Note: Descriptions are shown in the official language in which they were submitted.
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CONTAINER WITH INTEGRAL MODULE FOR HEATING OR
COOLING THE CONTENTS
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates generally to containers that include an internal
module that adds heat to or removes heat from a material, such as a food,
beverage,
medicine, or the like, in the surrounding container.
Description of the Related Art
Containers may have integral modules for warming materials in the container,
such as sake, coffee, or soup. Examples of such self-heating containers are
disclosed
in U.S. Pat. Nos. 5,461,867; 5,626,022; and 6,351,953 issued to Scudder et al.
All
patents, patent applications and other publications referenced in this
application are
hereby incorporated by reference herein in their entirety. Such containers
typically
include an outer can or body, in which the food or beverage is sealed, and an
inner
can or thermic module that contains two chemical reactants that are stable
when
separated from one anotller but, when they mix in response to actuation of the
thermic
module by a user, produce an exotllermic reaction or, alternatively, an
endothermic
reaction and thereby heat or cool the contents of the container.
As part of the manufacturing process of such containers which are used for
holding food and beverages, the containers must go through a sterilization
process
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called "retort." In general the retort process consists of subjecting the
container and
food contents to high temperatures and pressures. In a typical retort process,
the
container and contents are placed in a chainber for several minutes at 252
degrees
Fahrenheit and two bars of pressure. Accordingly, the containers must be
designed to
withstand the retort process and still function properly.
The heating or cooling module (thermic module) is typically attached at one
end of the cylindrical container body, and the elongated cylindrical reaction
chamber
.portion of the module extends into the container body. This elongated portion
functions as both a chamber in which to contain the reaction and a heat-
exchanger for
transferring heat between it and the surrounding contents of the container
body. The
thermic module has two chambers, each of which contains one of the chemical
reactants, separated by a breakable barrier such as'nletal foil or a thin
plastic film.
Typically, one of the reactants is a liquid, and the other is in a solid
powdered or
granular form. Calcium oxide (commonly known as limestone) and water are
examples of two reactants lmown to produce an exothermic reaction to heat the
contents in such containers. Other combinations of reactants are known to
produce
endothermic reactions to cool the container contents. A cap containing the
liquid
reactant is disposed in the end of the thermic module attached to the
container body.
At one end of the cap is an actuator button that a user may press to initiate
the heating
or cooling. The barrier seals the other end of the cap. The cap has a pushrod
or
similar prong-like member that extends from the actuator button nearly to the
barrier.
Depressing the actuator button forces the prong into the barrier, puncturing
it and
thereby allowing the liquid reactant to flow into the solid reactant in the
reaction
chamber. The heat produced by the resulting exothermic reaction or absorbed by
the
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resulting endothermic reaction is transferred between the reaction chainber of
the
thermic module and the contents of the container body by conduction.
Exothermic
reactions also typically generate a gas and/or steam, which is allowed to
escape
through vents in the end of the container. The user inverts the container and,
when
the contents have reached the desired temperature, consumes the contents. The
second end of the container body has a seal or closure, such as a conventional
beverage can pull-tab, that may be opened and through which the user may
consume
the heated or cooled contents.
A portion of the thermic module, such as the elongated cylindrical reaction
chamber, may be unitarily formed with the outer can, as illustrated, for
example, in
U.S. Pat. No. 3,970,068, issued to Sato, and U.S. Pat. No. 5,088,870, issued
to
Fukuhara et al. The unitary container body is formed by providing a metal
cylinder
that is open at one end and closed at the other, and punching or deep-drawing
a cavity
in the closed end. A cap containing the liquid reactant is attached to the
open end of
the cavity. In other such containers, however, the elongated cylindrical
reaction
chamber may be separately formed and then attached to the container body by
anotlzer
manufacturing step. It would be desirable to provide an economical and
reliable
method for mainifacturing this latter type of container.
The previously known elongated reaction chambers present several other
design drawbacks. For one, the wall of the elongated reaction chamber
separates the
reaction chamber from the material contained in the container which is heated
or
cooled. This wall acts as an insulator which can slow the heating or cooling
of the
material by the thermic module. In addition, in response to the retort
process, the
,
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chambers have suffered excessive deformation and cracking and have shown an
inability to return to their expanded shape after being compressed during
retort.
The retort process also has the potential to cause weakening or failure of the
bond holding the breakable barrier separating the two chambers of the thermic
module. The breakable barrier is typically heat sealed to a circular top edge
of one
chamber of the thermic module. During retort, the pressure of air expanding
under
the barrier tends to push the barrier upward into a dome shape which can cause
the
bond to weaken or detach,
Another problem associated with self-heating and self-cooling containers is
that a person may attempt to consume the contents before the contents have
been fully
heated or cooled. That the person may be displeased by the resulting
temperature of
the beverage or other contents is not the only effect. A perhaps more serious
effect is
that a self-heating container may overheat and present a burn hazard if, after
the user
empties it of its contents, it continues to generate heat, because the
contents act as a
heat sink. It would be desirable to provide a self-heating container that
prevents or
inhibits a user from consuming the contents before the heating reaction has
completed.
As disclosed in the above-referenced U.S. patents, the actuator button may be
protected by a foil safety seal. An unbroken seal assures a person that the
container
has not been actuated and is thus ready for use. Also, the reactivity of
typical
chemicals such as calcium oxide may decrease if they absorb atmospheric
moisture,
such as could occur if the container were in storage or in transit for
prolonged periods
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in a moist environnlent prior to use, and the seal inhibits exposure of the
reactants to
atmospheric moisture. To use the container, the user peels the foil seal off
the
container and discards it. The removal of the foil seal presents a disposal
problem
because the user may not be within a convenient distance of a trash
receptacle. It
would fiirther be desirable to minimize disposal problems associated with self-
heating
and self-cooling containers.
