Improvements in or relating to Apparatus for Propelling Street Cars, applicable also for Propelling other Vehicles.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in or relating to Apparatus for Propelling Street
Cars, applicable also for Propelling other Vehicles.
A communication from abroad by WILLIAM EDGAR PRALL, of No. 906, 16th Street,
Washington, District of Columbia, United States of America, Engineer.
1, WILLIAM PHILLIPS THOMPSON F.C.S. M.I.M.E. of the Agency for
Foreign Patent Solicitors, 6 Lord Street Liverpool, and 6 Bank Street
Manchester both in the County of Lancaster, and 323 High Holborn in the
County of Middlesex, Civil Engineer do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
The object of this invention is to utilise heat stored in a fluid such as water in a
manner and by an apparatus suitable for propelling vehicles like street cars without
the necessity of transporting a heating apparatus or tanks of great size such as
required when compressed air is solely or mainly relied upon for motive power;
and the invention consists in the matters hereinafter described and particularly
pointed out.
In the accompanying drawing, the figure is a broken elevation, partly in
section, of a car with an apparatus for carrying out the improvement applied
thereto.
In said drawing, the numeral 1. indicates an air engine, and 2, tanks for com-
pressed air, which may be of any convenient form and number. 3 indicates a pipe
through which these tanks can be charged either from a main, or holder or com-
presser, as desired. The tanks communicate with each other and with pipes 3 and 9
through branches 4. 5 indicates a tank for hot water, and 6 a charging inlet.
7,7 indicate cocks in the charging inlets, and 8, 8 cocks in pipes leading respectively
from the tanks 2 and 5 to a common pipe or conduit 9, leading to the valve
chest of the engine. 10 is a cock in said pipe 9, which, in the present instance,
is shown as provided with a crank 11, connected by a rod 12 and a chain 13
with a brake rod 14. A spring 15 is adapted to open cock 10 when the brake rod
is reversed.
The operation of the invention is as follows:-
The tanks 2 having been charged in any desirable manner with air under a high
pressure, and the tank 5 with water. heated preferably to the temperature of
superheated steam, or to about 400 degrees Fahrenheit, the cocks 8 are opened to
permit the flow of both air and water into the conduit 9, which leads to the valve
chest of the engine, and upon opening the cock 10 the air and water together enter
the cylinder through the valve chest and are at once expanded therein and drive
the engine and (in the present case) propel the car, as will be understood without
particular description. The heat of the water will be imparted to the air and will
increase its tension and efficiency, and overcome also the tendency of expanding air
to "freeze" the engine, while reciprocally the expansion of the air will cool and
condense the steam or vapour. Obviously the original adjustment of the sizes of
tanks and the degree of air pressure and temperature of water and the subsequent.
regulation of the cocks 8 can be such that the temperature of the water of con-
densation will not be above or much above the normal, though the invention is not
limited to such a feature, nor is the invention limited to the particular details of
construction set forth. It is obvious, for example, that the air and water might be
conveyed to the engine through separate conduits having suitably controlled cocks.
Nor is it essential that the air and water be admitted simultaneously to the engine,

page_text: nor that any definite amount of water he used, the hot water being most essential,
and suitable provision for exhausting it of importance, and some latitude in details
may be exercised without departure from the invention. The improvement is
primarily intended for running engines on street cars, but can be employed in
moving vehicles of any kind, and for like purposes where it is desired to use hot
water as a source of power to avoid the presence of a fire and also of extensive
tanks.
If the temperature of the water be as high or approximately as high as above
recommended, or about 400 degrees Fahrenheit, it must, of course, be kept confined
and under pressure to prevent the generation of steam. Under some circumstances,
it may happen that the pressure in the water tank will at times exceed that in the
air tank. To provide for equalising the pressure in the tanks, they are connected
by a pipe, as 19, having a check valve. 18 opening towards the water tank.
A pipe 17, connecting the top of the water tank and the conduit 9, and
provided also with a cock, may be used under some circumstances for taking
steam or water from the tank to the engine with or without admission of com-
pressed air.
