Invention relating to the Use of Liquefied Air to Produce Com- pressed Air for Driving Engines on Motor Cars, Tram Cars, or other Locomotives.
Year: 1898

page_text: Invention relating to the Use of Liquefied Air to Produce Com-
pressed Air for Driving Engines on Motor Cars, Tram Cars, or
other Locomotives.
I, EDGAR CHARLES THRUPP, Civil Engineer, of Southdene, Ashley Park Road,
Walton on Thames, Surrey, do hereby declare the nature of this invention
to be as follows;
In accordance with my invention, air is liquefied by suitable stationary
machinery and apparatus, and the liquid is placed in strong metal receivers
capable of withstanding high internal pressure, and surrounded by non-conduct-
ing jackets or coverings and provided with safety valves. These receivers are
carried on the motor cars, locomotives or tram cars to be propelled, and con-
nected by pipes to suitable evaporating coils or boilers and super-heating coils
to which heat is applied and the liquid air is transformed into hot compressed
air which is employed to drive the propelling engines. I prefer to use com-
pound engines provided with intermediate receivers in which the air can be
re-heated before passing to the low pressure cylinders, and also with suitable
valves for converting them to simple engines using high pressure air in both
cylinders for starting and running up steep gradients.
The engines are made reversible, and may either drive on to the axles of the
locomotives direct or on to counter shafts with suitable gear connecting to
the axles.
Part of the heat required for evaporating and expanding the liquid air may
be derived from the atmosphere by passing the air through coils or pipes exposed
to the open air. These pipes are liable to become covered with snow and ice
formed by the condensation of moisture from the atmosphere, and I therefore
arrange them in duplicate so that the cold air may be shut off from either section
periodically to allow the snow and ice to melt off the outside of the pipes. In
addition to the heat derived from the atmosphere, I provide for heating the
liquid air or compressed gaseous air, or both, by burning fuel and passing the
products of combustion over the air pipes of the super-heating, re-heating and
evaporating coils in the opposite direction to that in which the compressed air
is travelling to the engine, so that the products of combustion are ultimately
reduced to a temperature below that of the atmosphere under ordinary working
conditions and then discharged.
For street and road traffic I prefer to use oil or gas as fuel and I regulate the
production of the hot compressed air by manipulating a cock on the fuel supply
pipe to the burner or furnace as well as by a cock on the liquid air supply pipe
to the boiler. The liquid air reservoir is preferably placed at a higher level
than the boiler or evaporating coils, to enable the liquid to gravitate to the
latter. A second pipe connects the top of the reservoir with the upper part
of the boiler to allow free communication of gaseous air between the two.

page_text: Coal or coke may also be used as fuel and is more suitable for locomotives
on railways, country motor vehicles for goods traffic and the like.
Dated this 23rd day of December 1898.
Invention relating to the Use of Liquefied Air to Produce Com-
pressed Air for Driving Engines on Motor Cars, Tram Cars, or
other Locomotives.
I, EDGAR CHARLES THRUPP, of Southdene, Ashley Park Road, Walton on
Thames, Surrey, 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:-
In accordance with my invention, air is liquefied by suitable stationary
machinery and apparatus and the liquid is placed in strong metal receivers
capable of withstanding high internal pressure and surrounded by non-conduct-
ing jackets or coverings and provided with safety valves. These receivers are
carried on the motor cars, locomotives or tram cars to be propelled, and con-
nected by pipes to suitable evaporating coils or boilers and super-heating coils
to which heat is applied, and the liquid air is transformed into hot compressed
air which is employed to drive the propelling engines. I prefer to use com-
pound engines provided with intermediate receivers in which the air can be
re-heated before passing to the low pressure cylinders, and also with suitable
valves for converting them to simple engines using high pressure air in both
cylinders for starting and running up steep gradients.
The engines are made reversible, and may either drive on to the axles of the
locomotives direct or on to a counter shaft with suitable gear connecting to
the axles.
Part of the heat required for evaporating and expanding the liquid air may
be derived from the atmosphere by passing the air through coils or pipes exposed
to the open air. These pipes are liable to become covered with snow and ice
formed by the condensation of moisture from the atmosphere and I therefore
arrange them in duplicate so that the cold air may be shut off from either section
periodically to allow the snow and ice to melt off the outside of the pipes. In
addition to the heat derived from the atmosphere I provide for heating the
liquid air or compressed gascous air, or both, by burning fuel and passing the
products of combustion over the air pipes of the super-heating, re-heating and
evaporating coils in the opposite direction to that in which the compressed air
is travelling to the engine so that the products of combustion are ultimately
reduced to a temperature below that of the atmosphere, under ordinary working
conditions and then discharged.
For street or road traffic I prefer to use oil or gas as fuel and I regulate the
production of the hot compressed air by manipulating a cock on the fuel supply
pipe to the burner or furnace as well as by a cock on the liquid air supply pipe
to boiler. The liquid air reservoir is preferably placed at a higher level
than the boiler or evaporating coils, to enable the liquid to gravitate to the
latter. A second pipe connects the top of the reservoir with the upper part
of the boiler to allow free communication of gaseous air between the two.
Coal or coke may also be used as fuel and is more suitable for locomotives
on railways, country motor vehicles for goods traffic and the like.

