MENTS IN GAS ENGINES
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by the said Samuel Withers at the
Office of the Commissioners of Patents on the 27th January 1882.
SAMUEL WITHERS, of Torquay, in the County of Devon, Engineer.
MENTS IN GAS ENGINES."
66
IMPROVE-
This Invention relates to the improvements hereinafter described in gas
engines.
In carrying out my Invention I employ any suitable cylinder and piston, which
may be placed either horizontally or vertically, but I prefer employing a cylinder
of sufficient length as to leave a chamber below the piston at the end of its down-
ward stroke, such chamber being employed to contain air to serve as a cushion,
the usual crank shaft and fly wheel are employed.
I employ a slide valve so constructed as to effect the three operations of
supplying the explosive mixture to the cylinder, of igniting the said charge, and of
discharging or exhausting the products of the exploded chargo.
In a suitable construction of valve for this purpose the valve has three cavities,
the centre one of which serves for the supply of the explosive mixture, a second
and wider cavity serves for the exhaust or outlet during the down stroke of the
piston, and a third cavity carries the jet for igniting the mixture. On the com-
mencement of the up stroke of the piston, the slide valve is (by the action of the
hereinafter described cam on the crank shaft) thrown forward about one half of its
stroke, so as to bring the herein before described centre cavity or passage in the
valve in communication with the inlet port of the cylinder, and with a port in the
valve cover, the valve then remains stationary a certain time for the purpose of
allowing the supply of a full charge to the cylinder, the air is drawn from the
herein before described port in the cover, and the gas through a small port in the
cylinder face from the usual gas bag or other reservoir on the regulating valve
hereinafter described. On the supply of the explosive mixture being cut off by
the further forward movement of the valve, the cavity containing the igniting jet

page_text: is brought opposite the cylinder port through which the gases have just passed
and the ignition then takes place, the jet is extinguished by the explosion and a
portion of the products of the combustion is forced into the nipple, and as this
would interfere with the relighting of the jet the amount of travel left for the
valve after the explosion allows the gas passage in the valve to be brought in
communication with the exhaust port, which effectually relieves the nipple from
the products of combustion forced into it as herein before described by the explosion.
The jet is relighted on the return stroke of the valve by a fixed jet kept
burning outside the cylinder, the ignition jet being supplied with gas through a
passage in the slide valve communicating with a passage in the cylinder face, just
before the valve reaches the end of its stroke the jet ignites the charge as
hereinbefore described.
The return stroke of the valve brings the wider cavity thereof in communication
with the cylinder port, and allows the exhaust from the back stroke of the piston
to pass through the said cavity to the exhaust port, and away through a pipe
provided for the same.
For the purpose of insuring a uniform supply of gas to the cylinder at each
charge and to prevent the escape of gas in the event of accidental stoppage of the
engine, I provide a valve so constructed as to allow the gas from the main to flow
first into the usual bag or other reservoir, whence it is drawn into the cylinder
through the passages in the cylinder face and valve in the following manner.
When the slide valve has nearly reached the limit of its back or out stroke the
end of the slide valve presses the spindle in the gas valve and opens a passage
from the gas main, into the gas bag or other reservoir, the connection between the
bag and cylinder being at this time cut off. When the valve moves forward as
before mentioned about one half stroke, to admit the charge the spindle of the gas
valve is released and closes-the-connection with the gas main and the new position
of the slide valve opens communication between the gas bag and cylinder, and thic
gas is then drawn into the cylinder from the bag, this arrangement effectually
prevents any overflow of gas into the cylinder and also renders impossible any
escape of gas in the event of stoppage of the engine from any cause.
For working the slide valve 1 employ a cam instead of the usual eccentric, the
said cam is so constructed that on the first motion of the slide valve the ports aro
allowed to remain fully open for the entrance of the charge up to the time of
ignition; this allows a fuller or denser charge to be admitted than if the slide
valve were in motion as in the latter case it would be gradually cutting off the
charge up to the time of explosion, the cam then brings the igniting jet opposite
the cylinder port, allowing but little time to elapse between the completion of the
charging of the cylinder and the ignition of the charge.
After the explosion and before the piston begins to return the cam causes the
valve to move out so as to again open the air port, and cold air enters through
the port into the bottom of the cylinder, while the hot air and expended gases
ascend through a port in the cylinder, thereby allowing a current of cold air to
enter the cylinder so as to both cool and purify the interior of the same.
