An Improved Manufacture of Mantles to be Used in Incandescent Gas Lighting.
Year: 1899

page_text: Date of Application, 8th Aug., 1899-Accepted, 17th Mar., 1900
COMPLETE SPECIFICATION.
An Improved Manufacture of Mantles to be Used in Incandescent Gas
Lighting.
A communication from FRED ISITT, of 64, Redmond Street Leichhardt, in the
Colony of New South Wales, Agent.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of London,
Chartered Patent Agent, 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:-
:-
Hitherto the structures of mantles, for incandescent gas lighting, have been
either metallic, amorphous, or porcelanous; but in practice, these structures.
for many reasons leave much to be desired.
The object of this invention is (1) the manufacture of an incandescent mantle.
whose structure shall be nearer a crystalline form. Such crystalline structure will
prove to be far stronger and tougher than the other structures above signalised.
(2) To maintain, with undiminished intensity, the incandescence of the mantle
after it has been in use for some time. (3) To reduce or to eliminate altogether.
the objectionable greenish tinge in the colour of the light, after the continuous
use of the mantle, for an extended period.
Moreover, a certain class of metals are introduced in the manufacture of the
mantle which shall have the effect of inducing a true catalytic action in the
particles of which the mantle is composed, with the result that (by varying some
of the elements introdued) a powerful light of any desired colour may be produced.
My correspondent employs as a body an oxide of an earth or earths of relatively
low light-giving capacity in itself, as, for instance, aluminate of glucinum, in
mechanical mixture with other oxygen carriers and semi metals, such as anti-
mony, and with a very small proportion of a metal of the platinum group, which
latter should be present in such infinitesimal quantity, and so distributed through
the mass, that its presence will be discoverable only by its oxygenising action,
and which action, in the absence of such platinous metal, would not be produced.
The oxide of an earth or earths as a body may be used without admixture
with other oxygen carriers and semi metals, but must always be in combination
with a very small quantity of a platinous metal.
It has been shown in Williams' Patent (N.S. Wales No. 1829) that if lanthanum
and yttrium be added to zirconium in the following proportion, a large almost
white light will be produced. 60 per cent. of zirconia, 20 per cent. lanthaunm,
and 20 per cent. yttrium, or the oxide of yttrium, may be dispensed with, the
composition being then 50 per cent. zirconia and 50 per cent. lanthanum.
Carl Delwik in his English Patent, No. 2110 of 1890, maintains that a powerful
red light may be produced from a base of zirconium, to which a small proportion
of chromium is added.
It is also described by Auer von Welsbach in his Patent (N.S. Wales No. 4958
of 1894) that thorium in a pure state gives comparatively little light, but when it
has added to it a small proportion of the oxides of certain rare metals, such as

page_text: cerium, terbium, neodymium, samarium, praseodymium, yttrium, and lanthanum,
it has a high illuminating power. It has farther been shown that the oxide of
cerium was found to act upon and to excite the thorium, resulting in a marked
increase in illuminating power.
It has, moreover, been asserted that various other combinations, or ingredients,
pcssessing similar exciting properties, may be used for a like purpose. In such
cases thorium or zirconium oxides have been generally proposed as being most
suitable to form the main body or mechanical base, with a small quantity of
the oxide of one or more rare earths, mechanically combined therewith. Although
such oxides of rare earths may, in some cases, be of service, they are rather
theoretically than practically useful as exciting media, when considered from
the commercial point of view.
My correspondent has discovered, after a thorough practial investigation of the
subject, that, in the total absence of cerium oxide, none of the earths mentioned
have the power of appreciably increasing the light from a mantle composed
mainly of thorium oxide or of the oxides of other earths. Wherever such increased
illumination has resulted, it has been due to the presence of, at least, a trace of
cerium oxide, an exceedingly small quantity of which will give wonderfully
improved results. Oxide of cerium is the only one of the cerite and yttrite groups
of earths, which is for this purpose of practical commercial value.
