Mantles for Lighting by Incandescence, and Process of Making the same.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Mantles for Lighting by Incandescence, and Process of Making
the same.
I, ACHILLE MARIE PLAISSETTY, of 9, Rue Laffite, Paris, France, Chemist, do
hereby declare the nature of this invention to be as follows:-
This invention relates to the manufacture of mantles for incandescent lighting
by gas, mineral oil, or alcohol, and has for object to give them a degree of tenacity,
a durability, and flexibility heretofore unattainable.
The invention is based essentially on the combination obtained by the solution
of trinitro-cellulose, of cotton, wood, paper, straw, etc., in glacial acetic acid, mixed
with incandescent salts obtained from monazite sands known as rare earths, alone
or mixed with other incandescent salts, and in the treatment of the product thus
obtained with certain reagents whereby there is imparted to it the appearance of
a natural filament whilst retaining the incandescent properties of such filament.
The process of manufacture includes the preparation of the trinitro-cellulose and
its admixture with the other constituents; and the subsequent treatment of the
compound so as to bring it to the form of an incandescent filament. The
advantages of this method of manufacture are:-
1. The impregnation of the mantle is avoided;
2. The filament is continuous solid and homogeneous and the salts are uniformly
distributed through its mass.
METHOD OF OPERATION.
Nitro-cellulose is dissolved in glacial acetic acid or in ether and alcohol, the
proportions of which are not here indicated as they depend on the required vis-
cosity of the mass according as the collodion is to be spun by extrusion into a
water bath or as the pressure available is sufficient to admit of a thick and viscous
collodion being spun without the use of any bath so that coagulation will be pro-
duced by the mere passage through the air, the latter method being preferable
as the filament not being brought into contact with any liquid during coagulation
the contained salts are not liable to be dissolved out and lost.
Having thus obtained a viscous syrup of collodion I dissolve in proper propor-
tions (taking the weight of the nitro-cellulose as a basis) the incandescent salts
in the form of nitrates in a small quantity of glacial acetic acid which I mix with
the collodion as soon as the solution of the salts is homogeneous.
It is essential to mix the solution of incandescent salts with the viscous mass
before the acetic acid contained in the capsule evaporates or loses its strength by
contact with the air, in order to prevent the coagulation of the collodion at the
moment of admixture of the solution of illuminating materials, with the viscous
mass. The illuminating salts may also be dissolved in distilled water instead of
glacial acetic acid so as to enable a concentrated solution of very syrupy con-
sistency to be obtained which is to be added to the trinitro-cellulose previously
dissolved in glacial acetic acid.
The incandescent salts not being soluble in ether and alcohol require to be

page_text: dissolved in glacial acetic acid before mixture with the nitro-cellulose dissolved in
ether and alcohol, in order to obtain an intimate and homogeneous mixture.
Having thus obtained an intimate mixture of the viscous mass, the sirupy liquid
is subjected to two consecutive filtrations, first through a coarsely-meshed and
afterwards through a finely-meshed fabric. In order to accelerate and facilitate
the filtration I may employ the action of a vacuum or of pressure.
Experience has shewn that it is preferable to filter the collodion after the addi-
tion of the salts in order to obtain a completely homogeneous mixture.
The viscous or semi-fluid product is the basis of the incandescent filament which
is produced by the extrusion of the viscous mass by pressure through glass tubes,
the filament so formed being received in a bath of ammoniacal alum to remove the
excess of acetic acid. The alum bath may however be dispensed with if the extru-
sion of the viscous mass through the tubes is effected under a pressure of from 35
to 45 kilogrammes per centimetre carré (500 to 650 lbs. per square inch).
I now proceed to the operation of drying.
The thread or filament is wound on a revolving drum mounted on a sliding
carriage actuated by a worm so that the traversing motion of the carriage will
produce the spiral winding of the thread on the drum. It is then let dry and
wound on bobbins instead of being obtained in skeins. For this purpose the
reels are mounted on a support carried by the winding machine and is maintained
between two spring-pressed bearings. Rotary motion is transmitted to the reel
by pulleys which are driven from other pulleys keyed on a driving shaft. This
machine admits of doubling and twisting several threads together but it must be
provided with means of regulating the torsion which varies in practice with the
nature of the thread, or the purpose for which it is to be used. Thus, for knitting
incandescent gas mantles I employ four or five threads twisted together for the
ordinary Bunsen burner and eight to ten threads for high pressure lamps. The
meshes of the mantle may be tightly or loosely knitted according to the kind of
burner or lamp to which it is to be applied, special kinds of knitting machines
being used.
