An Improved Manufacture of Electrical Resistances.
Year: 1897

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 18 of the Patents, &c. Act, 1883) as allowed by the
decision of the Comptroller General of the 24th day of January 1899.
PROVISIONAL SPECIFICATION.
An Improved Manufacture of Electrical Resistances.
We, JOSEF FRANZ BACHMANN, Engineer, of VII Kaiserstrasse 81, Vienna,
ADOLF VOGT, Engineer, of V Zentagasse 41, Dr. JOSEF KIRCHNER, Chemist, I
Elisabethstrasse 3, ALBERT KÖNIG, Banker, of I Elisabethstrasse 3, CARL
CAMILLE WEINER, of I Elisabethstrasse 3, Gentleman, and Dr. ALEXANDER JÖNG,
Chemist, of 1 Openring 1, all of Vienna, do hereby declare the nature of this
invention to be as follows:-
This invention relates to a manufacture of electrical resistances, for regulating
electric currents, of artificial stone, such resistances being applicable for a great
variety of purposes such as for theatrical stage regulators, for main and shunt
current resistances, starting resistances for dynamos, motors, telegraph stations,
electric railways, arc lamps &c., also for apparatus for the generation of heat, such
as electrical furnaces, cooking stoves and utensils, electrically heated floors, walls
ceilings, smelting furnaces, crucibles &c.
These electrical resistances consist essentially of a non-conductor with which an
electrical conducting material is incorporated in such manner that by moulding
or casting the mass an artificial stone is produced which possesses a certain con-
duoting power adapted to the particular purpose for which it is to be employed.
As non-conductor may be used any known kind of artificial stone, the composi-
tion of which forms no part of the present invention. The conducting material
to be incorporated therewith can either consist of a material which in itself possesses
a certain conducting power, or of a material which by heating by itself or with
the addition of a reducing agent in the artificial stone, is converted into a body
having the desired conducting power.
In the following are given, by way of example, some artificial stone com-
positions that will serve as resistances of the kind described.
1. Any non-conducting artificial stone compound, such as cement, clay, gypsum
&c., is mixed with a conducting material such as carbon, graphite, metals, in
pulverulent condition, together with water, with or without a binding material
such as waterglass, zinc chloride, sugar or gum-solution &c., the mixture being
formed into a kneadable mass, and pressed into moulds or it is poured into the
same in a liquid condition, after which it is dried or burnt, or after drying it is
hardened by dipping into a solution, such as alum when using gypsum.
2. A suitable artificial stone material serving as non-conductor is mixed with
materials which by heating are converted into carbonaceous material or metals
and consequently become conductors, such as asphaltum, tar, cellulose, sugar,
bone-meal, and certain metallic compounds. These mixtures are pressed in

page_text: plastic condition into moulds, or are poured in viscous liquid form into moulds
and burnt; the stone being saturated one or more times with liquids such as sugar,
syrup &c., either before or after burning, for the purpose of increasing their density
and strength.
3. The artificial stone compound (preferably refractory metallic oxides, mortar,
quartz, spar &c.) is mixed with easily reducible metallic oxides or metallic salts.
for example, zinc oxide, copper or tin oxides, with the addition of water or a
liquid cementing material, and after kneading into a doughy condition it is
pressed in inoulds and the formed lilocks are finally burnt in an envelope of carbon
powder or other reducing agent, ör this can be previously mixed with the mass.
Dated this 25th day of June 1897.
ABEL & IMRAY,
Agents for the Applicants.
An Improved Manufacture of Electrical Resistances.
We, JOSEF FRANZ BACHMANN, Engineer, of VII Kaiserstrasse 81; Vienną;
ADOLF VOGT; Engineer, of V Zentagasse 41, Dr. JOSEF KIRCHNER, I
Elisabethstrasse 3, ALBERT KÖNIG, Banker, of Ì Elisabethstrasse 3; CARL
CAMILLE WEINER, of I Elisabethstrasse 3, Gentleman, and Dr. ALEXANDER JÖRG,
of I Openring 1, all of Vienna, 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 a manufacture of electrical resistances, for regulating
electric currents, made of a composition having the nature either of stone or of a
powder, such resistances being applicable for a great variety of purposes such as
rheostats, theatrical stage regulators, for main and shunt current resistances,
starting resistances for dynamos; motors, telegraphi stations, electric railways, are
lamps &c., also for apparatus for the transformation of electrical energy into heat,
such as electrical furnaces, cooking stoves and utensils, electrically heated floors,
walls; ceilings, smelting furnaces, crucibles &c.
These electrical resistances consist essentially of a non-conductor with which an
electrical conducting material in a finely divided condition is incorporated. By
suitably enveloping, moulding or casting, if necessary, in connection with a
suitable binding agent, a resistance is produced which possesses a certain con-
ducting power adapted to the particular purpose for which it is to be employed.
As non-conductor may be used any substance which is a non-conductor, or a
bad conductor of electricity, such as for instance, cement, clay, silica, gypsum,
metallic oxides, minerals etc. The conducting material to be incorporated with
these non-conductors can either consist of a material which in itself possesses a
certain conducting power, or of a material which by heating by itself or with the
addition of a reducing agent in the non-conductors, is converted into a body
having the desired conducting power.
In the following are given, by way of example, some compositions that will
serve as resistances of the kind described.
1. Any non-conducting compound, such as cement, clay, gypsum etc., is
intimately mixed with a conducting material such as carbon graphite, metals, in
binding material
pulverulent condition, together with water, with or without
such as waterglass, zinc chloride, collodion, sugar or gum solution &c., the mixture
formed into a kueadable mass and pressed into moulds or it is poured into the
same in a liquid condition, after which it is dried or burnt, or after drying it is
1.

