Compras, DIVINGgines, and like Machinery.
Year: 1888

page_text: Compras, DIVINGgines, and like Machinery.
A communication from abroad by EDWIN REYNOLDS, of Milwaukee, Wisconsin,
United States of America, Mechanical Engineer.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool and, 6, Bank Street, Manchester, both in
the County of Lancaster, and 323, High Holborn in the County of Middlesex, Civil
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:-
This invention relates to certain improvements in valve mechanism of air com-
pressors, blowing engines and like machinery, whereby the action of the delivery
valve is rendered automatic, and its time of opening is made dependent upon the
relative pressures in the air cylinder, and in the receiver or reservoir to which the
air is delivered, its time of closing being positively determined by connection with
other moving parts of the machine.
In the accompanying drawings:
Figure 1 is a side elevation of one end of an air cylinder of an air compressor,
showing the improved valve mechanism, the ports and gates being indicated in
dotted lines.
Figure 2 an end elevation of the same.
Figures 3 and 4 views illustrating the construction and operation of the delivery
valve.
Heretofore, flap valves and poppet valves have been employed in air compressors,
blowing engines, and analogous machinery, to permit and control the passage of air
from the air cylinder to the receiver or reservoir, and such valves are automatic in so
far as they open when the pressure of air in the cylinder exceeds that in the receiver
sufficiently to overcome the latter, the weight of the valves and the additional pressure
of the springs or weights employed to return the valves to their seats, but the action
of such valves is uncertain and noisy, and their use involves the expenditure of power

page_text: over and above that actually necessary, to the amount required to raise the pressure
in the cylinder sufficiently above that in the receiver to overcome the resistance of the
weight of the valves, and the resistance of their springs.
The use of such valves also limits the working speed of the machine.
Slide valves, and oscillating or rolling valves have also been employed heretofore as
delivery valves for this class of machines; but in such cases the action of the valves
has been positively determined by connection with other moving parts of the machine,
so that the time of their opening has had no reference to the relative pressures in the
air cylinder and receiver except as determined by positive adjustment of the operating
mechanism, the delivery valve opening either before or after the pressure in the
cylinder equalled the pressure in the receiver, the receiver pressure varying above or
below the point at which the valve is set to open.
In either case a needless expenditure of power is involved and the efficiency of the
machine is limited to certain fixed conditions and requirements, thus making it
impossible for any given machine to operate with a satisfactory degree of economy or
efficiency except under the precise and fixed conditions for which that particular
machine was originally designed.
In the various forms of valve mechanism heretofore employed for this class, of
machines there has also been an excessive amount of clearance in the air cylinder,
resulting in waste of power.
By this invention these difficulties and defects are obviated and the clearance space
is reduced to a minimum. The delivery valve is so constructed and arranged as to
open automatically and instantaneously, its full capacity when the pressure in the
air cylinder is nearly or quite equal to that in the receiver. The point of relative
pressures at which the opening of the valve shall take place may be determined in
constructing the machine, or by very simple means may be varied at any time
desired.
The invention is susceptible of embodiment in different forms, the annexed drawings
and the following description disclosing the construction and arrangement which is
considered most advisable.
In said drawings, A indicates the air cylinder and B the head thereof, containing
In this head are
the valve chambers for one inlet valve C, and one delivery valve D.
also formed the usual passages to admit air to the inlet valve, and to connect the
delivery valve chest with the receiver.
Suitable port openings indicated by dotted lines are provided between the valve
chambers and the interior of the cylinder, which ports are opened and closed by the
valves at the proper times, as herein explained.
The valve seats are brought as close as possible to the inner face of the head B,
thus reducing the clearance space to the smallest practicable amount.
The valves C and D are made preferably of the rolling or oscillating type, though
my correspondent does not mean to be understood as confining himself thereto, it
being apparent that any one of a large variety of types may be selected and used in
carrying out the invention.
Motion is communicated to valves C and D, preferably by means of a wrist
plate W, and connecting rods R, R', the rods connecting with suitable arms fastened
to the valve stems, as plainly shown in Figure 1. The wrist plate receives motion
from an eccentric on the main shaft of the machine through suitable connection, or
may be actuated in any other convenient manner.
When a wrist plate is employed it is carried by a stand or an arm bolted to the side
of the cylinder. The connection between wrist plate W and inlet valve C is at all
times positive, and any motion of the wrist plate imparts corresponding motion to the
inlet valve. The action of inlet valve C is therefore simply that of any ordinary rolling
slide valve, the times of opening and closing being controlled by the well known
action of the wrist plate.
The connection between the wrist plate W and the delivery valve D is made by
means of a rod: R', slotted or forked to receive the pin a of the actuating arm of the
valve, and is positive only at such time as the rod It', is moving toward the cylinder

