Improvements in the Manufacture of Light Emitters or Illuminants for Electric and other Lamps.
Year: 1890

page_text: Date of Application, 14th Jan., 1890
Complete Specification Left, 8th Nov., 1890-Accepted, 14th Mar., 1891
Improvements in the Manufacture of Light Emitters or Illuminants
for Electric and other Lamps.
1, JAMES CLEGG, of Connaught Mansions, Victoria Street, in the City of
Westminster, Gentleman, do hereby declare the nature of this invention to be as
follows:-
The object of this invention is the improvement of illuminants for electric and
other lamps, by encasing or combining them with a metallic compound or metallic
compounds.
I use two kinds of metallic solutions, one being formed by dissolving one or more
oxides of metals or the metals themselves in volatile solvents, and the other by
dissolving or holding in suspension the oxides of metals, or the metals themselves,
in solvents, and mixing the solution with a volatile liquid or liquids.
Having prepared the metallic solutions with or without an additional volatile
liquid, I place any one or more of the liquids in or in connection with a vessel in
which a vacuum can be maintained and suspend the illuminant in the vessel then I
exhaust the vessel of air and if the liquid is not already in the vessel I open it to
the vessel in which the liquid is contained and electrically heat the illuminant, the
result to the illuminant is a deposition thereon of the oxide or oxides, or metal
or metals, which increases its durability. As an example of a solution of oxides 1
would mention the following.
I take the oxide of strontium and dissolve it in a solution of iodine and
absolute alcohol which is effected by adding an excess of the oxide of strontium
until the maximum quantity has been dissolved by prolonged heating in a closed
retort, with exclusion of air.
The bromides and iodides and chlorides will combine with one another and
therefore they may be used in combination but I prefer to use them separately.
The solutions of the oxides of metals or of the metals themselves may also be
combined, and used together in the one solution; or, the oxide or oxides, and metal
or metals, may be combined in the same solution.
Some metallic solutions are better prepared by dissolving the metals themselves
in the solvent or solvents with or without the aid of the volatile liquid, but
generally better results are obtained by dissolving the oxide which is especially
shown with calcia, magnesia, strontia, alumina, baryta, beryllia.
In some cases I take a conductor already coated with oxide and coat it with
a metal or with oxide by the above described process. As for example I take a
conductor coated or impregnated with alumina and coat it with iron thereby
obtaining a compound of alumina and iron on or in the conductor.
The following are examples of metals or their oxides which may be used for the
purposes of this invention-Zirconium, calcium, strontium, barium, beryllium,
magnesium, cadmium, scandium, yttrium, lanthanum, didymium, erbium, aluminium,
manganese, iron, chromium, molybdenum, tungsten, uranium, titanium, thorium,.
vanadium, antimony, niobium, rhodium, ruthenium, osmium, thallium, cerium,
sawarium, terbium, decepium, ytterbium, gallium, indium, palladium, iridium,
platinum.
Thated thio 14th dov of Lanuary 1890

