An Improved Manufacture of Carbon for Electrical Purposes.
Year: 1893

page_text: Date of Application, 8th July, 1893
Complete Specification Left, 29th Mar., 1894-Accepted, 5th May, 1894
PROVISIONAL SPECIFICATION.
[Communicated from abroad by Adam CHARLES GIRARD, of 7, Rue du Bellay,
Paris, France, Chemist, and ERNEST AUGUSTE GEORGES STREET, of
39, Rue Joubert, Paris, France, Engineer.]
An Improved Manufacture of Carbon for Electrical Purposes.
I, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby declare
the nature of this invention to be as follows:-
Experiments made some time ago by Despretz and Berthelot with the object of
studying the facts relating to the sublimation and fusion of carbon demonstrated
that, at high temperatures, carbon of different kinds passes into the graphitic state.
These experiments have however remained in the region of the laboratory and have
had no industrial application.
Graphitic carbon has not heretofore been manufactured commercially, or
industrially applied.
The present invention has for its objects the manufacture of graphitic carbon, on
a commercial scale, and the application of such carbon to electrical purposes,
notably for lighting, electrolysis, and batteries.
In carrying this invention into practice carbons manufactured in the ordinary
manner for electrical purposes are subjected to such a temperature as will soften,
fuse or sublime the same and finally transform them (either completely or in part)
into graphitic carbon or graphite, and I use the term graphite to indicate that state
of carbon which by Berthelot's method of analysis gives rise to the production of
graphitic oxide. I cannot state the exact temperature to which the carbon is to
be raised for the reason that it is very difficult if not impossible to measure it in
the present state of science. I will however define it in as precise a manner as
possible by stating that it is to be at least equal to that at which carbon softens,
welds, fuses or sublimes.
Carbons which have been submitted to this high temperature possess for
electrical purposes, special properties which differentiate them in a marked degree
from those which are manufactured by the ordinary methods heretofore in use.
With regard to arc-light carbons their conductivity is considerably increased
and their rate of consumption is diminished, and as regards carbons for use in
electrolysis or as battery carbons their conductivity is increased, and they are
moreover considerably less attacked or disorganized by the action of nascent
gases.
Agglomerate carbons are at present made by taking carbon in different forms or
modifications and mixing it with a suitable agglutinant and then subjecting the
mixture to pressure suitable for moulding it or forcing it through a die.
The carbon preferably employed is lamp black or amorphous carbon and gas
retort carbon; this last is improperly called "retort graphite" and is in fact what
I term metallic carbon.
These different kinds of carbon and that resulting from the baking or carbonising
of the agglutinant, which is generally tar, are all brought by the baking process
adopted in the ordinary manufacture of carbon heretofore in use to a state or
condition which does not go beyond that which I have herein called metallic
carbon.
To attain to the graphitic state defined by Berthelot it is necessary as herein-
before stated to raise the temperature of baking to a degree which effects the
softening, welding, fusion or sublimation of the carbon.

page_text: This temperature varies according as the operation is conducted in a total or a
partial vacuum, or under ordinary atmospheric or higher pressures, and in atmos-
pheres of gases such as carbonic oxide, nitrogen, hydrogen, and sulphide of carbon;
but in all cases in order to obtain the total or partial transformation of the carbon
into graphite, it is necessary to heat it to the temperature, (variable according to
the pressure and surroundings) at which the carbon softens, welds, melts, or
sublimes.
This graphitic carbon can be obtained by means of any suitable apparatus
capable of producing the desired temperature; nevertheless I will indicate by way
of example, two methods of procedure.
According to the first method I bring to a state of incandescence the whole mass
which it is required to transform into graphite, by means of an electric current so
that the temperature is raised more or less rapidly and attains to the degree at
which the carbon softens, welds, melts or sublimes.
I may conduct the operation with exposure to the air or in closed vessels
permitting the heat to accumulate or not and allowing of the introduction of
suitable gases or vapours under pressure or not permitting a total or partial vacuum
to be maintained.
According to the second method I bring a part more or less deep of the carbon
which is to be transformed into graphite to the temperature which I have herein-
above defined. In this case the transformation is only partial. I obtain such a
result by subjecting the surface of the carbon to the action of the electric arc, by
moving the are over the whole of the surface as the operation proceeds, or by
moving the carbon, the are remaining stationary.
I thus transform the outer layers of carbon to a greater or less depth and I
condense within the piece undergoing treatment carbon vapours in a manner more
or less complete according to the mean temperature to which the whole of the mass
is subjected. These condensed carbon vapours produce greater or less quantities of
graphite in the interior of the carbon.
To bring to the desired temperature the surfaces of the pieces to be transformed
I can advantageously employ a suitable electric furnace.
Again I can either in the air or in suitable atmospheres of special gases and with
or without pressure conduct the electric arc to the surface of the piece to be trans-
formed by connecting one of the poles of a suitable source of electricity with the
piece to be treated and striking the arc by means of a cylinder or rod of carbon
connected to the other pole of electricity. By moving this carbon rod along the
piece to be treated or by moving the piece to be treated, the arc is brought into
contact with the whole surface of the piece and the outer layers of the piece are
transformed into graphite to a greater or less depth varying with the quickness of
movement given to the carbon rod or to the piece itself and with the intensity of
the current employed.
Again I can raise the surface of the piece to be treated to the suitable
temperature, without the aid of the arc, but by the heat generated on the surface
by the current itself.
For this purpose I connect one of the poles of the source of electricity to the
piece to be treated and the other pole to a piece of carbon of suitable shape. I
place this last piece in contact with the piece to be treated, and, if the current has
an intensity suitable to the shape of the carbon, a temperature suitable for the
transformation will be developed at the point of contact. I can interpose powdered
carbon between the piece to be treated and the carbon electrode, so as to increase
the resistance at the point of contact and facilitate the attainment of the required
temperature. It will be seen that by touching all the parts of the piece to be
treated under the conditions above stated the surface of the piece will be
transformed more or less deeply.
In fact by subjecting the surface of the piece to the temperature above defined I
cover the same with a layer of greater or less thickness of melted or welded
carbon.

