An Improved Stop Valve for Boilers and the Steam Pipes connected therewith.
Year: 1891

page_text: Date of Application, 7th May, 1891!
Complete Specification Left, 5th Feb., 1892-Accepted, 5th Mar., 1892
PROVISIONAL SPECIFICATION.
An Improved Stop Valve for Boilers and the Steam Pipes connected
therewith.
I, JOHN MACLAREN MALLOCH, of Gillburn Terrace, Downfield, Dundee, in
the County of Forfar, N.B. Mechanical Engineer, do hereby declare the nature of
this invention to be as follows:-
This invention relates to stop valves for boilers and the steam pipes connected
therewith, its objects being to provide a means by which the exit of steam from
the boilers to the said pipe may be suddenly stopped should a steam pipe burst, or
should an accident occur in any part of the works. When a steam pipe bursts, or
when the speed of the engine exceeds a certain limit, the valve closes automatically,
but in other cases it can only be closed at the will of the operator.
In carrying out my invention according to one modification, I affix close to the
ordinary stop valve at the steam boiler or at the junction of the branches from two
or more boilers with the main steam pipe, my stop valve in such a position that all
the steam supplied through the steam pipes to the engine, or otherwise, for other
purposes, must pass through it; the valve being so designed, that when it is closed,
the pressure of the boiler steam will tend to keep it shut. On the top of said valve
is a cylinder in which a piston works, said piston being coupled to the valve by
means of a rod which passes through a stuffing box in the valve casing. The piston
is preferably of such an area, that a pressure equal to, or even somewhat less than
that of the boiler will lift the valve when it is closed; should it be found necessary.
The pressure of the steam in the steam pipe acts on the under side of the valve
piston by means of a small pipe-preferably filled with water-the other extremity
of the pipe terminating in the steam pipe at the end next the engine, or other
terminal point of the said steam pipe.
By arranging the stop valve and its appurtenances in the manner indicated; a
lowering of pressure due to the bursting of the steam pipe, engine cylinder or other
cause-except the lowering of pressure in the boiler or boilers-will allow the valve
to close, and thus shut off the steam. In addition to the small pipe communicating
I
between the stop valve and the other extremity of the steam pipe;
may either
carry the said small pipe past various suitable stations in the engine room, the
works, or in steamships to any part of the vessel, and then to the steam pipe; or I
may introduce a supplementary branch pipe which will pass the said stations, 50
that when it may be desirous to actuate the valve so as to shut off the steam at any
particular station; all that has to be done will be to open a cock and let the water,
or other fluid escape from the said small pipe.
In another modification I may design my valve to act as an ordinary stop valve,
as well as an emergency stop valve.
It will be obvious that my stop valve may be modified to suit steamers, in order
that the captain, when standing on the "bridge" may have power to stop the
engines without losing time by communicating to the engineer in the engine room,
should he deem it necessary.
Dated this 5th day of May 1891.
GEO. C. DOUGLAS & Co.,
Applicant's Agents.