<<
"
*
He has further discovered that the oxides having the above-mentioned properties
may be divided roughly into two classes, which he designates as carriers" and
as developers." Carriers are oxides of high melting point, and are stable,
such as aluminium, glueinum, zirconium, calcium, magnesium, and thorium.
They are called "carriers" because they form a large proportion of the whole,
and thus serve as bases or carriers for the light-developers, which are in much
smaller relative proportions. Indium and gallium are peculiar, inasmuch as they
may be used to an appreciable extent both as carriers and as semi-developers.
There are a number of other elements which partly possess this property, and
others again which only possess it, to some extent. in the presence of related
oxides.
39
"Developers of light and colour (often called semi-developers) are variable
oxides according to their degrees of volatility such as cerium, manganese, indium.
gallium, chrome, and such like On these will depend the light, the colour, and
the relative permanence of the incandescent life of the mantle."
The oxides of glucinum, aluminium, zirconium, thorium, magnesium, calcium,
and such like elements, and the various mixtures and compounds thereof, are of
no considerable value in themselves for the production of mantles for incandescent
lighting, but the addition of a small proportion of vari-colour semi-accelerators or
developers in combination with a very small proprtion of a true exciter or
developer," consisting of some metal of the platinum groun, will give a powerful
incandescent light, which may be varied in colour, according to formulæ, from
red to almost white.
"
The true "developer," which should be platinum. iridium or other suitable
metal of the platinum group, is introduced in order that a true catalytic action
may be set up and this constitutes one of the main features of this invention.
The catalytic action is due to the fact that a platinous metal has a great mechanical
affinity for 'oxygen, possessing the faculty of attracting that gas from the
atmosphere, and maintaining it in large quantities on its surface. It was shown
by Döbreiner in 1825 that platinum has the power of holding one hundred volumes
of oxygen. The platinum, though incapable of chemically combining with
oxygen, will collect and maintain a large supply of that gas over the surface of
the mantle, and the oxygen, combining with the gas from the burner (as supplied
constantly to the flame on the inner side of the mantle), will induce or cause
a more perfect combustion of the hydro-carbon gas. To all appearance. this
action is continuous, but, as a matter of fact. it is really alternate or intermittent.
as may be seen by the result. The greater heat which is due to the presence of

page_text: 15
additional oxygen causes the incandescence of the mantle, which serves as a
radiating, diffusing or distributing body for throwing off the light thus developed.
The precise mode of making the mantle is not of great importance, but, in
practice, it is preferred to employ a basis or scaffolding" of stockinette or
other suitable thoroughly clean filamentary fabric. This fabric must be impreg-
nated with a solution consisting of soluble salts of aluminium in the proportion
of from 20. per cent. to 40 per cent., together with soluble salts of glucinum in
the proportion of from 20 per cent. to 40 per cent., dissolved in water, and with or
without oxides of incandescent earths of relatively low light giving capacity in
themselves. The proportion of the combined salts of aluminium and glucinum
may thus vary from 40 per cent. to 80 per cent. of the whole.
Instead of dipping the filamentary fabric into the solution of the combined salts
of aluminium and glucinum, mixed with the oxides of incandescent earths, it may
be first dipped into a solution consisting only of the salts of aluminium and
glucinum, then dried, and afterwards dipped in or sprayed with a solution of
the oxides of incandescent earths. In any case, the mantles thus far prepared
will consist only of "carriers."
It may be advisable to further treat the base or body thus formed, impregnated
and dried, by dipping it into an alkali-fixing solution, preferably aqua-ammonia,
or by introducing it into an atmosphere of ammonium hydrate, whereby the salts
of the metals will be decomposed, and a coating formed of hydrated oxides, and
the corresponding salts of ammonia. It should then be partly dried again,
and the salts of ammonia washed out by means of distilled water, in order. to
prevent injurious re-actions in the framework. This operation. is important 'in
cases where the impregnated fabric is to be put in stock or transported.
The mantle after having been dried and shaped, will be burnt out over a gas
flame. in the usual manner, and thus the scaffolding". (consisting of the
stockinette or other filamentary fabric) will be destroyed, while the oxides or body
ofcarriers" constituting the frame work will be left in the form of a mantle.
