Improved Process of Manufacturing Igniters for Gas.
Year: 1899

page_text: Date of Application, 5th Aug., 1899
Complete Specification Left, 10th Jan., 1900-Accepted, 31st Mar., 1900
Improved Process of Manufacturing Igniters for Gas.
We, LEOPOLD FRIEDEBERGER, of No. 28, Burgstrasse, Berlin, Prussia, Germany,
Merchant, and THE "VULKAN" GESELLSCHAFT FÜR SELBSTZÜNDENDE GLÜHKÖRPER
MIT BESCHRÄNKTER HAFTUNG, a company incorporated according to the laws of
Prussia, domiciled in the same place, do hereby declare the nature of this
invention to be as follows;
or
The present invention relates to the manufacture of ignition masses
igniters for gas by means of metals of the platinum group, and has for its
object to so improve the manufacturing process that long-living and reliable
igniters result.
"
"
66
The attempts hitherto made to use the catalytic force exerted by the metals
of the platinum group when in an extremely finely divided state, for lighting
gas burners, have been restricted to the employment of said metals either in
the state of " sponge or "black" applied in a coherent layer or embedded in
the pores of a refractory mineral support. These "sponge or black" igniters
do not, however, constitute a satisfactory solution of the problem, inasmuch as
they lose their catalytic capacity after a comparatively short period of exposure to
the air, moreover, the platinum sponge and black have proved to be greatly
lacking in resistance to the shocks and frictional contact of the current of gas.
The attempt to obtain igniters of longer life by calcining a mixture, pre-
pared by way of solution, of salts of refractory oxides, such as the oxides of
earth metals, for instance nitrate of thorium, with platinic chloride, that is
British Patent
to say hydrogen-platinum chloride (H2PtCl + 6H2O)-see
No. 21935/1897-must be considered as a failure, as this kind of igniters
requires to be heated before hand in order to cause ignition of the gas.
Experiments on the basis of such mixtures as cited in the second place have
led to the discovery that the ignition can be caused to take place without pre-
vious heating of the igniter, if instead of using the said platinic chloride or
hydrogen-platinum chloride alone, it is employed in combination with a platinum
cyanide. However the igniters so prepared, have proved to retain some unde-
composed chloride which, by its absorption of moisture, renders the ignition
unreliable in damp weather. By further experiment's it has been discovered
that this hygroscopicity of the igniter is entirely removed, if a refractory acid
(or a salt leaving behind such acid on calcining) be added to the mixture,
such addition having the effect of expelling the last trace of chlorine.
By properly applying the discoveries stated, an igniter is obtained which will
not only ignite the gas with certainty in any state of the weather, but which
maintains its igniting capacity for a very long time.
This result is obtainable with any metal of the platinum group or any mixture
of such metals.

page_text: The essence of the present invention accordingly consists in manufacturing
gas-igniters by calcining an intimate mixture of a salt yielding a refractory
oxide, a cyanide of a metal of the platinum group, hydrogen platinum chloride
or a corresponding chloride of another metal of the platinum group, and a
refractory acid or a salt leaving behind such acid.
Both the cyanides and the chlorides may be used either in the form of
uncompounded or compounded salts; examples of the latter are for instance:
a Cyanide of barium and platinum (BaPtCy+ + 4H2O) cyanide of magnesium
aud platinum (MgPtCy+7H2O), cyanide of ammonium and platinum ((NH4)
2PtCy+2H20), cyanide of zine, platinum and ammonium:-(ZnPtCy+2 NH3 +
H2O), cyanide of thorium and platinum (ThPt2Cys + 16H2O), and the like, or
corresponding cyanides of the other metals of the platinum group.
b: Chloride of thorium and platinum :-(PtCl + ThC12H2O), chloride of
magnesium and platinum, chloride of ammonium and platinum :-(PtCl + 2NHCI),
and the like, or corresponding chlorides of the other metals of the platinum group.
As refractory oxides, all oxides of the alkaline earth metals and the earth
metals may be used in the form of such salts as are decomposable by heat, as,
for instance, nitrate of thorium, nitrate of magnesium, nitrate of zinc, and
the like.
As refractory acids may be used: silicic and fluorhydric acid, fluosilicic acid,
boric acid, phosphoric acid, and the like, either as such or in the form of decom-
posable compounds, such as alkaline silicates, chloride of silicon, organic silicon
compounds, soluble borates, soluble phosphates, and the like.
We prefer to use as most advantageous: Platinic chloride or hydrogen-
platinum chloride (H2PtCl + 6H20; together with the double cyanide of
barium and platinum (BaPtCy4 4H2O). as the metal yielding component, and
nitrate of thorium as the refractory oxide yielding component, in combination
with silicic acid as the refractory acid component. The employment of silicic
acid has in addition to its very energetically expelling action on the chlorine,
the important technical advantage that it enables by means of the
impregnation method usual in the manufacture of incandescent mantles shaped
igniters to be manufactured in which a large surface is combined with great
resisting power to shocks and permanence of shape.
In carrying out the invention in its most perfect form known to us we
proceed as follows:
A fabric of cotton (wool, silk, asbestos or the like) is first impregnated with
a solution of water-glass (soluble silicate of potassium or sodium), and, after
cautious drying it is treated with a mineral acid, preferably hydrochloric acid,
whereby the alkaline silicate is decomposed, and its silicic acid caused to remain
behind in the gelatinous state. The first silicated fabric is impregnated with
a watery solution containing 25 parts hydrogen-platinum chloride (platinic
chloride (H2PtCl + 6H2O) 6 parts double cyanide of barium and
platinum (BaPtCy+ + 4H2O) and 19 parts of nitrate of thorium in 50 parts
water. After drying the impregnated silicified fabric is cut into pieces of
desired size and form, and then these pieces are exposed to the action of heat
so as to reduce the thorium nitrate to thoria, and the platinum salts to
platinum. Thus a withstanding refractory structure is obtained intermingled
with extremely fine particles of platinum.
The proportions for the mixture given in the above example are thus which
we prefer to use, but may be varied within wide limits.
If it is desired to use the invention for manufacturing the igniting com-
position in the condition of a formless mass this may be obtained by mixing
the aqueous solution of thorium nitrate and said platinum salts with pure
hydrated silicic acid, evaporating the mixture to dryness on the water-bath,
and calcining the residue whereby a crumbly mass is obtained.

