Improvements in Means for Propelling and Heating Street-cars and other Tramway Vehicles.
Year: 1888

page_text: Date of Application (in United Kingdom), 15th Oct., 1883
Complete Specification Left, 15th Oct., 1888
Complete Specification Accepted, 30th Nov., 1888
COMPLETE SPECIFICATION.
Improvements in Means for Propelling and Heating Street-cars and
other Tramway Vehicles.
1, WILLIAM EDGAR PRALL, of the Hotel Arno, in the City of Washington, District
of Columbia, United States of America, Engineer, do hereby declare the nature of
my invention for "IMPROVEMENTS IN MEANS FOR PROPELLING AND HEATING STREET-
same is to be
CARS AND OTHER TRAMWAY VEHICLES" and in what manner
performed, to be particularly described and ascertained in and by the following
statement -
a
My invention is an improvement in means for propelling and heating street-
cars and other similar vehicles in which superheated water, superheated oil, and
steam, or their equivalents, are employed as power and heat producing mediums,
and in which superheated water and superheated oil, or their equivalents, are
employed as ineans of storing heat and generating steam or other expansive
vapors to propel the engine and heat the car without combustion; and the invention
consists in the construction, combination, and arrangement of parts disclosed in the
following specification, of which the accompanying drawings form a part, and in
which similar letters of reference indicate the same or equivalent parts throughout
the several views.
Figure 1, is a view showing in elevation a car provided with my improved
apparatus. Fig. 2, represents a detail. Figs. 3, 4, 6, 7, 8, 10, 11, and 13, represent
details in construction and modifications of the superheated oil tank. Fig. 5, is an
enlarged end plan view of the water and oil tanks, together with the pipes connecting
the same and certain details relating thereto. Fig. 9, is a modified arrangement of
the oil and water tanks and their connections. Fig. 12 shows one mode of applying

page_text: the non-beat-conducting material to the oil tanks and the evaporating tubes
surrounding the same. Fig. 14, is a plan of a modified arrangement of the apparatus
shown in Fig. 1, and Fig. 15, is a detail showing a form of valve used in the pipes
which connect the water and oil tanks.
In applying my apparatus to a car I adopt the general plan shown in Fig. 1. The
storage or superheated water and oil tanks, together with the engine and other
operative mechanism, being placed beneath the car.
A, represents the storage or oil tank, placed between the wheels of the car; B, the
superheated water tank, and C, the engine.
The tank A, may be made of any desired material and of any preferred form. It
is provided with pipes A', and A, by which the oil or other heat storage material
may be introduced and discharged. The tank is also surrounded by small closely
connected copper tubes b, said tubes being in communication with chamber &², in such
manner as to permit of a free communication between said chambers and tubes,
whereby a large evaporating and expanding surface is obtained without the friction
consequent to one long continuous pipe and freedom from the trouble consequent upon
the expansion and contraction of such a pipe, together with ease of access to the tubes
in case they should at any time require cleaning. This may be done by simply
removing the flange B³, which is attached to and covers the chamber 62, as shown in
Figs. 1, 3, 4, and 6. The tubes b, may be applied to the tank A, by having the
chamber 6, with which they communicate, constructed of a -shape similar to that of
the tank, and when said chamber is placed at each end of the tank, as shown in Fig. 4,
the pipes will rest upon the outer surface thereof. I also contemplate the employment
of a coil, 63, within the oil tank, placed directly in contact with the hydrocarbon or
heat storage material, whereby heat will be transmitted from the storage material to
the coil by direct contact, while in the case of the tubes, the tubes receive their heat
by radiation from the walls of the tank containing the heat storage material, by which
the radiated heat, which would otherwise be lost, will be taken up and utilized, and the
covering which surrounds the tubes, prevents the radiation therefrom.
In Fig. 7, is shown a form of construction in which the oil tank is surrounded by a
continuous chamber, &, which takes the place of the tubes b, shown in the other views,
the said chamber being separated from the tank by an air space.
In Fig. 9, the tubes b, are represented by enlarged tubes placed at the junction of a
series of oil tanks, said tubes being provided with branch connections D, which com-
municate with a common supply and exhaust, D', the oil tanks being provided with
branch connections E, communicating with a common supply and exhaust, E.
In Figs. 10, and 11, I have shown a mode of constructing the tube b, in sections
of pipe screwed together, having a common supply and exhaust, D¹.
Fig. 8, shows a plan of construction similar to that of Figs. 1, 3, and 4, with this
difference, that the chamber 62, in the place of encircling the oil tank is made to extend
so that the top and bottom only of the tank will be covered by pipes b, said chamber
being connected at each end by pipes S. Fig. 13, is a modification of the oil tank
and its attachments in this respect. In addition to covering the top and bottom
of the tank with said tubes, as in Fig. 8, it is proposed to surround all the sides.
of the tank with evaporating tubes. This is accomplished by surrounding all the
sides of the tank with the evaporating tubes; said tubes on four sides terminating
in the chamber ², and being brought in communication with the top and bottom
sections by tubes S. By this construction I have surrounded the entire storage or
oil tank with the evaporating and expanding tubes and have established a communi-
cation throughout all the tubes and chambers in a manner to establish perfect
circulation, and thereby preventing loss of heat by radiation from the storage tank,
as the radiation from all sides will be taken up by said evaporating and expanding
tubes and chamber, the tubes, of course, being covered, so as to prevent as much as
possible radiation therefrom.
Having fully described the heat storage tank and its connected expanding and
evaporating chambers and tubes in the various modifications shown, I will now
proceed to describe the construction of the tank B, which may be charged with

