CERTAIN IMPROVED APPARATUS FOR PREVENTING STEAM BOILER EXPLOSIONS, AND FOR DECOLORIZING THE GASEOUS PRODUCTS OF FURNACE FUEL IN A STATE OF COM-BUSTION
Year: 1861

page_text: PROVISIONAL SPECIFICATION left by Frederick George Mulholland at
the Office of the Commissioners of Patents, with his Petition, on the
24th January 1861.
I, FREDERICK GEORGE MULHOLLAND, of No. 20, Great Orford Street,
Marlboro' Road, Chelsea, in the County of Middlesex, Civil and Mecha-
nical Engineer, do hereby declare the nature of the said Invention for
"CERTAIN IMPROVED APPARATUS FOR PREVENTING STEAM BOILER EXPLOSIONS, AND
FOR DECOLORIZING THE GASEOUS PRODUCTS OF FURNACE FUEL IN A STATE OF COM-
BUSTION," to be as follows:-
A float is connected by a rod to a piston working in a cylinder perforated to
allow the escape of steam whenever the float descends below a certain water
line regulated and determined so as to ensure the tube or tubes and flueways
being at all times covered or protected by water. To the head of the piston
rod a link is attached, the other end of same being keyed on to a spindle
(passing through an enlarged head-piece or bonnet having a steam and water-
tight division therein), to which motion being imparted (by the vertical action
of the piston rod) a valve is worked in one of the chambers, to which the
usual feed pipes are connected, or otherwise whenever convenient, and pre-
ferentially to a supplementary supply direct from the cistern or other source.
To the bonnet or cap a whistle is attached to warn the attendant of any
deficiency in the supply of water, and this alarum commences its action the
instant the float descends to such an extent as to draw the piston below the
head of the slots or perforations in the guide tube or cylinder. To prevent

page_text: the attendant from tampering with the internal arrangements the flanges of
the covering head-piece are locked together, whereby the apparatus is placed
solely in charge of the proprietor, or a confidential representative. The water
supply is conveyed by a feed pipe direct from the valve compartment, herein-
before described (through the steam space and water in the boiler) to a hollow
bridge or chamber, constructed so as to receive the fresh supply at that part
of the boiler in immediate contact with the furnace, and therefore more par-
ticularly subjected at all times to intense heat. To strengthen and stay the
boiler in this its weakest part and prevent disruption of the plates generally,
advantage is taken of the aforesaid arrangement to secure additional protection
thereto, and by obtaining an increased area of heating surface promoting the
rapidity of circulation, and consequently facilitating the generation of steam;
and these objects are attained by backing up the bridge with an extended
chamber or chambers (open at the sides and top to communicate with the
main body of water in the boiler), a passage being left therein for delivering
the necessary supply of atmospheric air to support combustion. The ash-pit
being closed in and the air supply conveyed by metal or fire-clay tubes or
chambers to the hollow and inverted bridge; becomes highly rarified in its
passage thereto, and by acting on the surface only of the fuel the bituminous
products of each fresh charge of coal are necessarily forced through the incan-
descent body below, whereby they become purified and decolourized. Whenever
the burning properties of the fuel are deteriorated by the presence of bitumi-
nous shale or other foreign matters the furnace door or doors are fitted, so
that on opening them to stoke or charge one or both must come in contact
with a tappet or lever attached by a rod, chain, or other connection with a
tap, whereby a jet of steam is liberated or ejected into the chimney before the
smoke reaches it, and the ascent of colored gasses (if any) is arrested and their
precipitation ensured.