Improvements in and connected with Electric Furnaces.
Year: 1897

page_text: Date of Application, 16th Feb., 1897-Accepted, 17th Apr., 1897
Improvements in and connected with Electric Furnaces.
I, FRANCIS JARVIS PATTEN of 40 Wall Street, New York, in the County and
State of New York, United States of America, Electrical Engineer, do hereby
leclare 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
tatement:-
My invention consists in a system of electric furnace construction in which an
electric arc, being established between electrodes, is made to move by magnetic
influence from one point to another so as to arrive at and affect material that
it would not reach if it remained practically steady at one point or in a fixed
position.
The said invention is illustrated by Figures 1, 2, 3 and 4 of the accompanying
drawings in which Figures 1 and 2 represent the application of the principle and
Figures 3 and 4 shew forms of furnace construction in which a different electric
circuit system is used of which I will call that shewn by Figure 4 the preferred
form.
It is a well known physical fact that an electric arc will move out of a magnetic
field if free to do so and in a definite direction determined by the direction of the
lines of force of the field viewed from north to south as positive and the direction
of current flow in the arc. Thus in Figure 1, where C¹ represents an upright slab
of carbon placed at arcing distance from the horizontal carbon slab C2, which I will
designate as the electrodes of the furnace, and N S are the poles of an electro-
magnet so placed that the arc between the electrodes is normally in the field of the
magnet of which the lines of force will be assumed to flow from N to S then the
arc between the carbons will assume a position dependent upon the direction of
current flow and the lines of force.
Thus, if the lines of force have the direction N to S, and the current flows from
the upper to the lower carbon, then the arc will assume the position A', to the
left corner of the upright carbon slab. Now, if either the current should change
its direction, or direction of the magnetic field should reverse, then in either case,
the are would pass over to the right hand corner of the upper carbon slab assuming
the position A, Figure 1.
In these physical conditions therefore lies the possibility of moving the arc to
and fro across the edge of the upper carbon slab. It is only necessary to let the
arc be produced by a slowly alternating current and place the electrodes in a strong
magnetic field as indicated in Figure 1, then the arc will move across the lower
edge of the upper electrode from one side to the other at each alternation of current.
It makes no difference in effect whether the current between the electrodes is
alternated or whether the magnetic field be reversed in direction, the result will be
the same and the arc will traverse back and forth from one side to the other with
each reversal of current or of magnetism. It is upon these different lines for
accomplishing the same result that my two forms of furnace construction shewn on
the drawings, are based.
Figure 2 shews an arrangement of upright parallel electrodes placed in juxta-
position with the carbon base or slab forming the other electrode.
The current
between the upper series of electrodes and the lower is indicated as reversing or
alternating whilst the magnetic field is constant. The several arcs in this case will

