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

page_text: Date of Application, 22nd May, 1894-Accepted, 29th Sept., 1894
COMPLETE SPECIFICATION.
Improvements in or relating to Apparatus. for 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.
1, 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 consists in an improvement in apparatus for heating metal
electrically, hereinafter fully described and claimed.
In the accompanying drawing:-
Figures 1 and 2 are sectional elevations of the improved apparatus.
Figure 3 is a cross section of Figure 2.
Figure 4 is a detail vertical sectional view through the conductor D and one of
the electrodes: and
:
.
it may
Figure 5 is an elevation of the apparatus adjusted to produce the voltaic arc.
A, represents a table suitably supported and insulated J, a goose neck or
standard secured on and rising from table A, and carrying on its end a collar K :
N, a rod which passes through collar K. For raising and lowering rod N,
be screw threaded and engage with a nut M which rides on collar K and is kept
in place by lugs L. I represents a block of insulating material carried on rod N,
in which are secured a metal rod E and a series of insulated high resistance
electrodes C, preferably of carbon, each electrode C being provided with a contact
plate of metal G. D represents a conductor adapted to move in electrical contact
with rod E, and carrying a brush F making contact with plate G on electrode C.
a represents a conductor, preferably terminating in a collar H, by which rod E
is connected with one terminal of a generator of electricity. B represents the
material to be heated, connected by conductor y with the other terminal of the
generator.
The operation of the invention is as follows
Material B being placed in position and connected with the generator,
electrodes C are brought in contact with B, thus establishing a circuit through
conductor, rod' E, conductor D, brush F, contact plate G, one electrode C,
material B and conductor y. When this electrode C becomes hot, brush F is
shifted to the contact plate G of the next electrode C, and when this second
electrode becomes hot, brush F is shifted to the next electrode C. As electrodes C
heat very readily, and retain their heat a considerable time, quite a number of
them can be heated, and then, by shifting brush F more rapidly, they are all
maintained at a high heat, and heat material B by incandescence. In this manner,
quite a long seam or joint can be brought to welding heat, with but little
expenditure of power, since the current need only be sufficient to heat one
electrode C to the desired temperature.
This incandescent process is especially useful in heating sheet metal for welding,
n cases where the arc process develops too much heat and where it is very difficult

page_text: to bring the edges to be welded into contact and pass a heating current across the
joint.
The electrodes C in Figure 1 are illustrated as arranged in a straight line, for
heating a straight seam, but it is evident that they may be arranged in any curve,
or in a circle, as shown in Figures 2 and 3. With the construction,shown in
Figures 2 and 3, conductor D may be in the form of a pulley loosely mounted
on rod N but insulated therefrom and from the electrodes C and in electrical
contact with an insulated contact plate E which is connected by conductor & with
one terminal of the generator, and the conductor D may be moved such as by a
band or belt P. The same apparatus can be used to heat by incandescence or by
the voltaic arc.
The apparatus in Figure 1 is intended for use by direct contact with the
material, but, by first bringing the electrode in contact with the material and then
raising it slowly from the material to the position shown in Figure 5, the current
being passing, a voltaic arc will be produced, which arc may be moved backwards
and forwards by moving the contact piece.
The method is not herein claimed of heating metal by subjecting the same to
the influence of a moving voltaic arc while simultaneously heated by radiation from
incandescent electrodes in proximity to, but not in contact with, the metal, as such
constitutes the subject matter of my Application for Letters Patent No. 9975
of 1894 filed cotemporaneously herewith.
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. In an apparatus for heating metal electrically, the combination of a plurality
of high resistance electrodes, metallic conducting clamps sustaining said electrodes,
and means for insulating said electrodes and clamps from each other, a movable
contact device connected to one terminal of a source of electric energy, and adapted
to make contact with said conducting clamps, severally and successively bringing
said high resistance electrodes into circuit, with the metal, and means for con-
necting the same to the other terminal of the source of electric energy.
2. In an apparatus for heating metal electrically, the combination, with a plurality
of high resistance electrodes insulated from the metal, means for connecting said
metal to the terminal of a source of electric energy, support for the electrodes,
means for raising and lowering said electrodes, a movable contact device, and
means for connecting said contact device to the other terminal of the source of
energy.
3. In an apparatus for electrically heating metal, the combination, with the
metal and means for connecting said metal to one terminal of a source of electric
energy, of a plurality of high resistance electrodes insulated from each other, a
movable adjustable support for said electrodes, a movable contact device connected
to the other terminal of the source of energy, and means for bringing said
electrodes severally and successively into the electric circuit.
4. In an apparatus for heating metal electrically, the combination, with a support
for the metal to be heated and means for connecting said metal with one terminal
of a generator, of a series of, high resistance electrodes insulated from each other,
means for bringing said electrodes in contact with the metal, and means for con-
necting said electrodes severally and successively with the other terminal of the
generator, substantially as shown and described.
5. In an apparatus for electrically heating metal by means of an electric
arc, the
combination of a plurality of electrodes, a contact device by means of which said
electrodes may be successively thrown in circuit, means for moving said contact
device, and means for maintaining an electric are between the metal and the
electrodes successively thrown in circuit.
6. In an apparatus for electrically heating by means of the electric arc, the
combination of a plurality of electrodes insulated from each other, a contact

page_text: device by means of which said electrodes may be successively thrown in circuit,
means for moving said contact device and means for maintaining an electric arc
between said electrodes successively thrown in circuit.
Dated this 21st day of May 1894.
WM. P. THOMPSON & Co.,
Agents.