An Improved Method of Renewing the Carbon Filaments of Incandescence Electric Lamps.
Year: 1890

page_text: Date of Application, 29th Apr., 1890-Accepted, 14th June, 1890
COMPLETE SPECIFICATION.
[Communicated from abroad by LA SOCIÉTÉ "L'INCANDESCENCE ELECTRIQUE,"
of 4, Rue Bréguet, Paris, in the Republic of France.]
An Improved Method of Renewing the Carbon Filaments of
Incandescence Electric Lamps.
I, HENRY HARRIS LAKE of the firm of Haseltine Lake & Co. Patent Agents
Southampton Buildings in the County of Middlesex 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 a method of repairing the carbon filaments of incan-
descence electric lamps, which will hereinafter be described with reference to the
accompanying drawing.
In this drawing, Figure 1 shows a lamp wherein the carbon filament is broken and
which is therefore not in use. In this instance the whole mounting is lost, because
the said filament not being entire the lamp cannot operate.
Figure 2 shows this lamp open at the top of the bulb at A. The filament which
was broken has been entirely removed, lengths of only about two millimetres of the
old carbon having been left upon the electrodes of platina to serve as joining pieces
for establishing the connections at B and at C. In this Figure is also shown the level
of the hydrocarburet which can be varied but must be such that the electrodes shall
be entirely covered.
Figure 3 shews a fresh carbon filament introduced into the bulb through the
opening A the extremities B and C¹ being presented to the joining pieces B and C.
This carbon filament is held in its position by a copper wire attached to a stand
whose arm can be raised or lowered according to exigencies. The aforesaid
extremities B and C are brought near to the joining pieces B and C by means of
small pincers the upper part of which is connected through a flexible wire with one
of the poles of any source of electricity, such as a dynamo, a primary or a secondary
battery.
The connection is effected at B and B by first placing the filament in a line and in
contact with the joining piece and sending the electric current through the same.
Under the action of the current the hydrocarburet is partially decomposed and
at B and B is formed a deposit of solid carbon which secures the extremity of the
fresh carbon filament upon the short joining piece of the old carbon. Then the
current is reversed by means of a reverser included in the circuit of the lamp and
the same operation is carried out at C and by means of the said pincers. The
carbon is then secured by its two extremities in the place of the old one.
It will be understood that if the carbon filament has been measured before its
introduction and connection, and if its resistance is the same as that of the filament
whose place it must occupy, the lamp will possess the same electromotive power and
intensity which it had during its first period of lighting. Accordingly the improved
method enables the utilization of all the bulbs of the lamps the filament of which
has been broken a first time, and which have heretofore become valueless in con-
sequence of the breakage of their filament. The lamps repaired according to the
said method will have the same value as before because the broken filament has been
replaced by a new one.
In this manner lamps of any electromotive power can be obtained, for the con-
nection of a carbon of any resistance within the limits of those of the lamps in use
can be effected in a bulb.
The lamp is mounted upon a support, and included in a shunt circuit in connection
and a current reverser is included in the circuit of the lamp.
Figure 4 shows the lamp when the carburet is removed, and when the connection
D...

page_text: has been effected. The bulb is provided with a glass tube having a contracted part
or neck at the point A. This tube is connected with the pump whereby the air is
exhausted from the lamp. When the vacuum has been produced the bulb is sealed
and the tube removed by means of the blow pipe. The lamp is thus completely
constituted again without any change in its form and without dismounting its parts,
the work of repairing being entirely executed through the opening A.
It may be observed that the above-described operations can be carried out several
times, in fact they can be repeated whenever the filament breaks, which will never
take place at the connecting points. These different operations are less expensive
than those which are required in the manufacture, excepting production of the vacuum
which is the same in both instances.
By this improved method the cost of the raw material, excepting the carbon and
also that of a great part of the hand labour including the entire expense of giving
the lamp its form is obviated and nearly all the waste products of the manufacture
are saved.
Figure 5 shows a lamp which is ready to be used in the place which it previously
occupied, that is to say adapted to be included in the same circuit as before because
the carbon filament which has replaced the filament previously employed and
does not differ from the latter, consequently the constants are the same in both cases.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me by my
foreign correspondents I declare that what I claim is :-
The method of repairing or replacing the carbon filaments of incandescence electric
lamps, which consists in introducing into the bulb of the lamp a new filament, a
liquid hydrocarburet for connecting the extremities of the aforesaid filament with
the joining pieces formed by the ends of the broken filament which are adapted to
receive the same substantially as and for the purpose herein before described.
Dated the 20th day of Annil 1800
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.