Improvements in Engines or Motors Worked by Heated Air and other Gas.
Year: 1889

page_text: Date of Application, 28th Sept., 1889
Complete Specification Left, 28th June, 1890-Accepted, 13th Sept., 1890
PROVISIONAL SPECIFICATION.
Improvements in Engines or Motors Worked by Heated Air and
other Gas.
I, WYNDHAM BYRT PURLEWENT SPURWAY, of 37 Gay Street Bath, in the County
of Somerset, Engineer do hereby declare the nature of this invention to be as
follows:-
My invention relates to air engines and is designed to improve the construction of
the same.
An important feature in my said invention consists in utilizing air, which has been
previously compressed and heated in a suitable chamber, expansively from a high to a
low pressure cylinder.
My said invention comprises moreover various other improvements hereinafter set
forth.
In carrying my said invention into practice I provide a suitable frame or bed
supporting a high pressure and a low pressure cylinder placed side by side and pro-
vided with pistons and piston rods coupled by means of connecting rods to a suitable
crank shaft carrying a fly-wheel. The said cylinders are provided moreover with
suitable slide valves worked by means of excentrics upon the crank shaft, and are
substantially similar in construction to an ordinary compound steam engine. The
piston rods of the said cylinders are extended through the rear covers of the latter and
are coupled to the piston rods of air pumps or air compressors situated in the rear of,
and in line with the said cylinders. The air pump or air compressor in the rear of
the high pressure cylinder is preferably of smaller dimensions than that in the rear
of the low pressure cylinder. The air pump or air compressor in the rear of the low
pressure cylinder is arranged to draw air from the atmosphere, and is preferably pro-
vided for that purpose with circular valves in the cylinder covers. The said air pump
or air compressor delivers the said air into a small intermediate receiver from which it
is removed by the second or smaller air pump or air compressor and delivered to a
receiver or receivers of a cylindrical or other suitable shape placed in the interior of
the frame or bed supporting the above mentioned high and low pressure cylinders and
air pumps or air compressors. These cylindrical air receivers communicate by means
of a suitable pipe or pipes with a chamber also situated in the interior of the frame or
bed, and of such form and dimensions as the available space in the said frame or.bed
will admit of. One or more stop valves or stop-cocks are morcover provided for cutting
off the communication between the said cylindrical receivers and the said chamber
when desired. In the interior of this latter chamber are provided a number of gas
burners of any suitable description the supply of gas to which is delivered under
pressure from a cylindrical or other suitably shaped receiver (also placed in the
interior of the said frame or bed) by means of a pipe or pipes provided with a stop
cock or valve, or stop cocks or valves. To compress the gas in the said gas receiver
I provide a double acting pump of any well known construction connected by means
of suitable pipes with any available source of gas supply and with the said gas receiver.
The piston rod of the said pump is coupled to the slide valve of the high pressure
cylinder and is reciprocated thereby during the to and fro movement of the said slide
valve. An electric lighter or any other convenient means may be employed for lighting
the gas burners in the interior of the said heating chamber.
The engine will when started after a few revolutions begin, through the above
mentioned air pumps or air compressors, to compress the air in the cylindrical air
receiver or receivers and consequently also in the heating chamber when the commu-
nication between them is open, the said air becoming in a short time compressed in
the said air receivers and heating chamber to a high degree and a considerable

page_text: pressure being generated which will be increased by the high temperature imparted
to the said air by the heat generated by the flames from the said gas burners. The
compressed and heated air from the said heating chamber is delivered to the valve
chest or casing of the high pressure cylinder (by means of a suitable pipe,) from
which it is admitted alternately to either side of the piston by the action of the slide
valve, in the said valve chest or casing. From the said high pressure cylinder it is
admitted alternately by means of another slide valve to either side of the piston in the
low pressure cylinder, and is exhausted therefrom in a manner substantially similar to
that taking place in an ordinary compound steam engine or in any other suitable
manner into a chimney flue or elsewhere. A suitable intermediate receiver is
sometimes employed between the high and low pressure cylinder.
