Improvements in Insulating Means for Electric Furnaces.
Year: 1898

page_text: Improvements in Insulating Means for Electric Furnaces.
A communication from the ALUMINIUM-INDUSTRIE ACTIEN-GESELLSCHAFT, of
Neuhausen, Switzerland.
I, WILLIAM LLOYD WISE, of 46, Lincoln's Inn Fields, in the County of London,
Consulting Engineer and Chartered Patent Agent, do hereby declare the nature
of this invention to be as follows:-
In the construction of electric furnaces, in such cases, for example, when it is
desired to insulate horizontal electrodes from one another in a permanent and
effective manner, the necessity is often felt of having a material which is not
electrically conductive and which shall also be capable of resisting the heat of the
electric arc, or of the molten masses. This necessity could not be satisfied here-
tofore because all known non-conducting materials are not fire-proof at the tem-
peratures that have to be dealt with in this respect, and their bad heat-conducting
power does not allow them to be cooled by the usual cooling means to such an
extent as to render them sufficiently resistant.
Now, this invention consists in forming an insulating layer of conductors--
particularly metals-and of non-conductors (not excluding air) in such a manner
that in one form-conductors extending to the melting hearth are arranged
in alternate layers with non-conductors or-in another form-the mass of a non-
conductor is traversed by bars of a conducting material. The arrange-
ment thus acts as an insulating device and withstands at the same
time the highest temperature in usc, because the metal or conductor
can be readily cooled by means of air or water in such a manner that
it will not melt and also by contact with the non-conductor, keeps the latter so
cool that the said non-conductor remains perfectly fire-proof. In the course of
the melting, in the case of certain materials, for example, calcium carbide, there
is also formed a coating of the solidified melting product which in this condition
has little or no conductivity whatever, and which therefore further increases the
insulation.
In the accompanying drawings Figs. 1-4 show various forms of construction
of insulating bodies of this kind.
Fig. 1 illustrates a form of construction in which a conductor a, which is capable
of being cooled, alternates in layers with a non-conductor b. The conductors or
the layers forming the same and arranged in the form of plates, are each provided
with a cooling channel a° of rectangular form in cross section for the purpose of
allowing of cooling by means of water, air etc. This cooling channel extends
through the whole length of the plates.
Fig. 2 shows a form of construction in which a non-conducting mass 61 is
traversed by bars a¹ of conducting material. The bar-shaped conductors a¹ are
inserted in corresponding recesses in the non-conductor 6' which in this case has
the form of a perforated or open-work body or grating. The cooling of the con-
ductors may be affected by means of pipes c which extend through the same.

page_text: carbide there is also formed a coating of the solidified melting product, which
in this condition has little or no conductivity, and which therefore further in-
creases the insulation.
The drawings accompanying my Provisional Specification show various
examples of insulating means according to this invention.
Fig. 1 illustrates an example in which a conductor a, which is capable of being
suitably cooled, alternates in layers with a non-conductor b. The layers of the
conductor, which are in the form of plates, are each provided with a cooling
channel a of rectangular form in cross section for the purpose of enabling them
to be cooled by means of a suitable fluid, as water or air. This cooling channel
extends through the whole length of the plates.
Fig. 2 shows an example in which a non-conducting mass 61 is traversed by
bars a¹ of conducting material. The bar-shaped conductors a¹ are inserted in cor-
responding recesses in the non-conductor 6', which in this case has the form of
a perforated or open-work body or grating. The cooling of the conductors can be
effected by means of pipes c which extend through the same.
Fig. 3 illustrates an example suitable for use in cases where the molten mass
is a non-conductor. In this example the conductor consists of bodies a which
are arranged side by side at certain equal distances apart and which are provided
in their lower parts with cooling channels aº of circular cross section for the
purpose of cooling. The free or vacant intermediate spaces 60 between the several
bodies effect the insulation in this arrangement, because at the commencement of
the operation these intermediate spaces contain air, which is a non-conductor,
whilst after melting has been effected the molten mass, which solidifies and fills
up the intermediate spaces, acts as a non-conductor or insulating material.
case,
Fig. 4 illustrates an arrangement of insulating means of this kind in the lower
portion (viz. the crucible or melting hearth) of an electric shaft furnace. In this
the bodies a that are shown black in cross section are of conducting
material and are provided, for the purpose of cooling, with passages for a suitable
cooling-agent, as water or air, whilst the intermediate spaces between these bodies
contain a non-conducting material. or separate non-conducting bodies b. The
electrodes E E2 are each separately insulated above and below by means of such
non-conducting material or bodies b, whilst the insulation of the electrodes from
one another is effected by means of the melting-hearth.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is
-
1. Insulating means for electric furnaces in which non-conductors of electricity
alternate with, or are traversed by, conductors of electricity that are in contact
with the non-conductors and are adapted to be cooled, so that the non-conductors
can be maintained at a suitably low temperature by the conductors.
2. Insulating means for electric furnaces constructed and arranged as herein-
before described with reference to and shown respectively in Fig. 1, in Fig. 2,
in Fig. 3, and in Fig. 4 of the drawings accompanying my Provisional Specifi-
cation.
D L
2011 1
T 1
1000
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Chartered Patent Agent.