Improvements in Cooking Apparatus.
Year: 1895

page_text: Date of Application, 17th Aug., 1895
Complete Specification Left, 7th May, 1896-Accepted, 13th June, 1896
Improvements in Cooking Apparatus.
I, ALFRED ROTHENBACH, of 180, Limmatstrasse, Zurich, in the Republic of
Switzerland, Engineer and Gas-manager, do hereby declare the nature of this
invention to be as follows:-
This invention relates to that class of cooking apparatus which are employed to..
prevent cooking vessels and their contents from becoming cold when taken off the
fire and in which the heat picked up from the fire is retained for a long time
for the purpose of gradually simmering the food without the use of any kind
of fuel.
According to this invention the body of the said apparatus is formed with
cavities for the purpose utilizing air, which as is well known is a bad conductor of
heat, as a means for preventing the radiation of heat.
Fig. 1, of annexed drawing, is a longitudinal section and Fig. 2 a section of a
detail of an apparatus constructed in accordance with one form of my invention.
The cylindrical body of the apparatus is formed of two sheet metal jackets a & b
with an annular space between the same which at the upper end is closed by a
ring c of wood and at its lower end by a bottom. In order to increase the isolating
properties of the air in this annular space, it is divided in two by means of the
partition m which forms separate air volumes the said partition being made of
material which is a bad beat conductor for instance of cardboard, celluloid and the
like. The high temperature which the inner air volume picks up gradually from
the cooking vessels placed into the apparatus is checked from radiating to the
outer air volume by means of the said partition and itself increases the isolating
action of the inner air volume outwards.
d corre-
The bottom of the apparatus consists of two sheet metal plates d & e,
sponding in size with the outer jacket a, aud e with the inner jacket 6 and of a
disc made of a material which is a bad heat conductor, such as wood, and is
employed between the said two plates. The disc fills up the space between the
latter only partially and thus gives another air volume which prevents loss of heat
from the inside to the outside of the apparatus.
By preference the upper plate e formed with raised parts el (for instance by
stamping the same) which retain the lowest of the cooking vessels put into the
apparatus a little distance above the bottom in such a manner as to provide between
the same also an isolating air volume.
The main lid of the apparatus forms an air cap 9 dished outwardly, the base of
which is formed of layers of material which is a bad heat conductor. In Fig. 1
the said layers consist of a cardboard and a felt disc & i. The latter are
secured to the.
prevented from being pressed in by means of a sheet metal disc
middle of the cap g by means of a stud k, the disc being less in diameter than the
said felt disc so as to allow the latter of tightening against the face of the wood
ring c.
For the purpose of closing the apparatus as hermetically as possible a secondary
lid is employed in the same piston like and formed of a number of discs o of pliable
and bad heat conducting material, such as fabric, felt and the like, which are
clamped together by plates n, n', made for instance of sheet metal and connected-
together by means of studs.

