used as a cut-off. In the construction shown, the

page_text: closing of cock 18 provides for thus conveying the steam to the tank and thence to
the engine. For this single purpose, however, the portions of pipe between the
extremities of pipe 19 might be permanently closed, or entirely removed, and pipe 19
thus adopted as a means of communication from the generator to the engine by way
of the tank. The construction illustrated is, however, preferred, as by it steam may
be supplied, either directly or indirectly to the engine, or by suitably regulating the
cocks shown a part can be sent direct to the engine, and a part by the way of the
tank. It is one of the objects of the invention, to keep the water in the supply tank
hot, by the circulation described. The heat of the generator may also be maintained
by the burner and steam can be instantaneously generated at will by admitting heated
water into the highly heated coil generator by simply opening the steam cut-off cock
and thus reducing the back pressure in the generator and permitting the water to
enter it, and it is one of the important features of the improvement that the generator
coil shall be capable of storing a large amount of heat and transferring it quickly to
water entering the same, and also that this supply of water shall be automatically.
regulated by the pressure therein. The automatic regulation of the fuel supply, the
thorough and noiseless condensation of exhaust steam by perforated condensers, or
their equivalents, and the convenient and efficient control of the cut-off cocks in the
steam and fuel supply pipes by the use of the braking apparatus are also important
features in the relations pointed out.
For the purposes of my improvement any form of condenser that will prevent the
issue of a cloud of steam and a noisy discharge will suffice, but 1 prefer to employ
one which consists of the frusta of hollow cones supported in series at a small distance
apart, as indicated in Figure 4. The steam escaping from the exhaust pipe will create
a current in the direction of the axis of the frusta and will draw air in between them
and become mingled therewith and condensed in a quiet and efficient manner.
The
water of condensation can be received in a receptacle on the roof of the car and
disposed of by pipes, or in any suitable manner.
As
The cocks can be connected to be operated from any desired part of the car.
for example, cocks 16 and 17 may be connected by means of cranks to a rod leading
to the platform and loosely joined to one arm of a bell crank lever, the other being
arranged in the path of the arm 30 fixed on a brake spindle or rod 31. As represented
this, rod is made movable vertically in brackets connected to the car and is provided.
with a screw threaded connection with a socket in a bracket in such manner that it
can be lowered to carry the projection 30 against the horizontal arm of the bell crank
lever to open the cocks, the open connection of the valves being indicated in Figure 1.
On returning the screw threaded rod in a reverse direction the arm or projection 30
is lifted from the bell crank lever and the cocks are closed by a spring 32. The
continued revolution of the rod after the closing of the cocks applies the brake 33 to
the car wheels by means of the connecting rod 34 and chain 35, the latter being
wound upon the foot of the rod in such manner as to draw the brake upon the surface
of the wheels, the spring 36 being also at the same time. compressed, which spring
serves to release the brake from the wheels when the chain is unwound by a reverse
movement of the rod 31. It is characteristic of this part of my improvement that.
the brake and the cocks can be simultaneously operated from the car at will by the
rods or well known equivalents, both to apply the brake and open or close the cocks
by the same manipulation so that the brakeman suitably shuts off or opens the steam
and fuel supply pipes by the braking operation.
The car wheel can be geared to the engine by means of a gear 24 made fast to an
axle and engaging a pinion 25 revolving ou a bracket stud and connected to a
pulley 26, which pulley is geared to the engine by means of a pulley 27 and a chain
or cord '28, the pulley 27 being connected to the engine in any usual or suitable
way. The forward and rear car wheels can be geared together by chain wheels 27*
as indicated in Fig. 3.
It will be understood that the particular form and arrangement of the tanks,
heating coils, steam generator, combustion chamber, burner, gears, valve rods, brake,

page_text: rod, are not of the gist of this invention, except as hereinafter pointed out, as these
can be varied by mechanical skill in many particulars without departure from my
invention, or from its principles of operation.
