Improvements in Incandescent Gas Lamps.
Year: 1895

page_text: Date of Application, 24th Sept., 1895-Accepted, 23rd Nov., 1895
COMPLETE SPECIFICATION.
Improvements in Incandescent Gas Lamps.
I, WILLIAM LAWRENCE VOELKER, of Elizabeth, in the County of Union,
State of New Jersey, U.S.A., Gentleman, 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 :-
My invention relates to the hoods, mantles, or gratings of incandescent gas
lamps, and which are suspended over and embrace the flame and become
incandescent under the heat thereof.
For successful application of the hoods to illumination it is necessary that the
hoods shall have a small relative mass and a large radiating surface. This is
realized by making the hoods of fine threads or filaments, woven, knitted, or put
together by other mechanical means, to form a net-like structure of the desired
shape. But such a structure is difficult to handle, because heretofore it has had
but little mechanical strength. Only materials which have a very low specific
heat are of any value for the hoods, such for example, as the oxides of the metal,
and preferably those alkalies and the earths proper, so called by chemists.
I have overcome the aforesaid difficulties, and produce a hood having a strength
greatly superior to those heretofore known, by constructing the frame or carrier
of the hoods of porcelain or porcellanous compound, which, when baked, has
considerable strength, and adding to this frame in any suitable manner, as by
impregnation or incorporation therewith, an incandescing substance, bringing the
hood to a hard and refractory condition by baking. Such hoods may be produced
in several equivalent ways, and I will describe two methods which have been
successfully employed by me, the parts of the structure and the process varying
somewhat in each, but each making use of a frame or structure of porcellanous
material with which is compounded an incandescent substance.
One of my methods is as follows: 60 parts kaolin, 20 parts of quartz, and
20 parts feldspar by weight, are ground to an impalpable powder and mixed.
An equal weight of saturated solution of sugar syrup is then thoroughly mixed
with the mass. A mass is thus formed from which threads or filaments of great
tensile strength can be made in any suitable manner as by drawing in a die.
These filaments can be formed into hoods by weaving, knitting, or other suitable
This
mechanical operations to produce the desired shape of the structure.
skeleton structure is then thoroughly dried and baked at a high temperature in a
suitable oven. After this, it is dipped in a strong or saturated solution of salts of
the metals which are to be used for the incandescing properties. The hoods are
then oxidized by the proper chemical agents, heat, or electricity.
I may modify the foregoing process by incorporating the oxides with a
The
porcellanous material while the latter is still in the powdered state.
saccharine matter is added at the same time. In this case I proceed substantially
as follows: 20% of the porcellanous material, reduced to an impalpable powder
as heretofore stated, is combined with 45 parts of light oxide of magnesia, 10 parts
zirconia oxide, 5 parts chromium oxide, and 20 parts of dense sugar syrup by
weight.
These materials are thoroughly mixed and reduced to a mass of the consistency
of putty. Threads or filaments can be formed of this mass as before stated, and
the threads or filaments may be woven or otherwise combined into suitable hoods or
mantles. The hoods are then thoroughly dried and baked in suitable ovens, when
they are ready for use.

page_text: The basic idea of the present invention consists in the forming of a frame or
carrier of porcellanous material to sustain the metallic oxide which constitutes the
incandescing agent. The metals and their proportion may be somewhat varied
without departing from the essence of my invention, and the oxides may be
incorporated with a porcellanous material before the latter is formed into the
desired shape, or by impregnating the carrier afterward as I have described.
The porcellanous carrier gives tensile strength to the hood, and is the vehicle
for holding the incandescing particles; in other words, the porcelain biscuit, which
is to say the porcellanous carrier, being a porous body, is rendered more porous or
cellulous by the oxidizing of the saccharine matter.
In the first process above described, the porous frame work has its coral-like
structure sufficiently covered with myriads of small crystals of the oxides or salts
of the metals, which are held there first by chemical means, then again when
baked by mechanical means. In the second process the porcellanons structure is
still the frame work, the chemical combination, under the influence of heat, taking
place just the same. But in the latter process it is modified by the incorporation
of the oxides of magnesia in such a manner that the shrinkage is not so great at
a given temperature, but after numerous experiments I have demonstrated that
the final result is approximately the same in both processes in respect to light
giving qualities.
I do not claim the use of any of the metallic oxides that become incandescent
at a high temperature, as they are well known to chemical science.
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 porcellanous incandescent gas lamp mantle having a filamentary body or
frame work impreguated by or incorporated with an incandescing substance and
brought to a finished hard and refractory condition by baking.
2. A porcellanized web or woven mantle for incandescent gas lamps.
Dated thin 02nd J... of Santambar 1905
WALLACE FAIRWEATHER,
Chartered Patent Agent,
62 St. Vincent Street, Glasgow, Agent for the Applicant.