Improvements in or Appertaining to Apparatus for Reducing an Effluent Liquid to any Required Pressure below that of the Inlet Pressure and for Maintaining it at that Pressure.
Year: 1888

page_text: Date of Application, 14th Dec., 1889
Specification Accepted, 22nd Jan., 1889
Improvements in or Appertaining to Apparatus for Reducing an
Effluent Liquid to any Required Pressure below that of the Inlet
Pressure and for Maintaining it at that Pressure.
We, CHARLES LLOYD BRAITHWAITE Jun. and ISAAC BRAITHWAITE, both of Kendal,
in the County of Westmoreland, Sanitary Engineers, 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 :-
The object of this invention is to construct an apparatus by means of which
the pressure of a liquid passing through it may be reduced to any desired pressure.
To accomplish this object we cause the liquid, upon entering the apparatus at any
pressure above that ultimately required, to impinge against a piston or other suitable
device, which is provided with a hole or its equivalent either through it or past it,
whereby the inflowing liquid is permitted to pass to the back of the said piston
or equivalent device. The piston is made of such a weight, or is fitted at its back
with a spring of such a strength, that, when the pressure of the liquid on its opposite
sides is in equilibrium, it is moved in such a manner as to close the discharge or inlet
pipe or both and prevent the passage of the liquid through the apparatus. When,
however, a valve controlling the passage of liquid from the back of the piston, is
opened sufficiently, it relieves the pressure behind the piston, and the pressure of the
liquid at the front thereof being now no longer balanced, the said liquid forces back
the piston and escapes at the outlet of the apparatus. The said valve is controlled
by a piston or diaphragm, which is acted upon by the effluent liquid in such a manner
that whenever the pressure at the outlet exceeds the pressure required, the valve
is closed and effects a partial or entire closing of the main piston aforesaid.
The invention may be carried into effect as follows :-reference being had to the
accompanying drawings, in which,
Figure 1 is a central vertical section of the apparatus and
Figure 2 a transverse section on line xx, Figure 1.
In these, A is the inlet and B the outlet. C is a piston valve working in a
cylinder or valve chamber D, and adapted, when closed, to rest upon the end C of the
inlet pipe, or upon other suitable seating, so as to close the passage from the inlet- A

page_text: into the outlet B. The piston valve is provided with leathers C or other suitable
piston packing, and preferably with a ring of india-rubber, lead, or other suitable
material, which forms a yielding surface for the end of the inlet pipe to bear
against. The piston valve C is also perforated with one or more holes C+ opening
from the inlet to the chamber D at the back of the valve. The said perforation or
perforations are preferably formed in a downward extension C of the piston valve. so
that the lower end of the perforation may always be in the full pressure of the inflowing
liquid, however far the piston valve may he raised.
The valve chamber or cylinder 1 communicates by passages E E¹ with a chamber F
or its equivalent, and this latter communicates by one or more ports Fl or their
equivalent, with a controlling valve chamber G, which is connected with the outlet B
by a discharge pipe H.
The said passages, chambers, ports, and pipe form one continuous discharge passage
from the chamber D to the outlet. B, and the narrowest portion, that is the discharge
area, of the said passage must be greater than the sectional area of tho per-
foration or its equivalent, for a reason hereinafter set forth.
It
The ports For their equivalent are adapted to be closed to a greater or less extent
by controlling valve K. L L of any suitable description, working within the controlling
chamber G. We have found that the form of controlling valve shown in the drawing
answers the purpose very well, in cases where, when the apparatus is in use as a
pressure reducer, there is always a small flow of water required through it.
consists of a piston K in the lower end of the chamber G, and adapted to successively
close the ports F¹ with its upper edge, as it is raised within the chamber. The
piston K is so perforated, as at k, that the liquid in the chamber may pass to its under
side, and so keep it in equilibrium. Connected by a stem L with the piston K, is
another piston L which works in the cylinder G freely, but sufficiently tightly to
prevent the passage of liquid. This piston is pressed downwards in the cylinder G
by a spring or springs M or by weights, or by a column of liquid, or in any other
suitable way, so that it will not be raised above its normal position by the pressure
of the liquid under it until that pressure reaches what is required in the outflowing
liquid. The pressure exerted by the spring upon the piston L' may be regulated as
desired by a set screw M¹ or other equivalent device. The pipe H must have its
entrance to the chamber G above the highest of the ports F¹, and below the lowest
point to which the underside of the piston L' can fall.
The working of the apparatus is as follows:-
Suppose, in the first instance, that the apparatus is in action, and that very little
more liquid is drawn from the outlet B than can leak past the valve K, but not so
much as can pass through the hole C, the prossure at the inlet exceeding that
required at the outlet. The pressure in the outlet would tend to rise to that in the
inlet, but as soon as it exceeds by ever so little, the pressure for which the
piston Lis weighted, the said piston will rise above its normal position, and lift the
valve K until the ports F¹ are all or nearly all closed, so that only as much liquid
passes the valve K as is necessary to maintain the pressure in the outlet at that
required. If rather more is drawn off at B, the pressure will tend to be reduced, and
the piston Land valve K will fall below their normal position and open more of
the ports F. If, however, the quantity drawn of approaches or exceeds what can
pass through the hole C, the pressure in the chamber D will be lowered until
the pressure exerted by the liquid in chamber D on the piston C, together with
the weight of that piston (and the pressure off the spring behind it, if one he used)
are less than the pressure exerted by the liquid on the under surface of the piston C.
The piston will then rise and open the passage between the inlet and outlet pipes,
until so much liquid passes that the pressure in the outlet pipe rises and again lifts
the piston L and valve K, so as to close some of the ports F¹, and cause the
pressure in chamber D to increase until it, together with the weight and spring
(if any) of the piston C, exactly balance the pressure below that piston, when
the lair will remain stationary. Should the amount drawn off be decreased, the
pressure in the outlet will tend to increase, the valve K will tend to close the ports F³,

