Improvements in and relating to Electric Furnaces.
Year: 1893

page_text: Date of Application, 4th Apr., 1893
Complete Specification Left, 3rd Jan., 1894-Accepted, 3rd Feb., 1894
PROVISIONAL SPECIFICATION.
Improvements in and relating to Electric Furnaces.
We, RUDOLF URBANITZKY, Engineer, and AUGUST FELLNER, Chemist, both
of 15 Gesellenhausgasse, Linz, in the Empire of Austria, do hereby declare the
nature of this invention to be as follows:-
Our invention relates to electric furnaces.
The improved furnace is specially useful for melting iron ores for the manu-
facture of steel, and for reducing manganese, aluminium oxide and other metallic
oxides by the aid of the electric arc.
The said furnace has the form of a cupola furnace, is provided with a basic lining
similar to that of a Bessemer converter, and possesses a positive electrode consisting
of several parts and conducted into the melting chamber from the side, while the
bottom of the furnace shaft consists of a taper carbon body forming the negative
electrode and pressed into the bottom opening of the furnace shaft after the manner
of a key-stone.
In carrying our invention into practice we construct a furnace having a shaft
built in the form of a cupola furnace, its lowest part which surrounds the melting
zone being provided with a basic lining which as in Bessemer converters consists
of burnt dolomite, magnesite or magnesia, this material being mixed with tar free
from water to form a plastic mass which is pressed into shape and then burnt.
This lining is a non-conductor of electricity.
The bottom of the shaft thus made is formed of a taper body consisting of hard
carbon and resting upon a copper plate which carries a socket-shaped projection
for joining the negative lead. This lead is insulated and protected by a chamotte
pipe. The said copper plate is forced by chamotte wedges against the bottom of -
the furnace, and the carbon body is forced into the bottom opening after the
manner of a key-stone, thereby making a tight joint.
The chamotte wedges serve at the same time for insulating the copper plate and
the carbon body from the iron furnace frame upon which the wedges bear.
The positive electrode preferably consists of four parts, each of which is formed
of carbon plates which for the purpose of obtaining a continuous connection are
provided at one end with a dove-tail groove and at the other end with a corre-
sponding tongue. The groove and tongue are again dove-tailed in the direction of
the width of the carbon plates so that when the several plates are connected with
each other a carbon plate which has almost burnt away will still have a small
portion fixed to the following plate and will be held by the same."
The carbon plates connected to form electrodes are introduced edgeways into the
melting chamber through narrow oblique slots in the furnace shaft.
A heavy current is conducted to the electrodes by means of lateral brushes, the
regulation or maintenance of the arc and the re-formation of the same being
effected by displacement of the positive electrodes in their guides. The regulation
takes place by means of feed rolls provided with insulated hand wheels and
pressed by springs against the carbon plates, whilst for the re-formation of the
arc insulated handles are provided so as to permit of a rapid upward and downward
movement.
Each of the positive electrodes is connected by a lead with the main conductor
extending to the source of electricity.
As the furnace shaft may be completely filled with the ores to be reduced and
the ores themselves are put in the furnace in a divided state, the melting or

page_text: reducing zone is entirely protected from cooling, while the ore to be reduced in
turn is preliminarily well heated.
The positive electrodes having a sharp edge pointed by the combustion of the
same easily penetrate into the pulverized ore and being placed edgeways are
sufficiently strong to resist fracture.
The molten metal produced collects below the positive electrodes when the
discharge aperture is closed, for which reason the said electrodes, in order to
maintain the arc if they do not burn away rapidly enough, are slowly drawn
upwards, which is effected by turning the feed rolls hereinbefore mentioned.
When a sufficient quantity of molten metal has collected it is run off, whereupon
the positive electrodes are lowered again to permit of the re-formation of the arc.
In order to repair the furnace and replace the carbon body which forms the
negative electrode the chamotte wedges are removed so that the bottom of the
furnace shaft becomes free.
To economize the hard carbon, pulverized charcoal which will combine with the
nascent oxygen may be mixed with the ore.
When manufacturing steel it is advantageous to first produce pure iron in the
described furnace, spiegeleisen being then added to the same until the desired
quantity of carbon is obtained in the steel.
Dated this 4th day of April 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in and relating to Electric Furnaces.
We, RUDOLF URBANITZKY, Engineer, and AUGUST FELLNER, Chemist, both
of 15 Gesellenhausgasse, Linz, in the Empire of Austria, 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 :-
Our invention relates to electric furnaces.
The improved furnace is specially useful for melting iron ores for the manu-
facture of steel, and for reducing manganese, aluminium oxide and other metallic
oxides by the aid of the electric arc.
The said furnace has the form of a cupola furnace, is provided with a basic lining
similar to that of a Bessemer converter, and possesses a positive electrode con-
sisting of several parts and conducted into the melting chamber from the side,
while the bottom of the furnace shaft consists of a taper carbon body forming the
negative electrode and pressed into the bottom opening of the furnace shaft after
the manner of a key-stone.
In the accompanying drawing
Figure 1 represents a vertical section of the improved furnace on the line x-x of
Figure 2 and
Figure 2 shows an horizontal section of the furnace, the positive electrodes being
represented in elevation.
In carrying our invention into practice we construct a furnace having a shaft a
built in the form of a cupola furnace, its lowest part which surrounds the melting
zone b being provided with a basic lining b¹ which, as in Bessemer converters,
consists of burnt dolomite, magnesite or magnesia, which material is mixed with tar
free from water to form a plastic mass which is pressed into shape and then burnt.
This lining is a non-conductor of electricity.
The bottom of the shaft thus made is formed of a taper body c consisting of hard
carbon and resting upon a copper plate c¹ which carries a socket-shaped projection d
for joining the negative lead e. This lead is insulated and protected by a chamotte