The oxides of the minerals are now in the proportion in which the chemical
compound consisting of glucinum aluminate is formed. This compound frame-
work or base, although artificially produced, will possess. great infusibility and
unalterability, and will be quite stable.
The framework or carrier will then be dipped into or sprayed with. a
solution of a "developer" composed of one or more of the catatlytic incandescing
bodies which will be hereinafter referred to.. When the mantle has been treated
with the required "developer" it may be advisable to again. subject the formed
mantle to the action of ammonia gas. as before explained, in order that the
developer salts may be decomposed and then, in order to fully and properly unite
the "developers" with the "carriers," and to ash the chlorides of platinum or
iridium (which in the meantime have been transformed to their hydro oxides),
it will be necessary to again burn out the mantle. the, result of which will be to
leave an ash of the oxides or developers "with a very minute proportion of
platinous metal so distributed over or throughout the mass as to produce the
desired catalytic action.
"
If it be more convenient or desirable. the "carrier" and "developer" elements
may be combined in one solution, applied to the filamentary fabric or "scaffolding"
in one dipping, and the whole burnt out together at one time.
Although the mantle constructed, as above described, would be strong enough
to stand the necessary rough handling involved in transit, yet it may be advisable,
under certain circumstances, to cover the mantle with a protective coating which
will act as a temporary "binder" or strengthener. Such a "binder" may consist
of a solution of collodion. pyroxylin, dissolved gun-cotton, or some suitable
nitro-cellulose compound. The binder" may be utilised as a vehicle to carry
the "developer or exciting medium. When this is the case, the mantle will
be placed in its permanent position on the usual gas burner, the "binder"
composition will be consumed and destroyed, while the "developer
" or exciter
will remain evenly distributed over the surface of the mantle, and thus will
.

page_text: 32
not be covered by the oxide or main body of the mantle, but will be exposed
just where it is most required. It must be understood that if the "developer
be applied to the mantle through the medium of the binder" composition, it
must be left out of the "carrier" solution, and, indeed, must not be applied in
any other way; otherwise, there will be a too large proportion of "developer,"
and the special object for which it is introduced would be defeated.
It will be remarked that the fundamental principle involved in this invention
is that the mantle shall be composed of a stable base called the
66 carrier," and
an exciting medium called the "developer," which must contain a minute or
invisible quantity of some metal of the platinum group, whereby a true catalytic
action is set up.
The platinous metal or metals which are utilized to produce the catalytic
action should be applied in the form of chlorides, and when the mantle is burnt
out, these metals will exist neither as salts nor as oxides, but as chlorides trans-
formed to metallic platinum or iridium and distributed in minute and invisible
quantity throughout or over the surface of the oxygen "carriers."
66
The proportions of the ingredients used, and the selection of ingredients
themselves, which constitute the <<
carriers," the semi-developers," the colour
producing oxygen carriers," and the catalytic excitant or developer" will
be varied, according to the illuminating power required, the colour of the light,
and the desired stability of the mantle.
The following schedule will give a fair idea of the combinations of minerals
which may be used as developers:
<<
1. For a white light:-a solution of soluble salts of aluminium or other
stable "carrier." indium or gallium, with a trace of chloride of iridium.
2. For a yellowish white light:-
:-a solution of soluble salts of aluminium or
other stable "carrier," gallium, or indium, calcium and a trace of platinum
chloride.
3 For a ruddy or pinkish white light:-aluminium or other stable "carrier,"
gallium, pent-oxide of vanadium, iridium chloride, platinum chloride.
4. For a ruddy white light: -aluminium or other stable
cobalt, tungsten. platinum chloride.
carrier," calcium,
5. For a reddish yellow light:-aluminium or other stable "carrier," indium,
chromium barium, and platinum chloride.
By varying the proportions, almost any shade of colour from almost white
to a yellowish red may be produced.
