Improved Methods of Effecting the Electro Fusion of Metals, and in Apparatus therefor.
Year: 1894

page_text: Date of Application, 13th Nov., 1894
Complete Specification Left, 13th Aug., 1895-Accepted, 12th Oct., 1895
PROVISIONAL SPECIFICATION.
Improved Methods of Effecting the Electro Fusion of Metals, and in
Apparatus therefor.
BENJAMIN HOWARTH THWAITE of 95 and 97 Finsbury Pavement London and
HORACE ALLEN, of 95 and 97 Finsbury Pavement London Chemist and Metal-
lurgist do hereby declare the nature of this invention to be as follows:-
This invention relates principally to improvements in a former invention
No. 6000 and dated March 21st 1893 granted to one of the parties to this said
invention and which has for its aim the fusion of steel electrically and in a reducing
atmosphere. We take any ordinary crucible of clay or plumbago or a combination
of same; in this crucible we centrally suspend a funnel shaped feed vessel having
an open bottom which when fed with metallic materials and lifted a little from the
said bottom of the crucible forms a cone shaped accumulation of the metallic
materials that fall from the mouth of the funnel feed. Our manner of electric
application is as follows, we provide attached to the upper part of this central feed
vessel an automatic electric carbon feed arrangement preferably such as that
employed in the Brush electric are lamps, by which one or a series of carbon
pencils forming the terminal of the electric conductor, are constantly fed with
electric energy, which is led to the lower edges of the central feed vessel by which
electric arcs are formed between the metallic materials and the carbons.
prefer to use 2, 4, 6, or more positive carbons fixed on each side of the vessel,
providing as many distinctive currents and arcs in the tranversal of the energy
through the metallic accumulation, as there are carbons. The negative conductor
is formed by the introduction of a copper, or other suitable metallic ring, forming
an inner lining of the funnel feed vessel. The current flows through the metallic
materials forming a connection between the carbons and metallic ring.
We
In order to establish a reducing atmosphere we connect the feeding vessel,
which said vessel may have a tightly fitting feed door, to a reducing gas supply,
the reducing gas permeates through the materials in the feeding funnel and
establishes in the lower part of the crucible a decidedly reducing condition and
this prevents the oxidation of the fused metal or the formation of slag.
The carbons are so arranged that an are may be formed and maintained during
the melting of the charge.
In proportion as the metallic materials are fused melted and collect in the
bottom of the crucible, the feeding funnel vessel with its carbons, is gradually
raised or lifted automatically by a counterbalancing arrangement or by hand, as
most convenient.
By our invention it will be seen that we are enabled to establish a continuous
series of arcs, surrounding the funnel feed and effecting the rapid fusion of the
metallic materials as they leave the funnel mouth and without such action pro-
ducing the formation of slag owing to the reducing atmosphere in which the
electro fusion is effected.
Another modification of our invention is as follows:-As before we provide a
central hollow funnel or cylindrical feed of fireclay or other refractory material,—
on the inside of such feed are arranged the positive carbons and on the outside
of such funnel feed we arrauge the negative carbons-the two carbons being

page_text: separated by the refractory side of the funnel feed. Both the inside and outside
carbons project below the lower edge of the funnel feed, the outer carbons
projecting to a lower level than the inner ones-so that an arc is produced
between the carbons and the metallic materials-which are therefore rapidly
fused and as the metal accumulates the funnel feed with its carbons is gradually
raised; instead of employing two sets of carbons the crucible may be made of
plumbago which may be arranged to constitute the negative terminals; the
current radially flowing from the carbons suspended with the central feed to the
side of the plumbago crucible; by making the feed sufficiently large-that its
carbons are brought at their points to a sufficient nearness to the crucible side,
an arc can be set up and maintained and rapidly fuses the metal.
The conductor wires connected to the carbons, are well insulated and wrapped
with asbestos and the gas connection for establishing a reducing atmosphere is
also of a flexible character.
Dated this 12th day of November 1901
B. H. THWAITE.
HORACE ALLEN.
Improved Methods of Effecting the Electro Fusion of Metals, and in
Apparatus therefor.
We BENJAMIN HOWARTH THWAITE of 95 and 97 Finsbury Pavement London
and HORACE ALLEN Chemist and Metallurgist of 95 and 97 Finsbury Pavement
London 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 relates principally to improvements in a former invention
No. 6000 and dated March 21st, 1893, granted to one of the parties to this said
invention and which has for its aim the fusion of steel electrically and in a reducing
atmosphere. We take any ordinary crucible of clay or plumbago or a combination
of same. In this crucible we centrally suspend a funnel shaped feed vessel having
an open bottom which when fed with metallic materials and lifted a little from the
said bottom of the crucible forms a cone shaped accumulation of the metallic
materials that fall from the mouth of the funnel feed. Our manner of electric
application is as follows, we provide, attached to the upper part of this central feed
vessel, an autoniatic electric carbon feed arrangement preferably such as that
employed in the Brush electric arc lamps, by which one or a series of carbon
pencils forming the terminals of the electric conductor, are constantly fed with
electric energy, which is led to the lower edges of the central feed vessel by which
electric arcs are formed between the metallic materials and the carbons.
prefer to use 2, 4, 6, or more positive carbons fixed on each side of the vessel,
providing as many distinctive currents and arcs in the transmission of the energy
through the metallic accumulation, as there are carbons. The negative conductor
is formed by the introduction of a copper, or other suitable metallic ring forming
an inner lining of the funnel feed vessel. The current flows through the metallic
materials forming a connection between the carbons and metallic ring.
We
In order to establish a reducing atmosphere we connect the feeding vessel (which
said vessel may have a tightly fitting feed door), to a reducing gas supply, the
reducing gas permeates through the materials in the feeding funnel, and establishes
in the lower part of the crucible a decidedly reducing condition and this prevents
the oxidation of the fused metal or the formation of slag. The carbons are
so arranged that an are may be formed and maintained during the melting of
the charge.