page_text: head and acting upon the valve to close it. When the motion of the wrist plate is
reversed the slotted or forked end of rod R' permits the reverse motion of the wrist
plate and rod R¹ to take place while the delivery valve remains closed and is held in
position by a hook or catch L, until such time as it is automatically released and
allowed to open.
The mechanism by which delivery valve D is held closed until the proper moment,
and then automatically released and permited to open, is more clearly illustrated in
Figures 3 and 4.
As shown in said Figures and also in Figure 1, an arm E is keyed on or otherwise
attached to the stem of valve D, said arm at or near its outer end carrying a pin F
and a block G. To said arm E is also attached by suitable pin and rod, a weight H,
working in a dash pot I.
J indicates a fixed pin, on which is pivoted the book or catch L, above referred to,
which book is provided with a tail piece M, and is pressed downward by a spring N,
whereby the hook L is pressed forward and caused to engage with block G.
O indicates a small supplemental cylinder, provided with a piston P and piston
rod S, said rod reaching nearly to tail piece M of hook L when the delivery valve
is closed and held closed by the hook; the piston rod being of such length that a
short movement of the piston P will cause it to bear against tail piece M, and that a
further movement of said piston will cause tail piece M and hook L to move and
release the valve, which is then instantaneously opened to its full extent by the falling
weight H.
A pipe T connects one end of cylinder O with the receiver, and a similar pipe U
connects the other end of said cylinder with the end of air cylinder A, so that on one
side of piston P there is always the pressure of the air in the receiver, and on the
other side there is whatever pressure may be in the air cylinder.
The action of the mechanism is as follows:-
As the wrist plate W and rod R¹ move toward head B, the delivery valve D is
closed positively, and as the extreme limit of motion of the wrist plate is reached,
hook L is thrown forward by spring N, engages with block G and holds the valve
closed, as shown in Figure 3. As the motion of wrist plate W and rod R¹ is reversed.
the forked end of said rod slides back upon and independently of the pin a, and
consequently allows the delivery valvo D to remain closed until such time as the
pressure in the air cylinder and consequent pressure on the side of piston P connected
with the air cylinder by pipe U, is sufficient to overcome the pressure on the opposite
side of piston P connected with the receiver by pipe T, when piston P will movo, and
carry with it the rod S, causing the latter to strike against the tail piece M and to
move it, thereby disengaging hook L from block G.
When this disengagement takes place, the action of weight H simultaneously
opens delivery valve D to its full extent, as shown in Figure 4, and it remains thus
open until again closed by the action of wrist plate W and rod R¹.
.
The complete action of the valves on one end of the air cylinder may be briefly
described as follows:
At the beginning of the stroke the piston in the air cylinder A is at the end closed
by head B, and just beginning to move toward the opposite end of the cylinder. At
the same time the delivery valve is closed and the inlet valve commences to open,
opens very quickly, and remains open until the piston reaches the opposite end of its
stroke. Just as the piston begins its return stroke the inlet valve is closed, and it is
retained against its seat by the receiver pressure on its back. As the piston in air
cylinder A moves toward head B, the air before it is compressed, until it equals the
pressure in the receiver, when the movement of piston P in the small supplemental
cylinder O disengages the retaining hook L and allows delivery valve D to be opened
by the action of the weight.
At the time of its opening the delivery valve is in equilibrium, so that the amount
of power required to close it is very small.
It is obvious that a vacuum dasli pot may be employed instead of a weight to close
the valve, such construction being the same as represented in Figure 1 except that