page_text: Graphitic carbon thus commercially obtained may be advantageously applied to
electrical engineering for many uses.
I have hereinbefore spoken of the treatment of pieces of carbon having certain
dimensions, but I may apply this treatment to granular or powdered carbon which
may be used in the manufacture of carbon by agglomeration or in telephones and
microphones, or in other ways.
I have herein before described the treatment of carbons which have been first
manufactured in the ordinary manner, but it is obvious that I can treat crude
carbon of any shape or form by first taking precaution to ensure the distillation of
the volatile products contained therein.
Dated this 8th day of July 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Manufacture of Carbon for Electrical Purposes.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45 Southampton Buildings, in the County of Middlesex, 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 :-
Experiments made some time ago by Despretz and Berthelot with the object of
studying the facts relating to the sublimation and fusion of carbon demonstrated that,
at high temperatures, carbon of different kinds passes into the graphitic state.
These experiments have however remained in the region of the laboratory and have
had no industrial application.
Graphitic carbon has not heretofore been manufactured commercially, or
industrially applied.
The present invention has for its objects the manufacture of graphitic carbon, on
a commercial scale, and the application of such carbon to electrical purposes,
notably for lighting, electrolysis, and batteries.
In carrying this invention into practice, carbons manufactured in the ordinary
manner for electrical purposes are subjected to such a temperature as will soften,
weld, fuse or sublime the same and they are thus transformed (either completely
or in part) into graphitic carbon or graphite. I use the term graphite to indicate
that description of carbon which when treated by Berthelot's method is transformed
into graphitic oxide. I cannot state the exact temperature to which the carbon
is to be raised for the reason that it is very difficult if not impossible to measure
it in the present state of science. I will however define it in as precise a manner
as possible by stating as above mentioned that it is to be at least equal to that at
which carbon softens, welds, fuses or sublimes.
Carbons which have been submitted to this high temperature possess for
electrical purposes, special properties which differentiate them in a marked degree
from those which are manufactured by the ordinary methods heretofore in use.
With regard to arc-light carbons their conductivity is considerably increased
and their rate of consumption is diminished, and as regards carbons for use in
electrolysis or as battery carbons their conductivity is increased and they are
moreover considerably less attacked or disorganised by the action of nascent
gases,
Agglomerate carbons are at present made by taking carbon in different forms or
modifications and mixing it with a suitable agglutinant and then subjecting the
mixture to pressure suitable for moulding it or forcing it through a die.
The carbon preferably employed is lamp black or amorphous carbon and gas
retort carbon; this last is improperly called "retort graphite" and is in fact what
I term metallic carbon.

