Improvements in Electric Furnaces.
Year: 1895

page_text: Date of Application, 17th Apr., 1895-Accepted, 17th Apr., 1896
COMPLETE DI MUIFICATION.
Improvements in Electric Furnaces.
I, GEORGE DEXTER BURTON, a citizen of the United States, residing at
7 Water Street, Boston, in the County of Suffolk, in the State of Massachusetts,
United States of America, Electrician, do hereby declare the nature of my inven-
tion and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement:-
This invention relates to an apparatus for heating metals to the fusing point or
to a working heat and for smelting ores, by means of an electric or voltaic arc
sprung between the metal or ore and an electrolytic bath.
The objects of the invention are to provide a simple, cheap, and convenient
apparatus for this purpose. The form herein shown is especially adapted for use
as a forge for blacksmiths.
The invention consists in certain novel features of construction and combination
of elements hereinafter set forth and claimed.
Figure 1 of the accompanying drawings represents a plan of this apparatus.
Figure 2 represents a vertical longitudinal section thereof on line 2-2 of
Figure 1.
Figure 3 represents a vertical longitudinal section thereof on line 3--3 of
Figure 1.
Figure 4 represents a vertical transverse section thereof on line 4--4 of
Figure 1.
Figure 5 represents a front elevation, the front wall being partly in section
showing the studs for supporting the negative terminal and the insulated sockets
for said studs.
Figure 6 represents an enlarged vertical section of one of said sockets, the stud
and a transverse section of said terminal.
A vessel 10, preferably in the form of a tank, and constructed of or lined with a
material which is a non-conductor of electricity, is designed to contain a bath 20
through which an electric current is passed. If constructed of wood or earthenware
this vessel is coated on its inner surface with asphaltum or coal tar, in the same
manner in which tanks for electro-plating purposes are usually coated. Such a
coating prevents the tank from absorbing the solution and thereby avoids short
circuiting of the current through the walls of the tank, which might occur under
a heavy voltage, if such walls were saturated with the solution. When constructed
of wood the joints may be covered by strips 11 which prevent shrinkage and
render the tank tight. This vessel when constructed as herein shown is provided
with a vertical transverse partition 12 near one end and a longitudinal partition 13
near one side. These partitions or screens divide the vessel or tank into a hearth
compartment 17, an anode compartment 18 and a pump compartment 19, the anode
compartment being provided with a cover 15 to protect the anode. These
partitions 12 and 13 are provided with holes 14 below the surface of the bath so
that the solution may How freely from one compartment to the other or they may
if desired, be in the form of reticulated screens composed of non-conductive
material.
The bath 20 partially fills the vessel or tank 10 and is composed of an
electrolyte having a density greater than water and capable of evolving
hydrogen, being an electrolyte which will cause with the electric current under
proper conditions, the formation of a voltaic arc between the metal to be heated
and the solution. This bath may consist of a solution of chloride of sodium

page_text: of a density of 1050 for small work, but when larger pieces of metal are to be
heated or ore is to be treated, the density should be increased according to the size
of the article to be heated. I have used for this purpose a solution of sal-soda of
a specific gravity of 1.305 at 84 degrees Fahrenheit; also a solution of equal parts
of sal-soda and cream of tartar of a specific gravity of 1.255 at 77 degrees
Fahrenheit ; also a solution of water, carbonate of soda, and borax in the
proportion of three quarts of water to twelve pounds of carbonate of soda and one
pound of borax.
• An anode plate 30 is disposed in the solution, preferably in the anode compart-
ment 18 of the vessel 10. This anode is preferably in the form of a serpentine
plate and composed of lead. This anode plate is provided at one end with a copper
conductor 31 which extends through a hole in the cover 15. and is provided with a
binding post 32 above said cover for connection with the electric circuit. The
location of the anode within the compartment prevents contact of the work therewith
and avoids a short-circuiting of the current.