page_text: In like manner as above we proceed with the other component substances
cited as equivalents.
Dated this 4th day of August 1899.
Improved Process of Manufacturing Igniters for Gas.
We, LEOPOLD FRIEDEBERGER, of No. 28, Burgstrasse, Berlin, Prussia, Germany,
Merchant, and THE "VULKAN" GESELLSCHAFT FÜR SELBSTZÜNDENDE GLÜHKÖRPER
MIT BESCHRÄNKTER HAFTUNG, a company incorporated according to the laws of
Prussia, domiciled in the same place, 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:-
The present invention relates to the manufacture of ignition masses or
igniters for gas by means of metals of the platinum group, and has for its
object to so improve the manufacturing process that durable and reliable
igniters result.
33
or
The attempts hitherto made to use the catalytic force exerted by the metals
of the platinum group when in an extremely finely divided state, for lighting
gas burners, have been restricted to the employment of said metals either in
the state of "sponge" or "black" applied in a coherent layer or embedded in
the pores of a refractory mineral support. These "sponge
"black" igniters
do not, however, constitute a satisfactory solution of the problem, inasmuch as
they lose their catalytic capacity after a comparatively short period of exposure to
the air, moreover, the platinum sponge and black have proved to be greatly
lacking in resistance to the shocks and frictional contact of the current of gas.
The attempt to obtain igniters of longer life by calcining a mixture, pre-
pared by way of solution, of salts of refractory oxides, such as the oxides of
earthy metals, as for instance nitrate of thorium, with platinic chloride, that
is to say hydrogen-platinum chloride (H₂PtCl + 6H20) has not resulted in
a perfect solution of the problem. Such igniters (see for instance British
Specification No. 21935 of 1897) require a body of metallic platinum, for
instance, a wire or several wires, to be located within their mass in order to
store the heat produced by the action of the sponge or black, so that a certain
duration of contact between the igniter and the gas to be ignited is necessary
to cause the former to act. Moreover, there is a great liability of the coherence
of the igniting composition to the said wire or wires becoming broken and of
the igniting mass cracking owing to the differences between the expansion and
contraction coefficients of the two substances. Moreover platinum sponge or
black prepared from platinic chloride always retains some undecomposed chloride,
which being a hygroscopic substance, renders the igniter unreliable in damp
weather.
It has been discovered that with mixtures of the last named description a
quicker igniting action can be obtained and the life of the igniter considerably
prolonged, when the platinic chloride, by which term is meant hydrogen-
platinum chloride (H,PtCl + 6H₂O) is not used alone in combination with
the earthy oxide, but is intermixed with a cyanogen compound of platinum.
Platinum cyanides, the single cyanide as well as the composite ones, besides
aiding in driving out the chlorine, as they are very energetic reducing agents,
have the property of yielding on reduction by heat, the platinum in the metallic

