Year: 1889

page_text: I. HENRY CLARK SERGEANT, of No. 318 West 47th Street, in the City 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 :-
The object of this invention is to provide a compressor for the economical com-
pression of air to a very high tension, and especially to obtain a compressor for such
work, which is of simple construction, which will be, as nearly as practicable, free
from leakage, and which may be very easily kept in order and repaired
I will first describe the construction and operation of a compressor embodying
my improvement with reference to the drawings, and afterwards point out its novelty
in claims.
Fig. 1 is a side view, and Fig 2 a plan, of an air compressor embodying my
invention, and a steam engine for driving the same Fig 3 represents a central
vertical section of the compressor, Fig 4 a transverse vertical section in the line xx,
of Fig. 3; Fig. 5 a transverse vertical section in the line y y of Fig 3; Fig. 6 a
transverse section in the line of Fig. 3. The said transverse sections are all taken
viewed from the right.
Similar letters of reference indicate corresponding parts in the several figures.
A and B designate two compressor cylinders of unequal size, arranged end to
end. C and D designate two connected pistons fitted respectively to the two cylinders,
for the purpose of first compressing the air to a certain degree in the larger
cylinder, and afterwards further producing and completing its compression in the
smaller cylinder.
The cylinders are respectively fitted, at their outer ends, with air-tight heads A¹
and B', but they are represented in free intercommunication at their inner or adjacent
ends. The larger cylinder A is represented as provided at its inner end with an
annular head A, to which the smaller cylinder B, surrounded by a water jacket B³, is
secured, the said head A³ having a central opening to the inner end of the smaller
cylinder. The larger cylinder is also represented as surrounded by a water jacket A'.
In the inner cylinder head A', there are several openings a (see Fig. 5), through
which the inner end of the larger cylinder is always in free communication with the

page_text: atmosphere-In or on the outer head A¹ of the larger cylinder, there is a valve box E,
in which are valves e, of any suitable kind, which open outwardly from the said
cylinder into said box, and from this box a passage or conduit J, formed partly on
the cylinder jacket A2, and partly on that B, leads to a valve box F, (see Figs. 3
and 6) provided in or on the head B₁ of the smaller cylinder In this box F, are
valves, of any suitable kind, which open from the said box to the outer end of the
smaller cylinder. The cylinder head B₁ has also provided in it another valve box G,
(see Figs. 3 and 6) which contains valves g of any suitable kind opening outwards
into the said box, which is always in communication with the discharge pipe or
passage, through which the completely compressed air is delivered. In the example
represented, there is a discharge passage H formed partly on each of the water-
Jackets of the cylinders, and intended to have a discharge pipe connected with it at H¹
(see Figs. 3 and 4).
The heads of the pistons C, D, may be packed in any well-known manner,
and may
be permanently connected together in any suitable way. In the example represented,
they are connected by a hollow trunk 6, and by a piston rod c, which passes through
a stuffing box d, provided for it in the head A of the outer cylinder. This stuffing
box contains the only packing used in the compressor, except that of the piston heads
and as this box is in the larger cylinder, in which the primary compression takes
place, the liability to leakage is reduced to a minimum The hollow trunk b, and the
two piston heads, may consist of a single casting, but the said trunk is represented
in Fig. 3 as a separate tube interposed between the piston heads, to keep them at a
proper distance apart, the rod ċ serving to hold the piston heads and the tube b
together.
The piston C of the laige cylinder may be fitted with any suitable kind of valve
oi valves that will open from the inner end towards the outer end of the said cylinder
In the example represented, there is a single valve consisting of an annular dise I of
metal, which is fitted to slide upon the piston rod a distance limited by stud bolts c²,
which pass through the said disc, and are provided with heads to serve as stops to the
valve when the latter is open, as shewn in Fig 3 This valve opens and closes a
large number of openings, provided in the piston head
Passages for the circulation of water to and from the water-jackets, for cooling
the cylinders, are shown intersecting the air passages J and H, and oil passages for
oiling the cylinders and pistons are shewn intersecting the air passage J. These
water and oil passages are no part of the improvement, and are only mentioned here
to prevent contusion of the paits of the drawings.
The air compressor thus constructed is to be operated by power applied directly to
the piston rod c, to produce its reciprocating motion. In Figs. 1 and 2, this rod is
represented as connected, for this purpose, with the same cross-head h, as the piston-
rod 1, of a reciprocating steam engine. The larger cylinder A, which is turnished, as
shewn in Fig. 4, with horizontal lateral flanges m, one on each side of its water-
Jacket, is represented, in Figs 1 and 2, as supported and secured by these flanges on
the same bed-plate or frame K, with the steam engine, and the smaller cylinder is
represented as supported by being secured to the head A³ of the larger cylinder
independently of the framing or bed plate, and over-hanging the latter. This method
of supporting the smaller cylinder allows it to be easily removed to afford con-
venient access to the pistons, which can be withdrawn together when the smaller
cylinder has been removed, and the 1od has been disconnected from the crosshead
The cylinder head A³ can also be removed entirely after the removal of the pistons
and their rod.
To explain the operation of the compressor, I will first suppose the pistons to be
moving to the right of Fig 3 The piston valve I is now open Air, which is
freely supplied to the inner end of the larger cylinder through the openings a, which
are always in free communication with the atmosphere, now passes through the said
valve I, to the larger cylinder, and fills it. On the return stroke, the air, which had
thus been admitted, will be compressed by the piston C in the larger cylinder, the
valves e of which will be thereby opened by the pressure due to this compression, to

