Improvements in and relating to the Manufacture and Repair of Incandescent Electric Lamps.
Year: 1899

page_text: Date of Application, 2nd Nov., 1899
Complete Specification Left, 3rd Sept., 1900-Accepted, 1st Feb., 1901
Improvements in and relating to the Manufacture and Repair of
Incandescent Electric Lamps.
I, FERDINAND FANTA, of 11, Ironmonger Lane, in the City of London, Con-
sulting Engineer, do hereby declare the nature of this invention to be as
follows:-
The object of this invention is to provide means of increasing the life of
electric incandescent lamps by renewing or regenerating the incandescent fila-
ment of the same, when their efficiency has become too low, thus reducing the
original outlay or cost of those lamps to a considerable extent.
As is well known, the passage of current through the filament results in a
part of such filament volatilizing, the particles of carbon thus volatilized attaching
to the inner surface of the bulb, whereby the same is obscured, whilst the resis-
tance of the filament is increased considerably. The lighting efficiency of the
lamp thus decreasing rapidly, the same has soon to be discarded altogether.
I am aware that attempts have been made to use the bulbs of such "burnt
out" or spent lamps over again, but in all instances the inventors have sug-
gested the withdrawal of the old filament. It is obvious that this is a costly,
and in most instances, more difficult process than the manufacture of the original
lamp, and the principle is moreover at fault, as shown by the following con-
siderations which I have ascertained experimentally.
It has hitherto been believed that the whole body of the filament volatilizes or
burns away, and loses in value in regard to its transmitting and lighting effi-
ciency, and that the core, so to say, of the filament is destroyed, but I find that
this is not the case, but on the contrary, that the core or body of such filament
is, after having been in use for several hundred hours, in a far better condition
than when originally inserted into the lamp. This is accounted for by the fact
that the original carbonizing process, which the filament has to undergo before
its insertion into the bulb, is performed too rapidly; and further, that the process
known as the "reinforcing" or flashing" of the filament is carried out under
unsatisfactory conditions, and these conditions are in most instances, entirely at
variance with those under which such filament comes into use in the finished
lamp.
"
The result of this, is that when used, as it is in actual practice, in a more or
less perfect vacuum, and owing to the atmospheric air (which is still retained or
imprisoned in the pores of the filament) becoming available for combustion, the
outer coating of carbon of such filament slowly combines with the same, and
the CO vapours thus formed deposit on the inner surface of the glass bulb, which
acts in the fashion of a condenser.
In order to again render serviceable an electric incandescent lamp which has
reached the above described stage, it is therefore indispensable, firstly: to free
the bulb of such carbon deposit, and secondly to redeposit carbon on the partly
"burnt" or spent" filament. The object of this invention is to accomplish
"

page_text: both these operations without removing the filament from the lamp, and con-
sequently without interfering with the bulb, seal, or the capping of the lamp.
For carrying out the invention I first of all remove or cut away the small
protruding point of glass formed on the bulb of the lamp, as originally made
when the tube, by which the vacuum has been made therein, is removed by
means of the blow pipe, and I fix into the bulb, instead of the point just broken
off, a small glass tube from 4 to 6 inches long. I hereafter heat the bulb out-
wardly to such a degree as may be necessary to burn the carbon deposited on its
inner surface, and this operation is facilitated by my causing previously heated
air to circulate freely in the bulb, whilst simultaneously drawing off the gases
resulting from the combustion by means of a pump or of any other aspirating
apparatus.
The tube which I use for the above purpose is preferably so arranged that it
carries an inner tube, the extremity of which is long enough to reach that part
of the bulb diametrically opposite to the portion of the bulb into which the outer
tube is jointed. The inner tube is then used for the introduction of the atmos-
pheric air, whilst the outer tube is connected to the pump and provides means
for withdrawing the gases resulting from the combustion of the carbon deposit.
After a short period of application of this cleansing process, the glass of the bulb
appears quite clear and free of the carbon. The bulb is now ready, and the
process of depositing carbon on the filament can be proceeded with.
For this purpose, having created as perfect a vacuum as possible in the bulb,
I introduce into the bulb a gaseous hydrocarbon (such as gasified hydrocarbon,
or more conveniently purified coal gas) with an admixture of a certain quantity
of free atmospheric air, the proportion or percentage of which varies in accor
dance with the size of the bulb and with the voltage and the candle power of the
filaments to be treated, as stated hereunder I then pass the electric current
through the filament. The introduction of the gaseous admixture can be effected
by means of the above referred to inner tube, and the withdrawal of the gases,
resulting from the slow combustion brought about by the incandescence of the
filament, resulting from the passage of the electric current, is effected by means
of the pump; the pressure of the gaseous mixture in the bulb being carefully
regulated and maintained by means of adequate pressure-regulating valves, or
other automatic devices, it being essential to the success of the process, that such
pressure be adjusted to the voltage to the candle power of the filament. as also
to the size of the containing bulb.