page_text: traverse back and forth from side to side of the upper carbon with each alternation
of current, and if material were passed between the upper and lower electrodes, it
would be attacked by the arcs A A, in rapid succession as they vibrated to and
fro over the passing material.
Figure 3 shews in cross sectional elevation, a furnace constructed on the plan
of using an alternating current between electrodes and a fixed magnetic field. The
lower electrode C has a slanting upper surface so that the material passing thereon
will roll, slide or flow down its surface from right to left, while the arcs between
the several upper electrodes and the lower one are traversing back and forth from
one side of the magnetic field N S to the other. A practical sheet of electric flame
is thus established through which the material must pass. B B, Figure 3, represents,
in cross section, a surrounding and supporting brick structure. F, is an iron slab
on which the lower carbon rests and to which one terminal of the working circuit
is attached, the plus-minus sign indicating an alternating or reversing current.
CC are the upper electrodes, all connected with the other working circuit terminal,
and NS are the poles of an electric magnet of fixed polarity.
The material to be fused is supplied through the hopper O, and is drawn off in
the liquid or molten form through the outlet tube T.
Figure 4 illustrates what I have already designated my preferred form of furnace.
In this, the electrode or working current is constant in direction, and the magnetic
field is slowly reversed.
It will of course be understood that the current should not reverse too rapidly
in the system shewn by Figure 3, but should preferably have a comparatively slow
period or rate, preferably much slower than the period rate of ordinary alternating
currents such as are used in lighting circuits. It is also a realy inference that
if the current between electrodes be direct and the magnetic field be reversed in
order to move the ares, then this magnetic reversal should also be comparatively
slow, otherwise excessive heating and loss of energy would be the consequence.
In the furnace illustrated by Figure 4, these features are all provided for. A direct
current dynamo D, supplies a continuous current through the furnace, which is of
the same general construction as that already described with reference to Figure 3.
A shunt circuit taken from the brushes of the dynamo D, is led to the two plates
of conducting material K' K' of the liquid current reverser shewn at the bottom of
the figure. This is a reverser of special form adapted to reverse currents of
considerable strength without sparking or rupture of circuit.
The circular part T represents in plan a tub or vessel at the center of which
there is a spindle carrying an arm at the extremities of which there are two other
conductor plates K 3 and K 4. The spindle is driven by the motor M, and the
plates K3 K4 consequently pass the fixed plates every half revolution. The
rotating plates are respectively connected with insulated sliding ring contacts R' R'
upon which the brushes H₁ H2 bear, and as a result of the rotation a slowly
reversing alternating current is delivered to the circuit which includes the magnet
coils of S N N S. It follows that the magnetism is correspondingly reversed and
that the arcs between the electrodes C and C are traversed back and forth.
Thus, there is a direct current system throughout, with slowly reversing
magnetisın.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is :-
1. The method of operating an electric furnace which consists in passing the
material to be operated upon between electrodes, subjecting the arc to the influence
of a magnetic field, whose lines of force are substantially transverse to the direction
of the arc, and reversing or alternating either the current in the are or the magnetic
field whereby the arc is reciprocated transversely to the path of the material,
substantially as hereinbefore described.
2. The method of operating an electric furnace which consists in passing the

page_text: material to be operated on between electrodes, subjecting the arc to the influence
of a magnetic field whose lines of force are substantially transverse to the direction
of the arc, passing a direct current through the electrodes and reciprocating the
arc by reversing or alternating the magnetic field, substantially as herein before
described.
3. In an electric furnace, a lower electrode and an upper plate electrode, an
electromagnet having its poles so arranged that its lines of force pass through the
arc and are normal to the upper electrode, and means for reversing or alternating
either the arc producing current or the magnet exciting current, whereby the arc
is caused to reciprocate, substantially as herein before described.
4. In an electric furnace, electrodes consisting of a block and above it at arcing
distance a plate, an electromagnet having its poles so arranged that the lines of
force pass through the arc normal to the upper electrode, means for passing a direct
current through the electrodes, and means for reversing or alternating the magnet
exciting circuit, substantially as herein before described.
5. In an electric furnace, the combination with a lower electrode of a plate
electrode having its lower edge at arcing distance above the lower electrode, means
for feeding material between the electrodes, means for creating a magnetic field
having its lines of force passing through the arcing space, and means for
alternating or reversing said field whereby the arc is reciprocated, substantially as
hereinbefore described.
6. In an electric furnace having for a lower electrode an inclined block or slab
over which the material is fed, and for its upper electrode a series of plates having
their lower edges transverse to the movement of the said material, means for passing
a direct current through said electrodes, and means for creating a reversing
magnetic field of force transverse to the upper electrodes whereby the arcs are
caused to reciprocate, substantially as herein before described.
arc between
7. The method of imparting a reciprocating movement to an
electrodes, which consists in causing the arc to traverse a magnetic field in which
the lines of force are substantially transverse to the direction of the arc and reversing
or alternating either the arc producing current or the magnetic field, substantially
as hereinbefore described.
arc between
8. The method of imparting a reciprocating movement to an
electrodes which consists in causing the arc to traverse a fixed magnetic field
and reversing or alternating the arc producing current, substantially as hereinbefore
described.
9. The combination with means for producing a magnetic field, of electrodes
arranged to produce an arc across said field, and means for reversing or alternating
either the arc producing circuit or the magnetic field whereby the arc between the
electrodes will be reciprocated, substantially as hereinbefore described.
1007
Dated this 16
15th day February
1847
W. E. HEYS & SON,
Agents for the Applicant.