Improvements relating to Air Compressors.
Year: 1897

page_text: [Communicated from abroad by THE INGERSOLL-SERGEANT DRILL COMPANY, & cor-
poration organized under the Laws of the State of West Virginia, and having
its principal business office at No. 26 Cortlandt Street, in the City of New
York, in the State of New York, United States of America, Manufacturers.]
Improvements relating to Air Compressors.'
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
45 Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention to be as follows:
This invention relates to what are commonly known as air compressors but
which may be used for the compression of various gaseous bodies. The class of
such compressors to which the improvements are particularly applicable is that
in which the discharge valves open automatically and are closed by the positive
operation of mechanism in connection with the piston of the compressor or with
the motor which drives it. One object of the improvement is to prevent the said
valves from slamming open, aud another object is to provide for the cessation of
the operation of the said valves and to leave them open and thus render the com-
pressor inoperative whenever the pressure in the receiver or other place to which
the compressed air or gas is delivered by the compressor reaches a determined
maximum and so long as this maximum is maintained.
The compressor cylinder has in its heads discharge chests which are always in
free communication through a discharge passage running lengthwise of the
cylinder, with the discharge pipe through which the compressed air is discharged
to a receiver or other place. The discharge valves through which the compressed
air is delivered into the discharge chests within the cylinder heads, are of the
puppet type and close into conical seats in the inner walls of the respective cylinder
heads. These valves may have hollow cylindrical stems, the stem of each valvo
being fitted and guided in a valve box in its respective cylinder head.
This valve box consists of small cylinder and cap, the said
cylinder being formed or provided between the inner and outer walls of the
cylinder head, and the cap being fitted to and secured within the said cylinder,
the said cylinder which is opposite to and concentric with the valve seat, opening
and there
through the outer wall of the cylinder head for the insertion of the cap,
being an opening all around the inner end of said cylinder to the discharge chest.
The cap is bored centrally to receive and form a guide for the stem of the valve.
The outer end of the hore of said cap is closed by a plug which is bored centrally
to receive and form a guide for the mod of a valve tappet which projects into the
hollow stem of the valve. The plug or, as it may be called, the valve tappet guido,
is fitted in its outer end with a stuffing box for the rod of the tappet. The valve

page_text: tappet guide thus projecting within the hollow stem of the valve permits a long
guide for the tappet rod without much projection of the guide beyond the cylinder
head.
The inner open end of the valve box cylinder and the inner end of the cap are
respectively so formed, as to leave within the said cylinder, between it and the
valve stem, an annular space which constitutes a dash-pot into which the head of
the valve, which projects all around the stem and is made to fit the
said cylinder, may ontor, when the valvo completes its opening move-
ment and may so be prevented from slamming open.
The valve opens
wide automatically when the pressure in the cylinder in front of it
becomes greater than that behind it, and when wide open and received
within the dash-pot, the portion of its head which projects around the stem is so
sheathed or protected by the latter as to be unaffected by any such current of air
from the discharge passage through the chest into the cylinder as might otherwise
occur and have a tendency to close it when the valve is intended to remain open,
as when the operation of the compressor is required to cease in consequence of an
excess of pressure beyond the maximum desired in the receiver.
For the purpose of closing the valve by the positive operation of mechanism
in connection with the piston or motor of the compressor, the tappet of each valve
is connected outside of its stuffing boxx with a slide which works on a fixed guide
secured to the cylinder head. The slides of the valve tappets at each end of the
cylnder serve to make the connections with the positively operating valve-closing
nechanism. This mechanism will now be described, it includes an engaging
device which is capable of being tripped to disengage the valves and leave them
open when and while the pressure of the air delivered by the compressor reaches
and remains at the maximum desired.
An horizontal rock-shaft fitted to a long bearing which is bolted through its
flauge to one side of the bed frame of the compressor about midway of the length
of the cylinder, the said shaft and bearing being arranged transversely to the
cylinder. To the inner end of this rock-shaft is koyed or firmly secured a two-
arued swing plate. The valve tappet slides are connected permanently by a rod
with the two arms respectively of this swing plate. A rocker arm is fitted to
rock on a stationary journal formed on the exterior of the rock shaft bearing.
