IMPROVEMENTS IN THE MANUFACTURE OF CARBON AND GRAPHITE, WHICH INVENTION ALSO COMPRISES THE FORMATION OF THESE MATERIALS INTO RODS, BARS, PROVISIONAL SPECIFICATION
Year: 1881

page_text: LETTERS PATENT to Richard Werdermann, of Princes Street, in the County
of Surrey, Civil Engineer, for an Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF CARBON AND GRAPHITE, WHICH INVENTION ALSO
COMPRISES THE FORMATION OF THESE MATERIALS INTO RODS, BARS,
PROVISIONAL SPECIFICATION left by the said Richard Werdermann at the
Office of the Commissioners of Patents on the 22nd January 1881.
RICHARD WERDERMANN, of Princes Street, in the County of Surrey, Civil
Engineer. "IMPROVEMENTS IN THE MANUFACTURE OF CARBON AND GRAPHITE,
WHICH INVENTION ALSO COMPRISES THE FORMATION OF THESE MATERIALS INTO
RODS, BARS, PENCILS, AND OTHER ARTICLES AND APPARATUS THEREFOR.”
My said Invention relates to the manufacture of carbon, and to the conversion
of carbon into graphite. Carbon and natural or artificial graphite are seldom
found in a pure condition; they usually contain iron, silica, and other impurities
which render them unfit for the purposes for which they are required. Among the
most important of these purposes is the manufacture of writing pencils and of
electrodes or "candles" for electric lamps, and it is most desirable that the carbon
or graphite used in these manufactures shall be free from all impurities.
In order to obtain such carbon or graphite I carbonize sugar, either by heat or
by the action of sulphuric acid or hydrochloric acid, or I make a mixture of sugar
with essences, oils, resin, tar, or other substances, which when decomposed by
heat leave a residuum of pure or nearly pure carbon, and I carbonize this
mixture.
The carbon thus or otherwise obtained is then mixed with a solution of pure
sugar, or with pure tar or oil, in such a manner that a homogeneous paste is
obtained, the consistency of which must be regulated according to the form of the
mould or to the length of the draw hole, hereinafter described, through which the
paste is to be pressed.
In the manufacture of carbon pencils I use a moulding press constructed with a
cylinder, in one end of which is inserted a block of metal or other suitable material.

