IMPROVEMENTS IN AIR PUMPS
Year: 1876

page_text: LETTERS PATENT to Alfred Vincent Newton, of the Office for Patents, 66,
Chancery Lane, in the County of Middlesex, Mechanical Draughtsman, for
the Invention of "IMPROVEMENTS IN AIR PUMPS." A communication from
abroad by William Frazer Garrison, of Brooklyn, in the State of New York,
United States of America.
Sealed the 15th May 1877, and dated the 21st November 1876.
PROVISIONAL SPECIFICATION left by the said Alfred Vincent Newton at
the Office of the Commissioners of Patents on the 21st November 1876.
ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Mechanical Draughtsman. "IMPROVEMENTS IN AIR PUMPS."
This Invention more particularly relates to air pumps for either compressing or
exhausting purposes, in which duplicate single-acting pistons, arranged to work in
separate cylinders and operating alternately to produce compression or exhaustion
of the air, are used, also in which said cylinders at their one end are provided with
outlet valves of the full area of the cylinders.
The Invention as applied to an air compressor or air-compressing pump consists
in a combination of an air-compressing piston arranged to pass in its delivery stroke
beyond the face of the seat of the outlet valve, an air inlet valve of approximate
area with said piston, and an outlet valve constructed to cover and lap over the
delivery end of the bore of the cylinder, said outlet valve and piston being faced to
make a close joint with each other throughout the area of the piston, whereby
not only a quick and free supply of air is procured for the working cylinder with
but a restricted stroke or action of the inlet valve, likewise a full or free discharge
of the compressed air obtained, but the entire volume of compressed air is expelled
from the cylinder and none of said air left between the outlet valve and piston to
expand or spread itself in the back or non-compressing stroke of the piston.
Furthermore the Invention as applied to an air compressor consists in an enlarged
chamber at the delivery end of each cylinder, of the compressor formed by an
extension of the cylinder and constructed to constitute a seat for the outlet valve,
also provided with an outlet for the compressed air, in combination with, a
detachable cylinder lid or cover at the outer end of said enlarged chamber, and, an
air-compressing piston constructed and arranged to work within the reduced portion
[Price 6d1

page_text: of the cylinder, and beyond the seal of the outlet valve, whereby increased facility is
afforded for giving access to and removing or replacing the outlet valve without
braking the outlet pipe connections.
The Invention in its application to an air compressor also consists in an air-com-
pressor cylinder within which a single-acting piston works, provided near its open
or receiving end with one or more free air inlets arranged so that the same are
passed or exposed by the piston in its back stroke in combination with one or more
inlet valves in the piston, whereby in case of said valves sticking or failing to
supply the cylinder with a proper amount of air, the deficiency is made up by the
free inlets and a full supply of air is at all times insured.
Again, the Invention in its application to an air compressor consists in a novel
combination of parts for connecting and operating the pistons of the compressor,
having duplicate single-acting pistons, whereby the greatest facility is afforded for
the adjustment of said pistons relatively to the delivery valves of the compressor, to
meet disturbances consequent and wear and tightening up of the driving con-
nections, and great simplicity and efficiency generally are obtained.
Likewise, the Invention in its application to an air compresser consists in a
combination with the air compressor of a pressure limiting device applied to said
compressor or its connections outside of its outlet valve or valves, and so constructed
and connected with a throttle or other controlling valve of the engine driving the
compressor that while said pressure limiting device exerts no controlling action on
the compressor so long as the latter does not compress the air beyond a given or
maximum pressure, any excess of pressure beyond such point or limit is prevented
without waste or blowing off of the compressed air, by the pressure limiting device
then acting upon the controlling valve of the engine to arrest or reduce the notion
of the engine and its attached compressor. Such pressure limiting device conse-
quently forms a close and economical check or safeguard against excessive com-
pression of the air by the compressor.
The Invention in its application to an air exhauster or air exhausting pump
consists in or comprises virtually like combinations of parts or most of them as have
been herein-before enumerated in the application of the Invention to an air com-
pressor, subject only to such changes as are necessary to make the pump exhaust
instead of compress air.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alfred Vincent Newton in the Great Seal Patent Office on the 19th May
1877.
ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Mechanical Draughtsman. "IMPROVEMENTS IN AIR PUMPS."
A communication from abroad by William Frazier Garrison, of Brooklyn, in the
State of New York, United States of America.
This Invention more particularly relates to air pumps for either compressing or
exhausting purposes, in which duplicate single-acting pistons, arranged to work in
separate cylinders and operating alternately to produce compression or exhaustion
of the air, are used, also in which said cylinders at their one end are provided with
outlet valves of the full area of the cylinders.
