Improvements in Air and Gas Compressors.
Year: 1890

page_text: Date of Application, 25th Feb., 1890-Accepted, 29th Mar., 1890
DI DUITIVATION.
Improvements in Air and Gas Compressors.
I HENRY CLARK SERGEANT, of 318 West Forty-seventh Street, in the City and
County of New York, in the State of New York, United States of America, 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 compressors such as are commonly known as air com-
pressors, but which are also applicable for the compression of various gaseous or
aeriform bodies.
I will proceed to describe my invention with reference to the accompanying
drawings, and afterwards point out its novelty in claims.
Fig. 1 represents a central longitudinal section of the cylinder of a double-acting
air compressor, and a longitudinal outside view of the piston and piston rods thereof,
illustrating my invention.
Fig. 2 is a transverse sectional view, taken in the line a of Fig. 1.
Fig. 3 represents a transverse section of the piston in the line yy of Fig. 4.
Fig. 4 is a sectional view of the piston, taken in the line zz of Fig. 3.
Fig. 5 represents an outside view of a portion of a ring valve which constitutes an
essential feature of my invention.
Similar letters of reference designate corresponding parts in all the Figures.
A designates a cylinder, the side walls of which are hollow, to constitute a water
jacket for the circulation of cooling water, and the heads A¹ of which are also hollow, each
containing a partition a (see Fig. 2), dividing the head in two compartments b and c,
of which constitutes the valve chamber for discharge valves d, and c constitutes a
water space for the circulation of water for cooling the cylinder. The valve chambers b
in the two cylinder heads both communicate with a longitudinal passage b¹ on the
outside of the cylinder, and the said passage bl is to have the discharge pipe connected
with it at 6³. The discharge valves d are fitted to seats in the cylinder heads, and
open outwards from the cylinder to the chambers b. The discharge valves d may be
any suitable kind, and are represented as of a well known kind, but as neither they
nor the valve chambers bb in the cylinder heads, constitute any part of the present
invention, no further description of them is necessary.
of
B designates the piston, which is hollow, and strengthened internally by radial
ribs e, and has connected with it a central tube C, which communicates with its
interior cavity f. This tube may constitute a piston rod, but in any case it constitutes
an inlet pipe for the air or other gaseous body to be compressed. The said tube works
through a stuffing box g in one of the cylinder heads, and its outer end may open to
the atmosphere, or to a cold air box, or to any source of supply for the air or gaseous
body to be compressed. In the example represented, the piston is furnished, on the
opposite side to the pipe C, with a solid rod D, passing through a stuffing box hin the
other cylinder head, for the purpose of making connection between the piston and
the motor for driving it.
The internal cavity of the piston with which the tube or pipe C communicates, is
opened and closed by valves E E, to form communication between the inlet pipe C
and the cylinder on opposite sides of the piston alternately, but the said cavity is
otherwise closed. An annular passage i is provided in each end of the piston, for the
reception of one of two ring valves E. These valves are constructed substantially
T-shaped in their transverse section, as shown in Fig. 4. This form gives them an
annular stem and a double flanged head, the flange j forming a valve-face
within the inner circumference, and the flange forming a valve face outside of the
outer circumference of said stem, the said valve faces closing against seats which are
constituted by those portions of the faces of the piston immediately within the inner
circumference, and outside of the outer circumference, of the annular passage i. The

