IMPROVEMENTS IN VALVES FOR GAS ENGINES
Year: 1878

page_text: LETTERS PATENT to John Cropper and Williain, Johnson, both of the Town and
County of the Town of Nottingham, for the Invention of "IMPROVEMENTS IN
VALVES FOR GAS ENGINES."
Sealed the 25th February 1879, and dated the 30th August 1878.
PROVISIONAL SPECIFICATION left by the said John Cropper and William
Johnson at the Office of the Commissioners of Patents on the 30th August
1878.
JOHN CROPPER and WILLIAM JOHNSON, both of the Town and County of the
Town of Nottingham. "IMPROVEMENTS IN VALVES FOR GAS ENGINES."
The Invention has for its object improvements in valves for gas engines.
For this purpose, according to one arrangement, we form each valve of a circular
plug fitting a barrel or chamber open on the one side to the port of the cylinder
and on the other to the supply of gas and air.
For a feed valve we forin the plug hollow, and we form a passage around the
plug for a suitable distance, leaving a cylindrical shell between such passage and the
interior space of the plug. On one side of this passage is a solid portion fitting
closely the interior of the barrel or chamber in which the plug works, and on the
other side is a shell, also fitting the barrel, and between which and the interior shell
of the plug the aforesaid passage is continued to a suitable opening on the surface of
the plug. Through the solid portion of the plug a passage is formed which commu-
nicates with the space or chamber in the interior of the plug, and serves to permit a gas
jet in the said interior space to ignite at the proper time the charge in the cylinder
or chamber in which the explosion takes place. The ends of this interior space are
provided with suitable covers and valves to enable them to be entirely closed at the
moment of explosion and whilst the expanded gas is propelling the cylinder, but
these end valves are opened at the proper time to supply air to the igniting gas jet
and thereby keep it alight or if it should have become extinguished, to enable the
same to be re-lighted by a gas jet on the exterior of the plug. A groove, chase, or
"

page_text: recess is formed in the interior face of the barrel communicating with the passage
into the cylinder and extending a certain distance around the plug, and communi-
cating with the annular passage therein, to cause at the moment of explosion and
during the expansion of the exploded gas an equilibrium on the valve, and assist
in maintaining the same tight.
The exhaust valve may be formed similar to the above except that the interior
chamber may be dispensed with, or the ends thereof may be permanently closed,
whilst there is no necessity for the passage from the interior to the exterior of the
plug. These valves are worked together in pairs, one for each end of the cylinder, and
have only a slight amount of rotary motion imparted thereto, which is given thereto
as quickly as possible, and they remain stationary for a considerable period. Or
the exhaust valve may be made to act as a slide valve, in which case the valve seat
is formed on the under face of the valve cover, and two or more openings are formed
in or near each end of the valve cover, which openings communicate with the
exhaust pipe. The valve is formed with one or more slits or openings near the end
corresponding in dimensions with the openings in the valve seat, so as to enable all the
said openings to be covered and uncovered with a slight amount of motion to the valve.
These valves are worked together in pairs, and are connected to flat springs fixed to
a bar working on the back of the valve cover, and this bar is worked by a suitable
connection from the engine. The springs assist to keep the valves up to their seats,
whilst at the moment of explosion and during the expansion of the gas they are
held firmly to their seats by the pressure in the cylinder. Motion is given to these
valves at the time when the pressure in the cylinder from the exploded gas las
become reduced to its lowest point, and they remain stationary whilst the pressure
is, on them, thereby enabling the valve to be easily moved without requiring much
power to be applied thereto..
By the construction of valves herein described we are relieved of the necessity
of using heavy springs as heretofore for the purpose of keeping the valves up to
their seats, and consequently friction is greatly reduced, by giving motion thereto
during only a small portion of the motion of the piston, and allowing them to remain
stationary during a considerable period, combined with the peculiar construction
thereof, the power required to operate them is further reduced and the passages
are more quickly opened and closed than in valves formed in the manner heretofore
adopted.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Cropper and William Johnson in the Great Seal Patent Office
on the 28th February 1879.
