Improvements in the Cylinders of Air Compressors.
Year: 1889

page_text: Date of Application, 11th Jan., 1889
Complete Specification Left, 10th Oct., 1889-Accepted, 16th Nov., 1889
PROVISIONAL SPECIFICATION.
Improvements in the Cylinders of Air Compressors.
I THOMAS WALTER BARBER of Craiglea, Ulverston, in the County of Lancaster,
Engineer do hereby declare the nature of my said invention to be as follows
My improvements consist in means for more effectually abstracting the heat
generated by compression of the air during the process of compression.
To effect this I construct the compressing cylinder with a number of water tubes
either internally or externally cooled in either of the following ways.
For a single-acting cylinder the closed end has a number of tubes secured to it
opening into the cylinder at one end and to a valve chamber at the other end.
The tubes are surrounded with water. The piston has an equal number of
plungers secured to it and slightly smaller in diameter than the bore of the tubes,
which plungers reciprocate inside the tubes. On the back stroke air is drawn into
the cylinder through an inlet valve, and on the forward stroke is forced out by the
piston through the annular clearance spaces between the plungers and cooling tubes,
through the delivery valves; the greater part of its heat of compression being
abstracted thus before it leaves the cylinder and tubes.
This construction may be reversed; that is to say, instead of plungers the tubes may
be fixed to the cylinder cover as above and be carried through the piston with
suitable air tight packings round them and the water circulated inside the tubes;
the piston then compresses the air in the spaces around the tubes.
A third method is to fix the tubes to the piston and allow them to reciprocate
through packings in the cylinder cover, the piston ends of the tubes being closed the
water may be circulated within the tubes by fixed plungers sliding loosely within the
tubes which cause them to empty and refill with water at each double stroke of
the piston.
For double-acting cylinders the piston can be fitted with two sets of plungers as
described above, and provided with a set of water tubes for them at each end of
the cylinder. Or the tubes may run through the piston and be fixed to both end
covers, and the water circulated within them, or thirdly, the tubes may be fixed to
the piston and reciprocate through suitable packings in both end covers as described
above. In the last two cases the air is compressed in the spaces between the tubes.
The clearance spaces at the ends of the stroke may be filled by a small supply of
water, oil or glycerine.
A circulating pump may also be employed to keep the water in motion through or
around the tubes.
When plungers are used they may be made tubular, and by preference slightly
tapered (as also the tubes they work within) and water may be circulated through
them also to aid in cooling the air under compression.
Dated 11th Lonna 1980
THOMAS WALTER BARBER.
COMPLETE SPECIFICATION.
Improvements in the Cylinders of Air Compressors.
I, THOMAS WALTER BARBER of No. 15 Wykeham Terrace, Braybrook Road,
Hastings, in the County of Sussex, Engineer, (late of Craiglea, Ulverston, in the
County of Lancaster), do hereby declare the nature of my said invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement:—
My improvements consist in means for more effectually abstracting the heat

page_text: generated by compression of the air during the process of compression. To effect
this I construct the compressing cylinder with a number of water tubes either,
internally or externally cooled in either of the following ways. Fig. 1. shews one
application to a single acting cylinder A. In this plan the closed end B. has a number
of tubes C-C. secured to it, opening into the cylinder at one end and to a valve
chamber D at the other end. The tubes are surrounded with water. The piston E
has an equal number of plungers F F secured to it, slightly smaller in diameter than
the tubes and reciprocating, inside them. On the back stroke air is drawn into the
cylinder through the inlet valve G. which may be of any form, but is preferably
made of disc form to avoid clearance spaces, and being attached to the sleeve H.
through which the piston rod works, has a positive opening and closing movement
by the friction of the rod as it reverses its motion. On the forward stroke the air is
forced out by the piston through the annular clearance spaces between the plungers F
and cooling tubes C through the delivery valve J, the greater part of its heat of
compression being abstracted thus before it leaves the cylinder and tubes.
This construction may be reversed as Fig. 2. that is to say, instead of plungers
the tubes C may be fixed to the cylinder cover B, as above, and be carried through
the piston with suitable air-tight packings K. round them, and the water circulate
inside the tubes C. The piston then compresses the air in the spaces around
the tubes.
A third method is to fix the tubes C to the piston E as in Fig. 3. and allow
them to reciprocate through suitable packings K in the cylinder cover B. The piston
ends of the tubes being closed, the water may be circulated within the tubes by
employing the fixed plungers or displacers L sliding loosely within the tubes, which
cause them to empty and refill with water at each double stroke of the piston E.
For double-acting cylinders the piston can be fitted with two sets of plungers
as described above and provided with a set of water tubes and valves at each end
of the cylinder; a duplicate of Fig. 1. Or-the tubes may run through the piston
as Fig. 2. and be fixed to both end covers, and the water circulate within them.
Or thirdly, the tubes may be fixed to the piston as in Fig. 3. and reciprocate through
suitable packings in both end covers as described above. In the last two cases the air
is compressed in the spaces between the tubes. The clearance spaces at the end of the
stroke may be filled by a small supply of water, oil or glycerine.
A circulating pump may be employed to keep the water in motion.
When plungers are used as in Fig. 1 they may be made tubular and by preference
tapered, as also the tubes within which they work; and water may be circulated
through them also to aid in cooling the air under compression, the water being led
through the piston rod which can be made tubular.
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. In cylinders for compressing air or other gases the tubular surface cooler con-
struction as figured and described above for both single and double-acting cylinders,
by which the area of cooling surface is greatly augmented above that ordinarily
employed without the necessity for water injection.
2. The method illustrated in Fig. 1. for operating the inlet valve G by the
positive frictional movement of the piston rod within the sleeve H and stuffing
box I.
Dated this 9th day of October 1889
THOMAS WALTER BARBER.