page_text: +
inner circumference of the passage i is turned truly to form a guide for the annular
valve stem, and the inside circumference of the said stem is turned to fit easily to the
so-formed cylindrical guide. The outside circumference of the stem j is made con-
siderably smaller than the exterior circumference of the passage i, in order that
when the valve is opened, there may be a free communication between the cylinder and
the interior of the piston, but at certain intervals the said stem is thickened by bossesj³,
as shown in Figs. 3, 4, and 5, to give greater strength at such intervals where
slots are provided in the said stem, as shown in Figs. 4 and 5, the said slots
running in a direction lengthwise of the piston, and having inserted through them,
pins m, which are inserted into pin-holes provided in the piston radially thereto,
the said holes intersecting the passages i. The purpose of these pins is to prevent
the valves from getting away from the piston, and to restrict their opening movement.
The pin-holes for the reception of the pins are represented as tapered, and the pins
tapered to correspond, so that the pins may be kept in place by being driven tightly
in the said holes. The pin-holes are also represented as formed within grooves
provided in the piston for the reception of packing rings n, covering the heads or
outer ends of the said pins.
To provide for driving out the said pins after the removal of the packing rings,
when it is desirable to take out the valves, drift holes p are provided in the ends of
the piston, the said drift-holes crossing the pin-holes which receive the pins m. These
drift-holes p are plugged at their outer ends with plugs q, represented as screw plugs,
so as to prevent any communication being formed between the interior of the piston
through the said holes, but when it is intended to remove the pins m, preparatory to
taking out the valves, the said plugs q are removed, to allow a drift to be driven into
the said holes through the outer end thereof, for the purpose of driving out the said
pins m.
The operation of this compressor is as follows:-
During the stroke of the piston in either direction, one of the inlet valves E is
opened, and the other one is closed, and the outlet valves d, at one end of the cylinder,
are closed, and those at the other end opened. The air is taken into the cylinder, on
one side of the piston, through the hollow rod or inlet pipe C, the interior of the
piston, and the open valve E, and the air with which the cylinder has been filled on
the other side of the piston, at which the valve E is closed, is compressed, and forced
out through the open outlet valves d. This may be understood by reference to Fig. 1,
in which the piston is supposed to be moving to the left. The valve E at the right
hand side of the piston is open, and the air is entering the cylinder on that side of
the piston, the valves d at the right hand end of the cylinder being at the same time
closed, the air being compressed on the left hand side of the piston, where the valve E
is closed, and the air so compressed is being forced out at the left hand ond of the
cylinder through the open valves d at that end.
The compressor provided with inlet valves such as are herein described, may be
worked very rapidly. The said valves being of considerable weight, are quickly
opened and closed by their moment of inertia, on the starting of the piston in either
direction, without waiting for any pressure of air to open them. The hollow piston
rod C, or in other words the inlet pipe attached to and communicating with the interior
of the piston, presents a concentrated inlet for taking in cold air from the outside of
the building in which the air compressor is used; moreover, the dispensing with
the inlet valves in the cylinder head, enables a greater portion of the head to be
water jacketed.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:-
1. The combination, in a compressor, of a hollow piston having ports in its opposite
faces communicating with the cylinder, and a hollow piston rod or inlet pipe in free
communication with the interior of said piston at its inner end and with the atmo-
sphere or source of supply at the outer end, of valves fitted to said ports in the piston,

page_text: and opening outwardly from said cavity to the cylinder, substantially as and for the
purpose herein set forth.
2. The combination with the cylinder of a compressor, and outlet valves in the
opposite heads thereof; of a hollow piston, a hollow rod attached to said piston passing
through one of the cylinder heads, and open at the outer end to constitute an inlet
pipe, and inlet valves provided in the piston on opposite sides thereof, and opening
outwards therefrom, substantially as and for the purpose herein described.
3. The combination with the piston of a compressor constructed with an annular
passage and with two valve seats, one within the inner circumference, and the other
outside of the outer circumference of said annular passage, of a ring valve having
internal and external flanges, which form valve faces corresponding with said seats,
substantially as and for the purpose herein described.
4. The combination with the piston of a compressor constructed with an annular
passage, a cylindrical valve guide within said passage, and a valve seat on one face
of the piston at one edge of said passage, of a ring valve fitted to said guide, and
having a flange which constitutes a valve face fitted to said seat, substantially as and
for the purpose herein set forth.
5. The combination with the piston of a compressor, of a ring valve of T shaped
radial section, substantially as herein described, whereby there is formed an annular
stem, and one face within the inner circumference, and another outside of the outer
circumference of said stem, as herein set forth.
6. The combination with the piston of a compressor constructed with an annular
passage and a ring valve adapted to said passage and containing slots, of pins inserted
into the piston across the said passages, and passing through the said slots in the valve,
to retain the latter within the piston, substantially as and for the purpose herein set
forth.
7. The combination with the hollow piston of a compressor constructed with an
annular passage, with pin-holes crossing said passage, and with drift-holes crossing
said pin-holes, a ring valve adapted to said passage, and containing slots, pins inserted
into said pin holes, and through said slots, for securing the valve in place, and plugs
inserted into said drift holes, for closing the same, but removable to permit the
entrance of a drift for driving out the said pins to liberate the valve, all substantially
as herein described.
Dated this 20th day of February 1890.
NEWTON & SON,
Agents for the Applicant.