page_text: In proportion as the metallic materials are fused melted and collect in the
bottom of the crucible, the feeding funnel vessel with its carbons, is gradually
raised or lifted automatically by a counterbalancing arrangement or by hand, as
most convenient. By our invention it will be seen that we are enabled to establish
a continuous series of arcs, surrounding the funnel feed and effecting the rapid
fusion of the metallic materials as they leave the funnel mouth and without such
action producing the formation of slag owing to the reducing atmosphere in which
the electric fusion is effected. Another modification of our invention is as
follows: As before we provide a central hollow funnel or cylindrical feed of
fireclay or other refractory material. On the inside of such feed are arranged the
positive carbons and on the outside of such funuel feed we arrange the negative
carbons the two carbons being separated by the refractory side of the funnel feed.
Both the inside and outside carbons project below the lower edge of the funnel
feed, the outer carbons projecting to a lower level than the inner ones so that an
arc is produced between the carbons and the metallic materials which are therefore
rapidly fused and as the metal accumulates the funnel feed with its carbons is
gradually raised.
Instead of employing two sets of carbons the crucible may be
made of plumbago which may be arranged to constitute the negative terminals, the
current radially flowing from the carbons suspended with the central feed to the
side of the plumbago crucible. By making the feed sufficiently large-that its
carbons are brought at their points to a sufficient nearness to the crucible side, an
arc can be set up and maintained and rapidly fuses the metal.
The conductor wires connected to the carbons, are well insulated and wrapped
with asbestos and the gas connection for establishing a reducing atmosphere is also
of a flexible character.
Before referring to the sheets of drawings that accompany and are intended
to form part of this Specification, we wish it to be clearly understood that we do
not wish to be confined to the exact details therein shewn as these may be modified
without departing from the nature of our said invention.
Referring to Sheet 1, of drawings, Figure 1. is a vertical section of one
arrangement of our invention and which we generally prefer to adopt. A. is the
fireclay or plumbago crucible containing the metal B, part of which at C, is shewn
to be in a fused or melted condition. The refractory funnel D. contains in the
ceutre the large carbon terminal E. held centrally in position by the guide bars F,
these guide bars are attached to a cap G. that holds the refractory or fireclay tube
or funnel D, in a more or less rigid and central position. This funnel dips into
the mass of metallic material confining the are more or less to the centre of the
crucible and preventing the current from short circuiting to the negative terminals
at H. These terminals consist of a strip or strips of conducting metal that rest
on the inner side of the upper part of the crucible, and having as many conductor
attachments as there are strips of metal. The strips of metal have loose terminal
attachments as shewn, so that if they become partly fused they can be rapidly
detached.
The central carbon E. is held by the slotted sheath J. which is slotted and is
surmounted by the wooden or other non conducting handle K. The central carbon
can be raised or lowered as desired through the cap G. The slotted sheath owing
to its springy character provides a sufficiently tight fit into the cap to carry tho
central carbon and refractory funnel, whilst at the same time permitting the
adjustment of the carbon, which becomes shortened by the action of fusion
influence. This manual adjustment is preferable in many instances to the use of
an automatic arrangement. When we employ the automatic gear we combine our
invention with the use of an arrangement similar to that employed by the Brush
electric light system.
In order to facilitate the removal of the negative and positive terminal arrange-
ments during the charging or pouring arrangements, we provide a suspension gear
comprising a pulley and counter-balance-weight arrangement and a hanging chain,
by the pull of which the entire electric gear can be lifted above the crucible.

