IMPROVEMENTS IN CRUCIBLE FURNACES
Year: 1884

page_text: I BENJAMIN JOSEPH BARNARD MILLS of the firm of Harris and Mills of
23 Southampton Buildings in the County of Middlesex, Patent Agent do hereby
declare the nature of the said Invention for IMPROVEMENTS IN CRUCIBLE FURNACES
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
The improvements to which the present Invention relates, consist in a heating
stove forming a constituent part of the furnace and in which the charge that is to
be melted in the crucible furnace is previously heated to such a degree, that the
bursting of the crucibles through the considerably higher temperature of the
furnace cannot occur.
The previous heating of the charge takes place upon the lower part of the furnace
which is moveable upon a rail-track and carries the fire grate and the blast
admitting chamber; in order to regulate the admission of the blast and to enable-
the clearing away of the fuel from the grate and the further utilization of the same,
the said bottom part of the furnace is provided with some special improved
contrivances. The improvements for regulating the admission of the blast consist
in a plate arranged beneath the fire grate and turnable from the outside; the
clearing away of the burning fuel from the grate is effected by a grate that can be
removed from the bottom part of the furnace, further by a jacket placed above the
said grate and which can be removed therefrom and finally by some special
contrivances for removing these said parts.
Said improvements are represented in the accompanying, Drawings.
Figure 1 represents a longitudinal section of the heating stove and of the bottom
part of the furnace, arranged below the said heating stove.
Figure 2 is a horizontal sectional view and partially a plan view of one half of
the heating stove.
Figures 3, 4, and 5 represent the improvements relating to the regulation of the
admission of the blast and to the removeable upper parts of the bottom part of the
furnace.
Figure 6 shows the arrangement of one crucible furnace combined with three
heating stoves.
י
Figures 7, 8, 9, 10 and 11 represent auxiliary contrivances forming no part of
the present Invention...

page_text: The heating stove A represented in Figures 1 and 2 serves to obtain a rapid and
regular working of the furnace. Beneath this heating stove is placed the bottom
part of the furnace B Figure 1 into which the charge has previously been
introduced.
The heating stove consists of a cylinder C, lined with hollow cylinders a of some
refractory material and provided with a cap b also lined with some refractory
substance.
In order to draw off the smoke and the gases produced by the combustion of the
fuel the cap b. of the heating stove is provided with a chimney flue-D having an
outer opening c and a regulating damper d.
The cylinder C is enclosed in a jacket, which serves as a guide to the cylinder
whilst the cylinder is lowered upon the bottom part of the furnace.
In order to facilitate the easy lowering of the cylinder together with the chimney
flue, it is suspended upon chains e running over pulleys ƒ and carrying at their
opposite ends counterweights g; by means of these chains and counterweights the
cylinder C is so balanced that its raising and lowering can be effected very easily,
without needing any considerable exertion of power.
As soon as the fuel is placed upon the grate h and ignited the cylinder C is let
down and the charge heated to incandescence. The blast is introduced by
pipes i. i.
When the charge has been sufficiently heated the cylinder C is again raised and
the bottom part B of the furnace is conveyed directly to the melting furnace F
Figure 3. The previous heating of each charge requires about three times as much
time as the melting process, the continuous working of each melting furnace
requires a continuous working of three heating stoves.
Such an arrangement is represented in Figure 6 where a melting furnace F is
placed upon a turntable and communicates by means of rail tracks j with three
heating stoves A; other rail tracks / lead from the turntable to the places G where
the charge is introduced and where the melted metal is discharged.
In order to regulate the admission of the blast and consequently the beat
developed in the furnace, a perforated plate n is arranged beneath the fire grate h,
the perforated apertures of which plate correspond with the openings of the grate.
This perforated plate n is fastened to the turnable supporting arms m, fitted upon
a spindle which can be turned by means of a lever o. By thus turning the
plate the openings p of the grate h can be shut more or less, according to
whether it is wanted to let in more air through the tuyeres q and through the
central blast piper than through the apertures p.
In order to enable a rapid clearing and cooling of the bottom part of the furnace,
the jacket 8, its lining t and fire grate h are so constructed that they can be
removed from the bottom part B, by means of a hoist of any desired construction.
The removal of the jacket a is effected by means of a yoke, bow or hoop H,
Figure 4 and the removal of the fire grate h is effected by means of a horizontal
beam I Figure 5 connected with two vertical bars u in the bottom ends of which
are turning two trunnions v. These trunnions are rivetted in the fire grate h and
made capable of turning in the bottom ends of the bars u, so as to facilitate the
tilting of the grate and the clearing off of the burning fuel and of the ashes.
The burning fuel taken from the furnace when the melting process has been
terminated, may be employed for feeding annealing furnaces with a continuous
working or for some other similar purposes.
The melted metal is emptied from the furnace into a large vessel, Figures 7
and 8, the size of which is such that it can hold the contents of a whole charge.
This vessel, Figure 7, consists of a reservoir K made of thick metal plates and
provided with a lining w of some refractory material; on both sides of the vessel
in places corresponding to its centre of gravity, it is provided with two trunnions,
by means of which it is suspended from the crane suspension x.
The top of the vessel is provided in front with a spout y, Figure 8, and behind
with an incision y¹ serving for the removal of the slag. In order to prevent the

