U.S. patent number 3,807,194 [Application Number 05/296,785] was granted by the patent office on 1974-04-30 for thermodynamic container.
This patent grant is currently assigned to Royal Industries, Inc.. Invention is credited to Thomas G. Bond.
United States Patent |
3,807,194 |
Bond |
April 30, 1974 |
THERMODYNAMIC CONTAINER
Abstract
A thermodynamic container comprising a double walled, insulated,
plastic outer shell having a thermal energy storage material sealed
thereto. The thermal energy storage material coacts with a heat
exchanging plastic cup adapted to receive a product to be stored.
The thermal energy storage material is a pure compound formulated
for the specific temperature desired for the stored product, solid
or liquid. The container is capable of storing a product for a
preselected period with the product having the desired temperature
at the conclusion of the period.
Inventors: |
Bond; Thomas G. (Placentia,
CA) |
Assignee: |
Royal Industries, Inc.
(Pasadena, CA)
|
Family
ID: |
23143542 |
Appl.
No.: |
05/296,785 |
Filed: |
October 12, 1972 |
Current U.S.
Class: |
62/457.4; 62/430;
62/438; 62/371 |
Current CPC
Class: |
A47G
23/04 (20130101); F25D 3/06 (20130101); F25D
2303/0831 (20130101); F25D 2331/804 (20130101) |
Current International
Class: |
A47G
23/04 (20060101); A47G 23/00 (20060101); F25D
3/06 (20060101); F25D 3/00 (20060101); F25d
003/08 () |
Field of
Search: |
;62/430,438,457,371 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wye; William J.
Attorney, Agent or Firm: Christie, Parker & Hale
Claims
What is claimed is:
1. A temperature controlling container comprising a double walled
outer shell constructed of a plastic material having an internal
cavity, and
a thermal insulator arranged between the double walls of the shell,
a heat exchanging cup constructed of the same plastic material as
the shell having a layer of a thermal energy storage material
covering the sides and bottom of the cup, said thermal energy
storage material is a eutectic compound formulated for a
temperature selected relative to the desired temperature at which a
product carried in the cavity of the shell is to be stored, the cup
being mounted in the cavity of the outer shell with the storage
material in thermal contact with the inner wall of the shell, the
cup being secured to the inner wall of the shell to thereby seal
the energy storage material between the cup and said inner
wall.
2. A temperature controlling container as defined in claim 1
including
an insulative cover adapted to be secured to the outer shell and to
thermally enclose the outer shell and thereby the cup.
3. A temperature controlling container comprising
a double walled, insulative plastic outer shell having an internal
cavity,
a rigid thermal insulator filling the volume between the double
walls of the shell and being completely enclosed within the outer
shell,
a thin walled plastic heat exchanging cup mounted in the cavity of
the outer shell and being welded to the shell so as to be integral
therewith and defining a cavity between the inner wall of the shell
and the outer wall and bottom of the cup, and
a thermal energy storage material sealed in the cavity defined
between the cup and the inner wall of the shell in intimate thermal
contact with the walls defining the cavity to allow the cup to
function as a heat exchanger between the energy storage material
and a product stored in the cup to be maintained at a preselected
temperature, the heat flow through the cup being bidirectional.
4. A temperature controlling container as defined in claim 3
wherein the rigid insulator comprises a polyurethane system.
5. A temperature controlling container as defined in claim 4
wherein the insulator has a K factor of at least 0.15 and consists
of diphenylmethane diisocyanate.
6. A temperature controlling container as defined in claim 3
wherein the shell comprises a molded polypropylene.
7. A temperature controlling container as defined in claim 6
wherein the cup comprises a molded polypropylene.
8. An all-plastic temperature controlling storage container
comprising
a thin walled substantially U-shaped plastic container adapted to
receive a product, a solid or liquid, to be maintained at a
preselected temperature;
solid insulating plastic means having a substantially U-shaped
configuration for receiving the container therein and being sealed
thereto without any adhesives or artificial bonding agents, the
plastic for the container and the insulating means being
constructed of the same plastic material to allow it to be
sealed,
the insulating means and the container being constructed and
defined for providing a sealed cavity between the container and the
insulating means, and
a thermal energy storage material stored in the thus defined sealed
cavity and in intimate contact with the walls defining the sealed
cavity, the energy storage material comprising a eutectic material
for maintaining a product stored in the thin walled container at a
preselected temperature, the energy storage material being adapted
to store thermal energy in response to the difference in
temperature of a product stored in the container and the material
as a result of the exchange of heat through the thin walled
container whereby the thermal energy stored by the material is
released to the product when the product exceeds the preselected
temperature, the thermal energy material exhibiting a complete
fusion of crystallization cycle for the exercise of its full energy
storage capabilities.
