Improvements in or relating to Heating Metals Electrically.
Year: 1894

page_text: Date of Application, 26th June, 1894-Accepted, 28th July, 1894.
COMPLETE SPECIFICATION.
Improvements in or relating to Heating Metals Electrically.
A communication by CHARLES LEWIS COFFIN, of 980, Jefferson Avenue, Detroit,
in the County of Wayne, and State of Michigan, United States of America,
Chemist.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool and 6, Bank Street,
Manchester, both in the County of Lancaster, and 323 High Holborn, in the
County of Middlesex, Civil Engineer, 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 has for its object to provide a new and improved method of heating
metals electrically.
To accomplish this object the present invention consists in heating the metal,
connecting it with one terminal of a generator of electricity, bringing it in contact
with a liquid electrode connected with the other terminal of said generator, and
establishing a voltaic are between the two electrodes. The invention also consists
in heating the metal previous to its immersion in a liquid electrode, connected to
one terminal of a source of electric energy, the said metal being connected to the
other terminal of the source of electric energy, and establishing a voltaic arc
between the electrodes. The invention also consists in dipping a heated piece of
metal into a liquid, passing an electric current through said metal and liquid, and
establishing a voltaic arc between said electrodes.
The invention may be carried into effect by the apparatus illustrated in the
accompanying drawing, in which
Figure 1 is a sectional elevation of the apparatus; and
Figures 2 and 3 are detail views hereinafter explained.
My correspondent has discovered that if a heated metal electrode connected with
one terminal of an electric generator, be so introduced into a liquid electrode
connected with the other terminal of the generator, that a number of minute
voltaic arcs will be formed between the two electrodes, a metal electrode will
become rapidly heated. Since the date of his discovery, other parties have
proposed to heat a metal electrode by dipping the same into a liquid electrode,
under the supposition that, by means of the electrolytic action, hydrogen gas
gathers on the metal electrode, and thus, by the high resistance of this gas, a
heating effect is produced, but he believes that this is a mistaken idea. Thus, if
a metal electrode be placed in a liquid electrode, and the current then turned on,
while hydrogen gas will be evolved in considerable quantity, little or no heat effect
will be produced, but, if the metal electrode be first heated to or over the boiling
point of water, so that, when put into the liquid, a film of vapor will be formed
around the metal electrode, a number of minute voltaic arcs will be sprung between
the two electrodes, and the metal electrode will become rapidly heated. Or if,
the current being turned on, the metal electrode be brought in contact with the
liquid electrode, and then withdrawn to form a voltaic arc between it and the
liquid electrode, the metal electrode may be then, after becoming heated, immersed
in the liquid electrode, and a number of minute voltaic arcs will be formed.
In the drawings, A. represents an insulated support carrying a tank H, adapted
to contain fluid, which tank, or if preferred, the liquid within the tank, is connected
by a conductor y with one terminal of a generator of electricity. B represents a
support for a metal electrode D, which may be held in a clamp C pivoted at E to
support B, so that said electrode D may be dipped into the fluid in said tank II.

page_text: to establish the arc. As shown in Figure 1, tank I may be formed of a metal
vessel 1', lined with a porcelain or other suitable lining F, and provided with a lug
or binding screw L for connection with conductor y. If desired, a second
support B, carrying a clamp C' pivoted at E' to carry an electrode D', may be
used, in which case it is well to make clamp C longitudinally movable by screw
shaft S. threaded nut and collar », as is well understood. By perforating
lining F, the fluid comes in electrical contact with tank H. When the two
electrodes D D' are used, they both become hot and might be welded together.
I represents insulating material. For the purpose of heating the metal electrode,
a carbon Q, provided with metal connections T T', may be included in a high
resistance shunt circuit y', and one or more electrodes, represented by dd',
may be placed in a receptacle K preferably lined with insulating material O, so
that their ends will rest on carbon Q and therefore become heated before being
used.
As shown in Figure 2, the electrode D has been brought in contact with the
liquid in tank H, and then withdrawn to form a voltaic are between the two
electrodes, for the purpose of heating electrode D, after which it uny be partially
immersed in the liquid electrode, as shown in Figure 3, still maintaining the voltaic
Arce.
As illustrated in Figure 1, the electrode D or electrodes D D' are first heated
until their ends are at the boiling point of water, or above that, and this may be
done in the way shown in Figure 1, or in any other suitable way. The current
then being established, by partially immersing electrode D into the liquid in
tank II, a number of minute voltaic ares will be formed between the two electrodes,
and electrode D is pidly heated.
As shown in Figures 2 and 3, the electrode D, after the current has been
established, is brought in contact with the liquid in tank H, and then slightly
withdrawn, to form a voltaic are, and when the end of the electrode D has become
heated, it is slowly immersed in the liquid electrode, the voltaic ares being continued
between the two electrodes, and becomes rapidly heated. This process may be
carried on with either alternating or continious currents. With a continuous
current, it is preferable, though not essential, to connect the inetal electrode with
the negative terminal of the generator.
The liquid electrode may be a solution of soda carbonate, potassa-carbonate,
soda or potash nitrate, salt, borax, caustic soda, or potash, et cetera, or acid, alkaline
or neutral salt.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. The herein described method of electrically heating metal, consisting in
heating the metal, connecting it with one terminal of a generator of electricity,
bringing it in contact with a liquid electrode connected with the other terminal of
snid generator, and establishing a voltaic are between the two electrodes.
2. The herein described method of electrically heating metal, consisting in
henting said metal previous to its immersion in a liquid electrode, connected to one
terminal of source of electric energy, the said metal being connected to the other
terminal of the source of electric energy, and establishing a voltaic are between the
electrodes.
3. The herein described mode of heating metal, electrically, consisting in dipping
a heated piece of metal into a liquid, passing an electric current through said metal
and liquid, and establishing a voltaic are between the electrodes.
Dated this 25th day of June 1894
WM. P. THOMPSON & Co.,
Agents.