Improvements in Pumps of a Reciprocating Character used in con- nection with the Compressing or Exhausting of Air or other Gases or for Pumping Water or Water and Gas together, or any Liquids and Gases.
Year: 1898

page_text: Date of Appleation, 12th Sept., 1898
Complete Specification Left. 12th June 1899-Accented 29th July 1800
codon was fundaddy in a
Complete Specification Left, 12th June, 1899-Accepted, 29th July 1800
PROVISIONAL SPECIFICATION,
Improvements in Pumps of a Reciprocating Character used in con-
nection with the Compressing or Exhausting of Air or other
Gases or for Pumping Water or Water and Gas together, or any
Liquids and Gases.
I, JAMES CARSON, of 50, Clarinda Park East, Kingstown, Co. Dublin, Civil
Engineer, do hereby declare the nature of this invention to be as follows:-
The object of this invention is to increase the efficiency of such machines more
especially in connection with the compression of gases by eliminating the
clearance capacity at each end of the stroke, or more particularly in the single
acting type in which the whole work of compressing is effected on one face of
the piston. In all ordinary types of pumps it is necessary to leave a space between
the end cover and the face of the piston when at the extremity of its stroke, and
it is of the utmost importance that this clearance should be as little as possible
in all air or gas compressing machines to give the greatest efficiency as the gas
compressed into the clearance space expands on the return stroke and occupies
a large part of the capacity of the cylinder whereby the inflow of the gas before
compression on the filling or suction stroke is checked by the expansion of the
compressed gas left in the cylinder at the completion of the compressing stroke
thereby resulting in the expenditure of considerable power without producing
useful work. The chief object of this invention is to practically eliminate the
aforesaid clearance and thereby greatly increase the efficiency of the machine
without increasing the effort required under ordinary circumstances-and
thereby effecting a considerable saving in power.
The method whereby this object is attained is as follows;-
In a machine for pumping gas in which the said gas is admitted into a cylinder
above at or below atmospheric pressure and then compressed by a moving piston
to any given pressure moved or driven by any motive or hand power in the
usual way and discharging the gas so compressed into a reservoir or other
receptacle or through a nozzle nozzles or otherwise for ventilating purposes-
blowing engines-gas compressing plant-for mineral water manufacture or for
any other purpose in which it is necessary to admit air or gas of a low pressure
into a cylinder and there compress it to a higher pressure for any purpose what-
soever.
The end of any compressing cylinder is fitted with a valve or disc part of which
is made of the same diameter as the cylinder and consequently the same diameter
as the piston when the piston is at the extreme end of its stroke its face and
the face of the valve are in touch with each other hence there is no clearance
whatsoever but the valve is made with a head or collar a little larger than
the bore of the cylinder the cylinder end at this part being enlarged to accomo-
date the increased diameter of the head-thereby the end of the cylinder proper
becomes a seat against which the head or collar seats itself when the piston is
moved a little on its return stroke,

page_text: The space behind the valve-that is between its outer end or back and the
cover is sufficient to permit the valve to be forced back by the compressed gas to
a short distance beyond the point where the piston rests at the completion of
its stroke hence there is no need for absolute accuracy in arranging the length
of the stroke other than that used in connection with ordinary practice.
The aforesaid valve is guided by a backward extension in a short cylinder
formed in the cover and may or may not be kept against the end of the cylinder
which is its seat by a spring or springs. The space behind the valve and between
it and the cover forms a small reservoir through which the compressed gas
passes on its way to the outlet. The centre part of the aforesaid valve may be
arranged to be the inlet or suction valve for the admission of the air or gas into the
cylinder before compression being arranged as follows. The centre part of the
valve and its backward extension is bored through and a valve fitted to same
with its head seated against a face recessed into the face of the larger or outlet
valve the end cover being bored through and the backward extension of the large
valve packed to prevent the compressed gases from escaping-but by preference
the suction or inlet to the cylinder is provided for by valves placed at the sides
or any other part of the end of the cylinder independently of the large or outlet
valve.
The outlet from the chamber between the back of the large valve and cover is
taken off from any part of the cover available and within the said chamber a
coil of piping may be arranged for circulating water to cool the gases as they
are compressed.
It is obvious that the above improvements will enable the whole capacity of the
cylinder to be utilized as no clearance exists and the whole pressure when dis-
charged from the cylinder is exerted against the back of the valve-the effort
of the piston in compressing the gas can only be a little above the pressure behind
the valve, hence immediately the pressure in the cylinder becomes slightly greater
than that behind the valve-the valve is raised or pushed off its seat and the
compressed gas passes from the cylinder past apertures arranged around the part
of the valve that fits the cylinder into the chamber behind and away into the
reservoir.
It is evident that the whole contents of the cylinder will be discharged giving
practically 100 per cent, efficiency. When compressing a gas to discharge into a
lower pressure the discharge valve would be arranged with an extension through
the cover and a cylinder & dash piston loaded to the pressure required-and as
this piston would have only an infinitesimal movement there would be no loss of
power the same effect could be obtained by springs.
But as most compressing machines are used for storing pressure the simple
arrangement of valve as a discharge valve with chamber behind it would be
sufficient.
In the case of pumping water or other liquids the head is sufficient for all
purposes to properly balance the valve.
The operation of a pumping machine with its discharge valve arranged as a
moveable end which is in actual contact with the piston at the end of the stroke is
as follows:
-
The suction stroke of the piston in the cylinder draws in air or gas to com-
pletely fill it and the action of the piston on the return stroke compresses the
air into a smaller space and to a higher pressure-immediately the pressure in
the cylinder becomes a little higher than that behind the valve the valve is
slightly unseated and the whole contents of the cylinder are discharged. At the
end of the stroke the piston is in actual contact with the valve which is unseated
-immediately the piston begins its outward or suction stroke the valve reseats
itself and as the piston leaves it a vacuum is formed at the commencement of the
suction stroke—another charge is then drawn in by the inlet valve and the pump
commences another compression.
Hence we have an entire elimination of clearance and consequently a full result