This rocker arm is permanently connected by a rod with the cross-head of the air
compressor piston so that its rocking motion continues while the compressor is in:
motion. To the outer end of the rock-shaft there is keyed or firmly secured a
sector-plate into which is dovetailed or firmly secured a tooth preferably of
hardened steel, and to the rocker arm there are pivoted two pawls constituting
a trippable engaging device for engaging with the tooth of the sector plate ou
opposite sides thereof and so connecting the rocker arm with the rock-shaft that
the movement receiver by the said rocker arm from the compressor cross-head will
be imparted to the rock-shaft and its swing plate and the movement of the cross-
head will thus be made to produce the closing movement of the discharge valves at
the termination of every stroke of the compressor piston so long as the engagement
of the pawls and the tooth continues. The engagement of the pawls is maintained
by a spring attached to the rocker arm by a stud, the said spring holding the
pawls against the arc-formed edge of the sector plate from which the tooth projects
and insuring their engagement with the tooth until they are required to be tripped
therefrom.
4
The tripping device for tripping the pawls out of engagement with the tooth &
consists in part of a pawl lifter and in part of a small upright air cylinder and
plunger. The said lifter is a sliding bolt which is fitted to a guiding groove in
the rocker arm E' between the said arm and the sector plate, the said bolt being
made with a yoke at its lower end which surrounds the rock-shaft and having at
its upper end a bit which projects outwards a little way under the pawls. The 5
cylinder is fixedly secured below the rock-shaft to the flange of the rock-shaft
bearing by studs and screw-bolts. The plunger which is fitted air-tight to the

page_text: said cylinder has projecting from it through the upper end of the cylinder a square
rod which is directly opposite the pawl lifter. The lower end of the cylinder has
connected with it a pipe for supply air to it from the air receiver or other place
to which the air is delivered by the compressor whenever the pressure of the 80
delivered air reaches the determined maximum, the said air being admitted to the
said pipe under the control of any valve suitably loaded to shut off the said air
from said pipe and from the cylinder so long as the pressure of the said air is less
than the said maximum but to admit the said air through the said pipe to the
cylinder when the maximum is reached and so long as it is maintained. The
piston has applied to it within the cylinder a spring which presses downwards
upon it and which when there is no air admitted to the cylinder, depresses the
piston to a position in which it is inoperative upon the paw! lifter so that until
the maximum pressure of the delivered air is reached, the tripping device is
inoperative upon the pawls and the operation of the valves continues; but when
the air is admitted to the cylinder its pressure overcomes the force of the spring
and presses upward the piston which presses up the lifter and so disengages the
pawls and allows the movement of the rocker arm derived from the compressor
cross-head to continue without producing the movement of the rock-shaft by which
the closing of the valves is effected and so the valves remain open.
In order to bring and keep the sector plate and swing plate to their central
position in which they hold back each valve tappet far enough to leave its valvo
wide open, after the tripping of the pawls, there are provided on the face of the
rocker arm, on opposite sides of the medinu radial line of said arm, two projections
which act respectively on two other projections on the back of the sector plate,
two of the projections being at a corresponding distance from the axis of the shaft
and the remaining two projections being at a corresponding, but greater, distance
from said axes, that they may not interfere with one another.
The said pro-
jeotions are so spaced that when the sector plate is in its central position, while the
rocker arm continues in motion, the projections on the latter will oscillate freely
between those ou the sector plate without any action on the latter, but whenever
the sector plate is left to one side or other of its central position, the projection as
the case may be, comes into operation on the other projection and so brings the
said plate back to the central position where it then remains until the pawls again
come into operation.
When the pressure of the delivered air falls to or within the determined
maximum and the air is shut off from the pipe, the piston is depressed by the
spring and the lifter is allowed to slide back in the rocker arm within rango of the
are of the sector plate and the pawls are allowed to come again into engagement
with the tooth, and connect the valves with the rocker and the valves resume their
operation.
We have herein referred to the mechanism for operating the valve tappets and
closing the valves as in connection with or connected with the compressor piston
and have represented said mechanism as connected with the cross-head of the
compressor pistou but it is evident that the connection for driving said mechanism
may be connected with any part of the compressor the movements of which aro
coincident with the movements of the piston.
50.1
1
1038

page_text: "Improvements relating to Air Compressors.'
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
45 Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention and in what manner the same is to be performed, to bo
particularly described and ascertained in and by the following statement:--
This invention relates to what are commonly known as air compressors but
which may be used for the compression of various gaseous bodies. The class of
such compressors to which the improvements are particularly applicable is that
in which the discharge valves open automatically and are closed by the positive
operation of mechanism in connection with the piston of the compressor or with
the motor which drives it.