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Light Emitters or Illuminants
for Electric and other Lamps.
I, JAMES CLEGG, of Connaught Mansions, Victoria Street, in the City of
Westminster, Gentleman, 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:-
The object of this invention is the improvement of illuminants such as are
usually employed for incandescent electric lamps by treating them with certain
metallic matters as I shall presently describe, whereby I render them more durable
and also much more efficient, that is to say, capable of giving out a much greater
amount of light from a given expenditure of electric energy, than illuminants which
are not so treated.
In order to carry out my invention, I prepare volatile liquids having suspended
or dissolved in them oxides, salts or compounds of certain metals.
The volatile liquid may be prepared as a vehicle of haloid salts of the metals in
the following manner. I dissolve iodine. in alcohol, or I saturate alcohol with
chlorine and dissolve the metal in this liquid, or I dissolve the metal in bromine
and mix the solution with alcohol. Or oxides of the metals, or salts of the metals,
preferably their compounds with organic acids as for instance magnesium acetate,
are added to alcohol so as to be dissolved, or, if they are not soluble, to be
suspended in a state of fine subdivision in the alcohol. I find these solutions or
mixtures are rendered more serviceable by boiling them for several hours in a
retort communicating with a condenser arranged to return the condensed liquid to
the retort, this condenser being sufficiently cooled to prevent excess of pressure in
the retort. Instead of alcohol, other volatile liquids such as benzine or ether, may
be employed, but alcohol is to be generally preferred as being less expensive and
more effective than many other volatile liquids. Having prepared the volatile
liquid as above described, I put a charge of it in the lower part of a vessel
connected with another vessel in which a vacuum or nearly a vacuum is maintained
by pumping or otherwise. In the vessel containing the liquid, but at some height
above it, I suspend the illuminant which is to be treated. Having exhausted this
vessel of air, and by the reduction of pressure caused vaporisation of the volatile
liquid, which may be aided by the application of external heat, I pass through
the suspended illuminant an electric current sufficient to heat it to incandescence,
and in a very short time I obtain upon it a deposit of some of the metallic matter
which is carried up along with the vapour of the volatile liquid.
Instead of exhausting the air from the vessel by connecting it to a vacuous vessel,
the air may be expelled by boiling the volatile liquid in the vessel, but this involves
certain waste of the liquid and, if the air is not thoroughly expelled, there is some
risk of explosion when the illuminant is heated. Almost any metal may be
employed as above described for treatment of illuminants except those which
become volatilised at the high temperatures to which illuminants are exposed. For
instance zinc, sodium or potassium could not be used.
Metals such as magnesium, calcium, chromium, manganese and many less
generally accessible metals such as zirconium, thorinum, or lanthanum, give the
best results. Some metals which are not applicable alone may be used in
conjunction, for instance iron, which cannot be successfully applied by itself, can be
used in combination with aluminium. Also finely divided silica can be used in the
same manner as insoluble oxides of metals.
The illuminants which I treat as above described may be any of those usually
employed for incandescent electric lamps which are mostly of carbon in various
forms.
The metallic matter deposited on them by my process, if it reaches them in the
form of oxide or salt, may probably be more or less decomposed or reduced by

page_text: contact with the highly heated carbon, or the metal may enter more or less into
combination with the carbon.
Whatever be the chemical result, the illuminant is rendered by the treatment
not only more durable than illuminants which are not so treated, but is also
rendered much more efficient as an illuminant, that is to say, when heated in a
vacuous bulb, by expenditure of a given amount of electrical energy it gives out
much more light as may be understood from the following examples, shewing results
of experiments made with illuminants before and after their treatment by my
process.
A carbon filament which before treatment consumed 4.25 Watts of
electrical energy per candle, after treatment with magnesium iodide consumed only
2.2 Watts per candle. Another filament of different make, which before treatment
consumed 34 Watts per candle, after treatment with magnesium iodide consumed
only 1.77 Watts per candle. I have made many other experiments giving similar
results. I may mention also another result which these experiments have shewn,
namely that illuminants when treated by my process undergo very little change in
their resistance under even extreme variations of temperature, much less change
than illuminants not so treated.
For example I worked illuminants treated by my process with E.M.F. varying
from 40 to 67 volts, giving light varying from 20 to 240 candles, and I found
their resistance varied only from 29.6 to 30.8 ohms.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that I make no general
claim to illuminants for electric lamps consisting of carbonaceous material bare or
encased with refractory metallic oxides, as I am aware that various forms and
compositions of such illuminants have been proposed or used, nor do I claim
generally the depositing of substances from liquids in which they are dissolved or
suspended upon illuminant cores electrically heated when immersed in such
liquids, but what I claim is :-
In the manufacture of light emitters or illuminants for electric lamps, the herein
described treatment causing deposit on them of metallic matter, by electrically
heating them to incandescence while they are suspended in a vessel from which air
is excluded, above a volatile liquid such as alcohol having dissolved or suspended
in it a haloid or acid salt or an oxide of some one or more suitable metals.
Dated this 7th day of November 1890.
ABEL & IMRAY,
Agents for the Applicant.