page_text: The sheet metal discs are in diameter a little less than that of the fabric or felt
discs, so that the edges of the latter may serve as a packing in the apparatus.
These edges are bound with a strip p of pliable material, such as fabric, the edges
of which are secured underneath the plates n, n', see Fig. 2.
Dated this 16th dor of Suanst 1905
TO COOK Apparatus.
I, ALFRED ROTHENBACH, of 180, Limmatstrasse, Zurich, in the Republic of
Switzerland, Engineer and Gas-manager, 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 that class of cooking apparatus which are employed to
prevent cooking vessels and their contents from becoming cold when taken off the
fire and in which the heat picked up from the fire is retained for a long time
for the purpose of gradually simmering the food without the use of any kind
of fuel.
According to this invention the body of the said apparatus is formed with
cavities for the purpose of utilizing air, which is well known, is a bad conductor of
heat, as a means for preventing the radiation of heat.
Referring to the drawings filed with the Provisional Specification Fig. 1 is a
longitudinal section and Fig. 2 a section of a detail of an apparatus constructed in
accordance with one form of my invention.
The cylindrical body of the apparatus is formed of two sheet metal jackets a & b
with an annular space between the same which at the upper end is closed by a
ring c of wood and at its lower end by a bottom. In order to increase the isolating
properties of the air in this annular space, it is divided in two by means of the
partition m which forms separate air volumes, the said partition being made of
material which is a bad heat conductor for instance of cardboard, celluloid and the
like. The high temperature, which the inner air volume picks up gradually from
the cooking vessels placed into the apparatus, is checked from radiating to the
outer air volume by means of the said partition and itself increases the isolating
action of the inner air volume outwards.
The bottom of the apparatus consists of two sheet metal plates d & e, d corre-
sponding in size with the outer jacket a and e with the inner jacket band of a
disc made of a material which is a bad heat conductor, such as wood, and is
employed between the said two plates. The disc f fills up the space between the
latter only partially and thus gives another air volume which prevents loss of heat
from the inside to the outside of the apparatus.
By preference the upper plate e is formed with raised parts e¹ (for instance by
stamping the same) which retain the lowest of the cooking vessels put into the
apparatus a little distance above the bottom in such a manner as to provide between
the same also an isolating air volume.
:
The main lid of the apparatus forms an air cap g dished outwardly, the base of
which is formed of layers of material which is a bad heat conductor. In Fig. 1
the said layers consist of a cardboard and a felt disc & i. The latter are
prevented from being pressed in by means of a sheet metal disc l, secured to the
middle of the cap g by means of a stud k, the disc 1 being less in diameter than the
said felt disc so as to allow the latter of tightening against the face of the wood
ring c.
For the purpose of closing the apparatus as hermetically as possible a secondary

page_text: lid is employed in the same, piston like, and formed of a number of discs o of
pliable and bad heat conducting material, such as fabric, felt and the like, which
are clamped together by plates n, n', made for instance of sheet metal and connected
together by means of studs.
The sheet metal discs are in diameter a little less than that of the fabric or felt
discs, so that the edges of the latter may serve as a packing in the apparatus.
These edges are bound with a strip p of pliable material, such as fabric, the edges
of which are secured underneath the plates n, n', see Fig. 2.
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 I
claim, is-
1st. A cooking apparatus having an outer and an inner cylindrical jacket and
an air volume or volumes between the same and the bottom of which is formed
double and contains also an air volume, as well as the lid, all substantially as
described.
2nd. A cooking apparatus having cavities in its body for utilizing air as heating
medium and provided with a sliding or secondary lid, formed of two discs of
flexible material such as cloth, felt and the like, the edges of which are bound with
a strip of pliable material and which discs are clamped between two plates of less
diameter and form a packing or tight joint internally, all substantially as set
forth.
3rd. A cooking apparatus having an outer and an inner cylindrical jacket with
an air volume or volumes between and a bottom formed double as well as a lid both
containing an air volume, in combination with a sliding or secondary lid formed of
two discs of flexible material, such as cloth, felt and the like, the edges of which
are bound with a strip of pliable material, such as cloth, felt and the like and
which discs are clamped between two plates of less diameter and form a packing or
tight joint inside the cooking apparatus, all substantially as set forth.
4th. A cooking apparatus having cavities in its body for utilizing air as heating
medium, which body is formed of two sheet metal jackets a &b and with an
annular space between, the latter being divided into two compartments by a
partition m formed of material which is a bad conductor of heat for the purpose
of providing two separate air volumes, all substantially as set forth.
5th. A cooking apparatus having cavities in its body for utilizing air as heating
medium and a bottom which is formed of two sheet metal plates d & e between
which is employed a disc f formed of material which is a bad heat conductor, such
as wood, the said disc filling up the space between the said plates only partially,
for the purpose of providing an air space, all substantially as set forth.
6th. A cooking apparatus having cavities in its body for utilizing air as heating
medium and in which the main lid is dished out cap like, forming the base of the
said lid with layers of material which is a bad conductor of heat, all substantially
as set forth.
LUX OLI UXY H ALY
1000
LOWU
D. NOX OLIY MY IONUA
F. BOSSHARDT & Co.,
4, Corporation Street, Manchester, Agents to Applicant.