Improvements in Electric Furnaces and Apparatus for Heating, Lighting, and Carrying on Chemical Processes, and in the Working of such Furnaces or Apparatus.
Year: 1887

page_text: Date of Application, 15th Jan., 1887
Complete Left, 15th Nov., 1887
Complete Accepted, 16th Dec., 1887
Improvements in Electric Furnaces and Apparatus for Heating,
Lighting, and Carrying on Chemical Processes, and in the
Working of such Furnaces or Apparatus.
I, SEBASTIAN ZIANI DE FERRANTI of 5 Stanwick Road, West Kensington, in the
County of Middlesex, Electrician, do hereby declare the nature of this invention to
be as follows:-
According to this invention I form an electric furnace in such a manner that the
current which circulates in the crucible or container of the furnace is not conducted
there from the outside but has local currents induced in it by a varying or
alternating magnetic field or it might be by a rotating or moving field." In
this way an electric furnace is obtained without electrodes in the crucible thereby
avoiding all action of electrodes upon any metal or ore that is being melted or
reduced therein.
One way in which the furnace may conveniently be formed is to make the crucible
of an oblong annular shape placed horizontally and with magnet core pieces rising up
through the open space in the centre and outside each of the two longer flattened sides
and with an insulated conductor wound between the pole pieces below the crucible.
Preferably I insulate the conductor with fire clay or asbestos or slag.
The central and outer pole pieces are connected at the bottom so as to form two
horse shoe magnets one embracing one of the longer sides of the crucible and the
other the other side of the crucible. Connecting pieces are also placed over the tops
of the pole pieces but these are removeable so that the crucible may be readily got at
and charged with material.
The crucible forms a continuous trough open at the top and a suitable lid is provided
by which it can be covered over when the furnace is in operation. The whole furnace
may be mounted on trunnions projecting from the centre of its longer sides-so that
it may be tilted and the contents of the crucible when liquid poured out from one of
its ends.
When the furnace is to be used for melting metal or reducing ores I form the
crucible or container of refractory material, and if necessary line it with a lining of
any refractory substance.

page_text: When a metallic ore is to be reduced in the crucible a strip of wire or blanks or
pieces cut from thin sheets of the metal contained in the oro or with which
the metal in the ore is to be alloyed may be placed around the interior to give
conductivity at starting or a granulated conductor or a flexible carbon stick or
carbonized paper may be placed around the interior of the crucible to effect the
same object.
When carbon is required to be used in the reduction of the ore thin layers of carbon
may be alternated with thin layers of ore-or a gas or vapour rich in carbon might
be supplied to the crucible as the process of reduction is being carried on.
For some
metallic processes a vacuum may when required be formed in the crucible to extract
gases.
When several furnaces are used they may be placed in parallel on the circuit of the
exciting machine the current may also be fed to each furnace through what are known
as distributors.
Induction resistances may also be used to regulate the working of the several
furnaces..
If the furnace is to be used for boiling or heating liquids a pot of brass or copper
may be substituted for the refractory crucible.
In this way the furnace may be used for boiling water or for heating generally-
either for cooking or for other purposes as for example for heating water in
pipe or vessel forming part of a circulating hot water heating apparatus. The
furnace can also be used for effecting the decomposition of liquids contained in a
pot or vessel of insulating material or the precipitation of metal from them in cases
where it is undesirable to act upon the liquids by electric currents passing through
electrodes.
When the furnace is to be used for obtaining light a shallow crucible left open at
the top may be used and powdered charcoal be supplied to it or a metal such as
platinum or iridium-the crucible used may in this latter case be conveniently formed
of lime.
n
CARPMAEL & Co.,
Agents for the Applicant.

page_text: I, SEBASTIAN ZIANI DE FERRANTI, of 5 Stanwick Road, West Kensington, in the
County of Middlesex, 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 :—
According to this invention I form an electric furnace in such a manner that the
current which circulates in the crucible or container of the furnace is not conducted
there from the outside but has local currents induced in it by a varying or
alternating magnetic field or it might be by a rotating or moving field. In
this way an electric furnace is obtained without electrodes in the crucible thereby
avoiding all action of electrodes upon any metal or ore that is being melted or reduced
therein.
One way in which the furnace may conveniently be formed is to make the
crucible of an oblong annular shape placed horizontally and with magnet core pieces
rising up through the open space in the centre and outside each of the two
longer flattened sides and with an insulated conductor wound between the pole
pieces below the cruciblo. Preferably insulate the conductor with fire clay or
asbestos or slag.
The central and outer pole pieces are connected at the bottom so as to form two
horse shoe magnets one embracing one of the longer sides of the crucible and the other
the other side of the crucible. Connecting pieces are also placed over the tops of the
pole pieces but these are removeable so that the crucible may be readily got at and
charged with material.
The crucible forms a continuous trough open at the top and a suitable lid is
provided by which it can be covered over when the furnace is in operation. The whole
furnace may be mounted on trunnions projecting from the centre of its longer sides-
so that it may be tilted and the contents of the crucible when liquid poured out from
one of its ends.
Figure 1 of the drawings hereunto annexed is a side elevation and Figure 2 a
vertical transverse section of an electric furnace constructed in the above manner-

