Improvements in and relating to Incandescent Mantles for Lighting.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in and relating to Incandescent Mantles for Lighting.
I, ADOLF MARTINI, of 81, Leipzigerstrasse, Berlin, in the Empire of Germany,
Analytical Chemist, do hereby declare the nature of this invention to be as
follows:-
My invention relates to the manufacture and use of certain materials in the
production of mantles and the like for incandescent gas lighting.
Mostly all incandescent mantles and like structures are manufactured by the
same process, using a very limited number of elements. Many of these bodies lose
after a short while their original form, as they are all very breakable; and the
duration of them is influenced by the stability of their form, the coagulating or
trickling of the material, and by chemical reactions produced by the flame, as in
carbides and the like. By my invention incandescent mantles can be made of a
superior lasting quality and as well as employing the materials now commonly
used the salts of the following metals may also be used;-Stannum (Sn) potas-
sium (K) sodium (Na) lithium (Li) rubidium (Rb) caesium (Cs). My mantles can
be made by the old way of manufacturing or by another system, which I will
hereinafter describe.
When a mantle contains potassium it will practically preserve its original form
during hundreds of hours use and this is one of the most important points in
incandescent lighting. By experiments it has been found that the usual mantles
give when first used about 70 Hefner candles, but only show 38 candles after
600 hours. It has been also found that the loss does not originate only from
chemical re-actions or trickling of the material, but that the principal cause is
the deformation of the mantle. Such old mantles placed on a different burner, in
which the flame had a varying form from that in the first used burner showed 54
Hefner candles thus proving that the difference of form affects the candle powder.
The trickling and the chemical reactions results as well from the components
of the materials as from the circumstance whether the materials are thoroughly
mixed together or arranged by layers. It is therefore evident that any process
which will produce permanence of form and prevent trickling increases the life and
efficiency of the mantle.
Not only do I attain the object of my invention by different materials, but also
by a new way of gradually arranging several layers of materials important results
are obtained. A mixture of the salts of thorinum with stannum, to which a small
percentage of the rare earths of uranium and platinum and about 2% potassium
are added, produces a mantle not only of a high candle power but of great
stability. More than 20%, stannum makes a mantle useless so that the percentage
must be kept under this. Very hard mantles can be made by solutions of 1 to 22%
cerium nitrate, or by admixture of a smaller or higher percentage of one or more
of the rare earths, or platinum and uranium, and
10/
201

page_text: .8 grammes sodium.
When too much potassium is in a mantle only a certain part will enter imme-
diately into molecular combination, the rest combines only gradually, this being
on the whole advantageous.
To make the hard mantles herein before described elastic, diluted sulphuric acid
is carefully dropped into the solution, though concentrated sulphuric acid cannot
be used as precipitations would result. The manufacture of such mantles is
effected by bringing into solution all or most of the salt impregnating the raw
mantles with it, burning them to ashes and giving by hot air or by flame the
desired form.
As an alternative all materials are worked to fine threads, by placing them in
same easy combustible collodion like media; and therefore in such a case not only
soluble salts but insoluble materials can be used.
A further portion of my invention by which the trickling and the chemical
processes in the flame diminishing the efficiency of the mantle are influenced, is
the following, The mantle affer being formed and containing oxides, is dipped
in a second solution.
This dipping has the effect of coating the threads and depositing on their sur-
face the greatest part of the salts of the second solution, whereas on the inner
parts of the thread only a smaller quantity of it is deposited. To effect this pur-
pose only a-very-thick solution is employed and the whole process in producing
the hoods is as follows,-972% thorinum nitrate is disolved with 2% potassium
nitrate. With such solution the raw mantle is soaked, and after drying burnt
to ashes and formed. This mantle is very hard. The second solution consists of
caoutchouc, gutta percha, and bees wax and of chloroform, benzol and ether,
to which cerium nitrate is added. The cerium nitrate must be mixed with alcohol.
Many other mixtures as well as the following for the skeleton can be made
10 grammes stannum chloride.