The Invention as applied to an air compressor or air-compressing pump consists
in a combination of an air-compressing piston arranged to pass in its delivery
stroke beyond the face of the seat of the outlet valve, an air inlet valve of
approximate area with said piston, and an outlet valve constructed to cover and lap
over the delivery end of the bore of the cylinder, said ontlet valve and piston being
faced to make a close joint with each other throughout the area of the piston,
whereby not only a quick and free supply of air is procured for the working

page_text: cylinder with but a restricted stroke or action of the inlet valve, likewise a full or
free discharge of the compressed air obtained, but the entire voluine of compressed
nir is expelled from the cylinder and none of said air left between the outlet valve
and piston to expand or spread itself in the back or non-compressing stroke of the
piston.
Furthermore the Invention as applied to an air compressor consists in an enlarged
chamber at the delivery end of each cylinder of the compressor, formed by an
extension of the cylinder and constructed to constitute a sent for the outlet valve,
also provided with an outlet for the compressed air, in combination with a
detachable cylinder lid or cover at the outer end of said enlarged chamber, and an
air-compressing piston constructed and arranged to work within the reduced portion
of the cylinder and beyond the seat of the outlet valve, whereby increased facility is
afforded for giving access to and removing or replacing the outlet valve without
breaking the outlet pipe connections.
The Invention in its application to an air compressor also consists in an air-com-
pressor cylinder, within which a single-acting piston works, provided near its open
or receiving end with one or more free air inlets arranged so that the same are
passed or exposed by the piston in its back stroke in combination with one or more
inlet valves in the piston, whereby in case of said valves sticking or failing to
supply the cylinder with a proper amount of air, the deficiency is made up by the
free inlets and a full supply of air is at all times insured.
Again, the Invention in its application to an air compressor consists in a novel
combination of parts for connecting and operating the pistons of the compressor
having duplicate single-acting pistons, whereby the greatest facility is afforded for
the adjustment of said pistons relatively to the delivery valve of the compressor, to
meet disturbances consequent and wear and tightening up of the driving con-
nections, and great simplicity and efficiency generally are obtained.
•
Likewise, the Invention in its application to an air compressor consists in a
combination with the air compressor of a pressure limiting device applied to said
compressor or its connections outside of its outlet valve or valves, and so constructed
and connected with a throttle or other controlling valve of the engine driving the
compressor that while said pressure limiting device exerts no controlling action on
the compressor so long as the latter does not compress the air beyond a given or
maximum pressure, any excess of pressure beyond such point or limit is prevented
without waste or blowing off of the compressed air, by the pressure limiting device
then acting upon the controlling valve of the engine to arrest or reduce the motion
of the engine and its attached compressor. Such pressure limiting device conse-
quently forms a close and economical check or safeguard against excessive com-
pression of the air by the compressor.
The Invention in its application to an air exhauster or air exhausting pumps
consists in or comprises virtually like combinations of parts, or most of them, as
have been herein-before enumerated in the application of the Invention to an air
compressor, subject only to such changes as are necessary to make the pump exhaust
instead of compress air.
Having thus specified the objects and nature of the Invention, its description will
be proceeded with in connection with the accompanying Drawing.
Fig. 1 represents a plan of an air compressor or air compressing pump constructed
in accordance with the Invention, and having the engine which operates the com-
pressor attached; Fig. 2 is a vertical longitudinal section on the line x, x, of said
pump or compressor; Fig. 3 is a similar section upon a larger scale through one of
the cylinders only; Fig. 4 is a longitudinal section upon a still larger scale of one of
the air inlet valves pertaining to either air compressing piston.
Fig. 5 is a side view, and Fig. 6 a plan of the air compressor or pump in part,
showing a modification of the means by which motion is communicated from the
engine to the pump.
Fig. 7 is a sectional plan of an air exhauster or an exhausting pump in part, with

page_text: certain portions of the Invention applied thereto; and Fig. 8 is a transverse section
through one of the pump cylinders on the line y, y.
Referring in the first instance to Figures 1, 2, 3, and 4 of the Drawing, A, A, are
two air-compressing cylinders containing single acting pistons B, B, and set in the
same plane with their air-receiving ends which are left open facing each other.
