Improvements in the Manufacture of Filaments f Electric Lamps.
Year: 1898

page_text: Date of Application, 29th Jan., 1898
Complete Specification Left, 28th Oct., 1898-Accepted, 14th Jan., 1899
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Filaments f
Electric Lamps.
Incandescent
I, ROBERT MULLARD, of 175, Grange Road, Bermondsey, in the County of London,
Chemist, do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in the manufacture of filaments for
incandescent electric lamps.
According to my invention 1 employ a substance or substances of the kind here-
inafter referred to, some of which may be used alone while others are preferably
mixed with carbon or carbonaceous material, whereby I am able to make the filament
shorter and thicker than heretofore and at the same time render its electrical
resistance extremely high. The substances in question are what are known as
carbides and I may employ for the purpose of my invention carbide of calcium, of
barium, of strontium, of iron, of zinc, of copper, of aluminium, of magnesium, of
inanganese, of boron, or of silicon, either separately or two or more of them in com-
bination or admixture with each other.
The desired carbide or carbides are reduced to an impalpable powder and when
desired are intimately mixed with the carbonaceous material such as coke, graphite,
or retort carbon, also reduced to an impalpable powder. The proportions in which
the materials are used depend upon the degree of electrical resistance that the fila-
ments are desired to have, and will vary accordingly.
The aforesaid impalpable powders are intimately mixed and formed into a plastic
mass of about the consistency of dough by the aid of tar or other suitable binding
material. The said mass while in its plastic condition is then pressed through a die
to form it into a thread or filament of the required diameter. Or the aforesaid
powders may be intimately mixed together with a solution of cellulose in chloride of
zinc and the solution thus obtained may be squirted through a nozzle of the required
size for forming the filaments.
The filaments thus prepared are carbonized, flashed, mounted in globes, and other-
wise treated in the manner usual in the manufacture of incandescent electric lamps.
Dated this 29th day of January 1898.
HASELTINE, LAKE & Co.,
45, Southampton Bundings, London, W.C., Agents for the Applicant.
45, Southampton Bundings, London, 10. ngomes 10E
COMPLETE SPECIFICATION.
CATC PP
Improvements in the Manufacture of Filaments for Incandescent
Electric Lamps,
I, ROBERT MULLARD, of 175, Grange Road, Bermondsey, in the County of London,
Chemist, 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 :-
This invention relates to improvements in the manufacture of filaments for incan-
descent electric lamps.

page_text: According to my invention I employ a substance, or substances of the kind herein-
after referred to, some of which may be used alone while others are preferably mixed
with carbon or carbonaceous material, whereby I am able to make the filament shorter
and thicker than heretofore and at the same time render its electrical resistance
extremely high. The substances in question are what are known as carbides and I
may employ for the purpose of my invention carbide of calcium, of barium, of
strontium, of iron, of zinc, of copper, of aluminium, of magnesium, of manganese, of
boron, or of silicon, either separately or two or more of them in combination or
admixture with each other.
The desired carbide or carbides are reduced to an impalpable powder and
when desired are intimately mixed with the carbonaceous material such as coke,
graphite, or retort carbon, also reduced to an impalpable powder. The proportions
in which the materials are used depend upon the degree of electrical resistance that
the filaments are desired to have, and will vary accordingly.
For instance I may use from 20 to 50 per cent. of carbide of silicon with
from 80 to 50 per cent. of carbon; or 90 per cent. of carbide of calcium with
10 per cent. of carbon; or 60 per cent. of carbide of magnesium with 40 per
cent. of carbon. The form of carbon used in the above cases being furnace
coke.
The aforesaid impalpable powders are intimately mixed and formed into a plastic
mass of about the consistency of dough by the aid of tar or other suitable binding
material. The said mass while in its plastic condition is then pressed through a die
to form it into a thread or filament of the required diameter. Or the carbides of
silicon, boron and manganese either separately or two or more of them in combination
or admixture with each other may be intimately mixed with a solution of cellulose in
chloride of zinc and the mixture thus obtained may be squirted through a nozzle of
the required size for forming the filaments.
The filaments thus prepared are carbonized, flashed, mounted in globes and
otherwise treated in the manner usual in the manufacture of incandescent electric
lamps.
my
said
1. Having now particularly described and ascertained the nature of
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1. In the production of filaments for incandescent electric lamps, the use of the
hereinbefore mentioned carbides either separately or two or more of them in com-
bination or admixture with each other, and with or without an admixture of
carbonaceous material such as coke, graphite or retort carbon, substantially as described
and for the purpose specified.
2. In the production of filaments for incandescent electric lamps, the use of the
hereinbefore mentioned carbides either separately or two or more of them in com-
bination or admixture with each other, and a solution of cellulose, substantially as
described and for the purpose specified.
3. Filaments for incandescent electric lamps composed of one or more of the
hereinbefore mentioned carbides, either with or without an admixture of carbon,
substantially as described..
.
01 October 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.