Improvements in or relating to the Manufacture of Mantles for Incandescent Gas and other Lighting.
Year: 1898

page_text: Date of Application, 15th Feb., 1898
Complete Specification Left, 14th July, 1393 -Accepted, 15th Feb.,
1899
Improvements in or relating to the Manufacture of Mantles for
Incandescent Gas and other Lighting.
I, ACHILLE MARIE PLAISSETTY, of 9, Rue Laffitte, Paris, France, Chemist, 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 the manufacture of mantles for
lighting by incandescence and consists essentially in the manufacture of a filament
from a solution of tri-nitro-cellulose (of cotton, wood, paper, straw or other suitable
material) in glacial acetic acid with the addition of salts capable of producing
light by incandescence.
The process of manufacture comprises the preparation of the tri-nitro-cellulose
and its admixture with the other constituents and also the subsequent treatment
of the composition in order to bring it to a thread-like form capable of being
knitted or otherwise woven into the form of a mantle.
By the process of this invention a homogeneous solid and continuous filament
is obtained in the mass of which the oxides or salts are uniformly distributed;
the process of steeping or impregnating the mantle is obviated, and the mantle
made with the solid filament produced according to this invention is much stronger
than those produced in the ordinary way which by reason of the hollow form of the
filaments are very fragile.
The method of producing the filament is as follows:-I take glacial acetic acid
1200 parts by weight; gun cotton 100 parts; incandescent salts 30 to 50 parts,
according to their quality and illuminating power.
I first make a 100 % solution of the last mentioned in water or glacial acetic acid
and concentrate to a syrupy consistency. I then dissolve 35 parts of gun cotton
in 500 parts of glacial acetic acid (part of the above quantity) and then add the
previously prepared syrup of salts to this solution, agitating meanwhile so as to
obtain a homogeneous mixture. I then dissolve the remaining 65 parts of gun
cotton in the remaining 700 parts of glacial acetic acid. These two solutions are
then mixed together by adding the first mentioned in small quantities successively
to the last mentioned. This operation having been completed an intimate mixture
is obtained in the form of a viscous mass which is twice strained, first through a
coarse and secondly through a fine meshed fabric, the filtration being hastened if
necessary by the aid of a vacuum or of pressure.
The viscous mass thus produced is converted into the form of a filament by
extrusion through a capillary tube the resulting thread or filament being dried
after winding on a drum mounted on a carriage actuated by a worm in such manner
that he traversing motion of the carriage produces the helical winding of the
thread on the drum.

page_text: The thread or filament after being dried is wound on bobbins which are mounted
in a doubling machine or mill whereby a number of filaments are combined, the
machine being provided with means of varying the degree of torsion which depends
on the nature of the thread or the purpose for which it is to be applied, the number
of threads combined together being greater or less according to the burner on
which the mantle is to be used.
The denitrification of the filament is effected by means of calcium hydro-sulphate
followed by a washing in an ammonical bath to remove the excess of lime absorbed
by the filament during de-nitrification.
I have however succeeded on burning off, in neutralizing the inflammability of
the non-denitrified filament by immersion for a few (four or five) days in a bath
of spirit of petroleum or other oil of the same category capable of being vapourized.
This bath imparts to the filament great elasticity and tenacity whilst favouring
combustion, and the combustion once started continues uninterruptedly, and the
filament knitted in the form of a mantle retains the form given to it. It also has
for effect to agglomerate the filaments and prevents them becoming broken by
calcination, whilst the petroleum spirit forming no compound leaves no residue in
the mantle.
The mantle made of this filament is of special form such that the light rays
are emitted in a more useful direction than from ordinary mantles whence a great
increase of the effective illuminating power. This form is represented in the
accompanying drawing from which it will be seen that the mantle is bulbous or
approximately the form of an inverted tulip so as to present a light emission surface
which is as nearly as possible horizontal as distinguished from the almost wholly
vertical surface of ordinary mantles.
The mantle manufactured as herein described is much stronger and much more
durable than those now in use and in consequence of the intimate mixture of the
collodion with the salts it does not rapidly lose its illuminating power as do mantles
which are treated by impregnation. The mantle being stronger is better able to
resist rough usage and even when partially fractured or slit does not become
disintegrated by the heat of the Bunsen burner.
Dated this 15th day of kahruary 1000
Improvements in or relating to the Manufacture of Mantles for
Incandescent Gas and other Lighting."
I, ACHILLE MARIE PLAISSETTY, of 9, Rue Laffitte, Paris, France, Chemist, 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:-
i
This invention relates to the manufacture of mantles for lighting by incan-
descence, and consists essentially of an improvement in the process of producing
filaments from a solution of trinitro-cellulose in glacial acetic acid or acetone with
the addition of salts capable of producing light by incandescence, which process
forms the subject matter of a previous application for Letters Patent dated the 12th
day of November 1897 No. 26,381.
The process of manufacture therein described comprises the preparation of the

