An Improved Method of Working Hydraulic Presses, and Apparatus for use in connection therewith.
Year: 1897

page_text: An Improved Method of Working Hydraulic Presses, and Apparatus
for use in connection therewith.
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 an improved method of working hydraulic presses and
apparatus for use in connection therewith.
It is well known that in working a hydraulic press the first and major portion
of the movement of the ram can be effected by a much lower pressure than is
required during the last part of the movement of the ram.
Hitherto, however, it has been considered necessary to operate the ram through
the whole of its course by water which is capable of producing the final pressure
required. When working a press with water at very high pressure it obviously
would be of advantage to consume as small a quantity of such high pressure water
as possible and the object of my invention is to provide means whereby a press
may be operated with a minimum expenditure of water.
According to my invention I provide for moving the ram during the greater
part of its stroke by means of water at a relatively low pressure and for applying
the high pressure water during only the last part of the. stroke.
In carrying out my invention I make use of what I may term a secondary
accumulator which comprises a duplex ram (that is to say, a ram having two parts
of different diameters) and two cylinders in which the two parts of the ram work,
the larger cylinder being connected with the working cylinder of the press and
the smaller cylinder in communication with the high pressure water supply.
The capacity of the large accumulator cylinder is equal to or greater than the
capacity of the ram cylinder of the press so that all the water in the press cylinder
may enter the large cylinder of the secondary accumulator.
In practice the areas of the two ends of the duplex ram are so proportioned that
the high pressure water in acting upon the small end will produce a pressure upon
the water in the large secondary accumulator cylinder sufficient for moving the
press ram during the major part of its stroke.
When the press ram has been moved sufficiently by the low pressure water a cock
is opened to admit the high pressure water directly into the cylinder of the press
ram to complete the stroke of the said ram.
With this arrangement it will be understood that the only water which is con-
sumed is the small quantity used to move the duplex ram plus the further quantity
which is introduced to complete the stroke of the press ram.
The low pressure
water which is used for operating the ram during the first part of its movement is
used over and over again.

page_text: An Improved Method of Working Hydraulic Presses, and Apparatus
for use in connection therewith.
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 ascer-
tained in and by the following statement:
-
My invention relates to an improved method of working hydraulic presses and
apparatus for use in connection therewith.
It is well known that in working a hydraulic press the first and major portion
of the movement of the ram can be effected by a much lower pressure than is
required during the last part of the movement of the ram.
Hitherto, however, it has been considered necessary to operate the ram through
the whole of its course by water which is capable of producing the final pressure
required. When working a press with water at very high pressure it obviously
would be of advantage to consume as small a quantity of such high pressure water
as possible and the object of my invention is to provide means whereby a press
may be operated with a minimum expenditure of water.
According to my invention I provide for moving the ram during the greater
part of its stroke by means of water at a relatively low pressure and for applying
the high pressure water during only the last part of the stroke.
In carrying out my invention I make use of a duplex ram (that is to say, a ram
having two parts of different diameters) and two cylinders in which the two parts of
the ram work, the larger cylinder hereinafter referred to as the reservoir cylinder
being connected with the working cylinder of the press and of sufficient size to
receive the water exhausted from the working cylinder and the smaller cylinder
hereinafter referred to as the compression cylinder being in communication with the
high pressure water supply.
In practice the areas of the two ends of the duplex ram are so proportioned that
the high pressure water in acting upon the small end will produce a pressure upon
the water in the reservoir cylinder sufficient for moving the press ram during the
major part of its stroke.
When the press ram has been moved sufficiently by the low pressure water a
valve is opened to admit the high pressure water directly into the working cylinder
to complete the stroke of the said ram.
To enable my invention to be fully understood I will describe the same by
reference to the accompanying drawing which represents in diagrammatic form an
arrangement of apparatus according to my invention.
a is the press ram to be operated, and 6 the working cylinder for the same. c is
the valve for admitting high pressure water from the supply pipe d through the
pipe to the working cylinder b, and f is the valve for allowing the water to
exhaust from the said cylinder b; the said valve, however, also serves for the
admission of low pressure water as hereinafter described. h is my duplex ram the 4
large end i of which works in the reservoir cylinder j and the small end k works in
the compression cylinder l.
The reservoir cylinder j is connected with the casing of the valve f by the pipe m,
and the compression cylinder is connected by the pipe n with the casings of two
valves o, p, the former of which serves for admitting high pressure water into the
compression cylinder 7 and the latter of which serves for the exhaust of the water
from the said compression cylinder 7.
The valves e, f, o, p, may be of any desirable construction; in the drawing, how-

page_text: ever, I have represented two duplex valves each of the kind described in the Specifi-
cation of Patent No. 14563 of 1891 granted to the late F. W. Scott, Jnr., wherein
the valves are operated by a cam through the medium of a lever.
The operation of the apparatus herein before described is as follows,-Assume the
parts to be in the position shewn in the drawing, that is to say, the ram a to be in
its lowest position and the reservoir cylinder j full of water. If now the valves o
and fare opened high pressure water will enter the compression cylinder / and lift the
ram h displacing the water from the reservoir cylinder j and causing it to flow
through the pipe m, the valve f and the pipe e to the working cylinder 6 lifting the
ram a. When the ram a has been moved as far as possible under this low pressure,
the valves o and f are closed and the valve c is opened so that high pressure water
flows from the pipe d through the pipe e into the working cylinder 6 to complete
the stroke of the ram. When the stroke is completed, the valves f and p are
opened so that the water from the working cylinder flows through the pipe e and
the pipe m to the reservoir cylinder j and the water from the compression cylinder
flows through the pipe n to the exhaust valve p.
From the foregoing description it will be understood that the only water which is
consumed is the small quantity used to move the ram h plus the further quantity
which is introduced to complete the stroke of the press ram a.
The low pressure
water which is used for operating the ram during the first and major part of its
movement is practically used over and over again.
To allow of the escape from the reservoir cylinder j of the corresponding quantity of
water to that of high pressure water introduced into the working cylinder b, I provide a
valve q which is weighted so that it will not open under the normal pressure in the
said reservoir cylinder j, the lever of this valve, however, has connected to it one end
of a cord or chain r, the other end of which extends into proximity to the person
operating the apparatus so that he can, when desired, open the valve q to allow
of the requisite quantity of water being discharged through the said valve to permit
of the ram a moving to its lowest position.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. The method of working a hydraulic press or the like by high pressure water
consisting in utilizing the high pressure water, during the major portion of the
movement of the ram, for compressing a body of water to an extent sufficient to
operate the ram and forcing this water into the working cylinder, and then intro-
ducing high pressure water into the said working cylinder during the latter part
of the movement of the ram, substantially as, and for the purpose, described.
2. The combination with a hydraulic press of a reservoir cylinder in communica-
tion with the working cylinder of the press a piston or ram working in the said
cylinder and operated to compress the water in the reservoir cylinder by a ram of
smaller area working in an independent cylinder in communication with a high
pressure water supply the said working cylinder of the press ram being also in com-
munication with the high pressure water supply and suitable valves for controlling
the admission and escape of water into and from the said cylinders, substantially as,
and for the purpose, described.
3. The arrangement of apparatus, substantially as herein before described by
reference to the accompanying drawing for the purpose specified.
Dated the 7th I
T
1000
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.