IMPROVEMENTS IN STEAM BOILERS FOR PREVENTING EXPLOSION THEREOF
Year: 1855

page_text: PROVISIONAL SPECIFICATION left by John Drury at the Office of the
Commissioners of Patents, with his Petition, on the 20th April 1855.
I, JOHN DRURY, of Paddock, near Huddersfield, in the County of York,
Machine Maker, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN STEAM BOILERS FOR PREVENTING EXPLOSION THEREOF " to be
as follows:-
These improvements are comprised under four separate heads, and consist,
firstly, of a novel mechanical -arrangement for giving notice by a whistle
when there is too small a quantity of water in the boiler.
Secondly, a novel mechanical arrangement for extinguishing the fire when
there is too small a quantity of water in the boiler, said arrangement being
designed as an auxiliary security to the boiler when the notice given by the
whistle has either not been heard or has failed to be attended to.
Thirdly, a novel self-acting mechanical arrangement of feed valves for
admitting water into the boiler when the feed pump ceases to perform its
office properly.
Fourthly, a novel mode of arranging within the boiler the float employed
for determining the height of the water in the boiler, whereby such said float
is caused to operate upon the several mechanical arrangements above referred
to, under 1st, 2nd, and 3rd heads of these improvements, when there is too
small a quantity of water in the boiler, from whatever cause such deficiency
may arise.

page_text: The nature of these improvements will, however, be better understood by
the following general description of the means by which they may be effected,
that is to say:--
Under the 1st head of these improvements, the arrangement consists in
adapting to the top of the boiler a casting, containing two valves fixed upon a
rod working steam-tight in a stuffing box upon the top of the boiler; the
lower end of said rod passes into the boiler, and has a small weight fixed
upon the end thereof. In connection with the aforesaid valves are certain
outlets, namely, one from the boiler to the space between the valves, another
outlet below the lowermost valve, and a similar one above the uppermost
valve; these last-mentioned outlets unite in one common outlet, to the top of
which a bell or whistle is attached, so that when the valves are raised by
the means herein-after described, the steam from the boiler acting upon the
edge of the bell or whistle will give an alarm, and thus call the attention of
the attendant.
Under the 2nd head of these improvements, the arrangement consists in
adapting to the top of the boiler another casting, containing two other valves
fixed upon a rod with a weight attached thereto, similar to that before referred
to. The difference between this casting and the former one consists in so
forming and placing the inlet pipe which is within the boiler as that the
bottom thereof reaches to within a short distance of the bottom of the boiler,
whilst the outlet pipe passes through the bottom of said boiler, so that when
the valves are raised by the means herein-after described, the pressure of the
steam upon the surface of the water in the boiler will force the water through
the outlet pipe, and thus extinguish the fire which is beneath it.
Under the 3rd head of these improvements, the arrangement consists in
adapting to the top of the boiler another casting, containing three valves; this
casting is formed with two outlets, one of which is in connection with a feed
pump of the ordinary kind, and the other has a pipe connected thereto which
passes into the boiler in the manner usually practised. The three valves are
fixed upon a rod which works steam-tight through the top of the boiler, and
the lower end of said rod is formed forked, and embraces a lever by a pin
passed through the same. The fulcrum of the said lever is a pin passed
through the forked end of a strong stud securely fixed inside the top of the
boiler; the aforesaid lever should be sufficiently long as that when raised it
will touch the weights which are affixed to the valve rods of the arrange-
ments described under the 1st and 2nd heads of these improvements. The
other and opposite end of such said lever is furnished with a float, working in
a small vessel placed beneath it, and employed for giving a steady motion to

page_text: the float, said vessel forming an important feature in these improvements.
Now, supposing the boiler to be charged with water to its proper height, it
will appear obvious that so long as the level of the water is maintained, the
before-mentioned arrangements which are at the outside of the boiler will
remain quiescent. But, supposing from any cause the level of the water to be
getting gradually lower, then the gravity of the float, aided by the pressure of
the steam thereon, will cause the opposite end of the lever to be raised, and
coming into contact with the first weight will lift it and the valves connected
therewith, and thus allow the steam from the boiler to pass the valves, thereby
sounding the whistle and giving notice to the attendant of a deficiency of
water in the boiler. And in the event of such notice being unheeded, the
lever continuing to rise will next come into contact with the second weight
and lift the valves connected therewith, the effect of which will be that the
pressure of the steam upon the water in the boiler will force the water there-
from through the outlet pipe on to the fire and thus extinguish it, and by these
means prevent the explosion of the boiler; and as the water continues to flow
out of the boiler, the float, descending lower, will now cause the lever to lift
the feed valves and thus charge the boiler with water; and as the float rises,
the lever descending will close the several above-mentioned valves, and the
fire may then be re-lighted and steam generated as before.