IMPROVEMENTS IN GAS ENGINES
Year: 1884

page_text: We EDWARD JOHN COWLING WELCH of Palace Chambers St Stephens West-
minster, Civil Engineer and RICHARD CHRISTOPHER RAPIER of 5 Westminster
Chambers, Victoria Street, Westminster Civil Engineers, do hereby declare the
nature of our invention for "IMPROVEMENTS IN GAS ENGINES to be as follows:
Our Invention has for its object improvements in gas engines, and refers more
particularly to gas engines such as are described in the Specification of a Patent
granted to us and dated the 29th day of December last No 5929 and to other gas
engines of that class in which the gas is not exploded, but is burned quietly and
continuously under pressure, in a separate chamber; the products of combustion
passing on to the working cylinder, where they are utilized in giving motion to the
engine.
In the first place we so construct both the suction and delivery valves of our gas
and air pumps; that, when the valves are upon their seats, the pump pistons can
approach them so closely, that there is practically no clearance whatever. We do
this by bringing the valve seats right through the pump covers and finishing them
off flush inside. In the case of the suction valves, we let the valve head into the
seat, so that when the valve is closed it is quite flush across the top, or we face off
the top of the valve flush with the face of the seat, leaving nothing beyond the
mitre.
In the case of the delivery valves we carry the main body of the valve, right
through the seat, so that, when closed, it may be flush with the edge of the seat
itself. Below where the valve takes its proper bearing, the seat is bored out
slightly larger and the valve somewhat reduced in size to allow for the reduced
diameter of the annulas there when the valve opens. The valves and their seats
are so arranged that they can be readily withdrawn for examination, repair or
renewal without disturbing any pipe connections or joints, and they are guided
and checked in their motion, on that side which is furthest from the pump piston,
and their opening and closing may be further regulated by a spring, or other
means,
In order to vary the amount of air and gas which the pumps are to deliver, we
cause either the suction or the delivery valves to remain open for a certain
proportion of the stroke of the pump piston; when, in the ordinary course of things,
they would be closed. If the suction valves be kept open for a time during the
46
A

page_text: forward stroke of the pump piston then a certain proportion of the air or gas, as
the case may be, which has been drawn in, is returned into the suction passage,
and the amount left in the pumps to be compressed and delivered, is thereby
reduced. If on the other hand, the delivery valves be kept open during a portion
of the return stroke, then the compressed air or gas will follow the pump piston
back during a corresponding portion of that stroke, and it will draw in so much
the less new air or gas during that stroke. In other cases we effect the same
object by making a direct communication between the two ends of the pump
cylinders, which is kept open during a variable part of the early portion of each
stroke.
Whichever method we adopt, we are able to couple the valves up, so that they
may be controlled by the governor, which controls the admission of the products of
combustion into the working cylinder of the engine. We are also able to control
the regulating apparatus of the pumps by means of a piston or a flexible
diaphragm opposed by a weight or spring and actuated by the pressure of the
combusted gases in the reservoir or combustion chamber, so that the delivery of
the pumps is controlled direct by the pressure required within the combustion
chamber itself.
The gas and air are delivered separately into different chambers formed in the
base of what constitutes the furnace situated within the combustion chamber and
combustion takes place as the gas and air are brought together in what are termed
tbe burners, the construction of which ensures thorough combustion taking place.
These burners which may be made of any suitable material, consist of a tube of
cylindrical, conical or other suitable form, closed at one end and open at the other.
A suitable opening or openings being made in the closed end for the passage of the
gas into the tube, while either narrow slits, or rows of holes are made lengthwise
of the tube for the admission of the air. One or more of these burners is fixed,
having its closed, or gas entrance end, fitted closely into a hole leading into the
gas chamber of the furnace, while the body of the burner itself extends through
the air chamber of the same, and out into the combustion chamber it being made
sound and air tight where it passes out through the air chamber.
When at work,
the gas enters through the end of the burner and the air enters by all the slits or
holes extending along its length. The gas thus mixes with more and more air as
it passes along, until a point, is reached at which it can commence to burn, and
where carbonic oxide is first formed, by the initial combustion. As more air
becomes mixed with this carbonic oxide, it is converted by further combustion into
carbonic acid and the combustion is thus complete. Intense heat is thereby
generated and there is no gas left unconsumed.
