IMPROVE- MENTS IN AND RELATING TO APPARATUS FOR COOKING, DIGESTING OR SIMILAR PURPOSES
Year: 1884

page_text: ⚫ I, HIRAM STEVENS MAXIM, of 57 Hatton Garden, in the County of Middlesex,
Mechanical Engineer, do hereby declaro the nature of my Invention for "IMPROVE-
MENTS IN AND RELATING TO APPARATUS FOR COOKING, DIGESTING OR SIMILAR
PURPOSES" and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
My Invention relates to apparatus for cooking, digesting or similar purposes.
Its chief object is to so construct such apparatus that the supply of heat to the
food or other substance contained therein will be automatically regulated in the
manner hereinafter described.
It is essential in cookery that a certain temperature, varying according to the
nature of the food to be cooked, should not be exceeded. For many kinds of food
it is found that a temperature of two hundred and twelve (212) degrees Fahrenheit
is too high to produce the best results, because it congeals the albumen and renders
some kinds of food hard, especially salted meat and eggs, while it disintegrates
vegetables and reduces them to pulp; moreover in other kinds of food (coffee for
example) it destroys or deteriorates the flavor. Any food containing water (which
exists more or less in nearly all kinds of food) can be readily heated to a
temperature of 212 degrees, and its temperature will not rise beyond this point
until the water it contains has been evaporated. But after this evaporation has
taken place, the temperature will rise considerably, and the food will be burnt if
great care is not exercised in regulating the heat applied thereto.
One object of my present Invention is to so construct cooking apparatus that,
when the food contained therein has been heated to a maximum temperature, the
supply of heat thereto will be automatically cut off or diminished, or regulated so
as to maintain such temperature. This regulation is effected by the expansion and
contraction of a closed chamber or casing containing water or other liquid, which
expansion and contraction are due to the variations of pressure within the said
chamber or casing, when heat is applied thereto. The maximum temperature may
be fixed at two hundred and twelve (212) degrees or at any suitable point above or
below this point.
When food is cooked by means of gas, it is found that cooks often burn much
more gas than they require. In boiling some kinds of food, for example, they add

page_text: Imposto www autony to apparatus for Cooking, Digesting, &c.
plenty of water as evaporation takes place, without considering the quantity of
gas required to evaporate this water. Moreover they allow the gas to burn when
not required for cooking purposes, or forget to turn it off, so that it frequently
burns all night, thus causing great waste of gas.
My improved apparatus prevents this waste by diminishing the supply of gas
when a certain temperature has been reached. Moreover, when the maximum
temperature is fixed at a point below 212 degrees my apparatus prevents the
burning of the food.
In the accompanying Drawings I have shewn various forms or modifications of
my improved apparatus.
Figure 1 is a vertical central section shewing my said apparatus adapted for
boiling various kinds of food.
Figure 2 is a horizontal section on the line x, x, Figure 1.
Figure 3 is a plan of a portion of the apparatus shown in Figures 1. and 2.
Figure 4 is a side elevation, partly in section, of another portion of the said
apparatus.
Figure 5 is a vertical central section showing my apparatus adapted for frying.
Figure 6 is an end elevation, and
Figure 7 a vertical longitudinal central section, shewing my said apparatus
adapted for baking.
Figure 8 shews my apparatus, in vertical central section, adapted for digesting
food or for similar purposes, and
Figure 9 is a vertical central section shewing the said apparatus adapted for
heating water or other liquids.
Like letters indicate corresponding parts throughout the Drawings.
a is the vessel or pan to receive the food to be cooked, and b is an annular
chamber which is partly filled with liquid to regulate the temperature of the
contents of the said pan or vessel in the manner hereinafter described. In the
forms of apparatus shewn in Figures 1 to 7, this chamber is formed by surrounding
the vessel or receptacle a with a casing c. d is a pipe for the supply of gas to the
apparatus.
The apparatus shown in Figures 1 to 4 is designed for heating the food to &
temperature not exceeding two hundred (200) degrees Fahrenheit. The vessel a
and casing c are preferably made of tinned wrought iron plates commonly known
as "four cross tin;" and the said vessel and casing are rivetted together at their
upper ends. The vessel or receptacle a is provided with a cover or lid a' which
may be of wood or other suitable material. e is an exterior casing (which may be
of wrought iron) for preventing loss of heat from the space around the casing c.
For the purpose hereinafter explained, the bottom c¹ of the casing c is so
constructed and arranged as to be capable of acting under, and by reason of,
variations of pressure, in a manner which may be readily understood by reference
to an aneroid barometer. f is a stand or support for the said vessel and casings.
The said stand or support carries a Bunsen-burner which is constructed as
shewn, that is to say :-g is a tube which is perforated at g¹ for the admission of
air. In this tube is fitted a piston h carried by a rod or spindle i, the lower end of
which forms a valve for closing the orifice 92 whereby the gas from the pipe d
enters the tube g. The piston h is made with perforations h₁ for the passage of
gas from the lower to the upper part of the tube g. The spindle is fixed at its
upper end to a cap ; made in the form of a double cone and having perforations 71
through which issue the jets of mixed air and gas by whose combustion the heat
is generated. This cap j fits on the upper end of the tube g so as to be free to
slide thereon, and a spring k is placed upon the said tube. This spring bears at its
lower end against a fixed collar g³ and at its upper end against the cap j, and
tends to force the said cap and the spindle i upward so as to open the valve-
orifice g³. The upper part of the cap j, therefore, normally bears against the
under side of the bottom or diaphragm c, and the orifice g² is normally open.

