IMPROVEMENTS IN THE MANUFACTURE OF ELECTRIC INCANDESCENT LIGHTS IN THE VACUUM
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Auguste Lèon Jousselin at the Office
of the Commissioners of Patents on the 29th April 1882.
AUGUSTE LEON JOUSSELIN, of Paris, Republic of France
IMPROVEMENTS IN
THE MANUFACTURE OF ELECTRIC INCANDESCENT LIGHTS IN THE VACUUM
My invention relates to the manufacture of incandescent lamps and may be
divided into four parts; namely, first the means of constructing the transparent
shell and insulating the conductors, second, the treatment of the materials from
which the incandescing carbons are made, third, the manufacture of the incandescing
carbons, and fourth, the attachment of the carbons to the conductors. The trans-
parent shell consists of a glass globe closed by a metallic fitting. The opening of
the globe is surrounded by a metallic ring sealed to the latter by a fusible sulphide
or an enamel composed of 100 parts of sand, 250 parts of minium, and 150 parts
of protoxide of copper. The opening left by the ring is closed by a metallic plate
made hermetic by casting into the joint a fusible solder or tin. To the closing
plate are cast or soldered two tubes of about 30 to 40 millimeters length through
which pass the copper conductors, a hermetic joint being formed by the above-
described composition. Another method of effecting the required insulation
consists in taking a tube of glass, porcelain or earthenware, having a metallic
surface and annealing it by red heat. Into this tube the conductor is soldered as
above and the whole tube soldered or cemented into the metallic tube which forms
part of the closing plate. As solder or cement a copper alloy may be used which
becomes soft at a temperature of 120 degrees Centigrade, or a mixture of about
80 parts of litharge with about 20 parts of glycerine, and the surface of the glass
which comes in contact with the cement may be roughened by a concentrated
alkali. As raw material for the carbon filaments I use strips of woven fabrics,
round or flat wicks and other textile fabrics consisting chiefly of cellulose. This
material is impregnated with cellulose by macerating it in a solution of plastic
cellulose hereinafter described, washing with water and ammonia, drying and
steeping it in a solution of sugar, coating it with pure graphite and drying gently.
The product is then made up into the required shape, further dried at a temperature
of 150° Cent, and carbonized. The plastic cellulose is made as follows:-Paper,
carded cotton, ramie fibre, or purified and bleached linen is washed in hydrochloric

page_text: acid diluted with two thirds of water, neutralized by ammonia and almost
completely dried. It is then introduced in small quantities into a mixture of
sulphuric acid, hydrochloric acid and water. When the material is nearly dissolved,
the acid is rapidly filtered through a platinum sieve No. 80, and water added, the
whole being then put on a filtering cloth, washed with distilled water, the material
left to dry a little and the washing continued with ammonia water until completo
neutralization is effected. The material is then rinsed with water, and water
pressed out until the required density is obtained, after which the product is
placed in vessels and the latter closed. The plastic cellulose thus prepared may be
rolled out, cast, or drawn and cut into cylindrical or otherwise shaped pieces, with
or without the addition of magnesia, aluminium, or graphite, after which it is
dried. It may also be mixed with "hydro-cellulose," if it is formed into large
pieces. The carbon filaments may be made from celluloid, moulded hot in a press
and treated with any reducing substance, such as an alcoholic or methylic solution
of sulpho-hydrate of ammonia. When the reduction is finished the sulphur is
removed by a mixture of alcohol and carbo-sulphide, after which the product is
washed, dried and carbonized. Hydro-cellulose may be employed for making
carbon, by agglomerating it with plastic cellulose above described, which serves as
a binding substance, with or without the addition of graphite, aluminium or
magnesium. The carbonization of the incandescing conductors according to my
invention is not effected simply by the influence of heat on hydrocarbon, but by
the reaction or double decomposition between a carbon compound and a body
capable of supplying a volatile compound which attracts hydrogen, by which
method I obtain a very abundant precipitate of carbon at a high temperature, the
physical condition of which depends on the temperature at which it has been
formed. This carbon impregnates completely the incandescing conductor formed
in this atmosphere, which may be a mixture of light hydro-carbon vapours with
sulphide of carbon or chlorine. The carbon filaments are mounted in a substance
consisting of an agglomerate of pure graphite with pure sugar. The carbons are
sealed to this mass by means of a cement composed of the same paste, but more
diluted and applied with a brush, the whole being annealed to red heat in carbon
powder. The metallic conductors are introduced into holes prepared in advance
and a perfect contact obtained by means of cement filled between the conductor
and the graphite; or a galvanic deposition of copper or nickel may be produced in
the joint of the two parts.