Improvements in and connected with Equilibrium Valves.
Year: 1889

page_text: Date of Application, 4th June, 1889
Complete Specification Left, 4th Mar., 1890-Accepted, 5th Apr., 1890
PROVISIONAL SPECIFICATION.
Improvements in and connected with Equilibrium Valves.
We ISAAC SHIMWELL MCDOUGALL and JAMES THOMAS MCDOUGALL both of
10 Mark Lane in the City of London Manufacturing Chemists and WILLIAM
HENRY FOWLER of 21 Church Road Middleton Junction near Manchester in the
County of Lancaster Civil Engineer do hereby declare the nature of our said
Invention to be as follows:-
Ordinary equilibrium valves are generally constructed with two valves and are
connected with a spindle they being cast together and turned and fitted to a double
seating so that the bearing surface of each valve is annular and the inner diameter of
the annulus is the true diameter of the valve. In consequence of one valve having
to be passed through the opening in the seating of the other valve the surfaces of the
two valves on which pressure is exerted are not equal and the valves are therefore
not in perfect equilibrium and consequently some considerable pressure is required to
open or close them. Further the bearing surfaces of the valves on their seatings are
not equal to each other in area and therefore do not wear evenly causing leakage.
Further the flat bearing surfaces form a resting place for the accumulation of scale or
dirt which also causes the valve to leak and necessitates regrinding.
To meet these objections double piston valves have been adopted but these are
objectionable on account of their requiring considerable lift before opening and
because they are apt by becoming coated with grease or scale to stick fast or else
gives rise to objectionable friction.
This invention has for its object to obviate these objections by constructing or
arranging the device so that each valve when resting on its seating can be of exactly
the same area and therefore be subjected to equal pressures and consequently be in
true equilibrium.
According to this Invention the two valves which combined together form the
equilibrium valve are connected to each other by a central spindle having a screw
'thread formed upon it either at one end or at both ends for screwing into one or both
valves so that the distance apart between the two valves can when necessary be
regulated as required.
The two valves being adjusted to the correct distance apart they can be locked fast
to the spindle either by lock nuts running on the spindle itself and abutting against
'the valves or if preferred by solid plugs screwed into the hole in the valve and
abutting against the end of the spindle.
The bearing surfaces of the valve may be either flat curved or spherical as
desired.
For convenience of fitting and adjustment the seatings of the valves may be made
separable from the chest or body of the pipe or vessel in which they are contained
means of access being provided so that one of the valves may be placed on its seat-
without having to pass it through the opening in the seating of the other valve.
Dated this 4th day of June 1889.
TANKSON ..

page_text: COMPLETE SPECIFICATION
Improvements in and connected with Equilibrium Valves.
We ISAAC SHIMWELL MCDOUGALL and JAMES THOMAS MCDOUGALL both of
10 Mark Lane in the City of London Manufacturing Chemists and WILLIAM
HENRY FOWLER of 21 Church Road Middleton Junction near Manchester in the
County of Lancaster Civil 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:—
Ordinary equilibrium valves are generally constructed with two valves which are
connected with a spindle they being cast together and turned and fitted to a double
seating so that the bearing surface of each valve is annular and the inner diameter
of the annulus is the true diameter of the valve. In consequence of one valve
having to be passed through the opening in the seating of the other valve the
surfaces of the two valves on which pressure is exerted are not equal and the valves
are therefore not in perfect equilibrium and consequently some considerable pressure
is required to open or close them. Further the bearing, surfaces of the valves on
their seatings are not equal to each other in area and therefore do not wear evenly
causing leakage. Further the flat bearing surfaces form a resting place for the
accumulation of scale or dirt which also causes the valve to leak and necessitates
regrinding.
To meet these objections double piston valves have been adopted but these are
objectionable on account of their requiring considerable lift before opening and
because they are apt by becoming coated with grease or scale to stick fast or else give
rise to objectionable friction.
This invention has for its object to obviate these objections by constructing, or
arranging the device so that each valve when resting on its seating can be of exactly
the same area and therefore be subjected to equal pressures and consequently be in
true equilibrium.
According to this invention the two valves which combined together form the
equilibrium valve are connected to each other by a central spindle having a screw
thread formed upon it either at one end or at both ends for securing one or both
valves and so that the distance apart between the two valves can if so desired and
when necessary be regulated as required. The two valves being adjusted to the
correct distance apart they can be locked fast to the spindle either by lock nuts
running on the spindle itself and abutting against the valves or if preferred by solid
plugs screwed into the hole in the valve and abutting against the end of the spindle.
The bearing surfaces of the valve may be either flat curved or spherical as desired.
The valves can both by this arrangement have equal areas presented to the pressure
and to the valve seats. For convenience of fitting and adjustment the seatings of the
valves may be made separable from the chest or body of the pipe or vessel in which
they are contained means of access being provided so that one of the valves may be
placed on its seat without having to pass it through the opening in the seating of the
other valve.
The accompanying drawing illustrates two equilibrium valves constructed or
arranged according to this Invention. In Figure 1 A is the valve casing and B B*
are the valves which are of equal size and are secured on the spindle by means of
nuts d which are screwed upon the spindle C so that the lower valve B³ can be
regulated exactly to a distance from the other, valve B to suit the valve seats and be
then secured in proper position. Figure 2 shews an arrangement wherein the
valve B2 is itself screwed on to the spindle C. The seatings e e³ for the valves are
made in the bushing e and the valves can be removed when required by unscrewing
the lower valve or the lower nuts from the spindle and so the spindle and upper valve
can be removed and also the lower valve as soon as the spindle is drawn away
from it.

page_text: It will be evident that the details of construction can be considerably varied
without departing from the nature of this Invention for instance in Figure 1 the
nuts above the lower valve can be replaced by a collar or flange fixed or formned on
the spindle.
Having now particularly described and ascertained the nature of this said Inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
First An equilibrium valve consisting of two valves of equal area or diameter and
seating themselves upon seatings of the same size and attached to the spindle so that
the valves can both be removed in the manner substantially as herein before described.
Second The equilibrium valve as illustrated in either Figure 1 or Figure 2 of the
accompanying drawings and described with reference thereto.
Dated this 4th day of March 1890
J. H. JOHNSON & Co.,
Agents.