IMPROVEMENTS IN AND RELATING TO FURNACES
Year: 1885

page_text: I, HENRY CASWELL, of 1 Hall Green, Westbromwich in the County of Stafford,
foundry manager, do hereby declare the nature of my invention for, IMPROVEMENTS
IN AND RELATING TO FURNACES, to be as follows:-
The object of this invention is to devise means for the more perfect combustion
of fuel in furnaces, so as to avoid the emission of large volumes of smoke, and to
effect greater economy.
According to this invention, the furnace proper is formed as a hopper provided
preferably with a hinged or other lid at the top thereof-The fire bars are carried
downwards, in a backwardly slanting direction, from a bearer upon which they are
hooked near the top of the hopper to a bearer near the bottom and towards the
back thereof The furnace is entirely surrounded by walls, either of brickwork or
other refractory material or of metal, or partly of brick work or other refractory
material and partly of metal, except that a flue opening is formed at the back of
the lower part of the hopper for communication with the flues or other parts into
which the heat is to be conveyed, such, for instance, as the flues of a boiler or the
puddling chamber of a puddling furnace-A door is also provided through the
bottom of the front of the furnace for the removal of the ashes, which are drawn
away from time to time from under the lower ends of the bars forming the bottom
of the hopper-A suitable stop is formed to prevent the bars from being lifted up
off the top bearer during the removal of the ashes-A wedge-shaped space occurs
between the outer edges of the bars and the inside of the front wall of the furnace,
and into this space is brought one end of a pipe or flue which passes through
the boiler or other flues or chambers from the furnace, and which is in com-
munication at its other end with the exterior air-The air for the furnace is thus
drawn (by the chimney or other draught) first through the flue or pipe entering
the wedge-shaped space, aforesaid, and thence through the furnace proper, and such
air, being highly heated on its passage through such flue or tube, very greatly
assists in the thorough and complete combustion of the fuel within the hopper-
The air heating flue or pipe is preferably placed in the cooler part of the flue or
chamber in which it is itself heated, so as not to reduce materially the maximum
Price Rd71

page_text: temperature in such latter flue or chamber-The furnace bars may be formed
tubular, having their upper ends open to the atmosphere, so that air may pass
down through the bars and thus be heated before mingling with the incandescent
fuel at the bottom of the hopper, and act also in keeping the bars cool.
When two or more furnaces are being worked at the same time, the escaping
gases from one furnace may be forced (by means of a fan) or drawn by a sufficiently
powerful draught, through a second furnace, so that any combustible gases remain-
ing may combine at a high initial temperature with the combustible material in
the second furnace, and thus add materially to the efficiency and ensure the greater
economical working of such furnace; and this arrangement may be adopted in
conjunction with the air-heating flue described.

page_text: I, HENRY CASWELL, of 1 Hall Green, West Bromwich in the County of Stafford,
foundry manager, 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, reference being had, to the accompanying
drawings and the letters of reference marked thereon (that is to say):-
:-
The object of this invention is improved means for the more perfect combustion
of fuel in furnaces, so as to avoid the emission of large volumes of smoke and effect
greater economy of fuel.
According to this invention, the furnace proper is formed as a hopper provided,
preferably, with a hinged or other lid at the top thereof. The fire-bars form the
front side of the hopper, being carried downwards in a backwardly slanting
direction from a vertical plate at the front of the furnace to a position within a
few inches above the bottom of the furnace. These bars are supported in such
slanting position by a suitable bearer or bearers and are, preferably, formed
tubular, with their upper ends open to the atmosphere, so that air may pass down
through the bars and thus be heated before mingling with the incandescent fuel at
the bottom of the hopper and act also in keeping the bars cool. The bottom
bearer is, preferably, made of fire-brick or other refractory material with a slanting
opening therethrough for the reception and protection from burning of the lower
ends of the bars.. The furnace is entirely surrounded by walls, either of brickwork
or other refractory material or of metal, or partly of brick work or other refractory
material and partly of metal, and a flue opening is formed at the back of the lower
part of the hopper for communication with the flue or other part into which the
heat is to be conveyed, such, for instance, as the flue of a boiler or the puddling
chamber of a puddling furnace. A door is also provided through the lower part of
the front plate or wall of the furnace for the removal of the ashes, which are
drawn away from time to time from under the lower ends of the fire-bars.
A wedge-shaped space occurs between the front or outer face of the fire-bars and
the inside of the front plate or wall of the furnace, and into this space is brought
one end of a pipe or flue which passes through the boiler flue or flues or other flue
or flues or chamber, or through the hot brick work around such flue or flues or
chamber, or partially through the flue or flues or chamber and partially through
the brick work thereof, and this pipe or flue is in communication at its other end
with the exterior air. The air for the furnace is thus drawn by the chimney or
other draught, or is blown by a fan or other blower, through the flue or pipe, and
thus enters the wedge-shaped space, aforesaid, and passes thence through the fuel
in the hopper or furnace proper, and such air being highly heated on its passage
through such pipe or flue very greatly assists in the thorough and complete
combustion of the fuel within the hopper.
In the case of a boiler furnace or other furnace in which the temperature is not
extreme, the air heating pipe or flue is preferably placed in the cooler part of the
furnace flue or heating chamber so as not to reduce materially the maximum
temperature in such latter flue or chamber; but in the case of a puddling furnace
or other furnace in which a very high temperature is employed, or in which it is

