Note: Descriptions are shown in the official language in which they were submitted.
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SELF-CONTAINED SILICONE-GEL INSULATED CONTAINER
FIELD OF THE INVENTION
The present invention concerns insulated containers, more particularly
self-contained insulated containers for maintaining an item at a predetermined
temperature.
BACKGROUND OF THE INVENTION
Insulated containers for storing perishable items such as foodstuff and
medical specimens at predetermined temperatures are well known and widely
used.
Typically, the containers include an insulating wall that surrounds the item
and an
insulated lid, vvhich fits in a sealing arrangement onto the container to
maintain an
internal container temperature. The insulating wall may be constructed of
solid foam like
insulator such as polymeric foam or the wall may contain an evacuated airspace
such as
that found in Thermos flasks. Also, for keeping foodstuff chilled in an ice
chest, for
example, for use on a picnic, ice packs are available which must first be
frozen before
adding to the insulated container along with the foodstuff. This relatively
simple method
does, however, suffer from a number of significant disadvantages. PJlost of
the insulating
materials used serve only as thermal insulators and do not have any
significant heat
capacity. As such, they are inefficient at maintaining the internal
temperature of the
container for a prolonged period of time. Furthermore, some containers can
either
accumulate or retain heat, but are not transportable a:~ such. These usually
fit within a
larger container, or include their own power system to control the temperature
therein.
Also, for applications such as a freezer or a kitchen stove or the like, the
insulating walls
do not accumulate or retain the heat to minimize the heat transfer with the
environment.
Thus, there is a need for an insulator for use with a container which is
self-contained and which insulates pre heated or pre-coo4ed items for an
extended
period of time.
SUMMARY OF THE INVENTION
The inventor has unexpectedly discovered that an aqueous mixture of
silicone-gel material, when sandwiched between two sealed walls, forms an
insulator,
which if it surrounds an item having a predetermined temperature, rryaintains
the item at
the predetermined temperature for a significant period of time (up to many
hours for a
cold item). Advantageously, a container that includes the insulator has
significantly
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improved insulating properties and when pre-cooled or pre-heated, maintains an
internal
storage temperature for an extended period of time. foodstuff that is pre-
heated or pre-
cooled can be stored for extended periods in the container and the container
will
maintain the internal temperature for the extended period. Other applications
include,
but are not limited to, the use of the container for transporting human organs
for
transplant or for transporting other perishable medical specimens. ~esirably,
the
material can be used to increase the energy efficiency of appliances such as
refrigerators or stoves, ovens, freezers and water tanks, by insulating the
outer shell with
the material. One may also contemplate the use of this material irr the
building trade to
provide effective insulation in the walls' cavities. Advantageously, the
silicone-gel
mixture is an inert, non-toxic, biodegradable, and non-adhesive aqueous
silicone-gel that
also has heat/coid accumulating properties otherwise known as Phase Change
Material
(PCM), which minimizes heat exchange from the container to the surrounding
environment.
According to a first aspect of the present invention, there is provided a
self-contained insulated container for maintaining an item at a predetermined
temperature, the container having an inner sidewall and an outer sidewall, the
sidewalk
being spaced apart from each other and closed off to define an insulating
chamber
therebetween, the container comprises:
- a storage area for receiving the item therein, the storage area being
defined by
the inner sidewall, the storage area being at a first storage temperature;
- the insulating chamber being substantially filled with a first in sulating
material, the
first insulating material being an aqueous silicone-gel mixture, the first
insulating
material being at a first insulating temperature, the storage area attaining a
second storage temperature after the item is placed therein, the first
insulating
material maintaining the second storage temperature and the item at the
predetermined temperature for a storage period.
In one embodiment, the first insulating material is located centrally in the
insulating chamber, the first insulating material having first and second air
spaces on
each side of the first insulating material, the first air space being adjacent
the inner
sidewall and second air space being adjacent the outer sidewall.
Typically, first and second sectional walls are located between the first
insulating material and the first and second air spaces.
Typically, a second insulating material is located on either side of the first
and second air spaces, the second insulating material being respectively
adjacent the
inner sidewall and the outer sidewall.
