IMPROVEMENTS IN APPARATUS APPLICABLE TO STEAM BOILERS FOR LIBERATING STEAM THEREFROM EITHER IN THE EVENT OF EXCESSIVE PRESSURE, OR OF DEFICIENCY OF WATER FOR GIVING AUDIBLE SIGNALS IN THE LIKE CASES, AND FOR REGULATING THE SUPPLY OF WATER THERETO
Year: 1860

page_text: PROVISIONAL SPECIFICATION left by William Aldred and John Maynes
at the Office of the Commissioners of Patents, with their Petition, on the
11th February 1860.
We, WILLIAM ALDRED and JOHN MAYNES, both of Manchester, in the County
of Lancaster, Mill Furnishers and Agents, do hereby declare the nature of the
said Invention of "IMPROVEMENTS IN APPARATUS APPLICABLE TO STEAM BOILERS
FOR LIBERATING STEAM THEREFROM EITHER IN THE EVENT OF EXCESSIVE PRESSURE,
OR OF DEFICIENCY OF WATER FOR GIVING AUDIBLE SIGNALS IN THE LIKE CASES, AND
FOR REGULATING THE SUPPLY OF WATER THERETO," to be as follows:-
The said Invention consists partly in a novel combination and arrangement
of the parts of a float apparatus; and partly in various combinations of such
float apparatus with other apparatus or means subservient to the purposes
specified. The float apparatus consists of a weight or float, or floating weight
confined in a case or receptacle elevated above the surface of a fluid exposed
to the action of the steam, the fluid being in some cases mercury, in others the
water of the boiler. The interior of the case or receptacle is in communication
with the body or reservoir of fluid by means of an open tube or pipe extending
downwards therefrom, and having its lower extremity immersed in and terminating
below the regular or working level of the fluid. The pressure of the steam upon

page_text: the surface of the fluid forces a portion of the latter up the pipe or tube, and
fills the case or receptacle so as to raise and sustain the float or weight.
Upon the subsidence of the fluid in the reservoir below the extremity of the
pipe or tube, the communication between the case or receptacle and the fluid
is broken, and the fluid in the case is evacuated through the pipe, leaving the
weight or float to descend for want of support. From this alteration in the
position of the float or weight dependent upon the change in the level of the
fluid we derive by combinations with other apparatus a means of opening
valves or governing mechanism applicable to various purposes connected
with the economy of steam boilers as herein-after mentioned.
For liberating steam under excess of pressure we apply a weight or float
such as before described, the suspending fluid used being mercury contained
in a trough or reservoir, which is liable to be emptied through a vertical pipe,
of altitude sufficient to contain a column corresponding to the pressure to
which the steam is to be limited. Upon the steam exceeding that pressure,
the case or receptacle is emptied by the mercury being blown out of the
trough through the vertical pipe, and the weight or float thereupon descends
and operates either as a counterpoise against part of the weight of the safety
valve, or as the agent for opening a stop-cock or valve to permit the escape
of steam.
For liberating steam in the event of a deficiency of water in the boiler,
we apply the weight or float in the same manner as before, so far as respects
its connection with the valve or stop-cock through which the steam is to
escape, but the suspending fluid is the water of the boiler into which the open
end of the tube or pipe is immersed to the depth of the lowest level to which
the water is to be allowed to subside.
For giving an audible sigual or alarm in the event of excessive pressure,
we use the weight or float suspended in mercury in the same manner as in the
first-mentioned case, and cause the descent of the weight or float when the
mercury is withdrawn to open a valve which admits steam to a steam whistle.
For giving an alarm in case of deficiency of water, we apply a weight or
float suspended in water raised from the boiler as in the secondly mentioned
instance, to open the valve of a steam whistle by its descent.
For regulating the supply of water we employ a float or weight suspended
in water raised from the boiler to open by its descent a valve which admits
steam over a supply of water contained in a steam and water-tight tank or
cistern over the boiler, and communicating therewith by a pipe and a valve
opening towards the boiler so as to prevent regurgitation. The water in the

page_text: tank being by the admission of the steam placed in equilibrium descends into
the boiler by its own gravity.
Otherwise we use the weight or float similarly suspended to open by its
descent a valve admitting steam to a small feed pump engine which pumps
water into the boiler until the level is sufficiently restored to cut off the steam
by again filling the case or receptacle raising the float, and thus re-closing
the valve.