Improvements in and relating to Electric Furnaces.
Year: 1896

page_text: Date of Application, 16th June, 1896-Accepted, 30th Jan., 1897
COMPLETE SPECIFICATION.
Improvements in and relating to Electric Furnaces.
We SCIPIONE REGNOLI, Engineer FERDINANDO LORI, Engineer, RICCARDO
PIGNOTTI, Engineer, Professor MAFFEO PANDALEONI, and MARCO BESSO
Merchant all of Via S. Andrea delle Fratte 12 Rome in the Kingdom of Italy 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 :-
The invention for which Letters Patent are now applied for, consists of an
electric furnace intended for chemical reactions, in which a combustible gas is
generated. Our improved furnace is especially suitable for use in the manufacture
of carbides and in particular of calcium carbide.
As an example we will take a furnace used for manufacturing carbide of calcium
in which oxide of carbon is generated.
Our furnace consists of a case or shell without a bottom lined internally with
some refractory material which must be a very feeble conductor of electricity (for
instance-a mixture in suitable proportion of charcoal aud kaolin).
The bottom is formed of a conducting metallic case containing a block of charcoal.
This case may slide on a metallic plate to which the current is carried by means of
a suitable conductor, and so may be easily charged. In the said block is a hole
through which the material produced in the furnace can flow out.
The whole rests on a plinth of suitable dimensions.
The case or shell of the furnace is closed on the top by means of a hood or cover
in which is an opening for the passage of the electrode and several holes for
permitting the escape of the gases generated in the furnace.
Above this first case or shell which constitutes the furnace proper is placed a
second shell the bottom of which serves or acts as cover to the first shell.
This second case is intended for the reception of the gases that are generated
during the reaction.
The charcoal which forms the upper carbon electrode is all inside the said
second shell, and through holes which do not allow the gases to escape are
introduced into the same shell, the conductor of the current and the rod which
serves to support the electrode and regulate its height.
This rod may also be used as a conductor of the current. A tube or pipe leads
the material into the furnace from the reservoir by means of a suitable mechanism
for instance, a valve or an Archimedean screw, or any similar mechanism.
A tube carries away from the second case the gases produced during the time
when the furnace is working, and the said tube takes the gases, which may or may
not pass through a gas meter, to a small furnace where the gases are burnt so as to
utilize their heating powers.
An important application of this heat is the use thereof for heating the material
before the same is introduced into the furnace, and for heating the chamber around
the furnace in order to maintain the same at a high temperature, thus decreasing
or diminishing the dispersal of heat.
The annexed drawing represents a concrete example for the application in the
ideas mentioned above. The gases, produced are burned and serve for previously
heating the material.

page_text: Figure 1, is the horizontal section of the furnace taken on the line X. Y. Z. and
Figure 2 is the vertical section on the line T. U. V.
The same letters in both figures refer to the same parts.
A is the case or shell of the furnace lined with refractory material. B is the
carbon block, which forms the lower electrode and in which is formed the hole C.
for the passage of material; the said block B rests on a metallic plate D,
and E. is the air chamber which is maintained at a high temperature by
burning the gases generated during the reaction, F is the upper shell or case
where the gases are collected; H. is the upper electrode carried by the rod G,
through which rod in this instance, the current is conducted to the electrode, I is
the mouth of the tube which carries out the gases L is the reservoir for the
material to be introduced into the furnace; M, the small gas furnace in which the
gases are burnt, and N the screw conveyor for regulating the introduction of
the material through the tube or pipe O, P is a carbon plug used for closing the
hole through which the molten material flows out which plug is supported by the
lever Q, which is worked externally and can be regulated by means of a spring or
weight . R is a tunnel through which passes the trolley S. into which the
material produced is delivered through the hole C when the plug P is withdrawn.
The inventors reserve to themselves the right to modify the type of the furnace
according to the requirements of the several applicatious but maintaining the
fundamental ideas throughout.
Having now particularly described the nature of our said invention and in
what manner the same is to be performed, we declare that what we claim is :-
1. The recovery, with or without the aid of a gas-meter, of the combustible
gases, which are generated in the reaction of electric furnaces, the utilization or
use of their heating power, either for previously heating up the material to be
worked, or else for maintaining the space around the furnace at a high temperature
or for other purposes.
2. In an electric furnace the development of chemical reactions, without any
contact with air, in an atmosphere formed by the same gases which are generated
in the furnace.
3. An air chamber surrounding the furnace which is heated by burning the
recovered gases with the object of diminishing the dispersal of heat from the
furnace.
4. A furnace having a bottom in form of a sliding case easily changeable so as
to avoid the breaking up of a portion of the furnace when changing the electrodes
substantially as described.
5. Covering or lining the sides of the furnace with refractory material which is
a very feeble conductor of electricity, in order to avoid the formation of lateral
ares, substantially as described.
6. An electric furnace constructed substantially as described with reference to
the accompanying drawing.
3000
W. P. THOMPSON & Co.,
322 High Holborn, London, W.C., Patent Agents for the Applicants.