The two pistons B, B, are connected to work simultaneously in the same direction,
and so that they alternately compress the air in their respective cylinders. Both
cylinders A, A, which may be arranged within water tanks C, C, to maintain a
desirable cooling effect are secured on the same bed D which carries the engine E
that operates the compressor from or by its main shaft F or crank bon said shaft,
which crank it is preferred to make of less throw than the engine shaft c. Each
cylinder A is formed with an enlarged chamber H at its outer and compressing or
delivery end between the reduced portion of the cylinder in which the piston works
and the lid or cover which closes said end of the cylinder. This enlarged chamber H
however is divided from said lid or cover, and is constructed to form a seat for an
outlet or delivery valve G of larger area than the working bore of the cylinder so
as to cover or overlap said bore. The enlarged chamber H which is an end
extension of the cylinder has also attached to it the outlet d by which the com-
pressed air escapes into a receiver or elsewhere, the alternate compressing action of
the two pistons keeping up a constant supply of compressed air. Each valve g is
closed by a spring c and is faced to form a flush or close joint with the opposite
face of its respective piston B, and the back of the air inlet valve I is constructed
to be flush when closed with the said face of the piston. This construction combined
with an extended stroke of either piston B beyond the outer end of the bore of its
cylinder A, as shown in Figs. 2 and 3, insures a close meeting of such piston B at
the end of its compressing stroke with the valve G throughout the whole area of
said piston, and makes positive or certain the expulsion of all the compressed air
from the cylinder in which said piston works, and so that no compressed air remains
between the outer valve G and piston B to expand within the cylinder during the
back stroke of the piston. This not merely provides for a free discharge of the
compressed air and for a perfect and thorough expulsion thereof during each com-
pressing stroke of the piston, but by reason of the chamber H being a portion of
the cylinder itself and forming the seat for the valve G also having the outlet d
attached to it, the end cover of the cylinder may readily be removed without
detaching the outlet connections whenever it is necessary to get at or remove the
outlet valve, G.
Furthermore the air inlet valve I within either piston B is of an approximate
area with said piston, and is preferably constructed of a cylindrical or cup form with
a bevilling head made of hard rubber or equivalent material, backed or supported
back and front with metal, as shewn in Figures 3 and 4. Said valve is provided
with an annular series of air inlets n, n, around its body in proximity with its head,
and requires but a very restricted stroke or action to give a quick and free supply
of air to the cylinder in which its piston works, and is almost noiseless in its action
when closing besides being very durable. These results are largely due to the
approximate area of the valve relatively with the piston.
To guard against any deficiency in the supply of air to either cylinder A between
the outer or delivery valve G and the piston B which works in connection there-
with, during the back stroke of said piston and by its inlet valve I which opens to
supply air entering by the inner open end of the cylinder A, either cylinder A is
constructed near its open or inner end with one or more free air inlets or passages f
arranged so that the piston, as shown to the right-hand of Fig. 2, in completing its
back stroke, passes or exposes said free air inlet or inlets f, and thus makes up any
deficiency of air supply-through the valve I.
The piston B, B, are connected and to work simultaneously in the same direction
as followsJ is a slotted trunk or connection between the pistons B, B, providing
ready access to the air inlet valves J, and having a box g which forms a bearing for
a rocking cross head K. This cross head is connected with the operating crank b of

page_text: the nuts.
the compressor by a strap shaped or forked connecting rod L, the open ends of
which are secured to the cross heads by nuts h, h, arranged to screw on to said open
ends on opposite sides of both ends of the cross head which is thus clamped between
This not only forms a simple and efficient driving means for the pistons
B. B, but by means of the nuts h, k, provision is made for adjusting said pistons
relatively to the outlet valves G, G, of their respective cylinders on keying or
tightening up the connecting rod L on the wrist pin of the crank b as wear requires
or as other circumstances may make necessary.
Furthermore, by the cross head K being fitted to vibrate at and along with the
inner end of the forked connecting rod L within the box g of the slotted connection J,
an elongated bearing is provided for said cross head. This materially reduces wear
and does away with the necessity of bushing the connection between said connecting
rod and the piston.
Figures 5 and 6 show a different combination of means for operating the pistons
B, B thus a crank b₁ driven by the engine has a box c¹ fitted on its wrist pin,
which box is free to slide up and down between adjustable guides d', d, carried by
a plate secured to the slotted trunk J which connects the two pistons.
