Improvements in and relating to Compound Gas Engines.
Year: 1896

page_text: Date of Application, 3rd Mar., 1896
Complete Specification Left, 3rd Dec., 1896-Accepted, 3rd Mar., 1997
Improvements in and relating to Compound Gas Engines.
J, CHARLES HENRY THOMAS ALSTON of 480 Springburn Road Glasgow in
the County of the City of Glasgow, Scotland, Engineer do hereby declare the
nature of this invention to be as follows:-
My invention relates to improvements having for their object the production of
a more economical and perfect engine than those heretofore inade.
The engine as constructed according to my invention comprises a high pressure
or 1st expansion cylinder and a low pressure or 2nd expansion cylinder (herein-
after indicated respectively as the H.P. and L.P. cyldrs.). Usually two pumping
cylinders one each for air and gas are used; though more on compound system
may be used. I may make the ends of a double acting cylinder respectively the
gas and air compressors to a separate receiver. The compressors and receivers
may form part of engine or be entirely separate. I may admit gas along with the
air below explosive stage to air compressor or vist versa. Both air and gas are
compressed isothermally or nearly so and the compressors may be cooled internally
or externally. The H.P. cylinder is placed parrallel and behind the low pressure
cylinder so that a flow port in its side at about outstroke of its piston opens
direct to outer end of L.P. cyldr.; the outer jackets thereof somewhat overlapping
each other. The outer end of the L.P. cyldr. may be internally lined with
suitable nonconducting material in a liner which may be of different lengths and
materials. The piston slides only in the front cool part and carries a non-
conducting shield. On back end of H.P. cyldr. are placed the inlet and
H.P. exhaust valves. The H.P. cyldr. crank leads about 90°.
The H.P. cyldr. piston travels outward followed by compressed mixture from
receiver till about stroke, the supply is then cut off, the charge ignited, and
expansion follows till the flow port to L.P. cyldr. is uncovered. Expansion
continues now in both cyldrs. till H.P. pisten is full out, when L.P. piston will be
about out. The H.P. piston returns compressing the hot charge till it again
covers the flow port and its exhaust valve is opened. Expansion now continues in
L.P. cyldr. till H.P. piston uncovers the flow port allowing L.P. cyldr. to exhaust
through front of H.P. cyldr. While the H.P. piston is travelling outwards over
the flow port cold air may enter the L.P. cyldr. from receiver until H.P. piston
again uncovers flow port when cycle is again repeated as before set forth.
The mixing of the gas and air may be effected by the mouths of two pipes
conveying gas and air opposing each other, and fitted with perforated caps
surrounded by a perforated sleeve. I may employ an additional cut off valve
between the mixer and H.P. cylinder.
The igniting device as constructed according to my invention and applicable to
other engines comprises 3 valves on one spindle; the top and bottom valves close
on their seats upwardly the centre valve downwardly. Holes are placed in the
centre valve such that there is always free communication between the top and
bottom valves in any position. The air holes in seat of centre valve open to
atmosphere; below bottom valve is igniting chamber and in this is another valve
closing mouth of ignition tube. There is a vent hole down centre of this valve
and it may be provided with a stuffing box.

page_text: Water may be forced into the cylinders by a pump driven direct off the crosshead.
The plunger head being at end furthest froin the guide and having two holes there-
through, one to end of plunger the other on other side. Water enters barrel in
ordinary way, is forced through holes in plunger and a delivery valve in crosshead
and hole in piston rod into piston. It returns by a different channel, leaving the
plunger at outlet on the opposite side of head on plunger, thus the pump and
telescope connection are formed in one contrivance.
Dated this 29th day of February 1896.
Engines.
I, CHARLES HENRY THOMAS ALSTON of 480 Springburn Road, Glasgow,
in the County of the City of Glasgow, Scotland, 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
state:nent:-
My said invention relates to improvements having for their object the production
of a more economical and perfect gas engine than those heretofore made; parts of
said improvements also relate to valves, igniting, and piston cooling water,
supplying devices.
And in order to fully understand the invention I have appeuded the annexed
sheets of drawings.
The engine as constructed according to my invention aud shewn in sectional plan
at Fig. A, Sheet I comprises a high-pressure or 1st expansion cylinder a and a low
pressure or 2nd expansion cylinder & hereinafter indicated respectively as the H.P.
and L.I. cylinders. In front H.1'. cylinder is placed a gas compressing pumpe
the front end d of L.P. cylinder constituting a pump for compressing air, both into
separate receivers respectively of common construction (not shewn). The air and
gas may be compressed entirely apart from the motor engine by a separate plant
driven by belt or otherwise. However accomplished, the compression should be
isothermal or nearly so to ensure minimum loss during transmission thro'
receiver to motor cylinders; to reduce volume of motor cylinders, and therefore
surface and weight as much as possible, and to keep the temperature of the cycle
within workable limits, therefore the pumps have water jackets e. I may admit
gas along with the air to air pump and vice versa provided that the combination of
gases is in no case rendered combustible, so that there be no combustible mixture
formed in the engine except in H.P. cylinder and valves provided for the purpose.
The H.P. cylinder a is water jacketted as is also the L.P. cyldr. externally. The
back part of L.P. cylinder and back cover is lined internally with tire brick,
asbestos, or other such heat non conductors . Inside this is a liner to prevent
undue clearance due to the porosity of the non conductor and also to prevent any
of the latter becoming loose. Said liner retains the heat given up to it by the
previous expanding charge and gives it up to incoming cold air. Said liner
made of two pieces of iron, nickel, or other substance suitable for the purpose, and
where it fits the shell it has shrunk on it brass or similar metal rings i so that
although when cold the liner g may be loose and easily withdrawn, yet when hot it
shall be tight against pressure, also if slack when cold then as the liner and brass
rings i get hot the liner y does practically the whole of its longitudinal expansion
belore rings i get tight, thus preventing cracking or deformation of liner.
is
The crank end of the L.P. cylinder being kept cool with water jacket e the