In order to regulate and maintain a continuous combustion, we place above the
burner, or burners, a quantity of broken pieces of fireclay, or other refractory
material so as to form a highly heated mass which further ensures the more perfect
combustion of the gas, and maintains it alight, even after the engine has been
stopped for some minutes. Besides which the temperature of the combusted guses
is kept more constant and regular. In some cases we place a perforated cap or
cone over the burner, or burners, so as to form a continuation of the burner or
burners and thus give more room for perfect combustion. This cover also keeps
the broken fireclay from choking up the burners.
The products of combustion, however, are at too high and destructive a
temperature to be sent direct into the working cylinder of the engine. To reduce
their temperature we therefore mix them with an excess of air; which, while
requiring a larger air-pump, will enable more than a correspondingly larger
working cylinder to be adopted in the engine as there will be so much less loss by
radiation throughout the whole apparatus.
Instead of using an excess of air, a proportionate quantity of water may be used,
which being converted into steam will reduce and partly utilize the excessive
temperature, and assist to lubricate the working cylinder.

page_text: The method we have adopted for adding the water is as follows, Surrounding
and forming the casing of the furnace itself we place a coil of iron pipe, of as many
convolutions as there is room for within the apparatus, or that may be found to be
desirable. This coil is surrounded by a second coil, the upper end of which is left
open and its lower end is connected to a pipe which leads directly to the upper
part of the combustion chamber, This chamber is by preference, made of the
cylindrical form and is placed upright; and it is divided at a short distance from
the top, by a tray or disc, made fast. The upper inlet of the outer coil is beneath
this tray, while the pipe which comes from the lower end of it, terminates above
the tray. The upper end of the inner coil is also brought into the space above the
tray, where it and the end of the pipe from the lower end of the outer coil, unite
in a tee piece, the outlet of which points downwards just above the centre of the
tray and is closed at the end, a number of small holes being made around the side.
In the centre of the tray there is a hole made into which is screwed a nozzle
projecting below and entering the open mouth of the upper end of the outer coil,
which is bent round into the centre, and turned upwards to receive it. This nozzle
merely just enters the mouth of the coil pipe which is made large enough so as not
to be obstructed by it. The lower. end of the inner coil is connected direct to the
water pump, or other source of water supply, and the water passes slowly upwards
throughout the convolutions of the coil becoming heated, and to some extent
converted into steam, in its course. The steam and such of the water as is not
converted into steam, then escapes into the tray through the perforations in the tee,
and it runs down through the nozzle in the centre and enters the outer coil.
The heated products of combustion also enter this coil through the space left
around the nozzle and they and the water pass down throughout the length of the
coil together, the remainder of the water thus being converted into steam; which
with the products of combustion then reduced to a safe temperature pass up
through the return pipe into the space above the tray through the perforated tee
to which this pipe is also attached. The pipe to the engine is also connected into
this space which acts as a steam trap and separates the water which again enters
the outer coil The water pump may also be controlled as to the amount it shall
deliver by similar means to those described for the gas and the air pumps and be
worked in harmony with them. Or the water supply may be controlled as
indicated in the Patent referred to by a thermostat or by other suitable means
such as a float.
As
In starting the engine gas is turned on from the main and air is admitted
through an opening or openings at the bottom of the furnace it being drawn in
either by the action of the gas itself or by an outlet from the combustion chamber
being connected to a flue or chimney. The mass of broken fireclay would thus
become highly heated as also the two coils of pipe and the whole apparatus.
soon as this takes place the free supply of gas and air as well as the outlet from
the chamber are closed and water being admitted to the coil either by turning the
engine a few times round or by a hand pump or other means the pressure is
immediately generated in the combustion chamber and the engine starts off at full
speed.
The action of the furnace may be observed through a strong piece of glass
mounted in a tube passing through the side of the combustion chamber and beneath
the coils into the furnace itself. This tube also serves for lighting up the furnace
either by removing for the moment the glass or by having an opening in the tube
closed by a plug or a valve just behind the glass itself.

page_text: COMPLETE SPECIFICATION.
-
. We, EDWARD JOHN COWLING WELCH of Palace Chambers, St Stephens
Westminster, Civil Engineer and RICHARD CHRISTOPHER RAPIER of 5 West-
minster Chambers Victoria Street, Westminster Civil Engineer do hereby declare
the nature of our invention for "IMPROVEMENTS IN GAS ENGINES" and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement:-
Our invention has for its object improvements in gas engines and refers more
particularly to gas engines such as are described in the specification of a Patent
granted to us and dated the 29th day of December last No 5929 and to other gas
engines of that class in which the gas is not exploded but is burned quietly and
continuously, under pressure, in a separate chamber; the products of combustion
passing on to the working cylinder where they are utilized in giving motion to the
engine.