page_text: COMPLETE SPECIFICATION.
An Improved Stop Valve for Boilers and the Steam Pipes connected
therewith.
I, JOHN MACLAREN MALLOCH, of Gillburn Terrace, Downfield, Dundee, in
the County of Forfar, N.B. Mechanical 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 :-
This invention relates to stop valves for boilers and the steam pipes connected
therewith, its objects being to provide a means by which the exit of steam from the
boilers to the said pipe may be suddenly stopped should a steam pipe burst, or
should an accident occur in any part of the works. When a steam pipe bursts, or
when the speed of the engine exceeds a certain limit, the valve closes automatically,
but in other cases it can only be closed at the will of the operator.
The accompanying sheets of explanatory drawings illustrate the method of
carrying out my invention according to one modification.
Figures 1. and 2. (Sheet No. 1.) represent respectively a sectional elevation of
my improved stop valve combined with exterior elevations of the boiler and engine
stop valves, and a plan of same, and Figure 3. (Sheet No. 2.) a plan showing the
pipe connections for a mill or factory.
In these drawings the same reference numerals are used to mark the same or like
parts wherever they are repeated.
In carrying out my invention, I affix close to the ordinary stop valve 4. at the
steam boiler, or at the junction of the branches from two or more boilers with the
main steam pipe, my stop valve 5. in such a position that the steam supplied through
the steam pipes to the engine, or otherwise, for other purposes, must pass through
it before it goes through to the engine stop valve 25, the valve 6. being so designed
that when it is closed, the pressure of the boiler steam will tend to keep it shut.
Preferably I make the said valve 6. of larger diameter than the boiler stop valve,
in order that its lift may be reduced to a minimum. On the top of, that is to say
above said valve 6. is a cylinder 7.-supported by and attached to the stop valve 5.
by means of four columns 24.-in which a piston 8. works, said piston being coupled
to the valve 6. by means of a rod 9. which passes through a stuffing box 10. in the
valve casing. The piston 8. is preferably of such an area, that a pressure equal
to, or even somewhat less than that of the boiler will lift the valve 6. when it is
closed. The pressure of the steam in the steam pipe 11. acts on the underside of
the valve piston 8. by means of a small pipe 12.-preferably filled with water
produced from steam by condensation-the other extremity of the pipe terminating
in the steam pipe at 13, the end next the engine, or other terminal point of the
said steam pipe.
By arranging the stop valve and its appurtenances in the manner indicated, a
lowering of pressure due to the bursting of the steam pipe, engine cylinder or other
cause except the lowering of pressure in the boiler or boilers-will allow the
valve 6. to close, and thus shut off the steam. I may carry the said small pipe 12.
past various suitable stations 14. (Figure 3.) in the engine room, the works; or in
steam ships to any part of the vessel, and then to the steam pipe 11. so that when
it may be desirous to actuate the valve 6. so as to shut off the steam at or from
any particular station, all that has to be done will be to open a two way cock 15.
and let the water or other fluid escape from the said small pipe 12.
The stop valve is used and actuated in the following manner :-
As shown in the drawings (Sheet No. 1.) the three stop valves are closed. The
boiler stop valve 4. is first lifted by rotating the hand wheel 16, and thus
simultaneously raising the valve 6. by means of the lever 17. pressing against the
collar 18. The cock 15. being so adjusted as to maintain connection between the
pipe 11. and cylinder 7; immediately the steam pressure in the said pipe 11.

page_text: becomes sufficiently great the piston 8. and the valve 6. rises still further and the
lever 17. is thrown on one side by means of the cone 19. and semicircular recess 20.
in the lever, said lever being free to rotate about the axis of the stud 21. A leak
hole 22. may be in the valve 6, in which case the lever 17. may or may not be used.
The function of the leak hole is to equalize the steam pressure on both sides of the
valve and thus allow of its being entirely opened by fluid pressure, which would be
of importance should the said valve 6. be closed by a lowering of steam pressure
in the pipe due to the engine suddenly "running away."
Suppose now it were necessary to stop the engine from any station-say from
cock 15.-said cock is adjusted until communication is closed between 7. and 11.
and opened between 7. and the atmosphere, the reduction of pressure immediately
allowing the valve 6. to close, by the action of the boiler steam, the spring 23.
assisting, and the "cataract or regulating orifice 26. governing the speed with
which said valve comes down upon its seat. If the steam pipe 11. or the engine
cylinder were to burst; the sudden diminution of steam pressure would cause the
valve 6. to act in a similar manner to that aforesaid.
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 combination of parts constituting my improved stop valve for boilers
and the steam pipes connected therewith, substantially as hereinbefore illustrated
and described.
(2) The use of the small pipe 12. and the cock or cocks 15. for stopping the
engine from the various stations 14. as hereinbefore described with reference to
Figure 3. of the accompanying drawings.
(3) The use of the leak hole 22. substantially as and for the purposes set forth.
(4) The combination of parts for automatically closing the valve 6. should the
pipe 11. burst, as hereinbefore described.
Dated this 1st day of February 1892.
GEO. C. DOUGLAS & Co.,
41, Reform Street, Dundee, Agents for Applicant.