To regulate the speed of the engine when running I provide suitable mechanism for
altering or varying the throw of the slide valve admitting the compressed and heated
air to the high pressure cylinder, according to the speed of the said engine. That is
to say, I provide upon the stem or rod of the said valve a suitable quadrant having an
arc shaped slot in which is adapted to move freely a slide piece or block provided upon
the extremity of the rod of the excentric operating the said valve. This excentric rod
is so connected to an ordinary centrifugal governor of any suitable construction,
driven from the crank shaft of the engine, that when the speed of the latter increases
beyond the normal speed at which it is intended to run, and consequently the speed
of the said governor also increases in a corresponding ratio the said excentric rod
will be moved so as to shift the said slide piece or block in the said slotted quadrant
into such a position that the throw or travel of the slide valve will be decreased, and
consequently less compressed and heated air be admitted to the high pressure cylinder
from the heating chamber. Should on the contrary the speed of the engine be reduced
below the said normal speed the speed of the said governor will also be reduced in a
corresponding ratio, and the said excentric rod moved so as to shift the said slide piece
or block in the said slotted quadrant into such a position that the throw or travel of
the slide valve will be increased, and consequently more of the said compressed and
heated air admitted to the high pressure cylinder from the said heating chamber.
By connecting the piston rod of the herein before mentioned double acting pump
for compressing the gas employed in the burners in the heating chamber, to the slide
valve of the high pressure cylinder I provide for automatically adjusting the stroke of
the said pump to the throw or travel of the said slide valve; and thus regulating the
pressure of the said gas in accordance with the speed of the engine.
By employing two air pumps or air compressors and an intermediate receiver, for
compressing the air in the compressed air receiver or receivers, less power is expended,
and the compressing is more economically and evenly performed than would be the
case if only one air pump or air compressor was employed.
I prefer to make the said cylinders somewhat thicker than is usual in steam engine
cylinders of corresponding diameters so as to enable them to support the high
temperature, and pressure employed therein. By this means I am enabled to dispense
with the use of water jackets or other cooling devices, thus obviating the loss of heat
usually entailed when the latter are employed, and consequently economising the fuel
employed to heat the air, and increasing the efficiency of the engine.
When it is desired to stop the engine the supply of compressed air and gas is cut
off from the beating chamber by closing the stop cocks, or stop valves in the pipes
communicating between the latter and the compressed air receiver or receivers, and
gas receiver, the engine running down or stopping when the compressed air in the
heating chamber is consumed.
By employing the above mentioned cylindrical receiver or receivers for the com-
pressed air, and for the gas I am enabled when the engine is stopped in the above
described manner to maintain a supply of compressed air and gas for again starting
the said engine when required. The engine may be started for the first time, or when
no reserve of compressed air or gas has been kept in the said cylindrical compressed
air and gas receivers by giving the fly wheel a few turns by hand.
By placing the herein before mentioned cylindrical compressed air and gas receivers

page_text: and the heating chamber in the interior of the frame or bed of the engine I secure
compactness of design, and ensure the apparatus taking up as little space as possible.
The said compressed air and gas receivers and heating chamber, or either of them
may be however placed in any other convenient position.
Although I have hereinbefore described a convenient and advantageous method of
carrying my said invention into practice it is obvious that I can somewhat modify the
construction of my improved air engine without however in any way departing from
the nature of my said invention For instance instead of connecting the air pumps
or air compressors with the hereinbefore mentioned cylindrical compressed air
receiver or receivers, I can connect the said air pumps or air compressors direct with
the heating chamber, and in like manner I can dispense with the receiver for the
compressed gas, and connect the pump for compressing the said gas direct with
the supply pipe or pipes to the gas burners in the said heating chamber.
Instead of an ordinary D or other slide valve for admitting the said compressed
and heated air to the high pressure cylinder I sometimes employ a piston or other
convenient device.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Engines or Motors Worked by Heated Air and
.
other Gas.
I, WYNDHAM BYRT PURLEWENT SPURWAY, of 37 Gay Street, Bath, in the
County of Somerset, 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:—
My invention relates to engines or motors worked by heated air or other gas and
comprises various improvements hereinafter set forth.
•
An important feature of my said invention consists in improved means for
utilizing the expansion produced by heating compressed air in an enclosed chamber or
vessel for working a motor or engine.
Another important feature in my said invention is the provision of improved
means for heating the said air, and for using the said heated air effectively against a
piston in a cylinder.
My said invention comprises moreover an improved compound engine or motor
wherein the said compressed and heated air is used expansively from a high to a low
pressure cylinder, and various other improvements hereinafter set forth.
