Improvements in and relating to Electric Furnaces.
Year: 1893

page_text: Date of Application, 8th July, 1893
Complete Specification Left, 29th Mar., 1394-Accepted, 5th May, 1894
PROVISIONAL SPECIFICATION.
[Communicated from abroad by ADAM CHARLES GIRARD, of 7, Rue du Bellay,
Paris, France, Chemist, and ERNEST AUGUSTE GEORGES STREET, of
39, Rue Joubert, Paris, France, Engineer.]
Improvements in and relating to Electric Furnaces.
I, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent Agents,
45 Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention to be as follows:-
This invention relates to electric furnaces.
As applied to the treatment of solid materials which are conductors of electricity
and in the form of rods, bars, or wires of any transverse sections, this improved
electric furnace comprises an exterior casing preferably metallic which may or may
not contain a suitable block of refractory or other material formed in one or more
parts. The said block when such is used has formed in its interior a cavity which
constitutes the heating chamber proper, and in which terminates a radial channel
adapted to receive a carbon rod that forms one electrode of the arc. Another
channel extends right through the block and into this latter channel the bar, rod or
the like to be subjected to the treatment is introduced. To this bar or rod is
imparted by rotating friction rollers or other means a translatory motion which
causes it to traverse the heating chamber at a speed which is regulated in accordance
with its mass and the temperature to which it is to be heated.
The electrical circuit is completed through the moving bar or rod to be heated
and the carbon electrode before mentioned. The arc which is formed between these
two electrodes remains stationary in the heating chamber notwithstanding the
translatory motion of the bar or rod, and impinges on the moving bar or rod along
a continuous line, heating the bar or rod to a very high temperature.
It will be readily understood that the speed of the moving bar or rod controls
the mean temperature which each part of the same will attain.
The current is conducted to the moving rod or bar by means of a suitable sliding
contact or brush.
The length of the are between the carbon and the moving bar or rod may be kept
constant by means of an arrangement such as is customarily employed for this
purpose in arc-lamps.
The operation of the above described apparatus is continuous, because the bars,
rods or the like to be treated may be caused to succeed each other without
interruption.
In case the heating is to be effected in an appropriate atmosphere of gas with
exclusion of the ordinary atmosphere, the bar or rod is passed through stuffing-
boxes on entering and leaving the furnace. The carbon electrode also passes
through a stuffing-box. Inlet and outlet orifices for the gas are provided, the same
having suitable stop taps, and, if desired, a pressure gauge to indicate the pressure
of gas in the furnace.
The moving bar or rod, before entering and after leaving the furnace proper,
travels in suitable tubes or chambers filled with the special gas whereby it is
prepared for the action of the furnace and is cooled before passing into the outer
atmosphere.

page_text: It will be understood that when the refractory block is dispensed with the furnace
in other respects is practically the same as above described.
I in some instances subject the bar or rod to be heated to the action of more than
one electric arc; I may also cause the bar or rod to rotate so that the arc or arcs
will touch the whole circumference thereof; I may moreover change the position
or angle of the carbon or carbons relatively to the rod or bar to be heated as may
be desired; may also modify the inlets and outlets for the gas, and cool the
metallic parts of the furnace by circulating water around such parts, or by other
means.
In case it is desirable to treat pulverulent materials which are or are not suscep-
tible of being fused, such materials are enclosed (according to one construction) in
a tube of suitable section and formed of a material adapted to withstand the
temperature which the mass has to bear, and which may be closed at both ends.
This tube is moved through the furnace in the manner above described with
reference to the treatment of rods and bars, thus passing the pulverulent material
gradually through the furnace.
In lieu of moving with its receptacle, the material under treatment may be moved
through its tube or receptacle which latter then remains stationary.
In this modification the general arrangement of the furnace remains the same,
but the heating chamber proper cousists preferably of a carbon tube or crucible of
any suitable form which serves at the same time as a receptacle and an electrode
for the arc.
The heating is effected by means of two arcs in series or by means of several
groups of two arcs in series. The first arc leaps from the first carbon electrode to
the carbon tube or crucible forming the heating chamber and the second arc leaps
from the said crucible to the second carbon electrode. The material to be treated
is introduced through the upper part of the furnace which is closed by a suitable
cover, and is withdrawn from the Tower part of the furnace. Said cover is sealed
by a hydraulic or other joint to effectually close the upper part of the furnace.
Special arrangements may be employed for the withdrawal and introduction of the
materials, according as the said materials, after their passage into the furnace, are
in the solid, liquid or gaseous state. Lastly, suitable gas may be introduced or
circulated through the furnace according to the treatment which the materials
subjected to the action of the furnace are to undergo.
The gas may be introduced by means of a suitable inlet tube in the upper part
of the furnace, and can leave through the outlet orifice for the materials. The size
of this outlet may be suitably regulated to cause the materials to remain in the
furnace for any desired length of time.
The gas may in some cases be introduced and discharged through the carbons
themselves or at any point which may be deemed suitable.
In case the materials are such that they will be fused during their passage through
the heating-chamber proper or crucible, I employ a furnace constructed with a
hearth to receive the fused materials and having a casting orifice or outlet so
arranged that notwithstanding said outlet the special gas which may be used in the
operation may be retained in the furnace as long as desired.
The furnaces are provided with stuffing-boxes, spy glasses, and gas inlet and
outlet pipes.
.
For
In a further modification of this invention I provide for distributing in an equable
manner the action of the electric arc over the materials under treatment.
achieving this result I cause the arc to rotate in the interior of the furnace by
producing in the furnace a suitable magnetic field. As applied for example to the
furnace above described for the treatment of bars, rods and the like, I replace the
carbon electrode described with reference thereto by one carbon or two or more
carbons of suitable shape placed in the interior of the furnace. The carbon or eacb
carbon when there are more than one, is pierced with a transverse hole of suitable
shape, through which the rod or bar to be treated passes, and the arc is formed
between said rod or bar and the pierced carbon or carbons. The arcs may be

page_text: struck by drawing the pierced carbons outwardly until they are brought into
contact with the transverse bar or rod, and then pushing them back to their normal
position; or the arc may be struck in any other suitable manner. This arc is an
element of current. produce a magnetic field whose lines of force are
perpendicular to this element of current, by surrounding the tubes or chambers
which contain the special gas with a suitable spiral winding of wire which will be
traversed either by the same current as that which feeds the arc or by a portion of
this current, or by a separate current. The effect of the current in the spiral
winding is to produce a magnetic field in which the lines of force are parallel to
the rod or bar to be treated and thus perpendicular to the arc. That part of the
metallic casing of the furnace between the windings should in this instance consist
of non-magnetic metal. Under the action of the magnetic field thus constituted,
the arc is caused to turn in a plane perpendicular to the axis of the rod or bar
under treatment, and will touch said rod or bar at all the points of its circumference.
The speed of rotation of the arc will depend upon the intensity of the current
which traverses the latter and on the intensity of the magnetic field induced in the
interior of the furnace by the exterior windings.
The arcs from the carbons to the rod or bar under treatment may be in series or
in parallel. The conductors of the current and the insulation are made in con-
formity with the strength of current used.
It will be obvious that a rotating arc can be used in the types of furnaces
described with reference to the treatment of pulverulent materials. In this case
the carbon tube or crucible is surrounded by one or more carbon discs which are
concentric therewith, and insulated from one another, and between which and the
said tube arcs are caused to form. This arc or these arcs is or are subjected to the
action of a magnetic field as hereinbefore described.
The revolving are can also be applied to other types of electric furnaces than
those above described.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Electric Furnaces.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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 :-
This invention relates to electric furnaces.
In the following description of the methods of carrying out the invention,
reference will be had to the accompanying drawings, in which
Figure 1 is an elevation partly sectional of one form of improved electric furnace
constructed according to the said invention.
Figure 2 is an end view of the same.
Figures 3 and 4 are vertical sections of modified forms of the electric furnace.
Figure 5 is an elevation partly sectional shewing a further modification, and
Figure 6 is a detail view hereinafter described.
Like letters denote similar parts throughout the drawings.
As applied to the treatment of solid materials which are conductors of electricity
and in the form of rods, bars, or wires of any transverse sections, the improved
electric furnace, as shewn for example in Figures 1 and 2, comprises an exterior
casing preferably metallic which encloses a suitable block a of refractory material
which is a bad conductor of heat, formed in one or more parts. The said block

page_text: has formed in its interior a cavity c which constitutes the heating chamber proper,
and in which terminates a radial channel adapted to receive a carbon rod d that
forms one electrode of the arc. Another channel extends right through the block
and into this latter channel the bar, rod or the like e to be subjected to the treat-
ment is introduced. To this bar or rod is imparted by rotating friction rollers for
other means a translatory motion which causes it to traverse the heating chamber c
at a speed which is regulated in accordance with its mass and the temperature to
which it is to be heated.
The electrical circuit is completed through the moving bar or rod e to be heated
and the carbon electrode d. The arc which is formed between these two electrodes
remains stationary in the heating chamber notwithstanding the translatory motion
of the bar or rod e and impinges on the moving bar or rod along a continuous line,
heating the bar or rod to a very high temperature.
It will be readily understood that the speed of the moving bar or rod e controls
the mean temperature which each part of the same will attain.
The current is conducted to the moving rod or bar by means of a suitable sliding
contact or brush o.
The length of the arc between the carbon d and the moving bar or rod e may be
kept constant by means of an arrangement such as is customarily employed for
this purpose in arc-lamps.
In some instances I dispense with the block a and line the casing of the furnace
with a suitable refractory material which is a bad conductor of heat. For example
I sometimes employ a lining of retort carbon or agglomerated carbon, such lining
being suitably insulated from the electrodes. In some. instances I have neither
block nor lining.
The operation of the above described apparatus is continuous, because the bars,
rods or the like to be treated may be caused to succeed each other without inter-
ruption.
In case the heating is to be effected in an appropriate atmosphere of gas
with exclusion of the ordinary atmosphere, the bar or rod is passed through
stuffing-boxes g and h on entering and leaving the furnace. The carbon electrode
also passes through a stuffing box k. Inlet and outlet orifices for the gas are
provided at and m, the same having suitable stop taps, and, if desired, a pressure
gauge, the tube for which is shewn at n to indicate the pressure of gas in the
furnace.
The moving bar or rod, before entering and after leaving the furnace proper,
travels in suitable tubes or chambers p filled with the special gas whereby it is
prepared for the action of the furnace and is cooled before passing into the outer
atmosphere.
It will be understood that when the refractory block is dispensed with the
furnace in other respects is practically the same as above described.
The tubes or chambers containing the special gas are in some instances
electrically insulated from the metallic material of the furnace.
The carbon electrode may also be insulated if desired.
I in some instances subject the bar or rod e to be heated to the action of more
than one electric arc; I may also cause the bar or rod to rotate so that the arc or
arcs will touch the whole circumference thereof; I may moreover change the
position or angle of the carbon or carbons d relatively to the rod or bar to be
heated or rotate the said carbon or carbons round the said rod or bar e, as may be
desired; I may also modify the inlets and outlets for the gas, and cool the
metallic parts of the furnace by circulating water around such parts, or by other
means.
In case it is desirable to treat pulverulent materials which are or are not
susceptible of being fused, such materials are enclosed (according to one construc-
tion) in a tube of suitable section and formed of a material adapted to withstand
the temperature which the mass has to bear, and which may be closed at both ends.
This tube is moved through the furnace in the manner above described with

page_text: reference to the treatment of rods and bars, thus passing the pulverulent material
gradually through the furnace.
In lieu of moving with its receptacle the material under treatment may be moved
through its tube or receptacle which latter then remains stationary.
In this modification as shewn for example in Figure 3 the general arrangement
of the furnace remains the same, but the heating chamber proper consists preferably
of a carbon tube or crucible r of any suitable form which serves at the same time
as a receptacle and an electrode for the arc.
The heating is effected by means of two arcs in series or by means of several
groups of two arcs in series. The first arc leaps from the first carbon electrode s
to the carbon tube or crucible r forming the heating chamber and the second arc
leaps from the said crucible to the second carbon electrode u. The material t to
be treated is introduced through the upper part of the furnace which is closed by a
suitable cover v, and is withdrawn from the lower part of the furnace. Said cover
is sealed by a hydraulic or other joint to effectually close the upper part of the
furnace. Special arrangements may be employed for the withdrawal and intro-
duction of the materials, according as the said materials, after their passage into
the furnace, are in the solid, liquid or gaseous state. Lastly, suitable gas may be
introduced or circulated through the furnace according to the treatment which the
materials subjected to the action of the furnace are to undergo.
The gas may be introduced by means of a suitable inlet tube w in the upper
part of the furnace, and can leave through the outlet orifice y for the materials.
The size of this outlet may be suitably regulated to cause the materials to remain
in the furnace for any desired length of time.
The gas may in some cases be introduced and discharged through the carbons
themselves or at any point which may be deemed suitable.
In case the materials are such that they will be fused during their passage
through the heating-chamber proper or crucible r, I employ a furnace, constructed
as shewn in Figure 4 for example with a hearth made of suitable material to receive
the fused materials and having a casting orifice or outlet 2 so arranged that
notwithstanding said outlet the special gas which may be used in the operation may
be retained in the furnace as long as desired.
The furnaces are provided with stuffing-boxes, spy glasses, and gas inlet and
outlet pipes.
In a further modification of this invention I provide for distributing in an
equable manner the action of the electric arc over the materials under treatment.
For achieving this result I cause the arc to rotate in the interior of the furnace by
producing in the furnace a suitable magnetic field. As applied for example to the
furnace above described with reference to Figures 1 and 2 for the treatment of
bars, rods and the like, I replace the carbon electrode d by one carbon or two or
more carbons S, S, see Figures 5 and 6, of suitable shape placed in the interior of
the furnace. The carbon or each carbon when there are more than one, and
which may be of the section shewn in Figure 6, is pierced with a transverse
hole of suitable shape, through which the rod or bar e to be treated passes, and
the arc is formed between said rod or bar and the pierced carbon or carbons.
The arcs may be struck by drawing the pierced carbons S, S outwardly until
they are brought into contact with the transverse bar or rod e, and then pushing
them back to their normal position; or the arc may be struck in any other
suitable manner. This arc is an element of current. I produce a magnetic field
whose lines of force are perpendicular to this element of current, by surrounding
the tubes or chambers which contain the special gas with a suitable spiral
winding of wire which will be traversed either by the same current as that which
feeds the arc, or by a portion of this current, or by a separate current. The effect
of the current in the spiral winding is to produce a magnetic field in which the
lines of force are parallel to the rod or bar to be treated and thus perpendicular to
the arc.
That part of the metallic casing of the furnace between the windings

page_text: should in this instance consist of non-magnetic metal. By the action of the
magnetic field thus constituted, the arc is caused to turn in a plane perpendicular
to the axis of the rod or bar e under treatment, and will touch said rod or bar at
all the points of its circumference.
The speed or rotation of the arc will depend upon the intensity of the current
which traverses the latter and on the intensity of the magnetic field induced in the
interior of the furnace by the exterior windings.
The arcs from the carbons to the rod or bar under treatment may be in series or
in parallel. The conductors of the current and the insulation are made in
conformity with the strength of current used.
It will be obvious that a rotating arc can be used in the types of furnaces
described with reference to Figures 3 and 4 for treating pulverulent materials.
In this case the carbon tube or crucible r is surrounded by one or more
carbon discs which are concentric therewith, and insulated from one another,
and between which and the said tube arcs are caused to form. This arc or
these arcs, is or are subjected to the action of a magnetic field as hereinbefore
described.
The revolving are can also be applied to other types of electric heating
apparatus than those above described.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondents, I declare that what I claim is :-
1. For heating solid materials in the form of rods, bars, and the like an electric
furnace (with or without means for the supply or outlet of gases) comprising
a block, made of refractory material which is a bad conductor of heat, such block
having a beating chamber in which terminates a carbon or in which terminate
several carbons serving as one electrode of the arc, the other electrode being the
bar or rod to be heated which is passed through a channel and heating chamber
substantially as described.
2. The modification of my invention wherein I provide for heating granular or
pulverulent materials in a tubular cylinder which is continuously passed through
the heating chamber with or without means for the supply or outlet of gases,
substantially as described.
3. In any electrical furnace for heating pulverulent or granular materials the
provision of a carbon casing for separating the said materials to be heated from
direct contact with the electric arc.
4. The modification of my invention wherein I provide for the heating of
granular or pulverulent materials in a carbon casing through which the material is
fed and which at the same time forms the common electrode for two arcs in series,
or several groups of arcs in series, substantially as described.
5. The furnace provided with a casting orifice at the lower part of the heating
chamber, substantially as described and shewn in Figure 4.
6. In an electric furnace the provision of means for causing the generation of
one or more arcs successively over all the parts of the surface of the piece to be
heated, substantially as, and for the purpose, described.
7. In combination with electric heating apparatus, the provision of means for
producing a magnetic field arranged to cause rotation of the arc or arcs, which
supply and maintain the required heat.
8. In an electric furnace, the employment of two arcs in series or of several
groups of two arcs in series, the material or the receptacle containing the material
to be heated serving as an electrode common to all, substantially as described.
9. In an electric furnace the provision of an electrode or electrodes pierced
with a hole concentric to the material or to the receptacle containing the material
under treatment, in combination with means for producing a magnetic field,
substantially as, and for the purpose, described.

page_text: 10. The electrical furnaces shown in Figures 1 and 2, Figure 3, Figure 4, and
Figures 5 and 6 respectively, substantially as described.
Dated this 28th day of March 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.