9. An all-plastic temperature controlling storage container as
defined in claim 8 including a solid insulative cover for securing
and sealing said solid insulating means and any product stored
therein.
10. An all-plastic temperature controlling storage container as
defined in claim 8 wherein the thin walled container has its inner
wall fluted for increasing the heat transfer area of the container
and providing additional structural strength.
11. An all-plastic temperature controlling storage container as
defined in claim 8 wherein thermal energy storage material is a
pure euctectic compound deposited on and carried by said U-shaped
container.
12. A temperature controlling container comprising
a substantially U-shaped, solid, relatively thick insulative
housing,
a heat exchanging cup having a thin layer of thermal energy storage
eutectic compound deposited on the outer sides and bottom of the
cup by inducing crystallization of the eutectic onto the sides and
bottom of the cup, the cup being heat sealed to said solid
insulating housing to thereby seal the thermal energy layer
therebetween whereby leakage of the heat storage material during
normal operation is prevented.
13. A temperature controlling container as defined in claim 12
wherein the eutectic compound is deposited on the cup by suspending
the cup in a molten solution of the compound to induce
crystallization of the eutectic onto the cup.
14. A temperature controlling container as defined in claim 12
wherein the cup has serrated walls and the housing is provided with
a screw-type lid for providing a liquid-tight seal for the housing.
Description
This invention relates to a thermodynamic container and more
particularly to containers employing heat storage materials for
maintaining products stored in the containers at a preselected
temperature in accordance with the desired temperature for the use
or consumption of the selected stored product.
PRIOR ART
At the present time, there are various types of containers that are
known in the prior art, some of which are commercially available.
These prior art containers include insulated containers made of
plastic or the like, vacuum or thermos bottles and cups and
containers employing heat storage materials or eutectic compounds.
The insulated containers that are commercially available are in the
form of small insulated cups which consist basically of a plastic
shell which may be constructed of a polypropylene material. Some of
these cups include a low density foam plastic insulation in
addition to the basic plastic shell. It is also known that some of
the cups that are commercially available and constructed as
mentioned hereinabove, may include a thin wafer of water in the lid
of the cup which may be frozen to provide some cold storage
capabilities around 32.degree. F. These cups usually have their
lids insulated with cork rather than a foam plastic. In general,
the construction of this type of prior art cup is in terms of snap
fitting the parts together or spin welded pieces. Due to the lack
of the incorporation of a thermal energy storage material in these
cups, the insulating properties and thereby the use thereof is
limited to a relatively short product storage period.
A well-known type of thermodynamic container that has been used
extensively is the vacuum bottle carrier which is also known as a
thermos bottle. A true vacuum bottle carrier has superior heat
retention characteristics relative to any presently known
thermodynamic container. A true vacuum bottle, however, is a
relatively expensive container. Inexpensive vacuum bottles have
been produced and are commercially available that sell for
approximately $2.50. The less expensive vacuum bottles that are
commercially available have been found to be disadvantageous since
they are highly subject to damage from being dropped or thrown. The
damage prone characteristics of these inexpensive vacuum or thermos
bottles results from the fragile nature of the glass bottle that is
employed in combination with an inadequate suspension system. The
suspension and cushioning system of such a vacuum bottle is not
adequate to sustain the mechanical shocks and they have been found
to have a relatively short life expectancy, particularly when used
by school children. As to the true vacuum bottle (a more expensive
type) from the standpoint of maintaining hot foods at desired
temperatures, the heat retention characteristics of such a vacuum
bottle are so good that it may produce stored foods that are too
hot to be consumed and must be cooled before eaten. Stated
differently, the desired eating temperature for such hot foods is
not realized through the use of a true vacuum bottle whereby the
user may be burned from eating hot soup or similar hot foods.
Other thermodynamic containers employ eutectic materials for their
particular function. One such thermodynamic container is described
in U. S. Pat. No. 3,603,106. In this prior art type of container, a
separate heat exchanger element adhesively bonded to the shell is
employed. The purpose of such eutectic cups is generally to cool
products to a specific temperature. The products used with such
eutectic containers are coffee, tea and the like. Accordingly,
there is a present need in the market place for an inexpensive and
effective thermodynamic container that has energy storage
properties which allows a product to be stored for a preselected
period so that it will be at the correct temperature when it is
desired to use the product or the product is to be consumed.
