Improvements in Furnaces for Steam Boilers.
Year: 1891

page_text: Date of Application, 16th June, 1891-Accepted, 18th July, 1891
COMPLETE SPECIFICATION.
[Communicated from abroad by ROBERT LOUDON WALKER, of Boston, Massa-
chusetts, United States of America.]
Improvements in Furnaces for Steam Boilers.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent.
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby
declare the nature of this invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:-
My invention relates to that class of furnaces in which the main body of fuel is
coking while a smaller body of fuel is incandescent, the products of combustion
from the coking fuel, being deflected by a hanging wall of fire brick, or like
refractory material which is at a high heat over the incandescent fuel.
My invention is designed to improve the construction of the furnaces described
in U.S. Patent No. 203666 granted to Stanton and Hutchinson and dated
May 14th 1878; and consists in forming the furnace proper, by which I mean the
parts above and below the grates, commonly called the "fire box" and "ash pit'
with side walls, which are parallel at, but diverge above the fuel; as will be herein
after described.
In the accompanying drawing,
Figure 1 is a longitudinal section; and
"
Figures 2 and 3 are cross sections on the corresponding section lines of Figure 1,
illustrating my invention in its proper form.
A is the boiler; supported in the usual way between the two main side walls of
the brick work of the furnace. These side walls are marked B B¹, but heretofore
the fire box and ash pit have been formed by the parallel side walls B B', as
indicated by the dotted lines in Figures 2 and 3; and the main feature of my inven-
tion is the addition to these side walls of the parts bb' inside those dotted lines;
thereby diminishing the width of the fuel bed; and forming a larger space above
the fuel bed, to admit of the expansion of the gases, at front and at rear of the
hanging wall or deflector, C; the gases above the coking fuel, which are the
products of the comparatively slow combustion of that fuel mingled with atmo-
spheric air, eddying about in the chamber which is the front portion of the fire box,
and passing under the deflector C, and over the incandescent or quick burning fuel,
in the rear portion of the fire box, when they again eddy about as they pass over
the bridge wall D, on their passage to the stack.
In furnaces of this class the deflector C becomes highly heated, the grate F is a
shaking grate, or such that it is adapted to keep the fuel supported by it open to
allow a draught sufficient to keep the fuel incandescent; and the grate F' is of any
usual construction, as it supports the slow burning or coking fuel; as will be well
understood without further description; but where the fuel bed is as wide as any
other part of the furnace, it is impossible to maintain the proper balance between
the coking and the incandescent fuel, for the best results; and after a large
experience with furnaces of this class I have discovered that the area of the fuel
bed should be considerably less than the area of the furnace in a horizontal plane
above the fuel bed.
In the drawings I have shown the width of the fuel bed less than the diameter
of the boiler; and this is important for the best economy of fuel.
It will be understood that I do not claim the broad principle of a fuel bed
divided into two parts; nor such a bed combined with a deflector to direct the
products from the green or coking fuel upon the incandescent fuel; my invention
being an improvement upon furnaces of that class the main feature of which

page_text: improvement is the relation of the area of the fuel bed to the area in a horizontal
plane of the chamber which is divided into two parts by the deflector, and the
outlet from which is over the bridge wall, allowing for the expansion of the gases
in both chambers, but with a contracted outlet from each chamber; and the diameter
of the boiler should always be materially greater than the width of the fuel bed,
for the best results with ordinary forms of boiler.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me
by my foreign correspondent, I declare that what I claim is :-
In combination the boiler A, supporting walls B B', inner additional walls bb¹,
and bridge wall D, arranged to form a combustion chamber; deflector C, dividing
that chamber into two chambers each with a contracted outlet; and grates F F',
one to support the coking or slow burning fuel, the other the incandescent fuel;
the area of the fuel bed being materially less than the area of the combustion
chamber in a horizontal plane above the fuel bed, all substantially as described.
Dated this 16th day of June 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.