Improvements in Furnaces for the Manufacture of Calcium Carbide or the like.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Furnaces for the Manufacture of Calcium Carbide
or the like.
I, TREVOR KEENE, of 9, Elgin Drive, Seabank Road, Liscard, near Birkenhead, in
the County of Chester, Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention has reference to furnaces for the continuous production of calcium
carbide or the like, and more particularly to electrical furnaces for this purpose, in
which the electrical energy is only used to complete the process, the charge being
heated to as high a temperature as possible in the upper part of the furnace before
reaching the electric arc, by waste or other heat.
The furnace is preferably arranged vertically or approximately so, the electrodes
being near the bottom, and it comprises an inner refractory chamber in which the
reaction takes place, and a surrounding outer refractory casing provided with a
charging opening and surmounted by a chimney.
The inner chamber is made in the form of a number of truncated cones placed one
above another, with their smaller diameters downwards, the smaller end of each cone
being preferably connected to the larger end of the cone next below it by a flat or
curved perforated wall.
This arrangement offers several advantages;-in the first place, while the charge
can descend as the action proceeds, its weight is in part supported by the sloping sides
of the cones, so that the pressure at the electrodes is considerably relieved; and in
the second place, the products of combustion and other gases liberated from the
charge can readily escape into the outer casing, through the perforated walls already
described. The said gases, some of which are combustible, impinge upon the outsides
of the cones, and serve to heat the upper portions of the charge to very high
temperature, so that the electrical energy is largely economised. This action may
be supplemented by the aid of gaseous or other fuel introduced within the outer
casing or directly into the charge.
I further provide a hollow stem of refractory material in the centre of the furnace,
extending down towards the bottom of the charge. The walls of this stem may be
perforated so as to serve as passages for the liberated gases, or they may be used to
introduce combustible gases into the charge for the purpose of heating the latter.
The stem is suitably guided and provided with means for rotating and moving it
vertically, so that it is adapted to disturb the charge and aid its descent. It may also
be provided with a projecting spiral flange, so as to partially support and more
efficiently to regulate the descent of the charge.
The bottom of the furnace and the electrodes may be made movable and provided
with means for giving them a reciprocating motion while the furnace is in
operation.

page_text: Improvements in Furnaces for the Manufacture of Calcium Carbide
or the like.
I, TREVOR KEENE, of 9, Elgin Drive, Seabank Road, Liscard, near Birkenhead, in
the County of Chester, Engineer, do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention has reference to furnaces for the continuous production of calcium
carbide or the like, and more particularly to electrical furnaces for this purpose, in
which the electrical energy is only used to complete the process, the charge being
heated to as high a temperature as possible in the upper part of the furnace before
reaching the electric arc, by waste or other heat.
I have illustrated my invention in the accompanying drawings, in which Fig. I is
an elevation in section on the line A. A. of Fig. II; Fig. II a plan in section on the
line B. B. of Fig. I; Fig. III an elevation in section on the line C. C. of Fig. IV,
which line is at right angles to A. A. of Fig. II; and Fig. IV is a plan in section on
the line D. D. of Fig. III. Throughout the drawings the same parts are indicated by
the same reference figures, and the direction in which the sections are viewed
is indicated by the small arrows placed adjacent to the letters denoting the plane of
section.
The furnace is preferably arranged vertically or approximately so, the electrodes 1
being near the bottom, and it comprises an inner refractory chamber 2 in which the
reaction takes place, and a surrounding outer refractory casing 3 provided with
charging openings 4 and 5 and surmounted by a chimney 6.
The inner chamber 2 is made in the form of a number of truncated cones placed
one above another, with their smaller diameters downwards, the smaller end of each
cone being preferably connected to the larger end of the cone next below it by a flat
or curved perforated wall such as 7.
This arrangement offers several advantages:-in the first place, while the charge
can descend as the action proceeds, its weight is in part supported by the
sloping sides of the cones, so that the pressure at the electrodes is considerably
relieved; and in the second place, the products of combustion and other gases
liberated from the charge can readily escape into the outer casing, through holes 8 in
the perforated walls 7. The said gases, some of which are combustible, impinge upon
the outsides of the cones, and serve to heat the upper portions of the charge to very
high temperature, so that the electrical energy is largely economised. This action
may be supplemented by the aid of gaseous or other fuel introduced within the outer
casing or directly into the charge.
I further provide a hollow stem 9 of refractory material in the centre of the
furnace, extending down towards the bottom of the charge. The walls of this stem
may be perforated by holes 10 which serve as passages for the liberated gases, or
they may be used to introduce combustible gases into the charge for the purpose of
heating the latter. The stem is suitably guided at 11 and 12 and is provided with
means for rotating and moving it vertically, so that it is adapted to disturb the charge
and aid its descent. It may also be provided with a projecting spiral flange, so as to
partially support and more efficiently to regulate the descent of the charge.
The means for rotating the stem 9 and moving it vertically are not shown, as any
of the usual and well known forms of mechanism adapted to give such movements
may be adopted; the chimney 6 is deflected laterally so as to allow the prolongation
of the stem 9 to pass out of the furnace at 12, by which arrangement the mechanism