One object of the improvement is to prevent the said valves from slamming
open, and another object is to provido for the cessation of the operation of the
said valves and to leave them open and thus render the compressor inoperativo
whenever the pressure in the receiver or other place to which the compressed air
or gas is delivored by the compressor reaches a determined maximum and so long
as this muximum is maintained.
The nature of the invention will be described with reference to the accom-
panying drawings of a compressor embodying my invention which may be used
for gas or air but the operation of which will be particularly described with
reference to the use of air.
Figure 1 represents a side elevation of a compressor constructed according to
my invention.
Figure 2 is an end elevation thereof.
Figures 3 and 4 represent central vertical sections of one of the cylinder heads
and of the discharge valve and its box in the head, drawn to a larger scale
Figure 3, showing the valve closed and Figure 4 showing it open.
Figure 5 is a side view, drawn to a larger scale than Figures 1 and 2 but smaller
than Figures 3 and 4, of the principal parts of the valve-operating mechanism.
Figure 6 represents a transverse section in the line 5, 5, of Figure 5.
Figure 7 is n sido view of what is hereinafter termed the swing plate of the
valve operating mechanism and
Figures 8 and 9 represent respectively a face view and a side view of what is
hereinafter termed the pawl lifter.
A designates the compressor cylinder having in its heads A', as shown in
Figures 3 and 4, discharge chests A which are always in free communication
through a discharge passage A³ running lengthwise of the cylinder, with the dis-
charge pipe A through which the compressed air is discharged to a receiver or
other place. The discharge valves B, only one of which is shown, through which
the compressed air is delivered into the discharge chests within the cylinder
heads, are of the puppet type and close into conical scats a in the inner walls of
the respective cylinder heads. These valves are represented as having hollow
cylindrical stems b, the stem of each valve being fitted and guided in a valve
box C D in its respective cylinder head. This valve box consists of a small
cylinder C and a cap 1), the said cylinder C being formed or provided between the
inner and outer walls of the cylinder head A and the cap D being fitted to aud
secured within the said cylinder C, the said cylinder which is opposite to and
concentric with the valve seat, opening through the outer wall of the cylinder head
for the insertion of a cap D, and there being an opening c all around the
inner end of said cylinder C to the discharge chest A* The Dis bored
cap
centrally to receive and form a guide for the stem of the valve.
The outer end

page_text: The valve
of the bore of said cap is closed by a plug d which is bored centrally to receive
and form a guide for the rod of a valve tappet e which projects into the hollow
stem of the valve. The plug d or, as it may be called, the valve tappet guide, is
fitted in its outer end with a stuffing box f for the rod of the tappet e.
tappet guide thus projecting within the hollow stem of the valve permits a long
guide for the tappet rod without much projection of the guide beyond the cylinder
head.
The inner open end of the valve box cylinder C and the inner end of the cap D
are respectively so formed, as may be best understood by reference to Figures 3
and 4, as to leave within the said cylinder, between it and the valve stem, an
annular space g which constitutes a dash-pot into which the head of the valve,
which projects all around the stem and is made to fit the said cylinder C, may
outer, as shown in Figure 4, when the valve completes its opening movement and
may be so prevented from slamming open. The valve opens wide automatically
when the pressure in the cylinder in front of it becomes greater than that behind it,
and when wide open and received within the dash-pot g as shown in Figure 4,
the portion of its head which projects around the stein is so sheathed or protected
by the latter as to be unaffected by any such current of air from the discharge
passage A through the chest A* into the cylinder as might otherwise occur and
have a tendency to close it when the valve is intended to remain open, as when the
operation of the compressor is required to cease in consequence of an excess of
pressure beyond the maximum desired in the receiver.
For the purpose of closing the valve by the positive operation of mechanism
in connection with the piston or motor of the compressor, the tappet e of each
valve is connected outside of its stuffing box f, as shown in Figures 1, 2, 3, 4,
with a slide which works on a fixed guide secured to the cylinder head. Tho
slides of the valve tappets e at each end of the cylinder serve to make the con-
nections with the positively operating valve-closing mechanism. This mechanism
which is illustrated in Figures 1, 2, 5, 6, and will now be described, includes an
engaging device which is capable of being tripped to disengage the valve and leave
them open when and while the pressure of the air delivered by the compressor
renches and remains at the maximum desired.
