Improvements in and relating to Electric Furnaces.
Year: 1897

page_text: Date of Application, 26th Jan., 1897-Accepted, 3rd Apr., 1897
COMPLETE SPECIFICATION.
Improvements in and relating to Electric Furnaces.
We, JOHN JOYCE and JAMES ALBERT DEUTHER, Gentlemen, citizens of the United
States of America, both of 114 Purchase Street, in the City of Boston, County of
Suffolk and State of Massachusetts, United States of America, do hereby declare the
ature 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 improveinents in electric furnaces for the manufacture of
calcium carbide and for the reduction of refractory and other metallic compounds, and
ts main object is to facilitate the bringing of the material to be treated directly within
the influence of the electric are formed between two separated electrodes, and through
which the electric current passes.
In electric furnaces, the heat generated between two separated electrodes, is
sufficiently intense within the field of the arc formed between said electrodes for
reduction while outside of the influence of the arc the heat is not sufficient for such.
purpose.
For electric furnaces to be economical and practical, the heat incident upon the
formation of the arc should continuously act upon the material to be treated, and said
material should be introduced or brought directly within the influence of the arc, and
further, when such material has been properly affected by the heat incident upon the
formation of the arc, new material should be supplied for treatment and no time
should be lost in introducing the proper amount of new material required.
To illustrate In the process of making calcium carbide in electric furnaces,-this
compound when pure, is composed of metallic calcium and carbon, the metallic calcium
required being obtained preferably from oxide of calcium, and the carbon from coke..
Now, in order to bring about the chemical formation of calcium carbide from said
materials, the heat of the arc is necessary, and while it may be of very high temperature
at the seat of the arc, yet the temperature a few inches from the seat of the arc is not
high enough to produce the product required. This lower temperature, however, at a
few inches from the seat of said arc is sufficient to produce combustion of the carbon
mixed with the oxide of calcium, and probably volatilize the lime, and before this
so called, burnt out, mixture of oxide of calcium can again be utilized or properly
treated by the arc to produce calcium carbide, additional carbon must be added to
take the place of the carbon burnt out, consequently, to avoid the action of burning.
out the carbon, as above described, it is necessary that the material to be treated should
be introduced or fed directly within the influence of the arc, so as to be acted upon in
a comparatively short time."
As is well known in the practical application of the heat incident upon the formation
of the electric arc in the treatment of certain materials, especially refractory compounds,
in electric furnaces, difficulty is experienced in bringing the materials or compounds
to be so treated in said electric furnaces, directly and at stated and determined periods
of time within the sphere of the influence of the electric arc to be properly acted
upon by said electric arc. The sphere of influence of the electric are in the reduction.
of certain alkaline earths, may be defined as where the heat consequent upon the
formation of the electric arc is of sufficiently high temperature to bring about a
reduction of the alkaline earths or other compounds under treatment.
Now it is the purpose and object of our invention to facilitate the bringing of
compounds under treatment in the electric furnace within the sphere of influence of
the arc.

