Improved Method and Apparatus for Producing Calcium Carbide.
Year: 1898

page_text: Date of Application, 29th Mar., 1898-Accepted, 28th May, 1898
Improved Method and Apparatus for Producing Calcium Carbide.
communication by CORYDON L. WILSON, CHARLES MUMA, JOHN W. UNGER,
HENRY SCHNECKLOTH, AMOS P. BROSIUS, and JOSEPH C. KUCHEL, all of Holstein,
in the County of Ida and State of Iowa, United States of America.
I, 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, 118, New Street, Birmingham, in the County of Warwick,
and 322, 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 relates to that process of producing calcium carbide, in which a
mixture of lime and carbon is subjected to the heat of an electric arc.
Heretofore this process has usually been practised by causing a mixture of lime
and carbon to be placed between and around adjacent ends of two electrodes, and then
causing a current of electricity to pass through the electrodes to form an arc between
them, to thereby melt the mixture, and then causing said electrodes, or one of them,
to be gradually withdrawn, as the mixture becomes a molten mass, to thereby admit
more of the mixture and thus reduce only a portion of the entire mixture to a liquid
state. By the use of this process it has been found practically impossible to bring
all of the mixture directly within the arc, hence part of it must be melted, if melted
at all, by contact with the molten mass. It has been found further in practising this
process that all of the mixture is not melted but part of it is inextricably embedded
in the finished product and by its presence reduces the value and efficiency of the
product.
A further difficulty has been encountered in practising this process, in that the
molten product will adhere with great tenacity to the receptacle in which it is
melted.
Its object is first, to provide a process for reducing lime and carbon, in the practice
of which process, lime and carbon are fed to the electrodes in a cleanly and
convenient manner.
Its object is further to provide a process for reducing lime and carbon, in the
practice of which process the resultant product is completely, perfectly, and
thoroughly reduced at all times. Thus when the electric current is unavoidably
stopped none of the product is wasted.
A further object is to provide a process of reducing lime and carbon in which
the finished product has no incrustation of unreduced or partly unreduced lime and
carbon, and in which said product will not adhere to the receptacle in which it is
reduced.
A further object is to provide a process for reducing lime and carbon, in the
practice of which the full power of the electric current may be utilized at all times.
A further object is to provide an electric furnace of this class in which the
substance to be reduced will not pass beyond the arc until it has been melted
by the heat of the arc, to thereby prevent the passage of any amount of unreduced
lime and carbon into the receptacle which holds the finished product.

page_text: A further object is to provide an improved apparatus for producing calcium
carbide.
The invention consists in the arrangement, and combination with each other of
the relative steps in the reduction of lime and carbon, to the finished product of
calcium carbide, and further in the construction, arrangement and combination
of the various parts of the device, as hereinafter set forth, pointed out in the claims,
and illustrated in the accompanying drawings, in which :-
Figure 1 shows a vertical sectional view of the apparatus whereby the process may
be conducted.
Figure 2 shows a top or plan view of the same apparatus.
Figure 3 shows a vertical sectional view of a modified form of apparatus by which
the process may be practised.
Figure 4 shows a top or plan view of the same.
Figure 5 shows a vertical sectional view of another modified form of apparatus
whereby this process may be practised.
Figure 6 shows a vertical sectional view of another form of apparatus by which the
same process may be conducted.
Figure 7 shows a vertical sectional view of still another modification by which
the same process may be practised.
Figure 8 shows a longitudinal sectional view of a number of pieces of lime and
carbon compressed into elongated blocks and contained within a tubular wrapper.
Referring to the accompanying drawings, the construction shown in Figures 1 and 2
and embodying the preferred form of apparatus with which the process may be
carried on shall be first set forth. The reference numeral 10 is used to indicate a
base having a bowl shaped central opening 11, from which a duct 12, leads to a
discharge point exterior to the base.