DENITRIFICATION.
The denitrification of the filament or thread thus produced is effected by passing
it through a bath of 20% to 25% pure sulphydrate of ammonia (ammonium hydro-
sulphide) heated to a temperature of 40° C. In an hour or two a completely
denitrified filament is obtained which is air-dried and which is immediately after-
wards subjected to the action of the flame.
There are other processes of denitrification as by ammonium nitrate, sulphuretted
hydrogen, alkaline solutions, hydrosulphite of zinc, etc., but they are slow in opera-
tion and the incandescent salts incorporated with the filament become to a great
extent removed by the action of the bath, whereas sulphydrate of ammonia besides
rapidly denitrifying the thread thus treated has the effect of animalizing the
substance, the weight volume and illuminating power of the conjoined salts being
retained in the collodion.
In order to increase the elasticity and tenacity of the filament I immerse it for
several days in a bath of spirit of petroleum or other mineral oil capable of
vapourizing without leaving any residuum, such as alcohol benzene, either of
petroleum, or of any other mineral or vegetable essence. This bath imparts to the
thread or filament great tenacity and elasticity and facilitates combustion which
once begun continues of itself; the thread knitted in the form of a mantle retain-
ing the form which has been given to it. The bath also serves to agglomerate the
threads and prevent them breaking during calcination. The spirit of petroleum
forming no compounds can leave no residuum in the mantle.
The advantages of the mantle made as above described over those now in use,
are that it is stronger, has a life of from 4000 to 5000 hours, and by reason of the
intimate union of the collodion with the incandescent salts it does not lose its
illuminating power as in the case of impregnated mantles which lose their illumin-
ating power in proportion to the time they are burned.

page_text: pipe flame preferably by directing the flame against the mantle
suspended upon a suitable support, whereby the contraction of the mantle to its
final form is brought about. Or the mantle may be placed on a mandrel and the
blowpipe flame directed against it in the ordinary way.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. The herein described method of producing filaments or threads for the manu-
facture of mantles for incandescent lighting, which consists in dissolving nitro-
cellulose in glacial acetic acid, mixing therewith a syrupy solution of incandescent
salts, filtering, "spinning" the mixture into the form of hair-like filaments by
extrusion through capillary dies, doubling and twisting several such filaments
together to form threads, and denitrifying the filaments or threads substantially
as herein specified.
2. In the herein described method of producing filaments or threads for the
manufacture of incandescent mantles, the employment of glacial acetic acid as the
solvent for nitro-cellulose to form a collodion capable of dissolving, or of holding
in solution, the incandescent salts or compounds.
3. The manufacture of filaments for making incandescent mantles, of a solution
of trinitro-cellulose in glacial acetic acid in combination with a solution of incan-
descent salts or compounds as described.
4. The manufacture of filaments for making incandescent mantles by combining
a solution of trinitro-cellulose in glacial acetic acid with a solution of incandes-
cent salts, filtering with the aid of a vacuum or pressure, and forming into threads
by extrusion through capillary orifices substantially as specified.
5. The production of threads for the manufacture of incandescent mantles by
doubling and twisting together a number of fine filaments produced by extrusion
through capillary dies, of collodion containing incandescent salts in solution as
described.
จ
1000
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.

page_text: OCITUTIL
10
But I may also use mixtures of zirconium and lanthanum in the proportion of
about 60% of zirconium and 40% of lanthanum with 12% of cerium, and
similarly for other salts obtained from the treatment of monazite sands.
66
All the salts above referred to are soluble in glacial acetic acid and by the sub-
sequent denitrification of the filaments the nitrates are converted into oxides.
Having obtained an intimately mixed and viscous mass it is subjected to two
consecutive filtrations, first through a coarsely-meshed and afterwards through a
finely-meshed fabric, and in order to accelerate the filtration I may employ the
action of a vacuum or of pressure, the filtration of the collodion after the addition
of the salts conducing to the obtainment of a completely homogeneous mixture.
The viscous or semi-fluid product thus obtained is then "squirted" or spun'
into the form of fine filaments by extrusion under a pressure of 5 to 10 kilo-
grammes per centimetre carré (70 lbs. to 150 lbs. per square inch or upwards)
through dies formed of glass tubes of capillary bore, the hair-like filaments so
fórmed being received in a bath of ammoniacal alum to remove the excess of acetic
acid. The alum bath may, however, be dispensed with if the viscosity of the mass
is such that coagulation ensues upon the mere passage of the filaments through
the air in which case a pressure of from 35 to 45 kilogrammes per centimeter carré
(500 to 650 lbs. per square inch) is required to effect the extrusion of the viscous
mass through the tubes.
