Improvements in Valve Mechanism for Air and Gas Compressors.
Year: 1894

page_text: Date of Application, 19th Oct.. 1894
Complete Specification Left, 11th July, 1895-Accepted, 17th Aug.. 1895
PROVISIONAL SPECIFICATION.
Improvements in Valve Mechanism for Air and Gas Compressors.
We, TANGYES LIMITED, of Cornwall Works, Soho, in the County of Stafford,
Engineers, and WILLIAM JOHNSON the younger of No. 33 Beeches Road, West
Bromwich, in the County of Stafford, Mechanical Engineer, do hereby declare the
nature of this invention to be as follows:-
The said invention has reference principally to valve mechanism for air
compressors or machines for compressing air for use as a motive power; but the
said invention is also applicable to compressors for compressing air and gases for
other purposes.
We will describe the said invention in connection with an air compressor in which
the axis of the compressing cylinder is horizontal.
In order that the said invention may be the better understood we remark that
the object of the said invention is to permit of the passage of the compressed air
from the compressing cylinder without obstruction from the valve proper which is
actuated independently of the pressure of the compressed air; the said valve proper
being lifted from its seat and rapidly removed so far as practically to offer no
obstruction to the current of compressed air.
The port of the cylinder, which together with the greater part of the appliances
by which the valve is actuated is contained within a valve box, is situated in a
horizontal plane. The lid of the valve or valve proper is carried by an arm which
turns upon a centre situated at a lower level than the port and at a somewhat greater
distance from the end of the compressing cylinder than the said port; so that when
the said arm turns upon its centre in a direction proper for the opening of the
valve the lid or valve proper in rising from its seat describes a curvilinear path,
that is to say, it rises from its seat and at the same time retires from over its seat,
thus leaving the passage in the valve seat practically clear.
:
The arm carrying the valve proper is so weighted that the valve proper tends to
rise from its seat when at liberty to move. The valve is preferably actuated by
the eccentric of the motor engine by which the piston of the compressor is worked.
An axis to which a two-and-fro motion is communicated by the said eccentric
passes through the valve box and carries an arm or cam which when in its highest
position bears against the arm carrying the valve proper and holds it firmly on its
seat. When the said cam descends it ceases to bear against the arm carrying the
valve proper and strikes against the weighted arm of the valve. The valve is thus
liberated from its seat and by the action of gravity and the blow of the cam is
rapidly raised from and removed to its greatest distance from the valve seat.
The mechanism described is so arranged that the opening of the valve takes place
at the time when the piston of the compressor has so far advanced in the cylinder
that the air compressed is at or about the same pressure so that which has passed
the valve. The power required to open the valve is thereby reduced to a
minimum.
As the compressing piston is about to start on its return stroke the cam described
rises and restores the valve to the valve seat and supports it there until the next
advance stroke of the compressing piston has reached the point herein before
indicated.
The ingress valve of the compressor cylinder may be of the same construction

