IMPROVEMENTS IN FURNACES
Year: 1879

page_text: LETTERS PATENT to Edward Brook, of Bradford, in the County of York,
Engineer, for the Invention of "IMPROVEMENTS IN FURNACES."
PROVISIONAL SPECIFICATION left by the said Edward Brook at the Office
of the Commissioners of Patents on the 16th July 1879.
EDWARD BROOK, of Bradford, in the County of York, Engineer. "IMPROVEMENTS
IN FURNACES."
"
This Invention relates to furnaces for the combustion of fuel, applicable to the
manufacture of iron, chemicals, glass, the production of gas, heating of steam boilers,
and such like purposes; and particularly to furnaces of the class wherein a round,
square, or rectangular chamber of considerable depth, built of firebrick, with solid
hearth and no grate bars, has at the top a "retort or receptacle into which the
fuel is fed, and which is open at the bottom, around, or partly around, which the
escaping gases and flame circulate on their way to the outlet, the ashes and fire
resting on the hearth, and one or more doorways or openings being provided in the
walls for removal of ashes; also openings or tuyeres above the floor for admitting
air to the fire, and the whole being cased outside with iron, or bound together by
stays and rods.
According to my Invention, I apply to such furnaces an improved "step-grate,"
and construct them with an improved arrangement of bottom or lower part, us
hereinafter described.
At
In carrying out my Invention, I build the furnaces as previously described, square
or rectangular in plan, but I recess the back and part of the two end walls somewhat
on the inside at the bottom, and provide a hollow casting to carry the front wall,
which casting I arrange at some distance above the floor, thus leaving an opening
or doorway underneath, through which the ashes and clinkers are removed.
the bottom of the furnace I provide a floor of iron plates, and underneath this floor
an airtight chamber into which the necessary air is forced by means of one or more
steam jet blowers, and from whence it is led by passages up the sides of the door-
way, into the hollow casting over the doorway. This hollow casting over the
doorway, supporting the front wall, is perforated along its inner face for passing a
portion of the air and steam into the fire at this point; and it is also perforated
Driss zi

page_text: along its underside for passing the remainder of the air and steam into passages
formed in an iron door closing the aforesaid doorway when the furnace is at work.
The passages-in-this-iron-door-lead-downwards-a-little-distance-to-the-outer-edge-of-
This
a casting, acting the part of what is commonly known as a "step-grate."
casting or "step-grate" instead of being formed of one flat plate or bar, as is
customary, is composed of two plates a little distance apart connected together by
ribs, thus forming passages therein, through which the greater part of the air and
steam coming down the passages in the door is passed into the fire. This " step-
grate is considerably broader than usual, and is protected where necessary by
refractory material; it rests on supports at each end of the furnace about halfway
up the doorway, thus leaving a space above and underneath it, through, which
spaces the ashes and clinkers are easy of access and removal. The front part of the
fire being held up by this "step grate" gives ready access to the ashes, etcætera,
collecting at the back part of the furnace.
i
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Brook in the Great Seal Patent Office on the 16th January
1880.
EDWARD BROOK, of Bradford, in the County of York, Engineer.
IN FURNACES."
"IMPROVEMENTS
This Invention relates to furnaces for the combustion of fuel, applicable to the
manufacture of iron, chemicals, glass, the production of gas, heating of steam boilers,
and such like purposes, and particularly to furnaces of the class wherein, as usually
constructed, a round, square, or rectangular chamber of considerable depth, built of
firebrick, with solid hearth and no gratebars, has at the top a "retort" or receptacle
into which the fuel is fed, and which is open at the bottom, around or partly
around which the escaping gases and flame circulate on their way to the outlet, the
ashes and fire resting on the hearth, and one or more doorways or openings being
provided in the walls for removal of ashes; also openings or tuyeres above the
floor for admitting air to the fire, and the whole being cased outside with iron, or
bound together by stays and rods.
According to my Invention I apply to such furnaces an improved "step grate,"
and construct them with an improved arrangement of bottom or lower part, as
hereinafter described.
In carrying out my Invention, I build the furnaces as previously described,
square or rectangular in plan, but I recess the back and part of the two end walls
somewhat on the inside at the bottom, and provide a hollow casting to carry the
front wall, which casting I arrange at some distance above the floor, thus leaving
an opening or doorway underneath through which the ashes and clinkers are
removed. At the bottom of the furnace I provide a floor of iron plates, and under-
neath this floor an airtight chamber into which the necessary air is forced by means
L

