Improvements in Electric Heating Devices.
Year: 1895

page_text: Date of Application, 5th Dec., 1895-Accepted, 11th Jan., 1896
Improvements in Electric Heating Devices.
I, FERNAND LE ROY of 14 Rue Saint Georges, Paris, in the Republic of
France, 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 :-
:
The electric current which can now be easily obtained from central stations
which are erected in even unimportant towns affords a source of energy which
is both very convenient and powerful. At present this current has been mainly
utilized for lighting purposes and on a small scale as motive force for operating
machines for ventilation or the like, and the reason why the use of the electric
current has not become general for heating and cooking food arises from the
fact that all the apparatus at present employed both for heating and for cooking.
fulfil only imperfectly the requirements of ordinary life whilst being very,
expensive. They require besides a somewhat considerable expenditure of energy
and their cost is so high that, in spite of all the advantages presented, electric
heating cannot be employed except in a few special cases.
The various advantages which the use of electricity offers above all other methods,
such as gas, oil or coal are as follows:-
1. A total absence of smoke, smell, dirt or waste heat.
2. The heat is more equally distributed and the whole of the caloric produced is
utilized without loss such as results from the escape of unconsumed gas.
3. The utensils employed are botli convenient and safe, and there is a saving of
time and of labour.
Heating by electricity is obtained by causing the current to pass through thin
metallic wire conductors offering a great resistance to the current so that these.
wires become heated and transmit the heat by radiation. But these resistances
when heated to redness by the passage of the current become deformed, and oxidized
in contact with the air, and thus in a short time become useless. It has therefore
been found necessary to enclose them in an insulating paste which protects them
against atmospheric influences and thereby against oxidation. It is principally this
insulating paste which forms the object of the various patents taken out hitherto
for heating by electricity.
°
The defects of the apparatuses constructed according to these various processes
are numerous. The heat is transmitted from the incandescent wires to the
insulating substance which encloses them and then finally to the metallic surface
forming the apparatus itself (saucepan, boiler, radiator or other article); there is
therefore a double radiation which requires both more time and more energy than
in the case of apparatuses which are exposed directly to the source of heat. This
further necessitates the enclosing in the apparatus itself of the source of heat. It
therefore becomes necessary to purchase a whole fresh set of kitchen utensils to
which every household has to become accustomed. With this system it is in fact,
almost impossible to form an actual fire; the loss by radiation would be too
great. The sole apparatuses made are hermetically closed cases otherwise called
❝ heaters."
In all these apparatuses the heater is never apparent, and it is therefore not
possible to grill or to roast meat.

page_text: For the same reason the heating of rooms cannot be obtained except by means of
radiating plates which are difficult to work in, in the decoration of rooms and are
always of a somewhat disagreeable appearance. Further these apparatuses by
their construction are liable to rapid deterioration; at the end of a short time the
wires forming the resistance break and the apparatus becomes useless.
The invention which is the subject of the present application enables all the
inconveniences herein before mentioned to be remedied and allows of an electric
heating being obtained under excellent conditions both from the point of view of
working, as well as from the point of view of cost.
The essential and characteristic point of this invention consists in the use of
blocks of silicon through which the electric current is passed. These blocks are of
various lengths and sections according to circumstances. Their section may be
formed in any suitable curve, a circle or otherwise, or a rectangle or any other
geometrical shape. Ordinarily they have a section which is capable of providing
the greatest external surface. They are regulated according to the voltage and in
such a way as to absorb the whole as far as possible.
These blocks are exposed to the open air and are not covered with any coating.
The block of silicon inserted as a resistance in the circuit of the current is brought
to a red heat; under the action of this current it then develops a high temperature,
which is transmitted to articles placed in its proximity.
In practice the construction of heaters or "fires" according to this invention is
very simple. The accompanying drawing shows as an example one of the arrange-
ments which may be adopted. It is of course capable of various modifications.
The drawing represents an ordinary gas fire which is modified to allow of heating
by means of electricity. The blocks of silicon 1, 2, 3, 4 are held at each of their
ends by little platinum cones B, which form contacts; the contacts may of course
be made otherwise. These cones B are themselves supported by small electric
carbons A. The current passes from C to D flowing through the blocks of silicon
which are connected in series or otherwise as desired.
وو
When the current passes through the blocks of silicon the latter are brought to
a red heat and their heat is transmitted to articles placed above them. By placing a
saucepan or any other vessel on the "fire" the substance which it contains is
subjected to a high temperature absolutely as if the "fire" were fed by gas.
The silicon being unoxidizable in contact with air, the "fire can always be a
visible or an open one.
It is therefore easy to construct metal furnaces with open
fires as is done in the case of gas, on which any of the utensils at present employed
iu all kitchens may be used; the heat will be better utilized because the saucepans,
pans or boilers will be directly above the fire without the interposition of insulating
substances. It is therefore easy to arrange for grilling or roasting meat.
same way for heating rooms it is possible to construct stoves and fire places with
an open "fire."
In the
According to circumstances and the position in which the user is placed the
number of silicon blocks as well as their dimensions may be varied. In the accom-
panying drawing four only are shown but it is quite evident that such number is
only shown in an example. The blocks being of somewhat large dimensions they
are rarely broken with ordinary wear. Nevertheless should such be the case
they can easily be replaced.
.
To sum up, my invention consists in the use of silicon for the manufacture of
electric "fires" whatever may be the arrangements, forms or dimensions of these
fires, the arrangement shown on the accompanying drawing being only shown as an
example.
These "fires" may be utilized for heating rooms similarly to the stoves at present
employed, or for heating any vessels placed above them as with gas or coal stoves.
In the first case the apartment is heated by the direct radiation of the silicon
blocks, and in the second case the heat is transmitted to the substances contained
in the vessels.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what 1
claim is :-
1. The use and application of silicon for forming electric heaters or "fires" of
any shape, form or dimensions, and whether they are applied to the heating of
apartments or to the heating of vessels placed thereon.
2. In electric heating devices, the combination of a series of silicon blocks, a
series of carbon or other conducting blocks, and a series of small platinum cones
attached to said conducting blocks and supporting the silicon blocks, substantially
as and for the purpose set forth.
Dated this 4th day of December 1895.
WM. P. THOMPSON & Co.,
Of 6 Lord Street, Liverpool, Agents for the Applicant.