page_text: pipe f. The said copper plate c¹ is forced by chamotte wedges g against the bottom
of the furnace, and the carbon body c is forced into the bottom opening after the
manner of a key-stone, thereby making a tight joint.
The chamotte wedges 9 serve at the same time for insulating the copper plate
and the carbon body from the iron furnace-frame upon which the wedges bear.
The positive electrode consists of four parts, each of which is formed of carbon
plates which for the purpose of obtaining a continuous connection are provided at
one end with a dove-tail groove and at the other end with a corresponding tongue.
The groove and tongue are again dove-tailed in the direction of the width of the
carbon plates so that when the several plates are connected with each other at ga
carbon plate which has almost burnt away will still have a small portion fixed to.
the following plate and will be held by the same.
The carbon plates / connected to form electrodes are introduced edgeways from
the four sides into the melting chamber through narrow oblique slots in the furnace
shaft.
A heavy current is conducted to the electrodes by means of lateral brushes h, the
regulation or maintenance of the arc and the re-formation of the same being
effected by displacement of the positive electrodes in their guides p. The regulation
takes place by means of feed rolls i provided with insulated hand wheels i¹ and
pressed by springs against the carbon plates, whilst for the re-formation of the arc
insulated handles o are provided so as to permit of a rapid upward and downward
movement.
Each of the positive electrodes is connected by a lead e¹ with the main conductor
extending to the source of electricity.
As the furnace shaft a may be completely filled with the ores to be reduced and
the ores themselves are put in the furnace in a divided state, the melting or
reducing zone is entirely protected from cooling, while the ore to be reduced in
turn is preliminarily well heated.
The positive electrodes having a sharp edge pointed by the combustion of the
same easily penetrate into the pulverized ore and being placed edgeways are
sufficiently strong to resist fracture.
Experience has shown that the upper (positive) electrodes are liable to stick
fast when the direction of the current passes continually from the positive
electrodes to the lower (negative) electrode.
In order to remedy this defect the ore forming the electrolyte must be worked
not only from above downwards but from all sides.
For this purpose the electric current is caused to circulate alternately between
the upper electrodes while the lower electrode is cut out, which can be easily
effected by the aid of a simple switch of any desired construction.
If therefore the four upper electrodes are designated by 1, 2, 3, 4, and the lower
electrode by 5, the following directions of the electric current are obtained, which
may be changed automatically or if necessary also by hand by means of the
switch.

page_text: upwards, which is effected by turning the feed rolls i hereinbefore mentioned.
When a sufficient quantity of molten metal has collected it is run off, whereupon
the positive electrodes are lowered again to permit of the re-formation of the arc.
'In order to repair the furnace and replace the carbon body c which forms the
negative electrode the chamotte wedges are removed so that the bottom of the
furnace shaft becomes free.
"
To economise-the hard carbon, pulverized charcoal which will combine with the
nascent oxygen may be mixed with the ore.
When manufacturing steel it is advantageous to first produce pure iron in the
described furnace, spiegeleisen being then added to the same until the desired
quantity of carbon is obtained in the steel.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
:-
First. An electric melting and reducing furnace, characterized by a furnace
shaft à built in the form of a cupola furnace and provided with a basic lining 1
through which the positive electrode divided into several parts and formed of
connected carbon plates is introduced from the side, whilst the bottom of the
furnace shaft consists of a carbon body c resting upon a metal plate c² and forming
the negative electrode, which body is pressed into the bottom opening for the
purpose of tightly closing the furnace shaft by chamotte wedges g, the current
circulating through a switch between the positive electrodes and the negative
electrode and, when cutting out the latter, alternately between the positive
electrodes.
Second. The device for displacing and adjusting the positive electrode, con-
sisting of the feed rolls i, adapted to be turned by means of insulated hand wheels i¹
and pressed by spring power against the carbon plates I, and of the insulated
handle d.
1004
HASELTINE, LAKE & Co.
45, Southampton Buildings, London, W.C., Agents for the Applicants.