The remainder of the travel of the slide valve allows the igniting jet to he
brought opposite the standing jet outside the cylinder and to there remain
stationary during one balf revolution giving the whole of this time for relighting
the slide jet thereby increasing the certainty of action and steadiness of working.
For double acting engines a slide valve is employed for each end of the
cylinder.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Samuel Withers in the Great Seal Patent Office on the 27th
July 1882.
SAMUEL WITHERS, of Torquay, in the County of Devon, Engineer. "IMPROVE-
MENTS IN GAS ENGINES."
This Invention relates to the improvements hereinafter described in gas engines.
In carrying out my Invention I employ any suitable cylinder and piston which
may be placed either horizontally or vertically but I prefer employing a cylinder
of sufficient length so as to leave a chamber below the piston at the end of its
downward stroke such chamber being employed to contain air to serve as a
cushion; the usual crank shaft and fly wheel are employed.
I employ a slide valve so constructed as to effect the three operations of
supplying the explosive mixture to tho cylinder, of igniting the said charge, and
of discharging or exhausting the products of the exploded charge.
In a suitablo construction of valve for this purpose the valve has three cavities
the centre one of which serves for the supply of the explosive mixture, a second and
wider cavity serves for the exhaust or outlet during the down stroke of the piston,
and a third cavity carries the jet for igniting the mixture. On the commencement
of the up stroke of the piston the slide valve is (by the action of the hereinafter
described cam on the crank shaft) thrown forward about one half of its stroke so
as to bring the herein before described centro cavity or passage in the valve in
communication with the inlet port of the cylinder and with a port in the valve
cover, the valve then remains stationary a certain time for the purpose of allowing
the supply of a full charge to the cylinder the air is drawn from the berein before
described port in the cover and the gas through a small port in the cylinder face
from the usual gas bag or other reservoir. On the supply of the explosive mixturo
being cut off by the further forward movement of the valve the cavity containing
the igniting jet is brought opposite the cylinder port through which the gases have
just passed and the ignition then takes place, the jet is extinguished by the
explosion and a portion of the products of the combustion is forced into the nipple
and as this would interfere with the relighting of the jet the amount of travel left
for the valve after the explosion allows the gas passage in the valve which supplies
gas to the ignition jet to be brought in communication with an exhaust port which
effectually relieves tho nipple froin the products of combustion forced into it as
hereinbefore described by the explosion. The jet is relighted on the return stroke
of the valve by a fixed jet kept burning outside the cylinder the ignition jet being
supplied with gas through a passage in the slide valve communicating with a
passage in the cylinder face; just before the valve reaches the end of its stroko
the jet ignites the charge as hereinbefore described.
The return stroke of the valve brings the wider cavity thereof in communication
with the cylinder inlet port, and allows the exhaust from the back stroke of the
piston to pass through the said cavity to the exhaust port and away through a
pipe provided for the same.
For the purpose of ensuring a uniform supply of gas to the cylinder at each
charge and to prevent the escape of gas in the event of accidental stoppage of the
engine, I construct the slide valve or provide a valve so constructed as to allow
the gas from the main to flow first into the usual bag or other reservoir whence it
is drawn into the cylinder through the passages in the cylinder face and valve in
the following manner. When the slide valve has nearly reached the limit of its
back or out stroke the slide valve opens a passage from the gas main into the gas

page_text: bag or other reservoir the connection between the bag and cylinder being at this
time cut off. When the valve moves forward as before mentioned about one half
stroke to admit the charge the connection with the gas main is closed and the new
position of the slide valve opens communication between the gas bag and the
cylinder and tho gas is then drawn into the cylinder from the bag, this arrange-
ment effectually prevents any overflow of gas into the cylinder and also renders
impossible any escape of gas in the event of stoppage of the engine from any
cause.
For working the slide valve I employ a cam instead of the usual eccentric, the
said cam is so constructed that on the first motion of the slide valve the ports are
allowed to remain fully open for the entrance of the charge up to the time of
ignition this allows a fuller or denser charge to be admitted than if the slide valve
were in motion as in the latter case it would be gradually cutting off the charge
up to the time of explosion, the cam then brings the igniting jet opposite the
cylinder port allowing but little time to elapse between the completion of the
charging of the cylinder and the ignition of the charge.