As a result of this process carbon deposits on the filament and it is obvious the
resistance of the same diminishes whilst the candle power increases.
Since on the other hand the object is to restore the carbon filament to its
original smaller resistance and higher candle power, I begin my operation with
a variable resistance inserted in the outer circuit, and I gradually increase this
outer resistance simultaneously with the deposit of carbon upon the filament,
and use a photometer for the purpose of standardizing the required lighting
efficiency of the re-inforced filament with a required voltage of current. I stop
the operation when the voltage and the candle power, indicated by the instru-
ments, have reached the desired point, viz.when the resistance and candle
power of the filament has been brought back to their former value in the original
lamp.
Allowance, should, however, be made for the fact that the resistance of their
filament, when in vacuum, is less than that of the filament immersed in the
gaseous mixture, and consequently the normal voltage of the finished lamp will
he lower than that appearing during the time of finishing or "flashing" the
same in the gaseous mixture. When the process has been completed to this
point the bulb is exhausted and sealed in the usual well known manner.
I find that the proportion of atmospheric air of the gaseous mixture which is
important to prevent deposit of carbon on the glass should vary from 3
to 10 per centum according to the size of the bulb and to the nature of the

page_text: filament to be "flashed," the per centage of air being smaller for filaments of
low candle power than for filaments of higher candle power. The quantity of
air used is also dependent on the efficiency of the pump used, viz. the propor-
tion of air forming part of the gaseous mixture may be smaller when powerful
pumps (pumps which are capable of drawing off large bulks of gases) than
when less powerful pumps are used.
The pressure of the gaseous mixture may vary from 4 to 15 m/m according
to the dimensions of the bulb and of the filament. Filaments of low candle
powers and high resistance require more pressure than those of high intensities
and low resistance. The same filaments will require less pressure when treated
in a large than in a smaller bulb.
I further wish it to be understood that since the present invention supplies
means to "flash" the filament in the actual bulb in which it is to be used owing
to my preventing sooty carbonaceous matter from being formed and depositing
on the containers during the "flashing" process (owing to my using an appro-
priate per centage of atmospheric air) this process would advantageously replace
the mode of finishing or "
flashing" the filaments previous to their insertion into
the bulb of the lamp, and also that the simultaneous use of the photometer as
described herein provides means not only of ascertaining and adjusting the
efficiency of the filament most accurately but also, and this is most important, to
reduce to a very large extent, if not to do away altogether with. the large
percentage of odd voltages" of the lamps, as now resulting from the mode of
manufacture commonly used by incandescent electric lamp makers.
Dated this 2nd dor of November 1800
FELL & JAMES,
Agents for the Applicant, 1, Queen Victoria Street, London, E.C.
Improvements in and relating to the Manufacture and Repair of
Incandescent Electric Lamps.
I, FERDINAND FANTA, of 11, Ironmonger Lane, in the City of London, Con-
sulting Engineer, 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:—
Or
The object of this invention is to provide means, and to define a mode of
treatment, for increasing the life of electric incandescent lamps, by renewing
regenerating the incandescent filaments of the same when their efficiency has
become too low, thus reducing the cost of maintenance or replacing of those
lamps to a considerable extent. The treatment in part for reinforcing or flashing
new filaments is obviously also applicable to the manufacture of new lamps.
As is well known, the passage of current through the filament, results in a
part of such filament volatilizing, the particles of carbon thus volatilized attaching
to the inner surface of the bulb, whereby the same is obscured whilst the resis-
tance of the filament is increased considerably. The lighting efficiency of the
lamp thus decreasing rapidly the same has to be discarded altogether.
65
"
I am aware that attempts have been made to use the bulbs of such "burnt
out" or spent lamps over again, but in all instances the inventors have sug-
gested the withdrawal of the old filament. It is obvious that this is a costly
and, in most instances, more difficult process, than the manufacture of the original
lamp, and the principle is moreover at fault, as shown by the following con-
siderations, which I have ascertained experimentally.