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In one embodiment, the container is a generally closable container and
defines side panels, a floor panel, and an openable lid panel, at least one of
the side,
floor and lid panels including the insulating chamber.
According to a second aspect of the present invention, there is provided
an insulator liner for use with a container having an inner sidewall and an
outer sidewalf,
the sidewalls being closed off and defining an insulating chamber
therebetween, the
container being for storing a pre-heated or a pre-cooled item, the insulator
liner
comprises:
an insulating material, the insulating material being made from an aqueous
silicone-gel mixture, the material substantially filling the insulating
chamber, the
insulating material being at a first insulating temperature; and
- a storage area defined by the inner sidewall being at a first storage
temperature,
the storage area attaining a second storage temperature after the item is
placed
therein, the insulating material maintaining the second storage temperature
and
the item at a pre-cooled or a pre-heated temperature for a storage period.
According to a third aspect of the present invention, there is provided a
method of maintaining the second storage temperature and the predetermined
temperature of a pre-cooled item for an extended storage period in the self-
contained
insulated container as described hereinabove, the metl-iod comprises:
- insulating the pre-cooled item in the container, the container being pre-
cooled to
attain the first insulating temperature and the first storage temperature, the
storage area attaining the second storage temperature after the pre-cooled
item
is placed therein, sa as to maintain, for the storage period, the second
storage
temperature and the pre-cooled item at the pre-determined temperature.
Other objects and advantages of the present invention wilt become
apparent from a careful reading of the detailed description provided herein,
with
appropriate reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE ~RAWINGS
In the annexed drawings, like reference characters indicate Pike elements
throughout.
Figure 1 is a perspective view, showing an embodiment of a food
container unit including a insulator liner in accordance with the present
invention;
Figure 1 a is a partial section view taken along line 1 a-1 a of Fig. 1;
Figure 2 is a perspective partial cutaway view of anoi:her embodiment of
the insulator liner used in a freezer in accordance with the present
invention;
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Figure 3 is a perspective partial cutaway view of another embodiment of
the insulator liner used with a stove in accordance with the present
invention;
Figures 4 through 16 are partial section views, showing different panel
arrangements including the insulator liner;
Figure 17 is a graphical representation showing the differences between
an external temperature (open diamonds), the internal (or storage) temperature
for a pre-
cooled silicone-gel insulated container with an insulated lid (solid
diamonds), the internal
temperature for a pre-cooled conventionally insulated container having a pre-
cooled floor
covering icepack therein with a non-insulated lid (stars), the internal
temperature for a
pre-cooled conventionally insulated container having a pre-cooled block-shaped
icepack
therein with a non-insulated lid (solid triangles), and the internaV
temperature with a
plurality of items, including 1 liter of water at room temperature, placed
therein with an
insulated lid (dotted line); and
Figure 18 is a graphical representation showing the differences between
an external temperature (open diamonds), the internal (or storage) temperature
for a pre-
heated conventionally insulated container having a pre-heated item therein
with a non-
insulated lid (solid squares) and the internal temperature for a pre-heated
silicone-gel
insulated container having a pre-heated item therein with an insulated lid
(solid
diamonds).
DETAILED DESCRiPTfON OF THE PREFERRED EMBODIMENTS
With reference to the annexed drawings the preferred embodiments of the
present invention will be herein described for indicative purposes and by no
means as of
limitation.
Referring now to Figs. 1 through 3, there is illustrated an embodiment of
an insulator (or insulator liner) 40 in accordance with the present invention
when used
with a food or item storage unit, for example, a lunch box 20, a freezer 20a
and a stove
20b, which are illustrated in an open configuration for convenient
illustration.
As shown more specifically in Fig. 1, the food storage unit 20 is
rectangular in shape and includes four side panels 22, a base plate 2.4 and a
covering lid
26 for access to its contents (not shown) in open configuration. The covering
lid 26 may
be optionally insulated with material known to those skilled in the an. The
side panels
22, the base plate 24 and the lid 2C typically include an exterior sidewall 28
and an
interior sidewall 30. As best illustrated in Fig. 1a, the sidewalls 28 and 30
are spaced
apart and are sealed at the upper end 31 and form a chamber 33. The chamber 33
may
be partially or completely filled with the insulator 40.
