IMPROVEMENTS IN MANUFACTURE OF CARBONS FOR INCANDESCENT ELECTRIC LAMPS
Year: 1884

page_text: We MORTIMER EVANS and FRANK WYNNE both of 112 Belvedere Road,
Lambeth, London, Civil Engineers, do hereby declare the nature of said invention
for IMPROVEMENTS IN MANUFACTURE OF CARBONS FOR INCANDESCENT ELECTRIC
LAMPS, to be as follows:-
Our invention relates principally to that kind of lighting apparatus in which a
filament of carbon is maintained in a state of incandescence by the passage of an
electric current.
Our invention relates to material from which carbon filaments may be produced
and in treating this and consists in first obtaining a substance of a homogeneous
nature composed of a carbonizable substance and treating it in such a way as to
form filaments or threads of uniform sectional area and quality.
For the material of the carbon filament, we take a solution of cellulose, and
this in plastic or semi-liquid or liquid state we project or we allow to flow and
regulate its flow through an orifice or die of any suitable shape so as to form, when
suitably treated, strings or bands or tubes, (which we prefer hereinafter to refer to
as filaments) of uniform section and of any required length. On issuing from the
orifice we project the stream of cellulose solution into a liquid or mixture of liquids
or a solution or a gas such as has the property of fixing setting or coagulating the
issuing stream, thereby enabling it to retain the form given to it, such liquid or gas
I prefer hereinafter to refer to as the "fixing fluid." One material which we
find it convenient to employ for production of the cellulose solution is obtained by
treating cotton or other suitable vegetable fibre, thread, or fabric, with a solution
of zinc chloride and this solution I fill into a vessel from which after treatment in
vacuo we afterwards express it through the desired orifice into the fixing fluid by
means of a mercury pressure from below, but we do not limit ourselves to the
above method of passing the solution through the desired orifice as we sometimes
allow it to flow through by its own weight or suck it through.
This fixing fluid we may form of sulphuric ether or other suitable liquid, or gas
and we may add to it hydrochloric acid or any other suitable liquid for the purpose
of purifying the fixed or coagulated thread. We sometimes mix a cellulose solution
with albumen or other convenient coagulating body and a stream of this on issuing
from the orifice we can conveniently coagulate by means of heat applied through
the fixing fluid.

page_text: We do not limit ourselves to the above particular solution of cellulose or to one
so obtained and we sometimes use solution of dextrine or glucose for the purpose;
and we do not limit ourselves to the herein before described method of expressing
the cellulose through the orifice the filament when obtained is then treated by any
well known processes and carbonized in any suitable manner, or it may be treated
as follows:
Our invention further relates to treatment of filaments for subsequent carbonizing
for use in electric lamps and which have been obtained either as herein before
described or by treatment of vegetable fibre with chloride of zino solution, or
sulphuric acid, and which has thereby been parchmentised, acquired in irregular
form and is in a moist and pasty state-with little relative cohesion-and which we
desire to dry and at the same time to reduce to a uniform circular cross section.
This we effect by rolling the filaments between smooth plates, preferably of polished
metal one or both of which may be heated. We find it convenient for this
purpose to have our thread in the moist parchmentised condition on a drum, and
pass it over a metal box (say of copper) the upper surface of which is polished and
through the inside of which we pass steam or heated air or water. The thread as
it passes along the top of this box passes successively under several plates of
polished metal which are given a motion, transverse to the thread the first rolling
the thread with comparatively light pressure, the succeeding ones with a successively
increasing pressure, so that ultimately the parchmentised thread passing over the
box or succession of boxes under rollers issues in a more or less perfectly cylindrical
form and in a completely hard and dried condition. The filament is then further
treated by any well known process and carbonized in a suitable manner.