JOHN CROPPER and WILLIAM JOHNSON, both of the Town and County of thẹ
Town of Nottingham. "IMPROVEMENTS IN VALVES FOR GAS ENGINES."
The Invention has for its object improvements in valves for gas engines.
For this purpose, according to one arrangement, we forin each valve of a circular
plug fitting a barrel or chamber open on the one side to the port of the cylinder
and on the other to the supply of gas and air.
For a feed valve we form the plug hollow, and we form a passage around the plug
for a suitable distance, leaving a cylindrical shell between such passage and the
interior space of the plug. On one side of this passage is a solid portion fitting
closely the interior of the barrel or chamber in which the plug works, and on the
other side is a shell, also fitting the barrel, and between which and the interior shell
of the plug the aforesaid passage is continued to a suitable opening on the surface of
the plug. Through the solid portion of the plug a passage is formed which communi-
cates with the space or chamber in the interior of the plug, and serves to permit a gas
jet in the said interior space to ignite at the proper time the charge in the cylinder
or chamber in which the explosion takes place. The ends of this interior space are
provided with suitable covers and valves to enable them to be entirely closed at the
moment of explosion, and whilst the expanded gas is propelling the piston, but
these end valves are opened at the proper time to supply air to the igniting gas jet;
and thereby keep it alight, or if it should have become extinguished, to enable the
same to be re-lighted by a gas jet on the exterior of the plug. A groove, chase, or
recess is formed in the interior face of the barrel communicating with the passage
into the cylinder and extending a certain distance around the plug, and communi-
cating with the annular passage therein; to cause at the moment of explosion and
during the expansion of the exploded gas an equilibrium on the valve, and assist in
maintaining the same tight.
The exhaust valve may be formed similar to the above except that. the interior
chamber may be dispensed with, or the ends thereof may be permanently closed,
whilst there is no necessity for the passage from the interior to the.exterior of the
plug.
These valves are worked together in pairs, one for each end of the cylinder, and
have only a slight amount of rotary motion imparted thereto, which is given thereto
as quickly as possible, and they remain stationary for a considerable period:
Or the exhaust valve may be made to act as a slide valve, in which case the valve
seat is formed on the under face of the valve cover, and two or more openings are
formed in or near each end of the valve cover,, which openings communicate with
the exhaust pipe. The valve is formed with one or more slits or openings near the
end corresponding in dimensions with the openings in the valve seat, so as to
enable all the said openings to be covered and uncovered with a slight amount
of motion to the valve. These valves are worked together in pairs, and are connected
to flat springs fixed to a bar working on the back of the valve cover, and this bar is
worked by a suitable connection from the engine. The springs assist to keep the
valves up to their seats, whilst at the moment of explosion and during the expan'
sion of the gas they are held firmly to their seats by the pressure in the cylinder.
Motion is given to these valves at the time when the pressure in the cylinder from
the exploded gas has become reduced to its lowest point, and they remain stationary
whilst the pressure is on them, thereby enabling the valve to be easily moved
without requiring much power to be applied thereto.
By the construction of valves herein described we.are relieved of the necessity of
using heavy springs as heretofore for the purpose of keeping the valves up to their
seats, and consequently friction is greatly reduced, whilst by giving motion thereto

page_text: during a small portion of the motion of the piston, and allowing them to remain
stationary during a considerable period, combined with the peculiar construction
thereof, the power required to operate them is further reduced, and the passages
are more quickly opened and closed than in valves formed in the manner heretofore
adopted.
And in order that our said Invention may be more clearly understood and
readily carried into effect, we will proceed, aided by the accompanying Drawings,
more fully to describe the same.
A
•
:
Figure 1 is a side elevation, Figure 2 is a plan, and Figure 3 is a cross section on
the line 1, 1, of Figure 2 of parts of a gas engine provided with feed and exhaust
valves constructed and arranged according to our Invention, and Figure 4 is a face
view separately of one of the cams shown in the previous Figures.