The reference numerals 13 are used to indicate two tubes or sleeves extended in
an approximately horizontal position through the walls of the base, with their inner
ends in alignment and adjacent to each other near the central portion of the basin 11.
These tubes or sleeves 13, are made of some material which is a good conductor of
electricity, and fixed to the exterior end of each tube is an electric cable 14, which
cable leads to the source of electrical supply 15.
An arc is struck between the electrodes 13 when a current of electricity is passed
from the dynamo or source of supply 15 to the electrodes. These electrodes may be
moved with relation to each other by the hand wheels 18 in such proximity that
a perfect arc may be produced.
Means are provided for adjusting the electrodes 13 relative to each other as
follows: The reference numeral 16 indicates a bracket fixed to the exterior wall of the
base and having rotatably mounted therein a screw shaft 17 on one end of which a
hand wheel 18 is fixed, and the other end thereof is seated in an arm 19, which in
turn is fixed to the outer end of the electrode. A similar device is applied to each
electrode, hence an operation of the hand wheel 18 will move the electrode in a
horizontal plane relative to the opposite electrode.
is formed by first
same to a pressure
without the use of a
permit hooks, such as
In Figure 8 the reference numeral 20 is applied to the elongated block which is
composed of a mixture of lime and carbon which
pulverizing lime and carbon and then subjecting the
to form it into blocks of this shape. This produces firm sticks
binder. These sticks thus formed are of sufficient strength to
are shown in Figure 5, to be placed in their ends for the purpose of connecting a
series of these blocks. They must, however, be used soon after they have been
compressed into stick form for the reason that the action of the air upon them will
cause them to disintegrate after the manner of "air slacked lime." The reference
numeral 21 indicates a sleeve which may be made of any suitable material such, for
instance, as paste board, asbestos, or sheet metal, and this sleeve is extended from a
point a considerable distance from one end of the block 20, to a point the same
distance beyond the other end of the said block. Thus when a number of the blocks

page_text: e brought together the joints in the blocks and the joints in the casing win not
incide.
In practising this method by use of this apparatus a series of these blocks are com-
ned and two of these series are introduced into the ends of the hollow electrodes 13
A current of electricity
d caused to meet between the ends of the electrodes 13.
then caused to flow through the electrodes and to form an are between their
jacent ends. The intense heat at this place causes the sticks or blocks of lime and
As
arbon, together with the wrappers thereon, to melt and drop into the basin 11.
st as the sticks of lime and carbon are melted away at the inner ends of the
lectrodes, other sticks, each having a sleeve thereon, are inserted in the outer ends
f the electrodes and the sleeve of each is made to overlap the block adjacent thereto.
Ience a substantially continuous supply of lime and carbon is fed to the arc formed
etween the electrodes, and the end of one stick or block of lime and carbon is
revented from falling off into the basin 11, before it has been melted, on account of
he sleeve of the adjacent block or stick supporting it until the sleeve itself is
onsumed.
The apparatus illustrated in Figures 3 and 4 comprise a base, a central opening,
nd a dúct leading therefrom, exactly similar to that of the apparatus just described.
Two electrodes 22 are fixed in the walls of the base in a horizontal plane and in
lignment with each other, with their ends in such proximity as to produce an arc
between them when a current of electricity is passed through them. Sleeves 23 are
Electric cables 24
preferably mounted in these walls to receive the said electrodes.
are fixed direct to the outer ends of the electrodes and lead to the source of electrical
supply 25.
The numeral 26 is used to indicate hollow tubes placed in the walls of the base in
the same horizontal plane as the electrodes 22, but at exactly right angles thereto.
Lime and carbon in stick or block form, preferably as shown in Figure 8, is fed through
these tubes 26 to pass.between the electrodes 22.
In practising this method by the use of this apparatus, an electric arc is first
Then the lime and
established in a well known manner between the electrodes 22.
carbon in stick or block form is forced through one or both of the sleeves 26, until
the end or ends thereof pass between the electrodes or rather through the arc formed
thereby, where it is melted and runs into the basin 11.