page_text: These different kinds of carbon and that resulting from the baking or carbonizing
of the agglutinant, which is generally tar, are all brought by the baking process
adopted in the ordinary manufacture of carbon heretofore in use to a state or
condition which does not go beyond that which I have herein called metallic
carbon.
To attain to the graphitic state defined by Berthelot it is necessary as herein-
before stated to raise the temperature of baking to a degree which effects the
softening, welding, fusion or sublimation of the carbon.
This temperature varies according as the operation is conducted in a total or a
partial vacuum, or under ordinary atmospheric or higher pressures, and in atmo-
spheres of gases such as carbonic oxide, nitrogen, hydrogen and sulphide of carbon;
but in all cases in order to obtain the total or partial transformation of the carbon
into graphite, it is necessary to heat it to the temperature, (variable according to
the pressure and surroundings) at which the carbon softens, welds, melts or
sublimes.
I obtain this graphitic carbon as hereinafter described. I pass the carbon to
be treated through a suitable electric furnace so that a small portion of the carbon
is first heated to incandescence between two fixed contacts which are connected
with the poles of an electric generator and then each successive portion until the
whole mass has been treated or brought to the temperature herein before mentioned.
These contacts instead of being fixed may be arranged to slide on the carbon which
remains in the same position. It will be seen that by both methods of treatment
only a small portion of the carbon is treated in a given time so that bending,
sagging or fracture is avoided, while the whole mass is exposed by the successive
treatment of its parts to the required temperature herein before set forth.
I also, according to my invention, may bring a part more or less deep of the
carbon which is to be transformed into graphite to the temperature which I
have herein above defined. In this case the transformation is only partial.
I obtain such a result by subjecting the surface of the carbon to the action of the
electric arc, by moving the arc over the whole of the surface as the operation
proceeds, or by moving the carbon, the arc remaining stationary.
I thus transform the outer layers of carbon to a greater or less depth and I
condense within the piece undergoing treatment carbon vapours in a manner more
or less complete according to the mean temperature to which the whole of the mass
is subjected. These condensed carbon vapours produce greater or less quantities
of graphite in the interior of the carbon.
Again I can either in the air or in suitable atmospheres of special gases and with
or without pressure conduct the electric arc to the surface of the piece to be
transformed by connecting one of the poles of a suitable source of electricity with
the piece to be treated and striking the arc by means of a cylinder or rod of carbon
connected to the other pole of electricity. By moving this carbon rod along the
piece to be treated or by moving the piece to be treated, the arc is brought into
contact with the whole surface of the piece and the outer layers of the piece are
transformed into graphite to a greater or less depth varying with the quickness of
movement given to the carbon rod or to the plate itself and with the intensity of
the current employed. The piece of carbon treated may form the common electrode
of two or several couples of arcs in series.
Again I can raise the surface of the piece to be treated to the suitable
temperature, without the aid of the arc, but by the heat generated on the surface
by the current itself.
For this purpose I connect one of the poles of the source of electricity to the
piece to be treated and the other pole to a piece of carbon of suitable shape. I
place this last piece in contact with the piece to be treated, and if the current has
an intensity suitable to the shape of the carbon, a temperature suitable for the
transformation will be developed at the point of contact. I cau interpose powdered
carbon between the piece to be treated and the carbon electrode, so as to increase
the resistance at the point of contact and facilitate the attainment of the required

page_text: temperature. It will be seen that by touching all the parts of the piece to be
treated under the conditions above stated the surface of the piece will be trans--
formed more or less deeply.
In fact by subjecting the surface of the piece to the temperature above defined
1 cover the same with a layer of greater or less thickness of melted or welded
carbon.
Graphitic carbon thus commercially obtained may be advantageously applied to.
electrical engineering for many uses.
I have herein before spoken of the treatment of pieces of carbon having certain
dimensions, but I may apply this treatment to granular or powdered carbon by
allowing the same to pass between two electrodes fixed at a short distance from.
each other and connected with the respective poles of an electric generator at a
rate of flow sufficient to bring the portion of powdered or granular carbon between
the electrodes to incandescence at the temperature herein before mentioned..
Successive portions of the granulated or powdered carbon are subsequently
continuously treated until the whole has been transformed into graphitic carbon.
Instead of bringing the carbon to incandescence it may be heated by the electric
arc in suitable apparatus such as is described in the Specification of Letters
Patent No. 1334093. The graphitic carbon produced may be used in the
manufacture. of carbon by agglomeration or in telephones and microphones, or in
other ways.
I have hereinbefore described the treatment of carbons which have been first.
manufactured in the ordinary manner, but it is obvious that I can treat crude
carbon of any shape or form by first taking precaution to ensure the distillation of
the volatile products contained therein.
Having now particularly described and ascertained the nature of the said inven-.
tion 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. A method of converting rods, plates or pieces of carbon into graphite by
raising the same by means of an electric current to a state of incandescence at the
temperature hereinbefore described by passing successive portions of the rods,
plates or pieces of carbon between two contacts connected with the respective poles
of an electric generator and at a short distance from each other until the rods,
plates or pieces of carbon are entirely converted.
2. A method of converting rods, plates or pieces of carbon into graphite by
raising the same to a state of incandescence at the temperature herein before described
by moving two contacts connected with the respective poles of an electric generator
over small portions of the same until the whole of the rods, plates or pieces of
carbon have been converted.
3. A method of converting rods, plates or pieces of carbon into graphite by
raising the same to the temperature herein before described obtained by one or more
electric arcs by passing successive portions of the same before or between one
or more electrodes, the carbon material itself forming the second pole of each
electrode.
4. A method of converting rods. plates or pieces of carbon into graphite by
raising the same to the temperature herein before described by causing the arc or
arcs to travel over successive portions of the same until the whole is heated, the
carbon material itself forming the second pole of each electrode.
5. The conversion of powdered or granular carbon into graphitic carbon,.
substantially as described.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant..