Improvements in Electric Furnaces.
Year: 1897

page_text: Improvements in Electric Furnaces.
I, RAMÓN CHAVARRIA CONTARDO, of 5, Rue de la Plaine Perdue, Sèvres, Seine,
France, Doctor of Law, do hereby declare tlie nature of this invention to be as
follows:-
The object of my invention is a continuous electric furnace, so contrived that
the whole of the heat generated by one or more voltaic arcs as well as that arising
from the rich combustible gases, produced by the reduction of the oxidised mineral
under treatment can be utilised.
In order that the nature of my invention may be understood, I shall first briefly
describe a simple form of my furnace and thereafter I shall describo certain com-
pound forms.
A simple furnace constructed according to my invention comprises essentially
a reduction chamber for the mineral, an electric heating chamber, and a collecting
chamber for the metal.
The sides of my furnace are constructed in a special manner, in this sense that
the construction comprises two distinct elements: the one being ordinary fire-
resisting or refractory brickwork or masonry, and the other, extra-refractory
material, for example plumbago, or a material kept cool by means of a circulating
cooling fluid; these two kinds of material being judiciously employed, according
to their particular qualities. The refractory masoury being incapable of support-
ing the great heat produced by the arc, all the parts exposed to this are of extra-
refractory material, or are kept cool by a circulating fluid, or are formed of plumbago.
This last mentioned substance, however, having the disadvantage of not supporting
direct contact with the air of combustion, all the parts exposed to this contact are
of refractory masonry. The description given below, will make clear the way in
which I carry out this part of my invention, which is of the greatest importance
as it provides me with the only means, hitherto known, for combining the action
of the voltaic are and that of atmospheric air in one and the same furnace.
The electric heating chamber is formed of the side walls of the furnace and by
a cover or cap, sloping on either side in the manner of a roof, and intended for
protecting the electrodes against the descending charge, from the chamber above
and without impeding the action of the intense heat in that direction. The said
cover or cap may of course be of any other suitable shape, for example, a semi-
cylinder. The carbon electrodes of dimensions proportioned to the necessary cur-
rents, enter or penetrate into the furnace by holes, formed in the side walls and
lined or covered with some material which is a non-conductor of electricity, or by
tuyeres for the circulation of water, properly isolated, in such a manner that any
entry of air at these points is impossible.
The lower ends of the cap stop short at a little distance from a double or divided

page_text: bottom, in order to retain the reduced ores, which are ready for fusing, whilst
allowing a free passage for the fused metal which accumulates in the collecting
chamber, heated by the are placed directly above it. Between these lower ends
themselves, and between the lower ends and the side walls, are vertical passages by
which the reduced ore descends to the bottom plates, where it is exposed to the
direct heat of the arc.
The collecting chamber is furnished with a tap-hole and conduit as well as with
an orifice for the continuous or intermittent discharge of the slag, cinder, etc.
The chamber constructed of refractory masoury, is of a height suited to the
nature of the ore to be reduced. It is provided with holes for the admission of
air, formed at different levels, and with a feeding throat. The air entering the
chamber, by the action of a natural or artificial draught, puts the carbonic oxide
produced by the reduction into a state of combustion; the heat thus produced serv-
ing to reduce the agglomeration of carbon and ore, or even to effect the reduction,
by the gas successively transformed into carbonic acid and carbonic oxide, as iu
the blast furnace, if the ore and fuel be charged in alternate layers, in the ordinary
manner.
This chamber is supported by a lower metallic base which permits of its being
raised, when it is desired, for instance, to examine or repair the interior of the
furnace or to change the cap belonging to the heating chamber.
The compound furnace, is distinguished from the simple one by the fact that,
in place of a single electric heating chamber, it comprises a series of chambers in
juxtaposition, the number of which may be varied according to the particular case
to which the system is applied and the product to be obtained.
For purposes of manufacture, this furnace is more economical as regards the
setting up and gives a better return.
The ore, agglomerated with the mass in a state of fusion or charged in alternate
layers, as in the ordinary blast furnace, is introduced into the orifice by one or
more charging apertures or throats, closed by covers. The gases are drawn off
by one or more apertures suitably placed for the purpose. The collecting chamber
extends throughout the whole length of the furnace and may thus be of consider-
able capacity.
In certain cases it may be useful or advantageous to arrange the voltaic hearth
or hearths otherwise than in the manner just mentioned, that is to say, to place
the arcs in relation to one another in a different manner to that indicated, which
is one of simple juxtaposition.
Thus, if it be necessary or be preferred to have a heating centre of circular form,
this arrangement can be adopted. The two carbons of each arc are there arranged
parallel to each other, as for example in the Jablokof candle, and radially in rela-
tion to the centre of the furnace which is circular. The converging electrodes,
which may be of any suitable number, are protected by a cover or cap having,
for example, the form of an arch, suitably supported, and concentric to the side
wall of the furnace with which it is connected by means of walls or septa.
In a modification, the hearth or heating centre is still more compact. The arch
has no central orifico and thus becomes a cupola under which is the hearth or heat-
ing chamber.
From the foregoing it will be seen that I do not intend to restrict myself to the
special forms of construction and arrangement described above or to the precise
details of construction and arrangement mentioned. I reserve to myself on the
contrary the right of applying to my continuous electric furnaces any modifica-
tion as regards construction, and not going beyond the scope of my invention,
which experience and practice may suggest to me.

