Improvements in or relating to Pressure Controlling Apparatus.
Year: 1896

page_text: Date of Application, 4th June, 1896-Accepted, 11th July, 1896
COMPLETE SPECIFICATION.
Improvements in or relating to Pressure Controlling Apparatus.
We, ALOIS HORA of Prague-Karolinenthal Patackystrasse 331, and VACLAV
WENZEL, Engineer, of Prague-Zizkow, Prokopplatz, both in the Empire of Austria,
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:-
This invention relates to a device by means of which the pressure of a liquid or
gas contained in a vessel is kept constant. This regulating device is applicable only
where the liquid or gas whose pressure is to be maintained constant is in a state of
circulation or continuous flow. A small part of the running liquid (or gas) passes
into a cylinder through ports or openings, the effective size of which may be
regulated by a slide-valve, this admission of the liquid (or gas) taking place simul-
taneously on both sides of a piston in the cylinder. The piston rod is hollow and
serves as an outlet for the liquid (or gas) admitted into the cylinder, the interior of
the hollow piston rod being in communication with the interior of the cylinder by
means of slots.
The regulation is effected by alteration of the effective size of the admission
openings, whereby the quantity of liquid (or gas) entering the cylinder and con-
sequently also the pressure on the piston is altered, if of course the outlets in the
piston rod remain unchanged. The difference in pressure on the two sides of the
piston causes the latter to move until an equal proportion between the inlet and
outlet openings-the equilibrium-is attained.
The movement of the piston causes according to circumstances, a greater or
smaller opening of the valve which regulates the through-flow of liquid (or gas) by
which pressure in the vessel is generated. The slide valve is therefore caused to
move by the alteration of pressure in the vessel, which movement of the slide-valve
causes the piston and therefore the regulating valve to move.
In the accompanying drawings
Fig. 1 is a vertical and a horizontal section of the regulating device.
Fig. 2 is a section of a practical example of the regulating device and
Figs. 3 and 4 show by way of example views of two different practical applications
of the device.
The slide valve B which in the example illustrated is of tubular form is operated
from the outside by the alterations in pressure, has openings or ports 1 and 2,
through which the running liquid (or gas) is admitted simultaneously to both sides
of the piston A which is movable in the cylinder A¹, from which latter the liquid
(or gas) escapes through slots or openings I and II and through the hollow piston
rod C. The piston A is fast on the piston rod C.
When the valve B is moved so that one of the openings for instance 1-becomes
in effect larger and the other one smaller, inore liquid (or gas) is admitted through
the first opening than through the second, and as the outlet openings I and II still
remain of the same size, the consequence will be that the pressure above the piston A
will be greater than that below it, whereby the piston will be caused to move
downwards. But this movement produces an increase in the effective area of the
outlet opening I and a corresponding decrease in the effective area of the outlet
opening 11, so that the piston will move only so far as to bring the openings 1 and 1
on the one hand and 2 and II on the other hand into equal relation.
As may be seen from the practical constructive application in Fig. 2, the piston

page_text: rod C is connected to a valve D which is opened to a greater extent by the above
described downward movement of the piston A, so that the liquid (or gas) passing
through said valve in the direction of the arrows is allowed a greater area for its
passage.
From the inlet p branches off a passage pl through which and another passage p
the liquid (or gas) from p is admitted into the slide valve B, from which it passes
in the manner above described into the hollow piston rod C and finally passes
through a passage U, after which it may be utilised in any desired manner.
In order that the valve B may be moved by the alteration of the pressure there is
arranged in a chamber K a diaphragm M, which divides the chamber K into two
compartments, one of which is connected to the vessel, in which the pressure is
to be kept constant, so that the pressure in this compartment may be the same
as the vessel. The branch J leading from this compartment is connected to the
vessel.
In the other compartment of the chamber K, from which compartment leads
the branch P, a constant pressure is maintained, as for instance, by means of a water
or a liquid column 0 (Figs. 3 and 4). The diaphragm M is secured to the slide
valve B and it is clear that alterations of pressure in the chamber K above the
diaphragm M (if the pressure under it remains constant) will effect a movement of
the valve B.
Fig. 3 shows the application of the regulating device to the manufacture of
spirit.
In a vessel N a liquid, the level of which is at n-n has to be evaporated in such
manner, that the pressure above the liquid will not vary more than a certain small
amount or remains nearly constant.
The necessary heat is supplied by say steam pipes L and 1. The pressure in the
vessel N depends therefore on the quantity of heat supplied; the steam is therefore
led first through the valve D and also through the slide valve B and cylinder A.
The branch J is connected with the vessel N above the level of the liquid
therein and to the branch P is joined a pipe O, in which a constant pressure is
maintained by means of say a column of water, the level of which is at mm;
the condensed water from the pipes L is drained off through the pipes s r. The
steam which is allowed to pass through the pipe L is controlled by the valve D
and that passing through the pipe l is controlled by the ports 1, I, 2 II.
A second practical application is shown in Fig. 4 where the pressure of running
water, steam or gas in a vessel W has to be maintained constant, whether the pressure
in front of the valve D be constant or not.
The manner of connecting the vessel W and the mode of working will be
sufficiently well understood from the drawing and from the preceding description to
render further explanation unnecessary.
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. A device for maintaining the pressure of liquid or gas constant in which a part
of the liquid or gas is allowed to pass simultaneously through two ports or openings
1 and 2 of a slide valve such as B to the two sides of a piston A and allowed to
escape through openings such as I and II of the bollow piston rod the proportion
between the free or effective areas of the ports or openings 1 and I and 2 and II
always remaining the same so that if in consequence of variation in the pressure
to be controlled the free or effective area of the openings 1 and 2 of the slide valve
is altered the piston A is moved to such a position that an equal relation between the
openings 1 and I and 2 and II is re-established the movement of the piston A serving
to adjust the valve controlling the through-flow of the liquid or gas substantially as
described.
2. In apparatus such as set forth in Claim 1 the employment for operating the
tubular sliding valve of a diaphragmn such as M arranged in a chamber this operation

page_text: causing the effective areas of the ports or openings 1 and 2 in the slide valve to be
altered in such way as to cause the piston to move in a cylinder A' and at the same
time to open more or less the valve secured to the piston rod substantially as
described.
3. The combination and arrangement of parts constituting the complete regulating
device substantially as described and illustrated in Figs. 1, 2 3 or 4 of the accom-
panying drawings.
BOULT & WADE,
Agents for the Applicants.