Improvements in or in connection with Smoke-consuming Hopper- fed Fireplaces of Variable Size.
Year: 1894

page_text: Date of Application, 23rd Oct., 1894-Accepted, 24th Nov.. 1894
COMPLETE SPECIFICATION.
Improvements in or in connection with Smoke-consuming Hopper-
fed Fireplaces of Variable Size.
I, GEORG WILHELM KRAFT of 10 An der Ziegelscheune, Dresden, Saxony,
in the Empire of Germany, Engineer, 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 :—
Inclined grates have heretofore been employed for smoke-consuming fireplaces
in which the coal supplied to a hopper above is supposed to slide down auto-
matically by its own weight at a rate proportioned to the rate of combustion of the
lower portion of the coal on the grate. While there is a bright fire in the grate
the smoke resulting from the gasification of the coal contained in the feed hopper
or in the shaft-like space connected thereto is consumed or burned up in its passage
over the incandescent coals.
But the inclined hopper-fed furnaces now in existence only act in an effective
manner when the dimensions of the grate are exactly proportioned to the amount
of fuel which is to be burned on it in a short time and when the operation of the
furnace grate or fireplace or the demands made is or are uniform.
Increasing or diminishing the intensity of the fire has been possible only to a
very slight extent with the so called smokeless or smoke-consuming furnaces or
fire-places hitherto employed and in such cases the proper combustion of the smoke
has always been disturbed.
So far as I am aware-no one has yet been successful in providing hopper-fed
furnaces or fire-places which would always equally well consume their smoke when
the rate of combustion has been varied that is to say at times more intense and at
times less intense.
Now my present invention has for its object to provide a smokeless furnace in
which the amount or rate of combustion can be varied without injuriously affecting
its smoke-consuming action.
In the accompanying drawings my present invention is illustrated in two
longitudinal sections, i.e.
Fig. 1 showing the apparatus adjusted for a small fire, and
Fig. 2 showing the same adjusted for a large fire.
The inclined grate A has at its upper end the feed hopper B which may be
made funnel-shaped at top to facilitate the charging of coal therein. This feed
hopper is made adjustable in such a manner that by moving it higher up or lower
down it will cover a greater or less area of the grate thus enabling the grate
surface or area to be varied.
The angle of inclination of the inclined grate is made such that the coal will not
be caused to roll quickly down but will advance gradually forwards in a uniform
layer (depending in depth on the clear passage opening through the hopper) on to
the open portion of the grate where it is burned whilst fresh coal that has already
become gasified or heated in the feed hopper slides down as required to thus
automatically replace the burned coal.
The angle of inclination being obviously a little more than the "angle of rest
i.e. a little more than the angle at which coal would not move itself.
It is obvious that the greater the area or surface of the grate that is not covered
by the feed-hopper the greater will be the amount of coal which can be burned at
one and the same time without affecting the combustion and gasifying processes
and consequently without affecting the combustion of the smoke in any way.

page_text: In the drawings the feed-hopper is shown actuated by means of a toothed rack C
on the underside thereof which engages with a toothed wheel D which in turn
engages in the toothed rack E fixed to the frame or support-this toothed
wheel D being adapted to roll in engagement with the toothed racks C and E on
both sides.
This toothed roller D is provided with a catch or pawl F to retain the hopper at
any desired point or any other well known or suitable mechanical device may be
-employed for this purpose.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. A hopper-fed fire-place or furnace in which the fuel feed hopper is capable of
adjustment so as to vary the area of the fireplace or grate and thus produce a
larger or smaller fire substantially in the manner and for the purposes herein before
set forth.
2. The combination with a fire-place such as A. of a fuel feed hopper such as B
adapted to be adjusted substantially in the manner and for the purposes hereinbefore
set forth.
3. The improved smoke-consuming fireplace combined and arranged to act
substantially in the manner and for the purposes hercinbefore described and
illustrated in the drawings hereunto annexed.
Dated this 23rd day of October 1894.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.