IMPROVEMENTS IN PUMPS
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by Thomas Wood Gray at the Office.
of the Commissioners of Patents, with his Petition, on the 2nd December
1864.
I, THOMAS WOOD GRAY, of No. 1, Margaret Street, Limehouse, in the
County of Middlesex, Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN PUMPS," to be as follows:-
The first part of this Invention relates to improvements in that class of
pumps known as Downton's pumps, and for which a Patent was granted to
Jonathan Downton on the 19th July 1825 (No. 5221). This class of pump,
as now usually constructed is composed of three pistons or buckets, from each
of which a rod rises to a cross head or slide which works in suitable guides,
and each slide has a slot formed in it in which is received a cam surface
carried by a crank, a separate crank and cam surface being employed for each
slide, and the three cranks being .all carried by one axis. All the slides thus
have motion transmitted to them on the rotation of the axis. My improve-
ments consist in applying guide rollers to the working surfaces of the slides
above mentioned in order that the slides may move to and fro with less
friction than heretofore, and also in applying a roller or rollers to one or more
parts of the working surfaces of the cams that act on the slides, in order that
the cams may give motion to them. with less loss from friction than heretofore.
In this description of pump as now constructed, the three rods which pass to
the three pistons or buckets are placed side by side, and the rod which passes

page_text: to the lowest piston passes through the two pistons above it, these two pistons
being provided with stuffing boxes through which the rod passes; and the rod
that passes to the central piston passes through the upper piston, this piston
being provided with a second stuffing box to allow of this. These stuffing
boxes have heretofore been placed on the upper surface of the pistons, so
leaving but a very small space for attaching the valves. Now according to
my Invention I place the stuffing boxes on the under side of the pistons, and
by this means obtain an increase of space on their upper surfaces that is
available for fixing the valves, and also more space for forming the water
passages.
Heretofore pumps have in some cases been constructed of two double-acting
pump3, the barrels or cylinders of which are cast or placed side by side with a
valve box or chamber between them. Now, in constructing pumps of this
description I form the valve chamber of a height equal to the height of the
cylinders or projecting slightly below them, to retain water on the top of the
valves and divide it into two compartments by a vertical partition passing
from one cylinder to the other. At the bottom of each compartment is placed
an inlet valve and at the top an outlet valve; from each compartment an
opening is formed into each cylinder, one opening being made into the top of
one cylinder, and the other into the bottom of the other cylinder, and these
openings are made so that there is one opening from the top and one from the
bottom of each cylinder. The pistons of the cylinders are actuated in such
manner that when one is rising the other is descending, by which means water
will simultaneously be discharged from both cylinders into one of the compart-
ments of the valve chamber and so out through the exit valve at its top, and
at the same time water will be drawn into the cylinders on the opposite sides
of the pistons from the other compartment. On the reverse stroke of the
pistons the reverse action will take place, the water being forced from both
cylinders into the compartment of the valve chamber from which water was
before being drawn, and being drawn into the cylinders from the compart-
ment into which it was before being forced. I also combine together two
double-action pumps in the following manner :-The two cylinders or barrels
are placed in a line with each other, with the piston of each cylinder con-
nected to a piston rod that works in both cylinders. The valve chamber I
form at one side of the cylinders, either in one piece with or separate from them,
the chamber being of a height equal to or slightly greater than the height of
both cylinders. I divide the chamber longitudinally into two compartments
by a partition as in the arrangement just described, and as in that arrange-
ment an inlet valve is placed at the bottom of each compartment, and an

page_text: outlet valve at the top of each compartment, and passages are formed from
the compartments of the valve chamber; so that as in the former arrange-
ment water may on one stroke of the piston be simultaneously forced from
both cylinders into one compartment of the valve chamber, and at the reverse
stroke into the other compartment.
In constructing pumps for mining purposes, a number of pumps con-
structed of two cylinders in a line with one another, and with the pistons
connected to one rod as above described, may be connected together one
above the other, the pistons of all the pumps being connected to a common
piston rod which passes down through all the cylinders. In this arrangement
the exit valves at the top of one valve chamber will form the inlet valves of
the valve chamber above it, and thus the water that is raised by one pump
will be delivered to the pump above it.