Improved Process for Manufacturing Durable Incandescent Gas Mantles.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improved Process for Manufacturing Durable Incandescent Gas
Mantles.
I, HANS HELMECKE, of Jungmannstrasse 25, Hamburg, in the Empire of Germany,
Engineer, do hereby declare the nature of this invention to be as follows:-
For several years attempts have been made to improve upon Auer's invention of
manufacturing incandescent mantles of oxides of earth metals, wherein it was tried
to harden the mantles and render them more durable, partly by modified chemical
composition of the ingredients, partly by exterior influences to which the mantles were
subjected. But all these attempts failed more or less to fulfil their purpose on
account of the circumstance that the augmented durability and strength could only
be obtained at the expense of their brightness and illuminating capacity.
Whilst at the present time the manufacture of good mantles is almost exclusively
effected from a mixture of about 99 per cent. of thorium oxide and about 1 per cent.
oxide of cerium which greatly excel all other products with respect to their illuminating
effect; the present process is entirely different rendering it possible to produce a
mantle of at least the same illuminating intensity but of far greater durability
without the use of cerium or thorium.
This is done by use of a mixture of calcium oxide with the oxides of certain earth
metals as for instance lanthanum, zirconium and yttriuin. Pure oxide of calcium is
known as one of the most fire proof materials and gives at suitably high temperatures
an intense white light whose spectrum is near to that of the light from electric are
lamps. For producing incandescent gas mantles for normal Bunsen burners it is
however not practicable as shown by several experiments made for this purpose
because it needs too much heat to bring it to the necessary state of incandescence
and as well alone, as in connection with most of the other substances in question it is
liable to contract or "retreat." These essential disadvantages to the use of calcium
oxide for lighting purposes are entirely avoided in the present method; the light
radiating power of the incandescent mantles of my invention arranged on ordinary
Bunsen burners is excellent, the color of the light varying according to the compo-
sition of the chemical ingredients from white to gold white and the mantles are
durable without prejudice to their elasticity. Moreover the mantle does not break or
scarcely so even after a long use.
The process of impregnating the cotton or silk fabrics, the drying, singing and
forming and hardening is the same as in the hitherto used methods.
Nitrates being soluble in water and the acid burning away easily with the organic
fabric of the mantle, leaving the aforesaid oxides, the following solutions, for instance,
produce very good results:"

page_text: These essential disadvantages to the use of calcium oxide for lighting purposes are
entirely avoided in the present method; the light radiating power of the incandescent;
inantles of my invention arranged on ordinary Bunsen burners for normal pressure
and gas consumption is excellent; photometric measurements showing an intensity
of light equal to 60-70 Hefner candles. The color of the light can be modified as
desired according to the composition of the chemical ingredients, from bluish white,
pure white, to golden white. Durability of structure attained without prejudice
to elasticity. Moreover the mantle contracts far less even after a long use than the
mantle made of cerium or thorium oxide.
The process of impregnating the cotton, silk or the like fabrics, the drying,
incinerating, forming and hardening over the gas flame is analogous to the hitherto
used methods.
It may be mentioned that mantles of calcium oxide and other metals hereinafter
mentioned after incineration (although calcium oxide is in molecular mixture with
the oxides of the earth metals) are not hydroscopic.
The following solutions for instance produce very good results:-
The color of the light from mantles made with the third solution in this Specifi-
cation is given as pure white, but if the lanthanum used is not pure but contains
races of didymium or cerium the color of the light would be "gold white" as given
n Provisional Specification.
Having now particularly described and ascertained the nature of the said
nvention and in what manner the same is to be performed I declare that what
I claim is :-
1. The production of incandescent gas mantles from the oxides or salts of the