Preferably, the thermodynamic container should be less expensive
than the true vacuum bottle, be reuseable a multiplicity of times
and should be constructed so as to have a relatively long life,
including when used by children.
DISCLOSURE OF THE INVENTION
The present invention provides an improved, relatively inexpensive,
reusable thermodynamic container for maintaining a product to be
stored in the container at a preselected temperature by virtue of
the inclusion of a thermal energy storage material in an improved
combination of elements comprising the container. The cost of the
container of the present invention is less than the inexpensive
vacuum bottle referred to hereinabove. In a container of the
present invention, the product stored within the container can be
maintained at a specific temperature best suited to the product
requirements. To this end, for example, soup can be kept at
130.degree. F for 5 hours at a normal schoolroom ambient
temperature and be ready to eat at noontime. In the same fashion,
gelatins and puddings can be kept at 40.degree. F for a similar
period. Ice cream can be kept frozen for 4 to 5 hours by using a
0.degree. F energy storage material in the container of the present
invention. This type of temperature storage capability is greatly
superior to existing insulating containers as the result of a
combination of eutectic heat exchangers and the improved insulation
system employed in the thermodynamic container of the present
invention. For example, comparison tests performed with the
existing commercially available insulated cups show that the
identical product load of hot food is 35.degree. F cooler at the
end of the 5 hours in an insulated cup without an energy storage
material than the same product load in the thermodynamic container
of the present invention. During this test, the product temperature
at the end of the 5 hours was 90.degree. in the insulated cup and
125.degree. in the container of the present invention. It should
also be noted that some products cannot be carried in the existing
insulated cups. For example, ice cream will melt and gelatin will
lose its form when stored in such prior art containers. Similarly,
prepared food which should be hot when eaten falls substantially
below body temperature and chilled products, such as soups, become
warm in the existing insulated containers.
From a structural standpoint, the present invention provides a
temperature controlling container comprising a double walled outer
shell having an internal product storage cavity to receive and
store the product which is to be temperature controlled. The
temperature control is in terms of both maintaining the product at
a low temperature or a high temperature relative to the ambient
temperature in which the container is employed. A thermal insulator
is arranged between the double walls of the shell. In combination
with the outer shell, a heat exchange cup having a layer of thermal
energy storage material covering the sides and bottom of the cup is
employed. The cup is mounted in the cavity of the outer shell with
the storage material in intimate contact with the inner walls of
the shell. The cup is secured to the inner wall of the shell to
thereby seal the energy storage material between the cup and the
inner wall. An insulative closure can be adapted to be secured to
the outer shell and to thermally enclose the outer shell and
thereby the heat exchanging cup.
These and other features of the present invention may be more fully
appreciated when considered in the light of the following
specification and drawings, in which:
FIG. 1 is an exploded view of the thermodynamic container of the
present invention illustrating a sealed food container to be stored
in the temperature controlling container embodying the present
invention; and
FIG. 2 is a cross sectional view of the thermodynamic container of
FIG. 1 illustrating the closure secured thereto.
Now referring to the drawings, the construction of the
thermodynamic container 10 of the present invention will be
described in detail. It should be noted at the outset that the
container is particularly constructed and defined to accept a
commercially available food container in the form of a sealed tin
can and the invention will be described for such a use. However, it
should be understood that the container 10 can be used for the
storage of liquids or foods that come into direct contact with the
container without any direct chemical or toxicological effects on
the stored product. The container 10 comprises a temperature
controlling carrier 11 having an internal product storage cavity 12
for accepting a sealed container 13 that has been temperature
conditioned to the desired temperature either above or below the
ambient temperature such as the tin can 13 illustrated in FIG. 1.
The temperature controlling carrier 11 may include a closure 14
adapted to be secured to the carrrier 11 for sealing the food
container 13 within the product storage cavity 12.