After the explosion and before the piston begins to return the cam causes the
valve to move out so as to again open the air port, and cold air enters through
the port into the bottom of the cylinder, while the hot air and expended gases
ascend through a port in the cylinder, thereby allowing a current of cold air to
enter the cylinder so as to both cool and purify the interior of the same.
The remainder of the travel of the slide valve allows the igniting jet to be
brought opposite the standing jet outside the cylinder and to there remain
stationary during one half revolution giving the whole of this time for relighting
the slide jet thereby increasing the certainty of action and steadiness of working.
For double-acting engines-a-slide-valve-is-employed for each-end-of-the-cylinder.
And in order that this Invention may be fully understood I will describe a
vertical single acting engino constructed according to the same with reference to
the accompanying Drawings.
Figure 1 is a vertical longitudinal section.
Figure 2 an end view and Figure 3 a plan section taken through line Y Z of a
gas engine constructed according to my Invention. Figure 4 is a front view of a
portion of the engine shewing the slide valve box drawn to a larger scale than that
at which it is shewn at Figure 2. Figure 5 is a horizontal section taken through
line S T. Figure 6 a like section on line UV and Figure 7 a like section on
line W W, all of Figure 4. Figuro is a separate view of slide valve showing
the ports on its inner face.
The cylinder A¹ is of such a length as to leave a chamber A³ below the piston at
the bottom of its stroke as shown in Figure 1; this chamber A' is employed to
contain air to serve as a cushion. The slide valve A is worked from a cam A³ on a
usual crank shaft A* by means of the rod A³ which is provided with a friction
roller A and works in the guido A7; to the rod A³ is jointed the connecting
rod A8 which actuates the bell crank lever A' the lower arm of which is jointed to
the slide valve A. The helical spring A" tends to keep the roller A° up against
the cam A³ so as to follow its curve.
The slide valve A is so constructed and operated as to supply the explosive
mixture to the cylinder, of igniting the mixture and of discharging the products of
the combustion or explosion. The slide valve box is provided with a chamber H
in which the gas is mixed, with air (which obtains admission at the apertures
shewn at H2 Figures 1, 2 and 6) before entering the chamber A² below the piston.
The slide valve A has the following main ports or cavities as shown at Figures 6
and 8 viz. a centre through port F for supply of the explosive mixture from the
mixing chamber H to the interior of the cylinder, a second and wider cavity G for
the exhaust during the down stroke of the piston, and a third port B containing
the igniting jet. The slide valve has also in its upper part as shown at Figures 5
and 8 a small port or passage M for supplying gas to the ignition jet from a smaller
gas pipe M³ and cavity or passage M' in the cylinder face; the pipe M³ being fitted

page_text: with a cock as shown at Figure 2 and branching off from the main gas pipe M³;
the slide valve has also in its lower part as shown at Figures 7 and 8 a small
double port J which supplies the gas from the aforesaid main gas supply pipe M³
to the gas bag or reservoir Q through the cylinder ports J' and J and the pipe or
passage M shown in dotted lines in Figures 2, 3 and 7.
The inner wall of the slide valve box or cover E has a port H' which conveys
the explosive mixture from the mixing chamber H through the slide valve into the
cylinder; the wall E has also a port R for admitting gas from the reservoir or
bag through the supply pipe M*, the cylinder port J and the slide valve port J
to the mixing chamber H.
K is a small pipe branching off from the main gas pipe M³ and having a jet
nipple for relighting the jet in the slide valve port B after the explosion has put it
out.
D is an exhaust port through the upper part of the cylinder; L is a valve on
the cylinder for relieving the vacuum during the upstroke when starting engine
and for the same purpose in the event of a non-explosion.
The construction and form of the cam A³ and of the slide valve with the parts
connected therewith are such as to produce the following action of the engine.
The explosive mixture such as ordinary lighting gas mixed with atmospheric
air is in the example here shown atmitted at each upstroke of the piston.
Supposing the piston is at the bottom of its stroke as indicated by the dotted
line a a Figure 1 and that the space A below it contains air and that the slide
valve box H contains a mixture of air and gas. The slide valve A is in such a
position that its port F communicates with the cylinder port C and with the valve
box port H' so that the gas mixture in the valve box H passes into the space A²
below the piston. While the latter rises and performs one third of its upstroke
the slide valve remains stationary and the port F fully open; this allows a full or
dense charge and not as with an ordinary eccentric worked slide valve a wire drawn
or gradually decreased admission of the charge.
