IMPROVEMENTS IN FURNACES
Year: 1854

page_text: LETTERS PATENT to William Davis, of the Old Kent Road, in the County
of Surrey, for the Invention of "IMPROVEMENTS IN FURNACES."
Sealed the 5th June 1855, and dated the 9th December 1854.
PROVISIONAL SPECIFICATION left by the said William Davis at the
Office of the Commissioners of Patents, with his Petition, on the 9th
December 1854.
I, WILLIAM DAVIS, of the Old Kent Road, in the County of Surrey, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
FURNACES" to be as follows:-
My improvements in furnaces refer to the admission of air at certain tem-
peratures for the better combustion of the gases evolved in the furnace, and
also to means of preventing the loss of heat by radiation. In order to facili-
tate combustion, I admit air at the furnace door, the supply at which point
may be regulated according to the state of the fire by opening or closing suit-
able valves, the air thus admitted to be of the natural state of the surround-
ing atmosphere. I also provide for the admission of heated air at or near the
throat or bridge of the furnace, by a peculiar formation and arrangement of the
furnace bars. I construct the bars hollow with an admission aperture under-

page_text: neath the front of the furnace. Every alternate bar has a curved projection
near the back end, which rises up to touch the bottom of the boiler or surface
against which the heat is playing. The bars intermediate of the former have
similar raised projecting parts, which are not carried so high as those of the
bars described, but about half the height thereof, and are then turned back-
wards towards the flue to about abreast of the bridge; the hollow channel of
the bar is continued up through this raised arm with an aperture of emission
at the back end.. The first-mentioned, bars, have also air emission apertures
carried backwards from the raised projecting arms. The air passing through
the hollow bars becomes heated and mingles with the gases at the throat of
the furnace, and assists the unrarified air admitted at the door in producing
a perfect combustion of the gases. To prevent the radiation of heat at the
furnace door, I apply three or four rows or series of arch. pieces between the
door and the fire. These arch pieces are fixed to the back of the door, with
the arch running in a vertical direction, and each supported therefrom by one
limb, the other limb of the arch being detached, and leaving a narrow space
for the passage of air. The rows of arch pieces are placed one behind the
other, so that the close part of one row of arch pieces covers the open spaces
of the alternate row. By this means free passage is afforded for the admission
of air, and all loss of heat by radiation prevented, by the disposition and inter-
position of the material of the arch pieces, and, further, the air spaces enclosed
by the arch pieces forming a non-conducting medium. I also prevent the loss
of heat by radiation underneath the fire bars, which I effect by means of rows
or layers of horizontal arch pieces placed beneath the bars; these arch pieces
are angular at the crown, so as to afford no resting place for the ashes. An
open space or passage is provided throughout the length of the arch pieces on
one side of each, which permits the free passage of air, and also allows the
ashes to fall through. The alternate layers of arch pieces are arranged so as
to break joint with each other, as before explained in reference to the furnace
door, and so as to effectually prevent loss of heat by radiation.