A Method of Producing Carbon Fibres or Filaments.
Year: 1886

page_text: Date of Application, 21st Sept., 1886.
Complete Left, 18th June, 1887.
Complete Accepted, 19th July, 1887.
A Method of Producing Carbon Fibres or Filaments.
I, WILLIAM MAXWELL, of No. 34 Claybrook Road, Fulham, in the County ol
Middlesex, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to a method of producing fibres or filaments of carbon.
For this purpose, within a closed vessel which, by continuous renewal, I keep
charged with gas or vapour consisting mostly of hydrocarbon, preferably at a pressure
below that of the atmosphere, I place a refractory conductor which I heat to a high
temperature by passing through it a current of electricity. Fibres or filaments of
carbon become formed appearing attached to the conductor and standing out from it
like hairs, and these can, after cooling, be removed.
The vessel in which the process is carried on may be partly of glass, or if of opaque
material, it should be provided with talc or glass sight holes for watching the
operation.
ABEL & IMRAY,
28, Southampton Buildings, London, W.C.,
Agents for the Applicant.

page_text: I, WILLIAM MAXWELL, of No. 34 Claybrook Road, Fulham, in the County of
Middlesex, 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 :-
Fibres of carbon resembling horse hairs are sometimes produced in coke ovens, and
similar forms of carbon have been obtained in highly heated vessels and retorts
containing hydrocarbon gases or vapours but these have generally been so irregular in
form and construction that they cannot be successfully applied for such purposes as
incandescent electric lamps.
4
My invention relates to a method of producing fibres or filaments of carbon of a very
pure and regular character.
For this purpose, within a closed vessel which, by continuous renewal, I keep
charged with a gaseous fluid consisting of or containing hydrocarbon, preferably at a
pressure below that of the atmosphere, I place a refractory conductor which I heat to
a high temperature by passing through it a current of electricity. Fibres or filaments
of carbon become formed appearing attached to the conductor and standing out from it
like hairs, and these can, after cooling, be removed.
The vessel may be an iron cylinder having strong metal conductors passing through
insulated stuffing-boxes to the interior and terminating there in massive clamps which
grip and support the intermediate refractory conductor. This conductor is preferably
made as a cylindrical bar or tube of dense hard carbon with enlarged ends to ensure
good and safe electrical contact with the leading conductors. The refractory conductor
may be enclosed within a tube insulated from it, and heated by radiation from it. The
vessel has at its bottom and top pipes for the admission and emission of the gas and
means for regulating the pressure and rate of flow and it should be furnished with
sight holes for observing the interior. It is sometimes advantageous to place a screen
of iron or other suitable refractory material around the conductor but at some distance
from it in order to equalise the temperature in the space enclosed by it.
The gas employed should be free from moisture, it may be coal gas carefully prepared
from bitumenous coal or other gas containing suitable hydrocarbons.
The temperature of the refractory conductor depends more or less upon its size and
the quality and density of the gas operated upon, usually a white heat is necessary
for the formation of fibres the length of which seems to depend chiefly upon the
thickness of the conductor.
The pressure of the gas may vary within comparatively wide limits and can best
be determined experimentally in each case. It should seldom exceed that of the
atmosphere, generally it should be considerably lower.

page_text: In carrying out the process I connect the entrance pipe of the vessel to a supply of
the gas and the exit pipe to an air pump or other means of continuous exhaust, and
having displaced the air I cause the gas to circulate through the vessel at regulated
pressure and rate of flow I then close the circuit for the leading conductors, and then
the refractory conductor having attained the necessary temperature, fibres of carbon
form liko fine hairs projecting from it.
As the fibres are only formed under physical conditions of a very critical character
great care has to be taken in producing the temperature required and maintaining it
without variation or interruption while the apparatus is kept quite still and the gas is
caused to circulate slowly through it at a uniform speed and pressure.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I declaro that what I claim is :-
The herein described inethod of producing fibres or filaments of carbon from gas
containing hydrocarbon caused to circulate through a vessel containing a refractory
conductor heated by an electrical current.
ABEL & IMRAY,
Agents for the Applicant.