Improvements in Reciprocating Pumping Machinery for Exhausting or Compressing Air, Vapor, or Gas."
Year: 1893

page_text: COMPLETE SPECIFICATION.
Improvements in Reciprocating Pumping Machinery for Exhausting
or Compressing Air, Vapor, or Gas."
I, JOHN NORMAN SPENCER WILLIAMS, of the London Road Iron Works,
Glasgow, in the County of Lanark, North Britain, 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, that is
to say :-
My said invention has for its object to construct reciprocating pumping machinery
for exhausting or compressing air, vapor, or gas, in an improved manner so as to
obtain increased economy and efficiency in working, by diminishing the bad effects
due to re-expansion of the air, vapor, or gas in "clearance" spaces at the ends of
the pump cylinder.
In carrying out my invention I employ a special arrangement of positively
actuated Corliss oscillating inlet and outlet valves for the pump cylinder which are
opened and closed at particular times, and I form shallow grooves in the inner sides
of the cylinder at each end through which grooves part of the entrapped air passes
to the other side of the piston thereby allowing the suction to act fully as the
piston moves away from the end, whilst the air passing through the grooves
supplements the air on the other side of the piston and about to be compressed.
And in order that my said invention and the manner of performing the same may
be properly understood I hereunto append a sheet of explanatory drawings, to be
hereinafter referred to, and showing pumping machinery as made with my
improvements.
Figures, 1, 2, and, 3, of the drawings are diagrammic views of parts of the pump
and Figure, 4, is a longitudinal vertical section of the entire machine. In these
drawings the same reference letters are used to mark the same or like parts
wherever they are repeated.
Referring to Figure, 1, of the drawings the piston, A, being at one end of its
stroke, the inlet valve, B, at that end is on the point of opening, the outlet valve, C,
is closed, and the inlet valve, D, and outlet valve, E, at the other end are closed.
Grooves or passages, G, are formed in the inner sides of the cylinder, J, and made
just long enough to communicate with the spaces on opposite sides of the piston, A,
when it is at the end of its stroke. The compressed air in the clearance space
between the piston, A, and the end of the cylinder, J, expands and part of it passes
by the grooves, G, to the space on the other side of the piston, A, momentarily
equalising the pressure in both spaces and reducing the pressure in the clearance
space and thereby enabling the piston to do effective suction work at the beginning
of its stroke away from the end of the cylinder. On the piston, A, beginning its
stroke the communication through the grooves, G, is stopped their inner ends being
covered by the piston, the inlet valve, B, is opened and through it air is drawn
from the vessel being exhausted. When the piston, A, arrives at half stroke
(as shown in Figure, 2,) the inlet valve, B, is fully opened and the outlet valve, C,
at the same end closed, whilst the inlet valve, D, and outlet valve, E, at the other
eud are still both closed. On the piston, A, moving further the outlet valve, E, is
opened and through it the air or gases are forced. Before however the piston, A,
quite reaches the end of its stroke (shown in Figure, 3,) and before communication
takes place through grooves, K, between the spaces on opposite sides of the piston
the inlet valve, A, and outlet valve, E, are closed; whilst on the piston reaching
the end of its stroke the same action occurs as that described with reference to
Figure, 1, but in the opposite direction.
The machine as constructed and arranged for carrying out my invention is

page_text: shown in Figure, 4, and parts not herein described are to be understood as being of
ordinary construction. The inlet and outlet valves, B, C, D, and, E, are of the
oscillating type and are made to cover and uncover ports, L, in the valve chambers
and communicating with the interior of the cylinder, J. The inlet valves, B, and, D,
are worked respectively by reds, M, and, N, one end of each of which is attached
to a wrist plate, 1', rocking on a stud, Q, on the side of the cylinder, J, the plate
being worked as usual with Corliss valve gear. In a similar way the outlet
valves, C, and, E, are respectively connected by rods, S, and, T, to another wrist
pfate, V, rocking on the same stud, Q, and similarly driven. The piston of the
pump cylinder is represented as directly driven by a steam cylinder, W, the joint
piston rod, X, being connected to a crank shaft having on it a fly wheel, Z.
When the machine is to be used for compressing air or other gas the action of
the valves remains the same, the outlet valves being however connected to the vessel
into which the air is to be compressed.
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 reciprocating pumping machinery for exhausting or compressing air, vapor,
or gas, constructing the inner sides of the pump cylinder with grooves (G, K) at
the ends arranged to communicate with the cylinder space on opposite sides of the
pisten when it is at either end of its stroke, substantially as and for the purposes
hereinbefore described.
2. The combination of parts constituting the improved exhausting or compressing
cylinder with its positively actuated oscillating valves and end grooves substantially
as hereinbefore described.
Dated this Seventeenth day of October 1893.
EDMUND HUNT,
Applicant's Agent.