In the first place we so construct both the suction and delivery valves of our gas
and air pumps that when the valves are upon. their seats the pump pistons can
approach them so closely that there is practically no clearance whatever. We do
this by bringing the valve seats right through the pump covers and finishing thein
off flush inside. In the case of the suction valves we let the valve head into the
seat so that when the valve is closed it is quitè flush across the top, or we face off
the top of the valve flush. with the face of the seat leaving nothing beyond the
mitre.
In the case of the delivery valves we carry the main body of the valve right
through the seat so that when closed it may be flush with the edges of the seat
itself. Below where the valve takes its proper bearing the seat is bored out slightly
larger and the valve somewhat reduced in size to allow for the reduced diameter of
the annulus there when the valve opens. The valves and their seats are so arranged
that. they can be readily withdrawn for examination, repair or renewal without
disturbing any pipe connections or joints and they are guided and checked in their
motion on that side which is farthest from the pump piston and their opening and
closing may be further regulated by a spring or other means.
Figure 1 of the drawings hereunto annexed shews a plan of one end of the air
pump of the engine. Figure 2 is a section taken through the inlet valves and
Figure 3 a section taken through the delivery valve.
The valves for the gas pumps are constructed in the same way so that we have
not thought it necessary to shew, any drawing of them.
The valve seats A are as shewn carried right through the pump covers and are
finished off on the inside flush with the cover's inner face.-B B are a pair of
suction valves the inner surfaces of the heads of which are flush with the inner face
of the cover when they are closed. C is the delivery valve the inner face of which
is also flush with the inner face of the cover. As shewn by Figure 3 this valve
when closed only fits against the outer part of the conical valve seat whilst an
annular space is left between the inner end of the valve and the smaller end of the
conical valve seat-the object of this is as above stated that when the valve lifts

page_text: there shall be à free passage between the valve and its seat where their diameters
are small so as not to offer any obstruction to the escape of air through the annular
space between the valve and its seat where their diameters are large.
116
The inlet valves are as shewn drawn to their seats by springs D. The stems of
the valves are made tubular and the springs are contained within them. The end
of the stem is closed by a screw plug through which passes a rod E-the spring
surrounds this rod and at one end bears against a collar on its end and at the other
bears against the screw plug above mentioned. The valve stem works to and fro
in a tubular guide F. The outer end of the guide has screwed into it a nut G
through which the rod E passes and is held by a nut H screwed on to its end the
nut G also forms a stop to limit the movement of the valve. I is a screw cup for
closing the extreme outer end of the tubular guide. It will be seen also that the
tubular guide F is formed in one piece with a large screw plug by which the outer
end of the valve box is closed. J, J, are air inlet holes for admitting air to the
interior of the valve box. By constructing the valves and their seats in the above
manner the valves are guided and checked in their motion by parts on the outer.
sides of the valves and the valves and their seats can readily be removed without
disturbing the cylinder covers. The delivery valve is constructed substantially in
the same way except that the valve box has a compressed air delivery pipe led off
from it instead of having air inlet holes.
In order to vary the amount of air and gas which the pumps are to deliver we
cause either the suction or the delivery valves to remain open for a certain pro-
portion of the stroke of the pump piston when in the ordinary course of things they
would be closed. If the suction valves be kept open for a time during the forward
stroke of the pump piston then a certain proportion of the air or gas as the case
may be which has been drawn in is returned into the suction passage and the
amount left in the pumps to be compressed and delivered is thereby reduced. If
on the other hand the delivery valves be kept open during a portion of the return
stroke then the compressed air or gas will follow the pump piston back during a
corresponding portion of that stroke and it will draw in so much the less new air
or gas during that stroke. In other cases we effect the same object by making a
direct communication between the two ends of the pump cylinder which is kept
open during a variable part of the early portion of each stroke:
Whichever method we adopt we are able to control the regulating apparatus of
the pumps by means of a piston or a flexible diaphragm upon or connected to the
stem E the nut H being dispensed with opposed by a weight or spring and actuated
by the pressure of the combusted gases in the reservoir or combustion chamber so
that the delivery of the pumps is controlled direct by the pressure required within
the combustion chamber itself.
