Improvements in and relating to Electrical Furnaces, specially applicable for the Production of Calcium Carbide.
Year: 1897

page_text: Improvements in and relating to Electrical Furnaces, specially
applicable for the Production of Calcium Carbide.
We, GEORGE WILLIAM BENJAMIN CREES, of Wingfield, Trowbridge, in the
County of Wilts, Engineer, WILLIAM LANG DURBAN, of 79, Ashton Street, Trow-
bridge, aforesaid, Chemist, and JOHN GORE, of Crandon Villa, Trowbridge, afore-
said, Engineer, do hereby declare the nature of this invention to be as follows:-
:-
In electrical furnaces as hitherto constructed for the treatment of oxides, such
as are used in the production of carbides or for other purposes, it has been cus-
tomary in some cases to employ two electrodes situated oppositely within the
walls of the furnace, the electrodes being connected by a carbon rod or equiva-
lent, which on becoming heated to incandescence, imparts an intense heat to
the mixture or substance contained in the furnace, thereby reducing the oxide
and producing, for example, a chemical combination of the carbon with the re-
maining ingredient, resulting in a carbide. An objection to a furnace of this
class is that the mixture as it becomes fused and converted say into carbide con-
solidates into a mass of close density and consequently falls away from the elec-
trodes (or one of them) cutting off the electric current to a greater or less extent.
Now, by our invention, we construct a furnace in which the electrodes shall
extend to the bottom or nearly to the bottom thereof, and may themselves form
two opposite ends of the furnace. We also arrange the electrodes so that they
are capable of approaching or receding from each other, and are preferably con-
trolled by a spring or springs, tending to force them inwards, towards the centre of
the furnace, so that the carbon rod or equivalent on being placed between them
may hold them apart and remain supported at its ends by the pressure. Instead
of a spring, we may employ a screw, or weighted lever, or other equivalent
device. The advantage of causing the electrodes to extend to the bottom or
nearly to the bottom of the furnace is that the mass under treatment may during
the full period of time up to completion of the operation, always be in the elec-
tric circuit and in contact with the electrodes, notwithstanding that the mass may
have fallen to a lower level in the furnace. A further advantage of causing the
ends to bear towards one another is that the lower portion of the charge, which
is the last to succumb to the intense heat (being furthest away from the source
of heat) will in certain conditions be raised up, and a comparatively large mass
will thus become converted at each operation.
Dated this 17th day of November 1897
STANLEY, POPPLEWELL & Co.,
Chartered Patent Agents, 61, Chancery Lane, London, W.C.,
Agents for the Applicants.