The particular means of operating the cocks may be varied by extending the rods
to other parts of the car, and by operating one or more cocks by a single rod, which
may or may not be the brake rod, or other means than rods known in the art can be
resorted to. The precise location of the various cocks is generally immaterial. In
like manner equivalent forms can be adopted for the generator.
It is, however, important that a large steam generating surface be exposed to the
products of combustion to secure prompt production of steam. It is also desirable
that means be provided for maintaining the heat of the water in the tank and utilizing
surplus steam for the purpose, and all parts holding or conveying hot fluids may well
be protected by non-conducting coverings. It will, of course, be understood that the
fuel supply pipe may at its outer end be provided, if desired, with any of the usual
appliances, such as a drip pan, air distributor.and damper and relighting burner, and
also that a secondary air supply may be provided, and it is not deemed necessary to
describe and illustrate such matters. It will be further understood that the above
described apparatus is suitable for propelling other vehicles than street cars.
The water tank is preferably located under the car, but not necessarily and this is
true also of the generator and engine. If the tank be at much higher lever than the
generator it will in some cases be desirable to reduce the size of the pipe 6 below
from about one-fourth to one-half inches to check the flow of water to the generator.
In case the pipe be too small for the ready return of the water to the tank by back
pressure an ordinary by-pass pipe 37 with check valve 38 may be used. The pipe 6
inay be provided with a cock 39, which will be convenient if found necessary to close
the pipe in making repairs, or for any reason, and obviously it can be used to regulate
the amount of water allowed to flow through the pipe. It is according to the present
improvement, however, to maintain an open connection between the generator and
boiler, and to use pressure in the generator to prevent too large a supply of water.
It is to be understood however that normally the pressure in the generator is
insufficient to prevent the inflow of water, and that this inflow is totally prevented
only when the generator pressure is raised above a normal or working degree, as by
continuing the fires after the steam pipe has been closed. Besides the uses named
for cock 39, it could be used to entirely shut off the water supply for the purpose of
bringing the engine to rest, but preferably a cock for this purpose is provided in
pipe 11, and it may be variously located therein, or in a modification thereof for some
of the purposes of this invention. Thus, it would be possible to direct all live steam
through pipe 19, and use either cock 16, 22, or 23 to shut off steam from the engine,
and it is noted as coming within the invention that steam can be discharged into
tank 5, and in which case it may, if desired, be taken thence to the engine. Pipe 37
located back of the cut-off cock will be used in this case in order that pressure from
the tank may be kept from the engine when said cock is closed. The pipe 37 is
provided with a cock 38, and pipe 19 may be provided with a check valve 39.
Dotted extensions of parts of pipe 19 at the tank indicates a suitable arrangement
for this operation.
The constant open condition of the pipe 6 adapts it to instantly supply water for
production of steam when the relation of pressure in the generator is normal, and
the construction of the generator, of pipe, or of other like form, whereby its whole
extent is thoroughly exposed to the heat of the fire, and the character of the fuel
which adapts it to be instantaneously supplied and lighted, or cut off, all combine to
adapt the apparatus to the exigencies of street car service. And the preferred
construction whereby the fuel, and steam supply valves, and the brake are all so
connected as to be operated by one device of simple and familiar character combined
with the features above enumerated further adapt the apparatus for street cars and
the like and the means of noiselessly discharging either live or exhaust steam
increases its fitness for the use named. Such devices are not, however, claimed
herein except in the combinations pointed out. A like remark is applicable to other

page_text: portions of the apparatus, such as the brake for example, it being obvious that any
well known forms and those applicable to both front and back wheels may be
employed.
The burner tube may be made of asbestos, or of like material in any approved
form, and its combustion chamber may be of other form than rectangular, and its
exit pipo may have a branch or branches running through the car for heating
purposes.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim, is:-
--
1. In a steam apparatus for propelling vehicles, the combination of the water tank,
steam generator and steam engine, and the fuel burner, the steam pipe leading from
the generator to the engine being provided with a valved branch located between the
generator and the main pipe, said branch being adapted to convey steam to the water
tank, substantially as set forth.
