Improvements in Valve Gear for the "Clerk" and like_Type of Gas Engines, in which a Separate Air and Gas Pump is employed.
Year: 1893

page_text: COMPLETE SPECIFICATION.
Improvements in Valve Gear for the "Clerk" and like_Type of
Gas Engines, in which a Separate Air and Gas Pump is
employed.
I, FREDERICK JOHN FRYER, of 63 Vassall Road Brixton London S.W.
Engineer 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, reference being had to the accompanying drawings and to
the letters and figures marked thereon, that is to say :-
My invention relates to improvements in the valve gear of gas engines, and is
more particularly designed for use with the "Clerk" and like type of gas engines
in which a separate air and gas pump is employed."
My invention has for its object to provide means for effecting the more efficient
regulation of the admission of the gas and air, and to dispense with the governor
slides (such as Garret's governor gear) as at present used in engines of the above
mentioned type.
For the purpose of my invention, I provide a valve chest having suitable
passages therein and secured to, and in communication with, the motor cylinder and
the displacer or pump. In this chest I arrange two valves, the one admitting gas
through orifices or ports in its seating, and air through the main passage, to the
displacer or pump, the other admitting the explosive charge of gas and air, forced
out by the displacer or pump, into the compression chamber of the motor cylinder
wherein it enters without resistance, ignition then taking place in the usual manner.
These valves are operated alternately by means of cams and levers controlled by
the governor; and springs, or their equivalent, are employed to ensure the quick
return of the said valves onto their seats.
Part of the valve chest in proximity to the valve admitting the explosive charge,
is water cased.
And in order that my invention may be readily understood I will describe the
same fully with reference to the annnexed drawings, in which :-
:-
Fig. 1 is an end view of a "Clerk" gas engine provided with my improved valve
gear or regulating apparatus.
Fig. 2 is a side elevation of the rear end thereof.
Fig. 3 is a vertical section, on an enlarged scale, on the line 1, 1, of Fig. 2, of the
valve chest and valves, and
Fig. 4 is a vertical section on the line 2, 2, of Fig. 3, showing the air and gas
inlets, taken at right angles to the section in Fig. 3.
A is the compression chamber of the motor cylinder, B the displacer or pump,
and C the valve chest. This chest is secured to the said chamber and displacer in
any suitable manner, and contains the air and gas inlet valve d, the admission
valve e for controlling the flow of the explosive mixture to the compression chamber,
and the passages c', c³, c³, through which the explosive mixture is caused to pass, on
its way from the displacer or pump, to said chamber. Both these valves are, by
preference, of the mushroom type, and the chamber of valve e is, for its greater
part, surrounded by a water casing c.
is the gas supply pipe, and the air inlet. The pipe communicates with an
annular recess turned in the seat of the valve d, and conveying gas to the
orifices f¹ therein, while the air inlet c communicates directly with the annular
passage g in the chamber of said valve. By these means, when the valve d is open,
air will flow up the passage g
and will be mixed with the gas passing through the
orifices. These valves d and e are respectively operated alternately by means of

page_text: cams and on the side shaft k, and by levers and j¹, the said cams being
directly under the control of the governor, so that they can be thrown out of gear
simultaneously and thereby put both valves out of operation. The cam i actuates
and opens the valve d through the lever, and the cam j actuates and opens the
valve e through the lever, said levers being mounted in brackets 1, 1x and having
their fulcra at 1, respectively; they are likewise provided with friction
rollers, 13, bearing against their respective cams. The closing of the valve dis
effected in a rapid manner by means of a spring surrounding its stem d', and
compressed between the under part of the valve chamber and a collar or nut d³ on
the said stem. The valve e is actuated in a similar manner by its cam j and
lever, and a coiled spring e' surrounding its stem e', and compressed between
the under part of the valve chest C and collar or nut e, ensures its sudden return
to its seat.
The levers may be furnished with adjusting screws i, j, to compensate for wear
of the levers on their fulcra, as occasion may require.
In Fig. 1 the lever i¹ is shown as raising the valve d.
The operation of the various parts is properly timed so that the valve d lifts as
the piston of the displacer or pump commences its forward stroke, the valve e
remaining closed until the end of the stroke. Air is thus drawn in through the
inlet and passage 9, while gas is drawn in through the supply pipe cand
orifices, and together enter the displacer or pump through the pipe B¹, wherein
they become thoroughly mixed. When the displacer piston commences its rear-
ward stroke, the valve d closes, and the valve e opens, so that the explosive mixture
in the said displacer is forced through the pipe B1, passages c', c², c³, past the said
valve e, into the compression chamber A, wherein explosion takes place in the
well known manner. These operations are performed in the order stated, so long
as the engine is working normally, and the governor is not acting. When the
governor is in action, both valves are at rest, and consequently a vacuum is formed
in both cylinders, and directly the speed decreases the cams are thrown into action
by means of the governor and the engine takes its charge. As previously stated,
the cams are so connected with the governor (say for instance by means of a sleeve
and clutch) that they are thrown out of action simultaneously, and both valves
remain idle when the speed of the engine increases beyond that for which the
governor is set.
"
Although I have described and shown my invention as applied to a " Clerk
gas engine, it may be employed in like manner to gas engines of a similar type, or
to those in which a separate gas and air pump is used.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. Valve gear or apparatus for regulating the admission of gas and air to gas
engines, comprising a valve chest adapted to be secured to the compression
chamber of the motor cylinder and to the displacer or pump, and provided with
valves, one of which admits gas and air to the displacer or pump, the other
admitting the charge of gas and air, forced out by the piston of the displacer or
pump, to the compression chamber, and means for actuating said valves alternately,
substantially as set forth.
2. In valve gear or apparatus of the kind above claimed, the valve chest C
formed with passages c', c², c³, and provided with valves d and e, the seating of the
the valve d having gas orifices f¹ and annular passage y, through which gas and air
are simultaneously drawn into the displacer or pump, the valve e for admitting the
charge of gas and air forced out by the backward stroke of the displacer piston,
into the compression chamber of the motor cylinder through the said passages, the
water casing c partially surrounding the chamber of the valve e, and the cams i, j,
and levers,, for actuating said valves alternately, the stems of the valves

page_text: being provided with springs to ensure the quick return of these valves to their
seats, substantially as described and shown with reference to the annexed
drawings.
3. My improvements in valve gear for the "Clerk " and like type of gas engines
in which a separate air and gas pump is employed, substantially as hereinbefore
described and shown with reference to the annexed drawings.
ERNEST DE PASS,
Chartered Patent Agent,
78, Fleet Street, London, and 6, Victoria Street, Nottingham,
Agent for the Applicant.