page_text: generally as the exit valve already described or it may consist of a flap valve
opened by the exhaust in the compressing cylinder and closed by a coiled or other
spring.
Although we prefer to actuate the valve mechanism by an eccentric on the steam
engine shaft yet other equivalent gearing may be employed to connect the said
mechanism with the motor engine.
Instead of the face of the valve seat and the face of the valve being arranged
horizontally as described, they may be situated vertically with nearly the same
effect.
Dated this 19th day of October 1894.
W. T. WHITEMAN,
Agent for the Applicants.
Improvements in Valve Mechanism for Air and Gas Compressors.
We, TANGYES LIMITED, of Cornwall 'Works, Soho, in the County of Stafford
Engineers, and WILLIAM JOHNSON, the younger, of No. 33 Beeches Road, West
Bromwich in the County of Stafford, Mechanical Engineer do hereby declare the
nature of the said invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
The said invention has reference principally to valve mechanism for air
compressors or machines for compressing air for use
as ta motive power; but
the said invention is also applicable to compressors for compressing air and gases
for other purposes such for example as, the compressed gas reservoirs or cylinders
used for lighting railway carriages, tramcars, and the like.
We will describe the said anvention in connection with an air compressor in
which the axis of the compressing cylinder is horizontal.
In order that the said invention may be the better understood we remark that
the object of the said invention is to permit of the passage of the compressed air
from the compressing cylinder without obstruction from the valve proper, the said
valve proper being lifted from its seat and rapidly removed so far as practically to
offer no obstruction to the current of compressed air.
The port of the cylinder, which together with the greater part of the appliances
by which the valve is actuated is contained within a valve box, is situated in a
horizontal plane. The lid of the valve or valve proper is carried by an arm which
turns upon a centre situated at a lower level than the port and at a somewhat
greater distance from the end of the compressing cylinder than the port, so that
when the said arm turns upon its centre in a direction proper for the opening of the
valve the lid or valve proper in rising from its seat describes a curvilinear path,
that is to say, it rises from its seat and at the same time retires from over its seat,
thus leaving the passage in the valve sent practically clear.
The arm carrying the valve proper is so weighted that the valve proper tends to
rise from its scat when at liberty to move. The valve is preferably actuated by
the eccentric of the motor engine by which the piston of the compressor is worked.
An axis to which a to-and-fro motion is communicated by the said eccentric passes
through the valve box and carries an arm or cam which when in its highest position
bears against the arm carrying the valve proper and holds it firmly on its seat.
When the said cam descends it ceases to bear against the arm carrying the valve
proper and strikes against the weighted arm of the valve. The valve is thus
liberated from its seat and by the action of gravity and the blow of the cam is
rapidly raised from and removed to its greatest distance from the valve seat.
The mechanism described is so arranged that the opening of the valve takes
place at the time when the piston of the compressor has so far advanced in the

page_text: cylinder that the air compressed is at or about the same pressure as that which has
passed the valve. The power required to open the valve is thereby reduced to a
minimum.
As the compressing piston is about to start on its return stroke the cam.
described rises and restores the valve to the valve seat and supports it there
until the next advance stroke of the compressing piston has reached the point
hereinbefore indicated.
The ingress valve of the compressor cylinder may be of the same construction
generally as the exit valve already described; or it may consist of a flat valve
opened by the exhaust in the compressing cylinder and closed by a coiled or other
spring.
Figure 1 of the accompanying drawings represents a portion of the cylinder of
an air compressor and one of its valve boxes with which is combined our improved
valve mechanism, the upper half of the said Figure 1 being in longitudinal vertical
section and the lower half in side elevation.
Figure 2 represents the cylinder of an air compressor the valve mechanism of
which is constructed according to a modification of the said invention the valve
box and part of the cylinder at one end being in side elevation and the valve box
and part of the cylinder at the other end being in longitudinal vertical section;
Figure 3 is an end elevation of Figure 2 part of the valve box cover being
removed.
Figure 4 represents a modification in the method of operating the valve.
Figure 5 represents one of the valve boxes of an air compressor the ingress valve
of which is constructed according to the said invention.
The same letters of reference indicate the same parts in the several figures of
the drawings.
We will first describe principally the arrangement Figure 1.
A is the cylinder of the air compressor and B is the piston of the same;
C, C are the valve boxes situated one at each end of the cylinder (see Figure 2).
a is the exit port of the cylinder and is the valve lid or valve proper by which
the port a is at the proper times opened and closed. The said valve b is carried by
the nearly vertical arm & turning on the shaft or axis c, the sleeve or boss 63 of the
said arm 6 also having the weighted arm and heel or stop 6. The valve is
operated by means of a cam like arm d fixed to the shaft or axis e which passes
through the side of and crosses the valve box C. The said shatte has an angular
motion in a backward and forward direction communicated to it, by an eccentric
on the motor shaft, through the connecting rod, and arm g on the outer end of
the shaft e (see Figures 2 and 3). When the cam like arın d moves in one
direction it turns the arm & and moves the valve over the port a thereby closing
the valve as represented in Figure 1. When the cam like arm d is turned in the
cpposite direction it liberates the valve and strikes the weighted arm by
the falling of which the arm 6 is turned and the valve by its curvilinear motion
rises and retires from over the port a as indicated in dotted lines in Figure 1. It
will be seen by an examination of Figure 1 that the valve lid b makes an angle
somewhat greater than a right angle with the jointed arm & carrying it so that on
the turning of the said arm 6' not only is the valve braised but it is moved clear of
the valve seat as indicated in dotted lines in Figure 1 and leaves the passage
for the compressed air within the cylinder practically unobstructed.
The parts of the mechanism are so arranged and operated that the valve b is
opened when the air within the cylinder is at the same or nearly the same pressure.
as the air on the outer side of the valve. Consequently the work of opening the
valve is reduced to a minimum.
We will now describe the modification Figures 2 and 3.
In this arrangement we dispense with the weighted arm for effecting the opening
of the valve, the said valve being opened when the cam has retired from off and
liberated the arm, by the pressure of the air within the upper part of the valve
box in the manner hereinafter described.