page_text: It has hitherto been believed that the whole body of the filament volatilizes or
burns away, and loses in value in regard to its transmitting and lighting effi-
ciency, and that the core, so to say, of the filament is destroyed; but I find that
this is not the case, but on the contrary, that the core or body of such filament
is, after having been in use for several hundred hours, in a far better condition
than when originally inserted into the lamp. This is accounted for by the fact
that the original carbonizing process, which the filament has to undergo before
its insertion into the bulb, is performed too rapidly; and further, that the process
known as the "reinforcing" or flashing" of the filament, is carried out under
conditions, which are, in most instances, entirely at variance with those under
which such filament comes into use in the finished lamp.
"
6
The result of this is that the filament when used, as it is in actual practice,
may probably be working under a strain for which it was not prepared, and the
tendency for the generation of carbon vapours from the filament, and the conse-
quent obscuration of the inner surface of the globe, is thereby much increased
In order to again render serviceable an electric incandescent lamp, which has
reached the above described stage, it is therefore indispensable, firstly:-to free
the bulb of such carbon deposit, and secondly to redeposit carbon on the partly
"burnt." or spent filament. The object of this invention is to accomplish
both these operations without removing the filament from the lamp, and con-
sequently without removing the bulb, or interfering with the seal of the ter-
minals. or the capping of the lamp.
"
"
And in order that mv invention may be the better understood I now proceed to
describe the same with reference to the drawings hereto annexed and to the
letters and figures marked thereon.
Fig. 1 is a vertical section through a lamp fixed in my appliances for regen-
erating or re-inforcing the filament.
Fig. 2 is a general elevation of a battery of such lamps.
Fig. 3 is a diagrammatic elevation of the whole plant used for such regenera-
tion or re-inforcement.
For carrying out the invention when dealing with old lamps I first of all
remove or cut away the small protruding point of glass formed on the bulb of
the lamp (as originally made, when the tube, by which the vacuum has been
made therein, is removed by means of the blow pipe.) and I fix into the bulb,
instead of the point just broken off, a small glass tube a from four to 6 inches
long or may otherwise prepare the open mouth of the bulb for attachment to a
holder. I hereafter heat the bulb outwardly to such a degree as may be neces-
sary to burn the carbon deposited on its inner surface, with a supply of air
thereto. and this operation is facilitated by my causing previously heated air or
oxygenized air to circulate freely in the bulb, whilst simultaneously drawing off
the gases resulting from the combustion, by means of a pump or of any other
aspirating apparatus.
The tube a, which I use for the above purpose, is preferably so arranged that
it carries an inner tube i, the extremity of which may be of desired shape, and is
long enough to reach that part of the bulb diametrically opposite to the portion
of the bulb into which the outer tube is jointed. The inner tube 2, connected by
a packing e and gland to a two way cock f h with a plug d, is then used for the
introduction of the atmospheric air, whilst the outer tube a is connected by a
packing band gland b¹ to an upper body c, having a side exit controlled by a
cock a leading to a pump 1; which provides means for withdrawing the gases
resulting from the combustion of the carbon deposit. After a short period of
application of this cleansing process, the glass of the bulb appears quite clear
and free of the carbon. The bulb is now ready and the process of depositing
carbon on the filament can be proceeded with either for old or new lamps.
For this purpose, having created as perfect a vacuum as possible in the bulb,
I introduce into the bulb a gaseous hydrocarbon (such as gaseous vapour taken
from a liquid hydrocarbon, or more conveniently any purified hydro-carbon gas)

page_text: with an admixture of a certain quantity of free atmospheric air, the proportion
or percentage of which varies in accordance with the size of the bulb and with
the voltage and the candle power of the filament to be treated, as stated here-
under. I then pass the electric current through the filament. The introduction
of the gaseous admixture can be effected by means of the pump having an
alternative suction controlled by cocks and s, one taking hydrocarbon gas and
the other air, the relative percentage of which can be adjusted by the cocks
and s.
The mixed gas and air is then passed to a gasometer m through a heating
coil, a pressure controlling cock or valve K, and through the inner tube i, to
the bulb; and the withdrawal of the gases, resulting from the slow combustion
brought about by the incandescence of the filament caused by the passage of the
electric current, is effected by means of the pump, the pressure of the gaseous
mixture in the bulb being carefully regulated and maintained by means of
adequate pressure regulating valves or cocks K, K', or other automatic devices, it
being essential to the success of the process that such pressure be adjusted to the
voltage, and to the candle power of the filament, as also to the size of the con-
taining bulb.
As a result of this process. carbon deposits on the filament, and it is obvious
the resistance of the same diminishes, whilst the candle power increases.