A hearth 40 composed of fire clay or other suitable non-conductive material is
supported in the vessel on a suitable bed 45. This bed is composed of fire clay or
any non-conductive material and it supports the hearth in such manner that the.
solution may flow underneath the latter as illustrated in Figures 2 and 4. As shown
it is provided with openings 46 at its top. The hearth is preferably provided with
an irregular surface on its upper side preferably formed by a number of grooves 41.
It is also provided with perforations 42 which extend from the bottom of the
grooves through the hearth, and open into the space beneath the hearth. The
grooves 41 may be disposed a greater or less distance apart and ribs 43 having flat
bearing surfaces of greater or less breadth may be formed between the grooves.
When the
A pump 60 is disposed in the vessel or connected therewith, preferably in the
compartment 19. This pump is used to change the level of the solution in the
main or open hearth compartment 17. The barrel of the pump is attached at one
end to a plate 62 fastened to suitable supports 63 and 64. The plate 62 is provided
with a pipe 61 which serves as an inlet and discharge tube for this purpose.
This
pump barrel is preferably disposed on an incline and rests near its ends on blocks 65
and 66. The piston 67 is provided with a piston rod 68 which extends through the
front side of the tank. The upper end of the pump barrel is closed and the lower
end thereof is open through the tube 61. When the piston rod is pulled out a
portion of the solution is drawn into the pump barrel and the level of the solution
in the hearth compartment is lowered below the surface of the hearth.
piston rod is pushed inward the liquid is driven out of the pump barrel and flows
through the openings 14 in the partitions. or screens into the main or hearth
compartment 17 and elevates the solution therein to a level with or a plane above
the surface of the hearth. The solution flows readily underneath the hearth
through the openings 46 in the sides of the bed and passes freely through the
vertical holes 42 in the hearth to the grooves 41 on the upper surface thereof and
if necessary it overflows the surface of the hearth between said grooves. In order.
to form the are on the underside of the material being heated it is necessary to have
some of the solution on the under side thereof and these grooves enable the solution
to come into electrical connection with the underside of the work so that an arc is
formed thereunder.
A terminal 70 in the form of a bar composed of copper or other suitable..
conductive material, is supported at the front edge of the tank on insulated studs 71.
One end of this bar is provided with a socket for receiving a conductor connected
with the negative pole of the electric source and with a set screw 75 for clamping
the conductor in the socket. This bar is preferably bevelled and serves as a rest
on which the tool or implement for grasping the article to be heated may form..
contact for closing the circuit. To secure firmness of the support and prevent
moisture from entering the wall of the tank or vessel, sockets 72 of porcelain or
other suitable non-conductive material, such as vulcanized fiber, are inserted in the
front wall of the box. These sockets are preferably provided with enlargements 73

page_text: near their tops which enlargements project above the recessed edge of the side wall
of the vessel. The supporting studs 71 for the bar 70 project into these sockets
and a non-conductive composition 74 preferably composed of sulphur and grease
melted together, is filled into the sockets and cements the studs therein, making the
supports for the terminal strong, water-tight and non-conductive.
A conductive rod 80 is supported at one side of the tank in any suitable manner
and adapted to slide to bring one end into contact with the terminal 70. As shown
the rod is supported in porcelain eyes 81 adjusted in metal holders 82 inserted in
the upper end of the longitudinal partition 13. An electrode 90 is hinged to the
rod 80 and is adapted to rest at its free end upon the work on the hearth 40 to
establish electrical connection therewith. This electrode may be of any suitable
form. As shown it is forked to rest upon the heels of a horse shoe to be heated.
It may be adjusted on rod 80 to bring it over different parts of the hearth. It is
provided with an insulated handle 91 of any suitable construction.
A positive conductor 100 is connected at one end with the anode plate 30 and at
the other end with the positive pole of a source of electric current. A conductor 110
is connected at one end to the terminal 70 and at the other end to the negative
service wire or negative pole of the dynamo.