At about a third of the upstroke the slide valve quickly shuts off the supply
and opens communication between the chamber A and the ignition jet in the slide
valve port B the slide valve is then in about the position shown at Figures 5 and 6.
The force of the explosion or ignition of the gas and air mixture exerts itself on
the piston driving partly by pressure and partly by momentum up the remaining
two thirds of the stroke. Moreover the air which has remained more or less
unmixed in the bottom of the chamber A2 acts as a buffer to absorb the shock of
the explosion and to convert it into an elastic or expansive pressure.
Just before the piston reaches the top of its stroke the piston passes by and
beyond large exhaust port D allowing the products of combustion and remaining
pressure below the piston to escape into that port and a pipe connected thereto.
About the same time the slide valve is moved so as to open communication
between the chamber A² of the cylinder and the atmospheric air by the ports C. B
and H', a rush of cold air will thus pass from here up through the cylinder and
out by the port D thus cooling and purging the cylinder.
The flame at the ignition nipple in the port B becomes extinguished by the
explosion of the gaseous mixture, and a portion of the products of combustion is
forced into the nipple.
In order to clear the nipple in port B of these products the slide valve A just
before it reaches the end of its stroke places this nipple in the port B in
communication with a small exhaust port N by means of a small port or
passage M seen best at Figure 5 which effectually relieves the pressure in the gas
port B and the nipple therein and ensures that the nipple shall be charged with
lighting gas from the pipe M in time for the next stroke. The exhaust from the
port N being led into the bag Q by means of the pipe N¹ shewn at Figures 2
and 5.
During the down stroke of the piston the slide valve A is moved into the
extreme back or right position whereby the exhaust port G is made to communicate

page_text: with the port C thus allowing a free escape of air below the piston together with
any yet remaining products of combustion. While the slide valve stands in this
position as shown at Figure 7 the gas supply flows from the main supply pipe Ms
by the ports J, J and J and the pipe M to the gas bag or other reservoir Q, the
communication between the latter and the interior of the cylinder being at this
time cut off.
As the piston is about to ascend again the slide valve is as at first mentioned
moved forward or to the left about one half of its stroke and brought into a
position for the steady and full supply of explosive mixture by the port C to the
chamber A; but simultaneously the ports J2, J, and R. Figure 7 are brought
opposite each other so that a charge of gas is admitted from the gas bag Q to the
chamber H, where it mixes with the air the admission of gas from the main
supply pipe Ms being meanwhile cut off. It will thus be seen that during the
time that the gas is flowing from the main M³ to the gas bag Q, the connection
with the chamber A³ or interior of cylinder is cut off, and during the time that the
gas is flowing from the gas bag Q to the mixing chamber H, the communication
between the gas bag Q and the main supply pipe M³ is cut off. This arrangement
effectually prevents any overcharge of gas to the cylinder and also renders
impossible any escape of gas in the event of stoppage of the engine from any
cause.
It should yet be added as an important point that the gas nipple in the port B
as soon as the piston begins to descend and while the valve remains stationary in
the extreme position to the right is close to or opposite to the standing gas jet K
which is always burning. By thus giving the whole of this time for relighting
the nipple jet in the port B certainty of action and steadiness of working are
ensured.
And having thus described and ascertained-the-nature-of-this-Invention and-the-
manner of carrying the same into effect I declare that I claim,-
First. The construction of gas engine in which the explosive mixture containing
a measured quantity of gas is admitted freely during a portion of the up or in
stroke of the piston then ignited or exploded such explosion acting against the
piston on the one side and against an air cushion on the other side, the products
of combustion escaping by a port in the cylinder when the piston is at or near the
end of its up or out stroke, an air port being opened by the slide valve at the same
time so as to cause a cooling and purging current through the cylinder means being
also provided for (free exhaust during the down or in stroke and for) clearing the
igniting nipple of products of combustion and for ensuring the relighting the said
nipple all substantially as described.
Second. The combination of parts forming the improved construction of gas
engine as shown on the accompanying Drawing.
Third. The slide valve A in combination with the mixing chamber H and the
ports and passages acting therewith and in combination with the cam A' for
working it substantially as described and shown.
In witness whereof I the said Samuel Withers have hereunto set my hand
and seal this Twenty-fifth day of July in the year of our Lord One
thousand eight hundred and eighty-two.