stop valves and the like
Year: 1896

page_text: Date of Application, 8th Apr.. 1894
Complete Specification Left. 8.h Jan., 1897-Accepted, 27th Mar., 1897
to stop valves and the like.
A communication from MARIUS GROIGNARD, Engineer, of 123 Avenue d'Arenc,
Marseille, in the Republic of France.
I, ALFRED JULIUS BOULT, of 111 Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention to be as
follows:-
The present invention relates to a valve in which the valve proper is connecte l
by its spindle with two pistons of different diameters in order to ensure in a stop-
valve for steam, for example, quick closing of the valve in case of the breakage of
the steam pipe and at the same time to maintain the valve open simply by the
steam pressure, after it has been once opened by turning the hand wheel.
The valve proper may be a disc valve intended to be pressed against its seat.
The device comprises a movable piston (hereinafter termed the "upper piston")
in a cylinder open at the top, which cylinder is made in an extension of the valve
seat; the outer surface of this piston is exposed to the steam pressure existing
above (ie. the "efflux side" of the valve); this piston is connected with the valve
by a spindle, as also is a follower piston, which latter is a movable piston in a
cylinder open near the bottom and made in the part of the valve shell into which
the arriving steam is received; its under surface is exposed to the pressure of the
incoming steam, in the example now being considered.
The follower piston always must be of a smaller diameter than that of the upper
piston.
There will be a resistance to overcome when opening the valve by its hand
wheel, by reason of the valve dise being of larger area than the follower piston.
But as soon as this resistance is overcome, that is to say as soon as the valve is
slightly detached from its seat, a counter pressure will be produced in consequence
of the difference of the diameters of the upper and follower pistons; this counter-
pressure will balance and soon become greater than the original resistance so that
when the opening is completed, the pressures before and behind the valve disc
being balanced, the valve will remain in the position, into which it is moved by the
aid of the screw-threaded valve-spindle. Then this spindle is brought into the
middle of its travel plus say one or two millimetres. In this position the valve is
subject to a pressure in the direction contrary to that of the original resistance,
and the valve will remain open without help of anything else.
Should now the steam ontlet pipe break, the pressure over the valve will
become equal to one atmosphere from which it follows that the valve would be
subject to a new pressure in the direction opposite to that which was exerted on it
just before the breakage, so that the valve will return to its seat automatically and
instantaneously.
As soon as the stoppage is produced the same conditions exist as were originally
explained.
The working of the valve is as follows;-
Supposing the valve to be closed the opening is effected by turning the hand
wheel. The inner head of the spindle moves at first without effect till it touches

page_text: part of the upper piston. Then this latter begins to move aud causes movement
of the valve, which opens, offering a resistance as aforesaid. The opening is
continued till it is complete. As soon as the complete opening has taken place
and as the valve is kept in that position solely by the steam pressure, the inner
head is again moved upwards till it passes the middle between the two end
positions by say two millimetres. This is the position of working under normal
circumstances.
In case of breakage, as has been mentioned before, the balance of the valve
being disturbed, it is thrown against its seat and stops the steam passage.
The ordinary shutting, on the contrary is effected by simply turning the hand
wheel in the opposite direction, till the inner head is brought back to the original
position.
Such stop valves being able to work in any position can be used in any manner
desired, and for gas or compressed air or other fluids besides steam. They can
be equally well applied to water pipes or pipes for other liquids under pressure.
As an example of their application may be mentioned the water gauges of steam
boilers on which it is fitted in order to prevent escape of steam in case of the
breakage of the gauge-glass.
Dated this 8th day of Anvil 1806
BOULT & WADE,
Agents for the Applicant.
A communication from MARIUS GROIGNARD, Engineer, of 123 Avenue d'Arenc,
Marseille, in the Republic of France.
I, ALFRED JULIUS BOULT, of 111 Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, 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 present invention relates to a valve in which the valve proper is connected
by its spindle with two pistons of different diameters in order to ensure in a stop-
valve for steam for example, quick closing of the valve in case of the breakage of
the steam pipe and at the same time to maintain the valve open simply by the
steam pressure, after it has been once opened by turning the hand wheel.
The stop valve is represented in
Fig. 1 in section the valve being shown in its entirety and in its "shut "
position.
Fig. 2 represents it open under normal circumstances, and
Fig. 3 shows it shut after breakage of the steam pipe.
A is the steam inlet and B the steam outlet.
C is the valve proper pressed against its seat.
P is a movable piston hereinafter termed the upper piston in a cylinder K open
at the top, which cylinder is made in an extension of the valve seat; the outer
surface of this piston is exposed to the steam pressure existing above (i.e. on the
"efflux side" J' of the valve); this piston is connected with the valve C by a
spindle Q, as also is the follower-piston p which latter is a movable piston in a
cylinder kopen near the bottom and made in the part of the valve shell H into
which the arriving steam is received; its under surface being exposed to the
pressure of the incoming steam.

page_text: The arrows Fig. 1 indicate the direction of steam Figs. 2 and 3 show the
different positions of the valve.
The follower piston p is in the present case and always must be of a smaller
diameter than that of the upper piston P. If F be the area of the piston P and
f the area of the piston p, n the steam pressure in atmospheres in front of the valve
(that is to say in the admission pipe) and N the pressure in the outlet pipe, that
is to say above the valve, D the area of the passage of the seat, the total
pressure with which the valve will be pressed against the seat will be, in the case
of Fig. 1:
from which it follows that the valve would be subject to a new pressure in the
direction opposite to that which was exerted on it just before the breakage, so that
the valve will return to its seat automatically and instantaneously, if the product fn
is greater than F.
Fig. 3 represents stoppage immediately after the breakage.
As soon as the stoppage is produced the same conditions exist as in the case of
Fig. 1.
The working of the valve is as follows:-
Supposing the valve is to be closed (Fig. 1) the opening is effected by turning
the hand wheel F. The inner head D of the spindle moves at first without effect
till it touches the lower part of the upper piston P. Then this latter begins to
move and causes movement of the valve C, which opens offering a resistance as
aforesaid. The opening is continued until it is complete. As soon as the complete
opening has taken place and as the valve is kept in that position solely by the
steam pressure, the inner head D is again moved upwards until it passes the middle
of the piston between its two end positions, by say millimeters as shown in Fig. 2.
This is the position of working under normal conditions.
In case of breakage of the steam pipe as has been mentioned before, the balance
of the valve being disturbed it is thrown against its seat and closes the steam
passage and the parts come into the position shown in Fig. 3.
The ordinary closing of the valve on the contrary is effected by simply turning
the hand wheel in the opposite direction till the inner head D is brought back to
its original position represented in Fig. 1.
Such stop valves being able to work in any position can be used in any manner

page_text: desired, and for gas or compressed air or other fluids, besides steam. They can
be equally well applied to water pipes or pipes for other liquids under pressure.
As an example of their application may be mentioned the water gauges of steam
boilers on which they may be fitted in order to prevent escape of steam in case of
the breakage of gauge-glasses.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent, and in what manner
the same is to be performed I declare that what I claim is :-
1. A stop-valve connected by its spindle with two pistons of different diameters
or area, one acted upon by the incoming fluid and the other by the outgoing fluid,
whereby when opened, the valve is maintained in position by the pressure of the
steam or other fluid and should the pipe break the valve will be returned to its
seat, substantially as described.
2. The construction and arrangements of parts forming a complete stop-valve
substantially as described and illustrated in the accompanying drawing.
3. An automatic stop-valve provided with differential pistons substantially as
and for the purpose described.
Dated this 6th day of January 1897.
BOULT & WADE,
Agents for the Applicant.