An Improvement in Relief Valves for Feed Pumps.
Year: 1895

page_text: Date of Application, 26th Nov., 1895
Complete Specification Left, 8th Feb., 1896-Accepted, 14th Mar., 1896
PROVISIONAL SPECIFICATION.
An Improvement in Relief Valves for Feed Pumps.
We, EDWARD BONAR CAIRD, and THOMAS JAMES RAYNER, both of
777 Commercial Road, Limehouse, in the County of London, Engineers and
Copper Smiths, do hereby declare the nature of this invention to be a
follows:-°
This invention relates to the relief valve for a feed pump, allowing free escape
of water from the discharge pipe of the pump when the usual passage for feed
water to the boiler is more or less closed. For this purpose, we provide a valve
box, in which there is a shut off valve having on its stem a heavy vertical plunger
fitting a cylindrical cavity formed in the valve box. The upper part of this cavity
communicates with the boiler that is fed by the pump, so that the boiler pressure
is always acting on the plunger tending to close the shut off valve. By so
proportioning the areas of the valve and plunger, that the boiler pressure acting
on the plunger together with the weight of the plunger and valve exceeds by a
certain amount the pressure which tends to open the valve when the feed is free,
the valve under ordinary conditions remains closed. But when the feed passage
to the boiler is throttled so that the pressure in the discharge pipe of the feed
pump is increased beyond the pressure that keeps the valve closed, then the valve
opens and allows escape from the feed pipe.
It is preferred to pass through a stuffing box at the top of the valve box a rod
the lower end of which bears on the top of the plunger.
By more or less loading this rod the pressure closing the valve can be varied.
Dated this 26th day of November 1895.
ABEL & IMRAY,
Agents for the Applicants.
We, EDWARD BONAR CAIRD, and THOMAS JAMES RAYNER, both of
777 Commercial Road, Limehouse, in the County of London, Engineers and
Copper Smiths, 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 relates to the relief valve for a feed pump, allowing free escape
of water from the discharge pipe of the pump when the usual passage for feed
water to the boiler is more or less closed. For this purpose, we provide a valve
box of which the accompanying drawing is a vertical section.
A is a shut off valve having on its stem a heavy vertical plunger B fitting a
cylindrical cavity C formed in the valve box. The upper part of this cavity
communicates by a pipe D with the boiler that is fed by the pump, so that the
boiler pressure is always acting on the plunger B tending to close the shut off
valve A. By so proportioning the areas of the valve A and plunger B, that the
boiler pressure acting on the plunger together with the weight of the plunger and

page_text: valve exceeds by a certain amount the pressure which tends to open the valve
when the feed is free, the valve under ordinary conditions remains closed. But
when the feed passage to the boiler is throttled so that the pressure in the
discharge pipe of the feed pump is increased beyond the pressure that keeps
the valve A closed, when the valve opens and allows escape from the feed pipe
by the passage G to the passage H, whence the water can return to the suction
supply of the feed pump.
It is preferred to pass through a stuffing box at the top of the valve box a rod L
the lower end of which may be pressed on the top of the plunge B, to move it in
case of its sticking.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
A relief valve for a pump feeding a boiler so arranged as to be subject to the
steam pressure in the boiler substantially as and for the purpose set forth.
ABEL & IMRAY,
Agents for the Applicants.
ABEL & IMRAY,
Agents for the Applicants.