2. In a steam apparatus for propelling vehicles, the combination of the water tank,
steam generator and steam engine, and the fuel burner, the steam pipe leading from
the generator to the engine being provided with a valved branch located between the
generator and said valve in the main pipe, said branch being adapted to convey
steam to the water tank and through a conduit in the tank, and thence through a return
branch to the main steam pipe beyond the aforesaid valve in said pipe between the
ends of the outgoing and returning branch pipes, substantially as set forth.
3. The combination of the steam generator and steam engine connected by a pipe
or conduit, a cock in said pipe, a rod connecting said cock to a brake rod, said rod
. extending to the platform or like part of the car, a brake and connections between it
and said brake rod, whereby the same rod can be manipulated to shut off the
car, a brake and connections between it and said brake-rod, whereby the same rod can
be manipulated to shut off steam and apply a brake, substantially as set forth.
4. The combination of the steam generator and steam engine connected by a pipe
or conduit, a valve in said pipe, a rod connecting said valve to a brake-rod a fuel
supply pipe having a valve also connected to said brake, a brake and connections
between it and said brake rod, whereby the same rod can he manipulated to shut off
both steam and fuel and to apply a brake, substantially as set forth.
5. The combination of a water tank, generating coil and steam engine, the
tank and generator communicating by an unobstructed water supply pipe, and a
steam pipe leading from the generator through said water tank to the engine,
substantially as set forth.
6. The combination of a tank and generating coil located on or about the same
level and communicating by an unobstructed pipe opening into the tank below the water
level, a burner, and means for automatically reducing the fire, substantially as set
forth.
7. The combination of a tank and generating coil located on or about the same
level and communicating by an unobstructed pipe opening into the tank below the
water level, a burner, and means for directing surplus steam to the tank to heat the
same, substantially as set forth.
8. The method of generating steam which consists in keeping an open com-
munication between the water tank and generator, conducting water into said
generator arresting the flow by back pressure above the normal or working pressure,
and automatically reducing the fire to prevent excessive steam pressure, substantially
as set forth.
9. The method of generating steain which consists in continuously conducting
water into a steam generator, and conducting the surplus steam to the water
tank, and automatically controlling the generation of steam, substantially as set
forth.
10. The method of generating steam which consists in maintaining open com-
munication between the generator and the water supplying tank, and automatically

page_text: varying the amount of water supplied to the generator by generating therein a steam
pressure above the normal, substantially as set forth.
11. The combination of a generator composed of coiled pipe or equivalent, a
water tank in open communication therewith at a point below the water level, a steam
pipe having a cut-off cock, and an engine, substantially as set forth.
12. In a steam apparatus for propelling vehicles, the combination of the water
tank, steam generator and steam engine, and the fuel burner, the steam pipe leading
from the generator to the engine being provided with a valved branch located between
the generator and said valve in the main pipe, said branch being adapted to convey
steam to the water tank, and a condenser whereby steam may be noiselessely con-
densed, substantially as set forth..
13. The combination of the brake mechanism and the fuel supply pipe provided
with a cock, both the brake and the cock being connected to and operated by a
single device, such as a cranked rod and connecting devices, substantially as set
forth.
14. The combination of the brake mechanism, the oil supply pipe and its cock,
the steam supply pipe and its cock and the brake all being connected to and
operated by a single device, such as a cranked rod and connecting devices, substantially
as set forth.
'
15. In combination with a street car, the hot water tank, the steam coil or
generator, the pipe of the coil commnicating with a pipe extending to an engine and
provided with a valve or cock for controlling the steam supply to the engine, the oil
tank provided with a pipe to convey oil to the burner, and having a cock to control
the flow of oil, steam engine, the steam condensers and a brake, the oil and steam cocks
being controlled by a lever, which lever also operates the car brake, substantially as set
forth.
16. In combination with a street car, the hot water pressure storage tank, the
coiled pipe generator, the fuel supply tank and its pipe, the latter being pro-
vided with an automatically regulated cut-off, and the burner, substantially as
set forth.
Dated this 5th day of April 1890.
WILLIAM EDGAR PRALL..