page_text: the accompanying drawings, which illustrate a construction embodying our
invention―
Figure 1 is a vertical cross, section. through the electric furnace, and showing the
opposite electrodes in full lines.
Figure 2 is a similar view, but showing in full lines the lower electrode moved
toward the right, and also showing in dotted lines, the lower electrode moved toward
the left.
Figure 3 is a detail plan view hereinafter described.
The electric furnace A is constructed of fireproof material A', and located in the
bottom of the furnace is the electrode B of conducting material, and connected to one
pole of an electric generator by a suitable wire B¹, and preferably but not necessarily,
of larger diameter than the upper electrode (which is connected to the other pole
of the electric generator by a suitable wire C'. The upper electrode C is suspended
above the electrode B by means of a rod C2, which is provided with two forked
arms secured by suitable nuts to the upper part of the electrode C.. The
rod C² extends upwardly through the cross beam D supported by the side beams D₁,
and the upper end of the rod C projects through the cross bar C³, and suitable
nuts hold said rod C+ connected to the cross bar C. Through the opposite end
of the cross bar C the lifting screw C', working in the nut (8 is arranged, and
its lower end works in the socket C9 on said cross beam D, and by means of said
lifting screw C7 the upper electrode C can be raised and lowered by the mechanism
above described. To the top of the electrode C is firmly secured a rectangular
receptacle E, provided on opposite sides of the electrode C with the ports E' and E².
Within the receptacle E are two movable bottomless boxes F and G connected
together by the cross bar H, and in the normal position of the parts said boxes are
in the position shown in Figure 1 between the ports E and E².
The bottom electrode B is mounted on a suitable casting B2 provided with rollers B³
to facilitate the movement of said lower electrode along the bottom plate A². Said
casting B2 is provided on one side with a socket B in which is held a ball B³ on the
inner end of the shaft B having a worm gear throughout the greater part of its length,
and which extends out through the side wall A' and the side beam D', and at its outer
end is provided with a suitable handle B'. Firmly secured in the side beam D¹
is a nut B in which the worm gear on the shaft B6 works. At about the center of
the shaft B, there is located a vertical rod J having a sleeve J2 surrounding the
shaft B, and the pin J³ projects through said sleeve into a groove on the shaft Be so
that in the operation of said shaft B the movement thereof operates the vertical
rod J. The upper end of said rod J extends through an eye J on the end of the
rod K, which passes through the receptacle E and is connected at its outer end
with the box G. It is obvious that by turning the handle B' the lower electrode B
can be moved toward the right, as shown in Figure 2, and in the same movement the
rod J acts on the rod K and moves the boxes F and G to the position shown, so that
the material contained in the box G passes from said box G through the port E² down
onto the top of the bottom electrode B. By turning the handle B', the lower
. electrode B can be moved to the position shown in dotted lines Figure 2, and in said
movement the rod J acting on the rod K will move the boxes F and G so that the
box F will register with the port E', as shown in dotted lines, Figure 2, and the
material will drop down onto the top of the lower electrode B.
The amount of material placed in the boxes F and G being known, it is obvious that
a determined amount of material to be treated, can be brought within the influence of
the heat incident upon the formation of the arc between the opposite electrodes, and
an amount can thus be added proportional to the heat generated by the arc.
As the material is reduced between the electrodes, the same may be separated, and
thus provide room for more material, by operating the lifting screw C' and connecting
mechanism to raise the electrode C, which, while increasing the length of the arc between
the electrodes proper, does not break the circuit where the reduced material is a
conductor and forms then a part of the lower electrode.
From the above it is clear that the new material A³ to be treated is dropped onto

page_text: the lower electrode or onto the material previously smelted; consequently, as the-
electrode is moved toward its original position, the material brought directly within
the influence and in the path of the electric arc, the heat is fully utilized and a great
saving is accomplished over the furnaces where the material is not so directly and
positively brought within the influence of the arc, because, as previously stated, the-
heat necessary for smelting is of sufficient intensity only within the influence of the
are formed between the opposite electrodes, and the current is not consumed merely
in forming the arc. The movement of the lower electrode B, it will be understood.
does not break the circuit, but the arc moves correspondingly with the movement of
the lower electrode, as it is well known that the electric arc between two electrodes will
follow the path of least resistance, and, consequently, will be formed in those portions
of the two electrodes which are nearest to the other. When the electrode B is in the
position shown in full lines Figure 2, to receive new material on the right side, the
material on the other half of the electrode is within the influence of the arc, and as
the electrode B is moved toward the left to receive the material on the left side of
the electrode, the material which has been fed on the right side of the electrode B is
being acted upon by the electric are; consequently, it is clear that while the
electrode B is receiving new material, the electric are is acting on the material
previously received, so that the material is brought directly in the path of the moving
arc, and consequently within the direct influence of the heat incident upon the
formation of said arc.
Suitable openings L are provided in the hottom plate A2 through which the raw
material not acted upon by the arc may be withdrawn.
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:-
1. In an electric are furnace, an upper electro.le, a lower electrode, mechanism
for moving said lower electrode from its normal position to expose the same to receive
the material to be treated, mechanism for returning said lower electrode to its normal
position, and a feed mechanism for feeding the material to be treated onto said
lower electrode during the interval between the movements of the lower electrode.
from and back to its normal position.
2. In an electric arc furnace, an upper electrode, a lower electrode, mechanism
for moving said lower electrode from its normal position to expose the same to receive
the material to be treated, and a feed mechanism operated by the movement of said
lower electrode for feeding the material to be treated onto said lower electrode.
3. In an electric arc furnace, an upper electrode, a lower electrode, mechanism.
for moving said lower electrode from its normal position to expose the same to.
receive the material to be treated, and an intermittent feed mechanism connected
to the upper electrode and adapted to be operated by the said movement of the
lower electrode to intermittently feed the material to be treated onto said lower
electrode.
4. In an electric arc furnace, an upper electrode, a lower electrode, mechanism
for varying the distance between said electrodes, mechanism for moving said lower
electrode from its normal position to expose the same to receive the material to be
treated, and a feed mechanism connected to said, upper electrode and adapted to be
operated by the movement of the said lower electrode to intermittently feed the
material to be treated onto said lower electrode.
Duted this 26th day of T
1007
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents..