IMPROVEMENTS IN GAS-ENGINES
Year: 1879

page_text: LETTERS PATENT to Richard Hallowell, of Blackburn, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN GAS-ENGINES,"
Cooled the 17th Ontohan 1070 and in the 201 1
PROVISIONAL SPECIFICATION left by the said Richard Hallewell at the
Office of the Commissioners of Patents on the 12th April 1879.
RICHARD HALLEWELL, of Blackburn, in the County of Lancaster, Engineer.
"IMPROVEMENTS IN GAS-ENGINES."
My Invention relates in the first place to high-pressure gas engines, and consists
in providing such engines with passages and valves which at suitable points in the
outward strokes of the pistons permit of the flow of the gases from one side of
each piston to the other in order that the remaining pressure of the said gases shall
aid in effecting the return strokes of the pistons. The valve which opens to admit
the gases to the other side of the piston is closed before the exhaust valve is opened,
or such valve may be dispensed with if the exhaust valve is not opened until the
piston in its return stroke has closed the passage of communication. In another
arrangement I admit the gases into a second cylinder previously to the opening of
the exhaust valve, the said second cylinder being preferably larger in diameter than
the first cylinder. In such a case I prefer that the second piston shall have a lead,
so that it is commencing its stroke when the first piston is nearing the termination
of its stroke. In another arrangement I admit the said gases into a reservoir from
whence an engine acting similarly to a hot air engine or otherwise acting may
derive its propelling medium. The said reservoir would be provided with a relief
valve. A second part of my Invention has for its object to facilitate the starting of
high pressure gas engines. I provide a cock or valve, which is opened when the
engine is to be started, and which permits of the escape of the air during part of the
stroke of the piston until the piston passes the port leading to the said cock or
valve, or I provide the engine with a supplementary air compressing pump to be
worked by hand or by a supplementary gas-engine, and which may or may not be
connected with the valve apparatus. A third part of my Invention relates to the
supply of gas. In a former Invention for which Letters Patent No. 4987, in the
year One thousand eight hundred and seventy six, have been granted to me, I
admitted the gas through a perforated plate. I now admit the gas directly into
077

page_text: the cylinder or combustion chamber without previous admixture with air and
without the employment of a perforated plate or part. In one arrangement I admit
the gas into a chamber at the rear of the piston, which chamber can be shut-off
from the cylinder by means of a sliding gridiron or suitable valve. The gas is
drawn into this chamber by means of a pump piston, or is drawn in after the
admission of the charge of air by the continued action of the main piston. The
main piston when making its return stroke compresses the air. At a point in the
said return stroke the said valve is opened so as to admit the compressed air into
the said chamber, and the charge is fired. The said pump piston may or may not
move inwards towards the main piston on or before the opening of the said valve.
This part of my Invention is also applicable to a form of gas engine having
an air reservoir into which air is compressed by the action of the front or forward
side of the piston, as described in the Specification of a former Invention, for
which I have applied for Letters Patent by Petition bearing date the Twelfth day
of December, in the year One thousand eight hundred and seventy eight, and
numbered 5092.
A fourth part of my Invention relates to the cam which has been employed to
govern the engine by regulating the action of the gas-pump so that the stroke of
the said pump. was lengthened or shortened, or that its action was arrested. In
lieu of sliding the said cam I fix it upon its shaft and I slide the bowl upon which
it acts upon a stud or shaft, or I slide the lever carrying the said bowl, or I arrange
the said lover to swivel. A fifth part of my Invention relates to the slide valve. I
so arrange the valve as that the pressure within the cylinder when the gases are
fired tends to press the valve upon its seat. In one arrangement the said valve is
mounted within the cylinder cover, or within a removable cover which is secured
to the cylinder, the joint being by preference carefully faced so that joint packing
can be dispensed with and the valve be quickly removed. In another arrangement
I enclose the valve by means of a removable bonnet, and I admit the pressure within
the said bonnet. A remaining part of my Invention relates to engines provided
with gas pumps. I employ a long hollow piston for the said pump, and I so form
it and the cylinder with passages and ports as that it constitutes the valve of the
engine. By means of the said piston I admit gas and air and I fire the charge, and
in some cases I admit air at times to govern the working of the engine.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Richard Hallewell in the Great Seal Patent Office on the 11th
October 1879.