page_text: hardened by dipping into a solution, such as alum, when using gypsum, or it is
treated with hardening agents.
2. A suitable compound made of non-conducting materials is mixed with
materials which by heating are converted into carbonaceous material or metals
and consequently become conductors, such as asphaltum, tar, cellulose, sugar,
collodion, bonemeal, or certain metallic compounds. These mixtures are pressed
in plastic condition into moulds, or are poured in viscous liquid form into moulds
and burnt, the stone being saturated one or more times with liquids such as
sugar, syrup, or with suitable hardening agents, either before or after burning,
for the purpose of increasing their density and strength. The impregnating
liquid is and remains a non-conductor.
3. A stone compound (preferably refractory metallic oxides, mortar, quartz,
spar &c.) is mixed with easily reducible metallic oxides or metallio salts,. for
example, zinc oxide, copper or tin oxides, when necessary, with the addition of
water or a liquid cementing material, and after kneading into a doughy condition
it is pressed in moulds and the formed blocks are finally burnt in an envelope of
carbon powder or other reducing agent, or this can be previously mixed with
the mass.
Instead of allowing the compound intended to form the resistance to solidify
and harden, this compound may be left in pulverulent condition and be arranged
within a suitably shaped hollow body. If for instance it is desired to produce a
resistance having the shape of a rod, fire-clay powder incorporated with the
conducting material (graphite) may be tightly packed in a glass-tube. By making
the envelope of such a resistance of two parts insulated from each other, this envelope
may be utilized for conducting the electric current to the resistance. Thus for
instance, an electrical cooking pot may be made in such a manner that two
metallic pots of different sizes are placed one within the other and the space between
the two receptacles is filled with the powder compound forming the resistance.
If the two receptacles are connected with the source of electricity the heating of
the contents of the cooking pot is obtained because the electrical current is obliged
to pass through the layer of powder between the two receptacles.
In either case the prepared compound made of a non-conductor or of a bad con-
ductor of electricity, employed either by itself or within a suitable envelope, must
be incorporated with a finely divided conducting material. It is by no means
necessary that the distribution of the conducting material should be absolutely
uniform throughout the whole extent of the resistance. Thus, for instance the
proportion of the conducting material may be modified in those parts of the
resistance in which the development of heat should be different from that in the
other parts. In all cases it is however necessary that the conducting material
should be in a finely divided condition and distributed throughout the whole body
or compound consisting essentially of a non-conductor. If it is desired to make
the resistance at certain parts of it acid-proof or the like, these parts are provided
with a suitable protecting coating, for instance with a glaze.
In this manner it is possible to produce resistances having the shape of handy
receptacles, suitable for cooking or heating purposes:
The proportions of the ingredients of all the above described compounds neces-
sarily vary between very wide limits, according to the degree of resistance which
it is required to afford. Thus in the case of a compound of alumina and graphite,
if a comparatively weak resistance is required the compound may consist mainly
of graphite, with a very small percentage of alumina; if on the other hand great
resistance is required, the proportions would be reversed.
As an example of an electrical resistance having very good conducting powers,
about 95 p.c. of graphite may be mixed together with about 5 p.c. of caolin in
water, and after thoroughly incorporating and kneading the same the mixture is
charged into moulds, dried and burnt at a high heat, when the mass becomes very
bard. If it is desired to still further increase the conducting power of the above
mass, it is saturated with syrup, tar, or the like and is then again burnt.

page_text: :
If the mass is required to afford greater resistance, the percentage of alumina
is increased and that of the graphite is reduced.
If it be desired to produce a resistance composed of alumina and graphite that
will be cohering without being burnt, then instead of using water for the mixing
and kneading, a solution of gum arabic and sugar in the proportions of two to one,
is employed. Resistances made of such a compound require to be exposed to the
air for some time for drying and they can then be heated to from 1100 to 150° C.,
producing a very hard mass that can be cut, turned, filed or polished. In practice,
a load of graphite and one of caolin are taken, and from these samples of varying
proportions are mixed together as above described, and their resistances determined
by experiment.
:
A tabular statement setting forth these proportions and their corresponding
resistances is then prepared, and this table can then be followed in preparing
resistances of any required quality from the said loads of graphite and caolin
In a similar manner the preparation of resistances from the other above
mentioned ingredients is proceeded with.
!..
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
!.
Electrical resistances made by the method hereinbefore set forth as the third
example from a mass which is a bad conductor or a non-conductor of electricity,
and in which is incorporated a suitable quantity of a good conducting metallic
substance, in a finely divided condition, for the purpose of regulating at will the
conducting power of the resistance, substantially as set forth.
Dated 17th day of December 1897.
ABEL & IMRAY,
Agents for the Applicants.