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The insulator 40 consists of a first insulating material that includes an
aqueous silicone-gel mixture. Typically, the aqueous silicone-gel mixture
consists of not
less than 0.1 % silicone-gel by volume and not more than 10% silicone-gel by
volume.
More typically, the aqueous silicone-gel mixture consists of from 0.5%
silicone-gel by
volume to 5% silicone-gel by volume. Most typically, the aqueous silicone-gel
mixture
consists of 2% silicone-gel by volume.
Referring now to Figs. 4 through 16, a variety of insulating components
32, 34, and 40, which include the insulator liner 40, an airlgas space 32, and
second
insulation material 34 known to those skilled in the art, for example,
polyurethane,
expanded polystyrene, polyisocyanurate, fiberglass and the Pike. These
components 32,
34, 40 are separated by sectional walls 36, typically covered with reflective
coating(s),
and their relative arrangement may vary according to the specific needs of the
user. The
advantages provided by the insulator liner 40 over conventional forms of
insulation
material 34 is that it is non-toxic, non-flammable, biodegradable and non-
adhesive.
Additionally, it has properties that can absorb and retain latent heat and can
be either
pre-heated or pre-cooled depending on its intended use.
Alternatives
Different arrangements of the insulator liner 40 with other components 32,
34, 36 are specifically depicted in Figs. 4 through 16; in which the
arrangement from the
exterior wall 28 to the interior wall 30 typically, and in sequence, include:
- the exterior wall 28, the insulator diner 40 and the interior wall 30 (Fig.
4);
- the exterior wall 28, an air/gas space 32, a sectional wall 36, the
insulator liner
40 and the interior wall 30 (Fig. 5);
- the exterior wall 28, an air/gas space 32, a sectional wall 36, the
insulator liner
40, a sectional wall 36, an air/gas space 32 and the interior wail 30 (Fig.
6);
- the exterior wall 28, insulation 34, a sectional wall 36, the insulator
liner 40, a
sectional wall 36, an airlgas space 32 and the interior w<~II 30 (Fig. 7);
the exterior wall 28, insulation 34, a sectional wall 36, the insulator liner
40 and
the interior wall 30 (Fig. 8);
- the exterior wall 28, insulation 34, a sectional wall 36, an air/gas space
32, a
sectional wall 36, the insulator finer 40 and the interior wail 30 (Fig. 9);
- the exterior wall 28, an airlgas space 32, a sectional wall 36, insulation
34, a
sectional wall 36, an airlgas space 32, a sectional wall 36, the insulator
liner 40 and the
interior wall 30 (Fig. 10);
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- the exterior wall 28, an air/gas space 32, a sectional wall 36, insulation
34, a
sectional wall 36, the insulator liner 40 and the interior wall 30 (Fig. 11 );
- the exterior wall 28, an air/gas space 32, a sectional wall 36, horizontally
alternating layers of the insulator liner 40 and insulation 34 separated by
horizontal
sectional walls 36' and the interior wall 30 (Fig. 12);
- the exterior wall 28, an air/gas space 32, a sectional wall 36, horizontally
alternating layers of the insulator liner 40 and insulation 34 separated by
horizontal
sectional walls 36', a sectional wall 36, an airlgas space 32 and the interior
wall 30
(Fig. 13);
- the exterior wall 28, insulation 34, a sectional wall 36, an airlgas space
32, a
sectional wall 36, the insulator liner 40, a sectional wall 36, an airlgas
space 32 and the
interior wall 30 (Fig. 14);
- the exterior wall 28, insulation 34, a sectional wall 36, an airAgas space
32 with
crenellated application of the insulator liner 40 separated by substantially
horizontal
sectional walls 36' and the interior wall 30 (Fig. 15); and
the exterior wall 28, insulation 34, a sectional wall 36, an air/gas space 32,
a
sectional wall 36, the insulator finer 40, a sectional wall 36, an airlgas
space 32, a
sectional wall 36, insulation 34 and the interior wall 30 (Fig. 16).