The pipe 19 may be opened to admit compressed air to maintain pressure in the
water tank after a portion of the water has been drawn off and the generation of
steam may thus be hindered. The pipe 17 can be used to convey air so used in the
tank to the engine, water being simultaneously forced through pipe 8. Under
some circumstances, the pressure in the tank 5 may be permited to fall so low that
steam can be taken from its upper part to run the engine. But, though this is
within the capacity of the apparatus, it is not a principal intent of it, but, on the
contrary, as it is characteristic of the main improvement that hot water in con-
siderable volume is introduced into the engine cylinder.
In the improved combination, there is used a cylinder provided with a valve
chest 16 upon its under side to suitably exhaust water. This is introduced into the
cylinder by this method in such quantity that it cannot be successfully removed
therefrom except by a special construction or arrangement, such as a valve chest
arranged on the under side of the cylinder. Its quantity and its state of agitation
in the cylinder and the action of the air thereupon would hinder its escape through
ordinary outlets or cocks. The construction must be such that water can be driven
out, or otherwise it will produce a pounding in the cylinder and other more
disastrous results. According to the arrangement herein described and illustrated,
water will fall by gravity to the exhaust port and be forced out in larger quantity
than would otherwise be possible. It can be exhausted into a holder carried on
the car, and re-used, if desired, or, in some cases, it can be discharged upon the
track.
As already indicated, the present method obviates the necessity of extensive or
numerous tanks for air storage. It also completely provides for utilising the heat
of water, it being practicable to regulate the relative amount of air and water so
that the latter shall be discharged at a low temperature. The amount of heat
imparted to the air by the water can be regulated and made uniform, which cannot
be effected in an apparatus wherein the air is carried through the water. And
further, the amount of water supplied to the tank and used in a given time or on a
certain trip or number of trips can be so regulated that it will be empty when it
comes to rest, thus avoiding the great loss incident to the cooling down of a large
body of hot water as is the case in the boilers of steam engines, when their work
for the time is completed.
It is not, however, the primary object of the improvement to economise heat, but
to provide for propelling vehicles by means that neither overload them nor
necessitate the carrying of fire, and, for this object, heat is employed derived from
water, to obviate the use of air tanks of great extent, and this effect requires a
combination wherein such water can be freely discharged from the cylinder of the
engine.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1. The improvement in the art of operating an engine to propel cars or like
vehicles, which consists in storing an air tank to be carried in the car with com-
pressed air; in storing a water tank with highly heated water under pressure ;
conveying such air and water to an engine cylinder on the car and introducing
them into the same; permitting the water to heat the air; and the air to expand
in the cylinder, thereby driving the engine and cooling the fluids, and then
exhausting the air and water from the cylinder, substantially as set forth.
2. The combination of a tank of compressed air; a tank of highly heated water
under pressure, said tanks being located on and adapted to be carried with a car or
other vehicle, and being disconnected from a heating and compressing apparatus;
an engine having a cylinder provided with an exhaust port in its bottom; a pipe or
pipes leading from the tanks to the engine cylinder; all as specified, whereby air
and water can be supplied to the cylinder, and air and water can be subsequently
exhausted, substantially as set forth.
3. The combination of a tank of compressed air; a tank of highly heated water
under pressure; an engine having a cylinder provided with an exhaust port in its
bottom a pipe or pipes leading from the tanks to the engine cylinder; whereby
air and water can be supplied to the cylinder, and air and water be subsequently
exhausted and a pipe leading from the air tank to the upper part of the water
tank to maintain pressure therein, substantially as set forth.
4. The combination of the air and water tanks, and pipes leading therefrom to
the engine cylinder; the water pipes communicating with the lower part of the.
water tank a pipe leading from the air tank to the upper part of the water
tank to maintain pressure therein; and a pipe leading from the upper part of
the water tank to the cylinder to convey air and steam, substantially as set
forth.
5. The combination of the air and water tank; and pipes leading therefrom to
the engine cylinder; the water pipe communicating with the lower part of the
water tank; a pipe leading from the air tank to the upper part of the water tank
to maintain pressure therein; and a pipe leading from the upper part of the water
tank to the cylinder to convey air or steam, said cylinder having an exhaust port
in its bottom, substantially as set forth.
6. The combination of a tank stored with highly heated water under pressure
with an engine having a cylinder provided with an exhaust port in its bottom, said
tank being located on and adapted to be carried with a car or other vehicle, and
disconnected from a heating furnace, substantially as set forth.
Dated this 21st day of March 1891
WM. P. THOMPSON & Co.,
Agents for the Applicant.