RICHARD HALLEWELL, of Blackburn, in the County of Lancaster, Engineer.
"IMPROVEMENTS IN GAS ENGINES."
My Invention relates in the first place to high-pressure gas engines, and consists
in providing such engines with passages and valves which at suitable points in the
outward strokes of the pistons permit of the flow of the gases from one side of each
piston to the other in order that the remaining pressure of the said gases shall aid
in effecting the roturn stroke of the pistons. The valve which opens to admit the
gases to the other side of the piston is closed before the exhaust valve is opened, or
such valve may be dispensed with if the exhaust valve is not opened until the piston
in its return stroke has closed the passage of communication. In another arrange-
ment I admit the gases into a second cylinder previously to the opening of the
exhaust valve, the said second cylinder being preferably larger in diameter than the
first cylinder. In such a case I prefer that the second piston shall have a lead, so
that it is commencing its stroke when the first piston is nearing the termination of
its stroke. In another arrangement I admit the said gases into a reservoir, from
whence an engine acting similarly to a hot-air engine, or otherwise acting, may
derive its propelling medium. The said reservoir would be provided with a relief
valve. My Invention relates in the next place to the supply of gas. In a former
Invention for which Letters Patent, No. 4987 in the year One thousand eight
hundred and seventy six have been granted to me, I admitted the gas through a
perforated plate. I now admit the gas directly into the cylinder or into a combus-
tion chamber without previous admixture with air and without the employment of
a perforated plate or part. A remaining part of my Invention relates to the slide
valve. I so arrange the valve as that the pressure when the gases are fired tends
to press the valve upon its seat.
In order that my Invention may be fully understood I have attached hereunto
three Sheets of Drawings marked with letters of reference. Referring to Sheet 1
of the said Drawings, Figs. 1 and 2, drawn to a scale of about one and a half inches
to the foot, are illustrative of the first part of my Invention, the parts of a complete
engine not necessary to the illustration being omitted.
In the said Figs. a, represented in section in Fig. 2, is the cylinder of a hori-
zontal gas engine, and b is the piston, which is connected with a suitable crank
shaft. The forward end of the said cylinder opens into a chamber c, which in the
example is of an annular form, and is provided with a cover d, which can be
removed when it is necessary to obtain access to the piston. The said chamber
also communicates at times with the interior of the cylinder by means of ports e, e,
and is provided with a valve f, which when opened permits air to pass into or out
of the cylinder. The rear end of the cylinder is provided with an exhaust valve g.
The gas
is admitted through a hollow perforated body h, or is otherwise suitably
admitted, and is fired by ordinary or suitable means. When the gas or explosive
mixture is fired the piston moves outwards, during which movement the valve f is
opened by means of a cam on the crank shaft or by a suitable equivalent arrange-
ment, so that the air compressed by the movement of the piston may escape. When
the piston nears the termination of its outward stroke the said valve is closed or is
permitted to close, and the piston now passes the ports e, as seen in Fig. 2, whereby
the high-pressure gases or mixture behind the piston have or has access to the
chamber c. When the piston reaches the termination of its stroke there will be
about the same pressure upon both its sides. The piston now commences its return
or inward stroke, and moves over the ports e, and when these ports are so closed
the exhaust valve g is opened. The piston now completes its inward stroke, aided
by whatever pressure there may be within the chamber c. The said chamber may

page_text: be provided with an inlet valve to prevent the formation of a vacuum; or the
valve fmay be arranged to act as an air inlet valve for the same purpose. The
valve fis connected with the governor in such a manner as that when the governor
nets to shut off the supply of gas it also opens the said valve in order that the air
may be freely drawn into and ejected from the chamber c. The arrangement may
be modified by admitting the gases from the cylinder into the chamber c by means
of a valve, in which case the said valve must be closed at or near the commence-
ment of the inward stroke of the piston and before the opening of the valve g.
