Year: 1899

page_text: We, JOHN GWYNNE, of 64, Cannon Street, in the City of London, Engineer,
and EDWARD WASHBOURN SARGEANT, of Hammersmith Iron Works, Hammer-
.smith, in the County of Middlesex, Engineer, do hereby declare the nature of this
invention to be as follows:-
-
This invention has reference to improvements in centrifugal pumps such as
are used for dredging purposes, an object being to obviate breakdowns caused by
the jamming of stones or the like between parts of the pump casing and the disc
or impeller.
In centrifugal dredging pumps as at present made it is usual to provide within
the volute-shaped passage, which surrounds the rotary disc or impeller, and is
of increasing diameter towards the outlet, a plate or partition known as and
hereinafter referred to as a stop," said stop being situated between the parts
of the said volute-shaped passage which are of the least and greatest diameters
respectively, with the object of directing the water to the outlet and preventing
its being driven round and round in the said passage. The stop has heretofore
been fixed, being generally cast with the pump and, the face of the stop being
necessarily close to the revolving disc or impeller it sometimas happens if the
material being dredged contains large stones, that such stones get jammed
between the revolving disc or impeller and the stop, breakage of one or the other
resulting.
Now, according to this invention the pump is provided with a stop adapted to.
yield when the pressure against it becomes excessive. In one arrangement the
stop is fixed radially on a shaft which projects through the side of the pump
casing and is there provided with a lever to which is connected the piston rod
of a cylinder containing elastic fluid such as steam or air, the arrangement being
such that when the piston rod is right out of the cylinder, the stop is in its.
working position with its face close to revolving disc or impeller, the stop being
preferably radial thereto, but that if a large stone should issue from the disc or
impeller just as it is passing the stop, the stop will be caused to turn about
the axis of its shaft so as to allow the stone to pass; the stop in moving will
force the piston rod into its cylinder against the pressure of the elastic fluid,
which, directly the stone has passed again. forces out the piston and replaces the
stop in its working position. Instead of an elastic fluid-containing cylinder,
one or more strong spiral springs may be arranged on and connected with the.
shaft of the stop and adapted to bear against fixed abutments so as to normally
hold the stop in position but to allow it to yield when necessary; the springs
· 0.71

page_text: may be adjustable if desired. Or, in place of the springs, the shaft may be
provided with a weighted lever arranged to act in a similar manner.
Dated this 29th day of March 1899.
For the Applicants,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Chartered Patent Agent.
Improvements in Centrifugal Pumps.
We, JOHN GWYNNE, of 64, Cannon Street, in the City of London, Engineer,
and EDWARD WASHBOURN SARGEANT, of Hammersmith Iron Works, Hammer-
smith, in the County of Middlesex, 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: —
This invention has reference to improvements in centrifugal pumps such as
are used for dredging purposes, an object being to obviate breakdowns caused by
the jamming of stones or the like between parts of the pump casing and the disc
or impeller.
<<
In centrifugal dredging pumps as at present made it is usual to provide within
the volute-shaped passage, which surrounds the rotary disc or impeller, and is
of increasing diameter towards the outlet, a plate or partition known as and
hereinafter referred to as a stop," said stop being situated between the parts
of the said volute-shaped passage which are of the least and greatest diameters
respectively, with the object of directing the water to the outlet and preventing
its being driven round and round in the said passage. The stop has heretofore
been fixed, being generally cast with the pump and, the face of the stop being
necessarily close to the revolving disc or impeller, it sometimes happens if the
material béing dredged contains large stones, that such stones get jammed
between the revolving disc or impeller and the stop; breakage of one or the other
resulting. Now, according to this invention the pump is provided with a stop
adapted to yield when the pressure against it becomes excessive.
Referring to the accompanying drawings Figs. 1 and 2 are views at right
angles to each other illustrating one arrangement of stop applied to a centrifugal
pump, part of which is indicated in dotted lines, in accordance with this invention.
In this case the stop 1 is fixed radially on a shaft 2 which projects through the
side of the pump casing 3 and is supported in bearings 4, 4ª, the bearing 4 being
formed with a stuffing box and gland through which the shaft 2 extends. 5 is
a lever which is connected by a rod 6 to a trunk piston 7 working in a cylinder 8
containing elastic fluid, such as steam or air admitted thereto through the pipe 9.
When the piston rod is in the position shown, the stop 1 is in its working posi-
tion as shown in full lines with its face close to the revolving disc or impeller
of the pump which rotates in the direction of the arrow, the stop being preferably
radial to said disc or impeller. If a large stone should issue from the disc or
impeller just as the stone is being carried past the stop, the stop will be caused
to turn together with its shaft about the axis of the latter so as to allow the
stone to pass; the stop in moving will force the piston 7 into its cylinder against
the pressure of the elastic fluid, which, directly the stone has passed will again
force out the piston and replace the stop in its working position.

page_text: Figs. 3 and 4 are similar views to Figs. 1 and 2 illustrating a modification,
wherein instead of an elastic fluid-containing cylinder 8, one or more strong
spiral springs 10 are arranged on and connected with the shaft 2 and adapted to
bear against fixed abutments so as to normally hold the stop in position but to
allow it to yield when necessary; the springs may be adjustable if desired.
In the arrangement shown there is a spring 10 upon each end portion of the
shaft 2, the inner end part of each spring being inserted in a transverse hole 2*
in the shaft, whilst the outer end of each spring passes through a hole 4* formed
in each of the bearings 4, 4ª, each of which is in the form of a tubular boss as
shown. Each boss has a recessed end into which extends the corresponding end
portion of the shaft; 11, 11 are arms fixed upon the shaft and working between
abutments 12 within the recessed ends of the tubular bosses, which abutments
serve to limit the movement of the stop. Escape of water is prevented by cover
plates 13. Figs. 5 and 6 are similar views of a further modification wherein the
shaft is provided with a weighted lever 14 arranged to normally rest in contact
with a wooden block or abutment 15 carried by a bracket 16 upon the pump
casing. 17 is a chain shackled to the bracket 16 and to the lever 14 so as to
limit the movement of the latter and of the stop when thrown back.
Having now particularly described and ascertained the mature of the said
invention and in what manner the same is to be performed we declare that what
we claim is:-
1. A centrifugal pump wherein the stop, plate or partition by which water
being passed through the pump is directed to the outlet thereof is adapted to
yield when the pressure against it becomes excessive, substantially as described.
2. A centrifugal pump wherein the stop, plate or partition by which water
being pumped is directed to the outlet thereof is constructed and arranged sub-
stantially as described with reference to and illustrated in Figs. 1 and 2, OP
Figs. 3 and 4, or Figs. 5 and 6 of the accompanying drawings.
Dated this 21st day of December 1899
For the Applicants,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Chartered Patent Agent.