The gas and air are delivered separately into different chambers formed in the
base of what constitutes the furnace Situated within the combustion chamber and
combustion takes place as the gas and air are brought together in what are termed
the burners, the construction of which ensures thorough combustion taking place.
These burners which may be made of any suitable material consist of a tube of
cylindrical conical or other suitable form closed at one end and open at the other.
A suitable opening or openings being made in the closed end for the passage of the
gas into the tube while either narrow slits or rows of holes are made length wise of
the tube for the admission of the air. One or more of these burners is fixed
having its closed or gas entrance end fitted closely into a hole leading into the gas
chambers of the furnace while the body of the burner itself extends through the
air chamber of the same, and out into the combustion chamber; it being made
sound and air-tight where it passes out through the air chamber. When at work
the gas enters through the end of the burner and the air enters by all the slits or
holes extending along its length. The gas thus mixes with more and more air as
it passes àlong until a point is reached at which it can commence to burn and where
carbonic oxide is first formed by the initial combustion. As more air becomes
mixed with this carbonic oxide, it is converted by further combustion into carbonic

page_text: acid and the combustion is thus complete. Intense heat is thereby generated and
there is no gas left unconsumed.
In order to regulate and maintain a continuous combustion, we place above the
burner or burners a quantity of broken pieces of fireclay, or other refractory
material, so as to form a highly heated mass, which further ensures the more
perfect combustion of the gas, and maintains it alight even after the engine has
been stopped for some minutes. Besides which the temperature of the combusted
gases is kept more constant and regular. In some cases we place a perforated cap
or coue over the burner or burners, so as to form a continuation of the burner or
burners and thus give more room for perfect combustion. This cover also keeps the
broken fireclay from choking up the burners.
Figures 4 and 5 shew two vertical sections taken at right angles to one another
of a burner constructed in the manner we prefer for carrying out this part of our
invention.
In these figures A is a portion of the bottom plate of a hot air chamber-B is the
burner the upper part of which fits into an opening through this plate. The sides
of the burner are perforated and are surrounded by an air chamber C into which
air can be admitted through an inlet valve D or by a pipe E coming from the
air pump of the engine. The lower end of the burner opens into a chamber F to
which gas can be supplied from the gas main by a pipe G fitted with a stop cock
not shown or from the gas pump of the engine by a pipe H. I is an inverted cone
of fire clay fitted into the interior of the hot air chamber and J is a perforated
arch of fire clay placed across the lower part of the cone I through the perforations
in which the products of combustion arising from the burner can pass into the hot
air chamber. Above the perforated arch J broken pieces of fireclay or other
refractory material may as above stated be piled in the inverted cone I if desired.
When the engine is to be started the stop cock D on the air inlet and the stop
cock on the pipe G from a gas main are first opened and the gas ignited above the
perforated arch J by introducing a light through pipe K which passes to the
exterior of the hot air chamber. When the gas has been lighted it is allowed to
burn for a time to heat the burner afterwards the outer end of the pipe K is closed
by a cap provided for the purpose, the stop cocks above mentioned are closed and
a few turns are given by hand to the crank shaft of the engine to supply gas and
air to the burner until the pressure within the hot air chamber is sufficient of itself
to work the engine.
Modified ways of forming the burner are shewn at Figures 6 and 7. In the
construction shewn at Figure 6 several burners similar to the one above described
are ranged in a circle. In the construction shown at Figure 7 a certain amount of
air is allowed to mingle with the gas before it enters the burner-this small supply
of air passing to the gas through the small holes L.
The products of combustion however if used alone would be at too high and
destructive a temperature to be sent direct into the working cylinder of the engine.
To reduce their temperature we therefore mix them with an excess of air; which
while requiring a larger air pump will enable more than a correspondingly larger
working cylinder to be adopted in the engine as there will be so much less loss by
radiation throughout the whole apparatus. This excess of air may be supplied
through the perforations in the upper part of the burner or may be allowed to pass
into the hot air chamber from the air chamber which surrounds the burner through
passages provided for the purpose.
Instead of or in addition to using an excess of air a proportionate quantity of
water may be used, which being converted into steam will reduce and partly
utilise the excessive temperature, and assist to lubricate the working cylinder.