Figure 5 is a plan, Figure 6 is a longitudinal section, and Figure 7 is a cross
section on the line 2, 2, of Figure 6 of the exhaust valves shown at Figures 1, 2,
and 3. Figure 8 is a cross section on the line 3, 3, of Figure 9, and the latter is a side
view separately of one of the feed valves shown in Figures 1, 2, 3; and Figure 10
is a cross section showing a modification in the construction of feed valve.
Figure 11 is a section and Figure 12 is a side view of a cylinder provided with
rotary exhaust valves as well as rotary feed valves according to our Invention.
Figures 5, 6, and 7, are drawn half full size, and Figures 8, 9, and 10, aro drawn full
size of the parts.
Figure 13 is a side view; Figure 14 is a cross section on the line 4, 4, of
Figure 13, and Figure 15 is an end view of another modified form of rotary feed
valve.
Similar parts are marked with corresponding letters of reference in all the
Figures.
A represents the bed plate or framing of the engine.; B, the cylinder; and C, the
crank shaft; a, a, represent rotary feed valves, and b, b, exhaust valves, which
-latter, as represented at Figures 1 to 7 inclusive, are arranged to move like slide
valves.
:
A convenient mode of giving motion to the valves is represented at Figures
1, 2, 3, in which E represents a shaft or axle, which receives rotary motion from
the crank shaft C through the intermediate shaft D, bevelled toothed wheels C¹, D¹,
D, and E. On this shaft or axle E are fixed a cam E for giving motion to the
feed valves, and a cam E³, shown separately at Figure 4, for giving motion to the
exhaust valves.
The cam E acts upon trucks or rollers carried by levers F, each of which is
mounted on an axis of motion at F', and is pin-jointed at F to a link F³, which
is pin-jointed to an arm or lever F' fixed to the axis a¹ of one of the valves a, a,
The cam E acts upon a truck or roller carried at the lower end of a lever G, which
is mounted on an axis of motion at G¹, and is connected at its upper end by
a link G2 to a stud projecting from a plate or bar 63 connected to and operating
the exhaust valves b, b.
We would here remark that other means of operating these valves may be
employed so long as they are correctly timed and operated, so as to leave them at
rest whilst the pressure of the exploded gases is acting on them, and change their
position when such pressure ceases or is reduced to its lowest point.
The feed valves a, a, are each formed of two circular. discs a¹, a¹, connected to
each other by means of an outer shell a² and an inner shell a³. The said inner and
outer shell form a chamber a, and a slot or port a communicating with such
chamber a is made in the periphery or outer shell a². In the chamber a* opposite
the port or slot as is provided a gas jet a, which is supplied with gas by a hole or
passage formed in the lower end or disc a', and communicating with a slot or

page_text: recess a formed on the periphery of such disc, which slota, see Figure 13, commu-
nicates with a hole passing through the valve case-c; into which the gas pipe as is
fixed. Thus in the motion of the feed valves a the supply of gas to the jet a
continues, whilst any portion of the slot a is opposite the hole leading from the
pipe as, but is cut off directly it passes such position, thereby preventing the gas
being blown back the pipe as by the explosion in the cylinder.
Around the inner chamber at is a space or annular porta, through which the
gas and air from the mixing chamber is fed into the cylinder through the ports
c, c², and such port a is provided with an outer shell or cut-off plate a to cut off
the feed or supply of gas and air from the mixing chamber d during the explosion
of the charge in the corresponding end of the cylinder.
