Hoods, Mantles, or Gratings for Incandescent Gas-lights.
Year: 1896

page_text: Date of Application, 16th June, 1896-Accepted, 18th July, 1896
0
COMPLETE SPECIFICATION.
Hoods, Mantles, or Gratings for Incandescent Gas-lights.
I, WILLIAM LAWRENCE VOELKER, of Elizabeth, in the County of Union,
State of New Jersey, U.S.A., Electrician, do hereby declare the nature of my
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 hoods, mantles or gratings for incandescent gas-lights.
In particular, it relates to the filaments of which such hoods, mantles or gratings
are constructed, and it is the aim of this invention to produce a filament having
such tensile strength that it can be readily handled by ordinary weaving or
braiding machinery,
The incandescing material of which the core of the filament is composed may be
made in any known manner, as for example by combining any of the suitable
incandescing oxides of the rarer metals, or oxides of magnesium and calcium with
a viscous material. The subject of this application is however, not the incandescing
core per se, but the reinforcing or protecting of any incandescing filamentary core
by a suitable envelope of fibrous combustible material.
The filament or core of the incandescible material itself has considerable tensile
strength, yet it cannot be handled so roughly as is required by ordinary weaving
or braiding machinery in the operation of constructing mantles, without risk of
being broken. I have, however, invented a means of greatly increasing the tensile
strength of the thread.
I proceed in the following manner :-
When the thread or fibre of incandescible material is sufficiently dry, it is
covered with a thin cotton braid, or it may be covered as some wires used in
electrical work are by right and left hand spiral winding. I may also run several
strands of cotton yarn, or other combustible fibres, along the thread or filament of
the incandescible materials, and then run the cotton cover on spirally, and in this
way I greatly increase the tensile strength of the filament.
The mechanical strain produced by the braiding or weaving machinery is taken
up by the cotton covering which is placed on the filament in the manner just
before described, and the hood, mantle, or grating braided or woven with the
fibrous thread of this character will, when baked have loose contact joints, while
the fibrous covering does not interfere with the contraction during baking, but does
preserve the elasticity of the thread a long time.
Although the joints of the hood or mantle are loose as above explained, yet
after baking, the mantle will preserve its shape, for, first, after baking, the
filaments acquire a certain hardness and elasticity which preserves them in their
original form of spirals, and, secondly, while the mantle is capable of being com-
pressed vertically, yet when suspended from a rod at the top in the usual manner,
its weight opens it vertical to a certain degree, which determines the normal height
of the mantle. Thereafter its dimensions vary only within the narrow limits of its
contractions and expansions.
An important result of covering the filaments with the case or sheath of
combustible material is, as above indicated, that the filaments do not stick
together at the points where they cross or interlace, but remain free. Therefore,
when the covering is burned out I have a hood composed of filaments each of
which is free to expand and contract without exerting strain on the other filaments

page_text: or being strained by them, and the durability of the hood is, in this manner,
materially increased.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. A filament for incandescent gas-lights, composed of a core of incandescible
materials and a casing of fibrous combustible material.
2. A hood, mantle or grating for incandescent gas-lights, woven or braided with
threads which consist of filamentary incandescible materials covered by an envelope
of fibrous combustible materials.
Dated this 16th day of June 1896.
S. S. BROMHEAD,
97 Newgate Street, E.C., Patent Agent.