page_text: inconvenient to arrange the heating pipe or flue within the furnace flue or heating
chamber, the air heating flue or pipe is carried within the brick work surrounding
the furnace flue or heating chamber. In the case, however, of a puddling furnace
or similar furnace, a part of such air heating pipe or flue may be carried within
the neck of the furnace, where the temperature is reduced.
In order to supply air as may be found desirable to the incandescent gases
passing from the hopper to the boiler flue or. other flue or heating chamber, a
transverse pipe connected with the air-heating flue or pipe is fixed within the
brickwork immediately over the flue from the hopper, and a number of jets or
nozzles project from such pipe to the back face of the brick wall between the
hopper and the boiler flue or other flue or heating chamber, and thus heated air
from the air-heating pipe or flue is admitted into such flue or chamber in streams
and readily mixes with the incandescent gases. The admission of air to the pipe
is regulated by a valve.
When two furnaces constructed in the manner above described, and with or
without the air-heating pipe or flue, are being worked at the same time, the
escaping gases from one furnace may be forced by means of a fan or other blower,
or drawn by a sufficiently powerful draught, through a second furnace, so that any
combustible gases remaining may combine at a high initial temperature with the
combustible material in the second furnace, and thus add materially to the
efficiency and ensure the greater economical working of such furnace; and a
corresponding arrangement for passing the waste gases from one furnace through a
second furnace may be adopted with the usual constructions of furnace by simply
closing in the ash-pit and bringing the waste gases from the one furnace into the
ash-pit of the other. If no air-heating pipe or flue is employed, some arrangement
must be adopted for admitting sufficient air to the furnaces, such as by ventilators
in the ash-pit doors, or by making the hollow fire-bars of sufficient size, or
otherwise.
My invention is illustrated in its application specially to a steam boiler furnace
by the drawings herewith, of which figure 1 is a longitudinal section through the
centre of the furnace and boiler, figure 2 a sectional plan on line x x of figure 1,
and figure 3 a transverse section on line y y of figure 1. The same letters of
reference occurring upon two or all of these views indicate corresponding parts.
A is the boiler, and B the grate or furnace proper, formed as a hopper with an
opening C at the top thereof provided with a door or lid D hinged so as to open at
the front. E E E are iron plates or an iron frame surrounding three sides of the
upper part of the furnace B, and F is a front plate extending from or about the
ground line to the level of the underside of the front of the lid D when the latter
is closed down. P is a plate across the top of the hopper and in which the opening
covered by the lid D is formed. G is a brick wall forming the back of the furnace
proper, and H is a flue from such furnace to the boiler flue. This flue H is arched
at the top as shewn by broken lines figure 3. J J are brick walls on each side of
the hopper. a a etc. are fire-bars and are preferably hollow, being conveniently
formed of wrought iron or steel tubes. These bars are passed down through a
slotted opening b, or through a series of holes, passing in an inclined direction
through the front plate F, and are held in position by means of sockets or collars
on their upper ends resting on an inclined shoulder c formed out from the front of
the plate F. The fire-bars are placed in an inclined position, as shewn, and are
supported at the lower end and middle by bearers & and e, respectively. The
bearer d is formed preferably of fire-brick or other refractory material, and the
lower ends of the bars pass down into and slightly through an inclined slot or holes
through the bearer by which means the lower ends of the bars are protected from
the intenser heat of the furnace. Figure 4 shews a front elevation of the bearer d
and the means by which it is supported and also the lower ends of the fire-bars.
This bearer is formed in two lengths each resting on a side wall of the hopper and
also on a brick support m, so as to leave room under each division for clearing ashes
from the grate. When a slot is formed through the bearer, the lower ends of the
.