page_text: piston slides therein and has a long extension shieldj projecting into hot end of
L.P.C. which nearly but not quite touches walls of liner g
h
As L.P. piston approaches its in dead centre, cold air is admitted from the
air receiver by the port k into the L. P. cylinder circumferentially at the crank end
of the annular clearance formed between the hot shield; an the hot liner g;
admitting it tangentially gives it a rotary as well as longitudinal notion thus
causing it to circulate well round hot shield j.
On the back end of H.P. cylinder a, are placed the admission and H.P.
auxiliary exhaust valve ense 1.
A port a communicates between the H.1. and LP. cylinders as shewn at Figs. A,
Sheet 1, 50 and 51 Sheet 5 so as to be uncovered by H.P. piston m at about
stroke out. The cranks are placed at or about 90° or 100° apart; the
H.P. crank leading.
Under another modification as diagramatically illustrated at Fig. B Sheet 2 the
motor cylinders may be arranged tanden type the H.P. cylinder a over L.P.
cylinder. The H.P. piston rod a would work inside a fixed tube and drive
its crank set at same angle as herein before described to the double cranks y
wrought by double rods e from L.P. piston A., which piston in this modification
slides over tube a' and has a staffing box and is otherwise made with a shield j and
works relatively in similar way as before described with H.P. piston m. The
pumps c. d. pistons would in this case be both connected by rods E', ', with and
wrought synchronously off L.P. cranks y. The ports and valves would be
relatively located and the operation similarly to those in foregoing modification.
The piston travels out from centre followed by compressed mixture from
receivers till about stroke out, then the supply is cut off and charge is ignited,
by any ordinary means or the igniter hereinafter described, and expansion
continues till about stroke when port a is reached. The piston m now uncovers
port n and the piston being already slightly out expansion goes on in both.
cylinders till piston m is full out and piston about out, then pistou m returns,
but as cylinder & is much larger in diameter than cylinder a expansion continues
till piston m gets back far enough to close port n, then H.P. auxiliary exhaust opens
and piston m gets far enough past port a to open communication through it between
cylinders and a. Exhaust now goes on from both cylinders by part o till piston m
is full in, the cylinder still exhausting when cycle commences as before. Air
admission to cylinder & from port starts when piston his on in dead centre and
piston m has just shut purt a, and continues till L.P. crank has made an angle of
about 20° to 25° then hot gases enter and cycle is repeated as before.
Referring to Fig. C. Sheet 3 which is a sectional plan of valve case on lower
level than cylinder and cover a. the mixing of the air and gas is done as
follows: The mouths of two pipes when such are used, or passages p. q. for air
and gas respectively from inlets py" are placed a short distance apart facing each
other, and covered with perforated or gauze caps py' either Hat or other suitable
shape. Surrounding the ends of passages p, q, is a perforated or gauze sleeve.;
compressed gas and air pass in a lot of small streams at a high velocity through its
own cap, mix with each other, and in passing together through the small holes in
the sleeve, pass through the channel r. past valve . into the cylinder a
thoroughly mixed. The whole arrangement being placed inside of and forms part
of piston valve, acting also as H.P. auxiliary exhaust valve by port a. when valve t
hereinafter referred to, is not used. In most cases I place an ordinary lift valve t
between cylinder a and piston valve in order to get a sudden cut off and obviate
the difficulty of keeping piston valve tight at very high pressures. When valve t
cuts off it is in equilibrium and is closed by a spring è shewn in Fig. A. Late in
the stroke, when pressure in cylinder a. falls below that in clearance on piston
valve side of lift valve t. said pressure opens valve t, and compressed air (as gas
was cut off before air) from clearances comes into and does work in cylinder and
saves waste. The valve t may be kept open by a cam (not shewn) at the proper
moment to allow H.P. cylinder to exhaust.