page_text: This block is either made of one piece or of several pieces, and is provided with
draw holes, that is to say, holes through or into which this paste is to be forced to
give it the required form; the length of the said block will vary, according to the
desired hardness of the carbon pencils, as the friction of the paste in the draw
hole retards the advance of the same, and necessitates a proportionate increase of
pressure of the piston. When the pencils are to be of very great length the
moulding block is made of the same length, and constructed to be divided into
two or more parts, the line of division intersecting the hole, so that after moulding
the parts are separated, and thereby the taking of the pencils out of the mould is
facilitated. When dry the pencils are placed in a vessel containing a solution of
sugar, tar, oil, or other suitable carbonaceous liquid. The said vessel has an air
tight cover provided with a cock, and a pipe connected with a vacuum pump.
When a vacuum is produced in the said vessel the liquid fills up all the pores in
the articles or pieces of carbon, which are now dried again, and when dry are
placed into a mould of porcelain, fire clay, magnesia, or other suitable material, the
two ends of the said articles or pieces being placed on metal bearings, or being
otherwise connected with two conductors leading to the terminals of a generator
of electricity, and the carbon is heated by the passage of the electric current to a
white heat, whereby it is converted into graphite. Instead of enclosing the carbon
in a porcelain mould or pipe it may be enclosed in a platinum pipe heated to a
white heat by the passage of the electric currents: According to my Invention
not only moulded objects or articles, but also carbon powder, may be converted
into graphite by the above described processes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Richard Werdermann in the Great Seal Patent Office on the
22nd July 1881.
RICHARD WERDERMANN, of Princes Street, in the County of Surrey, Civil
Engineer. "IMPROVEMENTS IN THE MANUFACTURE OF CARBON AND GRAPHITE,
WHICH INVENTION ALSO COMPRISES THE FORMATION OF THESE MATERIALS INTO
RODS, BARS, PENCILS, AND OTHER ARTICLE AND APPARATUS THEREFOR."
My said Invention relates to the manufacture of carbon, and to the conversion
of carbon into graphite. Carbon and natural or artificial graphite seldom exist
in a pure condition; they usually contain iron, silica, and other impurities, that
render them more or less unfit for the purposes for which they are required.
Among the most important of these purposes is the manufacture of writing pencils
and of electrodes or "candles" for electric lamps, and it is most desirable that the
carbon or graphite used in these manufactures shall be free from all impurities.
In order to obtain such pure carbon or graphite I carbonize sugar, either by heat
or by the action of sulphuric acid or hydrochloric acid, or I carbonize in any
suitable manner raw cotton, wood-pulp, flax, hemp, or similar material, or I make
a mixture of sugar or of any one or more of the above named substances, with
essences, oils, resin, tar, or other substances, which, when decomposed by heat,
leave a residuum of pure or nearly pure carbon, and I carbonize this mixture.
The carbon thus or otherwise obtained is then mixed with a solution of pure sugar
or with
pure tar or oil in such a manner that a homogeneous paste is obtained,
the consistency of which must be regulated according to the form of the mould or
to the length of the draw-hole, hereinafter described, through which the paste is to
be pressed.
In the manufacture of carbon pencils I use a moulding press constructed with a
cylinder, in one end of which is inserted a block of metal or other suitable material.
This block is made either of one piece or of several pieces, and is provided with
draw holes, that is to say, holes through or into which the paste is to be forced to
give it the required form. The length of the said block will vary according to
the desired hardness of the carbon pencils, as the friction of the paste in the draw
hole retards the advance of the same and necessitates a proportionate increase of
pressure of the piston. When the pencils are to be of very great length the
moulding block is made of the same length, and is preferably constructed as shewn
in perspective in the accompanying Drawing, that is to say, the said block is
divided into two or more parts a, the line of division intersecting the hole or
holes b, into which the paste is forced, so that after moulding the parts a may be
separated, and thereby the taking of the pencils out of the mould is facilitated.
When dry the pencils are placed in a vessel containing a solution of sugar, tar, oil,
or other suitable carbonaceous liquid. The said vessel has an air-tight cover
provided with a cock, and a pipe connected with a vacuum pump. While atmos-
pheric pressure exists in the said vessel the air prevents the free entrance of the
liquid into the pores of the said articles or pieces of carbon, but when a vacuum is
produced in the said vessel, the liquid fills up these pores, the articles or pieces of
carbon, which are now dried, are placed in a mould of porcelain, fire clay, magnesia,
or other suitable material, or covered with magnesia or other suitable incombustible
material in such a manner that the carbon is protected against oxidation. The two
ends of the said articles or pieces of carbon are placed on metal bearings or are
otherwise connected with two conductors leading to the terminals of a generator of
electricity, and the carbon is heated to incandescence by the passage of the electric
current, whereby it is converted into graphite. Instead of enclosing the carbon in

page_text: a porcelain mould or pipe, and sending the current through the carbon, it may be
subjected to the radiating heat of a platinum pipe heated to incandescence by the
passage of the electric current. After cooling if the conversion of the carbon into
graphite is found not to be satisfactorily effected the carbon pencil or other article
is again subjected to the electric current. According to my Invention not only
moulded objects or articles but also carbon powder may be converted into graphite
by passing through it a powerful electric current.
Having thus fully described my said Invention, and the manner of performing
the same, I wish it understood that I do not claim the production of graphite from
carbon by means of the voltaic arc, as it is well known that this result is a natural
consequence where carbons are used as rheophores, but I claim,―
First. The manufacture of carbon by carbonizing a mixture of sugar, wood pulp,
cotton, hemp, flax, or the like, with oil, resin, tar, or other hydro-carbon.
Second. The conversion of the carbon into graphite by means of an electric
current in the manner above specified.
Third. The treatment of the carbon pencils or other articles by carbonaceous
liquid in a vacuum as and for the purpose specified.
Fourth. For the manufacture of carbon pencils the moulding block formed in
two or more parts constructed and fitted together as and for the purpose
specified.
In witness whereof, I, the said Richard Werdermann, have hereunto set my
hand and seal, this Twenty second day of July, in the year of our Lord
One thousand eight hundred and eighty one.
R. WERDERMANN. (L.S.)