Improvements in the Valves of Air and Gas Compressors.
Year: 1893

page_text: Date of Application, 26th June, 1893
Complete Specification Left, 14th Mar., 1894-Accepted, 14th Apr., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Valves of Air and Gas Compressors.
We TANGYES LIMITED of Cornwall Works, Soho, in the County of Stafford,
Engineers and THOMAS JEFFERISS, of Holyhead Road Handsworth, in the
County of Stafford, Mechanical Engineer do hereby declare the nature of this
invention to be as follows:-
In air and gas compressors as ordinarily constructed loss of efficiency and power
is occasioned by the construction of the valves by which the air or gas to be
compressed is admitted into the cylinder in which it is compressed as well as by
the valves through which the compressed air or gas is delivered and the said
improvements have for their object to prevent this loss of efficiency and power by
the construction and arrangement hereinafter described of the said valves and
appliances connected therewith.
We will describe the said invention with respect to a compressor compressing
atmospheric air.
In air compressors as ordinarily constructed the inlet valve by which the air to
be compressed enters the cylinder is made to open for the admission of air by the
effect of suction only so that the air entering the cylinder is rarefied during the
whole of the stroke of the piston. As it is desirable to obtain a full charge of air
at atmospheric pressure we maintain the inlet valve open by the means hereinafter
described until the piston is close to the end of its stroke and we effect this in the
following mauner.
We connect the inlet valve by means of a link to a piston working in a small
supplementary cylinder which cylinder is connected by a pipe to near the opposite
end of the compressor cylinder. During the first portion of the stroke of the
compressor piston the inlet valve opens by suction; but as the air in front of the
large piston is compressed a portion of it passes by means of the pipe referred to
into the small supplementary cylinder the piston of which being forced forward
maintains the inlet valve open to its full extent until near the completion of the
stroke of the compressor piston. The pipe connecting the small supplementary
cylinder with the compressor cylinder opens into the compressor cylinder on the
suction side of the piston at a point which the piston just passes on the completion
of its stroke. The supplementary cylinder which was in communication with the
compressed air in front of the compressor piston during the greater part of the
notion of the piston is thereby put into communication with the suction side of
the compressor piston and the said supplementary cylinder exhausts into the com-
pressor cylinder. The spring of the inlet valve then closes the said valve, and the
operations described are repeated.
In order to avoid the loss of efficiency and power which results by the use of the
delivery or exit valves ordinarily employed we employ a piston valve or valves for
the exit valve the piston with packing rings working with little friction in its
cylinder. When the pressure in the compressor cylinder exceeds the pressure in
the receiver plus the pressure of the spring required to carry the piston back, the
said piston will be forced forward until the ports are opened sufficiently to allow
the compressed air to pass into the receiver. On the return of the compressor
piston to take in a fresh charge of air the piston valve will be closed by its spring.
Buffers are provided for regulating the stroke of the piston valve.
Dated this 26th day of June 1893.
W. T. WHITEMAN,
Agent for the Applicants.

page_text: Improvements in the Valves of Air and Gas Compressors.
We TANCYES LIMITED, of Cornwall Works Soho in the County of Stafford
Engineers and THOMAS JEFFERISS, of Holyhead Road Handsworth 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 :-
In air and gas compressors as ordinarily constructed loss of efficiency and power
is occasioned by the construction of the valves by which the air or gas to be
compressed is admitted into the cylinder in which it is compressed as well as by the
valves through which the compressed air or gas is delivered, and the said improve-
ments have for their object to prevent this loss of efficiency and power by the
construction and arrangements hereinafter described of the said valves and
appliances connected therewith.
We will describe the said invention with respect to a compressor for compressing
atmospheric air.
In air compressors as ordinarily constructed the inlet valve by which the air to
be compressed enters the cylinder is made to open for the admission of air by the
effect of suction only so that the air entering the cylinder is rarefied during the
whole of the stroke of the piston. As it is desirable to obtain a full charge of air
at atmospheric pressure we maintain the inlet valve open by the means hereinafter
described until the piston is close to the end of its stroke and we effect this in the
following manner.
We connect the inlet valve by means of a link to a piston working in a small
supplementary cylinder which cylinder is connected by a pipe to near the opposite
end of the compressor cylinder. During the first portion of the stroke of the
compressor piston the inlet valve opens by suction but as the air in front of the
large piston is compressed a portion of it passes by means of the pipe referred to
into the small supplementary cylinder the piston of which being forced forward
maintains the inlet valve open to its full extent until near the completion of the
stroke of the compressor piston. The pipe connecting the small supplementary
cylinder with the compressor cylinder opens into the compressor cylinder on the
suction side of the piston at a point which the piston just passes on the completion
of its stroke. The supplementary cylinder which was in communication with the
compressed air in front of the compressor piston during the greater part of the
motion of the piston is thereby put into communication with the suction side of
the compressor piston and the said supplementary cylinder exhausts into the
compressor cylinder. The spring of the inlet valve then closes the said valve,
and the operations described are repeated. In order to avoid the loss of efficiency
and power which results by the use of the delivery or exit valves ordinarily
employed, we employ a piston valve or valves for the exit valve, the piston with
packing rings working with little friction in its cylinder. When the pressure in
the compressor cylinder exceeds the pressure in the receiver plus the pressure of
the spring required to carry the piston back, the said piston will be forced forward
until the ports are opened sufficiently to allow the compressed air to pass into the
receiver. On the return of the compressor piston to take in a fresh charge of air
the piston valve will be closed by its spring. Buffers are provided for cushioning
the stroke of the piston valve.
Figure 1 of the accompanying drawings represents in side elevation an air or gas
compressor containing the improvements constituting the said invention :
Figure 2 represents an elevation of a portion of the front end of the same
drawn to a larger scale;