page_text: The igniting device Fig. D (Sheet 4.) consists of two sets of valves the first set
comprises 3 valves all on one spindle the top and bottom valves 2. close upwardly
and the central open or hollow valve 3 downward on their seats: holes 3 in the
seat of the latter commumicate with the atmosphere. At another part of the
chamber 4. sitante below bottom valve 2 is another valve 5, opening to the ignition
tube 6. This valve has a port down its centre which when the valve is closed to the
ignition tube communicates by vent hole 7 with the interior of tube and the atmosphere
and closes when valve 5 opens tube to chamber. Both sets of valves are driven off
a Tarm & actuated in one direction by the engine and by a spring 9 in tension
in the other. The action is as follows:-Supposing left hand spindle 10 down,
top and bottom valves 2 are open, and valve 3 closed, compressel mixture (gns and
air) enters from port 11 and fills chamber 4. Ignition valve 5 is closed, any
leakage past it goes down centre port to atmosphere and prevents pre-ignition,
presently army is let go by engine and spring 9 pulls it, closing top and bottom
valves 2, and opening valve 3. and ignition valve 5., and closing vent escape in
same. Ignition takes place in chamber 4 and high pressure is attained. Any
leakage past bottom valve 2 escapes through hole 3 to atmosphere thus preventing
pre-ignition in cylinder a. At the proper moment engine pulls arm 8. again thus
opening valves 2 clusiug valve 3., and ignition valve 5, and opening escape from
tube 6. to vent 7. The flame in chamber 4 rushes up through central valve 3.
(valve 3 is unly a bevelled ring fastened to spindle 10 by arnis so that gases pass
it whether open or closed) pnst top valve 2 and projects itself into 11.P. cylinder
ne the flame is at a much higher pressure than the gases in the cylinder. Engine
first closes ignition valve 5. by pulling lower arm 8. further movement merely
compresses the spring 12 shown on its spindle. A spring 13. over spindle 10
allows valve to be closed first, a tube or ferrule being neted on when its arm & is
further depressed to pull down spindle 10 against high pressure. As soon as
bottom valve 2 is a little open the rush of gases leave it more or less in equilibrium
then the spring causes the valve 3 to shut with a snap preventing excessive
snifting at its outlet. A further movement of urin 6 further compresses spring 12
already compressed but to a certain extent set free again by its own action. The
object of spring compression on buth sets of valves is to make sure, valves shall
always close tight notwithstanding the wear of actuating cams, as any wear only
means a little less over compression of springs, 12, 13, which are always in a state
of compression. The top or bottom valves 2, or both, is or are fixed to spindle 10
by a flexible plate or diaphragm 2 shown on top valve which is hest male rather
smaller in diam. than bottom valve. The large spring 9. in tension closes top
valve 2 first then as it continues to pull till it shuts bottom valve 2 (in which it
is assisted by the pressure in the chamber) then bending the flexible plate 21 on
top valve, as top valve was already seated home, this ensures that notwithstanding
one valve wearing more than the other they shall both always be sufficiently
tight.
As shown at Figs. 6, 7, and 8, Sheet 5, water may be forced into the interior of
the compressor or motor pistons. I prefer to pass it along through a hole 15 in
the piston rod with another hole 16 for its return, or I may use 2 pipes or one pipe
divided by a diaphragm 17, Fig. 7, placed in a single hole fored in the centre of the
rods, in this case attach to the eruashead 18 of the engine (pin 27, being fixed in cross-
bend) a rod 20. with a pump piston 19 at the other end. This rod has 2 holes 21, 22,
bored in it which respectively lend to front and back of piston 19 which works in a
harrel 23 fitted with suction valve in ordinary way. The plunger 19 goes in,
displacing water by hole 21, through a delivery valve 24 in erusshead 18 and along
piston rod into piston 25 returning along rod through hole 16 aml out by hole 22
to barrel 23. outlet.
Alternatively I may use a separate ordinary pump 26, Fig. 8, driven by eccentric
or other means; then I use an oscillating arm 28 with a short compensating arm 29,
since crosshead 30 moves in a straight line and arm 28 through an arc, both
arms 28, 29, have two holes 15, 16, therethrough for the conveyance and return of

page_text: water, corresponding holes being made at the joints. Or instead of the separate.
pump 26, for the trunnion on which the oscillating arm is pivotted, could be
substituted a pump of the type known as the "Wing" pump or semirotatory
pump in which case the arm 28 would be keyed to the vibrating piston in said
pump.
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 I
claim is
1. The arrangement, construction and combination of compound gas engines as.
hereinbefore described and shewn.
2. In a gas engine the arrangement and combination of the air and gas supply-
pipes or passages, outlets, and caps and sleeve p, q, s, respectively all as and for the
purposes specified and shewn.
3. The arrangement and combination of piston valves and ports q", 7, u and pl
all as and for the purposes specified and shewn.
4. The arrangement, construction and combination of mechanism constituting-
the igniting device all operating as specified and shewn.
5. The arrangement and combination of mechanism for circulating water inside
reciprocating pistons, as specified and shewn.
6. The construction and combination of liner g, rings i, and nonconductor f as
and for the purposes specified, and shewn in Fig. A.
7. Arranging and locating the ports k and n, as and for the purposes described
and shewn in Fig. A.
Dated this 1st day of December 1896.
DAVID F. MASON, C.E.,
Glasgow, Patent Agent.