IMPROVEMENTS IN FURNACES
Year: 1878

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
FURNACES." A communication from abroad by Franz Joseph Böhm, of
Donitz, near Karlsbad, Bohemia, in the Empire of Austria.
Sealed the 1st November 1878, and dated the 31st May 1878.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 31st May 1878.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. 'IMPROVEMENTS IN FURNACES." A communication from abroad by
Franz Joseph Böhm, of Donitz, near Karlsbad, Bohemia, in the Empire of Austria.
This Invention relates to the use in furnaces of an improved fire-box or grate
capable of being withdrawn from the furnace for the purpose of enabling the opera-
tion of stoking and feeding the fire to be performed with greater facility and clean-
liness than heretofore.
In carrying out this Invention, a cast-iron front plate is employed secured to the
wall or to any other convenient part of the furnace by means of wrought-iron clamps.
In an opening provided in the middle of the plate are formed two recesses for the
reception of two cast-iron rails which are secured to the wall by means of pro-
jections cast upon them, and the front ends of which project for a suitable distance
beyond and in the front of the cast-iron plate forming the front of the furnace. Upon
these rails is supported a cast-iron grate or fire-box of suitable form and dimensions,
which is capable of sliding upon the said rails through the opening in the cast-iron
plate herein-before referred to.
The front of the fire-box is made to lap over the edges of the opening in the front
of the furnace, so as to close it effectually when pushed back, and is provided with
a small door for the purpose of enabling the fire to be inspected.
In the case of large and heavy constructions, two or more small cast-iron rollers
are provided between the rails, the upper portion of their circumferences being level

