Improvements in Working Valves for Hydraulic Machinery.
Year: 1893

page_text: Date of Application, 21st Dec., 1893-Accepted, 3rd Mar., 1894
COMPLETE SPECIFICATION.
Improvements in Working Valves for Hydraulic Machinery.
I, GEORGE MITCHELL, of 47, Victoria Street, Westminster, 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 valves and has for its object First: The
balancing of two valves known as the "inlet" and "exhaust" valves within one
box or valve casing. Second: The opening of same by means of one lever or screw
and its attachments.
And in order that my invention may be fully understood and readily carried into
effect I will.describe the same with accompanying drawings reference being had to
the letters and figures marked thereon.
Fig. 1. Sheet 1. is a full elevation of the hydraulic valve box mounted on a
detachable sole plate carrying the lever attachment shown in section,
Fig. 2. Sheet 1. shows the valve box in sectional plan.
Fig. 3. Sheet 2. is the valve box with lever attachment in full end elevation.
Figures 4, 5, & 6, are sections through the valve box respectively on the
lines A-B; C-D; E-F; on the sectional plan Figure 2. Sheet 1.
My invention consists firstly: in the arrangement of the inlet balanced valve "a,"
and the exhaust valve "," balanced within the valve box or casing "c," secondly,
in the valve spindle "d," and arrangement for connecting same with the valves "a,"
and "b," and the lever "e."
The inlet pressure valve “a,” is_constructed hollow, and on its back, or top side,
a cylinder having an external diameter slightly less than the diameter of the
pressure valve seat, and an internal diameter equal to the exhaust, is carried
through the leather or such form of packing ring "," secured in place by means of
the screwed gland "g." The external diameter of the cylinder "al"
; on the
valve "a," having a less sectional area than the valve seat or opening "h," obviously
the hydraulic or other pressure within the inlet passage and chamber "," will tend
to close the valve "a," and retain it in that position. The spring "j" is auxiliary
to the working of the valve; its object being to keep the valve in place while
there is no pressure in the inlet passage "," also to start the valve in the event
of there being an equilibrium of pressure on both sides of the valve " a.
"
"
The exhaust valve "," has for its seat, the inner end of the cylindrical inlet
valve “a,” and is balanced by means of the ram or cylinder "," which forms part
of the valve and is carried through the leather or such form of packing ring "k,"
secured in place by means of the screwed gland "." The ram or cylinder "61,"
on the valve "b," having a less sectional area than the valve seat or outlet ".
obviously the hydraulic or other pressure acting on the valve "b," will tend to
close it and retain it in that position. The spring "n," is auxiliary to the working
of the valve "b," and has for its object keeping the valve closed prior to hydraulic
or other pressure being admitted against it.
m,'
From the exhaust valve "b," the outlet passage is continued through the centre
of the valve "a," and through the holes "," in the cylinder "a'," escaping into
first annular groove "P," between the valve cylinder "a" and the gland "g," the
passage is further continued through the holes "q" in the gland" 9. "into the outer
annular groove "," in the valve box or casing "c," with which is connected the
exhaust outlet and pipe "." The spindle d," is carried through the small
packing gland "t," and connected by a screw socket "u," with adjusting nut, to
66
the links” in which are the roller 16 and & on" acted on by the cam lever ""

page_text: act as stops, when they are brought over and bear
"
on which the projections “
on the respective rollers.
The pin "y," is the fixed centre on which the cam lever "e," works and the
slots "" in the links "v," allow for the forward and backward movement of the
links when actuated by the lever on its fixed centre, when necessary the lever ",
may have a quadrant and ratchet attached so as to allow of its being fixed at any
required position of the stroke. The valve spindle "d," may equivalently be
actuated by means of a screw in the gland "g," or such other convenient manner.
Where more than one pair of valves are necessary they can be made quadruple
or any such multiple within one box or casing, having a common "inlet" and
"exhaust" and worked by the same or independent movements.
The nature of my invention having been fully set forth in conjunction with
accompanying drawings I will now describe one mauner of actuating the valves and
the effect produced on the relative parts in actual practice.
a
The valve box or casing as shown on the accompanying drawings has both inlet
and exhaust represented as closed. To admit pressure through the valve "a," from
its source of supply the lever is pulled over, transmitting the force applied by
means of the cam on its lower extremity to the roller "," and by the links "r,"
and the spindle "d," direct to the pressure valve " "the valve being drawn back
and opened by the collar "d" on the spindle and at the same time compressing
the spring "," pressure is admitted from the source "i" through the valve seat ","
to the chamber connected with "P." To exhaust the pressure thus admitted the
lever "e," is reversed and the retaining collar "d"," relieved from the valve "a,"
which automatically closes, and the point of the spindle now comes in contact with
the valve "b," and lifts it from its seat "m," at the same time compressing the
spring "n" and allowing the pressure to escape along the passage in the valve "a,'
through the holes "o & 9," to the exhaust pipe 3.' The lever being now
released returns to its original or normal position taking with it the spindle "d,"
and releasing the pressure on the valve "b," which automatically closes to the
position shown on the accompanying drawings.
66 "
"
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 balancing of two movable cylindrical valves, one being "pressure" and
the other "exhaust" on one valve seat within one valve box or casing.
2. Constructing the movable cylindrical exhaust valve so as to have its seat on
and work within the movable cylindrical pressure valve.
3. The arrangement of two movable cylindrical valves known and described as
the "pressure" and "exhaust" valves balanced within one valve box or casing
actuated by a single spindle in contact with one screw or lever by means of which
both valves cannot be " open at the same time.
"
4. The construction, combination and arrangement of parts constituting the
improved, balanced, double-acting hydraulic valve substantially as fully described
and set forth in the accompanying Specification and drawings.
Dated this 20th day of December 1803
GEO.
MITCHELL,
47, Victoria Street, Westminster, S.W.