Improvements in Hydraulic Working Valves.
Year: 1898

page_text: Date of Application, 19th July, 1898
Complete Specification Loft 10th Ann 1900 Aesentad
20th Mov
1900
PROVISIONAL SPECIFICATION.
Improvements in Hydraulic Working Valves.
I, FRANK WALTER SCOTT, of 44, Christian Street, Commercial Road, in the
County of London, Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to hydraulic working valves of the kind described in the
Specification of former Letters Patent No. 14563 of 1891 the object of the present
invention being to prevent accidents, when such valve is used in connection with
lifts, cranes or the like, which might occur owing to the failure of pressure in
the hydraulic main.
According to my invention I arrange in combination with the inlet and exhaust
valves a third valve which, so long as the pressure is maintained in the hydraulic
main, remains open but which, when little or no pressure exists in the main,
closes to prevent the water on the pressure side of the ram cylinder from flowing
back into the main under the pressure upon the ram. I make a small passage
through the exhaust valve for equalizing the pressure above and below the said
valve
By the use of my invention a load which has been raised by the pressure water
will be held up in case the pressure of the main is suddenly lost and can then
be gradually lowered so that no actual accident can arise.
Total this 10th
T.... 1903
G. F. REDFERN & Co.,
4, South Street, Finsbury, London,
Agents for the Applicant.
Improvements in Hydraulic Working Valves.
I, FRANK WALTER SCOTT, of 44, Christian Street, Commercial Road, in the
County of London, 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:
-
My invention relates to hydraulic working valves of the kind described in the

page_text: Specification of former Letters Patent No. 14563 of 1891 the object of the present
invention being to prevent accidents, when such valve is used in connection with
lifts, cranes or the like, which might occur owing to the failure of pressure in
the hydraulic main.
According to my invention I arrange in combination with the inlet and exhaust
valves a third valve which, so long as the pressure is maintained in the hydraulie
main, remains open, but which, when little or no pressure exists in the main,
closes to prevent the water on the pressure side of the ram cylinder from flowing
back into the main under the pressure upon the ram.
To enable my invention to be fully understood I will describe the same by
reference to the accompanying drawing which shows in sectional elevation a
valve box with inlet and exhaust valves arranged in the manner described in
the specification before referred to with which is combined a non-return valve in
accordance with the present invention.
« is the casing of the valve and b, c are the inlet and exhaust valves respec-
tively which are operated by the double cam, the said valve serving, when
opened, to admit pressure water from the inlet chamber e to the ram cylinder
through the passage f, and the valve when opened to allow the water from the
ram cylinder to escape to the exhaust chamber g.
h i are passages formed through the valves b, c respectively for admitting the
pressure water above the said valves in order to close the same when released
by the cam d and keep them closed, the light springs being provided to over-
come any friction between the valves and the leathers j, j through which they
pass.
is the non-return valve arranged according to my invention, the said valve,
as shewn, working in a chamber formed in an extension of the casing and
being adapted to close the passage m through which the pressure water flows to
the inlet valve b. This valve has its stem extending through a packing
ring o which prevents the leakage of water around the stem and is at its upper
end acted upon by a spring which normally tends to press the said valve against
its seat.
P
In practice the upper end of the valve stem is located in a chamber which is
open to the atmosphere, or into which water pressure is not admitted, so that,
so long as the pressure in the supply main is maintained, the valve k will be
held open against the pressure of the spring ; should, however, the pressure
in the main fall, the water would act to close the valve against its seat and so
prevent the pressure water in the ram cylinder from escaping back into the supply
pipe, the said valve being provided with a flange against which the water in its
backward flow will act.
By the use of my invention a load which has been raised by the pressure water
will be held up in case the pressure in the main is suddenly lost and can then
be gradually lowered in the ordinary manner so that no accident can arise.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. The combination with a hydraulic working valve of a non-return valve which,
in case of the pressure in the hydraulic main being reduced below a certain point,
will prevent the backward flow of the water from the ram cylinder in connection
with the said valve, substantially as described.
2. The combination with a hydraulic working valve containing inlet and
exhaust valves, of a non-return valve which, in case of the pressure in the hydraulie
main being reduced below a certain point, will prevent the backward flow of the
water from the ram cylinder in connection with the working valve, the exhaust
valve being provided with a passage which enables it to be opened and controlled
when the main water supply has failed, substantially as described.

page_text: 3. The manufacture and use of hydraulic working valves substantially as hero-
inbefore described and illustrated in the accompanying drawing,
11
1011 1
e
1000
G. F. REDFERN & Co.,
4, South Street, Finsbury, London,
Agents for the Applicant.