page_text: with the upper surfaces of the rails, and upon which the fire-box is enabled to travel
with greater facility when it is withdrawn from or pushed back into the furnace.
The sides of the fire-box may, if required, be protected from melting or burning
by lining them with refractory materials, such as the dust of fire-bricks, glass pots,
or seggars, according to the degree of heat to which they are exposed.
A suitable number of fire-bars are provided within the fire-box of the required
length, underneath which is fitted a sliding damper for the purpose of enabling the
supply of air to the fire to be controlled as required. The air is admitted through
a ventilator consisting of a certain number of holes in the front plate of the furnace
underneath the damper, and which admit of being wholly or partially closed by a
sliding cover.
An opening is provided in the front plate below these air holes for the reception
of an ash pan which is capable of being drawn out when required.
The charging of the fire-box is effected by causing it to travel upon the rails (a
handle being provided in order to facilitate this operation) and drawing it out of
the furnace as far as may be required in order to enable the fuel to be conveniently
placed in it and ignited. When this has been effected, the fire-box is pushed back
into the furnace, and the damper drawn out as far as requisite in order to admit a
sufficient supply of oxygen which passes into the fire through the air holes or venti-
lator herein-before referred to.
In order to prevent any inconvenience from the smoke when the fire-box is drawn
out of the furnace, a sheet metal cover is provided behind the fire-box, and connected
thereto by a pin, whereby the draft of air is automatically cut off each time that the
fire-box is drawn out.
The upper surface of the damper as well as the fire-box itself may be covered
or fitted with refractory materials as herein-before described for the purpose of
protecting these parts from injury when intense heat is required in the furnace.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the 2nd
November 1878.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN FURNACES." A communication from abroad by
Franz Joseph Böhm, of Donitz, near Karlsbad, Bohemia, in the Empire of Austria.
The said Invention relates to the use in furnaces of an improved fire-box or
grate capable of being withdrawn or partially withdrawn from the furnace for
the purpose of enabling the operation of stoking and feeding the fire to be per-
formed with greater facility and cleanliness than heretofore.
And in order that the said Invention may be fully understood, I shall now
proceed more particularly to describe the same, and for that purpose shall refer
to the several Figures on the annexed Sheets of Drawings, the same letters of
reference indicating corresponding parts in all the Figures.
Figure 1 of the accompanying Drawings represents a longitudinal sectional eleva-
tion of a furnace provided with an improved fire-box or grate, according to the
said Invention; Figure 2 is a transverse section; and Figure 3 is a front eleva-
tion of the same, both corresponding to Figure 1.
Figure 4 is a side elevation of the fire-box shown detached from the furnace with
one of the rails herein-after referred to.
In the arrangement illustrated in the Drawing the furnace is constructed with a
cast-iron front plate a secured to the wall or to any other convenient part of
the furnace by means of four wrought-iron clamps h. In an opening provided
in the middle of the plate a are formed two recesses for the reception of two
cast-iron rails e, secured to the wall by means of four projections cast upon them,
the front ends of which rails project for a suitable distance beyond and in front
of the cast-iron plate forming the front of the furnace. Upon these rails is supported a
cast-iron grate or fire-box b of suitable form and dimensions, which is capable of sliding
upon the said rails through an opening in the cast-iron plate a; projections n are
formed upon the rails e, and corresponding projections m are provided on the sides
of the fire-box b (see Figures 2 and 4) which when the fire-box is drawn forwards
come in contact with the first-mentioned projections, the latter acting as stops, and
preventing it from being accidentally drawn out further than is required.
The front of the fire-box is made to overlap the edges of the opening in
the front of the surface, so as to close it effectually when pushed back, and
is provided with a small door b', in order to enable the fire to be inspected.
In the case of large and heavy constructions, two or more small cast-iron rollers
are provided between the rails, the upper portion of their circumferences being level
with the upper surfaces of the rails, and upon which the fire-box is enabled to
travel with greater facility when it is drawn out from or pushed back into the
furnace.
The sides of the fire-box may, if required, be protected from melting or
burning by providing them with a lining o composed of refractory materials, such for
example as the dust of fire-bricks, glass pots, or seggars, according to the degree
of heat to which they are exposed.
A suitable number of fire-bars c of the requisite length are provided within the
fire-box b, underneath which fire-bars is fitted a sliding damper & for the purpose
of enabling the supply of air and the fire to be controlled as required. The air is
introduced through a ventilator consisting of a certain number of poles in the
front plate a underneath the damper d, and which admit of being wholly or partially
closed by a sliding cover l.
An opening is provided in the front plate a below these air holes for the reception
of an ash pan g which is capable of being drawn out as often as necessary.
When it is required to charge the fire-box, the damper d is closed and the fire-box
is drawn out by the aid of a handle i, as far as necessary, in order to enable the fuel

page_text: to be conveniently placed in it and ignited. When this has been effected the fire-
box is pushed back into the furnace and the damper d is drawn out as far as requisite
in order to admit a sufficient supply of oxygen which is introduced through the air
holes 7.
In order to prevent any inconvenience from the sınoke when the fire-box is
drawn out of the furnace a sheet metal cover f is provided behind the fire-box and
connected thereto by a pin k, whereby the draft of air is automatically cut off each
time that the fire-box is drawn forwards.
-
The upper surface of the damper d like the fire-box may be covered or fitted with
refractory materials o' for the purpose of protecting this part from injury when
intense heat is required in the furnace.
The said Invention is applicable to furnaces of every description.
Having now described and particularly ascertained the nature of the said In-
vention, and the manner in which the same is or may be used or carried into effect,
I would observe in conclusion, that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the herein-before in part recited
Letters Patent is, the combination in a furnace of a fire-box so arranged as to be
capable of travelling on rails with a regulating damper underneath, and parallel with
such fire-box in conjunction with an adjustable ventilator in the front of the
furnace for the admission of air, all substantially in the manner and for the purpose
herein-before described, and as illustrated in the accompanying Drawings.
In witness whereof, I, the said John Henry Johnson, have to this my Specifi-
cation set my hand and seal, the Twenty-eighth day of October, One thousand
-eight.hundred and seventy-eight.