page_text: for giving the stem the desired movement may be effectually protected from the
destructive action of the heat of the furnace.
The electrodes 1 are shown as sloping downwards into the furnace; by arranging
them in this way they are less likely to be affected by the pressure of the superin-
cumbent material in the furnace, and can therefore be fed with greater ease
and regularity. The means for feeding the electrodes to maintain the arc are, of
course, not shown as any of the well known devices may be used for this purpose.
As already mentioned the action of the furnace may be supplemented by gaseous
fuel introduced either into the outer casing 3 through suitable openings such as 13,
or into the inner chamber 2 through the hollow stem 9.
The coke, which in most furnaces of this type is introduced with the lime at or
near the top of the furnace may, according to my invention, be separately introduced
through the lower charging holes 5, the lime being introduced through the upper
charging holes 4; but, of course, if desired both may be introduced at 4, although it
is found best to introduce the coke at the lower openings so that it may reach this
part of the furnace before being consumed..
The inner chamber is strengthened by radial ribs 14 which connect the sloping
sides of the cones to the walls 7; these ribs are shown in plan in Fig. II and the
perforations 8 are spaced between the ribs.
A tunnel 15 is provided under the furnace through which the carbide is led away
from the outlet 16.
The bottom of the furnace and the electrodes may be made movable and provided
with means for giving them a reciprocating motion while the furnace is in operation.
The action of the furnace is as follows:-
The lime and coke having been supplied as described in the required proportions
for, say, the production of calcium carbide, the operation is commenced either by
striking the arc across the electrodes, or by initially heating the inner chamber by
the introduction of combustible gases through the openings 13, or through the
stem 9, the said gases being suitably ignited. As the action proceeds the gases
liberated by the chemical reaction which takes place, some of which are combustible,
pass up through the openings 8 and impinge against the sloping sides of the cones
and so heat the inner chamber; when the stem 9 is not used to introduce combustible
gases the openings 10 in it serve to diffuse the liberated gases which enter by the
lower openings and leave by the upper ones.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The improved furnace for the manufacture of calcium carbide or the like, which
consists of an outer casing and an inner chamber formed by a series of truncated
cones united by perforated walls and placed above the electrodes, the sloping sides of
the inner chamber being adapted to partially support the weight of the material acted
upon and so relieve the pressure at the electrodes; substantially as described.
2. The improved furnace for the manufacture of calcium carbide or the like, which
consists of an outer casing; an inner chamber formed by a series of truncated cones
united by perforated walls and adapted to partially support the weight of the materials
acted upon and so relieve the pressure at the electrodes; and a hollow perforated stem
adapted to be rotated and moved vertically to assist the descent of the said materials;
substantially as described.
3. In a furnace for the manufacture of carbide or the like, in combination ;
the outer casing; the inner casing formed of truncated cones; the movable. hollow
stem;
the upper and lower charging openings; the electrodes; and the openings 8
and 10 adapted to diffuse the gases; substantially as described and illustrated.
4. In furnaces of the kind herein described, the use of an inner chamber consisting
of a series of truncated cones united by walls so perforated that the gases released at
one part of the furnace pass through the said perforations and externally heat the
sloping surface above; substantially as described and illustrated.

page_text: 5. The combination and arrangement of parts forming the improved furnace for
the manufacture of calcium carbide or the like, substantially as described and
illustrated.
Dated this 19th day of January 1808
SLOAN & LLOYD BARNES,
Castle Chambers, 26, Castle Street, Liverpool, Agents for the Applicant.