Improvements in Cooking Vessels.
Year: 1892

page_text: Date of Application, 10th May, 1892-Accepted, 11th June, 1892
COMPLETE DIECIFICATION.
Improvements in Cooking Vessels.
A communication by RICHARD CLARENCE ANDERSEN, Manufacturer, and JOHN
LAW MARSHALL, Gentleman, both of Lincoln, in the County of Lancaster
and State of Nebraska, United States of America.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E. of the Agency for
Foreign Patent Solicitors, 6 Lord Street Liverpool, and 6, Bank Street,
Manchester both in the County of Lancaster, and 323 High Holborn in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :—
The invention has for its object improvements in cooking vessels.
It may be understood from the following description, reference being had to the
accompanying drawings, which show, in vertical central section, one form of the
improved cooking utensil.
Numeral 1 indicates the exterior and 2 the interior wall separated from the
exterior by a space 3, which preferably surrounds the vessel on all sides. The
upper end of the wall 2 of the interior receptacle flared outwardly and joined to
the exterior wall, and a single cover is employed both for the interior and exterior
receptacle. 4 are apertures whereby the space 3 and the interior of the vessel
freely communicate. 5' denotes a cover which should be made to fit closely. In
the case of a coffee pot or other small vessel having a comparatively small mouth,
a screw cap cover is suitable. The cover should be substantially steam tight.
The interior wall 2 is closed by a bottom 21 which does not extend as low as
wall 1.
5 indicates an annular plate provided with upturned lips 6, which plate is
secured to the outer wall 1 of the vessel, the upturned lips or flanges being
made to bear against the bottom 2' of the interior of the vessel to support the
same. The space 7, surrounded by the annular plate, and the bottom 2', are
designed to receive the heat of a gas or oil flame or of a hot stove plate. The
vessel, however, may be used over any kind of a fire and on any stove.
In the
annular plate 5, feet 8 are formed, preferably by indenting the metal. These
feet support the plate above the stove top and have the effect of enlarging the
superheating space 7.
The operation of the improvement is as follows:-
Articles to be cooked having been placed in the vessel, and the latter tightly
covered and placed over a fire, steam is quickly generated from the water in the
vessel, and, rising to its upper part, is forced into the space 3 and down toward
the bottom of the vessel. The exterior wall 1, being exposed to atmospheric
influences, is cooler than the interior of the vessel and also cooler than the steam
which descends in contact therewith and which is therefore condensed or partially
condensed thereby. The steam thus partially cooled descends towards the
bottom of the vessel and comes in direct. contact with the flame of the burner
or with the hot plate of the stove and is at once converted into steam of
higher pressure and ascends next to the interior wall 2. It is found in practice
that steam does not escape into the air in any appreciable amount. None is
visible, and odours of food are not perceptible. It is also found that food is more
thoroughly cooked in a given time than in ordinary vessels. This is attributable
to different causes. The inner receptacle is surrounded by a steam or air space
which defends it against radiation or against the cooling effect of external air
currents. The downward escape of the steam is opposed by the heat of the
flame or of the hot stove plate tending to superheat or expand it in the space

page_text: immediately below the inner vessel. This also tends to raise the pressure in the
interior of the vessel a little above atmospheric pressure so that its heat is
thereby increased and the loss of such heat is prevented by the outer vessel as
stated. Practical experiment has demonstrated the utility of the device, and the
claim of invention is not based solely upon the theory of operation herein set
forth, though it is probably correct.
Vessels with double walls enclosing a space which communicates with the top
of the vessel and with the interior of the stove are not new, and such construction
is not broadly claimed. It is characteristic of the present improvement that it
provides a space 7 under the bottom 2' of the vessel and above the foot of its outer
wall, whereby a superheating or expansion chamber is provided above and near the
level of the bottom or annulus, 5; said annulus being without a pot hole extension
and the sole bottom of the utensil and adapted to rest on the top of a stove, the
central part of said bottom being cut away, whereby the centre of the bottom of
the inner receptacle is exposed to direct radiation either from the stove top or from
the stove hole.
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 :-
1. The double walled vessel provided with a tight cover and having its walls
joined at their tops, the inner wall being perforated, near its upper end, and the
outer wall having secured to its foot the annulus 5, extending under the bottom of
the inner receptacle and provided with upward projections 6 bearing against the
bottom of said inner receptacle at points approximately midway between the
periphery and centre of said bottom, substantially as set forth.
2. The cooking vessel having an inner receptacle and provided with a steam
tight cover and with two walls 1 and 2 fixed together, the former extending below
the latter and having for its bottom the horizontal plate 5 extending immediately
under the said receptacle and provided with upturned lips 6, said plate being
adapted to enclose a space above the foot of the outer wall and below the bottom
of the inner receptacle in communication with that immediately below the said inner
receptacle and also in free communication with the interior of the latter at its upper
part, the central part of the bottom of said outer receptacle being cut away,
substantially as set forth.
3. The cooking vessel provided with a steam tight cover and with two walls, 1
and 2, fixed together, the former extending below the latter and having for its
bottom the plate 5 provided with the feet 8 and upturned lips 6, and adapted to
support the utensil by resting on any part of a stove top and to leave the centre of
the bottom of the inner receptacle exposed to direct radiation from said top, the
space immediately under the space 5 being in direct communication with the
bottom of the inner receptacle and also in communication with the interior of said
inner receptacle, substantially as set forth.
Dated this 9th day of May 1892
WM. P. THOMPSON & Co.,
Agents for the Applicant.