In the accompanying drawings I have shown how my said invention may be con-
veniently and advantageously carried into practice.
Figure 1 is a plan partly in horizontal section, and
Figure 2 is a side elevation partly in vertical section illustrating one form of my
improved engine motor or apparatus.
Like letters indicate corresponding parts throughout the drawings.
A is the bed plate or base plate of the engine, B is the cylinder, B is the slide valve
casing or air chest, B2 is the slide valve, B3 B3 are the ports for admitting the heated
air to the said cylinder B. B is the exhaust port for permitting the escape of the
said heated air, is the piston, D is the piston rod. The piston rod D is provided
with a cross head E, motion blocks F, and guide bars G and is coupled by means of
a connecting rod H to the crank 1 of a crank shaft I having a fly wheel J all
substantially similar in construction to those of an ordinary steam engine.
or
a is a a tank, receptacle, or receiver provided with a lining a of asbestos or other
material not liable to be injuriously affected by heat.
The said receptacle
receiver forms a support for the rear extremity or one extremity of the bed plate or
base plate A and serves for the reception of the compressed air. 6 is an air compressor

page_text: or air pump placed in line with the main cylinder B. The air pump or air com-
pressor is fitted with a piston c the piston rod d of which passes through the bottom
of the said cylinder B and is connected to the piston C, a suitable stuffing box and
gland B being provided for forming a tight joint. e é are valves one of which is
provided at each extremity of the cylinder b. The valves e open inwards and are
normally retained upon their seatings by means of springs which permit the said
valves to open under the pressure of the atmosphere. The said valves e serve for
admitting atmospheric air to the said air pump or air compressor. f, fare valves
opening outwards into a casing or chamber provided on the cylinder of the air
compressor or air pump. The said valves are normally retained upon their seatings
by means of springs and communicate with both extremities of the said
cylinder b. 2, are doors or covers for permitting of access to the said valves f. The
said casing or chamber is connected with the reservoir or receiver a by means of a
pipe g provided with a suitable stop cock or valve gl. h is a spherical or other suitably
shaped chamber preferably formed of steel. The chamber is connected with the
reservoir or receiver a by means of a pipe provided with a stop cock or valve i¹. jis
a small double acting pump of any well known construction. The said pump is
provided with a piston j the rod 2 of which passes through a suitable hole provided
in the side wall of the slide valve casing or air chest B' and is connected to the slide
valve B³, a suitable stuffing box or gland B being provided for forming a tight joint
round the said rod. is a supply pipe through which the pump is connected with
any available gas supply. is the delivery pipe which is provided with a stop cock
or valve . The delivery pipe passes into and up through the extremity of the
pipe which projects slightly into the said spherical or other chamber h and is
provided with holes or apertures thus forming a gas burner to which the gas is
supplied under pressure. The spherical or other chamber is connected by means of
a pipe to the valve casing or air chest B¹. The pipe is connected with the
reservoir or receiver a by means of a pipe provided with a stop cock or valve l'.
A portion of the compressed air passes through the pipe to the slide valve casing or
air chest B¹. The air thus admitted creates a suction and facilitates combustion
in the spherical or other chamber h. The said air mixes with the highly heated
air from the said spherical or other heating chamber h in the pipe k.
8
I provide, moreover in combination with my improved engine suitable means for
automatically regulating or adjusting the throw of the slide valve. For instance the
rcd or stem B7 of the slide valve B is coupled at B8 to the rod m of the strap ml of
an eccentric n' mounted on the crank shaft. I. The eccentric n. is arranged loosely
upon the said crank shaft and is firmly secured to or formed on an arm or lever o
pivoted at o¹ to a disc p keyed or otherwise firmly secured upon the crank shaft I.
y is an arm or lever pivoted at q¹ to the said disc. The long arm or one arm of the
said lever is provided with a weight 2, and the short arm or other arm thereof is
coupled at 93 to one extremity of a connecting rod r the other extremity of which is
coupled at to the free extremity of a spring s. The other extremity of the spring.
is firmly secured to the disc p or to a flange provided thereon. The said connecting
rod is connected at to the other or free extremity of the swinging arm or lever o.