87
2
grammes thorinum nitrate or chloride.
grammes potassium nitrate
and for the second solution the cerium can be replaced entirely or partly by other
rare earth as those of uranium platinum, neodym and praseodym.
Didymium together with cerium used in mantles, manufactured by this system
gives out a strong and agreeable tinted light, the supposition, which forbade the
use of cerium in the presence of didymium proves not to be correct.
Dated this 10th day of November 1897
Improvements in and relating to Incandescent Mantles for Lighting.
I, ADOLF MARTINI, of 81, Leipzigerstrasse, Berlin, in the Empire of Germany,
Analytical Chemist, do hereby declare the nature of this invention and in what

page_text: manner the same is to be performed, to be particularly described and ascertained
in and by the following statement; →
This invention relates to incandescent mantles and has for its object to produce
a mantle that shall be stable and durable. The incandescent mantles that have
hitherto been brought into the market have been made according to similar pro-
cesses and by means of a narrowly restricted number of elements. The mantles
heretofore used have generally become deformed or have lost their shape after a
short period of burning and they all are very fragile and brittle.
It is the object of the present invention to secure constancy of illuminating
power by providing a stable mantle in which fusion and chemical re-actions shall
not occur which usually have the effect of lessening the illuminating power.
The invention consists in the production of a mantle by the use of compounds
of potassium, sodium, lithium, caesium, rubidium, and tin, and in a process for
the production of mantles by secondary impregnation as hereafter described.
According to the invention a greater number of elements can be employed
than those generally used and the number of suitable combinations can be increased
whereby greater durability and an extended field of employment of the mantles
are secured.
The salts of the metals potassium, sodium, lithium, caesium, rubidium, and tin,
such as their nitrates, sulphates, chlorates, and acetates are employed. When
potassium is used it has been found that the mantle retains almost completely
its original form which is of great importance in the duration of the intensity of
the light. The experiments that have been conducted by me have shown that
mantles heretofore usually employed having for example an initial illuminating
power of 70 Hefner candle power had after 600 hours of burning only 38 candle
power but it was found that the diminution of the illuminating power was not
only due to fusion and chemical change but also to the loss of shape in the mantle
for when the mantle was placed upon another burner and the flame so arranged
that those parts of the mantle which had become previously distorted in the flame
during the 600 hours of burning were impinged upon by the flame the illuminat-
ing power at once rose from 38 to 54 candle power. It has been found that not
only is the shape of the mantle more stable but that fusion and chemical change
in the mantle are minimised by the use of the substances and by the employment
in the production of the mantles of the process hereafter described.
Of
In carrying the invention into effect a mixture of salts of tin is made with
thorium nitrate with which is added a small percentage of the rare earths or
uranium and platinum and which contains at the same time at least 2 per cent. of
a potassium compound and is found to produce incandescent material of high
illuminating power which while keeping its shape is so strong even after once
glowing that it can be subjected to shock without being damaged. It has been
found that a high percentage of tin diminishes its quality and if the percentage
amounts to more than 20 of the total weight the mantle becomes unfit for use.
the substances specified a compound of potassium is preferably employed on
account of its cheapness. Very hard incandescent material may be made from
solutions of for example 1 to 2 per cent. of cerium nitrate or of any one or more
of other rare earths and also in other proportions or less percentage together
with 1 to 3 per cent. of potassium nitrate and 95 to 97% of thorium nitrate or
less of the latter if desired. The compound of potassium may be wholly or partly
replaced by a compound of sodium, lithium, caesium, or rubidium for example
instead of 100 grains of a compound of potassium the more expensive but more
successful combination of 8 grains of sodium 32 grains of lithium and 60 grains
of potassium may be employed; an excess of the potassium compound disappears
in the glowing operation the remainder enters into molecular combination.
It is often desirable that such incandescent materials shall in addition to being
hard possess elasticity, and this object may be effected by carefully adding a few
drops of diluted sulphuric acid to the above mentioned composition. The sul-

page_text: phuric acid should not be concentrated as precipitation would take place by its
employment.