An automatic electrode 90¹ similar to the electrode 90 may be hinged directly
to the terminal 70 and form contact with an article on the hearth. This electrode
is provided with an insulated handle 911 which may be in the form of a rubber
covering.
In the use of this apparatus for heating a horse shoe, the horse shoe placed on
the hearth 40 as indicated in Figures 1 and 4 and the electrode 90 is swung down
into contact with said horse shoe. Then the pump piston 67 is pushed inward and
drives out the contents of the solution contained in the barrel, or a portion thereof,
whereby the level of the solution in the tank 10 is raised to or above the surface of
the hearth 40 and into contact with the shoe or other article resting on the hearth.
The contact of the liquid with the metal closes the circuit and the current passes
from the anode of comparatively large superficial contact with the liquid into the
liquid without incandescence at this point, and then through the liquid to the shoe
or other work which constitutes the cathode or negative pole. Hydrogen is evolved
from the electrolyte or liquid by the electric current and an envelope or film of such
gas immediately forms between the work and the liquid, the latter being apparently
pushed away from the work, and an electric voltaic arc is immediately sprung
between said article and the liquid. The incandescent hydrogen through which the
This arc tends
arc is sprung, reinforces the heating effect of the electric current.
to heat the horse shoe or other article at the desired point and when sufficiently
heated, the pump piston is drawn outward and the liquid lowered, whereby the
current is cut off. The horse shoe may then be removed and forged as desired.
When using the apparatus. for heating a bar or plate of metal this bar or plate may
be laid flat on the hearth in contact with the plain surfaces thereof and arcs will he
sprung only along those parts which are disposed over the grooves in the hearth, so
that a bar or piece of metal may be heated at any desired point or points and other
parts thereof left practically cold being heated only by conduction. Then by
moving the bar, if desired, it may be heated in other parts. In this way the length
or breadth of the part being heated can be regulated by the width of the groove in
the hearth and different given points of the bar may be heated as desired.
When using the apparatus for smelting ores, the ore is placed on the hearth as
illustrated in Figure 2. When the pump piston is pushed inward whereby the
liquid is raised into contact with the ore on the hearth, the circuit is thus closed
and an electric arc sprung between the ore and the liquid and the metals in the ore
are smelted and flow onto the hearth and drop in globules through the holes
therein. These holes facilitate the rise of the liquid into contact with the material
on the hearth. The grooves in the hearth permit the liquid to coine into contact
with the underside of the ore or metal and afford facilities for the springing of an
arc underneath such article or material. It is not desired that the solution shall

page_text: totally submerge the article or ore, but that the total area of the article should be
wet in the solution, and this can be effected by raising the level of the liquid
above the entire article or material to be heated and then lowering it so that
the liquid comes in contact with only a portion thereof leaving the top portion
exposed.
The bath may be used at the same time or separately for heating an article held
in a holder or tongs 120 which rest on the terminal 70 and support the article to be
heated in the solution near the surface thereof.
When a bar or piece of metal is laid on the hearth and the solution is elevated
to the working point, arcs are formed under the bar along those parts which
are disposed over the grooves. By moving the bar different parts thereof can be
heated. Any particular part or parts desired are heated by placing that part or
those parts over the groove or grooves.
The serpentine anode having a large surface exposed to the solution, acts as a
cushion for the current when the circuit is made or broken, since portions of the
current will pass through the spaces between the poles of the plates.
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. In an electrolytic heating apparatus the combination of a vessel for containing
an electrolytic solution, a hearth for supporting the material to be heated provided
with perforations, and electric conductors for connecting said solution and material
with opposite electric poles.
2. In an electrolytic heating apparatus, the combination of a vessel for containing
an electrolytic solution, a perforated hearth for supporting the material to be
heated provided with grooves on its upper face, and means for establishing an
electric arc between the solution and the material on the hearth.