Combinations of the above listed types of arrangement could be used in
alternation and/or in juxtaposition within a single panel, depending of the
specific needs
andlor requirements for the container 20, 20a, 20b. One skilled in the art
will recognize
that due to manufacturing andlor design constraints, such as the use of seals
and
ornamentation, the side panels 22, the base plate 24 and the lid 26 may not be
completely covered by the insulator liner 40.
Further applications of the insulator liner 40 could extend to commercial,
industrial and residential building complexes in a format yet to be
determined; such as
rolls, pre-sized flat-like or molded panels or the like, to cover room walls,
ceiling andlor
floors. Additionally, the insulator liner 40 could eventually replace existing
insulating
systems on a variety of appliances such as hot water tanks, drink liquid
containers,
medical-type containers, and the like.
Operation
As illustrated in Fig. 1, and more specifically Figs. 17 and 18, a user can
use the lunch box 20 in one of two ways with a food item (not shown) at a
predetermined
temperature. if a cold food item is to be maintained at a cool second storage
temperature, the container 20 is first placed in a freezer for a pre-
determined amount of
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time, such as up to 48 hours, and typically about 12 hours (overnight). After
this cooling
period, a first storage temperature in the storage area 35 is attained.
Typically, the first
storage temperature is -25°C or more and 10°C or less. More
typically, the first storage
temperature is -10°C or more and 5°C or less. During the cooling
period, the insulating
material reaches an insulating temperature, which is typically -25°C or
more and 10°C or
less. More typically, the insulating temperature is -25°C or more and
5°C or less. When
the generally cold food item at the predetermined temperature, typically at
0°C or more
and 5°C or less, is placed in the storage area 35, the storage area 35
attains the second
storage temperature. Typically, the second storage temperature is -5°C
or more and
10°C or less. More typically, the second storage temperature is
0°C or more and 5°C or
less. As is illustrated in Fig. 17, the insulator material 40 insulates the
storage area 35
and the food item against excessive warming and maintains the storage area at
the
second storage temperature for a storage period of up to 12 hours, as opposed
to the
relatively rapid warm-up obtained using a pre-cooled conventionally insulated
lunch box
with an icepack therein. This is particularly useful for applications in which
the item in
the storage area 35 is extremely sensitive to temperatuares above 5°C,
such as medical
specimens. It would be obvious to one skilled in the art that the pre-
determined
temperature of the item could be around room temperature without departing
from the
scope of the present invention.
As is illustrated in Fig. 18, if a hot item, for exarreple soup, is to be
30
maintained above an external temperature (typically room temperature of up to
25°C) of
the container 20 external sidewall 28 for an extended period of time, the item
is first
heated to the predetermined temperature, typically up to about 70°C and
then placed in
the storage area 35 of the pre-heated container 20. Typically, the container
20 is pre-
heated, such as using a conventional microwave oven or the like, and the
insulating
material 40 reaches the insulating temperature, which is typically up to about
70°C, and
the first storage temperature typically being up to about 70°C. ~ver
time, the storage
area 35 attains the second storage temperature. Typically, the second storage
temperature is 30°C or more and 70°C or less. The results
illustrated in Fig. 18 show
that for the pre-heated item, there is a more gradual cooling trend of the
internal
temperature when the container 20 of the present invs:ntion is used compared
to the
cooling trend of a pre-heated conventionally insulated container is used. Une
skilled in
the art will understand that increasing the Thickness of the first insulating
material will
increase the storage period to beyond the approximately 4 hours as illustrated
in Fig. 18.
Although the present self-contained silicone-gel insulated container with
its insulator liner has been described with a certain degree of particularity,
it is to be
CA 02444849 2003-10-14
understood that the disclosure has been made by way of example only and that
present
invention is not limited to the features of the embodiments described and
illustrated
herein, but includes ail variations and modifications within the scope of the
present
invention as hereinafter claimed.