Specifically referring to FIG. 2, the details of the internal
construction of the container 10 will become apparent. The
temperature controlling carrier 11 comprises an open ended, double
walled outer shell that may be constructed of plastic material
preferably of a molded polypropylene. The entire double walled
shell is produced as a unitary structure to receive a thermal
insulating material between the volume defined by the double walls
11.sup.o and 11.sup.i. This volume of material is filled with a
rigid thermal insulator 15, preferably a rigid urethane material to
completely fill up the space between the walls 11.sup.o and
11.sup.i. The thermal insulating material that has been found to
have the necessary advantageous insulating properties is a rigid
polyurethane system that has an insulation K factor of at least
0.15 and consists of diphenylmethane diisocyanate (MDI). It has
been found that due to the other parameters and materials used for
the container 10, no other material commercially available provides
a comparable insulative K factor or insulating value for the
purposes of the present invention. The chemical properties of such
rigid polyurethane systems are described in standard commercial
literature. Such polyurethane systems will be purchased from either
Urethane Systems, Inc. of 416 W. El Segundo Blvd., Gardena, Calif,
or from Polymir Industries of 520 W. Walnut, Orange, Calif., 92668
as MDI-CFD-125 -- 2 lbs. per cubic foot. The open-ended bottom
section of the double walled outer shell 11 may be enclosed after
the thermal insulator 15 is placed between the walls of the shell
11 by means of a base retaining disc 16, that may be sonic welded
to the outer shell 11, thus forming a completely sealed unit. For
this purpose the base disc 16 may comprise a thin molded
polypropylene disc.
The double walled outer shell, or carrier 11, is of a substantially
U-shaped configuration and thereby defines an internal product
storage cavity 12 between the inner walls 11.sup.i. Within the
inner cavity there is positioned a heat exchanging cup 17 that is
constructed of a plastic material and preferably the same plastic
material that the outer shell 11 is constructed of. Specifically,
the heat exchanging cup 17 is constructed of a molded
polypropylene. The heat exchanging cup 17 is welded or heat sealed
at its upper edges to the inner wall 11.sup.i of the double walled
shell 11, as indicated in FIG. 2 by the reference number 18. The
inner wall of the heat exchanging cup 17 may be defined as a fluted
or corrugated structure to increase the heat transfer area afforded
by the cup 17 and also provide added structural strength for the
container. The entire inner wall of the cup 17 may be fluted as
indicated by the reference number 17.sup.f.
It should be noted at this point that because the cup 17 and the
shell 11 are constructed of the same plastic material and are
welded or heat sealed together without resorting to adhesives or
artificial connectors, the container 10 can be reused extensively
and by washing after use, including being subjected to the extreme
temperatures prevailing in a home dishwasher. With the two basic
elements of the container 10 constructed of the same material, the
coefficients of thermal expansion and contraction of these elements
is identical so that the container 10 can be subjected to
temperature extremes without the fear of harm to the container due
to separation of the various parts such as could occur to a
thermodynamic container comprising different materials having
greatly different thermal characteristics. For example, the use of
a plastic material in combination with aluminum material exhibits
coefficients of thermal expansion which are significantly different
so that the use of these materials over a long period of time could
create wear and leakage problems at the joints of the two
materials.
The remaining element of the temperature controlling carrier 11 is
the thermal energy storage material 19 arranged in the sealed
cavity defined between the outer wall and bottom of the cup 17 and
the adjacent walls of the inner wall 11.sup.1 of the double walled
shell 11. The thermal energy storage material 10, when arranged in
this fashion, is sealed around the sides and bottom of the heat
exchanging cup 17 by the heat seal 18, thereby eliminating any
leakage into the product storage cavity 12 and the product stored
therein. The thermal energy storage material 19 is selected to
maintain the product stored within the cup 17 at a preselected
temperature. For this purpose, the thermal energy storage material
19 is a eutectic compound that is specifically formulated for the
desired temperature at which the product carried by the cup 17 is
to be stored. A wide range of specific temperatures can be
maintained by the container 10 through the selection of the
particular eutectic materials. For example, temperatures such as
150.degree., 140.degree., 130.degree., 120.degree., 65.degree.,
40.degree., 27.degree., 12.degree. and 0.degree. may be provided.
These eutectic materials are well known in the art and have
different heats of fusion depending upon their formulations to
provide a desired temperature. A 150.degree. F temperature may be
maintained for a stored product by using a thermal energy storage
material described in the Telkes/U.S. Pat. No. 2,936,741. If a
97.degree. F environment is to be provided for the material, the
material described in the Telkes/U.S. Pat. No. 2,677,367 may be
employed. For transportation and storage of ice cream and frozen
ices wherein a 12.degree. F environment must be provided, a
material composed of potassium chloride and water may be employed.
Other temperatures may be provided through the formulation of
various other materials such as various other eutectic compounds in
accordance with the desired temperature. Other materials for the
purposes of the present invention are described in the Telkes/U.S.