page_text: Improvements in Electric Furnaces.
I, RAMON CHAVARRIA CONTARDO, of 5, Rue de la Plaine Perduc, Sèvres, Seine,
France, Doctor of Law, do hereby declare the nature of this invention, and in
what manner the same is to be performed, to be particularly described and ascer
tained in and by the following statement:-
-
The object of my invention is a continuous electric furnace, so contrived that
the whole of the heat generated by one or more voltaic arcs as well as that arising
from the rich combustible gases, produced by the reduction of the oxidised mineral
under treatment can be utilized.
In order that the nature of my invention may be readily understood I have
appended hereto a sheet of drawings in which simply by way of demonstration, I
show several forms of furnaces embodying, the essential features of my invention.
In these drawings,
Figure 1 is a vertical section, through the line OD in Figure 3, of a simple
furnace, having a single heating chamber and a double or duplex arc.
Figure 2 is a vertical section of this furnace through the line E-F in Figure 1.
Figure 3 is a horizontal section through the line A-B in Figure 1.
Figures 4 and 5 are respectively a vertical section through the broken line G-H
in Figure 5, and a horizontal section through the broken line I-J in Figure 4
of a compound furnace, that is to say with a number of arcs.
Figure 6 is a horizontal half section of a compound furnace, in which the collec-
tion of voltaic arcs constitutes a central hearth or heating centre of great intensity.
Figure 7 is a vertical section on the broken line K-L of Figure 6.
Figure 8 is a horizontal section of a half of a compound furnace in which the
arrangement of arcs constitutes an intensely heating centre as will be hereinafter
described.
In all the figures of the drawings, the same reference lotters indicate the same
parts.
A simple furnace constructed according to my invention (Figures 1, 2 and 3)
comprises essentially a reduction chamber for the mineral, an electric heating
chamber, and a collecting chamber for the metal.
The sides of my furnace are constructed in a special manner, in the sense that
the construction comprises two distinct elements; the one being ordinary fire-
resisting or refractory brick-work or masonry, and the other, extra refractory
material, for example plumbago, or a material kept cool by means of a circulating
cooling fluid; these two kinds of material being judiciously employed, according
to their particular qualities. The refractory masonry being incapable of support-
ing the great heat produced by the arc, all the parts exposed to this are of extra
refractory material, or are kept cool by a circulating fluid, or are formed of plum-
bago. This lust mentioned substance however, having the disadvantage of not
supporting direct contact with the air of combustion, all the parts exposed to this
contact are of refractory masonry. The following description in conjunction with
the drawings will make clear the way in which I carry out this part of my inven-
tion, which is of great importance. as it provides me with a means of combining
the action of the voltaic are and that of atinospheric air in one and the same
furnace.
The electric heating chamber a is formed of the side walls of the furnace and by
a cover or cap b,. sloping on either side in the manner of a roof, and intended for
protecting the electrodes e against the descending charge from the chamber above d
and without impeding the action of the inteuse heat in that direction. The said
cover or cap may of course be of any other suitable shape, for examplo a semi-
cylinder. The carbon electrodes c, of dimensions proportioned to the necessary

