Improvements in Gas Engines.
Year: 1893

page_text: Date of Application, 11th Apr., 1893
Complete Specification Left, 10th Jan., 1894-Accepted, 10th Feb., 1894
Improvements in Gas Engines.
I, HENRY THOMAS DAWSON, of Salcombe, in the County of Devon, Gentleman,
do hereby declare the nature of this invention to be as follows:-
:-
In order to heat the ignition apparatus of a gas engine I provide for the regular
supply thereto of gas and air mixed in suitable proportions. For this purpose I
use a compound pump which can be worked by the engine and also by hand when
the engine is not running. The pump consists of an external cylinder which is
open at both ends but has a partition in the middle dividing it into two parts.
The partition carries on each side of it a cylindrical projection concentric with the
outer cylinder and leaving an annular space between the two. Each end of the
cylinder also contains a plunger fitting the annular space. In the centre of
the plunger there is also a cavity which receives the cylindrical projection upon the
partition. One of the plungers can receive a reciprocating movement from the
engine, the other from a hand lever. When the engine is running the hand lever
is suitably secured and remains at rest but the hand lever is worked to obtain a
supply when the engine is not running. The two annular spaces are connected
together by a passage through the partition and in connection therewith an air
inlet valve and an air outlet valve are provided.
Similarly the cavities within the plungers are connected by passages through the
cylindrical projections and the partition and there is a gas inlet valve and a gas
outlet valve in connection with these passages.
Thus when either plunger receives movement, gas and air is pumped
separately.
There is a receiver with a partition which divides it into two chambers and into
these the gas and the air are separately compressed. It will be seen that when the
engine is at work the position in which the hand lever is fixed regulates the
pressure which can be generated in the receiver so that whatever the consumption
may be, the pressure can never rise above that to which the apparatus is set.
The ignition apparatus receives a supply of mixed gas and air from a mixing box in
connection with the receiver. The mixing box is provided with stop valves which
can be opened more or less as required.
Between the mixing box and the ignition apparatus I interpose a filter or
strainer. It consists of a tube closed at one end and with a series of annular
grooves turned on its exterior; in these grooves are numerous fine perforations.
The tube is wound round with fine wire gauze so that several thicknesses of gauze
envelope the tube. The arrangement is such that the gas and air being admitted
to the interior of the tube, pass out through the perforations and through the
gauze; the mixture so enters an outer tube or case which is in direct communication
with the heating chamber of the ignition apparatus.
The arrangement may obviously be varied by reversing the direction in which
the gas and air flow through the filter or strainer.
I ensure in this way a complete admixture of the air and gas and also render
t impossible for flame to pass back from the ignition apparatus to the mixing
chamber.
The proper proportion in the mixture of gas and air is ensured by the observation
of a test burner consisting of a metal tube lined with refractory material and with

page_text: a diaphragm of wire gauze at the lower part. A cone valve admits the mixed
gases beneath the wire gauze and the mixture is burnt above the gauze.
The nature of the flame shows when the adjustment is suitable.
Dated this 10th day of Anril 1893
HENRY T. DAWSON.
Improvements in Gas fine.
I, HENRY THOMAS DAWSON, of Salcombe, in the County of Devon, Gentleman,
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:―
In order to heat the ignition apparatus of a gas engine I provide for the regular
supply thereto of gas and air mixed in suitable proportions. For this purpose I
use a compound or duplex pump which can be worked by the engine and also by
hand when the engine is not running. The pump consists of an external cylinder
which is open at both ends but has a partition in the middle dividing it into two
parts. The partition carries on each side of it a cylindrical projection concentric
with the outer cylinder and leaving an annular space between the two. Each end
of the cylinder also contains a plunger fitting the annular space. In the centre of
the plunger there is also a cavity which receives the cylindrical projection upon the
partition. One of the plungers can receive a reciprocating movement from the
engine, the other from a hand lever. When the engine is running the hand lever
is suitably secured and remains at rest but the hand lever is worked to obtain a
supply when the engine is not running. The two annular spaces are connected
together by a passage through the partition and in connection therewith an air inlet
valve and an air outlet valve are provided.
Similarly the cavities within the plungers are connected by passages through the
cylindrical projections and the partition and there is a gas inlet valve and a gas
outlet valve in connection with these passages.
Thus when either plunger receives movement, gas and air is pumped separately.
There is a receiver with a partition which divides it into two chambers and into
these the gas and the air are separately compressed. It will be seen that when the
engine is at work the position in which the hand lever is fixed regulates the pressure
which can be generated in the receiver so that whatever the consumption may be,
the pressure can never rise above that to which the apparatus is set. The ignition
apparatus receives a supply of mixed gas and air from a mixing box in connection
with the receiver. The mixing box is provided with stop valves which can be
opened more or less as required.
Between the mixing box and the ignition apparatus I interpose a filter or strainer.
It consists of a tube closed at one end and with a series of annular grooves turned
on its exterior; in these grooves are numerous fine perforations. The tube is
wound round with fine wire gauze so that several thicknesses of gauze envelope the
tube. The arrangement is such that the gas and air being admitted to the interior
of the tube pass out through the perforatious and through the gauze; the mixture
so enters an outer tube or case which is in direct communication with the heating
chamber of the ignition apparatus.
The arrangement may obviously be varied by reversing the direction in which
the gas and air flow through the filter or strainer.
I ensure in this way a complete admixture of the air and gas and also render it
impossible for flame to pass back from the ignition apparatus to the mixing
chamber.
The proper proportion in the mixture of gas and air is ensured by the observation
of a test burner consisting of a metal tube lined with refractory material and with a

