IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES
Year: 1856

page_text: by the Act.)
PROVISIONAL SPECIFICATION left by John Hopkins at the Office of the
Commissioners of Patents, with his Petition, on the 3rd October
1856.
I, JOHN HOPKINS, of No. 5, Lower Oxford Street, Whitechapel, in the
County of Middlesex, Builder, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES," to be as
follows:-
The objects of my Invention are, firstly, to promote the perfect combustion
of the fuel employed in furnaces and the gaseous products thereof, and thereby
to prevent the formation and emission of opaque or carbonaceous smoke; and
secondly, to prevent the furnace doors from becoming heated to an inconvenient
degree. And I propose to carry my improvements into effect in the following
manner: I construct the fore or dead plate or horizontal plate which is
between the furnace or feed door and the fire bars with an aperture or apertures
therein, so as to allow the atmospheric air which is permitted to enter at the ash-
pit to pass through. At the back of the furnace door and attached thereto is a
chamber of a semicircular or other suitable form, the same being constructed
of iron and perforated with holes, the top thereof being constructed of the
same material and perforated in a similar manner, and attached by means of
hinges, so as to be moveable from the outside of the furnace by means of any
suitable contrivance. Upon the furnace door being closed the said chamber is

page_text: brought into such a position as to be immediately over the before-mentioned
aperture or apertures in the fore or dead plate. On the air being allowed: to
enter through such last-mentioned aperture or apertures in the fore or dead
plate, it ascends and passes into and through the before-mentioned perforated
chaniber, when it is directed downwards upon the burning fuel, which is
resting upon the fire bars, by means of a deflecting plate fixed at a proper
angle to the upper part of the furnace. Another effect of this deflector is to
direct the current of air, which rushes in upon the furnace door being opened
for the purpose of feeding and stoking, downwards upon the fuel, and thus
preventing it from striking upon or affecting the upper portion of the furnace
or surface required to be heated.
In order more effectually to promote the perfect combustion of the fuel and
the gaseous products thereof, I place between the back end of the fire bars and
the bridge a grate or smaller set of bars at a lower level, (and constructed so
as to be readily moveable), the same being fed by the incandescent-fuel from
the main part of the furnace. The bridge is constructed of cast iron, and of
such a form as to contain a chamber opening at the lower part thereof to the
last-mentioned fire grate, the said chamber being supplied with atmospheric
air from the ash-pit; such air is heated in' its passage through the said chamber,
and then passes through suitable apertures in the upper part of the bridge,
where it assists in maintaining the combustion of the fuel and the gaseous
products thereof, and prevents the formation of opaque or carbonaceous
smoke.
A material advantage resulting-from my improvements-is, that no cooling of
the boiler or other surface required to be heated is occasioned by the admission
of a body of cold air, but the required processes can be carried on without those
interruptions and disadvantages attendant upon a variation of temperature,
while the effect of the admission of the air from the ash-pit through the fore
or dead plate, as before-mentioned, is to refrigerate the space behind the furnace
door, thereby preventing the same from becoming heated to an inconvenient
degree.
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