3. In an electrolytic heating apparatus, the combination of a vessel for containing
an electrolytic solution, a hearth for supporting material to be heated, provided
on its upper face with grooves, and intermediate plain surfaces, and means for
establishing an electric arc between the solution and the material on the hearth.
4. In an electrolytic heating apparatus, the combination of a vessel for containing
an electrolytic solution, a hearth for supporting the work to be heated provided
with perforations, a bed for supporting said hearth provided with openings for the
inflow of liquid under said hearth, means for depressing and elevating said solution
in relation to said hearth, and electric conductors for connecting the work and
solution with opposite electric poles.
5. In an electrolytic heating apparatus, the combination of a vessel for con-
taining an electrolytic solution, a hearth for supporting the material to be heated,
a pivoted electrode adapted to be swung into contact with the material on said
hearth, means for depressing and elevating said solution in relation to said hearth,
and electric conductors for connecting said solution and electrodes with opposite
electric poles.
6. In an electrolytic heating apparatus, the combination of a vessel for con-
taining an electrolytic solution, a hearth for supporting the material to be heated,
a conductive bar, a hinged electrode in electric connection with said bar and
adapted to be swung into contact with the material on said hearth, means for
depressing and elevating said solution in relation to said hearth, and electric
conductore for connecting said bar and solution with opposite electric poles.
7. In an electrolytic heating apparatus, the combination of a vessel for con-
taining an electrolytic solution, a hearth for supporting the material to be heated,
a conductive bar, an adjustable conductor movable into and out of contact with said
bar, a hinged electrode on said conductor adapted to swing into contact with the
material on said hearth, means for depressing and elevating said solution in relation
to said hearth, and electric conductors for connecting said bar, and solution with
opposite electric poles.

page_text: 8. In an electrolytic heating apparatus, the combination of a vessel for con--
taining an electrolytic solution, a hearth for supporting material to be heated, a.
conductive rest, a conductor, a hinged electrode connected to said conductor and
adapted to be swung into contact with the material on said hearth, another
electrode hinged to said rest and also adapted to be swung into contact with.
material on said bed, means for elevating and depressing the level of the solution.
in relation to said hearth, and electric conductors for connecting said solution and.
material with opposite electric poles.
9. In an electrolytic heating apparatus, the combination of a vessel for con--
taining an electrolytic solution, a hearth for supporting the material to be heated,.
a conductive rest, a slide rod adapted to be moved into and out of contact with said
rest, a hinged electrode on said slide rod adapted to be swung into contact with the
material on said hearth, a hinged electrode supported on said rest and adapted to be.
swung into contact with the material on said bed, and means for elevating and
depressing the level of the solution in relation to said beartb, and electric conductors
for connecting said bar and solution with opposite electric poles.
10. In an electrolytic heating apparatus, the combination of a vessel for con--
taining an electrolytic solution, a hearth for supporting the material to be heated,
means for elevating and depressing the level of the solution in relation to said
hearth, sockets of insulating material inserted in the edge of said vessel, studs.
supported in said sockets, a conductivo rest supported on said studs, and electric
conductors for connecting said solution and rest with opposite electric poles.
11. In an electrolytic heating apparatus the combination of a vessel for con--
taining an electrolytic solution, a hearth for supporting the material to be heated,
means for elevating and depressing the level of the solution in relation to the
hearth, a plurality of electrodes adapted to be swung into contact with the material
on said hearth, electric conductors for connecting and disconnecting said electrodes.
in the same circuit to form a multiple arc current through said material.
12. In an electrolytic heating apparatus the combination of a vessel for con-
taining an electrolytic solution, a hearth for supporting the material to be heated,.
means for elevating and depressing the level of the solution in relation to Baid
hearth, and an anode in said solution in the form of a serpentine plate, a perforated
partition for protecting said plate, and conductors for connecting said anode and
the material with opposite electric poles.
Dated thin 90th der of March 1895
Witnesses:
FRANCES J. BURTON.
GEO. N. BLISS.
GEORGE DEXTER BURTON.