The following will serve to illustrate a "carrier" solution:
Soluble salts of aluminium, or other stable "carrier,"
Soluble salts of glucinum
-
-
49*98
49°98
To which may be added one or more of the following ingredients, which will
act as strengtheners: -calcium or magnesium, from 1 to 04 part, pyrotartaric
acid, 1 part, chloride of antimony, 5 part; water to be added until the desired
strength is obtained.
+6
"
It will be understood that to 99'96 parts of the "carrier" must be added a
trace of a metal of the platinum group, in the proportion of from 03 to 06 part.
It is optional whether the carrier" and developer elements be applied
in one or in 'wo operations; but for mantles which are intended to be used
for high pressure gas lighting it is preferred to form the skeleton, or framework
(i.e.. carriers") of such a solution as that above indicated, and then, subsequently
apply the "developer element consisting of about 04 part of a platinous metal;
but the proportions must always be approximately 99'96 parts of "carriers
04 parts of "developers."
to
For mantles that are intended to be used at ordinary pressures, the platinous
metal or developer" may be added to the "carrier" solution (which in that
case should preferably consist of but one staple as base), and but one dipping
would be sufficient. Such a mantle would emit a very powerful light, and would
be sufficiently strong for ordinary pressures.

page_text: The above formula is given merely as an illustration of the manner in which
my invention may be given practical effect, but my correspondent does not wish
to bind himself down to use any special formula, as the formule may be so largely
varied without departing from the spirit of my invention, which consists of a
large proportion of a stable carrier," such as soluble salts of aluminium, of
semi-developers," such as indium or gallium, in far smaller proportions, and
in a metal or metals of the platinous group, such as chlorides of platinum or
iridum in infinitesimal proportions, in order to cause a catalytic action.
It is important to remark that the proportions of the platinous metal, which
produces the true catalytic action, must be strictly confined within certain
limits. Such proportions should not be less than 0.03% nor more than 0.07%.
If these limits be exceeded or passed, the benefit, due to the presence of the
plutinous metal, will be neutralised and the issue defective. My correspondent
has discovered that a proportion of from 0'04 to 0.05% gives the most satisfactory
results.
Having now particularly described and ascertained the nature of the said
invention, as communicated to me by my foreign correspondent, and in what
manner the same is to be performed, I declare that what I claini is :-
1. A base or "carrier" for incandescent mantles, consisting of glucinum
aluminate, in combination with an infinitesimal proportion of a metal of the
platinum group, as herein set forth.
"
2 A base or
"
carrier for incandescent mantles, composed of glucinum
aluminate, or other stable earth or earths of high melting point, in a large
proportion, mixed with a much smaller proportion of an oxide or oxides of
the incandescent earths, all in combination with an infinitesimal proportion of a
metal of the platinum group, as and for the purposes specified.
وو
3 Developers" that are applied to the " carriers in incandescent mantles,
such developers" being composed of a mixture of oxides, in which the oxides
of indium or gallium are mixed with the oxides or metals of the incandescing
earths, approximately in the proportions specified, in combination with a trace of
a metal of the platinum group, which causes a catalytic action to he set up, as
herein set forth.
4. A mantle for incandescent gas lighting consisting of glueinum aluminate
with or without calcium and magnesium oxide or other carriers" in which the
oxides of gallium or indium are contained, singly or in combination with
other oxygen "carriers or developers," and with a metal of the platinum
group distributed in minute and invisible proportions over the surface of the
oxides, whereby a catalytic action is set up, as specified..
5. A mantle for incandescent lighting consisting of a body of incandescing
earth or earths, metal or metals of relatively low light giving capacity, combined
with such minerals as indium, gallium, vanadium; as semi-developers, and a
metal of the platinum group in exceedingly minute proportions, whereby a
catalytic action is secured, as herein specified and for the purposes set forth.
6. In combination, an incandescent earth or earths, metal or metals, of relatively
low light-giving capacity in itself or themselves, and high melting point, approxi-
mately in the proportions specified, as a base, and a metal or metals of the
platinum group, in infinitesimal proportion distributed over the base as a deve-
loper," thereby causing a true catalytic action as herein specified and for the
purposes set forth.
D
"