Improvements in the Manufacture of Incandescence Mantles or Bodies for Illuminating Purposes, and in Material for Use in such Manufacture
Year: 1898

page_text: Date of Application, 5th Dec., 1898-Accepted, 29th Apr., 1899.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Incandescence Mantles or
Bodies for Illuminating Purposes, and in Material for Use in such
Manufacture.
I, WILLIAM LAWRENCE VOELKER, of 133, West Jersey Street, Elizabeth, New
Jersey, State of New Jersey, United States of America, Electrician, 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:
This invention relates to improvements in the manufacture of incandescence
mantles, hoods or bodies for illuminating purposes and to an improved material
for use in such manufacture.
In the Specifications of former Letters Patent granted to me and dated
4th August 1896 No. 17,194 and 2nd October 1897 No. 22,625, I have described
the production of a material which I term "Magnesium Calcite," and which is
now known and sold under the name "Voelkerite."
"
One feature of my said invention is the employment, for coating an incandescence
body or skeleton composed principally of thorium oxide, of an alcoholic solution
of the Voelkerite " or combined oxide of calcium and magnesium, consisting of
about ten per cent. of "Voelkerite" and ninety per cent. of alcohol.
Another feature of my said invention consists in dipping the aforesaid in-
candescence body or skeleton into the solution of light-emitting material with its
upper end downward so that it will be more thickly coated at or near the top than
at or near the base, and will therefore be more durable and less fragile and capable
of emitting a better light than it would be if dipped in the usual way.
46
Practical experience has shown the following composition of Voelkerite" to
give the best results, viz. :-

page_text: several oxides constituting the "Voelkerite " are mixed in or about in the above-
named proportions, and the material thus formed is dissolved in the alcohol in
the proportions stated.
I have further found that the strength, elasticity and durability of the mantle
are considerably enhanced by dipping the thorium skeleton in the alcoholic
solution upside down instead of in the usual way.
The percentage of "Voelkerite" can advantageously be increased to about
20 per cent. if a higher candle-power than usual is required.
The effect of the dipping upside down is the following:
The light-emitting coating which is formed by the "Voelkerite" and which
entirely surrounds the thorium skeleton and intimately adheres to it in the same
way as the coating in plated metal, increases in thickness from the bottom of the
mantle upwards, so that the greater mass thereof is near its top or point of
suspension, which always has been the weakest part of the mantle heretofore, and,
as the result of this improved method of dipping, a mantle is obtained which is
strong but flexible at the bottom and gradually increasing in strength and rigidity
towards the top.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
-
First. In making an incandescence mantle or body, the employment of a solution
of "Voelkerite" in alcohol in the above-named proportions as a light-emitting
coating for a thorium oxide mantle-skeleton.
Second. The dipping of the mantle-skeleton in the solution of light-emitting
material with its upper end downward so as to ensure a thicker deposit of the said
material at or near the top than at or near the base of the mantle.
Third. An incandescence mantle or body consisting of a skeleton composed
principally of thorium oxide and having a coating of light-emitting oxides which
increases in thickness from the base of the mantle upwards, substantially as
hereinbefore described.
Fourth. The herein described improved material or "Voelkerite" for use in
the manufacture of incandescence mantles or bodies, in which the several oxides
are mixed in or about in the above-named proportions.
Dated this 5th day of December 1898.
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.