Improvements in Incandescent Electric Lamps.
Year: 1897

page_text: PROVISIONAL SPECIFICATION,
Improvements in Incandescent Electric Lamps.
We, FRANÇOIS GABRIEL and HENRI ANGENAULT, both of 24, Boulevard. Poisson-
niere, Paris, in the Republic of France, Engineers, do hereby declare the nature
of this invention to be as follows: -
This invention relates to an improvement in the construction of electric lamps
in which, in principle, a carbon filament placed in a bulb in which a vacuum is
created, is raised to incandescence when it is traversed by an electric current.
Hitherto incandescent electric lamps have been capable of being usefully
employed only when the voltage is fairly low and remains at a maximum of about
110 volts, which is the potential generally adopted; lamps of high voltage, of
from 200 to 300 volts for example, not being adapted for general use as their
life is very short. These lamps, in fact, are liable to the grave defect, that in
the majority of cases discharges take place between the two leading in wires to
which are fixed the two extremities of the carbon filament, and this more especially
in proximity to the soldered joints; these discharges render the lamps utterly
useless and indeed frequently cause them to burst.
Owing to this defect, lamps of high voltage have not come into general use.
Our invention permits of the construction, of lamps with which such accidents
do not occur. It consists of the introduction into a small glass tube of each of
the leading in wires to which are soldered the ends of the carbon filament;..this
tube should be of sufficient length to enclose the joint, and of a diameter large
enough for this joint and also a portion of the wire to be free.
By constructing lamps of high voltage in this manner, the discharges. previously
referred to do not take place whilst they are in use.
It will be understood that we do not confine ourselves to the construction of
lamps having a fixed voltage, and that as our method permits of manufacturing
lamps capable of running at a high voltage, such as 200 volts, we reserve the
right to apply it to lamps of any voltage, both greater than the figure here given
by way of example and to lamps of the voltage hitherto generally employed.
We do not limit ourselves to any particular dimensions for the tubes which
may be either of glass or of any vitrified substance similar to glass.
T
1007
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
COMPLETE SPECIFICATION.

page_text: of this invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:-
This invention relates to an improvement in the construction of electric lamps
in which, in principle, a carbon filament placed in a bulb in which a vacuum is
created, is raised to incandescence when it is traversed by an electric current.
In order that our invention may be readily understood, we will describe the
same with reference to the accompanying drawing, in which:
Figure 1 is a sectional view of a lamp of the ordinary type, and
Figure 2 a sectional view of a lamp according to our invention.
Hitherto incandescent electric lamps have been capable of being usefully
employed only when the voltage is fairly low and remains at a maximum of about
110 volts, which is the potential generally adopted; lamps of high voltage, of
from 200 to 300 volts for example, not being adapted for general use as their life
is very short. These lamps, in fact, are liable to the grave defect, that in the
majority of cases discharges take place between the two leading in wires A A
(Figure 1) to which are fixed at b6 the two extremities of the carbon filament B,
and this more especially in proximity to the soldered joints; these discharges
render the lamps utterly useless and indeed frequently cause them to burst.
Owing to this defect, lamps of high voltage have not come into general use.
Our invention permits of the construction of lamps with which such accidents
do not occur. It consists of the introduction into a small glass tube C Figure 2
of each of the leading in wires A' to which are soldered at 61 the ends of the carbon
filament B; this tube should be of sufficient length to enclose the joint, and of
a diameter large enough for this joint and also a portion of the wire to be free.
By constructing lamps of high voltage in this manner, the discharges previously
⚫ referred to do not take place whilst they are in use.
It will be understood that we do not confine ourselves to the construction of
lamps having a fixed voltage, and that as our method permits of manufacturing
lamps capable of running at a high voltage, such as 200 volts, we reserve the
right to apply it to lamps of any voltage, both greater than the figure here given
by way of example and to lamps of the voltage hitherto generally employed.
We do not limit ourselves to any particular dimensions for the tubes C which
may be either of glass or of any vitrified substance similar to glass.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:-
In incandescent electric lamps, the improvement which consists in surrounding
by a tube of glass or other vitrified substance each of the metallic wires to which
are soldered the extremities of the carbon filament which tube should rise above
the point where the carbon filament is soldered to the metallic wire, and the joint
as well as a portion of the wire should be free within the tube, as above described
and specified with reference to the accompanying drawing.
CIL
P
1 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.