The eccentric n will be thus retained normally in such a position on the crank shaft I
as to ensure its full throw and consequently the full stroke or travel of the slide
valve B2 and of the piston j of the gas pump j. If however the engine or motor
attain too high a velocity and the crank shaft be therefore rotated above a predeter-
mined speed the resistance of the spring s will be overcome and the weighted arm of
the lever y will be moved outward by centrifugal force, and the short arm or other
arm thereof consequently moved inward and through the connecting rod and swing-
ing lever o the eccentric will be moved or adjusted so as to shorten the throw thereof,
and consequently the stroke or travel of the said slide valve B2 and of the gas pump
piston. The amount of the said adjustment depends upon the velocity of the engine.
1 thus provide for regulating or governing the speed of the engine by automatically
altering the stroke or travel of the slide valve and consequently the admission of the
heated compressed air to the main cylinder B. The supply of gas to the heating

page_text: chamber is also regulated in accordance with the said speed, and the consequent
consumption of heated air by the said engine. is a pressure gauge connected by
means of a pipe t' with the reservoir or receiver g and by means of which the pressure
of air in the said reservoir or receiver can be ascertained.
I prefer to provide the pipes it and 7 with flange joints 12, 13, 1, and to connect the
pipe k to the spherical or other heating chamber by means of a flange joint & so
that the said spherical or other heating chamber can be readily disconnected or removed
for repairs or other purposes.
The gas jet in the spherical or other heating chamber h may be lighted by means of
electricity or in any other convenient manner. The flanged disc p may be used as an
ordinary pulley for communicating power by means of strap or belt gearing,
The operation of my improved motor or apparatus is as follows that is to say :-If
the air in the reservoir or receiver a stands at a very low pressure, the fly wheel is
turned round by hand until the said pressure is raised sufficiently high. The gas is
then turned on, the jet in the spherical or other heating chamber is lighted and the
stop valves or stop cocks and are opened so as to allow the said compressed air to
pass to the said spherical or other heating chamber where it is heated expanded, and
from which it passes to the slide valve casing or air chest B and is admitted alternately
to each side of the piston C by the action of the slide valve B2. The slide valve B2 is
preferably set to cut off early in the stroke so that the said compressed and heated air
is used expansively. The heated compressed air is permitted to pass from the said
cylinder B to the exhaust in the usual manner after having performed its work.
The engine or motor will after a few revolutions begin through the air pump or air
compressor to compress the air in the reservoir or receiver a and in the heating
chamber the said air becoming in a short time compressed to a high degree which
pressure is considerably increased by the high temperature imparted to the said air in
the raid heating chamber h.
When it is desired to stop the engine or motor the supply of compressed air and
gas is cut off from the heating chamber by closing the stop cocks or stop valves /¹¹
and the engine running down or stopping when the compressed and heated air in
the heating chamber is consumed.
By employing the reservoir or receiver a for the compressed air I am enabled when
the engine is stopped in the above described manner to maintain a supply of com-
pressed air and gas for again starting the said engine when required.
In some instances I provide a high pressure and a low pressure cylinder placed side
by side and provided with pistons and piston rods coupled by means of connecting
rods to a suitable crank shaft carrying a fly wheel, and having slide valves worked by
means of eccentrics upon the said crank shaft, substantially similar in construction to
an ordinary compound steam engine. Each of the said piston rods is arranged to
extend through the rear cover or cylinder bottom and is coupled to the piston rod of
an air pump or air compressor situated in the rear of, and in line with the said
cylinders. The air pump or air compressor in the rear of the high pressure cylinder
is preferably of smaller dimensions than that in the rear of the low pressure cylinder.
The air pump or air compressor in the rear of the low pressure cylinder is arranged to
draw air from the atmosphere, and to deliver the said air into a small intermediate
receiver. The second or smaller air pump or air compressor receives its air from the
said intermediate receiver and delivers it to a cylindrical or other suitably shaped
receiver or receivers which are preferably placed in the interior of the frame or bed of
the engine. The said cylindrical or other air receivers communicate by means of a
suitable pipe or pipes with a heating chamber also situated in the interior of the frame
or bed.