Pat. Nos. 2,677,664 and 2,989,856. The compounds for the thermal
energy storage materials described in each of the aforementioned
Telkes U. S. patents are incorporated herein by reference.
It is preferable to employ a thermal energy storage material that
is non-toxic or non-corrosive, particularly when foods are being
stored, since leakage of the material into a food product would
drastically alter the taste of the food and spoil it for human
consumption. The sealing of the thermal energy storage material
within the carrier 11 renders the container 10 less prone to
leakage and escape into the product storage cavity 12.
It should be noted that the use of an integral plastic heat
exchanging cup 17 permits the container 10 to use the full range of
eutectic materials from hot to very cold materials. Many known
eutectic materials, particularly those providing cold temperatures,
are corrosive to heat exchanging elements such as aluminum so that
the all-plastic construction afforded by the present invention
obviates these inherent problems. Due to the nature of the heat
exchanging structure, the plastics used and the deposition
techniques for the eutectic materials employed comprising pure
compounds that do not require heat transfer augmentation such as
aluminum powder or copper mesh, all of the space available between
the inner walls 11.sup.i and the heat exchanging cup 17 is
available to carry and store the thermal energy storage material 19
and none of the space is devoted to heat transfer augmentation
materials. These parameters permit a complete phase change of the
thermal energy storage to occur in the proper functioning of the
container 10. Therefore, the full phase change energy storage
capabilities of the material 19 is employed. Failure of the
material 19 to experience a complete transition will result in
significantly reduced performance because the full energy storage
capability of the material is not employed.
At this point it will be well to examine the method of
incorporating the thermal energy storage material 19 into the
container 10. For this purpose it has been found to be most
advantageous to deposit the thermal energy storage material 19 over
the outside walls and the bottom of the heat exchanging cup 17 by
inducing crystallization. This is accomplished by placing the heat
exchanging cup 17 into a molten solution of the selected eutectic
compound. The molten solution of the eutectic compound should be
maintained at a temperature of 20.degree. F above the operating
temperature of the eutectic compound. Under these conditions, the
cup 17 is suspended into this heated solution and cooling is
allowed to occur to induce crystallization of the eutectic material
to the sides and bottom of the cup. The rate of crystallization
varies with each material and is determinable. It should be noted
that when the heat exchanging cup 17 is prepared in this fashion,
the thermal energy storage material is deposited thereon in an
amount and thickness that is carefully regulated to insure that a
uniform layer of material is deposited to insure the even and rapid
transfer of heat during the conditioning phase of the thermal
energy storage material and a uniform transfer of heat to the
stored product when the container 10 is in use. The heat exchanging
cup 17, carrying the deposited thermal energy storage material 19,
may then be placed into the internal cavity provided by the double
walled shell 11 and then welded to the shell such as by heat
sealing or the like. When the thermal energy storage material 19 is
completely sealed in this fashion, no opportunity is afforded for
escape of the thermal energy storage material for contamination of
the product stored within the cup 17. Also, it will be noted that
the heat exchanging cup 17 becomes an integral part of the cup
shell 11 without resorting to adhesives or artificial
connectors.
A very important aspect of the present invention appears to be the
critical parameters that are necessary for the proper operation of
the container 10. The walls of the cup 17 must be extremely thin to
permit rapid conditioning of the thermal energy source material
19.
To this end, in one practical embodiment of the invention the walls
of the cup 17 are defined on the order of 0.035 inch. It also
appears that the deposition of the energy storage material 19 onto
the wall of the heat exchanging cup 17 must be induced by
crystallization and also be extremely thin, on the order of
one-eighth of an inch. In conjunction with these critical
conditions, it has been found that because of the very thin wall of
the cup 17 and the relatively small amount of energy that may be
stored in the thermal energy storage material 19, that only the
rigid polyurethane system affords the necessary insulating
properties for proper operation. As a result of the special
attention to the aforementioned parameters, the thin layer of
energy storage material 19 is readily melted or solidified by the
conditioning process and allows complete phase change of the
thermal energy material 19 to take place during the proper
operation of the container 10. This allows the full energy
capabilities of the storage materials to be employed. In
conformance with the aforementioned parameters, to assure maximum
performance of the container 10 of the present invention, the
internal cavity for the heat exchanging cup 17 should provide a
close physical contact between the container 13 and the adjacent
wall of the cup. A close physical fit or contact with the walls of
the cup avoids heat losses that would occur if a space is allowed
between the container 13 and the cup 17.
