Improvements in Gas Engines.
Year: 1892

page_text: Date of Application, 16th July, 1892
Complete Specification Left, 15th Apr., 1893-Accepted, 20th May, 1893
PROVISIONAL STOLETATION.
Improvements in Gas Engines.
1, DAVID DAVY, of Wilkinson Street, Sheffield in the County of York, Engineer,
do hereby declare the nature of my invention to be as follows:-
This invention relates to improvements in engines in which the power is obtained
by the explosion of a mixture of compressed air and gas, or other inflammable mixture,
and commonly called gas engines.
1 propose to employ two cylinders one being an explosion cylinder, the other an
air cylinder, and to render the nature of my invention clear I have annexed a sheet
of diagrams to which I shall refer.
According to the arrangement Fig. 1, the cylinders are placed one inside the
other, A being the outer or air cylinder, and B the inner or explosion cylinder.
The inner piston is turned somewhat less than the bore of its cylinder, the outer
piston being made to fit its annular cylinder and provided with suitable packing
rings.
In operation on an outward stroke the inner piston C, commences to draw in a
charge of gas and air, the outer piston D, at the same time drawing in a charge of
air only. In returning, the contents of both cylinders are compressed in their
respective cylinders, the contents of the outer cylinder A, being compressed to a
slightly higher pressure than the contents of the inner cylinder B, in order to stop
any leakage from the inner to the outer cylinder that might occur on account of the
inner piston being less in diameter than its cylinder.
At the end of the compression stroke the mixture in the inner cylinder B is fired,
and the outward stroke is made by the expansion of the gases in the inner cylinder
and the expansion of the air in the outer cylinder A, the latter being due to the
heat absorbed by the compressed air during the passage of heat through the sides
of the explosion cylinder.
Any leakage on account of the inner piston being less in diameter than its
cylinder simply increases the pressure in the outer cylinder without any loss.
At the end of the stroke the exhaust valves are opened, the exhaust from the
outer cylinder being made to pass through the explosion chamber of the inner
cylinder, thereby clearing out most of the products of combustion, and the cycle is
then again repeated.
The air in the air cylinder A, may be made to take up the heat in the explosion
cylinder B, more readily by means of tubes or plates passing through the explosion
chamber of the explosion cylinder B.
The engine may be made as shown in Figure 2, the cylinders being arranged in
line with or at angles with one another, the pistons working in opposite directions.
The engine may also be made as shown in Figure 3, the cylinders being side by
side.
In each case the explosion cylinder is placed within the chamber of the air
cylinder, the cycle being the same as that of Figure 1.
In all cases the outer cylinder A, may (if desirable) be made the explosion
cylinder, and the inner cylinder B, the air cylinder.
Dated the 14th day of July 1892.
ROBT. F. DRURY, C.P.A.,
Bank Buildings, George Street, Sheffield, Agent for Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Gas Engines.
I, DAVID DAVY, of Wilkinson Street, Sheffield, in the County of York, 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:-
This invention relates to improvements in engines in which the power is obtained
by the explosion of a mixture of compressed air and gas, or other inflamable
mixture.
Two cylinders are employed, one being an explosion cylinder, and the other an
air cylinder, and I prefer to use the combination shown in Fig. 1, in the sheet of
drawings accompanying my Provisional Specification in which one cylinder is
placed inside the other."
Reference is to be had to the annexed drawings which illustrate my invention
and form part of the Specification.
Fig. 1, is a sectional elevation of an engine of a horizontal type made according
to my invention.
Fig. 2, is a section through the valves on the line u, b.
Fig. 3, an end elevation."
Similar letters of reference indicate similar parts in any of the figures.
The object of my invention is, first, to dispense with the necessity for lubricating
the explosion cylinder, enabling the same to be worked at a higher temperature
than usual and thus effecting economy; second, utilising the heat from the walls of
the explosion cylinder and explosion chamber, to expand the air in an outer cylinder;
and thirdly, to effect a more perfect clearance of the explosion chamber from the
products of combustion, by which a higher efficiency is obtained.
A, is the explosion (or inner) cylinder, and B, the air (or outer) cylinder, having
their respective pistons A', and B', coupled together and connected with the crank
shali by means of a connecting rod which I have not shown.
The inner piston A', is turned somewhat less in diameter than the bore of its
cylinder, but the outer piston 13, is made to fit its cylinder and is provided with
suitable packing rings. C, is the gas and air valve F, the exhaust valve from air
cylinder B, and G the exhaust valve from explosion chamber, D gas valve, E air
valve, H the governor, ignition tube.
In operation on the outward stroke, the inner piston A', commences to draw in a
charge of air and gas through the valves D, and C, the admission of gas being
controlled by a governor H. At the same time the outer piston B, cominences to
draw in a charge of air only through valve E.
$
In returning, the contents of both cylinders are compressed in their respective
cylinders, the contents of the air cylinder B, being compressed to a slightly higher.
pressure than the contents of the explosion cylinder A, in order to stop any leakage
that otherwise might occur on account of the inner piston being of smaller diameter
than its cylinder.
At the end of the compression stroke the mixture in the explosion cylinder is
fired, preferably by means of the hot ignition tube I, and the outward stroke is
made by the expansion of the gases in the explosion cylinder A, and the expansion
of the air in the air cylinder B, acting upon their respective pistons, the latter
being due to the heat absorbed by the compressed air during the passage of the
heat from the sides of the explosion cylinder and explosion chamber.
The air in the air cylinder A, may be made to take up the heat in the explosion
cylinder B, more readily by means of tubes or plates passing through the explosion
chamber of the explosion cylinder B,
Any leakage on account of the inner piston A', being less in diameter than its
cylinder, simply increases the pressure in the outer cylinder (without any loss)..

page_text: At the end of the stroke the exhaust valves F, and G, are opened simultaneously
and the pistons returning, the exhaust from the outer cylinder B, passes through
the valve F, opening into the inner cylinder A, and with the exhaust in the said
oylinder A, passes out through valve G, thus clearing out most of the products of
combustion.
At the end of the stroke the exhaust valves are closed and the cycle is repeated.
If found desirable, I may reverse this order and make the outer cylinder the
explosion cylinder and the inner cylinder the air cylinder.
I do not bind myself to use the various mechanical details for actuating the
valves, as they do not form any part of my
invention.
Having now. particularly described and ascertained the nature of my said
invention and in what manner the same may be carried into practice, I declare
that what I claim is :-
In a gas engine, the combination with an explosion cylinder, of an air cylinder,.
so constructed and arranged that a portion of the heat from the walls of the explosion
cylinder or from the explosion chamber will be taken up by the compressed air in
the air cylinder, and converted into work, substantially as herein before described
and shown.
2-In a gas engine, the combination with an inner explosion cylinder A, of au
outer air cylinder B, their respective pistons A', aud B', being coupled together,.
so arranged that the heat from the inner explosion cylinder and its explosion
chamber, will be absorbed by the air in the outer air cylinder for the purpose
specified, substantially as herein before described and illustrated in the annexed
drawings.
3-In a gas engine, such as herein before described, the combination with the-
two cylinders A and B, of their exhaust valves F, and G, in the manner shewn in.
Figs. 1 and 2, for the more perfect clearing out of the products of combustion.
Dated this 14th day April 1893.
ROBT. F. DRURY, C.P.A.,
Bank Buildings, George Street, Sheffield, Agent for Applicant.