page_text: Improvements in Manufacture of Carbons for Incandescent
Electric Lamps.
We, MORTIMER EVANS and FRANK WYNNE, both of 112 Belvedere Road,
Lambeth, London, Civil Engineers, do hereby declare the nature of our invention
for IMPROVEMENTS IN MANUFACTURE OF CARBONS FOR INCANDESCENT ELECTRIO
LAMPS, and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
Our invention relates principally to that kind of lighting apparatus in which a
filament of carbon is maintained in a state of incandescence by the passage of an
electric current.
Our invention relates to material from which carbon filaments may be produced
and in treating this and consists in first obtaining a substance of a homogeneous
nature composed of a carbonizable substance and treating it in such a way as to
form filaments or threads of uniform sectional area and quality.
For the material of the carbon filament we take a solution of cellulose in chloride
of zinc and this in plastic or semi-liquid or liquid state we project or we allow to
flow and regulate its flow through an orifice or die of any suitable shape so as to
form, when suitably treated, strings or bands or tubes, (which we prefer herein-
after to refer to as filaments) of uniform section and of any required length.
On issuing from the orifice we project the stream of cellulose solution into a
liquid such as sulphuric ether or mixture of liquids or a solution or a gas such
as the vapour of sulphuric ether, which has the property of fixing setting or
coagulating the issuing stream, thereby enabling it to retain the form given to it,
such liquid or gas we prefer hereinafter to refer to as the " fixing fluid" the
material which we find most convenient to employ for production of the cellulose
solution is obtained by treating cotton or other suitable vegetable fibre, thread
or fabric with a solution of zinc chloride of about specific gravity of 1.8 at a
temperature of about 80 to 100 degrees Centigrade which completely effects its
solution and yields a translucent liquid somewhat of the consistency of honey and
this solution we fill into a vessel filtering it when necessary and from which vessel
after treatment in vacuo we afterwards express it through the desired orifice into
the fixing fluid by means of a mercury pressure from below, but we do not limit
ourselves to the above method of passing the solution through the desired orifice
as we sometimes allow it to flow through by its own weight or suck it through.
This fixing fluid we may form of suphuric ether or other suitable liquid or gas
and we may add to it hydrochloric acid or any other suitable liquid for the purpose
of purifying the fixed or coagulated thread from the zinc salt. We sometimes mix
a cellulose solution with albumen or other convenient coagulating body and a
stream of this on issuing from the orifice we can conveniently coagulate by means
of heat applied through the fixing fluid.
We do not limit ourselves to the above particular solution of cellulose or to one
so obtained and we sometimes use solution of dextrine or glucose for the purpose;
and we do not limit ourselves to the hereinbefore described method of expressing

page_text: the cellulose through the orifice the filament when obtained is then treated by
any well known processes and carbonized in any suitable manner, or it may be
treated as follows:
Our invention further relates to treatment of filaments for subsequent carbonizing
for use in electric lamps and which have been obtained either as hereinbefore
described or by treatment of vegetable fibre with chloride of zinc solution, or
sulphuric acid, and which has thereby been parchmentized, and is in a moist and
pasty state and which we desire to dry and compress and at the same time to
reduce to a circular cross section. This we effect by rolling the filaments between
smooth plates preferably of polished metal or glass one or both of which may
be heated.
•
We find it convenient for this purpose to have our thread in the moist parch-
mentised condition on a drum, and pass it over a metal box (say of copper) the
upper surface of which is polished and through the inside of which we pass steam
or heated air or water. The thread as it passes along the top of this box passes
successively under several plates of polished metal which are given a motion,
transverse to the thread, the first rolling the thread with comparatively light
pressure, the succeeding ones with a successively increasing pressure, so that
ultimately the parchmentised thread passing over the box or succession of boxes
under rollers issues in a more or less perfectly cylindrical form and in a completely
hard and dried condition. The filament is then further treated by any well known
process and carbonised in a suitable manner.
Having now particularly described and ascertained the nature of our said,
invention and in what manner the same. is to be performed, we declare that what
we claim is
.
1. The manufacture of filaments from a homogeneous carbonizable solution of
cellulose in a solution of chloride of Zinc.
2. The coagulation of filaments of a carbonizable solution of cellulose in solution
of Chloride of Zinc by liquid sulphuric ether or other suitable coagulating liquid
medium with the admixture of hydrochloric acid or other suitable solvent. of
chloride of Zinc.
3. The coagulation of filaments of a carbonizable solution of cellulose in solution:
of chloride of Zinc by gaseous sulphuric.ether or other suitable coagulating gaseous
medium and subsequent washing in suitable liquid such as alcohol or water in
admixture with some hydrochloric acid or other suitable solvent of the chloride
of Zinc.
4. The coagulation of filaments of carbonizable. solution of cellulose in admixture.
with albumen. or other suitable body capable of coagulation by the application
of heat.
5. The "forming" of filaments prior to their carbonization between plates of
heated metal or glass.
All substantially as herein described and for the purposes set forth.