This outer shell or cut-off plate 10 may be formed solid with the ends or discs a
of the valve a, as shown at Figures S and 9, or it may be made as a separate piece
fitting closely the.discs a¹, as shown at Figure 10, in which case it is pressed out-
wards by springs all against the valve case c.. By this construction any gas which
may find its way into the valve from the cylinder during the explosion and
expansion of the gases in the latter,, will act against such moveable cut-off, plate al
and thereby effectually close the port c
In cases where compressed air is used in combination with gas, we combine with
such moveable cut-off plate at an exterior shell or cut-off plate a12, which is held in
position on the exterior of a supplemental valve case a¹³ enclosed or partially
enclosed by the valve case or box c by springs a and studs screwed into the
plate ao, as shown at Figure 10, by which means the pressure of the compressed
air on the exterior of the cut-off plate a will keep the latter close to its seat on
the supplemental valve case a¹³. When using this last described arrangement of
valve the springs a" are unnecessary and are therefore dispensed with; In the
movement of the valves a the lighted jets a are at the proper times brought
opposite the ports c², and thereby placed in direct communication with the gas in
the cylinder to ignite it..
In Figure 11 the valves a, a, and b, b, are represented in their extreme positions,
but as the motions of such valves will be readily understood by a competent
mechanic we have not thought it necessary to give further diagrams thereof.
A permanent gas jet e is kept alight outside the port or opening in the valve
case c to re-light the inner jet a in the event of the latter being extinguished
by the explosion in the cylinder or otherwise.
In the modification represented at Figures 13, 14, 15, the port a³ is made narrower
than that shown in the previous Figures, and holes a are formed in the discs a¹ of
the valve, which at the required times communicate with corresponding holes formed
in the ends or covers a¹6 of the valve case, in order to supply air to the inner gas
jet a to support combustion. The movement of the valve a closes these holes at
the required times, and thereby cuts off the communication between the outer air
and the gas jet at the moment of explosion and during the expansion of the
gases in the cylinder.
The exhaust valves b may be formed somewhat similarly to the above-described
feed valves, as represented at Figure 11, except that no interior chamber is required,
and the ends thereof are permanently closed, whilst there is no necessity for a
passage being formed through the shell or cut-off plate b*.
The exhaust valves may, however, be formed to act as slide valves, as represented
at Figures 1 to 7, in which case the valve seat f' is formed on the under face of
the valve cover f, and two or more openings f are formed in or near each end of
the valve cover f, which communicate with the exhaust passages g, g.
Each valve b consists of a flat rectangular piece of metal, and is formed with one
or more slits or openings b¹ near one end, corresponding in dimensions with the
openings in the valve seat, so as to enable all such openings to be covered and
uncovered with only a small amount of motion to the valves. In engines wherein
gas is exploded at each end of the cylinder the valves herein described are worked
together in pairs, as shown, and the valves b are connected to flat springs b² fixed to

page_text: a bar b working on the back of the valve cover f, and are operated as before
described, or in other convenient and suitable manner, but in single-acting engines;
only one valve of each kind is required.
The springs bassist to keep the valves b in position during their traverse, whilst
at the moment of explosion and during the expansion of the gases in the cylinder
they are held firmly to their seats by the pressure of such gases.
Motion is given to all our improved valves at the time when the pressure in the
cylinder from the exploded gases has become reduced to the lowest point, and they
remain stationary whilst the pressure is on them; this, combined with the peculiar
construction and arrangement of the valves, enables us to dispense with heavy
springs for keeping the valves up to their seats, thereby greatly reducing the
friction and enabling such valves to be easily moved without requiring much power
to be applied thereto, and by giving motion to such valves during only a small
portion of the stroke of the piston, and allowing them to remain stationary during
à considerable period, the power required to operate them is further reduced and
the ports are more quickly opened and closed than is the case with valves formed,
and operated in the manner heretofore adopted.
Having thus described the nature of our said Invention, and the mode in which
we carry the same into effect, we would have it understood that we do not confine
ourselves to the precise details herein shown and described, but what we claim is,
the peculiar construction, arrangement, and mode of working of valves for gas
engines, substantially as and for the purpose herein shown and described.
In witness whereof, I, the said John Cropper, have hereunto set my hand and
seal, this Twenty-fifth day of February, in the year of our Lord One thousand
eight hundred and seventy-nine.
JOHN CROPPER. (L.S.)