page_text: of one or more steam jet blowers, and from whence it is led by passages up the
sides of the doorway into the hollow casting over the doorway. This hollow casting
over the doorway supporting the front wall is perforated along its inner face for
passing a portion of the air and steam into the fire at this point; and it is also
perforated along its underside for passing the remainder of the air and steam into
passages formed in an iron door closing the aforesaid doorway when the furnace is
at work. The passages in this iron door lead downwards a little distance to the
outer edge of a casting, acting the part of what is commonly known as a "step-
grate." This casting or "step-grate" instead of being formed of one flat plate or
bar as is customary, is composed of two plates a little distance apart, connected
together by ribs, thus forming passages therein through which the greater part of
the air and steam, coming down the passages in the door, is passed into the fire.
This "step grate" is considerably broader than usual, and is protected where
necessary by refractory material; it rests on supports at each end of the furnace
about half way up the doorway, thus leaving a space above and underneath it,
through which spaces the ashes and clinkers are easy of access and removal. The
front part of the fire being held up by this "step grate" gives ready access to the
ashes, etcetera, collecting at the back part of the furnace.
DESCRIPTION OF THE DRAWINGS.
"
Fig. 1 is a front elevation with part in section on the line y, y, in Fig. 2, and
Fig. 2 a transverse sectional elevation, shewing a furnace according to my Invention.
Fig. 3 is a part horizontal section in the line x, x, of Fig. 2. The same letters are
used in all the views to denote like parts. R is the "retort' or receptacle open at
the bottom. It is formed by building an arch R2 across at a little distance from
the back wall R³. This retort is kept filled, or nearly so, with fuel fed through the
opening (or openings) A closed by a plug (or plugs) P lined with fire clay, and
each fitting into a hole in an iron plate laid on the top. B is the solid hearth of
iron plates ribbed underneath, upon which part of the ashes and clinkers rest. 0
is the outlet for the flame and gas. D is the door closing the opening for with-
drawal of ashes and clinkers. This door has plates secured to it so as to form
passages for conveying air or air and steam to the "step grate" and lower part of
the fire. S is the "step grate" resting on supports at each end of the furnace, and
protected by refractory materials as shewn; its principal object is to support the
front portion of the fire, thus giving great facility for access to and withdrawal of
ashes and clinker that collect at the back part. In practice it is desirable the
space underneath the step grate should be not less than about seven inches deep.
H is the hollow casting which is arranged to support the front wall over the
doorway and convey air to the various apertures for admission to the fire, and has
stoking holes E cast with it to admit of breaking up the fire, the holes being
closed by small moveable plugs; c, c, are small perforations having an aggregate
area slightly larger than the openings closed by the small plugs; through these
openings c, c, air passes into the fire, thus preventing flame from issuing when the
small plugs are withdrawn from the stoking holes. There are other perforations
(marked F) in this casting to admit of the insertion of bars when necessary to
support the fire whilst withdrawing ashes and clinkers from the top of the "step
grate"; G, G, are castings for conveying the air and steam from the steam jet
blowers up the sides of the doorway to the hollow casting H; J is the air tight
chamber containing the steam jet blowers; K, K, are the recesses in the back and
part of the two end walls for preventing clinker adhering to the walls at these
parts. The openings L, L', where the air or air and steam issue into the fire should
not extend to the end walls within about nine inches.
The furnace is shewn in the Drawings as a gas producer cased with iron, which
is carried up some distance above the top, to retain the coal when it is thrown
thereon, and to carry the shaft and lovers for working the plug (or plugs) P, but in
some cases where the furnace can be placed close to the object to be heated, and

page_text: where the chimney draught is capable of drawing sufficient air through the fire
without the aid of the steam jet blowers, the air tight chamber J and the steam jet
blowers may be omitted...
In applying the furnace to the various purposes enumerated, it is to be placed as
close as convenient to the object to be .heated, and the outlet O connected thereto
by a firebrick flue, and the-gas burnt at the point where the heat is required on
_any_of_the well known systems.
In some applications, where the furnace can be placed close to the object to be
-heated; as for instance when-applied to a large puddling furnace or to a steam boiler
with two flues, I provide two outlets for the gas and flame.
.
Having thus described the nature of the said Invention, and in what manner the
same is to be carried into practical effect, I wish it to be understood that I do not
limit myself to the precise form and detail, as shewn on the accompanying Drawings,
but what I consider to be novel and original, and therefore claim as the Invention
secured to me under the Letters Patent herein before in part recited is :-
1. The application and use in furnaces such as herein before referred to of the
improved step grate, constructed, arranged and operating substantially as herein-
before described and shewn on the accompanying Drawings.
2. The application and use in furnaces such as hereinbefore referred to of the
improved hollow casting (H) having stoking and air holes and passages, the whole
constructed, arranged and operating substantially as herein before described and
shewn on the accompanying Drawings for the purposes specified.
3. The combined arrangement of apparatus whereby air or air and steam is or
are caused to pass through a hollow casting (H) formed with stoking holes (E), and
supporting the front wall over the doorway; and thence to the interior of the
furnace, partly in a direct manner through openings L, and partly through passages
in a door (D) and step grate (S), all substantially as hereinabove described and
illustrated.
4. The combination of parts constituting the improved furnace constructed,
arranged and operating substantially as shewn in and described with reference to
the accompanying Drawings.
In witness whereof, I, the said Edward Brook, have hereunto set my hand
and seal, this Sixth day of January, in the year of our Lord One thousand
eight hundred and eighty.
EDWARD BROOK. (L.S.)