The production of such incandescent materials can be effected in the usual
manner hitherto employed by dissolving the whole or the greater part of the
necessary substances and impregnating the mantle fabric therewith, then, after
drying, incinerating, and then imparting the desired shape to the mantle in the
fire or in hot air."
Or if operating according to Chardonnet's method the substances may be asso-
ciated with a readily combustible binding agent as for example a solution of
collodion in addition to rare earths and worked up into threads. If this method
is employed there is no restriction to use wholly or partly soluble salts as oxid
hydrates or other combinations of the elements may also be associated with the
binding agent.
In carrying the process for the production of mantles into effect according to
the present invention two separate operations are involved, the completely shaped
- incinerated incandescent material consisting almost solely of oxides being impreg
nated a second time with other substances which are intended to effect primarily
a molecular combination or union of the two impregnations. The surface of the
skeleton of the mantle on the second impregnation receives outwardly greater
masses than does the core of the mantle fabric especially when a very viscous
liquid is employed as the second impregnating agent. In the latter case little or
nothing of the salts of the second solution will reach the core of the mantle. It
is found that by the production of a mantle in this way that fusion and formation
of chemical combinations in the flame is minimised.
In carrying the process into effect according to one modification 97% parts of
thorium nitrate are dissolved with 2% parts of potassium-nitrate. With this
solution the fabric which is to be impregnated is saturated then dried incinerated
and shaped in the fire. This incandescent material is very hard. It is then
dipped quickly into a solution of cerium nitrate and can be used after being dried.
Instead of an aqueous solution it is preferable to employ a solution of chouc
gutta-percha and wax, the caoutchouc, as also the gutta-percha, are easily soluble
in chioroform, ether, and benzol but the solvents may be varied according to the
origin of the substances to be dissolved; gutta-percha rarely occurs in commerce
in a utilizable form so that it must be first dissolved in turpentine oil precipitated
with alcohol and again dissolved in chloroform. A great quantity of caoutchouc
contracts the incandescent material and makes it temporarily harder while wax
and gutta-percha have a favourable effect upon its suppleness. Into the solution
so formed a percentage of cerium nitrate is added, the cerium nitrate being first
mixed with alcohol. If the mantle be dipped into a solution of this kind the
cerium nitrate will become deposited on the surface of the threads of the mantle
fabric and the volatile substances will rapidly evaporate. Mantles of this kind
on being dried are ready for use.
It is obvious that other mixtures may be employed for the skeleton of the
fabric of the mantle, for example 10 parts of tin chlorate, 87% parts of thorium
· nitrate, with 2½ parts of potassium nitrate; while the second impregnation with
cerium can be wholly or partly replaced by other rare earths or uranium and
platinum. In this connection it may be stated that I have found that the simul-
taneous use of cerium and didymium in the process produces a beneficial effect
contrary to the general view.
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. The production and use of incandescent mantles containing compounds of
potassium sodium lithium rubidium caesium or tin or of any number of such com-
pounds in combination with one or more of the rare earths or with platinum and
uranium substantially as described.

page_text: 2. A process for production of incandescent mantles by second impregnation
substantially as and for the purpose herein before described.
3. The production and use of incandescent mantles according to Chardonnet's
method in which acid basic or neutral compounds of potassium sodium lithium
rubidium caesium or tin or any combination thereof are employed by association
with a binding agent such as a solution of collodion in addition to the rare earths
substantially as described.
4. The production and use of an incandescent mantle impregnated in a solu-
tion of thorium nitrate in a quantity less than 97 per cent. and small quantities
of any of the rare earths in combination with any one or more of compounds of
potassium, sodium, lithium, rubidium, caesium, and tin substantially as and for
the purpose as hereinbefore described.
5. An incandescent mantle substantially as herein before described.
6. A process for the production of an incandescent mantle substantially as
hereinbefore described.
ed this 3rd day of August 1996.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.