Improved Means for Electrically Heating Second Class Electric Con- ductors serving as Incandescence Bodies for Imparting to them the Requisite Conducting Power.
Year: 1898

page_text: Date of Application, 23rd Apr., 1898-Accepted, 18th June, 1898
COMPLETE SPECIFICATION.
Improved Means for Electrically Heating Second Class Electric Con-
ductors serving as Incandescence Bodies for Imparting to them
the Requisite Conducting Power.
I, MAX DÉRI, of 1 Reichsrath-strasse, 3, Vienna, Engineer, 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:-
Dr. Nernst has proved that, the known refractory substances such as calcium-
oxide, magnesia, aluminium oxide, zirconium oxide, the oxides of the rare earths
&c., which possess great illuminating power when heated to incandescence, become
conductors of electricity when heated to a certain temperature, and can then be
rendered luminous in the highest degree by an electrical current of sufficient
strength.
My present invention relates to means for raising such second class conductors
(electrolytes) to the requisite temperature for rendering them conductors for the
above purpose, by the employment of small quantities of an electric current of
ordinary pressure.
The invention consists in the employment for the above purpose of an electrical
heating body of very weak conducting power so as to offer so great a resistance to
the current that the resulting heat into which the current is transformed, will be
transmitted in sufficient degree to the conductor of second class constituting an
incandescence body surrounding the heating body for imparting to this the requisite
conducting power, the said heating body being then allowed to remain included in
the electric circuit with the incandescence body.
The well known electrical heating bodies such as are employed for electrical
cooking and heating apparatus are not suitable for the above purpose, and they
would not withstand the high temperatures, to which the said second class con-
ductors have to be raised for producing the required light.
The small body which, is to serve as electrical incandescence body and which
consists of the heating appliance and the surrounding second class conductor
capable of producing light, must, in the cold condition, offer to the electric current
a specific resistance which is many million times greater than that of metal wires
and many thousand times greater than that of carbon filaments.
For effecting the necessary heating of the small incandescence body, only a
small amount of electrical energy (a few watts) is necessary if this is entirely con-
verted into heat and if such heat is transmitted as completely as possible to the
incandescence body.
For this purpose the heating body is made of a mixture of refractory non con-
ductors, or of second class conductors mixed with refractory metals of known
kinds or with carbon in a very fine state of subdivision, the proportions employed
being such that after the compound has been brought into a plastic form and con-
verted by pressing and drawing and then heating to redness, into filaments rods or
small tubes, it will offer the requisite high resistance to the electric current.
If the materials (first and second class conductors) are very finely subdivided
and thoroughly mixed together, 1 to 10 parts of carbon to 100 parts of the second

page_text: class conductor or 0.01 to 0.1 parts of a metallic conductor to 1000 parts of the
second class conductor will be found to give good results. If an incandescence
body which consists of such a heating body surrounded by a second class conductor
is subjected to a normal supply of electrical energy, only a weak current will at
first pass through the heating body, proportionate to the high resistance thereof,
which current will be converted into heat and this will be transmitted to the
surrounding electrolyte. The latter will thus become a conductor and will allow
sufficient current to pass through it to render it incandescent and luminous.
The heating body will not cease to conduct the current after it has heated the
electrolyte, but no appreciable loss of energy will be caused hereby, as the amount
of current thus passing will be very small in comparison to that consumed by the
incandescent electrolyte.
The incandescence body formed by the heating core and incandescence mantle is
preferably enclosed in a globe exhausted of air or filled with indifferent gases like
ordinary electric glow lamps.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
In combination with electrical glow lamps formed of second class conductors
the use, for electrically heating the latter to the requisite temperature for con-
stituting a conductor, of an electrical heating body situated within the electrolyte,
which heating body consists of a mixture of refractory substances that are bad
electrical conductors with so small a quantity of carbon or of very refractory
metals, that when it is subjected to a current of normal pressure, it will only allow
the passage of a very small amount of current in comparison to that consumed by
the incandescent electrolyte mantle, and can therefore be allowed to remain in
circuit together with the latter while in action.
08 1
A 1900