The apparatus for practising this process illustrated in Figure 5, is similar to the
provided with
apparatus just previously described except that one of the electrodes
means for adjusting it horizontally as follows:-The numeral 30 indicates a bracket
fixed to the furnace wall, and having a screw shaft 31, rotatably mounted therein and
provided with a hand wheel 32 on its one end and having its other end passing
In this form
through a screw threaded arm 33 which in turn is fixed to the electrode.
Means
there are no tubes through which the lime and carbon are fed to the arc.
have, however, been provided whereby a series of sticks or blocks of lime and carbon
may be connected in such a way that they may be held in a vertical position, with
the lower end of one of the sticks or blocks extending between the electrodes cr
in the arc.
This means comprises blocks 34 made of a mixture of lime and carbon
and compressed into this shape, and also provided with a number of transverse
openings 35, and a number of metallic hooks 36, placed in the ends of said sticks or
blocks whereby the sticks may be connected and held together.
The transverse openings 35 formed in the sticks of lime and carbon provide means
whereby the heat of the electric arc may take effect upon every particle of the lime
) and carbon more rapidly than would be possible if the sticks were solid, and hence a
greater quantity of lime and carbon provided with these openings may be melted in
an are of given intensity, than would be possible if the sticks were solid.
In practising this method by the use of this apparatus the arc is established
between the electrodes in the ordinary way, a series of the blocks 34, are connected
5 together by means of the hooks 36, and the lower end of the lower block is kept
between the electrodes or in the arc, and as fast as it is melted away the blocks are
fed downwardly by gravity so that a portion of the lime and carbon remains between

page_text: the electrodes at all times. The material of which the hooks are formed, is melted as
fast as they are passed between the electrodes and the presence of this slight amount
of metal in the finished calcium carbide is so inconsiderable as not to be noticed.
In the modification shown in Figure 6 the furnace proper is of identical
construction with the furnace shown in Figure 5, hence a repetition of the description
is omitted. Means are, however, provided whereby the lime and carbon may be
fed to the space between the electrodes or the arc, automatically as follows:-
The reference numeral 40 is used to indicate arms or brackets mounted on top of
the furnace wall to support tubes 41 which are placed on an incline approximating
45 degrees, and which have their lower ends extending to the point adjacent to the
space between the electrodes and at right angles thereto. The other ends of the
sleeves may be projected as far as found desirable. The reference numéral 42 is used to
indicate the blocks of lime and carbon compressed as before described, and the
numeral 43 indicates coupling devices having hooked ends 44, one of which is placed
in the end portion of one of the blocks 42, and the other in the end portion of an
adjacent block at the upper edge thereof. Each of the tubes 41 is filled with a series
of the blocks 42, connected by means of the hooks 44 with each other. The lower
ends of the two series of blocks are arranged to meet at a point between the
electrodes or in the arc. It is obvious that, as fast as the lime and carbon of which
these blocks are formed is melted away, the blocks will drop by gravity to replace
the part burned away, but it is also obvious that one of the series of blocks cannot
pass beyond the other, hence there will be always a quantity of the lime and carbon
in the arc. The connecting rods 43 serve to support the ends of the blocks after
they have passed beyond the lower ends of the sleeves. It being impractical to
extend the sleeves very close to the electrodes on account of the intense heat of
the arc tending to consume any material which is placed within its direct influence.
The form of apparatus shown in Figure 7 for carrying out this process comprises a
base 50, having an electrode 51, mounted in its top, a metal casing 52, above the
base, and a tubular electrode 53 supported in a vertical position above the
electrode 51, electric cables 54, leading from the electrodes 51 and 53 to the source of
electrical supply 55. 56 indicates a chute leading to the opening in the hollow
electrode 53. 57 indicates a quantity of calcium carbide in pulverized or granular
form placed on the base and around the sides of the chamber at the top of the base
50.