page_text: superheated, water, liquid ammonia, ether, alcohol, carbonic-acid gas, or any
other evaporating substance that.may be employed, superheated water. being preferable
to all others.
The tank B, is constructed of metal and of suitable strength to stand any desired
pressure, and may be placed in any desired position, preferably under the body of the
car and as close as possible to the storage tank, and is to be provided with non-heat-
conducting covering to prevent radiation therefrom. This tank will also be provided
with supply and discharge pipes B', and B³, by which it is charged and made ready
for operation. It is further provided with pipes c, and c³, connecting said tank at the
top and bottom with a three-way valve, H. [Shown in Fig. 15.] A pipe h, provided.
with a pressure reducing valve A', connects the valve H, with another three-way
valve H, and pipes 2, and h³, connect valve H', with the evaporating and expanding
chamber and tubes connected with the heat storage tank. Tank B, is also provided
with a back-pressure pipe F, extending to and communicating with the evaporating
chamber, connected with the heat storage tank. This pipe is provided with a check-
valve F. [Shown more fully in Fig. 5.] A steam pipe K, connects the evaporating
chamber with the steam chamber C, of the engine, and a valve, K1, is placed. in said
pipe near its junction with the evaporating chamber. A lever L. is provided with a
rod L, which, connects the lever I, with the three-way valve H', and also with
valve K, in the steam pipe. M, is a lever connected by rod M', with the three-way
valve H, and O, is a chain belt extending from a gearing 01, on the car axle to
gearing 0, on the crank shafts, with which the engine is connected.
An exhaust pipe P, leads from the engine and communicates with the condenser P1,
which may be placed on the top of the car, either by direct line through pipe P*, or
through pipes P³, placed under the seats of the car. The direction of the exhaust
steam will be controlled by valves R. by which it may be directed either through
the interior of the car, to heat the same in cold weather, or directly into the
condenser.
I
The condenser for use where superheated water is employed is a simple affair and
may be constructed of light tubes surrounded by a light shell, forming a space around
the tubes, into which space the steam is allowed to exhaust, the ends of the tubes
communicating with the atmosphere at each end, so as to permit a free circulation of
air through the same. Where it is desirable to save the condense-water, it may
be conducted by means of a pipe R', to a receiving tank R2, placed underneath
the car.
I have also shown in Fig. 12, one mode of covering the evaporating tubes on the
outer side with some well known non-conductor, by which radiation from the outer
sides of said tubes is prevented, while the lower half of the tubes is left free to absorb
the radiated heat from the heat storage tank, which they surround, and in Fig. 14 I
have shown an enlarged view of the tanks and the pipes connecting the same,
together with the levers and rods for controlling the valves with which the pipes are
provided. In this view but two sides of the storage tank are provided with evapo-
rating tubes, and they are connected by means of pipes S, as in Fig. 8, and in this
figure pipe 6, is shown terminating in the evaporating chamber or tube at the bottom,
so as to cause the water to not only pass through the pipe placed within the storage
tank, but to be discharged, so as to pass through the outer layer or series of
evaporating tubes before it passes to the engine.
In the operation of this apparatus the tanks B, and A, are filled at stations provided
for the purpose, the tank B, with superheated water or any other liquid that will serve
the purpose, and tank A, with highly heated oil or any other substance in which a high
degree of heat may be stored without too great pressure. The manipulation of the
valves K, and H', by means of lever L, will establish a communication between
tank B. and the evaporating chamber or tubes around or through tank A. If lever M,
be operated so as to open communication between the lower part of tank B, and the
evaporating tubes, the superheated water will flow through the pressure reducing valve
into the evaporating chamber or tube. The pressure reducing valve ¹, is so regulated
as.to establish any required degree of pressure in the evaporating chamber and tubes, .