E (Figures 1, 2, 3, 6) is a horizontal rock-shaft fitted to a long bearing F which
is bolted through its flange F to one side of the bed frame G of the compressor
about midway of the length of the cylinder A, the said shaft and bearing being
arranged transversely of the cylinder. To the inner end of this rock-shaft Ei
keyed or firmly secured a two-armed swing plate 1* of which a front view is
given in Figure 7. The valve tappet slides are connected permanently by a
rod with the two arms respectively of this swing plate. E is a rocker arm fitted
to rock on a stationary journal m (Figure 6) formed on the exterior of the rock
shaft bearing . This rocker arm permanently connected by a rod h with
the crosshead of the air compressor piston so that its rocking motion continues
while the compressor is in operation. To the outer end of the rock-shaft E there
is keyed or firmly secured a sector plate Es into which is dovetailed or firmly sccured
a tooth preferably of hardened steel, and to the rocker arm E there are pivoted
two pawls (Figures 1 and 5) constituting a trippable engaging device for
engaging with the tooth of the sector plate on opposite sides thereof and so
connecting the rocker arm E' with the rock-shaft that the movement received
by the said mocker arm from the compressor cross-head will be imparted to the
rock-shaft and its swing plate E and the movement of the cross-head will thus
be made to produce the closing movement of the discharge valves at the termina-
tion of every stroke of the compressor piston so long as the engagement of the
pawls and the tooth a continues. The engagement of the pawls is maintained by
a spring & attached to the rocker arm E¹ by a stud q', the said spring holding the
pawls against the are-formed edge of the sector plate from which the tooth n
projects and insuring their engagement with the tooth until they are required to
be tripped therefromi.

page_text: The tripping device for tripping the pawls out of engagement with the
tooth n consists in part of a pawl lifter of which Figure 8 is n front view and
Fig. 9 a side view and in part of a small upright air cylinders and plunger t
shewn in Figures 5 and 6. The said lifter is a sliding bolt which is fitted to a
guiding groove in the rocker arm E' between the said arm and the sector plate
the said bolt being made with a yoke at its lower end which surrounds the rock-
shaft and having at its upper end a bit which projects outwards a little way
under the pawls p as shown in Figure 5. The cylinders is fixedly secured below
the rock-shaft E to the flange of the rock-shaft bearing F by studs u and screw
bolts . The plunger which is fitted air-tight to the said cylinder has projecting
from it through the upper end of the cylinder a square rod v which is directly
opposite the pawl lifter 7. The lower end of the cylinders has connected with it
a pipe o for supplying air to it from the air receiver or other place to which the air
is delivered by the compressor whenever the pressure of the so delivered air reaches
the determined maximum, the said air being admitted to the said pipe to under
the control of any valve suitably loaded to shut off the said air from said pipe and
from the cylinders so long as the pressure of the said air is less than the said
maximum but to admit the said air through the said pipe to the cylinder when the
maximum is reached and so long as it is maintained. The piston has applied to
it within the cylinder a spring r which presses downwards upon it and which when
there is no air admitted to the cylinder, depresses the piston to a position in which
it is inoperatve upon the pawl lifter so that until the maximum pressuro of the
delivered air is reached, the tripping device is inoperative upon the pawls ? and
the operation of the valve continues; but when the air is admitted to the cylinders
its pressure overcomes the force of the spring and presses upward the piston
which presses up the lifter and so disengages the pawls p and allows the move-
ment of the rocker arm derived from the compressor cross-head to continue without
producing the movement of the rock-shaft by which the closing of the valves is
effected and so the valves remain open.
In order to bring and keep the sector plute F and swing plate E* to their
central position in which they hold back each valve tappet far enough to leave
its valve wide open, as illustrated by the valve and tappet in Figure 4 after the
tripping of the pawls p, there are provided on the face of the rocker arm, as shewn
in Fig. 5, on opposite sides of the median radial line of said arm, two projec-
tions 8*9*, which act respectively on two projections 8, 9 shewn in dotted outline
on the same Figure on the back of the sector plate the two projections 8 and 8*
being at a corresponding distance from the axis of the shaft E and the two pro-
jections 9 9 being at a corresponding but less distance from said axis, that 8
may not interfere with 9* nor 8 with 9. The said projections are so spaced that
when the sector plate is in its central position, while the rocker arm continues in
motion, the projections 8*9* on the latter will oscillate freely between those 8, 9 on
the sector plate without any action on the latter, but whenever the sector plate is
left to one side or other of its central position, the projection 8 or 9*, as the case may
be, comes into operation on the projection 8 or 9 and so brings the said plate back
to the central position where it then remains until the pawls 2 again come into
operation. The projections 8 and 9 are also shown in Figure 6.