In practising this process by the use of this apparatus, a mixture of lime and
carbon in granular or pulverized form is placed in the chute 56 to pass through the
electrode 53 and into the space between the electrode or the arc. It is obvious that,
upon the completion of the current, the lime and carbon between the electrodes will
be melted, and will run off into the casing 52, and commingle with the pulverized
calcium carbide 57. When the casing is removed the calcium carbide may be readily
taken from the furnace and broken up into the desired size, it being obvious that
there can be no incrustation on the finished product of crude or imperfectly reduced
lime and carbon. It is obvious further that the molten product will not adhere to the
base or to the casing because of the layer of pulverized calcium carbide which protects
it from the base and casing.
My correspondents are aware that heretofore a method of reducing ores, etcetera,
was practised, in which an electric arc was established, and a mixture of ores in
pulverized or granular form was caused to drop downwardly through the electrode,
and in its passage therethrough was melted or reduced. However, in the practice of
such a method it is obvious that under certain conditions, it is conceivable that the
ores would not be melted thoroughly in their passage through the arc; and further-
more, when the electric current is temporarily cut off, certain portions of the ore
would also pass through without being melted. By feeding the substance to be
melted or reduced into the arc in block or stick form, in which a series of blocks or
sticks are connected, it is readily seen that none of the material may pass beyond the
electrode until it has been melted, and in the event of the current being suddenly
cut off, none of the material will pass beyond the electrode into the receiver, and

page_text: 35
40
ven if the operation of feeding the material should continue a short time after but
lectric current has been discontinued, the material will not be melted, and hence
hen the current is again established the material may be drawn from the arc, and
hen melted upon the re-establishment of the current.
My correspondents do not desire to be understood as limiting themselves to the
se of any one of the apparatuses shown and described inasmuch as the process of
lacing or introducing a mixture of lime and carbon in the electric arc may be
practised by hand or in the use of very simple means.
They have shown and described such apparatus for carrying out their process
as they believe is best adapted for practical use, and the number and variety of the
means shown are thought to be conclusive evidence that the invention cannot be
properly covered by claims on the mechanical construction alone.
They are aware that heretofore electric furnaces for similar uses have been provided
with substances in stick form which have been used as electrodes and the substances
melted and permitted to run from the arc as fast as the electrodes were fed toward
each other, and in such cases there was no possibility of any of the substance to be
reduced passing out of the are until melted. They are also aware that furnaces of
this class have been made heretofore in which an arc was first established by means
of suitable electrodes and then the substances to be melted fed to the arc, but
they are not aware that there has ever been a furnace of this class constructed in
which two electrodes are used, made of suitable material, with the object of
establishing an are between them of a maximum intensity with a minimum of
applied electric current, and then the substance to be melted placed in the arc
between the electrodes and there held until melted.
-
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to
me by my foreign correspondents I declare that what I claim is :-
1. The process of producing calcium carbide which consists in first causing the
base and sides of the furnace or receptacle in which the process is carried on, to be
lined with calcium carbide in granular form, and then causing a mixture of lime and
carbon to be fed into the space between the electrodes or the said arc so that the
molten product may run into the base and sides so covered with calcium carbide.
2. The process of producing calcium carbide which consists in first causing lime
and carbon, or their equivalents to be pulverized, then causing them to be
commingled, then causing the mixture to be compressed into blocks or sticks, then
causing the blocks or sticks to be connected, then causing the furnace or receptacle
in which the calcium carbon is to be melted to be lined with pulverized o
granulated calcium carbide, then causing an electric arc to be established, and
finally causing the sticks or blocks to be fed into the said arc.
3. An apparatus for producing calcium carbide, comprising a furnace, a lining
of calcium carbide loosely arranged within the furnace wall, means for establishing
an electric arc within the furnace and means for feeding lime and carbon int
said arc, for the purposes stated.
March 1898.