Improvements in Incandescible Materials and Mantles and the Process of Making the same.
Year: 1897

page_text: Date of Application, 2nd Oct., 1897-Accepted, 4th Dec., 1897
COMPLETE SPECIFICATION.
Improvements in Incandescible Materials and Mantles and the
Process of Making the same.
I, WILLIAM LAWRENCE VOELKER, 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 Incandescible Materials and Mantles
and the Process of Making the same.
The invention particularly aims to improve the character or color of the light
emitted when the mantles are heated over non-luminous flames; also to increase the.
durability of the mantles, which as usually made, are very frail and lacking in tensile
strength.
The invention is operated as follows: The combustible thread or carrier for the
decomposable salts which form the finished mantle is first carefully cleansed of
impurities in the manner well known to chemists, and after cleansing is dried,
shrunk and knitted into long tubes. These tubes are then saturated with a
twenty-five per cent. solution of commercial thorium nitrate or other salt,. the
oxide of which will emit white light when heated to incandescence. After the
saturation, the tubes are well drained' of surplus solution, then transferred to a
centrifugal drier and the balance of the moisture removed from them, and finally are
carefully dried in a drying room at a temperature of about 120° F.
When thoroughly dried the tubes are cut in pieces of suitable length to form
mantles. One end of each piece is turned in and sewed with a thread which has
been treated with the solution, and this end is then gathered in by an asbestos thread,
which is tied to form a loop to suspend the mantle by.
The tube or stocking, as it may now be called, is then shaped on a suitable
former, and is next burned off in the well known manner over a bunsen flame. The
result is a skeleton or framework of the oxide of the mineral whose nitrate was
employed in solution.
This framework or skeleton is next dipped in an alcoholic solution of the combined
nitrates of calcium and magnesium. This solution is formed by decomposing
combined oxide of calcium and magnesium in nitric acid, and using one part by
weight of the dry salt (nitrate) to three parts by weight of alcohol to form the
alcoholic solution.
After thus dipping, the framework is again burnt off over a Bunsen flame, the
nitrate of calcium and magnesium being thereby decomposed to the combined oxide
of calcium and magnesium, and the result is a mantle composed of a mineral
oxide framework completely covered with or embedded in a coating of combined
oxide of calcium and magnesium. I can, for certain uses of the mantle, give a
second and even a third coat of my material with good results, the richness and depth
of the light increasing with these additional coatings.
Besides improving the light-giving power of the mantles the coating of my
combined oxide of calcium and magnesium greatly increases the strength, hardness
and durability of the mantles, so that they can be handled with only ordinary care
without injury.

page_text: After the mantles have been made as hereinafter described, they may be coated
with a coating composed of alcohol, aether, photoxylin, (a chemically pure soluble
cotton) celluloid solution and excess of camphor, or they may be covered with any
other suitable coating.
It is evident that various steps in the operations hereinbefore described may be
changed without essentially changing the invention. For example, instead of
saturating long tubes in the first solution, the tubes could be cut into pieces and the
pieces saturated. Also other modes of drying the tubes after they are saturated can
be employed in place of that herein mentioned.
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:
1. An incandescible material composed of an oxide of the rare mineral earths
coated with the combined oxide of calcium and magnesium, substantially as
described..
2. An incandescible material consisting of thorium oxide coated with the combined
oxide of calcium and magnesium, substantially as described.
3. The process of manufacturing incandescible structures consisting in saturating
a combustible fabric with a decomposable salt of the rare mineral earths, burning
out the fabric and decomposing salt to an oxide, and then coating the resulting
framework with the combined oxide of calcium and magnesium, substantially
as described.
4. The process of manufacturing incandescible structures, consisting in saturating
a combustible fabric with a decomposable salt of thorium, burning out the fabric
and converting said salt into oxide of thorium, and then coating the resulting
framework with the combined oxide of calcium and magnesium, substantially as
described.
5. A mantle consisting of a framework of oxide of thorium covered with the
combined oxide of calcium and magnesium, substantially as described.
Dated this 2nd day of October 1897.
S. S. BROMHEAD,
171, Queen Victoria Street London E.C:, Patent Agent.