M, in Figures 1 and 2, is a pressure limiting device applied for convenience sake
to a compressed air delivery pipe or connection coupling the outlets d, d, but
which may be applied to the compressor or its connections at other parts or places
outside of the outlet valve or valves, as for instance, to the compressed air receiver
when such a receptacle is used. This pressure limiting device consists of a cylinder
or chamber closed by a flexible diaphragm, or by a piston exposed to the pressure of
the air as it is delivered by the compressor, and loaded to resist any given maximum
pressure which the compressor should work up to. Thus 7 is an hiermetically sealed
flexible diaphragm exposed on its under side to the pressure of the compressed air
supplied by the compressor, and s a weighted lever bearing down on said diaphragm,
and connected by a rod t with the throttle valve u of the engine. So soon as the
pressure of the air supplied by the compressor exceeds the resistance on the
diaphragm produced by the loaded lever the latter is raised and the throttle valve
of the engine partly or wholly closed, thus retarding or arresting the motion of the
compressor; this occurs whenever the pressure which the compressor should work
up to has been reached, or rather so soon as there is any tendency to exceed such
pressure, and by the closed construction and action of said pressure limiting device
it accomplishes the desired effect without wasting or blowing off the compressed air,
and it does not act until the desired pressure has been reached.
A pressure
limiting device operating upon the principle here described may be variously
constructed, and is not restricted to the precise construction here shown for the
same, nor yet to the means represented and described for connecting it with the
engine. Said device also is equally applicable to both single and double acting air
compressors having either single or duplicate pistons.
Referring in the next instance to Figures 7 and 8 of the Drawing, which show
the Invention so far as many or most of its novel combinations of parts are
concerned applied to an air exhauster or air exhausting pump, A, A, are the two
pump cylinders containing single acting pistons B, B, and set in the same plane with
their air receiving or exhausting ends arranged to face each other, as in the case of
the air compressor herein-before described, but having said ends closed instead of
being left open. Each of the pistons B, B, is arranged to pass in its outer or
delivery stroke beyond the face of the seat of the outlet valve G, but instead of
having a single inlet valve I it may be provided with a series of such valves,
presenting a large aggregate area.. The outlet valve G is also made to cover and
lap over the delivery end of the bore of the cylinder, and so that it forms a close
joint with the piston when the latter passes beyond such end of its cylinder.
Furthermore, each cylinder A, as in the case of the air compressor, is constructed
with an enlarged chamber H at its delivery end, and so that it forms a seat for the
outlet valve G of the pump, such chamber H also being provided with an outlet d
for the expelled air and having at its outer end a detachable cylinder lid or cover,
-

page_text: and each piston B working within the reduced portion of its cylinder. Instead of
however, as in the air compressor, the outlets & being connected, they may be left
disconnected from each other, and suitable air inlets or openings f¹ at or near the
inner ends of the cylinders are connected with or by a general exhaust pipe which
connects with the vessel or chamber to be exhausted.
The connection J between the piston instead of being of a slotted or hollow trunk
construction may be solid, and formed of piston rods united by the box or elongated
bearing which carries the rocking cross head K that has attached to its ends in
an adjustable manner by means of the nuts h, h, the forked driving connecting
rod L.
Having now set forth the nature of the Invention of "Improvements in Air
Pumps" as communicated to me by my foreign correspondent, and explained the
manner of carrying the same into effect, I wish it to be understood that under
the above in part recited Letters Patent I claim,-
First. The combination of an air pump piston arranged to pass in its discharging
or delivery stroke beyond the face of the seat of the outlet valve, an air inlet valve
of approximate area with said piston, and an outlet valve constructed to cover and
lap over the delivery end of the bore of the cylinder, and to form a close joint with
the piston when the latter passes beyond the seat of the outlet valve at said end of
the bore of its cylinder, substantially as specified.
Second. The enlarged chamber H at the delivery end of either cylinder A formed
by an extension of the cylinder, and constructed to form a seat for the outlet valve G
of the pump, also provided with an outlet d for the expelled air in combination
with the detachable cylinder lid or cover at the outer end of the enlarged chamber,
and the piston B constructed and arranged to work within the reduced portion of
the cylinder and in relation with the overlapping outlet valve G, substantially as
shewn and described.
Third. The combination in an air compressor with one or more air inlet valves in
the air compressing piston of one or more free air inlets f in the cylinder A near its
air receiving end but within the range of the piston, so that said inlets are uncovered
by the piston after the latter in its back stroke has passed them, essentially as and
for the purpose herein set forth.
Fourth. The combination of the connection J between the pistons with its box or
elongated bearing g, the rocking cross head K supported by and turning within
said box, the forked connecting rod L, the adjusting nuts h, h, the pistons B, B, and
the cylinders A, A, essentially as described.
Fifth. The combination with an air compressor and its operating engine of a
pressure limiting device constructed for operation substantially as and for the
purpose herein set forth.
In witness whereof, I, the said Alfred Vincent Newton, have hereunto set my
hand and scal, the Nineteenth day of May, in the year of our Lord Oue
thousand eight hundred and seventy-seven.