page_text: This arrangement is shewn more clearly by Figures 2, 3, and 4, on Sheet 2 of
drawings.
These Figures 2 and 3 illustrate a longitudinal section and a plan in section of a
multiple arrangement of crucibles and their electro fusion gear combined with a
gas or other fuel fired furnace for maintaining the bottom of the crucibles at
a fairly high temperature. Figure 4 illustrates the suspension method of removing
the electro fusion gear.
It will be noticed that the crucibles A. rest on a tiled or brick hearth L. forming
the bottom of a combustion chamber M. The top of the chamber is covered by
tiles N. rebated as shown and having circular openings for the reception of the
crucibles A.
The electro fusion gear is suspended by a counter-balancing arrangement
comprising a couple of pulleys O. and a counterbalancing weight P.
There is a certain slackness in the suspension asbestos ropes Q. that allows the
carbons to be lowered or raised, the upper ropes R. are always in tension so that
the fusion gear can be rapidly lifted away from the crucible during pouring
operations.
By this method of suspending the electric gear, the latter can be entirely
removed from the crucible, enabling the operator to conveniently handle the crucible
for pouring or for charging.
In order to maintain a reducing atmosphere in the crucible during the electro-
fusion operation, we provide a supply of combustible gas, preferably town or
producer gaseous fuel.
We introduce this supply of combustible gas by means of a flexible asbestos
wrapped hose or tubing, the gas is introduced into the interior of the central
refractory cylinder or funnel by the tube S (see Figure 1. Sheet of drawings).
This gas descends to the mouth or lower end of the refractory cylinder and then
forces its way through the metallic materials and escapes and may burn above the
metal in the crucible.
We may provide a supply of air to this gas so that its combustion may be
effected immediately above the metal in the crucible. The heat resulting from
this gaseous combustion added to the influence of a flame surrounding the base of
the crucible prevents the chilling and solidification of the fused metal; until such
time as it is decided to pour. The gas for heating the bottom and lower sides of
the crucibles is led to the gas and air mixing chamber T. see Figures 2 & 3 Sheet 2
of drawings by means of the pipe U. The air enters the mixing chamber T. by
the pipe V. The air is forced into the combustion chamber by means of a fan.
The flame flows along the combustion chamber M. completely enveloping the
base of the crucibles.
The gaseous products of combustion finally escape by the chimney ✗.
The electrical suspension device maintains the gear above a point where it might
be damaged by heat or otherwise and it permits the electrical gear to be rapidly
lifted above the crucible during charging or pouring operations.
Figures 5 and 6 on Sheet 3 of drawings illustrate another modification of our
invention. In this arrangement, the metallic materials to be fused, are introduced
into a central refractory funnel or cylinder 3.
We place a number of carbons 2, at equal distances around this funnel 3, keeping
them in a definite position by means of a ring 4, of good conductor metal, which
serves to collect and distribute the electric energy to the various carbons. These
carbons have their lower terminations about level on the lower opening or mouth
of the central funnel or cylinder.
The metallic materials 5. fed into the central refractory funnel or cylinder form
a conical base, the sides of the central funnel provide a distance arrangement, by
which a series of ares can be established all round the refractory funnel 3.
This
The electric energy crosses from the carbons 2. to the sides and bottom of the
crucible 6. where it is collected by a ring of suitable conducting metal 7.
ring 7 is made to sit on the top lip 8-or edges of the crucible 6.

page_text: Having now particularly ascertained and described the nature of our said inven-
tion and in what manner the same may be performed we declare that what we
claim is included in the following statement of claims.
First. The electro fusion of metals in a crucible in the manner substantially as
shewn in figures and as herein described, and in which the electric energy current
in its circuit flows to or from the centre to the side of the fusion crucible or other
vessel.
Second. The method of applying the production of voltaic arcs in the centre of
a crucible containing metals to be fused for the purpose and substantially as herein
shewn and described.
Third. The employment of a refractory central funnel or cylinder having in its
centre, a carbon conductor or conductors.
Such carbon conductor having its terminal just above, or level with the lower
mouth of such central funnel or cylinder, by which the electric current cannot
short circuit to the sides of the crucible but is compelled to traverse part of the
metallic contents of the crucible.
Fourth. The employment of an adjustable arrangement of carbon by which
either manually or automatically the central carbon conductor or conductors can
be lowered or raised exactly as required.
Fifth. The arrangement of central refractory feed by which the metals to be
fused are fed into the centre of the refractory funnel, and the carbon electric
conductors are disposed uniformly around the outside of such funnel, and the
method of collecting the negative and positive electric energy currents substantially
as herein shewn and described in figures.
Sixth. The method of suspending the electro fusion gear so that it can be
rapidly removed from the crucible during the charging or the pouring of the metal.
Seventh. The method of establishing a reducing atmosphere in and around the
zone of electro fusion in combination with the method and apparatus for effecting
the electro fusion of metals substantially as shewn and described.
Eighth. The method of utilising detachable strips of metal for conductors so
that the latter can be rapidly replaced.
Ninth. The method in its application to the apparatus to and for the purpose
described of wrapping the conductors and gas supply pipes with asbestos.
Dated this 12th day of August 1895.
B. H. THWAITE.
HORACE ALLEN.