page_text: bars may be distanced apart with a mixture of fire-clay and sand. The furnace
draught causes a current of air to pass through the fire bars, thereby tending to
keep them cool, and the air is thereby itself heated. This heated air is drawn
through the incandescent fuel in the lower part of the furnace B and increases the
efficiency of the furnace. K is an opening at the bottom of the plate F through
which the ashes are removed as they are drawn away from under the lower ends.
of the fire bars. This opening is provided with a door f. The inside of the plate F
is preferably lined by a brick wall L to protect it against the intenser heat from
the furnace. M M are flame bridges of the usual character. N N is an air pipe,
preferably of wrought iron, communicating with the exterior air at O, and passing
thence through one side of the boiler flue, as shewn, to the back end of the boiler
where it returns and thence traverses the other side of the flue and communicates
at S with the wedge-shaped space between the front of the fire-bars a a etc. and
the front plate F. In figure 1 this pipe is shewn, for convenience, by broken lines
passing in a slanting direction downwards to its connection at S. Air is drawn, in
the direction of the arrows, from the exterior air through the pipe N N into the
wedge-shaped space, aforesaid, and from thence passes in a highly heated state
through the incandescent fuel in the furnace B. R is an air-pipe carried within
the wall G, as shewn, and g g etc. are a number of nozzles in the side of the pipe
projecting therefrom to the hinder face of the wall G. This pipe R is connected
with the air-heating pipe N N. Heated air may thus be admitted from the
pipe N N through the pipe R and nozzles g g etc. in streams into the boiler flue
and thus thoroughly mix with the incandescent gases passing from the furnace B..
h is a sliding or other shutter or valve by which the flow of air into the pipe R
may be controlled through the medium of the rod i having a handle k on its
front end.
A fan or other blower may be employed to force air through the pipe N N, in
cases where the chimney draught is not sufficient for the purpose.
The application of this invention in the case of other descriptions of furnaces,
such for instance as a puddling furnace, will be readily understood without need
for further illustration. In the case, however, of a puddling furnace or similar
furnace, it is preferred to carry the heating pipe or flue within the brickwork
surrounding the heating chamber, and not in the chamber itself, but such pipe or
flue may, if desired, be carried within the neck of the furnace, as in such position
the temperature is not so great as in the chamber, and its position there does not
interfere with the operations carried on within the heating chamber.
The application of my invention, also, in the case of working two furnaces
together will be readily understood without special illustration. When this part of
my invention is employed in the case of boiler furnaces, a flue is carried from the
back end of the flue of one of the boilers into position to communicate with the
wedge-shaped space between the bars a a etc. and the front plate F of the furnace
of the other boiler. In such case, if the chimney draught is not sufficient, it may
be supplemented by a fan or other blower placed within the flue communicating
between the flue of one boiler and the furnace of the other boiler, or in other
convenient position. When this arrangement is adopted in the case of the ordinary
construction of furnace, the flue for carrying the hot gases from the one furnace to
the other furnace communicates with the ash-pit of the other furnace, and such
ash-pit is closed in front, but a suitable ventilator may be employed for the
admission of air.
The arrangement of air-heating pipe may be employed in the case of any
construction of furnace having a closed ash-pit.
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 in respect of furnaces is :-
1. A hopper having inclined fire-bars, between the outside of which and a wall
or plate is enclosed a space into which air passes from a tube or flue passing through

page_text: a flue or flues from the furnace, or through a chamber heated by the furnace, or
through the brickwork surrounding such last mentioned flue or flues, or such
chamber, or partly through such last mentioned flue or flues or chamber and partly
through the surrounding brickwork, substantially as and for the purpose herein
described.
2. An air-heating pipe or flue, substantially as described, for delivering heated
air into a closed ash-pit.
3. The means by which the hot gases are passed from the flue or heating chamber
of one furnace through the grate of a second furnace, substantially as herein
described.
4. The inclined hollow fire-bars, formed preferably of wrought iron or steel tubes,
substantially as and for the purpose herein described.
5. The inclined slot, or holes, through the front plate F, substantially as and for
the purpose herein described.
6. The bearer d with an inclined slot or holes therethrough for the purpose of
protecting the lower ends of the fire-bars, substantially as herein described and
shewn by the drawings herewith.
7. A pipe or flue in position for supplying air to the hot gases from the furnace
grate, such pipe or flue being in communication with an air-heating pipe or flue,
substantially as herein described.
8. The pipe R and nozzles g g etc. for the purpose set forth.
9. The combinaton of furnace grate, flue, and air-heating pipe N N, shewn by
the drawings herewith as applied to a steam boiler.
Dated the Thinker fest d... SML 10oc
STEPHEN WATKINS,
Agent for the Applicant.