The filaments are then wound spirally on a revolving drum mounted on a sliding
carriage receiving traversing motion by worm gear, and may at once be denitrified
as hereafter described, or may first be dried and wound on to bobbins which are
then placed in a doubling machine whereby to effect the doubling and twisting of
several such filaments together to form a thread, the degree of torsion which is
slight being varied in practice according to the purpose for which the mantle is
to be used. Thus four or more filaments are doubled to form a thread to be used
for knitting mantles to be employed with the ordinary Bunsen burner, and eight
or more filaments in the case of high pressure lamps. By combining a number
of fine lightly-twisted filaments together to form a thread as described, a greater sur-
face of contact with the flame and consequently a greater light-emitting surface is
obtained than would otherwise be obtainable and as the filaments, although
lightly twisted together, are still separate and distinct their aggregate incandes-
cence is greater than would be that of a single filament of the same size as the
combined filamentary thread.
The denitrification of the filaments or of the doubled and twisted threads (as the
case may be) is effected preferably by immersion in a bath of 20% to 25% sulphy-
drate of calcium (calcium hydrosulphide) heated to a temperature of 40° C., the use
of calcium hydrosulphide for this purpose forming the subject of another applica-
tion for Letters Patent dated the 15th day of February 1898, No. 3770. In an
hour or two the thread is completely denitrified and the salts are precipitated in
the filaments in the form of oxides.
The thread is then air dried and the mantle is formed by knitting in the ordinary
way, the meshes of the mantle being tightly or loosely knitted according to the
kind of burner or lamp to which it is to be applied.
The mantle after being knitted is subjected to the action of a blow-

page_text: The mantle being formed of a solid thread or filament can withstand shocks and
even if partially fractured does not break up under the action of heat as is the
case with mantles which being produced by impregnation are formed of hollow.
threads having scarcely any strength whatever.
Dated this 12th day of November 1897.
A. M. & WM. CLARK,
Chartered Patent Agents,
53, Chancery Lane, London.
Mantles for Lighting by Incandescence, and Process of Making
the same.
I, ACHILLE MARIE PLAISSETTY, of 9, Rue Laffite, 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 the manufacture of mantles for incandescent lighting
and has for its object to produce mantles possessing a degree of tenacity, flexibility,
and durability both of structure and of illuminating capacity unattainable by the
method of impregnation heretofore generally employed,
The invention consists essentially in the preparation of a collodion capable of
holding in solution, or of forming an emulsion with, salts or compounds sus-
ceptible of yielding a residue having the property of emitting light by
incandescence. A collodion giving good results is formed by the solution of
trinitro-cellulose in glacial acetic acid, and the invention comprises the preparation
of such a collodion holding in solution or emulsion the incandescent salts or com-
pounds the production therefrom of filaments by extrusion through capillary dies,
the doubling together of such filaments to form loosely twisted threads, and deni-
trification of the filaments or threads as hereafter described.
Filaments produced as herein described are homogeneous in that the salts are
uniformly distributed throughout their mass and being of compact solid structure
possess relatively great strength as compared with the extremely fragile porous
or hollow filaments produced by impregnating threads of organic material with:
the incandescent salts and then burning out the organic matter.
"
The method of operation is as follows:-Nitro-cellulose is dissolved in glacial
acetic acid, in proportions which depend on the degree of viscosity required which
may vary according as the collodion when "
spun' or formed into filaments by
extrusion is to be passed through a coagulating bath, or as the pressure available
is sufficient to thus "spin' a collodion which is so viscous that coagulation will
be produced by the mere passage through the air without the use of any bath, the
latter method being preferable.
"
I take, say, 1200 grammes of glacial acetic acid, 100 grammes of gun cotton,
and from 30 to 50 grammes of incandescent salts according to their quality and
illuminating power. I first make a sirupy or concentrated solution of the incan-
descent salts in the form of nitrates in a small quantity of glacial acetic acid.
I then dissolve 35 grammes of the gun cotton in 500 grammes of the glacial acetic
acid, and add slowly the sirupy solution of the salts thereto, stirring meanwhile
so as to produce a homogeneous mixture. I then dissolve the remainder of the
gun cotton in the remainder of the glacial acetic acid, and these two solutions are
then mixed by adding small quantities of the former successively to the mass
of the latter.