page_text: currents, enter or penetrate into the furnace by holes, formed in the side walls and
lined or covered with some material which is a non-conductor of electricity, or sur-
rounded by tubes for the circulation of water, and are properly isolated in such a
manner that any entry of air at these points is impossible.
The lower, ends of 'the cap 6 stop short at a little distance from a double or
divided bottom, e, e, in order to retain the reduced ores, which are ready for
fusing, whilst allowing a 'free passage for the fused metal which accumulates in
the collecting chamber f heated by the are placed directly above it. Between these
lower ends themselves and between the lower ends and the side walls are vertical
passages 9, 9, by which the reduced ore descends to the bottom plates e, e where it
is exposed to the direct heat of the arc.
The collecting chamber is furnished with a tap hole and conduit hi, as well
as with an orifice for the continuous or intermittent discharge of the slag,
oinder, etc.
The chamber constructed of refractory masonry, is of a height suited to the
nature of the ore to be reduced. It is provided with holes k, for the admission
of air, formed at different levels, and with a feeding throat. The air entering the
chamber, by the action of a natural or artificial draught, puts the carbonic oxide
produced by the reduction into a state of combustion; the heat thus produced serv-
ing to reduce the agglomeration of carbon and ore (comprising also the necessary
fluxes), or even to effect the reduction, by the gas successively transformed into
carbonic acid and carbonic oxide, as in the blast furnace, if the ore and fuel be
charged in alternate layers in the ordinary manner.
This chamber is supported by a lower metallic buse which permits of its being
raised, when it is desired, for instance to examine or repair the interior of the
furnace or to change the cap belonging to the heating chamber.
The parts constructed of ordinary refractory masonry are distinguishable in the
drawings by simple diagonal lines; and those composed of plumbago or extra-
refractory material, or material acted upon by a circulating cooling fluid, by cross
diagonals. It will thus at once be seen how I distribute these different substances
so as to obtain the result specified above.
The compound furnace, represented in Figures 4 and 5, is distinguished from the
simple one by the fact that instead of a single electric heating chamber, it com-
prises a series of chambers in juxtaposition, the number of which may be varied
according to the particular case to which the system is applied and the product to
be obtained.
For purposes of manufacture, this furnace is more economical as regards the
setting up and gives a better return.
The ore, agglomerated with the mass in a state of fusion or charged in alternate
layers, as in the ordinary blast furnace, is introduced into the orifice by one or
more charging apertures or throats closed by covers m, m. The gases are drawn
off by one or more apertures n, n, suitably placed for the purpose. The collecting
chamber extends throughout the whole length of the furnace and may thus be of
considerable capacity.
In certain cases it may be useful or advantageous to arrange the voltaic hearth
or hearths otherwise than in the manner just mentioned, that is to say to place the
ares in relation to one another in a different manner to that indicated, which is
one of simple juxtaposition.
Thus, if it be necessary or be preferred to have a heating centre of circular form,
the arrangement illustrated in Figures 6 and 7 can be adopted. The two carbous
of each arc are there arranged parallel to one another as for example in the Jab-
lokof candle and radially in relation to the centre of the furnace which is circular.
The converging electrodes, which may be of any suitable number, are protected by
a cover or cap having, for example, the form of an arch suitably supported, and
concentric to the side wall of the furnace with which it is connected by means of
walls or sopta.

page_text: In the modification shown in Figure 8 the hearth or heating centre is still more
compact than in the previously mentioned form. The semi-torus has no central
orifice and thus becomes a cupola under which is the hearth or heating chamber.
I do not intend to restrict myself to the precise details of construction and
Arrangement illustrated in the drawings.
Having now particularly described and ascertained the naturo of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. The new or improved continuous electric furnace substantially as set forth.
2. The simple form of furnace substantially as set forth with reference to
Figures 1, 2 and 3.
3. The compound furnace substantially as set forth with reference to Figures 4
nud 5.
4. The compound furnace substantially as set forth with reference to Figures 6
und 7.
5. The modified form of compound furnace substantially as set forth with refer-
ence to Figure 8.
6. In a furnace as set forth, the employment of distinct materials (ordinary
fire-resisting or refractory masonry and material of an extra fire resisting or refrac-
tory nature, or cooled by a circulating cooling fluid), for the purposes set forth.
Dated this 8th day of November 1897.