Improvements in Electric Furnaces.
Year: 1893

page_text: Date of Application, 16th Aug., 1893
Complete Specification Left, 15th May, 1894-Accepted, 16th Aug. 1894
PROVISIONAL SPECIFICATION.
Improvements in Electric Furnaces.
I, FRÉDÉRIC CHAPLET of 15 Rue des Halles, Paris, France, Electrician, do
hereby declare the nature of this invention to be as follows:-
This invention relates to a furnace with movable electrodes and comprises, inter
alia improvements in the form of electric furnace originally employed by M. Moissan
for the preparation of artificial diamonds.
By means of this apparatus the preparation of refractory substances or substances
more or less difficult of fusion, and the preparation of metalloids, metals, or alloys
difficult to fuse, is performed in a manner more economical, efficient and convenient
than has heretofore been practicable.
In the accompanying drawings,
Figs. 1, 2, and 3 are vertical sections of furnaces constructed according to this
invention.
An electric furnace according to this invention comprises a lower part A and an
upper part or cover B. The cover B is hollowed out recessed or domed on its
underside, to obtain a reverberatory effect. The lower part A is also recessed but
more deeply than the cover in the form of a basin whose perimeter corresponds to
that of the upper hollow.
These two recesses form the interior of the furnace.
Movable carbon electrodes C, C between which a larger or smaller electric arc
may be formed, are mounted on suitable carriages C' each penetrating to about
the middle of the interior of the furnace. The carriages C' are mounted on rails
or brackets C³ so that the carbons may be, as desired, easily moved towards or
away from each other, so as to increase or diminish at will the size and the heating
power of the arc.
In the furnace is arranged, a refractory pipe, conduit, or tube D preferably of
carbon of any suitable form, which serves to protect the material to be melted
from contact with the arc and from the surrounding gases.
The tube D may only project into the furnace and have its inner end closed as
in Fig. 3, or it may be provided with removable covers at both ends and extend
completely through the furnace.
In some cases a retort or muffle may take the place of the said tube D, and
more than one such tube or equivalent may be used. The tube D may be placed
at a short distance above or below the arc, or by the side thereof inclined more
or less in such a manner that the solid material which is introduced into its upper
opening and which is to traverse it will slide down slowly whereas the parts of the
material which are melted, and consequently liquid, will flow away rapidly, either
into a crucible outside as in Fig. 2, arranged under the lower end of the pipe,
which may be either permanently open or only when required, or into a basin
arranged at a suitable part of the pipe, forming a reservoir from which the liquid
may be taken from time to time through an opening closed by a suitable cover of
clay or by a luted stopper of charcoal.
Several arcs may be arranged around a single pipe D, or several of these tubes D
may be arranged near one arc or to several arcs.
The upper opening of the tube D is, by preference, slightly larger than the
bore as in Fig. 2 and is or may be in the form of a funnel, to facilitate the intro-
duction and the pushing forward of the material to be melted; it is or may be
provided with a movable cover.

page_text: The refractory material of which the furnace is formed may be Courson stone
or any other suitable limestone, magnesia, silicates difficult of fusion, carbon, or a
combination of these materials.
It will be seen, from the foregoing, that with such a furnace continuity of fusion
is obtained, by means of which with a given furnace and given electrodes and
currents, a larger quantity of molten material can be produced in the same time
more easily, more economically, with a greater degree of purity, than heretofore
and without coming into contact with the arc and the atmosphere with which it is
surrounded.
As stated in place of the pipe D there may be provided a retort, horizontal or
inclined, the closed end of which penetrates into the interior of the furnace, the
other end opening outside to receive in a crucible or boat, the material to be
melted. This form of furnace somewhat resembles a muffle and. is partially
continuous in operation, as the crucibles can be substituted for or take the place of
one another.
Dated this 16th day of August 1802
F. CHAPLET,
By L. W., per F. B.
Improvements in Electrio Furnaces.
I, FRÉDÉRIC CHAPLET, of 15 Rue des Halles, Paris, France, Electrician, 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:-
7.
This invention relates to electric furnaces with movable electrodes and comprises
inter alia improvements in the form of electric furnace employed by M. Moissan
for the preparation of artificial diamonds.
In the accompanying drawings,
Figs. 1 and 2 are vertical sections at right angles to each other, of an electric
furnace constructed according to this. invention.
It comprises a lower part A and an upper part or cover B. These parts are
made of refractory materials and the joint between them is suitably luted. The
cover B is hollowed out, recessed, or domed on its underside; and the lower part A
is also recessed, but more deeply than the cover, in the form of a basin, whose
perimeter corresponds to that of the upper hollow. The recesses in the parts A
and B are made in such a manner as to produce a thoroughly reverberatory effect.
These two recesses form the interior of the furnace.
Movable carbon electrodes C¹ C¹ between which a larger or smaller electric arc
can be formed, are mounted on suitable carriages C*. Each of the electrodes C, C'
normally penetrates to about the middle of the interior of the furnace. The
carriages C are mounted on wheels, which rest on rails or brackets C³, so that
the electrodes may be easily moved towards or away from each other, so as to
increase or diminish, at will, the size and the heating power of the arc.
In the furnace is arranged a tube D, of suitable refractory material (usually
carbon) and of any suitable form, which serves to protect the material to be melted
from contact with the arc and with the surrounding gases.
The tube D is provided with removable covers D* at both ends and extends
completely through the furnace. It may be placed at a short distance above or
below the arc, or by the side thereof and its upper end is somewhat bell-mouthed.
The said tube is inclined more or less according to the nature of the material to be
treated, which it receives through its upper end, in such a manner that the said
material will slide slowly down it and that when the material becomes melted it will

