IMPROVE- MENTS IN VACUUM VALVES AND SAFETY VALVES
Year: 1855

page_text: (This Invention received Provisional Protection, but notice to proceed with the
application for Letters Patent was not given within the time prescribed
by the Act.)
PROVISIONAL SPECIFICATION left by Edward Taylor Bellhouse and
Thomas Cowburn at the Office of the Commissioners of Patents, with
their Petition, on the 28th February 1855.
We, EDWARD TAYLOR BELLHOUSE, of the Eagle Foundry, Manchester, in
the County of Lancaster, Engineer, and THOMAS COWBURN, of the same Place,
Engineer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN VACUUM VALVES AND SAFETY VALVES" to be as follows:-
This Invention relates to certain peculiar constructions and arrangements of
oscillating safety and atmospheric valves for steam boilers and other purposes
where safety or atmospheric valves are employed, and consists, according to
one modification, of a compound vacuum and float valve, which is opened and
allows the steam to escape from the boiler, or atmospheric air to enter the same,
if a vacuum be formed therein, so soon as the level of the water in such boiler
becomes dangerously lowered. To effect this object, the valve itself rests upon
a concave or spherical seating, and receives the steam pressure on its upper
surface; it is connected by means of a forked rod with a horizontal or nearly
horizontal tubular lever, near to one end of which it is ridgidly secured, thus
forming a bent or elbow lever, the vertical arm of which is attached at its
upper end to the valve, whilst to one end of the horizontal tubular arm is
attached a float. In the interior of the tubular arm of the lever are placed

page_text: one or more metal balls or running weights, the object of which will be
herein-after described.
The following is the mode of action of this valve:-When the water in the
boiler is at its proper or safe level, the tubular arm of the lever will be slightly
inclined towards the valve, the running weights in such arm being at the end
furthest from the float, and the upright arm connected with the valve will be
vertical; but when the level of the water gets dangerously low, the float on
the end of the tubular arm will descend, and incline the arm so as to cause the
weights to run to the lower end of it, which weights will still further depress
that end of the lever, & by their impetus draw the upright arm slightly out of
the perpendicular, which will thereby actuate the valve, by inclining it on its
concave or spherical seating, and afford space at each side of the valve for the
escape of steam into the blow-off' pipe; this escape steam may be directed into
the furnace to put out the fire, if required. On the water resuming its proper
level, the float will be raised again, and the weights will roll back to the other
end of the tubular arm, thereby bringing the upright arm into a vertical
position, and so closing the valve. A stop is placed so so as to prevent the float
from being unduly elevated, should the level of the water be higher than
absolutely necessary in the boiler.
Another application of the tubular lever arm, rolling weights, and floats
consists in adapting them to the working of safety and atmospheric valves on
the plates of furnaces or fire boxes, which valves, on being opened by the undue
lowering of the level of the water in the boiler, will allow atmospheric air to
enter the boiler if a vacuum be formed therein, or permit of the escape of a jet
of water and steam to be thrown on .to the fire, and so lower the heat, and
eventually reduce and check the generation of steam in the boiler. For this
purpose the tubular arm works on a fixed centre immediately over the valve,
and a short arm secured to the under side of the tubular arm is connected
to the valve cover; it will thus be obvious that when the tubular arm
descends at the float end, the short lever secured to its opposite end on the
under side will draw off slightly the valve cover from its concave seating, and
so admit of the escape of water and steam into the furnace, and allow of
atmospheric air to enter the boiler, if required. The valve cover may be fitted
with fusible plugs for greater safety, the holes for such plugs being tapped or
screwed into the cover, whereby the necessity of having a large head on the
plug, which always takes a longer time to melt, is obviated.
According to another modification of safety and float valve, the vertical arm
of the lever, herein-before referred to in the first-described arrangement of
safety and atmospheric valve, is jointed at its lower end to a short lever arm,

page_text: attached either to the upper or under side of the tubular lever, which in this
case works on a fixed centre. The rest of the apparatus remains the same as
herein-before described. When the level of the water in the boiler falls too
far, the tubular arm will descend at the end connected with the float, such arm
turning on its fixed centre at or near its opposite extremity, and moves at the
same time the short lever secured to it, which will have the effect of throwing
the upright arm out of the perpendicular, and so opening the valve. In this
arrangement the steam pressure may act upon the under side of the valve
in the ordinary manner, the valve in such case being a compound safety &
float valve, and may rest upon a concave or spherical seating, as before
described. This arrangement of actuating levers is equally applicable to the
first-described safety and atmospheric valve.