The Drawings on Sheet 2, made about one quarter of the full size, are also illus-
trative of the first part of my Invention, Fig. 3 being a side elevation, and Fig. 4
a sectional plan of part of a gas engine having a supplementary expansion cylinder.
In the said Figs. A is the cylinder in which the gases are fired, and B is the
supplementary cylinder. The pistons C and D of the two cylinder are connected
with separate cranks upon the crank shaft, the crank i of the supplementary piston
having an amount of lead as indicated in Fig. 1. The space on the inner side of
the piston D communicates by means of a passage k with a port e, which opens
into the cylinder, as in the first example. A slide f fulfils the same office as
the corresponding valve in Sheet 1. When the piston C nears the termination of
its outward stroke it uncovers the port e, and the gases can then flow into the
cylinder B, wherein they act upon the piston D in aid of the inward stroke of the
piston C. Figs. 5 and 6 illustrate a third modification in the first part of my Inven-
tion, and represent a reservoir or chamber which may be substituted for the
cylinder B. The said reservoir is so attached to or connected with the cylinder A
as that the gases flowing through the port e pass into the said reservoir and are
imprisoned therein by reason of the piston C closing the said port on its return
stroke. The said reservoir provided with a relief valve j. The pressure of gases
obtained within the said reservoir is utilised by conveying the gases to an engine
acting similarly to a hot air engine, or to a high pressure air engine, or to a con-
deusing engine, or to an engine otherwise adapted to utilise the said pressure. The
said reservoir inay be of any other suitable form and dimensions than are indicated.
The two remaining parts of my Invention are illustrated in Sheet 3, wherein Fig. 7
is a side elevation, Fig. 8 a sectional plan, and Fig. 9 an end elevation of the
cylinder of a gas engine, the said Figs. being drawn about one fourth of the full
size. In this example a chamber E is formed in a port which is secured to the rear
end of the cylinder A. A plate K forms a separating partition between the
cylinder and the said chamber. In the said partition a port is formed, and upon
a face prepared on one side of the partition a valve m is arranged to slide, and is
actuated by means of a cam on the crank shaft, or by other suitable means. A
port o is formed in the valve m, and when the ports land o coincide, as when the
valve is in the indicated position there is a direct communication between the
chamber E and the space to the rear of the piston B. The space on the front of
the piston communicates by means of a passage p with a port r in the face of the
partition K, and a third port 8 communicates by means of a passage t with the
interior of the chamber E. When the valve m is moved to close the passage la
cavity establishes a communication between the ports r and 8, so that air
can flow from the front end of the cylinder into the chamber E. The inflammable
gas is supplied by means of a gas pump F, a passage v leads from the cylinder
of the said pump to the sliding gas valve H. This valve is constructed
in accordance with the last remaining part of my Invention. The said valve is
fitted to slide upon a face prepared on the inner side of a cover w, which closes one
end of the chamber E. It will readily be seen that as the valve is on the inner
side of the said cover, the pressure arising from the firing of the gases tends to force
the valve more tightly upon its seating, instead of to force it away from its seating
as in the ordinary arrangement. A stud x passes through a slot in the cover w,
and to this stud is jointed the connecting rod, by means of which the valve is
actuated. The cover w is secured in position by means of bolts and wing nuts y,
in order that it may be readily removed when it is desirable to obtain access to the

page_text: valve, and for the same reason I prefer to make a scraped or faced joint between
the said cover and the chamber E, in order that packing can be dispensed with.
The method of securing the said cover may be varied as considered to be desirable.
When the valve is moved into the firing position, the firing port is brought
opposite a cavity in the valve face, and the gases are fired through a port a¹ in the
valve. When the valve is in the position indicated, the gas from the pump is free
to flow through a port in the valve directly into the chamber E. The action of the
parts is somewhat as follows:-When the piston B moves outwards impelled by
the pressure arising from the fired gases, the air in the space to the front of the
piston is discharged through a valve f which is opened for that purpose. The
piston B now makes an inward stroke, discharging gases through the exhaust valve
g, and drawing in air to occupy the space on the front side through the valve f.