page_text: state and not, as the chlorides do, in the form of sponge or black. Thus when
a mixture of platinic chloride with a platinum cyanide is reduced by the action
of heat, a sponge results which is intimately intermingled with very fine
laminae of metallic platinum. When brought in contact with lighting gas
such mixture develops a very rapid incandescense, and an almost instantaneous
lighting of the gas takes place. Thus. the use of platinic chloride intermingled
with a platinum cyanide not only improves the lighting action of the resulting
igniter, but also simplifies the manufacture as it allows the embedding of special
platinum bodies in its mass to be dispensed with. Moreover, as the metallic
particles of platinum are finely distributed throughout the whole mass, the
liability to crack is greatly reduced or in other words the igniter is given an
accordingly longer life. However, the igniters so prepared, have proved to
retain some undecomposed chloride which, by its absorption of moisture, renders
the ignition unreliable in damp weather. By further experiments it has been
discovered that this hygroscopicity of the igniter is entirely removed by the
addition of a refractory acid (or a salt leaving behind such acid on calcining)
to the mixture, such addition having the effect of expelling the last trace
of chloride.
By properly applying the discoveries stated, an igniter is obtained which will
not only ignite the gas with certainty in any state of the weather, but which
maintains its igniting capacity for a very long time.
This result is obtainable with any metal of the platinum group or any mixture
of such metals.
The essence of the present invention accordingly consists in manufacturing
gas-igniters by calcining an intimate mixture of a salt yielding a refractory
oxide, a chloride of a metal of the platinum group a cyanide of a metal of the
platinum group and a chlorine-expelling agent, that is to say, a refractory acid
or a salt leaving behind such acid.
Both the cyanides and the chlorides may be used either in the form of uncom-
pounded or compounded or composite salts; examples of the latter are for
instance:
a Cyanide of barium and platinum (BaPtCy. + 4H2O); cyanide of magnesium
and platinum (2 MgPtCy. + 7H₂O); cyanide of ammonium and platinum ((NH4)2
PIC + 2H2O); cyanide of zinc, platinum and ammonium (ZuPtCy, + 2NH, +
H2O); cyanide of thorium and platinum (ThPt₂Cy³ + 16H2O), and the like, or
corresponding cyanides of the other metals of the platinum group.
b Chloride of thorium and platinum (PtCl + ThCl + 12H,O); chloride of
magnesium and platinum, chloride of ammonium and platinum (PICI + 2NHCI),
and the like, or corresponding chlorides of the other metals of the platinum group.
As refractory oxides, all oxides of the alkaline earthy metals and the earthy
metals may be used in the form of such salts as are decomposable by heat,
as for instance, nitrate of thorium, nitrate of magnesium, nitrate of zinc, and
the like.
As chlorine-expelling agents may be used; silicic acid, hydrofluoric acid,
fluosilicic acid, boric acid, phosphoric acid and the like, either as such or in
the form of decomposable compounds, such as alkaline silicates, chloride of
silicon, organic silicon compounds, soluble borates, soluble phosphates and the
like.
We prefer to use as most advantageous: Platinic chloride that is to say,
hydrogen-platinum chloride (H₂PtCl + 6H2O) together with the double
cyanide of barium and platinum (BaPtCy, + 4H₂O) as the metal-yielding
component, and nitrate of thorium as the refractory-oxide-yielding component,
in combination with silicic acid as the chlorine-expelling component. The
employment of silicic acid has in addition to its very energetic expelling action
on the chlorine, the important technical advantage that it enables by means
of the impregnation method usual in the manufacture of incandescent mantles,

page_text: shaped igniters to be manufactured in which a large surface is combined with
a great resisting power, to shocks, and permanence of shape.
In carrying out the invention in its most perfect form known to us we
proceed as follows:
A fabric of cotton, wool, silk, asbestos or the like is first impregnated with
a solution of water-glass (soluble silicate of potassium or sodium), and, after
cautious drying it is treated with a mineral acid, preferably hydrochloric acid,
whereby the alkaline silicate is decomposed, and its silicic acid caused to remain
behind in the gelatinous state. The thus silicified fabric is impregnated with
a watery solution containing 25 parts hydrogen-platinum chloride (platinic
chloride (HP C6H₂O) 6 parts double cyanide of barium and
platinum (Ba Pt Cy. + 4H20) and 19 parts of nitrate of thorium in 50 parts
water. After drying the impregnated silicified fabric is cut into pieces of
desired size and form, and then these pieces are exposed to the action of heat
so as to reduce the thorium nitrate to thoria, and the platinum salts to
platinum. Thus a withstanding refractory structure is obtained intermingled
with extremely fine particles of platinum.
The proportions for the mixture given in the above example are those which
we prefer to use, but may be varied within wide limits.
If it is desired to use the invention for manufacturing the igniting com-
position in the condition of an amorphous mass, this may be done by mixing
the aqueous solution of thorium nitrate and said platinum salts with pure
hydrated silicic acid, evaporating the mixture to dryness on the water-bath,
and calcining the residue, whereby a crumbly mass is obtained.
In like manner as above we proceed with the other component substances
cited as equivalents.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that
what we claim is:
1. Process for the preparation of igniters for gas by heating a mixture of salts
of platinum with refractory oxides or salts producing such, characterized by
the employment of chlorides of the platinum group in combination with cyanogen
salts of the platinum group in the presence of a refractory acid or a compound
yielding the same on heating, substantially as set forth.
2. A modification of the process characterized in Claim 1, in which a fabric
impregnated with silicic acid is immersed in a solution of hydrogen platinum
chloride, platino-cyanide of barium and nitrate of thorium, and incierated after
drying, substantially as set forth.
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester, and Birmingham.