page_text: In order to effect this we secure to the cover C2 of the upper half of the valve
hox a small cylinder i provided with a piston k. The said cylinder i is nearly
closed at its outer end the small opening at the nearly closed end being regulated
by means of the screw so as to permit a small stream or jet of air to escape from
the cylinder when the piston k is forced back. The outer end of the piston k has
in its underside a catch like recess which engages with a rib or projection on
the upper end of the arm of the valve b. The pressure within the exit port side
of the valve box always tends to force the piston k within its cylinder i so that as
soon as the cam d' is turned by the connecting rod ff from off the arm & the said
piston entering its cylinder i moves the valve from off its seat in the manner
herein before described with respect to Figure 1. In this arrangement the motion
of the cam is not simultaneous with that of the eccentric on the motor shaft the
said cam coming to the end of its angular motion before the eccentric and
connecting rod have finished their motion. In order to take up the motion of the
eccentric when the cam d' has come to rest and to effect the opening and closing of
the valve at the proper times a spring box is arranged between the fore end 72
and rear end of the connecting rod. On the return motion of the piston B the
motion of the connecting rod, being reversed the cam d¹ is turned in an
opposite direction to that which permitted the valve ↳ to open and thereby effects
the closing of the said valve b.
In the arrangement Figure 4 the connecting rod is geared directly by means of
the army to the shaft c of the valve and the use of a cam like arm or cam and
mechanism connected therewith is dispensed with. This arrangement necessitates
the use of two connecting rods marked respectively f, f and f, fs, the connecting
rod f,f operating the valve at one end of the air compressor cylinder A and the
connecting rod f,f operating the valve at the other end of the said air compressor
cylinder A. In other respects the arrangement Figure 4 is the same as that
hereinbefore described and corresponding parts are marked with the same letters of
reference.
In Figures 2 and 3 I have represented the ingress valve 1 of the ordinary
construction the said valve being operated in the ordinary way but the said ingress
valve may be constructed according to the said invention as represented in Figure 5
and marked and worked in either of the several ways hereinbefore described with
respect to the egress valve.
Although we prefer to actuate the valve mechanism by an eccentric on the steam
engine shaft yet other equivalent gearing may be employed to connect the said
mechanism with the motor engine.
The improvements in the valve mechanism of air compressors hereinbefore
described are equally applicable to the valve mechanism of gas compressors.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that we claim
as the said invention of " Improvements in valve mechanism for air and gas
compressors";—
First. The improvements in the ingress and egress or exit valves of the valve
mechanism of air and gas compressors herein before described and illustrated in the
accompanying drawings; that is to say, arranging the lid of the valve or valve
proper, carried by a jointed arm, and the valve seat for the said valve preferably at
an angle somewhat greater than a right angle with the said jointed arm so that
when the valve arm is turned for lifting the lid or valve proper the said lid retires
from over its valve seat so as to leave the passage for the gas or air escaping by or
passing through the open port unobstructed substantially as hereinbefore described
and illustrated.
Secondly. The combination with a valve of the kind hereinbefore described and
represented and claimed in Claim 1 of the weighted arm and cam like arm d
herein before described and represented in Figure 1 of the accompanying drawings
for effecting the opening and closing of the said valve, the said cam like arm d

page_text: having a rocking or backward and forward motion communicated to it by an
eccentric on the motor shaft or other equivalent mechanism substantially as herein-
before described.
Thirdly. The combination with a valve of the kind herein before described and
represented and claimed in Claim 1 of a cam d¹ and small cylinder i with piston k
on the valve box cover C³ the said piston k engaging with a projection or rib on
the jointed arm of the valve substantially as and for the purpose herein before
described and represented in Figures 2 and 3 of the accompanying drawings.
Dated the Tenth day of July 1895.
TANGYES LIMITED,
W. J. PARKINS, Secretary.
WILLIAM JOHNSON, JUNK.