page_text: d
The operation of this apparatus is as follows, viz. :-an ordinary stop-cock on the
gas supply pipe & having been opened and the jets of gas and air from the cap j
ignited, the water or other liquid in the chamber 6 will be heated, and, as the
temperature thereof rises, the pressure within the said chamber will force or bulge
the bottom c¹ of the casing c downward so that it will press upon the cap ; and
thereby close, or partially close, the orifice g. When the pressure in the chamber b
decreases, the spring k will react and open the said orifice. The supply of gas will
thus be regulated and a uniform temperature maintained in the apparatus. By
employing the chamber b partially filled with liquid, I obtain the additional
advantage of causing the heat to be uniformly applied to the exterior of the
vessel a.
It is obvious that if the temperature of the food placed in this apparatus is not
to be raised above two hundred (200) degrees, there must be a partial vacuum in
the annular space or chamber 6 when the apparatus is cold and the bottom or
diaphragm c must then be slightly forced or bulged inward or upward by the
external pressure of the atmosphere.
In the apparatus shown in Figures 1 to 4, I provide a spring 1 to strengthen
the bottom of the casing c and increase its flexibility as well as to partially
counteract the external pressure of the atmosphere; this spring is fitted inside the
chamber b so as to bear against the bottom c¹ of the casing c, and is held in place
by the stops c* rivetted to the said casing.
An increase of pressure in the chamber b tends to flatten the bottom of the
casing c or to force or bulge the same downward and thus close, or partially close,
the orifice g².
m is a pipe for supplying a small jet of gas, for the purpose of re-lighting the
gas escaping from the cap i should the orifice g³ be completely closed and again
opened by the action of the apparatus. This pipe extends from the supply pipe &
at a point between the orifice g* and the aforesaid ordinary stop-cock. The supply
of gas to this pipe m is regulated by means of the screw n.
The modification of my apparatus shown in Figure 5 is designed for use under &
pressure of say forty or fifty pounds per square inch, and partly intended for
cooking any kind of food which is not injured by being raised to the temperature
corresponding with such pressure; but it may be used for other kinds of food if
they are not left in, or upon, the apparatus after the water they contain has been
evaporated. In this modification the vessel a and the cylindrical part of the
casing c are made in one piece, the said vessel being in the form of a shallow pan.
In Figures 6 and 7 I have shown a further modification of my apparatus wherein
the vessel a is arranged with its longitudinal axis in a horizontal position and is
heated by a series of gas jets issuing from the pipe d. The supply of gas is
regulated automatically by the action of the internal pressure upon the end or
diaphragm c, which pressure forces or bulges the said end outward so that it closes
the valve o in the pipe d. p is an exterior casing enclosing an annular flue-space
communicating with a funnel or chimney p' for the escape of the heated air and
products of combustion. I may, if desired, provide two or more pressure-chambers
for the purpose above described.
I
In Figure 8 I have shewn my apparatus adapted for digesting, cooking or boiling
food or other substances under a pressure greater than that due to the atmosphere.
In this form of my apparatus I dispense with the casing c above described.
provide the vessel a with a lid or cover q so fitted to the vessel as to make a tight
joint when properly closed. This cover is secured by a screw passing through a
bridge-pieces having lugs & which enter recesses or cavities in the sides of the
vessel a.
The pressure in the interior of the vessel a causes the bulging of the
bottom or diaphragm c¹ so that its centre acts upon the cap; and the rod or spindle
connected therewith to close, or partially close, the valve-orifice as above described.
I prefer to make the bottom of the vessel a corrugated to facilitate this action. It
will be seen that, in this form of my apparatus, the interior of the vessel a serves