page_text: adjustment is suitable,
In order that my said invention may be fully understood and readily carried into
effect I will proceed to describe the drawings annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 shows an elevation partly in section of a pump iu accordance with my
invention for compressing gas and air into store reservoirs. The reservoirs and the
mixing chamber are also shown in this figure.
Figure 2 is a section of the reservoirs.
Figure 3 is a longitudinal section of parts of the pump to a larger scale.
Figure 4 is a transverse section of the pump.
Figure 5 is a vertical section of the mixing chamber.
Figure 6 is a vertical section of the testing burner.
Figure 7 shows in section the gas filter or strainer which serves to produce
complete mixture and also to prevent flame from passing back.
The pump which supplies the gas and air under pressure consists of a cylinder 1
within which there is fixed a partition 2 carrying two rams 2* 2*. There are also
two plungers 3, 4. The plunger 3 receives a reciprocating movement from an
eccentric upon the crank shaft of the engine. A similar movement can be imparted
to the plunger 4 by means of the hand lever 0. The hand lever is worked only to
get up pressure before first starting the engine, at other times it is locked fast.
The plungers 3, 4 have cylindrical cavities in them and corresponding rams 2×2×
on the partition 2 project into the cavities in the plungers. There are passages
bored through the rams 2× 2x and branch passages leading to valves 5, 6. When
the plunger 3 or 4 moves outward or away from the central partition 2 a partial
vacuum is formed and gas enters the central space from the gas main by the
valve 5. When on the other hand the plunger moves inwards towards the partition
the gas is compressed and passes out by the valve 6 into the reservoir 7. The
anuular space within the cylinder 1 and around the rams 2* 2* is connected with
inlet and outlet valves 8, 9 and communication from one side of the partition to the
other is established by a passage 2º. The movement of the plunger causes air to
enter the cylinder by the valve 8 and to be delivered by the valve whence it
passes into the reservoir 10. The connecting pipes leading to the valves 5, 6, 7, 8,
are omitted in Figure 4. The pressure which the pump is able to generate depends
on the relative dimensions of the clearance spaces and plungers and this can be
varied at will by moving the handle 0 and clamping it in another position. The
apparatus is preferably so arranged that the reservoirs 7 and 10 can be charged
each to about one atmosphere pressure and this pressure be maintained uniformly
whilst the engine is at work. 11 is the pipe by which gas enters the mixing
chamber from the reservoir 7 and 12 is the pipe by which air enters the mixing
chamber from the reservoir 10. Valves 13, 14, which can be adjusted by hand
control the supply to the mixing chamber. h is the pipe which leads the mixed
gas and air to the ignition apparatus. I connect with the mixing chamber the
testing burner shown by Figure 6; it consists of a metal cylinder 15 with a
valve at the lower part by which the gaseous mixture is allowed to enter; it
passes upwards through a diaphragm 16 of wire gauze into the upper part
of the cylinder which is lined with fire clay or other refractory material.
If the gas burns with a low flame and the refractory lining becomes highly
heated the mixture is suitable; if not it can be easily regulated by the hand
valves 13, 14.
The igniting apparatus of the gas engine and its furnace chamber may be
arranged as heretofore and in any suitable manner. Preferably between the
mixing chamber and the igniting apparatus I interpose the parts shown by
Figure 7. In this figure h¹ is a continuation of the pipe 7, it terminates in the

page_text: tube 17 in which a series of annular grooves 17* are turned. In these grooves 17*
a number of fine perforations are formed by which the gaseous mixture can pass
out. The tube 17 is wrapped round several times with fine wire gauze 18 which is
secured in its place with binding wire. 19 is a cap which goes over the whole;
it screws at its lower end on to the tubular part 17 and at its upper end it delivers
the mixed gases directly to be burnt to supply the necessary heat to the igniting
apparatus of the gas engine. Stop cocks are provided in connection with the
reservoirs 7 and 10 and when the engine ceases to work these are closed to retain a
store of compressed air and gas for starting the engine.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In a gas engine for simultaneously compressing air and gas in due proportion,
a pump having a plunger with a cylindrical cavity in it and working within a
cylinder containing concentrically a ram entering the cavity in the plunger, and
valves controlling the ingress and egress of air and gas to the cylinder and the
cylindrical cavity respectively substantially as described.
2. In a gas engine for simultaneously compressing air and gas in due proportion,
a pump in accordance with the preceding claiming clause and having two plungers,
one in connection with a hand lever and so arranged that by setting it in various
positions the pressure to which the gas and air can be compressed may be regulated
substantially as described.
3. In a gas engine the combination of parts substantially as described consisting
of a pumping apparatus compressing air and gas, receivers in which the com-
pressed air and gas are separately stored appliances in connection with the
pumping apparatus whereby excessive compression may be avoided, a mixing
chamber and valves admitting the compressed air and gas to the mixing chamber
and a passage in connection with the mixing chamber whereby the gaseous mixture
is drawn off for use.
4. In combination with the apparatus the subject of the second claiming clause,
the safety appliance substantially as described in respect of Figure 7 of the annexed
drawings.
5. For testing gaseous mixtures employed in gas engines, the testing burner
substantially as represented by Figure 6 of the annexed drawings.
Dated this 23rd day of December 1893.
HENRY T. DAWSON.