2
When the pressure of the delivered air falls to or within the determined
maximum and the air is shut off from the pipe to, the piston is depressed by the
spring and the lifter is allowed to slide back in the rocker arm within range of
the arc of the sector plate and the pawls p are allowed to come again into engage-
ment with the tooth n, and connect the valves with the rooker and the valves
resume their operation.
We have herein referred to the mechanism for operating the valve tappets and
closing the valves as in connection with or connected with the compressor piston
and have represented said mechanism as connected with the cross-head of the com-
pressor piston but it is evident that the connection for driving said mechanism

page_text: may be connected with any part of the compressor the movements of which are
coincident with the movements of the piston.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, as communicated to me
by my foreign correspondents, I declare that what I claim is :-
--
1. The combination in an air or gas compressor, of a discharge valve having a
stem of smaller diameter than its head, an annular dash-pot in which the portion
of the head projecting around the stem of the valve is sheathed when the valve is
open, substantially as and for the purpose herein described.
2. The combination with an air or gas compressor cylinder having a hollow
head constituting an air discharge chest, of a dash-pot within the said head opening
into the said discharge chest and a discharge valve which when open has its hend
sheathed within said dash-pot, substantially as herein described.
3. The combination in an air or gas compressor, of a valve box, a valve having
a hollow stem, a guide in said box for said stem, a valve-operating tappet entering
the said stem, and a guido for said tappet provided in the valve box and pro-
jecting into the hollow valve stem, substantially as heroin described.
4. In an air or gas compressor, the combination with a discharge valve having
a hollow stem and a head projecting around said stem, of a valve box composed in
part of a cylinder and in part of a cap which is fitted to suid cylinder and which
contains a guide for said stem the said box and stem having formed between them
an annular dash-pot for the projecting head of the valve, a valve tappet entering
said hollow stem, a guido for said tappet provided in said cap and projecting
within said hollow stem, and a stuffing box for said tappet provided in said
guide, substantially as herein described.
6. In an air or gas compressor, the combination with a discharge valve which
opens by the pressure of the air or gas in the compressor cylinder and positively
operating mechanism for closing said valve including a trippable engaging device,
of a tripping device under the control of the air delivered by the compressor for
tripping said engaging device to prevent the operation of said closing mechanism
and leave the said valve open whenever the pressure of the said delivered air or gas
reaches a determined maximum and so long as said pressure remains at or above
said maximum, substantially as set forth.
6. In an air or gas compressor, the combination with the discharge valves, of
tappets for closing said valves, a rock-shaft having arms connected with said
tappets, a driving rocker arm loose around said rock-shaft and connected with the
compressor piston, a trippable engaging device for engaging said rocker arm with
the rock-shaft and a tripping device under the control of the air or gas delivered
by the compressor for tripping said engaging device when the pressure of the
delivered air or gas reaches a determined maximum, substantially as herein
described.
7. In a discharge-valve closing mechanism for an air or gas compressor, the
combination of a rock-shaft having affixed thereon arms connected with the dis-
charge valves and having also affixed thereon a plate from the edge of which
projects a tooth, a rocker arm loose around said rock-shaft and connected with the
piston of the compressor pawls on said rocker arm for engaging with said tooth,
and a lifter under the control of the air or gas delivered by the compressor fitted
to slide within said plate for disengaging said pawls from said tooth, substantially
as horoin described.
8. The combination of the valve closing rock-shaft E having affixed thereon the
two-armed swing plate connected with the valves and the toothed sector-plate F,
the bearing for said rock-shaft having a journal m on its exterior, the driving
ocker arm E fitted loosely to said journals and connected with the piston of the
compressor, the spring-actuated pawls p on said rocker-arm for engaging with tho
aid toothed sector plate, the lifter on the said rocker arm for disengaging said

page_text: pawls, the cylinders containing the piston for operating said lifter, all substan-
tially as herein described.
9. The combination with the valve operating rock-shaft of the toothed sector plate
affixed to said shaft, the driving rooker arm loose around said rock-shaft and
carying pawls for engaging with said toothed plate, and the lifter ou said rocker
arm for disengaging suid pawls from said plate, the said sector-plate and rocker
arm being furnished respectively with projections 8, 8, 9, 9* for bring the rock-
shaft to a central position when the said pawls are disengaged, substantially as
herein described.
HASELTINE LAKE & Co.
45, Southampton Buildings, London. W,C. Agents for the Applicant.