An Improved Electric Cooking and Frying or Roasting Apparatus.
Year: 1896

page_text: Date of Application, 24th June, 1896-Accepted, 29th Aug., 1896
An Improved Electric Cooking and Frying or Roasting Apparatus.
A communication by THE CHEMISCH-ELEKTRISCHE FABRIK "PROMETHEUS
GESELLSCHAFT MIT BESCHRANKTER HAFTUNG, of Bockenheim, Frankfort-
on-the-Main, in the Empire of Germany, Electricians.
.I, GEORGE CECIL DYMOND M.I.M.E., of the Firm of W. P. Thompson & Co.,.
of 6 Lord Street, Liverpool and 6, Bank Street, Manchester, both in the County
of Lancaster, 118 New Street, Birmingham in the County of Warwick, and
322 High Holborn in the County of Middlesex, 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:-
This invention relates to cooking.and roasting apparatus in which the necessary
heat is produced by means of electrical energy. Hitherto such apparatuses were
provided with metal wires or metal strips which were embedded in a peculiar manner
in enamel, and the current was conducted through these wires or strips. Such
apparatuses are very expensive to construct and require very many repairs, because
the metal wires, which are raised to a red heat, easily melt at thin places, and
because in consequence of the different co-efficients of expansion of the metal wire:
and of the insulating material, the latter cracks and thus allows air to obtain access
to the incandescent metal. In the latter case there takes place naturally a
destruction of the metal wires or strips by oxidation.
In this improved cooking and roasting apparatus the above drawback is entirely
removed by providing the surface of the cooking and roasting apparatus, (which
surface consists of suitable insulating material) with layers or strips of the precious
metals after the manner of the ceramic precious metal decoration, the ends of which
layers or strips are provided with suitable contact devices for the supply of the;
electric current.
In these improved cooking and roasting apparatuses the layer of the precious
metal is so thin that any variable expansion caused by the heat has no effect on the
material of the cooking or roasting apparatus or rather on the enamel or glaze
surfaces thereof.
Further the mass of the layers of precious metal in proportion to that of the;
insulating substance is so small that the latter absorbs the entire heat resulting:
from the electric energy and thus renders it serviceable for boiling or roasting
purposes.
By this invention there is obtained on the one band an extremely simple con-
struction and great durability of the cooking and roasing apparatus and on the
other hand an essentially increased degree of efficiency. The improved cooking-
or boiling and roasting apparatuses are provided with a protective casing or cover:
from which the supply of current to the layers of precious metals takes place by
means of spring contact devices.
The improved cooking and roasting apparatuses are shown in the accompanying!
drawings in which :-
:
Figures 1-8 show cooking annaratuses of various forms:

page_text: Figures 9 & 10 show a round shallow pan; and
Figures 11-13 a four cornered roasting pan.
The actual vessel a is provided in the manner shown in the drawing with the
above mentioned layers or strips 6 & 1 of the precious metals.
The lower
In Figures 1 & 2 the strips b of precious metal are arranged spirally on the
bottom, and the strips of precious metal on the edge surfaces.
part of the vessel is surrounded by a protective casing c, which is attached to
the vessel a by means of an annular flange d. The strip b is continued on the
edge surface by a central strip a and a side strip y. To the latter the strip b¹
is attached, which strip & extends round the edge surface to another side strip z.
As shown in Figs. 3 & 4 the protective casing or cover c is provided with three
clamps or binding screws x, y, to which the current supply wires are attached.
To the clamps x, y, z springs x, y, are attached which rest on the ends of
the strips x, y, z, which latter are preferably made somewhat thicker at the points
of contact. If the conducting wires be inserted in the clamps ¹ & y' current
passes from only through the strips b. If the conducting wires be inserted in
the clamps & current passes in series through the resistance layers b & b
The clamps & y' may also be connected in common with the one supply wire and
the clamp z with the other in order to allow the two strips b & 6' to be traversed
by the current in parallel.
Figs. 5 & 6 show a milk pot in which the resistant strips and clamps and contact
springs are arranged as in the cooking pot shown in Fig. 1, whilst the actual pot a
is entirely surrounded by a protective casing c.
Figures 7 & 8 show another pot in which again only the lower part is surrounded
by a protective casing c. The resistant material 6 is arranged on the bottom
surface and partially on the edge surfaces in the form of a band. Between the
two end strips a & y there is an interstice extending to the centre of the bottom.
The contact springs and clamps are again arranged in the manner described in
Figs. 1-4.
Figs. 9 & 10 show a round frying pan. The inner vessel a is provided with the
resistance strip b, which is essentially arranged on the bottom surface and extends
on the edge surfaces into strips & y. The vessel a is encased with a protective
casing c, which is attached to the vessel a by means of the annular flange d, and has
again clamps and contact springs. A handle f is provided to allow of the frying
pan being more conveniently manipulated.
Figs. 11 & 12 show a four cornered roasting pan.
Fig. 13 shows a casing opened out into a single plane.
The bottom surface of the inner vessel a is provided with the resistance layer b
and the edge surface with the resistance layer 6' as is clearly visible from Fig. 13.
The ends (x, y, z) of the resistance layers resting on one edge surface are again
connected by contact springs with conducting clamps as shown in Fig. 11 as regards
springs y & y².
In all the arrangements herein before described it is of importance that the layers
formed in the manner of ceramic precious metal decoration and traversed by the
current be arranged on insulating surfaces of the cooking and frying or roasting
apparatuses and be connected with the current supply wires. The cooking and
frying or roasting apparatuses can therefore be formed of metals coated with enamel
or other suitable insulating material or may be made entirely of insulating material.
Precisely because the mass of the resistance layer is so extremely small in propor-
tion to the mass of its support, almost the entire heat is utilized for purposes of
cooking and frying, so that these improved cooking and roasting apparatuses yield
a useful effect never hitherto attained.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
An electric cooking and frying or roasting annaratus.
characterised by

page_text: layers (6 & 6) of the precious metals being formed in the manner of ceramic gold
decorations on insulating surfaces of a vessel (a), said vessel being surrounded by a
protective casing (c), and the supply of current being obtained by means of spring.
contact devices.
Dated this 23rd day of June 1896
WM. P. THOMPSON & Co.,
Agents.