The piston B now makes a second outward stroke by means of the action of the
crank shaft, a firing of gases taking place only at each alternate stroke. The valve
fis closed for this outward stroke, and the valve g open to admit air, and the valve
m is in position to connect the ports 7 and 8, so that the air compressed by the piston
passes into the chamber E. The piston now makes a second inward stroke, dis-
charging air through the valve g, which is then closed for the next acting stroke of
the piston. In the mean time the piston of the pump F has drawn in a charge of
gas, and during the said inward stroke, or during the latter part of it, or whilst the
crank is passing the dead point, the said charge of gas is forced through the passage
v into the chamber. The valve m is moved to open the passage at a suitable
time, and the valve H is moved to fire the gases. The pressure generated within
the chamber E, forces gases at a high pressure through the port 1, to act upon the
piston B, and as a little time is required for the passage of the gases through the
said port, the firing of the gases has not so much the effect of a blow upon the said
piston as when the gases are fired in the cylinder, and the effect upon the piston is
more sustained and regular. The arrangement for supplying the gas may be varied,
and the connecting of the two parts of my Invention is not necessary, that is to
say, an ordinary or suitable form of gas valve may be substituted for the improved
valve represented in the Drawings. The gas not previously mixed with air may be
admitted directly into the cylinder, without passing it through a number of per-
forations in cases wherein the chamber E is not added to the cylinder. Also with
reference to the last part of my Invention, the sliding gas valve arranged within
the cylinder or explosion chamber, or so arranged as that the pressure arising from
the fired gases shall tend to press the valve more tightly upon its seating; may be
applied to other forms of gas engines than are herein indicated, and may be varied
in form and in the disposition of the ports to suit varying requirements. The valvo
may be situated outside the cylinder or firing chamber, in which case I cover it
with a removable bonnet, or enclose it in a valve box which communicates with the
interior of the cylinder or firing chamber, so that the pressure is obtained within
the said bonnet or valve box when the gases are fired, the effect being substantially
the same as in the case of the example illustrated.
In my Provisional Specification, I described my Invention under six beads, but I
have not included herein nor illustrated in the accompanying Drawings the parts
referred to in my said Provisional Specification under the three heads of the
"second," "fourth," and "remaining parts," and I therefore make no claim herein
in respect to such parts, but I would have it to be understood that I claim in respect
of the parts of my Invention included herein,―
First. The combination of parts arranged and acting substantially as set forth
and indicated herein-before, and by the Drawings in the accompanying Sheet 1.
Secondly. Admitting pressure resulting from the firing into a chamber at about
the end of the stroke of the piston, and closing the connection of such chamber with
the firing end of the cylinder before the exhaust port is opened, substantially as and
for the purpose set forth and indicated.
Thirdly. The combination of parts arranged and acting, substantially as and for

page_text: the purpose set forth and indicated hereinbefore, and by the Drawings in the
accompanying Sheet 2.
Fourthly. Conveying pressure remaining at or near the termination of the stroke
of the piston into a supplementary cylinder to act upon a second piston, substantially
as set forth and indicated.
Fifthly. Conveying the said pressure into a storage reservoir, substantially as
and for the purpose set forth and indicated when referring to Figs. 5 and 6 of the
accompanying Drawings.
Sixthly. The combination of parts arranged and acting, substantially as and for
the purpose set forth and indicated hereinbefore, and by the Drawings in the
accompanying Sheet 3.
Seventhly. The firing chamber E into which air is compressed by the piston
provided with a valve which opens and closes the communications with the
cylinder, and with arrangements for supplying the gas, substantially as and for the
purpose set forth and indicated.
Eighthly. Conveying gas not mixed with air in an unbroken stream into the
cylinder or firing chamber, substantially as set forth and indicated.
And, lastly. Arranging the slide valve, so that the pressure resulting from the fired
gases, tends to press the said valve upon its seat, substantially as set forth and
indicated.
In witness whereof, I, the said Richard Hallowell, have hereunto set my
hand and seal, this Tenth day of October, in the year of our Lord 1879.
Signed, sealed, and delivered this
Tenth day of October 1879, in the
presence of
EDWARD K. DUTTON,
Agent for the Patentee.
RICHARD HALLEWELL. (L.S.)