page_text: Figure represents a portion of one of the covers of the air compressor in
vertical section, the said section being taken on the line W X Y Z Figure 2;
and
Figure 4 represents in plan a portion of the delivery or exit valve.
Figures 3 and 4 are drawn to the same scale as Figure 2.
The same letters of reference indicate the same parts in the several figures of
the drawings.
A is the air compressor cylinder; B is the air compressor piston of the same and
C is the piston rod of the said air compressor piston B (see Figure 1) D is the air
inlet pipe and the delivery pipe; F is the inlet valve and G, G are the delivery
valves at the front end of the air compressor cylinder A and F2, G' G² are the
like parts at the rear end of the said air compressor cylinder.
We will describe the improvements in the said inlet valves F F' and delivery
valves G, G, G2, G3 constituting the said invention in connection with the
valves F, G, G' at the rear end of the air compressor cylinder it being understood
that the corresponding valves F, G, G at the front end are of the same construction
and have the same action as those at the rear end and corresponding parts of the
said valves at the front end of the air compressor cylinder are marked with the
same letters of reference as those at the rear end excepting that the reference
numeral 2 is omitted from the letters at the said front end.
a² is the inlet valve proper connected by the link 6' to the piston c² working in
the small supplementary cylinder d² on the cover of the air compressor cylinder A.
The said supplementary cylinder is in communication by means of a pipe e³
(see Figure 1) with the opposite end of the air compressor cylinder A. The piston
rod of the piston c has on its outer end a cap g² which is forced outwards
by means of the spring h³.
The action of the said inlet valve is as follows ;-During the first portion of the
stroke of the air compressor piston B the inlet valve a' is opened by suction as
usual and takes the position indicated in dotted lines in Figure 3 but as the air in
front of the said air compressor piston is compressed a portion of it passes by means
of the pipe to the small supplementary cylinder the piston of which is now
maintained in its forward position by the pressure of the air supplied from the air
compressor cylinder. The said inlet valve a² is thereby maintained in its fully
open position until the air compressor piston B in the air compressor cylinder A
has completed or nearly completed its stroke and a full charge of air at atmospheric
pressure is drawn into the said cylinder A. The piston B on or just before the
completion of its stroke passes the point where the pipe e' communicates with the
compressor cylinder A and the small supplementary cylinder d' which was in
communication with the compression side of the air compressor piston B is now in
communication with the suction side of the said air compressor piston. The
pressure on the piston c is consequently withdrawn and the spring effects the
closing of the inlet valve a².
k³
m²
The delivery valve G consists of the piston provided with the packing rings
¿ ³
the said piston working in the cylinder opening into the delivery pipe E at m³,
When the air compressor piston B is retiring from the said valve G the piston i
is forced home so as to close the said valve by the spring n² acting on a collar or
disc p on the piston rod q2 of the said valve. The said piston rod q2 has on its
outer end a second or concussion piston working in an air cylinder the said
cylinder having a hole t' near its middle and a smaller hole u at its inner end for
regulating or retarding the too sudden return of the delivery valve piston on its
return or closing stroke.
The action which we have described with reference to the valves and parts at the
rear end of the air compressor takes place with respect to the valves and parts at
the front end of the air compressor; the corresponding parts at the front end are
marked with the same letters of reference excepting that the numeral 2 is omitted
from the letters of reference at that end.

page_text: 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 the Valves of Air and Gas
Compressors" ;-
First. In air and gas compressors, connecting the inlet valve by means of a link
to a piston working in a small supplementary cylinder the said cylinder being in
communication during nearly the whole of the air or gas compressor piston's stroke
with the compression side of the said air or gas compressor piston, the inlet valve
being closed on the air or gas compressor piston passing the point where the pipe
from the small supplementary cylinder communicates with the air or gas compressor
cylinder by a spring acting on the piston of the said small supplementary cylinder
substantially as herein before described and illustrated in the accompanying
drawings.
Secondly. In air and gas compressors, making the delivery valve in the form of
a piston working in a cylinder and the combination therewith of a spring acting on
the said piston for cushioning the stroke of the said piston valve on the air or gas
compressor piston making its delivery stroke and for closing the said valve on the
suction stroke of the said air or gas compressor piston the said delivery valve
preferably having on its outer end an additional piston working in an air cylinder
for preventing shock or concussion on the closing of the delivery valve substantially
as hereinbefore described and illustrated in the accompanying drawings.
Dated the Twelfth day of March 1894.
TANGYES LIMITED,
W. J. PARKINS,
Secretary.
THOMAS JEFFERISS.