IMPROVEMENTS IN THE MANU- FACTURE OF INCANDESCENT ELECTRIC LAMPS
Year: 1882

page_text: LETTERS PATENT to Frederic Des Voeux, of Imperial Chambers, Derby, in
the County of Derby, for an invention of "IMPROVEMENTS IN THE MANU-
FACTURE OF INCANDESCENT ELECTRIC LAMPS." A communication from abroad
by Alex Bernstein, of Boston, County of Suffolk, State of Massachusetts,
United States of America.
PROVISIONAL SPECIFICATION left by the said Frederic Des Voeux at the
Office of the Commissioners of Patents on the 2nd June 1882.
MANUFACTURE OF INCANDESCENT ELECTRIC LAMPS
"
FREDERIC DES VOEUX, of Imperial Chambers, Derby, in the County of Derby,
"IMPROVEMENTS IN THE
(A communication from abroad by Alex Bernstein, of Boston, County of Suffolk,
State of Massachusets, United States of America.)
The main objection to the electric vacuum lamps in which a carbon filament is
employed as the light-giving agent has been the want of permanency and
reliability, as the delicate filament was too easily destroyed by exterior or interior
influences, so that no absolute reliance could be placed on this class of electric
lainps.
The object of the present invention is to produce an electric lamp which has the
advantage of increased durability and illuminating power, owing to the fact that
substances are employed which are capable of resisting the action of strong
currents, so as to impart a high degree of efficacy and permanency to the lamp.
The invention consists of an electric lamp, the light-giving part of which is
made of any substance having the property of phosphorescence, and which is either
entirely or partly covered with a deposit or film of carbon.
1
The bulb or globe which encloses the light-giving part of the improved electric
lamp has a stopper or closing part which is sealed into the neck of the bulb. The
bulb is evacuated in the usual manner through a central tube or channel of the
stopper. The platinum conducting wires are sealed into an annular collar of
the stopper, which collar is arranged at some distance below the upper end of the
central upward-extended portion of the stopper, so as to be little, if at all affected
31