page_text: from the power applied and practically the zenith of efficiency-with no loss of
power and no disability to work at any speed-being a practicable method of
working any pumping machine without clearance between piston face and cylinder
end.
Improvements in Pumps of a Reciprocating Character used in con-
nection with the Compressing or Exhausting of Air or other
Gases or for Pumping Water, or Water and Gas together, or any
Liquids and Gases.
I, JAMES CARSON of Belmont, Solihull, Warwickshire, formerly of 50, Clarinda
Park East, Kingstown, Co. Dublin Civil Engineer do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement;-
The nature of this invention is for the purpose of eliminating clearance between
the face of a piston & cylinder cover whereby the whole of the contents of the
cylinder is discharged at the end of each stroke-thereby increasing the efficiency,
and enabling a greater amount of useful work to be done which is now lost
due to the space between the piston & cylinder cover retaining a portion of the
contents more especially in connection with the work of compressing air in
which the clearance space contains a large body of the highest pressure air or gas
which by its expansion on the return stroke results in a serious loss before the
drawing in of a fresh charge commences whereby only a part of the capacity of
the cylinder is utilized to perform useful efficient work and in the case of pump-
ing water or other liquids the efficient lift of said pump to raise it into the
cylinder is seriously affected whereby a partial instead of a whole charge is the
product of each stroke.
In an engine used for compressing air or other gas or for pumping liquids
the clearance space between the piston P & cylinder cover is eliminated the
piston at the completion of each stroke being in actual contact with a valve V
which covers the full area of the cylinder end-the back part of the valve may
be elongated and arranged as a piston to fit into a corresponding recess made in
the outer cover whereby a dash pot arrangement is possible to act as a buffer in
the event of the engine losing its charge-the object being to mitigate the noise
incidental to the rapid unseating of a valve due to a rapid loss of pressure on
one side or to avoid a similar noise when first beginning to compress or. pump.
The general arrangements of the invention are as follows:-In an engine for
compressing air or gas or pumping water the cylinder is bored through in the
ordinary way but in place of the ordinary end cover the end of cylinder is closed
by a valve V of the full area of the cylinder à portion of said valve projects into
the cylinder a little way being an amount a little more than the required lift
hence when the piston P is at its fullest stroke and the valve V in contact with
the face of the piston a portion of the valve is still a little within the bore of the
cylinder-but part of this cylindrical portion of the valve within the cylinder is
cut away sufficiently to permit the passage of the air, gas, or fluid through
between & past the cylinder bore and that part of the valve V projecting into
the cylinder the part of the valve beyond the end of the cylinder is made a
little larger than the bore of the cylinder the cylinder end acting as a seat against
.

page_text: which the larger part of the valve seats itself on the inward stroke-thereby
cutting off the bore of the cylinder from the outside of the valve which is on the
pressure or delivery side.
The suction or inlet valves I are arranged independently of the delivery valve V
and may be arranged in any suitable way but preferably they are made to open
into the cylinder immediately inside the face of the delivery valve to enable the
cylinder to begin to fill immediately the piston is clear of the inside face of the
delivery valve.
The suction valve may be arranged in the centre of the delivery valve and
carried beyond the outer cover the delivery side of valve V being separated from
the suction or outer air by a packing ring working within a cylinder as an air-
tight interceptor but by preference the delivery & suction valves are arranged as
before mentioned.
In the drawing 1 represents the piston, V the delivery valve, S the spring
which exerts a slight pressure to keep V on its seat, R is a space between the
valve V and the cover C which communicates with the outlet O by means of the
holes H. I is the inlet valve. The action of the pump when at work is as
follows: In an engine used for compressing air or gas the valves being arranged
as afore mentioned the piston l' moves up towards the valve V which may be
kept up to its seat by the spring S for the purpose of returning the valve V to
its seat at starting though this is not absolutely necessary.
When the piston
commences its compressing stroke (in actual working) the pressure rises imme-
diately the pressure within the cylinder preponderates over that behind the
valve V the valve is slightly unseated and remains unseated during the period
of compressing, the air or gas passing into the space R and thence to the outlet 0.
When the piston is near the completion of its stroke the pressure behind and
before the valve is in equilibrium hence the action of the spring tends to return
the valve V to its seat and thus when the piston is at the end of its stroke the face
of the valve V and the piston P are in contact and the valve is a little way from
its seat consequently no clearance exists except the small amount around the
outer edge of the valve V within the cylinder-hence the engine is practically
without clearance. At the commencement of the return stroke the cylinder is
practically empty hence it can be completely filled-the next stroke drives out
the whole contents and so on the engine-having a practical efficiency of dis-
charging the whole of its contents at every stroke. The self same set of conditions
pertains when the engine is used for pumping water or other liquid.
The drawing shows a single acting pump but obviously a similar set of con-
ditions can be arranged in connection with a double acting pump except that a
hole for the piston rod arranged with a suitable non-frictional gland in the
valve V will permit the aforesaid conditions to be fulfilled, similarly to the single
acting pump.
The outlet O may of course be in any part of the cover Ċ.
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;-
A valve which enables an engine or pump to work with the minimum of
clearance between the piston & cover as hereinbefore described whereby a higher
duty and greater efficiency is attainable.
D
T
1000