IMPROVEMENTS IN STEAM PUMPS FOR RAISING OR FORCING FLUIDS
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by William Edward Garforth and
William Walker at the Office of the Commissioners of Patents, with
their Petition, on the 28th June 1873.
We, WILLIAM EDWARD GARFORTH, of Dukinfield, in the County of
Chester, and WILLIAM WALKER, of Newton Moor, in the same County,
Engineers, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN STEAM PUMPS FOR RAISING OR FORCING FLUIDS," to be as
follows:-
Our Invention relates to the now well known class of steam pumps or
of pumping engines which have valves that are actuated by the directly
acting pressure of steam, instead of by revolving crank shafts. In a
form of steam pump constructed previously to our said Invention the
piston of the steam cylinder was made of greater length than the stroke
and passages formed in the said piston, communicated alternately with
passages formed in the cylinder, and opening into the opposite ends of
the valve chamber, so that when the said piston neared cither end of its
stroke one of the passages in the piston communicated with the corre-
.

page_text: sponding pssage in the cylinder, and steam was thereby permitted to
flow from one end of the valve chamber through the said passages,
whereby the equilibrium of pressure on the two ends of the valve was
disturbed and the said valve was moved.
The object of the first part of our said Invention is to make such
pumps capable of working expansively, and to this end we form separate
passages for the inlet of steam to the steam cylinder, the ordinary
passages serving as exhaust ports only. Two recesses formed in the side
of the piston communicate each with opposite ends of the cylinder, and
as the said piston moves to and fro communicate in alternation with the
inlet passages for steam, and admit the steam to act alternately on the
two ends of the piston. By lengthening or shortening the aforesaid
recesses, we cause the steam to be "cut off" later or carlier, as may be
desired or found to be suitable.
We may make the valve such an easy fit in its chamber as that
sufficient steam to move the valve may enter the ends of the said
chamber by leakage past the ends of the valve, or we may fix a ring-
shaped partition in the valve chamber, and make the passages through
which steam flows to disturb the equilibrium as aforesaid, communicate
with the spaces on each side of the said partition. In such a case the
exhaust steam from the main cylinder would flow through comparatively
short eduction ports or passages into the end spaces of the valve chamber
and thence through suitable passages into a common exhaust passage or
pipe, or the exhaust steam from one end of the said chamber might flow
through a central passage formed in the valve to the other end of the
said chamber, the valve being arranged to close cach eduction port
before the piston reached the end of the cylinder.
In a steam pump constructed in accordance with a second part of our
Invention, we form separate passages for the inlet of steam to each end of
the valve chamber, and for the exhaust of steam thereform. Each exhaust
passage communicates at intervals with a separate recess formed in the
piston, and which serves to connect the said exhaust passage with a
passage leading into the main exhaust passage. The ends of the inlet
passages open into the cylinder and are alternately uncovered by the
piston as it moves to and fro. As the piston nears the end of its stroke
in either direction the end of one of the inlet passages is uncovered and

page_text: the steam is permitted to flow through the said passage into one end of
the valve chamber, and at the same time one of the aforesaid recesses
establishes a communication for the flow of steam from the other end of
the valve chamber into the main exhaust passage, and the pressure of
the entering steam acting on the valve imparts the necessary movement
thereto.