page_text: and the pressure in chamber D will thus be slightly increased and will force the
piston downwards until an equilibrium is again attained, at the standard pressure,
between the amount of liquid allowed to pass from the inlet to the outlet, and the
amount of liquid being drawn off.
Thus the pressure in the outlet B can never rise above the required amount, whether
much or little liquid is drawn off.
If it be desired to adapt the apparatus to be used also as a stop valve, a small
stop tap or valve J of any convenient kind, may be introduced in the passage leading
from the chamber D to the ports F'. When this valve is closed the liquid in the
chambor D acquires the pressure of the inflowing liquid, and the piston valve C
is permanently closed.
It will be obvious that the apparatus could be modified considerably without
departing from the principle of the invention. For example, a diaphragm may be
substituted for the piston L, and the said diaphragm or piston may be connected
with the controlling valve L, either directly, as shown in the drawing, or indirectly
by a lever or other suitable device. Also the controlling valve K may be of any
suitable form, and not necessarily a piston, the ports and chamber G being, of
course, inodified accordingly if needed. Moreover, a distending diaphragin valve
might be substituted though not so advantageously, (at least for a large apparatus),
for the main piston valve C, and the said diaphragm valve could be controlled by
a piston and valve controlling device such as K LL. Further, in cases where it
is desirable to work with a liquid pressure behind the piston L' or corresponding
diaphragmn, this end may be secured by providing a small passage or passages for
the liquid from the outlet side of the apparatus, into the space behind the said
piston or diaphragm, and by connecting this space with an escape valve weighted
to the required pressure. The passage or passages mentioned may conveniently be
through or alongside of the piston or diaphragm, and must, in all cases, be of
smaller area than the escape valve. Or, instead of making a special passage or
passages, the piston L' may be made to fit loosely in the chamber G.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what
we claim is :-
1. An apparatus for maintaining a constant reduced pressure in an effluent liquid,
consisting of an inlet A, an outlet B, communicating with the exit orifice of the
said inlet, a piston valve C adapted to control the said exit orifice, a hole Cor
its equivalent connecting the front and back of the said piston valve, a discharge
passage leading from the back of said piston valve to the outlet B, and having a
discharge area greater than the area of the perforation C or its equivalent, and a
controlling valve adapted to automatically control the discharge area of the said
passage, whereby any variations in the pressure of the effluent liquid affect the
pressure behind the said valve C in such a manner as to produce a partial or
entire opening or closing of the same, and restore the pressure of the effluent
liquid to its normal amount, substantially as described.
2. In combination with an apparatus such as set forth in Claim 1, a stop valve J
adapted to close the said discharge passage, whereby the main piston valve C may
be permanently closed and the effluent liquid shut off entirely, substantially as set
forth.
3. In an apparatus for maintaining a constant pressure in an effluent liquid, the
combination of a piston valve such as C, having its back in communication with the
inflowing and the effluent liquid, and of a controlling valve adapted to be acted upon
by the effluent liquid, whenever the pressure of the latter rises above the normal
pressure, in such a manner as to increase the pressure behind the said piston valve,
substantially as and for the purpose specified.
4. In combination with a discharge passage leading from the back of the piston
to the outlet B, the ports F' F' and the controlling chamber G forming part of said
passage, the automatic piston valve K L L' working within the chamber G and

page_text: adapted to close or partially close the ports F1, whenever the pressure in said passage
rises above a certain point, and an adjustable spring, weight or its equivalent, tending
to move the said valve downwards in opposition to said pressure, substantially as and
for the purpose described.
5. In an apparatus such as herein described, the combination of a main diaphragm
valve, mounted over the exit orifice of the inlet A, and having both its back and front
sides in communication with the inflowing liquid, of a discharge passage, connecting
the back of said diaphragm valve with the effluent liquid, and of a loaded piston valve
such as K L L, controlling the discharge area of said passage, substantially as and
for the purposes set forth.
6. The combination with a controlling valve or diaphragm such as herein described,
of means for adjusting the load on said valve, substantially as and for the purpose set
forth.
7. The apparatus for regulating and maintaining the pressure of an effluent liquid,
constructed as a whole, substantially as herein described and shown.
Dated this 12th day of Donnmhan 1000
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Patent Agents for the Applicants.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Patent Agents for the Applicants.