AN IMPROVED COMBINED LOW WATER ALARM AND SAFETY VALVE FOR STEAM BOILERS
Year: 1881

page_text: LETTERS PATENT to George Wilson, of Old Kent Road, in the County of
Surrey, for an Invention of "AN IMPROVED COMBINED LOW WATER ALARM
AND SAFETY VALVE FOR STEAM BOILERS."
PROVISIONAL SPECIFICATION left by the said George Wilson at the Office
of the Commissioners of Patents on the 31st January 1881.
GEORGE WILSON, of Old Kent Road, in the County of Surrey. "AN IMPROVED
COMBINED LOW WATER ALARM AND SAFETY VALVE FOR STEAM BOILERS."
This Invention consists of a small dome or chamber fixed on top of the boiler,
the said chamber being divided by a diaphragm into an upper and lower chamber,
of which the former has a whistle fixed upon it and the latter is in permanent
communication with the steam space of the boiler.
The low water alarm valve is seated in the diaphragm and opens downwards,
and is formed on a stem rising through the top of the boiler shell, and having a
float attached to its lower end, whereby the water is kept closed so long as there is
sufficient water in the boiler, but opened by the descent of the float when the
water falls below the proper level, whereupon steam is admitted to the upper
chamber and the whistle sounded. The safety valve, which is also seated in the
diaphragm, opens upwards, and is loaded by means of a spring adjusted by a
perforated screw, according to the pressure at which it is desired that the valve
shall operate. The chamber has a removable cover for inspection, but which may
be locked to prevent tampering with the valves.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Wilson in the Great Seal Patent Office on the 30th July
1881.
GEORGE WILSON, of Old Kent Road, in the County of Surrey. "AN IMPROVED
COMBINED Low WATER ALARM AND SAFETY VALVE FOR STEAM BOILERS."
My said Invention relates to a peculiar combined arrangement of safety valve
and low water alarm to be used in connection with steam boilers, for the purposes
of calling attention to excessive pressure or deficiency of water therein whereby
many boiler explosions could be timely prevented.
For this purpose I provide a small dome or chamber fixed on the top of the
boiler, the said chamber being divided by a diaphragm into an upper and lower
chamber, of which the former has a whistle fixed upon it and the latter is in
permanent communication with the steam space of the boiler.
The low water alarm valve is seated in the diaphragm and opens downwards,
and is formed on a stem rising through the top of the boiler shell, and having a
float attached to its lower end, whereby the valve is kept closed so long as there
is sufficient water in the boiler, but open by the descent of the float when the
water falls below the proper level, whereupon steam is admitted to the upper
chamber and the whistle sounded. The safety valve, which is also seated in the
diaphragm, opens upwards, and is loaded by means of a spring adjusted by a
perforated screw, according to the pressure at which it is desired that the valve
shall operate. The chamber has a removable cover for inspection, but which may
be locked to prevent tampering with the valves.
And in order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the accompanying Drawing, which represents a part transverse section of a steam
boiler with my improved safety valve and low water alarm apparatus applied
thereto.
A is part of a steam boiler, of any suitable known construction, on which is
mounted the metallic dome B, of any convenient shape, which may be supported
by a saddle piece C or other similar device.
The interior of the dome is formed with a diaphragm D, so as to provide suitable
seats and bearings for the valvular mechanism before referred to.
H is a conical lift valve seated at h within the tubular chamber K, and which
is suitably loaded by a spiral spring I, and capable of adjustment by means of a
screw cap or the perforated plug k
The valve H is capable of reciprocating in a vertical plane under pressure, so as
to allow the excessive steam to pass from the boiler into the chamber K, and find
its exit therefrom by the lateral passages m and also through the perforated plug
at k¹, both communicating with the outer enclosing dome B. By raising or lowering
the plug or screw cap by means of a spanner the loading of the valve H may be
varied to suit the requirements of working pressure to be maintained within the
boiler, and beyond which limits it may not be desired to exceed.
1
The second conical valve F, capable of opening downwards, is held to its seat f¹
under normal circumstances by the elevation of the float E, which is connected to
the valve by the rod f, and which falls with the height of the water level within
the boiler. The rod passes through an aperture c formed in a sleeve F' passing
through the shell of the boiler, and of sufficient size to allow free passage of the
steam around the said rod to the interior of the dome. The rod working in
guides f³ is provided with a suitable stop formed by a pin f² working in a slot in
the sleeve Fi or other similar device to prevent the valve F dropping too far,

page_text: so as to cause it to permanently leave the passage which it is intended to control
or from falling with its rod bodily into the interior of the boiler when the water is
removed therefrom.
G is a whistle or other suitable alarm mounted on the dome B, and communi-
cating with the interior thereof by the passage g, and through which the valves
may be lubricated.
Now assuming excessive steam pressure to have been generated and accumulated
within the boiler, which elevated abnormal pressure correspondingly exists within
the cavity or chamber L through passage c communicating therewith, the valve H
is immediately raised so as to relieve such pressure.
Steam having thus passed the valve it travels through the chamberk and by the
passages m and to the upper cavity M, and from whence it makes its final
escape through g, so as to blow or actuate the whistle or alarm G and so call
attention to the dangerous impending state of affairs. All the moving parts being
enclosed and secured within the dome or casing it prevents the possibility of any
one tampering with the same.
Now conversely assuming the pressure to be fluctuating through insufficiency of
water in the boiler contingent upon negligence, or the water therein allowed to
get low from any other cause (as would be the case if the injector failed to properly
work), then the float E having similarly followed the subsidence of the water line
or level, it effects by its connection the downward opening of the valve F, thereby
permitting the escape of sufficient pressure of steam through M to blow the
whistle or sound the alarm G, so as to attract attention to such condition of the
boiler.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that what I consider to be novel and original,
and therefore claim as the Invention secured to me by the herein before in part
recited Letters Patent is,-
The peculiar combination of safety valve and low water aların apparatus,
constructed, arranged, and operating substantially as and for the purposes herein-
before described and illustrated in the accompanying Drawing.
In witness whereof, I, the said George Wilson, have to this my Specification,
set my hand and seal, this Twenty eighth day of July, One thousand eight
hundred and eighty one.
GEORGE WILSON. (L.S.)