Improvements in the Means for and Method of Melting Metals and other Materials by Electricity.
Year: 1892

page_text: Date of Application, 29th Aug., 1852-Accepted, 15th Oct., 1892
Improvements in the Means for and Method of Melting Metals and
other Materials by Electricity.
I, AUGUST FRIEDRICH WILHELM KREINSEN, of 64 gr. Brunnenstrasse,
Ottensen, in the German Empire, 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 :-
This invention relates to the melting of metals and other materials by the aid of
electricity.
According to these improvements, the fusion of the material is effected in
electrically heated crucibles, or it may be primarily fused by being brought into
contact with a carbon electrode through which a sufficient electric current is caused
to pass.
I will describe my invention with reference to the accompanying drawings, which
illustrate various modifications of my improvements.
In Figure 1, which is a vertical section, k is a positive electrode which may best
consist of electric light carbon, and m is the negative electrode which consists of
the material to be melted. Both of the electrodes are movable and adjustable, so
that they may be moved towards and withdrawn from each other as may be
required, either by hand or by mechanical means. The fusion of the material is
thus effected on the passage of a sufficient current, without the use of a second
carbon electrode. The electrodes km, are arranged above the centre of the
Fcrucible gr and above them there is arranged the cap or shield, to prevent the
escape of any sparks and splashes from the fusing material. As the material is
melted, it drops into the cavity t, of the crucible, where it is re-melted or kept in
a state of fusion by the means hereinafter described..
In the modification represented by Figure 4, a vertical section, of which Figure 5
is a plan, the positive electrode instead of being a carbon rod, is a rotary carbon
disc against which the negative electrode m of the material to be melted, is pushed.
The current may be conveyed to the disc by means of the strong spring w, pressing
upon the disc spindle.
The means which I employ for heating the crucible or receiver are illustrated by
Figures 1, 2 and 3. One or more spirals of platinum wire or ribbon, Figure 1,
may be embedded in the walls of the crucible or surround it closely. This platinum
circuit is arranged in a shunt from the main circuit and the heat produced by the
resistance of the platinum to the passage of the current, will be transmitted through
the crucible to the contents.
A. modification of the arrangement illustrated by Figure 1, is illustrated in
vertical section and in plan by Figures 2 and 3. In this case, an ordinary
plumbago crucible g, of high electrical resistance, is inserted in a thin platinum
vessel as shewn. The platinum vessel receives current through the terminals no,
between which the continuity of the metal is destroyed, so that the current is
compelled to traverse the whole of the metal of the vessel p, thereby raising it to a
temperature of from 1600 to 2000 deg. C. if desired. This high temperature is
transmitted through the crucible to the material contained therein and effects its
fusion or maintains it in a melted condition as may be required. The platinum
vessel may be surrounded by a non-conductor of heat, and so prevent the radiation
of heat and waste of platinum. Suitable non-conductors for the purpose are mica,
asbestos, and wood ashes. The apparatus may be advantageously worked in a
vacuum, and if the contents of the crucible are also cast in a
vacuum the
occurrence of blisters and air bells in the ingot or casting will be avoided.
It is well understood that if a sufficient current of electricity be sent through
an electric light carbon, it may be raised to a white heat, and I may take

page_text: advantage of this fact in the construction of my crucibles and receivers, as
illustrated by Figures 6, and 7, both of which are vertical sections. As shewn
by Figure 6, a cylinder of carbon k, is formed, and is provided with a perforated
bottom. The material to be melted is filled, in pieces, into the cavity of the
cylinder, and upon the closing of the circuit it will begin to fuse in a short time
owing to the heat generated by the resistance of the carbon to the passage of
the current. The receiver may be coned at its ends in opposite directions,
and be held at the coned parts by the conducting clips a and b, one of which, a,
is represented in plan by Figure 6. This upper clip a, is preferred to be
removable, whilst the lower one b, is fixed. The coned lower part of k being
pressed into the coned recess in , the upper clip a is firmly pressed with its
coned recess upon the upper conical part of the receiver or crucible k, when it
is clamped by the bolt shewn in the figure. The current enters by a, and leaves
through. When the material is melted, a plug, at the bottom of the crucible,
may be withdrawn. The density of the current may be regulated as may be
required from time to time by means of a rheostat or set of resistances w.
The
Instead of making the carbon crucible a part of the circuit as illustrated by
Figure 6, the material m, may be used in the form of a rod as an electrode,
the crucible forming the other electrode, as indicated by Figure 7.
electrode my is brought into contact with the bottom of the crucible, and the
current, owing to the great resistance of this point of contacts, will generate
sufficient heat to fuse the electrode m, which is moved or allowed to fall down-
wards as the melting proceeds so as to maintain the circuit. In this form of the
apparatus also, the density of the current may be regulated by the set of
resistances 20. The bottom only of the crucible is coned, and a single holder
such as that illustrated by Figure 6 will suffice. When the material is melted,
the crucible may be inverted to pour out the contents by means of a pair of tongs.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same may be performed, I declare that what I
claim is
-
1. The method of melting metals and other materials by the aid of electricity,
which consists in employing the metal or material as one of the electrodes, the
other electrode being carbon, and in arranging the electrodes above an electrically
heated crucible or receiver into which the metal or material drops as it is fused and
in which it is re-melted or maintained in a state of fusion; substantially as herein-
before described.
2. In electrical melting apparatus, the combination and arrangement with a
carbon electrode, of an electrode consisting of the material to be melted, a crucible
or receiver below the electrodes, and a cap for the crucible; substantially as
herein before described and as illustrated by Figures 1 to 5 inclusive of the accom-
panying drawings.
3. A crucible for melting or maintaining in the melted condition metals
and other materials, consisting of an insulated or non-insulated plumbago pot
surrounded by a platinum conductor through which a current of electricity can be
caused to pass, constructed and arranged substantially as hereinbefore described and
as illustrated by Figures 1 to 5 inclusive of the accompanying drawings.
4. A carbon crucible for melting metals and other materials by electricity, con-
structed and arranged substantially as hereinbefore described and as illustrated by
Figure 6 of the accompanying drawings.
5. A carbon crucible for melting metals and other materials, constructed and
arranged substantially as herein before described and as illustrated by Figure 7 of
the accompanying drawings.
Dated this 27th day of droust AD 1000
WILLIAM E. HEYS,
Agent for the Applicant.