Improvements in or connected with Furnaces.
Year: 1899

page_text: Date of Application, 31st Oct., 1899-Accepted, 29th Sept., 1900
Improvements in or connected with Furnaces.
I, WALTER PAUL GRATH, of 510, Pine Street, St. Louis, in the State of
Missouri, United States of America, Brick Manufacturer, 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 furnaces and has for its principal objects to utilize
coal slack as fuel and to avoid the generation of dense clouds of smoke. To
these ends, my invention consists in providing the combustion chamber of the
furnace with shelves or platforms for supporting the fresh slack and in so
arranging the draft flues that such slack will be thoroughly coked before it is
applied to the fire grate.
In the accompanying drawings, which form part of this specification,
Figure 1 is a front elevation of a furnace embodying my invention,
Figure 2 is a cross section thereof on the line 2-2 of Figure 3, and
Figure 3 is a horizontal section on the planes indicated by the line 3-3 of
Figure 1.
Like symbols refer to like parts wherever they occur.
The outer walls 1 and roof of my furnace are built in any usual way of brick
or other suitable material to enclose the grate 2 and the combustion chamber.
From one or both of the side walls, shelves 3 extend horizontally to form brackets
or platforms which are located a convenient, distance above the grate. The
inner edges of these shelves or platforms are preferably supported on walls 4
having openings therein or on columns arranged to leave spaces between them.
Such columns or walls thus constitute a fire box or convenient means for con-
fining the fuel but allows the products of combustion to enter and circulate
freely in the spaces or flues under the shelves, which spaces are in effect lateral
extensions of the combustion chamber. As the shelves are imperforate the
spaces in the combustion chamber above the shelves are cut off from the supply
of air and constitute coking chambers. The outer rear wall is protected by a
fire wall 5 having an opening 6 in its upper middle portion, and a smaller
opening 7 below each side shelf communicating with the flue or extension of the
combustion chamber below said shelf.
The front of my furnace is built with openings therein communicating respec-
tively with the fire box, each of the coking chambers at the sides thereof, the
ash pit below the grate and each of the side flues below the coking chambers:
and a door is provided for each of these openings. The outer rear wall has a
single outlet opening 8 for the hot products of combustion.
The operation of my device is initiated by building a fire of any suitable fuel
upon the grate in the fire box, and the slack to be used for fuel is piled on
the two shelves or platforms at the sides. The air necessary for combustion is
supplied through the ash pit and grate and the main products of the combustion
pass out through the opening in the fire wall, whence they pass through
the opening in the outer rear wall into the kiln, boiler or other
place. A portion of the products of combustion however pass through
the openings in the sides of the fire box into the extensions or flues below the

page_text: respective coking chambers and thence through the openings 7 in the inner
rear wall, into the rear flue and thence out through the opening 8 in the outer
rear wall along with the main volume which had taken the more direct course.
By this arrangement the slack in the coking chambers is not only exposed
above to the direct heat in the fire box but as the shelves or platforms which
constitute the bottom of the coking chambers are the tops of the side flues or
extensions of the combustion chamber as well such slack is exposed below to
the heat in the flues or chamber. Thus all portions of the slack are sufficiently
heated to become thoroughly coked and the hot gases generated therefrom are
driven off into the draft of air coming up through the grate and are consumed.
When new fuel is required for the firebox the coke thus formed is raked off
the side shelves in one or more large masses on to the grate and a supply of fresh
slack is shovelled into the coking chambers.
While the construction represented in the drawing is the best form of my
device my invention admits of considerable modification. For instance, instead
of having one fire box between two shelves there may be only one shelf extend-
ing from the wall or there may be one central platform between two fireboxes,
and in either case satisfactory results are obtained by providing openings in
the side or sides of the firebox for the free radiation of heat and circulation
of products of combustion without providing any special outlet therefrom. So,
also, where no inner walls are used for limiting the fuel or where the openings
therein are sufficiently large, no special outlet opening need be made under the
shelves or platforms.
My furnace is specially designed for burning coal slack and is applicable for
heating kilns, boilers or other furnace uses. Its most important advantages are
that it thoroughly cokes all the slack before burning the same, whereby the
maximum heating value of the fuel is obtained, smoking is avoided and the fire
is easily regulated.
The present invention is conveniently adapted to furnaces for brick-kilns.
It will be seen that the coking chambers of the present invention are not exposed
to the intense heat of the fire but are arranged at the sides of the combustion
chamber completely cut off from the air and heated mildly from below as well
as from above. Thus the generation of gases is more even and uniform and the
quality of coke is superior and therefore the fire itself is more uniform.
It will further be seen that the coking chamber communicates along its entire
length with the combustion chamber. Therefore the gases generated by the coking
operation escape into the combustion chamber where they are thoroughly mingled
with the gaseous products of combustion and air. These gases unite of course
with the hot air but such union is delayed by reason of the presence of the
gaseous products of combustion which dilute and interfere with them but keep
them hot and thereby ensure their union. The result is that the combustion of
a considerable part of the gases is not effected in the combustion chamber but at
a considerable distance therefrom, according as the dilute air comes gradually
in contact therewith. The heat also is nearly uniform for a considerable dis-
tance from the combustion chamber. In fact, combustion continues to take
place so far along in the flues that the temperature in all parts of a kiln connected
thereto is much more nearly uniform than has heretofore been attainable, and
bricks burned therein are of more uniform quality and colour.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. A furnace comprising outer walls enclosing a grate and a combustion
chamber and having a raised imperforate platform arranged under the roof of the
combustion chamber and extending horizontally from a wall thereof so that a mass
thereon may be pushed off onto said grate, the space beneath said platform being
open to the products of combustion, and the space above said platform being con-

page_text: tinuous with the combustion chamber but cut off from the supply of air, sub-
stantially as and for the purpose set forth.
2. A furnace comprising outer walls, a firebox therein having a separate wall
with openings therein, and a shelf extending from said firebox wall to the outer
wall, said furnace being provided with a flue for the main draft from the com-
bustion chamber and a secondary outlet flue communicating with the chamber
beneath said shelf, substantially as and for the purpose set forth.
3. A furnace comprising outer walls, a firebox therein having separate side
walls provided with outlet openings, a platform on each side of the firebox
extending from the top of the firebox wall to the outer wall, said furnace being
provided with a main draft flue opening into the rear end of the combustion
chamber and secondary draft flues communicating with the space beneath the
side platforms, substantially as and for the purpose set forth.
4. A furnace comprising outer walls, a firebox therein having a fire wall at the
rear end thereof provided with the main outlet opening for the products of com-
bustion, and having separate sidewalls provided with secondary outlet openings,
and platforms extending from the sidewalls of the firebox to the outer walls,
the chambers below said platforms communicating with the space back of the
firewall, the outlet opening for the products of combustion being located in the
rear wall, substantially as and for the purpose set forth.
Total thin 21 at J. of Ontation 1000
J. G. LORRAIN, M.I.E.E., M.I.Mech. E.,
Norfolk House, Norfolk Street, London, W.C.,
Chartered Patent Agent,