page_text: Infprovements in and relating to Electrical Furnaces, specially
applicable for the Production of Calcium Carbide.
We, GEORGE WILLIAM BENJAMIN CREES, of Wingfield, Trowbridge, in the
County of Wilts, Engineer, WILLIAM LANG DURBAN, of 79, Ashton Street, Trow-
bridge aforesaid, Chemist, and JoHN GORE, of Crandon Villa, Trowbridge afore-
said, 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:--
In electrical furnaces as hitherto constructed for the treatment of oxides, such
as are used in the production of carbides or for other purposes, it has been cus-
tomary in some cases to employ two electrodes situated oppositely within the
walls of the furnace, the electrodes being connected by a carbon rod or equiva-
lent, which on becoming heated to incandescence imparts an intense heat to
the mixture or substance contained in the furnace, thereby reducing the oxide
and producing, for example, a chemical combination of the carbon with the re-
maining ingredient, resulting in a carbide. An objection to a furnace of this
class is that the mixture as it becomes fused and converted say, into carbide, con-
solidates into a mass of close density and consequently falls down away from the
electrodes (or one of them) cutting off the electric current to a greater or less
extent.
Now, by our invention, we construct a furnace in which the electrodes shall
extend to the bottom or nearly to the bottom thereof, and may themselves form
two opposite ends of the furnace. We also arrange the electrodes so that they
are capable of approaching or receding from each other, and are preferably con-
trolled by a screw or screws, tending to force them inwards, when desired, to-
wards the centre of the furnace, so that the carbon rod or equivalent on being
placed between them may remain supported at its ends by the pressure. Instead
of a screw, we may employ a spring, or weighted lever, or other equivalent
device. The advantage of causing the electrodes to extend to the bottom or
nearly to the bottom of the furnace is that the mass under treatment may during
the full period of time up to completion of the operation, always be in the elec-
tric circuit and in contact with the electrodes, notwithstanding that the mass may
have fallen to a lower level in the furnace. A further advantage of causing the
ends to approach or bear towards one another is that the lower portion of the charge
which is the last to succumb to the intense heat (being furthest away from the source
of heat) will in certain conditions be raised up, and brought within the path of
the powerful electric current. A comparatively large mass will thus become con-
verted at each operation.
Upon the accompanying sheet of drawings is illustrated one manner of carrying
out our improvements, which we find to work well in practice, Figure 1 being a
sectional elevation and Figure 2 a perspective view of the furnace constructed
and arranged according to our invention.
Referring to the accompanying drawings, A is a thick slab of firebrick or other
durable substance forming the bottom of the furnace, the sides BB being of the
same or similar material. The latter may be held rigidly upright by means of
tie bolts and nuts B' B₁ as shown. The other two sides or ends CC form the
electrodes between which the electric current passes or alternates and are there-
fore made preferably of carbon plates built together to a considerable thickness,
and are supported in upright position by a pair of screwed rods D D, each one of
which is attached rigidly and firmly to one of the plates CC and projects out-

page_text: wardly at right angles, resting in bearings EEE¹ E¹. The method of connecting
the rods DD with the plates CC may be by means of four copper or other
metallic arms RRRR bent at their extremities so as to grip the edges of the
plate Cand radiating from a central metallic boss R¹ into which the rod D is
secured in any suitable and well known manner. The cables are connected up
to the electrodes by the metallic loops 00 in contact with the uppermost arms K,
the four radiating arms serving as a means for distributing the current over the
area of the electrode.
The rods D need not be screwed throughout and both the bearings E and E¹
are plain bearings. The outer bearing E, however, to which point the screwed por-
tion of the rod D must always extend, does not receive the rod direct, but acts
as a bearing for a hollow spindle F internally threaded to correspond with the
thread on the rod D. Said spindle F is kept in position by means of a flange G
on the one side and a handwheel or handle H or the other side. The rod D
passes normally through the hollow threaded spindle F, and a turn of the hand-
wheels HH in either direction causes a horizontal movement of the plates CC
further into or out of the furnace. The carbon rod N, which is employed for
producing the initial heat within the furnace by its incandescence, is held in posi-
tion by turning the handwheel or hand wheels until the two plates CC have
approached so near to each other as to firmly press upon the ends of the rod
separating them. The furnace may be built upon masonry M composed of fire-
bricks.
We may provide a slide within the floor of our furnace, so that during working,
when a certain mass or nugget of calcium carbide has been produced, the said
slide may be withdrawn, and the loose carbon and lime at the bottom of the
furnace, hitherto outside the zone of maximum heat necessary for its reduction,
may be allowed to fall out into a vessel and be again fed into the. furnace at the
top.
It will be understood that, without departing from the spirit of our invention,
we may cause the electrodes to be embedded within or form part of the movable
ends CC, instead of composing said ends entirely of electrical conducting mate-
rial, as herein before set forth.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is;-
An electric furnace in which two opposite sides or ends contain or themselves
constitute the two opposite electrodes, said sides or ends being mounted upon
screwed rods each suitably provided with a handwheel or equivalent means
whereby they may be brought nearer to or further away from one another sub-
stantially as and for the purpose specified and as shown by the accompanying
drawings.
STANLEY, POPPLEWELL & Co.,
61 & 62, Chancery Lane (7 & 8, Southampton Buildings), London, W.C.,
Chartered Patent Agents.