page_text: allow the said air to pass to and through the passage or conduit J, to the valves f,
which will be opened by the said pressure to admit the said air to pass through them
into the smaller cylinder; the valves g being meanwhile closed by the pressure in the
receiver, with which there is connection at H. As this stroke continues, the air is
further compressed by its being forced into the smaller space within the cylinder B,
as compared with that in A. When the pistons again move to the right, the air in
the smaller cylinder B is compressed, and forced out therefiom through the valves
by the pressure thus imparted to it, while a fresh change of air is taken into the
cylinder A between its outer end and its piston, through the openings a, and piston
valve I, as hereinbefore described.
9,
The areas of the larger and smaller cylinders and pistons may be so proportioned
to each other, and to the degree of compression desired to be obtained, that the work
of compression will be equally divided between the two pistons, and power required
to be exerted will be nearly the same in the two strokes of their reciprocating
movement
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 an air compressor, of two single-acting cylinders of unequal
calibre, arranged in line with each other, and having a valve-controlled communica-
tion between their outer ends, for the passage of an from the larger to the smaller
one, and discharge valves at the outer end of the smaller cylinder, and two pistons
connected together, and fitting said cylinders, substantially as and for the purpose
herein described
2. The combination, in an air compressor, of two single-acting cylinders of
unequal calibre, arranged in line with each other, and having heads at their outer
ends, an inlet valve to the outer end of the large cylinder, a valve-controlled
communication between the outer ends of the two cylinders, discharge valves at the
outer end of the smaller cylinder, two pistons connected together and fitted to the
said cylinders, a stuffing box in the outer head of the larger cylinder, and a rod
common to both pistons passing through said stufhng box, substantially as herein
described
3. The combination, in an air compressor, of two single-acting cylinders of unequal
calibre, arranged in line with each other, and having heads at their outer ends, and
an air passage or conduit to form communication between said ends, two pistons
connected together, and fitting said cylinders, an inlet valve in the larger piston,
discharge valves between the outer end of the larger cylinder and the said passage
or conduit, inlet valves to the smaller cylinder, between the said cylinder and said
passage or conduit, and discharge valves at the outer end of the smaller cylinder,
substantially as herein described.
4. The combination, in an air compressor, of two single-acting cylinders of unequal
calibre, arranged in line with each other, being in free inter-communication with
each other, and with the atmosphere, at their inner or adjacent ends, and having
heads at their outer ends, a passage or conduit between the said heads, a discharge
valve in the head of the larger cylinder, between the said cylinder, and said passage
or conduit, an inlet valve in the head of the smaller cylinder between the said cylinder
and said passage er conduit, two connected pistons fitted to said cylinders, an inlet
valve in the larger piston opening towards the outer end of its cylinder, and discharge
valves in the head of the smaller cylinder, substantially as herein described.
NEWTON & SON,
Agents for the Applicant.