page_text: flow away
into a crucible E through the lower end of the tube D which may be
opened either permanently or only when required.
Fig. 3 represents a furnace also formed of two parts A, B traversed by movable
electrodes C C and provided with a retort or tube D₁ for the reception of the
material to be treated; but in this case the said tube is made in the form of a
retort or muffle D¹, being closed at its lower or inner end, which is situate in the
interior of the furnace. Cups, cupels, or small crucibles containing the material to
be melted can be arranged in the tube D', which may be arranged either in a
horizontal or in an inclined position as shown. This form of furnace is practically
continuous in operation, as the cups, cupels, or small crucibles can be substituted
for, or take the place of one another.
Several pairs of electrodes may be arranged around a single tube D or D', or
several of the tubes D or D¹ may be arranged near to one or to several pairs of
electrodes.
The refractory material of which these furnaces are formed, may be Courson
stone or any other suitable limestone, magnesia, a silicate difficult of fusion,
carbon, or a combination of these materials.
By the arrangements described, instead of being thrown in disorder, or pro-
miscuously, on the hearth of the furnace, the materials to be melted are, on the
contrary, arranged in the tubes D or D' (the former of which also serves to conduct
the materials outside the furnace) and are protected from the action of the internal
gases of the furnace, whilst they are at the same time intensely heated through the
refractory walls of the tubes, by the electric arcs that play between the movable
electrodes.
There are, however, cases, in particular that of materials that pass from the
viscous state only with difficulty, in which, whilst the materials should during
melting be protected as much as possible from contact with the internal gases of
the furnace, they should, when melted, flow into the interior of the furnace and be
protected from the contact of the external air. In such cases I employ a furnace
such as that represented in Fig. 4 or Fig. 5.
Each of these furnaces is made of two parts a, b, which are placed and luted one
on the other and are arranged to be removable from each other by sliding or rolling
in a horizontal direction. The upper part 6 carries pairs of movable electrodes c
and c¹ and a suitably inclined tube or retort d. In the furnace shown in Fig. 4, the
tube d is a single one and is provided at its lower part with an aperture O through
which the melted material flows out. The furnace shown in Fig. 5 is provided
with two tubes d' and arranged at an obtuse angle to each other and having an
aperture O¹ formed at their junction for the running out of the molten material.
Each of the tubes d and d² is adapted to receive the material to be melted at its
upper end.
The lower part of each of the tubes ddd is heated throughout by the arcs of
the several electrodes c c¹ and near each of the apertures O and O' there is
arranged one or more pairs of electrodes the arcs of which are particularly intended
to heat the material when it has become viscous and at the place where it should
become detached from the tube d or tubes d¹ din order to run into the basin or
receptacle e, which may extend over the whole of the hearth of the furnace as
shown in Fig. 5, or only over a portion thereof as shown in Fig 4.
The basin e, in which the molten material is received and in which it is retained
at a high temperature and protected from all immediate contact with the external
air, is, as is shown in the figs., formed in the lower part a of the furnace. The
continuity of the fusion can be easily secured in the furnaces shown in Figs. 4 and 5
by substituting a new lower part a for one that has already been in use, each lower
part being for this purpose made capable of removal from the upper part 6 by being
rolled or slid in a horizontal direction.
It will be seen from the foregoing description, that with any of my improved
furnaces continuity of fusion can be obtained, so that with a given furnace and
given electrodes and currents, a larger quantity of molten material can be produced

page_text: in the given time, and more easily, more economically and with a greater degree of
purity than heretofore, and without the material coming into contact with the arc
and the atmosphere with which it is surrounded.
My improved electric furnaces are suitable for the preparation of refractory
substances of extreme hardness such as those described in the Specification of
another application for Letters Patent filed by me No. 15453 of 1893, as well as
for the preparation or treatment of other substances difficult to fuse.
Having now particularly described and ascertained the nature of the said inveu-
tion and in what manner the same is to be performed I declare that what I
claim is :-
. An electric arc furnace formed of two principal parts A, B, or a 6 of refractory
material, luted together, traversed by movable electrodes C C¹ or cc', and provided
with one or more tubes D D³, d or d³ d³, the arrangement being that the material
to be melted or treated, which is arranged in these tubes, is separated from the
atmosphere that exists in the interior of the furnace, by the refractory wall of
the said tube or tubes either totally, as in the furnaces represented in Figs. 1, 2
and 3 or as in those shown in Figs. 4 and 5, merely until the material arrives
at the apertures or O' in the said tube or tubes that serves for the running
of the said melted material into removable basin e hollowed out of the hearth
of the furnace and near to which aperture one or more electric arcs can be
produced between one or more pairs of electrodes c c¹ as set forth.
11 1
100
Dated
of May 1994.
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.