Glow Bodies for Incandescent Gas Lighting.
Year: 1896

page_text: Date of Application, 28th Jan., 1896-Accepted, 4th Apr., 1896
COMPLETE SPECIFICATION.
Glow Bodies for Incandescent Gas Lighting.
I, CHARLES KORTWICH of Scharrenstrasse, Berlin, Germany, Merchant, 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 glow or incandescent bodies hitherto employed for incandescent gas
lighting present the disadvantage of a relatively slight capacity of resistance to
shocks and also after long use, of giving a light of greatly diminished intensity.
I have found that the great liability to fracture of the glow bodies hitherto
employed for different systems consists in their fully amorphous condition, whilst
the sensitiveness of the same to atmospheric dust is due to the circumstance that
the oxides used in said glow bodies enter into comparatively readily melting
combination with the elements contained in the dust whereby the illuminating
capacity of the glow bodies is diminished.
The object of the invention is to suppress the said disadvantages by the employ-
ment of a combination of substances possessing on the one hand a crystalline
structure, that is to say, a structure in which the crystals passing through the
body of the material possess the property of increasing the inner cohesion of the
glow body and on the other hand the property of not readily entering into
combination with the bodies contained in the dust.
I have found that the said advantageous properties are possessed in a high
degree by a number of substances. These are boron, arsenic and antimony in the
form of borates, arseniates and antimoniates of the alkaline earths, earths and
precious earths, by which latter is meant those elements which in watery
solution possess unstable sulphides and whose hydrates are insoluble in ammoniacal
solution.
Whilst the borates rich in boric acid readily melt in glowing heat such is not
the case with borates poor in boric acid.
The arsenical acid combinations of the alkaline earths, earths and precious
earths are thoroughly constant and are characterised by a high illuminating
capacity. As now the atmospheric dust contains in bases, in conjunction with
the volatile alkalies in the heat, mostly alkaline earths and these in combination
with arsenical acid enter with difficulty into melting combinations, the glow bodies
made from the arseniates of the aforesaid substances are not in any way affected
by an external influence of this kind.
The antimoniates of the aforesaid substances are characterised in a very high
degree by firmness illuminating capacity and resistance to external influences.
In all the above mentioned cases it is understood that borates, arseniates and
antimoniates of high basicity are employed, as highly basic combinations, like
glass poor in silicate and rich in basicity, are melted with much greater difficulty,
than those rich in silicate. If the former are once placed in the state of chemical
combination they will possess great hardness and capacity for resistance.
In the production of the glow bodies of this invention I employ the well known
process described and carried out. by Williams in accordance with his Patent
Specification No. 225 of 1882 and by others, of the saturation of combustible
absorbent bodies with salt solutions or emulsions, with subsequent burning away of
the combustible foundation body.

page_text: The following is an example of my glow body combinations or compounds in
the form of a solution serving for the impregnation :-
Thorium nitrate
Lanthanum nitrate
Cerium nitrate -
Yttrium nitrate
Chloride of antimony
Zirkon nitrate
Pyrotartaric acid-
Water
22.25 parts
2.75
1.50
0:35
$1
0.75
"
2:00
"
2.00 "
70.00 "
lustead of the chloride of antimony another salt of antimony soluble in water
may be employed or boric acid or chloride of arsenic or another arsenical salt
soluble in water.
Instead of the combination given above the other alkaline earths, earths and
precious earths may also be employed in other proportions of the mixture, for
example pure, and even weak, impure thorium, possesses a high illuminating
property in the combination as borate, arseniate or antimoniate.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be perforined, I declare that what
I claim is:-
Glow bodies for incandescent lighting produced from (a) borates (b) arseniates
(c) antimoniates of the alkaline earths, earths and precious earths, substantially as
described.
Dated this 28th day of January 1896.
THOMAS R. SHILLITO,
89 Chancery Lane, London, W.C., Agent for the Applicant.