Improvements in Compressed Air Engines.
Year: 1898

page_text: Date of Application, 31st May, 1898-Accepted, 6th Aug.,
1898
[Communicated from abroad by LUCIUS TUCKERMAN GIBBS, of 5, East 27th Street,
in the City and State of New York, United States of America, Engineer.]
Improvements in Compressed Air Engines.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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 invention is a compressed air engine in which the cycle of operations is as
follows:-
1. Air is admitted at working pressure and after driving the piston over a
portion of the stroke is cut off and then operates expansively.
2. Gas is admitted at a pressure higher than that of the air existing in the
cylinder at the time of its admission and before the air pressure in the cylinder
by expansion shall have fallen to that of the atmosphere. Hence said gas may be
admitted either before or after the point of cut off of the air--and the point of cut
off of the gas may be either prior to, coincident with, or subsequent to the point
of air cut off. But the gas and air are not admitted simultaneously.
3. After the gas has been admitted and after it has been cut off the mixture of
air and gas is ignited.
The accompanying drawing is a diagrammatic sectional representation.
A is the working cylinder; B the piston; and C the crank shaft. 1) is a reser-
voir of compressed air which communicates with the valve chest E in which is
seated a poppet valve F', actuated by the rod G. In the end of rod G is journalled
a roller H which is acted upon by the cam I on shaft C; said cam is constructed
so as to open and close the valve F in accordance with the timing hereinafter
explained.
J is a reservoir of compressed inflammable gas or vapour which communicates
with a valve chest K in which is seated a poppet valve L which is provided with a
rod M carrying at its end a roller N. Roller Nis acted upon by the cam O on crank
shaft C and said cam 0 is constructed to open and close the valve L in accordance
with the timing hereinafter explained.
When the valve L is open the gas or vapour can pass by a duct P to a chamber Q
which opens at R directly into cylinder A. In the chamber Q is an electric
igniting device S, connected in circuit and operated to ignite the gas in said
chamber at the proper time, also as hereinafter explained.
Finally, communicating with cylinder A is a valve chest T in which is seated a
poppet valve U which has a rod V carrying at its end a roller W. Roller W is
acted upon by cam X on shaft C and said cam is constructed to open and close the
valve L to permit or cut off exhaust from the cylinder A in accordance with the
timing hereinafter explained.
The operation and timing of the engine which is here single acting is as
follows:-
Cam I opens the valve F to allow air under working pressure to flow from
reservoir D behind the piston. The piston then begins its stroke. Cam O then

page_text: opens the gas valve L and allows the gas to enter chamber Q from the gas reser-
voir J. In order that this may occur the pressure of gas must exceed that of the
air. A sufficient amount of such gas to heat the air after expansion will therefore
because the gas is at such high pressure-enter the chamber Q in a very brief
time. Consequently the cam Ŏ may allow valve L to close and so cut off the
gas before cam I allows valve E to close and so cut off the air.
When however the valve E closes then the air operates expansively and at
any time after this point of cut off the circuit may be established through the
igniting device S and the previously admitted gas ignited thus restoring the heat
lost during expansion.
On the return stroke, the exhaust valve U, which hitherto has been kept shut,
is opened by its cam X and the expanded air escapes into the atmosphere.
While it is essential that air alone shall enter the cylinder at working pressure
and so start the piston, it is not essential that the gas shall enter prior to the point
of cut off of the air. It may be admitted after the point of cut off when the air
is at any desired pressure not substantially that of the atmosphere. Hence, it
will further be apparent that there may be considerable latitude in gas pressure,
in the moment of gas admission and in the time during which said admission
continues the last of course depending upon the differential between the pres-
sure in the cylinder and the pressure in the gas reservoir. Obviously if the timing
be such that the period of gas admission is subsequent to the period of air cut
off, then so high a pressure in the gas reservoir is not necessary as when the gas
admission precedes the air cut off both periods of admission being equal in
duration. On the other hand, if the gas be at pressure superior to that of the
original air then the period of admission taking place after air cut off may be
shorter in duration than if occurring prior thereto.
The term "
gas" as herein used means any inflammable vapor or any inflam-
mable fluid in the form of spray or other comminuted condition.
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:-
A motor in which air under working pressure and gas or inflammable vapor
also under pressure are independently admitted, provided with valves for con-
trolling the admission of said air and gas, and an igniter; the said parts being
organized and timed so that the gas enters the motor cylinder when the air
previously admitted therein is at a certain pressure and is subsequently ignited
when said air is at a certain lower pressure whereby the heat lost by the working
air during expansion in said motor is restored.
Dated this 31st day of May 1900
HASELTINE LAKE & Co.,
45, Southampton Buildings, London, W.O.,
Agents for the Applicant.