Suitable stop valves or stop cocks are provided for cutting off the communication
between the said cylindrical receivers and the said heating chamber when desired. In
the interior of the latter chamber I provide a number of gas burners of any suitable
description. The supply of gas to these burners is delivered under pressure from a
cylindrical or other receiver (also placed in the interior of the said frame or bed) by
means of a pipe fitted with a stop cock or valve. The piston rod of the pump for

page_text: compressing the gas in the said receiver is coupled to the slide valve of the high
pressure cylinder and is reciprocated thereby during the to and fro movement of the
said slide valve. An electric lighter or any other convenient means is employed for
lighting the said gas burners.
The compressed and heated air is delivered to the valve casing or air chest of the
high pressure cylinder from which it is admitted by the slide valve alternately to each
side of the piston. From the said high pressure cylinder it is admitted (with or with-
out an intermediate receiver) alternately by means of another slide valve to each side
of the piston of the low pressure cylinder and is exhausted therefrom in a manner
substantially similar to an ordinary compound steam engine.
To regulate the speed of the engine or motor when running I provide upon the
stem or rod of the high pressure slide valve a suitable quadrant having an arc shaped
slot in which is adapted to move freely a slide piece or block provided upon the
extremity of the eccentric rod operating the said valve. This eccentric rod is so con-
nected to an ordinary centrifugal governor of any suitable construction, driven from
the crank shaft of the engine, that when the velocity of the latter increases beyond
the normal or predetermined speed the said governor will act upon the eccentric rod
and shift the said slide piece or block in the said slotted quadrant into such a position
that the stroke or travel of the slide valve will be decreased; and consequently less
compressed and heated air be admitted to the high pressure cylinder. Should on the
contrary the speed of the engine be reduced below the said normal or predetermined
speed the said governor will act upon the said eccentric rod and shift the said slide
piece or block in the said slotted quadrant into such a position that the stroke or travel
of the slide valve will he increased, and consequently the high pressure cylinder
receive a larger supply of the said compressed and heated air.
By employing two air pumps or air compressors and an intermediate receiver, for
compressing the air in the compressed air receiver or receivers less power is expended,
and the compressing is more economically and evenly performed.
I prefer to construct the cylinder or cylinders and other parts of the apparatus
which are liable to become heated to a high degree by contact with the compressed
and heated air during work, of steel and to form the said cylinders somewhat thicker
than is usual in steam engine cylinders of corresponding diameters. The air pipes
are sometimes lagged or covered with any suitable non conducting material, and the
spherical or other heating chamber may be lined with asbestos, fire clay or other
suitable material.
By arranging the hereinbefore mentioned compressed air reservoir or receiver so as
to form a portion of the frame or support of the engine or motor I secure compact-
ness of design and ensure the apparatus taking up as little space as possible.
Although I have hereinbefore described convenient and advantageous methods of
carrying my said invention into practice it is obvious that I can somewhat modify
the construction of my improved engine or motor without in any way departing
from the nature of my said invention. For instance instead of connecting the air
pump or pumps with the herein before mentioned compressed air receiver I sometimes
connect the said air pump or pumps directly with the heating chamber.
Instead of an ordinary slide valve for admitting the said compressed and heated air
to the cylinder or cylinders I sometimes employ a piston valve or other convenient
device for this purpose.
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
First. An engine or motor wherein the effective power is produced by heating
compressed air in an enclosed chamber and admitting the said compressed and
heated air alternately to each side of a piston or pistons substantially as set forth.
Second. The improved means for compressing and heating the air comprising the
air pump or air compressor, the reservoir or receiver and the spherical or other
heating chamber substantially as described.

page_text: Third. The means for regulating the admission of the compressed and heated air
to the cylinder of the engine or motor by regulating or adjusting the stroke or travel
of the slide valve in accordance with the speed of the engine substantially as described,
with reference to Figure 2 of the accompanying drawings.
Fourth. The means for supplying gas under pressure to the burner or burners in
the said heating chamber and regulating the said supply of gas comprising a double
acting pump driven by the slide valve substantially as specified.
Fifth. The modification of my improved engine or motor comprising two cylinders
and air pumps or air compressors and an intermediate receiver or reservoir for the
air and for the gas substantially as described.
Sixth. The means for altering or regulating the stroke or travel of the slide valve
comprising the slide block or piece and the quadrant substantially as described.
Seventh. The improved engine or motor substantially as described with reference
to the accompanying drawings, and operating as and for the purposes hereinbefore
specified.
Dated this 28th day of June 1890.
WYNDHAM BYRT PURLEWENT SPURWAY.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.