The method we have adopted for adding the water is as follows and is illustrated
at Figure 8 which is a vertical section of the hot air chamber. In this figure
A is the outer casing of the hot air chamber and B the burner at the lower part
thereof which may be formed as shown or modified in various ways as described in
reference to Figures 6 and 7.

page_text: Surrounding and forming the casing of the furnace itself we place a coil of iron
pipe C of as many convolutions as there is room, for within the apparatus, or that
may be found to be desirable. This coil is surrounded by a second coil D the upper
part of which is left open and its lower end is connected to a pipe E which leads
directly to the upper part of the combustion chamber. This chamber is by
preference made of the cylindrical form and is placed upright; and it is divided
at a short distance from the top by a tray or disc F made fast. The upper inlet of
the outer coil is immediately beneath this tray while the pipe E which comes from
the lower end of it terminates above the tray. The upper end of the inner coil C
is also brought into the space above the tray when it and the end of the pipe E
from the lower end of the outer coil unite in a tee piece G the outlet of which
points downwards just above the centre of the tray and is closed at the end, a
number of small holes being made around the side. In the centre of the tray
there is a hole made into which is screwed a nozzle H projecting below and
entering the open mouth of the upper end of the outer coil D which is bent round
into the centre, and turned upwards to receive it. This nozzle merely just enters
the mouth of the coil pipe which is made large enough so as not to be obstructed
by it. The lower end of the inner coil C is connected direct to the water pump, or
other source of water supply and the water passes slowly upwards throughout the
convolutions of the coil becoming heated, and to some extent converted into steam,
in its course. The steam and such of the water as is not converted into steam,
then escapes into the tray through the perforations in the tee piece G and it runs
down through the nozzle H in the centre and enters the outer coil D. The heated
products of combustion also enter this coil, through perforations formed as shown
in its end, and they and the water pass down throughout the length of the coil
together, the remainder of the water thus being converted into steam; which with
the products of combustion, then reduced to a safe temperature, pass up through
the return pipe, into the space above the tray or partition F through the perforated
tee piece G to which this pipe is also attached. The pipe I to the engine is also
connected into this space which acts as a steam trap and separates the water which
again enters the outer coil D). The water pump may also be controlled as to the
amount it shall deliver, by similar means to those described for the gas and the
air pumps, and be worked in harmony with them. Or the water supply may be
controlled, as indicated in the Patent referred to, by a thermostat, or by other
suitable means, such as a float.
In starting the engine the gas is turned on. from the main, and air is admitted
through an opening or openings at the bottom of the furnace as above described it
being drawn in either by the action of the gas itself or by an outlet from the
combustion chamber being connected to a flue or chimney. The mass of the broken
fire-clay would thus become highly heated as also the two coils of pipe and the
whole apparatus. As soon as this takes place, the free supply of gas and air, as
well as the outlet from the chamber, are closed, and water being admitted to the
coil either by turning the engine a few times round, or by a hand pump or other
means, the pressure is immediately generated in the combustion chamber, and the
engine starts off at full speed.
The action of the furnace may be observed through a strong piece of glass
mounted in a tube passing through the side of the combustion chamber and
beneath the coils, into the furnace itself. This tube also serves for lighting up the
furnace, either by removing for the moment, the glass or by having an opening in
the tube closed by a plug, or a valve just behind-the glass itself.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed we declare that what
we claim is
1. In gas engines worked by the products of combustion of gas burnt con-
tinuously under pressure in a combustion chamber the construction of the suction
valves and valve seats of the gas and air pumps in such manner that they are when

page_text: the valves are closed flush with the inner surface of the cylinder covers substantially
as described.
1
2. The construction of the delivery valve and valve seat substantially in the
manner described so that when the valve is closed its inner end is flush,with the
inner face of the cylinder cover whilst a slight space is left between the inner end
of the valve and the valve seat for the purpose described.
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3. The construction of the valves valve seat and boxes substantially in the
manner herein before described and illustrated in the Drawings annexed.
4. The means substantially as herein before described for varying the amount of
gas and air which the gas and air pumps of the engine are allowed to deliver.
5. The construction of the burners of the furnace substantially in the manner
herein before described and illustrated in the Drawings.
6. The means substantially as herein before described for admixing air with the
products of combustion in the furnace or hot air chamber.
7. The means substantially as herein before described for admixing steam with
the products of combustion in the furnace or hot air chamber.