IMPROVEMENTS IN THE COMBUSTION OF FUEL AND IN THE FURNACES AND APPA- RATUS EMPLOYED THEREIN
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by James Hiscocks at the Office of
the Commissioners of Patents, with his Petition, on the 4th January
1866.
I, JAMES HISCOcкs, of Chicksgrove Mills, Tisbury, in the County of
Wilts, Miller, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE COMBUSTION OF FUEL AND IN THE FURNACES AND APPA-
RATUS EMPLOYED THEREIN," to be as follows:-
This Invention relates to a peculiar arrangement of furnace and apparatus
connected therewith, which may be applied to a steam boiler or to other pur-
poses where economy of heat and fuel is important, and consists, according
to one modification, as applied to an ordinary Cornish boiler for example,
in constructing in front of the boiler two furnaces side by side in brick-
work, each furnace communicating alternately with the central flue of the
boiler; this is accomplished by the employment of a reversible damper, which
is situate between the two furnaces, and is counterbalanced so as to swivel
freely upon centres; it is turned over towards one or the other of the two
furnaces so as to shut off entirely for the time being either of such furnaces
from the central flue of the boiler. The furnaces are fired alternately,

page_text: that which is being fired being the one which is cut off by the damper
from the boiler flue. The smoke and products of combustion from this
furnace pass down through an opening left for that purpose between the
two furnaces, and thence proceed underneath and up through the grate
bars and fuel of the second furnace, which is in an incandescent state,
whereby they are effectually consumed before entering the flue of the
boiler. Beneath the damper above referred to there is a second reversible
damper, which may or may not be perforated as required, the object of such
damper being to direct the air which supports combustion through the
grate of the furnace which has last received a supply of fresh fuel. Both
these dampers may be worked by lever handles outside the face of the
setting, and the handle of the last-named damper is capable of being set
at any desired position so as to direct either the whole or only a greater
portion of the air through the newly fed furnace. The ash-pit to the two
furnaces is closed, as are also the furnace doors, excepting when supplying
passes into
fuel, and the air which supports combustion is heated before it
and through the furnaces by the gases and products of combustion whilst
on their way to the chimney. This I accomplish by the following arrange-
ment The products of combustion having traversed the central flue of
the boiler return towards the front by a flue underneath the bottom of the
boiler, then descend into a chamber in which is fitted a series of air tubes
opening at one end into the back of the closed ash-pit and at the other end
into a second chamber. Another series of tubes is fitted into this second
chamber, which tubes open into the first chamber at one end and into a
The third chamber is similar to the
third chamber at their opposite end.
first, having a set of tubes therein which open at one end into the second
chamber, whilst their opposite ends are open to the external atmosphere.
The action of this air-heating arrangement is as follows:-The highly
heated products of combustion on entering the first chamber circulate
round the tubes therein and impart heat thereto, they then pass through
the interior of the tubes in the second chamber, which also become highly
heated, and finally enter the third chamber, and after circulating round the
exterior of the tubes therein they are drawn away through a suitable
escape flue by the action of an exhausting fan, which creates the required
draught without the necessity for a high chimney. As the fresh cold ai
passes through the tubes in the third chamber and enters the second
chamber, wherein it circulates round the exterior of the heated tubes
therein, and proceeds through the interior of the highly heated tubes in

page_text: the first chamber, it follows that its temperature is considerably elevated
by the time it enters the back of the ash-pit and arrives at the furnaces.
Suitable plug holes are made in the tube plates of the first and third
chambers with a view to affording facility for cleansing the interior and
exterior of the tubes in the three chambers.