The container 11, constructed in this fashion, may also include a
ring element 20 mounted to the inner wall 11.sup.i above the outer
periphery of the cup 17 to further secure the cup in position and
enclose the joint 18 between the cup 17 and the wall 11.sup.i. The
retaining ring 20 may also be constructed of a plastic material and
preferably a molded polyethylene.
The closure or lid 14 for the container 10 may be constructed and
defined to secure and seal the interior of the double walled shell
11 carrying the cup 17. For this purpose, the closure 14 may be of
a screw type to be threaded onto the outer wall 11.sup.i of the
carrier 11 adjacent its top as best illustrated in FIG. 2. To this
end, the inner wall 14.sup.i of the closure is defined to be
threaded onto the carrier 11 as illustrated. The closure 14 as
constructed and defined is made of the same plastic material as the
shell 11 and the cup 17, namely, a molded polypropylene. The
closure 14 is constructed with a dependent portion having a thermal
insulator stored therein. The thermal insulator is identified by
the reference numeral 21 and comprises a rigid urethane material
such as employed for the double walled shell 11. As is evident from
examining FIG. 2, the thermal insulator 21 is enclosed by means of
an insert that is press fit into the closure 14. The insert is also
constructed of a plastic material preferably of a molded
polypropylene, the same as the closure proper.
With the above construction in mind, the principles of operation of
the container 10 may now be examined. The container 10 operates by
taking advantage of the heat of fusion or heat of crystallization
of the thermal energy storage material 19 to provide an energy
source to maintain the product, food or liquid, stored in the cup
17 at a preselected temperature. The energy available from fusion
or crystallization is conserved or directed by the insulator 15 in
which the cup 17 is contained. By this method, a preselected
temperature is established within the product stored in the cup 17
and may be maintained for a specified period of time depending upon
the ambient temperature in which the container 10 is employed. It
will be assumed that the ambient temperature is in the range of
75.degree. - 80.degree. F.
The energy necessary to cause the phase change phenomenon to occur
is supplied from at least two sources. The can 13, or other
container of food, which is placed in the cup 17 must be above the
final desired temperature, if the cup is to keep the food warm.
Similarly, the product placed in the cup 17 must be below the
desired temperature if the cup is to be used to keep the product
chilled. Therefore, the primary energy source to activate the
thermal energy storage material 19 is provided by the product
stored within the cup 17. The second source of energy for
activating the thermal energy storage material 19 is supplied from
an external source. This source of energy can be supplied by
placing the container 10 in the refrigerator for a preseribed
period of time prior to its intended use, if it desired to keep the
product within the container chilled. This would freeze or
crystalize the thermal energy storage material 19 and provide the
necessary cold energy required to keep the food in a chilled
condition. Alternatively, in the event the container is used to
keep a product warm, hot water at least 20.degree. F over the
desired operating temperature should be circulated through the
inside of the cup for at least five minutes to charge the thermal
energy storage material 19.
With the above considerations in mind, the thermo dynamic container
10 will be described as it can be conditioned for the purposes of
storing a sealed can 13 having a food product stored therein. For
this purpose, it is desired to maintain the container 10 in an
ambient temperature of 75.degree. F and to keep a sealed can 13 of
a food product at a temperature of at least 125.degree. F for 5
hours. To use the container 10 for such an application, it is
necessary to bring the contents of the can 13 to 175.degree. F by
immersing the sealed can into boiling water for 15 minutes. While
the can 13 is heating, the container 10 is conditioned by pouring
boiling water into the container 10, loosely replacing the closure
14 and allowing the hot water to stand in the container for 5
minutes. After the can 13 has been heated to the desired
temperature, the container 10 is emptied of the hot water. The
heated can 13 is inserted into the cup 17 and the closure 14 is
secured to the carrier 11. The can 13 remains sealed at all times
until it is opened for consumption. Under these conditions it has
been found that the food stored within the tin can 13 is at the
correct and desired temperature for consumption at the end of 5
hours. It has been found that a sealed can 13 of chili beans and
franks has been maintained at a temperature of 129.2.degree. F, a
sealed can of spaghetti has been maintained at a temperature of
130.0.degree. F. and a sealed can of beef stew has been maintained
at a temperature of 129.2.degree. F. Alternatively, the container
10 may be used to maintain a product in a chilled condition by
following the aforementioned steps. In this respect, the product is
chilled below the desired temperature and the container cooled by
placing it in a refrigerator to solidify the material 19 prior to
insertion and storing the chilled product.
* * * * *