page_text: by the heat emitted from the light-giving part. The conducting wires may also
be sealed to the uppermost end of the central portion of the stopper if it be desired
to increase the stability of the former.
The wires are then spread apart so as to clamp the light-giving part by means
of enlarged ends. The light-giving part is made of oval, cylindrical, spherical,
oblong, or any other shape, and composed of any substance having the property of
phosphorescence, such as calcined egg or oyster shells, chalk, lime, fluor-spar, the
compounds of strontium, magnesium, calcium &c. This light-giving part is partly
or entirely covered with a film of carbon which is deposited thereon by chemical
or mechanical means, said film serving to conduct the current from one wire to the
other while the substratum of phosphorescent material serves as a support or
carrier for the film of carbon and prevents the destruction of the same.
substratum or carrier has the properties of non-fusibility and non-conductivity and
is heated up by the intense heat of the current, so as to form a luminous body, the
light of which does not appear when entirely covered with carbon, while it is
clearly discernible at that part which is not covered with carbon.
The
The large surface of the incandescent film of carbon furnishes a large light-giving
surface, and consequently lamps of greater candle-power than can be furnished by
lamps with carbon filaments.
If the light-giving part be only partly covered with carbon, as in the case of
suspended lamps, the covered portion will emit an intense light, while the
remaining portion will emit a much softer light, which is due to the heating up of
this part by the carbon-covered portion. If the lamp be used as a wall lamp, the
front half of the light-giving part is covered with carbon, so as to emit a strong
light in front and a comparatively weak light at the rear.
If a light of less power is required, the carrier may be covered with a film of
spiral shape.
The essential advantages of a lamp of this construction are its freedom or
comparative freedom from accidental destruction, its greater economy both as to
construction and as to light-giving power, and the higher illuminating power
which is capable of being obtained by reason of the increased light emitting
surface.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Frederic Des Voeux in the Great Seal Patent Office on the
18th October 1882.
وو
FREDERIC DES VEUX, of Imperial Chambers, Derby, in the County of Derby,
"IMPROVEMENTS IN THE MANUFACTURE OF INCANDESCENT ELECTRIC LAMPS-
(A communication from abroad by Alex Bernstein, of Boston, County of Suffolk,
State of Massachusets, United States of America).
The main objection to the electric vacuum lamps in which a carbon filament
is employed as the light-giving agent has been the want of permanency and
reliability, as the delicate filament was too easily destroyed by exterior or interior
influences, so that absolute reliance could hardly be placed on this class of electric
lamps.
The object of the present invention is to produce an electric lamp which has the
advantage of increased durability and illuminating power, owing to the fact that
substances are employed which are capable of resisting the action of strong
currents, so as to impart a high degree of efficacy and permanency to the lamp.
The invention consists of an electric lamp, the light-giving part of which is
made of any substance having the property of phosphorescence and which is either
entirely or partly covered with a deposit or filin of carbon..
In the accompanying Drawings Fig. 1. represents a vertical central section of an
electric lamp constructed according to my invention. Fig. 2. is a horizontal
section of the same on line x x of Fig. 1, and Figs. 3 and 4 are details of the same.
Similar letters of reference indicate corresponding parts.
Referring to the Drawings A represents the bulb or globe which encloses the light-
giving part of my improved electric lamp, and B the stopper or closing part which is
sealed into the neck of the bulb. The bulb is exhausted in the usual manner through
a central tube or channel a of the stopper B. The platinum conducting-wires CC
are sealed into an annular collar 6 of the stopper, which collar is arranged at some
distance below the upper end of the central upward-extended portion of the stopper,
so as to be little, if at all, affected by the heat emitted from the light-giving part.
The conducting wires C C may also be sealed to the uppermost end of the central
portion of the stopper if it be desired to increase the stability of the former. The
wires are then spread apart so as to clamp the light-giving part D by means of
enlarged ends C¹. The light-giving part D is made of oval, cylindrical, spherical,
oblong or any other shape and composed of any substance having the property of
phosphorescence, such as calcined egg or oyster shells, chalk, lime, fluor-spar, the
compounds of strontium, magnesium, calcium &c. This light-giving part D is
partly or entirely covered with a film of carbon, which is deposited thereon by
chemical or mechanical means, said film serving to conduct the current from one
wire to the other while the substratum of phosphorescent material serves as a
support or carrier for the film of carbon and prevents the destruction of the same.
The substratum or carrier has the properties of non-fusibility and non-conductivity
and is heated up by the intense heat of the current, so as to form a luminous body,
the light of which does not appear, where the carrier is entirely covered with
carbon, while it is clearly discernible at that part which is not covered with
carbon.
The large surface of the incandescent film of carbon furnishes a large light-giving
surface and consequently lamps of greater candle power than can be furnished by
lamps with carbon filaments
If the light giving part D be only partly covered with carbon, as in the case of
suspended lamps, shewn in Fig. 4, the covered portion will emit an intense light

page_text: while the remaining portion will emit a much softer light which is due to the
luminosity or heating-up of this part by the carbon-covered portion. If the lamp
be used for a wall lamp, the front half of the light-giving part is covered with
carbon, so as to emit a strong light in front and a comparatively weak light at
the rear.
If a light of less power is required, the carrier may be covered with a film of
spiral shape as shewn in Fig. 3. The essential advantages of a lamp of this
manufacture or construction will be its comparative freedom from accidental
destruction, its greater economy both as to construction, and light-giving power,
and the higher illuminating power which is capable of being obtained by reason of
the increased light-emitting surface.
In manufacturing the lamp the non-conducting carriers may be covered by the
carbon film by placing them in a pipe through which hydro-carbon gas is passed
the pipe being heated by being placed in a furnace or in other suitable manner.
The gas is thus decomposed and carbon deposited on the carriers; or, the carrier
can be surrounded by a spiral of thin wire without being touched by it. Then the
whole is put into a vessel containing hydro-carbon vapour and a current passed
through the wire to heat the carriers and the gas. A hard deposit of carbon will
now be found on the carrier. Other suitable methods of obtaining a deposit may
be used, as I do not claim or bind myself to any special mode.
Having now described the nature of the said invention as communicated to me
from abroad and the manner of performing the same, I would have it understood
that what I claim on behalf of the said Alex Bernstein is.
Firstly. In an electric lamp based on the principle of incandescence a light-giving
part composed of a non-conducting and infusible carrier and of a film or deposit of
carbon covering partly or entirely the surface of the carrier, substantially as set
forth.
Secondly. In an incandescent electric lamp the combination of the conducting
wires fitted with enlarged end clamps, with, and to support the infusible and
non-conducting carrier covered or partly covered with the carbon deposit
substantially as set forth.
In witness whereof I the said Frederic Des Voeux have hereunto set my hand
and seal this thirteenth day of October, in the Year of Our Lord one
thousand eight hundred and eighty two.
F. DES VEUX. (L.S.)