page_text: collodion holding incandescent salts in solution or emulsion, the production of
filaments, and the doubling and twisting the filaments into threads capable of being
knitted into the form of a mantle, the method of producing the filaments being as
follows: I take glacial acetic acid or acetone 1200 parts by weight, gun cotton
100 parts, incandescent salts 30 to 50 parts according to their quality and illumin-
ating power.
I first make a syrupy solution of the salts in glacial acetic acid or in acetone,
or it may be a concentrated aqueous solution. 1 then dissolve 35 parts of gun
cotton in 500 parts of glacial acetic acid or in acetone (part of the above quantity)
and then add the previously prepared syrupy solution of the salts to this solution,
agitating meanwhile so as to obtain a homogeneous mixture. I then dissolve the
remaining 65 parts of gun cotton in the remaining 700 parts of glacial acetic acid
or acetone. These two solutions are then mixed together by adding the first
mentioned in small quantities successively to the last mentioned. This operation
having been completed, an intimate mixture is obtained in the form of a viscous
mass which is twice strained, first through a coarse and secondly through a fine
fabric, the filtration being hastened, if necessary, by the aid of a vacuum or of
pressure.
6:
""
17
The viscous mass thus produced is spun or squirted" into the form of
filaments by extrusion under high pressure through capillary tubes, the resulting
filaments being each wound on a drum mounted on a carriage receiving a traversing
motion by suitable means so as to wind the filament spirally on the drum.
The filaments may at once be denitrified as hereafter described or after being
dried may be wound on bobbins which are mounted in a doubling machine whereby
a number of filaments are combined in the form of a lightly-twisted thread, means
being provided of varying the degree of torsion, the number of threads combined
being also varied according to the kind of burner on which the mantle is to be
used.
The denitrification of the filaments or of the doubled and twisted threads whereby
their inflammability is destroyed, is effected by immersion in a bath of sulphydrate
of calcium (calcium hydrosulphide) for half an hour (more or less according to the
degree of temperature and the strength of the liquid) care being taken to stir
continually with a rod of glass or wood so as to ensure thorough penetration of the
fibres by the reagent. A suitable strength of the calcium hydrosulphide bath for
denitrification is 42 when titrated with iodine liquor. The threads are then sub-
jected to several repeated washings in water and may even be kept for a long
period in water in order to completely eliminate the lime residue which the thread
may contain. This capability of the threads to withstand as much washing in
water as may be necessary without danger of dissolving out the illuminating
material is due to the fact that the latter is insoluble in water, since the nitrates
have been converted into anhydrous oxides by the denitrification by means of
calcium hydrosulphide. Consequently the burning-off of mantles made from such
threads has only for result the instantaneous desiccation which brings about a perfect
contraction of the oxides so that whereas impregnated mantles contract 10 % to 15%
after a few hours burning, mantles made according to this invention do not suffer
any contraction by the heat of a Bunsen burner.
The invention also comprises a special form of mantle made by knitting threads
formed as above described, the form being such that the light rays are emitted
in a more useful direction than from ordinary mantles whence a great increase
of the effective illuminating power. This form is represented in the drawing
accompanying my Provisional Specification from which it will be seen that the
mantle is bulbous or approximately spherical towards the middle of its length,
instead of being cylindrical as usual, so as to present a downwardly-directed
light-emission surface, as distinguished from the almost wholly vertical surface
of ordinary mantles. This bulbous form is imparted to the mantle partly by
shaping in the knitting and partly by the action of the blowpipe flame used to burn
off the mantle, the flame being for that purpose directed against the inside of the

page_text: suspended mantle so that the force of the flame controls the contraction of the
mantle.
Having now particularly described and ascertained the nature of the said in-
vention, and in what manner the same is to be performed I declare that what I
claim is:-
―:
1. In the manufacture of mantles for incandescent lighting from a solution of
trinitro-cellulose and of incandescent salts " 'spun" into the form of filaments,
effecting the denitrification of the filaments or threads by the action of calcium
hydrosulphide substantially as specified.
2. The manufacture of mantles for incandescent lighting, of the bulbous form
herein represented so as to obtain more effective illumination as described.
Dated this 14th day of July 1898
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.