page_text: .
and to automatically regulate and maintain such pressure so long as the valves H.
and K, are open. The superheated water, after passing the valve ¹, and entering the
steam chamber 6, and the tube b, is immediately converted into steam by means of its
own specific heat and the radiated heat from the heat storage tank. The steam in
passing through the many evaporating and expanding tubes becomes superheated and
expanded to a high degree. The valve K', being open, this superheated steam passes
directly to the engine by which the car is propelled. If great power is required, or
when the heat in the storage tank has been reduced in temperature, by the proper
manipulation of lever L, the superheated water or steam may be admitted into the
coil 3, within the heat storage tank before entering the evaporating tubes around said
tank, thereby increasing the rapidity of the evaporation and the expansion of the steam.
If on the return trip it is found the temperature of the storage tank is not sufficient
to evaporate superheated water into superheated steam as fast as required, by the
movement of lever M, the water may he cut off from tank B, and saturated steain
created by tlie specific heat of the water in tank B, may be thrown into the expanding
chamber, and thereby converted into superheated steam and utilized with great economy
and force.
!
To stop the car, a single movement of the lever L, in the opposite direction from
tliat required to start the car is all that is required, as thereby valves H, and K', will
be closed and steam will be prevented from entering the engine and superheated water
or steam from entering the converting chamber from tank B. Should, however, there
be some water still remaining in the evaporating chamber and tubes, in order to
provide against excessive pressure or waste of heat by blowing off, the pipe F, and
valve F, are connected with the bottom of said chamber and tank B, and as soon as
the pressure in said chamber and tubes exceeds the pressure in tank B, any water left
in said chamber and tubes will be driven back and through valve F, into tank B.
.
It will be seen that by this simple and powerful apparatus, in which there is no
possibility of overpressure, there being no generation of heat, and without any
skilled engineer or fireman, and without any of the annoyance of dust, smoke, and
smells consequent to the combustion of fuel for power purposes, a simple, safe, and
economical apparatus for propelling and heating street-cars or other similar vehicles
is produced..
In the following claims the words "superheated water? are used to indicate
either hot water or any other fluid capable of being heated and converted into
steam or vapor, and the words "heat-storage tank" to indicate tank A, charged
with any material capable of being heated to a high degree without producing com-
bustion on too great pressure.
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 1
claim is:
1. In an apparatus for propelling street-cars, the combination of a superheated water
tank, a heat-storage tank provided with evaporating and expanding tubes surrounding
the same, and said pipes provided with valves connecting the superheated water tank
with said tubes, substantially as shown and described.
2. The combination, with a superheated water tank, a heat-storage tank provided
with evaporating tubes surrounding the same, and an evaporating tube or coil
within the same, of pipes provided with controlling cocks or valves forming com-
munication between the superheated water tank and the said tubes, substantially as
shown and described.
3. The combination of the superheated water tanks, the heat-storage tank, the
evaporating tubes, the pipes connecting the superheated water tank and the evaporating
tubes, and the back pressure pipe provided with the back acting valve F1, substantially
as shown and described.
'
4. The combination of the superheated water tank and the heat-storage tank provided
with evaporating tubes, said tanks being connected by means of pipes communicating
with the upper and lower portion of the water tank, said pipes being controlled by a

page_text: valve or valves in such a manner as to cause the flow of either superheated water from
the bottom or saturated steam from the top of the superheated water tank into the
evaporating tubes.
5. The combination of the superheated water tank and the heat storage tank pro-
vided with evaporating tubes, pipes connecting the water tank with the evaporating
tubes, pipes connecting the evaporating tubes with the engine, and valves controlling
said pipes operated by one common lever in such a manner as to admit water or steam
to the evaporating tubes at the same time that steam is admitted from the tubes to the
engine, and to shut off the supply of water or steam to the evaporating tubes
simultaneously with cutting off the supply of steam to the engine.
6: The combination, with the superheated water tank, the heat-storage tank provided
with the evaporating tubes within and around the same, and pipes connecting the
water-tank with the evaporating tubes, of a three-way valve placed in said pipes, so
arranged that the water or steam from the superheated water tank may be admitted
either through the evaporating pipe within the storage tank or be shut off therefrom and
caused to enter the evaporating tubes around the storage tank, substantially as shown
and described.
7. The combination of the superheated water tank, the heat-storage tank provided
with evaporating tubes, the pipes connecting the water tank with the evaporating tubes,
the engine, and a condenser connected with the exhaust of the engine, substantially as
shown and described.
8. The combination of the superheated water tank, the storage-tank provided with
the evaporating tubes, pipes connecting the water tank with the evaporating tubes, the
engine, the condenser, the radiating pipes or coils within the car, and pipes connecting
the condenser, the radiating coils, and the exhaust of the engine, substantially as shown
and described.
9. A heat storage tank provided with evaporating tubes on the outside thereof, said
tubes being covered with non-heat-conducting material, substantially as shown and
described.
10. A heat storage tank provided with evaporating tubes within and outside of the
same and non-heat-conducting material over the outer tubes, substantially as shown
and described.
11. A heat storage tank provided with an evaporating chamber b², evaporating
tubes b, and non-heat-conducting material on the outside of said tubes, substantially as
shown and described.
12. A heat storage tank provided with an evaporating chamber ², and evaporating
tubes b, and 63, substantially as shown and described.
13. The combination of the tank B, the tank A, provided with the evaporating
tubes, the pipes connecting tank B, with said tubes, the three-way valves H, and H
and the steam valves K, the said valves H, and K', being operated together, and
the pressure reducing valve ', substantially as shown and described.
14. The combination of the tanks B, and A, the tank A, being provided with
evaporating tubes, the pipes c, and c¹, connecting the tank B, with said tubes,
provided with valves H, H', and ', and the pipe F, provided with valve F¹, sub-
stantially as shown and described.
Dated this 25th day of September A.D. 1888.
In testimony whereof, I affix my signature in presence of two witnesses.
Witnesses:
WM. W. CANFIELD.
JOHN M. DELANEY.
WILLIAM E. PRALL.