page_text: outward radiation of the heat, said vessel Figure 7 is enclosed in an isolating
jacket z; the space between the reservoir K and the jacket z being filled with
refractory sand or with some other heat resisting material. The vessel can be
covered by a lid L, Figure 9, fitting in the inwardly bent projecting flange z¹
fastened to the top rim of the vessel; the lid L is provided with an aperture for
introducing the blast pipe.
In order to convey the said vessel, Figure 7, to the crane hoist, the vessel is
placed in a box filled with refractory sand or some other isolating material, so as to
prevent the outward radiation of heat, and this box is placed upon a truck or
car M. For manufacturing small castings or figured ingots or soft cored steel
goods, the melted metal is transfused from vessel, Figure 7, into transfusing vessels
of a smaller size. These portable transfusing vessels N, Figure 11, are provided
each with two spouts 22, and with a groove 23, for the tongs. Figure 10 represents
a lid serving to cover the said transfusing vessels and is provided with a hopper.
It is evident that these transfusing vessels may also be previously heated; they
can be filled either from the large vessel; Figure 7, or directly from the crucibles.
Having now particularly described and ascertained the nature of the said
Invention; and in what manner the same is to be performed, I declare that what
I claim is:
.
First: A heating stove for previous heating of charges destined for cast steel
crucible furnaces, the said heating stove consisting of a cylinder C moveable in an
up and down direction inside a jacket E, and lined inside with hollow refractory
cylinders and provided with a cap also made of some heat resisting material and
carrying the chimney flue having an outer aperture c, and a regulating damper d;
said cylinder C, with the above named parts. connected to it being suspended upon
chains e running over pulleys and carrying at their opposite ends counterweights g
by means of which the cylinder, together with the parts connected to it, can be so
balanced, as to be easily raised or lowered above the bottom part of the furnace,
substantially as shown and described.
Second: In order to prevent the bursting of the crucibles through the high
temperature of the furnace and to accelerate the melting process, the previous
heating of the furnace charge by means of a heating stove substantially as
described.
Third: In order to either accelerate or check the process of combustion in
crucible furnaces, the arrangement of a blast regulating plate n turnable by means
of lever o and spindle and provided with openings corresponding with the
openings p, of grate h; the turning of said plate n producing a complete or partial
shutting of the openings p whereby the blast air is forced to find its way more
through the tuyeres q, and through the central blast pipe r, than through the said
openings p of the grate, substantially as specified.
Fourth In order to enable a rapid clearing and cooling of the furnace, the
arrangement of a jackets, that can be taken off together with its lining, and of
bow H, serving to lift the said jacket, further the arrangement of grate h that can
also be taken off, and of the particular contrivance I and u connected with
trunnions fastened to the grate and permitting the tilting of the same,
substantially as herein shown and described.
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