page_text: the double purpose of the recipient for the material to be cooked or boiled and also
as the pressure-chamber which regulates the heat.
Figure 9 illustrates the adaptation of my apparatus for heating and automatically
regulating the temperature of a continuous supply of water or other liquid. The
vessel a is, in this apparatus, provided with a series of tubes a¹. The pressure-
chamber b is formed by a tube c* passing through the vessel a, which tube is closed
at the top and has, at its lower end, a bell-shaped extension c³, the bottom of which
is closed by a flat or corrugated plate or diaphragm c¹. The vessel a is provided
with inlet and outlet pipes t, t¹ for the water or other liquid. A casing p surrounds
the vessel a and is provided with a chimney or flue p¹ for carrying off the products
of combustion. The said casing extends below the bottom of the vessel a so as to
form a space for enclosing the heat from the gas-burner and preventing the escape
thereof otherwise than through the said tubes.
The chamber b, in this form of my apparatus, is partially filled with alcohol or
other volatile fluid which, when heat is applied to the bottom or diaphragm c¹, will
be more or less vaporized, and will thus generate pressure within the chamber b.
This pressure will force or bulge outward the plate or diaphragm c¹ and cause the
same to act as above described; upon the gas-valve to close, or partially close, the
same, and regulate the supply of heat. By these means, if the ordinary stop-cock
in the gas supply pipe is properly adjusted, the temperature of the water or other
liquid in the vessel a will be kept constant, or nearly so, that is to say, while no
water is being drawn from the vessel a, the vapour will maintain the pressure in
'the chamber b and the burner-valve will be kept in such a position as to prevent
the supply of more than sufficient gas to raise the temperature to the desired limit,
and when any quantity of water is drawn from the said vessel and cold water
begins to flow into the same, the reduction of temperature will immediately cause
the condensation of the vapour and diminution of pressure in the chamber b, so
that the spring k will open the gas-valve. Thus the heater will be automatically
so controlled as to ensure its iminediate action in response to the requirements of
the apparatus.
い
I may provide the said apparatus with one, two or more tubes or chambers for
containing the volatile fluid.
I do not confine myself, in constructing my improved apparatus, to the employ-
ment of any special form of gas burner or valve, as it is obvious that I might
employ any suitable burner which will operate efficiently for the purposes of my
Invention.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
First. An apparatus for cooking, or digesting food, or for similar purposes, which
has a closed chamber so constructed and arranged in combination with a source of
heat that by its expansions and contractions due to variations of pressure therein,
the supply of heat to the contents of the said apparatus will be varied or controlled
for the purposes specified.
Second. In a cooking apparatus, the combination, with the receptacle for the
food, of a casing surrounding or enclosing the said receptacle so as to form a closed
chamber to contain liquid, substantially as, and for the purposes, set forth.
Third. A cooking vessel constructed with a yielding bottom, side, or diaphragm,
arranged in combination with a heater or burner for regulating the supply of heat
to the said vessel, substantially as set forth.
Fourth. The combination, with a vessel or receptacle for cooking or similar
purposes, of a gas-valve arranged to be operated by variations of pressure within
the said vessel or receptacle, or within one or more separate chambers, substantially
as, and for the purpose, set forth.

page_text: Fifth. The modification of my Invention wherein I employ a chamber partially
filled with alcohol or other volatile fluid, substantially as, and for the purpose,
specified.
Sixth. The improved apparatus consisting of the parts constructed and combined
substantially as described with reference to either of the forms or modifications
shewn in the accompanying Drawings and operating as, and for the purposes,
set forth.
Seventh. In, or for, a cooking apparatus, a Bunsen-burner made with a sliding
cap to which is fixed a spindle carrying a perforated piston or guide and serving as
a valve, substantially as, and for the purpose, set forth.
HASELTINE, LAKE & Co.,
For the Applicant.