page_text: The arrangement of the various parts of the apparatus are shown diagram-
matically on the accompanying drawing. A is the strong metal receiver con-
taining the store of liquid air, which is poured in through the inlet valve B
whilst the blow off cock C is open to the atmosphere. Both B and C are closed
whilst the liquid air is being used. The receiver A is surrounded by the non
conducting casing D leaving a small annular space E in between. A safety
valve F is fitted on the pipe G communicating with the receiver A, and any
exhaust from the safety valve is discharged through the pipe f f into the lower
part of the space E in which it passes upwards and escapes by an opening H
at the top. The air escaping by the safety valve is thus used to cool the casing D
and thereby diminishes the passage of heat into the receiver A and checks the
evaporation of liquid air which occurs in consequence of such passage of heat.
The liquid air is drawn off for use through the valve I which is used to regu-
late the amount passed into the evaporating coils or boilers J, J. which are
exposed to the atmosphere and can be utilised alternately by manipulating the
two way valve K.
On leaving the coils J, J, (or either of them) the air passes upwards through
another set of coils or heaters L, L, which may also be arranged to work alter-
nately if desired, and thence downwards through a third set of coils M, and is
heated by the products of combustion of the fuel burnt in the chamber N. The
coils L L and M are enclosed in casings 00 (after the manner of water tube
boilers) which serve to direct the passage of the products of combustion as indi-
cated by arrows in the drawing. The pipe G connects the top of the heating
coils to the top of the receiver A, to permit any air that may be evaporated in
the latter whilst the engine is running, to pass over and assist in driving the
engine.
The air on reaching the lower end of the coil M is raised to a temperature
considerably above that of the atmosphere, whilst the products of combustion
on reaching the lower end of the coils L L are reduced below the temperature
of the atmosphere and are then exhausted at P. The passage of air from the
coil M to the engine is regulated by the valve Q.
R is the high pressure cylinder of the engine and S is the low pressure
cylinder.
In ordinary working the exhaust air from the high pressure cylinder passes
through the valve T to the intermediate heating coil or receiver U, which is
enclosed in the casing 0, or in a similar casing, and heated by the products of
combustion of fuel. The air then passes to the low pressure cylinder S and is
exhausted to the atmosphere at V. The exhaust may be arranged to blow over
the coils J, J, either simultaneously or alternately to assist in evaporating the
liquid air, or it may be discharged into the annular space E surrounding the
chamber A to cause the liquid air to evaporate in A whilst the engine is run-
ning. The final discharge of the air exhausted from the engine may be mixed
with the products of combustion exhausted from P, in order to ensure the entire
immunity from unpleasant hot waste gases.
The valve T is shown diagrammatically on the drawing as a slide valve, but
it may be any mechanical equivalent of a slide valve, and may be worked by
a hand lever, or by a hand wheel and screw or other suitable well known device.
As shown on the drawing the valve T is set for working the engine compound,
but when the slide is moved to the other end of the stroke the exhaust from
the cylinder R passes away to the pipe V and a supply of high pressure air
from the valve Q is admitted to the coil U and thence passes to the cylinder S.
This arrangement is intended to facilitate starting or working up steep gradients.
The combustion chamber N may be a coke or coal furnace of ordinary con-
struction or it may be a combustion chamber for oil or compressed gas fuel
drawn from the reservoir W through the valve X by which the rate of combus-
tion may be regulated.
The evaporators or heaters are indicated on the drawing as spiral coils, but

page_text: they may be constructed in a similar manner to any suitable form of steam boiler,
superheater or condenser.
The relative situations of the parts on the locomotive or tram car, or motor
car, are obviously capable of being modified to suit various designs and purposes,
but the drawing and arrangement herein described indicate the essential features
of my invention.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what
I claim is
1) In motor cars, tram cars or other locomotives driven by compressed air
derived from a store of liquid air, the arrangement of a jacketed reservoir for
the liquid air in combination with evaporating coils or boilers and superheaters
in which the liquid air is transformed into hot compressed air and utilised to
drive the engines substantially as described in the foregoing specification and
illustrated in the drawing.
2) In apparatus for converting liquid air into hot compressed air for driving
locomotive or other engines, the arrangement of coils or boilers and super-heaters
in duplicate to provide for shutting off either set periodically to melt off the
snow and ice which may be deposited on the pipes, substantially as herein before
described.
D
2
T
1
1000