Improvements in Compound Compressors for Air and other Gaseous or Aeriform Bodies.
Year: 1891

page_text: Date of Application, 21st July, 1891-Accepted, 22nd Aug., 1891
COMPLETE SPECIFICATION.
Improvements in Compound Compressors for Air and other Gaseous
or Aeriform Bodies.
I, HENRY CLARK SERGEANT of Westfield in the County of Union and State
of New Jersey, 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 :-
The object of this invention is to simplify the construction and increase the
efficiency of compound compressors, and to afford facility for examination and repair
of the interior parts thereof.
I will first describe the invention in detail with reference to the drawings, and
afterwards point out its novelty in claims.
Fig. 1 represents a central longitudinal section of a. compressor embodying my
invention.
Fig. 2 is a transverse sectional view, of which one half is taken in the line of
Fig. 1, and the other half in the line yy thereof.
Fig. 3 represents a central longitudinal section of a compressor, illustrating a
modification of that shewn in Fig. 1.
Referring first to Figs. 1 and 2, A and B are the two impression cyl nders of
unequal size, arranged end to end, in free communication with each other int their
inner or adjacent ends, and closed respectively at their outer ends by heads A¹ B',
both of which may be removable. These cylinders are represented as surrounded
by water jackets A*, B*.
CD are the pistons fitted respectively to the cylinders A and B. E is a tube
forming a connection between the pistons C D, and a communication through them.
The piston C has a central opening a, around which is the seat for a valve b,
which serves to open and close communication between the outer portion of the
cylinder A and the tube E. A cylindrical guide is provided for this valve within
the piston C, and a guard d to limit the opening in the said valve is provided within
the end of the tube E.
0
The piston D is hollow, and its internal cavity e is in free communication with the
tube E. The said piston is fitted with a valve f, which opens into the outer portion
of the cylinder B, to permit the outlet of air from the piston, and from the tube E,
into the said portion of the cylinder. This valve may be of any suitable kind, but
is represented as of the annular kind, which constitutes part of the subject matter of
Letters Patent No. 3017, dated February 25th 1890.
The piston C, in this example of the invention, is furnished with a valve i, which
may be of any suitable kind, but is represented as of the same kind as that herein-
before described in the piston D, the said valve i opening towards the outer portion
of the cylinder A, and in this case the inlet for the air to be compressed is at j, and
communicates directly with the space k formed within the two cylinders between the
pistons C D.
The cylinder head B', which is hollow to form an air chamber g, is fitted with as
many valves h as may be necessary for the exit of the compressed air from the
cylinder B, the said air passing through said chamber to the outlet l.
The two pistons connected by the tube E have the piston rod F by which they
are operated, directly connected with the piston D, and this rod passes through a
stuffing box m in the head B¹ of the smaller cylinder. This arrangement of the
piston rod F affords facility for the easy removal of both pistons, as by
disconnecting the rod F from the motor, and removing the head A' of the larger

page_text: cylinder, the two pistons and their rod are permitted to be drawn out together
through the larger cylinder.
The operation of this compressor is as follows:-
While the pistons are moving to the right, that is to say, the larger piston
moving toward the outer end of its cylinder, and the smaller one moving from the
outer end of its cylinder, the valves and h are closed, and the valves b and are
open, and fresh air is then entering by the inlet j, to the space k between the pistons,
and the air between the larger piston C and the outer end of its cylinder A is being
compressed therein, and forced out therefrom through the opening of the valve b,
through the tube E, the cavity e of the piston D, and the valve f, into the smaller
cylinder B. During the stroke in the opposite direction, the valves ƒ and 6 are
closed, and those i and are open, and the air in the cylinder B is further
compressed to the high pressure, and forced out therefrom through the opening 1,
and at the same time the space between the larger piston C and the outer end of
its cylinder is receiving, through the opening of the valve i, fresh air from the
space between the two pistons, which space is always open to the atmosphere or
source of supply of the air, or other body to be compressed.
In the example of my invention represented in Fig. 3, there is precisely the same
provision for communication through the pistons between the cylinders A and B, by
means of the tube E, as in the first described example. The only difference between
this example and the first described example, is that in this, the fresh air to be
compressed, instead of being admitted to the space between the pistons, and
passing through the piston C, is admitted to the cylinder through the valves p in
the head A thereof, and the valve i or any valve in the larger piston for forming
communication between the portion of the cylinder on opposite sides of it, is
dispensed with.
Having now particularly described, and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1. The combination in a compressor, of two single acting cylinders of unequal
calibre, arranged in line with each other, and open to each other at their inner ends,
and pistons in said cylinders, of a tube connecting said pistons, and having
communication through them for the passage of air from the outer portion of the
larger cylinder to the outer portion of the smaller cylinder, substantially as herein
set forth.
2. The combination, in a compound compressor, of two single acting cylinders of
unequal calibre arranged in line with each other, and pistons in said cylinders, of a
tube connecting said pistons, constituting a communication through said pistons
between the two cylinders, and having its inlet in the larger piston and its outlet in
the smaller one, and valves for said inlet and outlet, substantially as herein
described.
3. The combination of the two single-acting cylinders of unequal calibre, arranged
in line with each other, two pistons which work in said cylinders, and the smaller of
which is hollow, a tube connecting said pistons and forming a communication
through the larger piston into the cavity of the hollow smaller one, a valve in the
larger piston at the entrance to the tube, and a valve in the cavity of the hollow
smaller piston, substantially as herein set forth.
4. The combination of the two single-acting cylinders of unequal calibre arranged
in line with each other, open to each other at their inner ends, and closed at their
outer ends, and pistons in said cylinders, of a tube connecting and forming com-
munication through said pistons, a valve between said tube and the larger piston, a
valve in the larger piston for communicating through it with the parts of its
cylinder on each side of it, and a valve in the smaller piston for communication
between the connecting tube and the smaller cylinder, all substantially as and for
the purpose herein described.

page_text: 5. The combination in a compound compressor, of two single-acting cylinders
arranged in line with each other, open to each other at their inner ends, and closed at
their outer ends, the larger one having a removable head, and connected pistons in
said cylinders, of a piston rod projecting through the head of the smaller cylinder,
for the purpose of driving the two pistons, substantially as herein described.
Dated this 21st day of Julv 1891.
NEWTON & SON,
Agents for the Applicant.