page_text: A is the oblong annular crucible of a trough form in cross section and A' a lid for
covering it in at the top. B Bare magnet pole pieces formed of a number of thin plates
of soft iron placed together side by side-cach plate being cut to the form shewn at
Figure 2 so as to rise up through the open space in the centre and outside each of the
two longer flattened sides of the crucible. C is the insulated conductor wound
in coils around the inner pole piece between it and the outer pole pieces. D is
a cast iron frame mounted on trunnions and carrying within it the magnet
and crucible. E is insulating material placed between the magnet and the frame.
Faro blocks built up of a number of thin plates of soft iron placed above the
lid A of the crucible to connect the top of the inner pole piece with the top of the
outer ones.
One of the ends of the crucible which project beyond the pole pieces is provided
with a readily removeable lid to allow of the material which is to be operated
on being placed into the crucible and at the other end a tap hole is provided
or other provision made for allowing the material being poured out when reduced to
a molten state.
Another way in which the electric furnace may be constructed is shewn in vertical
section in Figure 3. In this construction a coil of insulated conductor is placed above
the crucible as well as below it and the pole piece by which each side of the crucible
is surrounded is formed from concentric rings of sheet iron, each formed of an
iron sheet bent to form and with its ends overlapping.
When the furnace is to be used for melting metal or reducing ores I form the
crucible or container of refractory material, and if necessary line it with a lining of
any refractory substance.
When a metallic ore is to be reduced in the crucible a strip of wire or blanks
or pieces cut from thin sheets of the metal contained in the ore or with which
the metal in the ore is to be alloyed may be placed around the interior to give
conductivity at starting or a granulated conductor or a flexible carbon stick or
carbonized paper may be placed around the interior of the crucible to effect the
same object.
When carbon is required to be used in the reduction of the ore thin layers of
carbon may be alternated with thin layers of ore--or a gas or vapour rich in carbon
might be supplied to the crucible as the process of reduction is being carried on.
For some metallic processes a vacuum may when required be formed in the crucible
to extract gases.
When several furnaces are used they may be placed in parallel on the circuit of the
exciting machine the current may also be fed to each furnace through what are known
as distributors.
Induction resistances may also be used to regulate the working of the several
furnaces.
If the furnace is to be used for boiling or heating liquids a pot of brass or copper
may be substituted for the refractory crucible.
In this way the furnace may be used for boiling water or for heating generally
either for cooking or for other purposes as for example for heating water in a
pipe or vessel forming part of a circulating hot water heating apparatus. The
furnace can also be used for effecting the decomposition of liquids contained in a
pot or vessel of insulating material or the precipitation of metal from them in
cases where it is undesirable to act upon the liquids by electric currents passing
through electrodes.
When the furnace is to be used for obtaining light a shallow crucible left open at
the top may be used and powdered charcoal be supplied to it or a metal such as
platinum or iridium-the crucible used may in this latter case be conveniently
formed of lime.
At Figures and 5 1 have shewn a plan and vertical section of a furnace adapted
to be used for this purpose. In this case the pole picces might be made to
surround the shorter ends of the crucible whilst the longer sides are exposed and
left uncovered.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. An electric furnace or apparatus in which metal or material whilst contained
in a suitable crucible or vessel is heated or melted by currents induced directly
in it.
2. An electric furnace or apparatus composed of a crucible or containing vessel
heated by induced currents circulating in it or in the material contained in it without
such currents being conducted there from the outside.
3. An electric furnace or apparatus composed of an annular crucible or vessel
of refractory material in a varying or alternating magnetic field or in a rotating or
moving field.
4. An electric furnace or apparatus composed of an annular crucible or vessel of
conducting metal or material in a varying or alternating magnetic field or in a rotating
or moving field.
5. The construction of electric furnaces or apparatus substantially in the manner
herein before described and illustrated in the drawings annexed.
CARPMAEL & Co.,
Agents.