IMPROVEMENTS IN PUMPS AND PUMP AIR VESSELS
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by Stephen Holman at the Office of
the Commissioners of Patents, with his Petition, on the 2nd November
1866.
-1, STEPHEN HOLMAN, of 90, Cannon Street, London, E.C., in the County
of Middlesex, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN PUMPS AND PUMP AIR VESSELS," to be as follows:-
According to my improvements I obtain a continuous discharge of water or
other fluids from pumps by means of a double piston, or two detached pistons
or buckets attached to one rod and working in one cylinder, and two detached
valves placed in any convenient position in relation thereto, whereby uniformity
of action and working strain is maintained, and the pump is produced at a
comparatively little cost.
My improvements are effected in the following manner :-I provide a
pump,, cylinder,
or barrel having a central orifice, which said orifice may be
either used for the admission of water or other fluids into the pump, or for the
discharge of the fluids from the pump; whether the central orifice shall be
the inlet or outlet will depend upon the determined arrangement. of the
piston valves and the detached valves which I will hereafter explain.
I will now describe the action of a vertical pump according to my Invention.
To the cylinder or barrel aforesaid a cover is fitted having a stuffing box
through which the pump rod passes, two pistons (or buckets). are secured to
the pump rod placed at a proper distauce from each other to permit the

page_text: lower piston to traverse any determined length of stroke between the central
orifice and the bottom of the pump cylinder, and the upper piston to traverse
a precisely similar length of stroke between the central orifice and the
top of the pump cylinder, thus one piston works below the central orifice
and the other above it; the piston valves may be so arranged that the lower
piston will draw the water or other fluids into the pump in its downward
movement and the upper piston in its upward movement, so that a constant
ingress through the central orifice will be effected by the alternate action of
the pistons; on the other hand the valves may be so placed that the lower
piston will discharge the fluid through the central orifice in its upward
movement and the upper piston in its downward movement, thereby effecting
a constant egress through the central orifice by the 'alternate action of the
pistons. It will be understood that each piston is provided with a disc or
other suitable valve; a detached valve is also placed in near proximity to each
piston, and the detached valves may be operated by the pistons either as
suction or delivery valves, depending as aforesaid upon the determined
arrangement of the inlet and outlet passages, when the detached valves are
used as suction valves they will open towards the pistons as they (the
pistons) reciprocate in the cylinder, in which case the fluid will not be drawn
in through, but forced out through the central orifice, and will be drawn into
the pump at each end of the cylinder or barrel through inlet passages in which
the detached valves are conveniently placed, or the detached valves may be
placed within the cylinder itself at top and bottom just beyond the range of
the pistons. It is to be understood that there is a lower piston and a
detached valve, and an upper piston and a detached valve. At the upward
stroke of the pump the valve of the lower piston and the detached valve above
the upper piston oppose themselves and close against each other, so that the
lower piston as it approaches the upper detached valve, which is closed on a
fixed seating, will force out and discharge the fluid between them through the
Central orifice; again, the valve of the upper piston and the detached valve
below the lower piston also oppose and close against each other, so that at
the down stroke of the pump, as the upper piston approaches the lower
detached valve which is now closed on a fixed seating, the fluid between them
will be forced out and discharged through the central orifice, thus a constant
discharge of the fluid is effected by the alternate action of the pistons. When
either of the pistons is forcing the fluid through the central orifice, according
to the arrangement just above described, its own valve being closed a 'vacuum
is formed behind it, so that it draws the fluid through the detached valve
nearest to it at the same time, thus each piston alternately performs the work

page_text: of; an ordinary single-acting force pump, and a double-action pump, is thus
accomplished in a single cylinder or barrel.
I have hitherto described my Invention as having two pistons in operation,
indicating that they are in two parts, it is quite practicable, however, and in
the case of very short stroke pumps it will be even advantageous, to make
what I have described as two pistons in one piece, viz., an elongated piston
having the two ends enlarged and made to fit the cylinder above and below
the central orifice.
:
Although in this Specification I have given a description of a vertical
pump,
I make also horizontal pumps without departing from the principle of
my Invention herein set forth.
My Invention, further consists in an improved construction of air vessel
alapted to the pump I have herein described and other pumps, viz., I form.au
outer casing and insert.therein a tube considerably smaller in diameter than the
interior of the case, the upper end of the tube is secured to the casing, and
rendered air-tight between the casing and the tube in the usual manner, the
lower end of the tube being free from the casing, so that the fluid may enter
the space at the bottom between the tube and the air vessel case; thus when
the pump forces the water into the air vessel at the bottom the air which
previously filled the space between the air vessel case and the tube at the
ordinary atmospheric pressure will be compressed by the water as it is forced
by the pump up through the air vessel tube, and the air contained between
the tube & the case will decrease and increase in bulk according as the
action of the pump may increase or decrease the areal pressure. The object
and use of the inner tube in air vessels hitherto constructed of this des-
cription has been to permit the passage of the fluid pp through the tube to
the point of discharge only. In my Invention, however, I place the air
vessel in connection with the two discharge passages of double-action pumps
so that the water or other fluid may pass either up or down the air vessel tube,
and be discharged either at the top or bottom of the air vessel; to accomplish
this I make a water passage communicating between the top of the pump and
the top of the air vessel tube, thus the water that is forced into the common
discharge pipe above the air vessel by the upper piston or uppèr side of a
piston, as the case may be, will act upon the air in the vessel by transmitting
its pressure down through the tube according to the well-known law that
fluids press equally in all directions; therefore, although the fluid is being
driven upwards its pressure will be exerted upon all the surface exposed to its
influence, and, on the other hand, when the discharge of the fluid is made at
the bottom of the air vessel the upper piston, or side of a piston, as the case

page_text: may be, will force its portion of water down through the tube to the outl.t
pipe, and the lower piston or side of a piston will, simply force its portion of
water out through the same outlet pipe under the influence of the compressed
air in the air vessel; by this arrangement, therefore, the air vessel is in
'constant action when the pump is in motion, and it may be placed by
the side of the pump cylinder as easily as above it, because the fluid is
permitted to act upon the air in the vessel both from the top and bottom,
from the top of the pump down through the tube, and from the bottom of
the pump direct to the bottom of the air vessel. It is' to be. understood
that the water passes through the tube of the.air vessel in one direction only,
and that the water or other fluid discharged by each of two pistons, or each
side of one piston, meet either above or below the air vessel, according as the
determined position of the outlet pipe is at the top or bottom..
:
My Invention further consists of a very simple method of securing the
several portions of the small force pumps together, viz., I place my air vessel
as-bërein described by the side of the pump-cylinder, and embrace their ends
by means of seperate top and bottom chambers; I then secure the whole
together entirely by a single bolt conveniently placed longitudinally between
the air vessel and pump-cylinder; thus by simply releasing one screw every
part of the pump is immediately accessible for examination and repair.
My Invention further consists of an improved jet or spreader for the
ultimate distribution of water from the pumps when used as fire engines or
for similar purposes, viz., I form grooves in the spreader which is brought
into contact with the water as it issues' from the pump jet piece, and the
spreader having the grooves may be made circular in form or otherwise, and
the grooves made to radiate from the centre to the extreme edges of the
spreader may be made of various sizes to effect a finer or coarser subdivision
of the stream at pleasure; when various sizes of grooves are made the spreader
is made to rotate on an axis in order to permit any required portion of the
circular or disc-shaped spreader to be brought into contact with the issuing
stream or jet, the grooves therefore are intended to have the effect of holes but
with greatly diminished friction in the discharge of the fluid; the grooves are
adapted to spreaders generally having a flat surface with great facility and at
little cost.