Since, on the other hand, the object is to restore the carbon filament where
deteriorated to its original smaller resistance and higher candle power, I begin
my operation with a variable resistance inserted in the outer electrical circuit,
and I gradually increase this outer resistance simultaneously with the deposit of
carbon upon the filament, and use a photometer for the purpose of standardizing
the required lighting efficiency of the reinforced filament with a required voltage
of current. I stop the operation when the voltage and the candle power indi-
cated by the instruments have reached the desired point, viz.-when the resis-
tance and candle power of the filament have been brought back to their former
value in the original lamp or to the required standard in new lamps.
Allowance should, however, be made for the fact that the resistance of the
filament, when in vacuum, is less than that of the filament immersed in the
gaseous mixture, and consequently the normal voltage of the finished lamp will
be lower than that appearing during the time of finishing or "flashing" the same
in the gaseous mixture. When the process has been completed to this point the
bulb is exhausted and sealed in the usual well known manner.
I find that the proportion of atmospheric air in the gaseous mixture (which is
important to prevent deposit of carbon on the glass) should vary from 3
to 10 per centum according to the size of the bulb, and to the nature of the fila-
ment to be " flashed," the per centage of air being smaller for filaments of low
candle power than for filaments of higher candle power. The quantity of air
used is also dependent on the efficiency of the pump used, viz. the proportion
of air forming part of the gaseous mixture may be smaller when powerful pumps
(pumps which are capable of drawing off large bulks of gases) than when less
powerful pumps are used.
The pressure of the gaseous mixture may vary from 4 to 15 m/m according
to the dimensions of the bulb and of the filament. Filaments of low candle
powers and high resistance require more pressure than those of high intensities
and low resistance. The same filaments will require less pressure when treated
in a large than in a smaller bulb.
I further wish it to be understood that since the present invention supplies
means to "flash" the filament in the actual bulb in which it is to be used, owing
to my preventing sooty carbonaceous matter from being formed and depositing
on the containers during the "flashing" process, (owing to my using an appro-
priate percentage of atmospheric air) this process would advantageously replace
the mode of finishing or "flashing" the filaments previous to their insertion into
the bulbs of new lamps, and also that the simultaneous use of the photometer,
as described herein, provides means not only of ascertaining and adjusting the

page_text: efficiency of the filament most accurately, but also, and this is most important, to
reduce to a very large extent, if not to do away altogether with, the large
percentage of odd voltages" of the lamps, as now resulting from the mode of
manufacture commonly used by incandescent electric lamp makers.
Having now particularly described and ascertained the nature of this said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1st. The process for the manufacture and repair of incandescent lamps, con-
sisting of the re-inforcement when new or the regeneration when old of the
filament within the bulb by the deposition on the said filament of a coating of
carbon, whilst the said filament is scaled and fixed in the glass bulb in which it
is eventually to be, or has been formerly, used, substantially as herein set forth.
2nd. In a process for the regeneration or flashing of filaments in situ in their
working bulbs, the use of and mode of applying an admixture of vapours of
liquid or gaseous hydrocarbons with atmospheric air (in suitable and variable
proportions & pressures) in the flashing of filaments of incandescent lamps
within their working bulbs according to the voltage or candle power of the
filaments and to the size of the bulbs, substantially as described.
3rd. In a process for the regeneration or flashing of filaments in situ in their
working bulbs, the regulation by means of pressure controlling valve or cocks,
upon the entry and exit respectively, the pressure of the gaseous mixture used
in the flashing of incandescent filaments according to the voltage or candle
power of the same, and in accordance with the size of bulb, substantially as
described.
4th. In a process for the flashing or regeneration of filaments in situ in their
working bulbs, the simultaneous use of a photometer, substantially as and for
the purpose set forth.
5th. In a process for the regeneration or flashing of filaments in situ in their
working bulbs, the means for introducing an admixture of gaseous hydrocarbons.
with atmospheric air, into, and withdrawing same in a continuous stream from,
the said bulbs, at two diametrically opposite points in the bulb for the purpose
of securing a regular distribution of the gases in the bulb, substantially as
described.
:
6th. In a process for the regeneration or flashing of filaments in situ in their
working bulbs, the cleaning the inside of the bulbs of incandescent electric:
lamps from the deposit of carbon, which may have accumulated thereon during
use, or in the process of manufacture, by heating such bulbs externally, whilst
introducing air heated or oxygenized into the same, and simultaneously there-
with, withdrawing the products of combustion, substantially as and for the
purpose set forth.
7th. In a process for the manufacture of incandescent electric lamps, the
cleaning of the inside of the bulb from any obscuring deposit of carbon thereon,
by the application of external heat with simultaneous access thereto of air or its
equivalent substantially as described.
1
FELL & JAMES,
1, Queen Victoria Street, London, E.C., Agents for the Applicant.