page_text: the piston or plunger of the dash pot will be lighter and more closely fitted, and that
the openings represented in the bottom of the dash pot, will be omitted.
When the delivery valve is open it offers no resistance to the passage of the air
from the air cylinder into the receiver and hence imposes no additional work on the
motive power.
In building the machine, the precise point of relative pressure in the receiver and
air cylinder at which the delivery valve shall open, may be determined and fixed by
the cross section or area given the rod S of piston P, it being apparent that as its
diameter is increased the effective arca of that face of piston P with which it connects
will be decreased, and that to such extent the opposite face will be greater in pressure
area, hence the pressure on such opposite face will exceed in a greater or less degree
the pressure on the face from which rod S projects, and consequently the delivery
valve will open just a little before the pressures in the air cylinder and receiver are
equalized.
The same result may be attained by making the piston P in two sections of different
diameter, and the relative areas may, if desired, be reversed so that the valve shall
open only when the cylinder pressure slightly exceeds the receiver pressure.
In order to permit the control and variation of the point of relative pressures at
which the delivery valve shall open, a spring or weight may be applied to offer a
greater or less resistance to the movement of the piston toward or against_tail Mof
latch L. If spring pressure be employed for this purpose the spring N may be
utilized and other spring or springs rendered unnecessary, a set screw Q being
arranged to bear upon and vary the force of the spring as indicated in Figure 4.
If a weight be employed, it may be conveniently applied to an extension of tail M,
and made adjustable thereon, as shown in Figure 3 in dotted lines.
Under both these arrangements, with the piston area slightly in favor of the air
cylinder pressure, it is possible to vary the point of opening so that it shall be, when
the two pressures are exactly equal, or when the cylinder is slightly below or slightly
above the receiver pressure, a range adequate for all conditions that can arise in the
use of such machinery; but obviously the range may be increased as desired.
before stated, the details of construction are susceptible of considerable variation, and
therefore my correspondent does not restrict himself to the precise form or arrange-
ment of parts shown.
As
The weight H for opening valve D may obviously be replaced by a spring, though
the weight is preferred.
In other words, the only thing essential is that the valve shall be self opening, or
capable of opening automatically when released by the catch, instead of being moved
through connection with other moving parts of the machinery, or by fluid pressure.
It is likewise apparent that a flexible diaphragm may be used instead of the sliding
piston P, the two being well recognized equivalents for such uses, and that instead of
being slotted to straddle pin a, the rod R' may pass through the same, in which case
the pin would need to be swivelled in the valve arm. The construction shown and
described is, however, preferred.
Having now particularly described and ascertained the nature of the said invention,
and in what manner the same is to be performed, as communicated to me by my
foreign correspondent, I declare that what I claim is :-
1. In an air compressor, blowing engine or like machine, the combination of a
self-opening delivery valve, a rod having a sliding connection with said valve, and
serving when moved in one direction, to close the same, a catch adapted to hold the
valve closed, and a movable stem or trip subject to the opposing pressures of the fluid
in the receiver and in the compressor, and arranged to act upon the catch, whereby
the catch is caused to hold the delivery valve closed, until the trip is moved by tho
pressure of the fluid in the compressor overcoming the pressure or resistance of the
fluid in the receiver, and then to release the valve, thereby permitting the latter to open.
2. In combination with the delivery valve of an air compressor, blowing engine or
like machine, a connecting device between said valve and a moving part of the

page_text: machine, for closing the valve, a catch or hook for holding said valve closed, a weight
or spring for opening said valve when released by the catch, and a trip controlled by
the pressures in the air cylinder and in the receiver, for releasing the catch, whereby
the delivery valve is released and opened when a certain predetermined relation is
established between the receiver and cylinder pressures.
3. In an air compressor, blowing engine, or like machine, the combination of
self-opening delivery valve, a catch for holding said valve closed, a rod or connection
extending from a moving part of the machine to the valve and serving to close the
latter, a cylinder communicating at opposite ends with the air cylinder and the
receiver, and a piston arranged within said cylinder and serving to release the catch
when the pressure on the face of the piston receiving air from the air cylinder
overcomes the pressure on the face receiving air from the receiver.
4. In combination with the delivery valve of an air compressor, blowing engine, or
like machine, a catch adapted to engage said valve and hold it closed, and a trip for
releasing said catch, actuated and controlled by the relative pressures in the air
cylinder and in the receiver.
5. In combination with the delivery valve of an air compressor, blowing engine, or
like machine, a catch adapted to engage and hold said valve out of action, a trip for
releasing said catch, actuated and controlled by the relative pressures in the air
cylinder and in the receiver, and an adjustable resistance for varying the point of
relative pressures at which the trip shall release the catch.
6. In combination with air cylinder A, head B provided with valve chambers, inlet
valve C, delivery valve D, wrist plate W, rod R connecting valve C with the wrist
plate, slotted rod R', connecting valve D, and the wrist plate, arm E attached to stem
of valve D and provided with block G, hook or catch Ĺ provided with tail M,
cylinder O, piston P arranged within said cylinder, rod S extending from the piston
to a point just beneath tail M, and pipes T and U respectively connecting opposite
ends of cylinder O with the air receiver and the air cylinder.
7. In an air compressor, blowing engine, or like machine, the combination of a
delivery valve provided with a weighted arm and with a projecting block or lug,
a pivoted catch adapted and arranged to engage with said lug and to hold the valve
closed, a cylinder communicating at its opposite ends with the air receiver and air
cylinder, and a piston located within said cylinder and serving to release the catch
when the pressure from the air cylinder reaches a prescribed relation to that from the "
receiver..
8. In an air compressor, blowing engine, or like machine, the combination with the
delivery valve D, of two arms rigidly attached to its stem, a pin a carried by one of
said arms, a slotted rod connected with a moving part of the machine and straddling
said pin, a pivoted catch L adapted to engage with the second arm and provided with
a tail M, a spring N bearing upon said tail, cylinder 0 communicating at opposite
ends respectively, with the air receiver and the air cylinder, piston P within said
cylinder, and rod S extending from said piston to a point just beneath tail M when
the valve is closed.
9. In combination with valve D, catch hook L and tripping devices therefor
constructed and arranged to operate as set forth, a variable depressing devico applied
to the tail of said latch, for the purpose explained.
10. In combination with valve 1) and its described tripping mechanism, spring N
and set screw bearing upon said spring and serving to vary the resistance of the
catch to the force exerted by the piston of the tripping mechanism.
Dated 4- 304 10 uu
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Agents for the Applicant.