The present invention is directed to improvements in self-heating containers
which overcome these problems and deficiencies.
SUMMARY OF THE INVENTION
The present invention relates to a container having a container body, a
thermic
module at one end of the body, and a closure at the other end of the body. The
body
may have any suitable generally tubular shape, such as cylindrical or can-
shaped or .
bottle-shaped. The food, beverage, medicine or other material to be heated or
cooled
is contained in a material cavity in the container body. The thermic module
contains a
chemical reactant that is segregated from another reactant in the container.
When a
user actuates the thermic inodule, the reactants mix and produce a reaction
that,
depending upon the reactants, either produces heat, i.e., an exothermic
reaction, and
thereby heats the container contents, or absorbs heat, i.e., an endothermic
reaction,
and thereby cools the container contents.
In accordance with one aspect of the present invention, a plastic thermic
module body is spin-welded to a plastic container body by rotating one
relative to and
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in contact with the other. The frictionally generated heat fuses or welds the
contacting plastic surfaces togetller. The container body may have multiple
layers,
including an oxygen and flavor scalping barrier layer that inhibits oxidation
and
spoilage of the contents. Spin-welding the container body to the module body
in this
manner seals the portion of the iruier layer that is exposed at the annular
end of the
container body between two plastic layers and thereby prevents air or moisture
from
seeping past the outer plastic layer and into the inner layer.
In accordance with still another aspect of the present invention, the thermic
module body has a heat exchanger portion having a pleated wall. The pleated
design
is provided with relatively large radii at the peaks and valleys of the
pleats. The heat
exchanger portion also has a plurality of circumferential grooves which
longitudinally
separate the pleated portions. The large radii and grooves help prevent the
thermic
module from failing under the pressure and temperature of the retort process.
In accordance with another aspect of the present invention, the container
includes a movable cover mounted over the closure. A suitable heat-sensitive
adhesive between the cover and the container iiillibits movement of the cover
until the
temperature has reached a certain threshold. The adhesive bond softens when
the
adhesive reaches approximately that temperature. In an exemplary embodiment of
the
invention, the cover is rotatable. The cover has an opening, and when the
threshold
temperature is reached, the user can rotate the cover tmtil the opening is
aligned with
the closure. The user may then open the closure and consume the contents of
the
container.
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In accordance with still another aspect of the invention, the thermic module
includes a seal, such as a foil disc, between an inner actuator button and an
outer
actuator button. The inner actuator button may be included in a module cap
that holds
the solid reactant. The outer actuator button has one or more apertlues and
also has
one or more prongs directed toward the seal. When the user presses the outer
actuator
button, the prong pLuictures the seal. This actuator structure eliminates the
disposal
problem associated with a removable foil seal. In addition, if for some reason
the
module cap were to become over-pressurized prior to use, the pressure would
force
the iiuzer actuator button against the seal. The seal, in turn, presses
against the prong
and punctures it, thereby relieving the pressure through the apertures in the
outer
actuator button.
In another aspect of the present invention, as an alternative to the outer
actuator button and tamper-evident foil disc, the container comprises a full
panel pull-
off attached to the bottom of the container. A fiill panel pull-off is a
removable cover
like those used on canned foods and is like a typical pop-tab closure (e.g.
the closure
on a soft-drink or soup metal can) except that the lid part that is removable
covers
substantially the entire opening of the container rather than just a small
opening. The
full panel pull-off completely covers the iiu-ier actuator button and may be
made of
ahunimun such that the actuator button cannot be pushed until the full panel
pull-off
is removed. The full-panel pull-off provides a tamper-evident seal and also
protects
the actuator button from being inadvertently pushed. The full panel pull-off
may also
provide a pressure safety release valve. In the event that the breakable
barrier is
pushed without removing the full panel pull-off, pressure will build up inside
the
container because the vent holes in the thermic module vent only to the
interior of the
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full panel pull-off. If the pressure reaches a certain level, the full panel
pull-off will
partially open thereby relieving the pressure.
In yet another aspect of the present invention, a vent hole is provided in the
sidewall at the bottom of the container. Like the full panel pull-off, the
vent hole is a
safety feature which releases pressure from the inside of the therinic module
in the
ev,ent that the reaction is actuated without removing the full panel pull-off.
The
outside wall of the container body may be provided with a swirl or helical
shaped
groove which runs from the vent hole. Attaching the label on the surface of
the
container over the groove creates a conduit leading from the vent hole. In
this way,
steam that exits the container through the vent hole will travel in this
conduit along
the cooler outer surface of the container such that the steam will cool and
condense.
The thermic module may also include a filter disposed in interfering relation
with the vents between the inner and outer actuator buttons to block egress of
any
particles of the solid reactant or the reaction product, and also absorb water
(gaseous
and liquid) during the reaction. The filter may include a disc-shaped portion
between
the inner and outer actuator buttons and an amiular portion between flanges
coupled
to the actuator buttons. The disc-shaped portion may be integrally formed with
the
annular portion prior to assembly of the container and separated from one
another
along an annular perforation line during a manufacturing step in which the
filter
portions are inserted into the thermic module.
In still another aspect of the present invention, the two reactants producing
the
thermal reaction are specially designed calcium oxide particles and water. The
calcium oxide particles are sized and shaped to optimize the heating profile
of the
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container. The particles also comprise additives to affect the reaction. In
another
aspect of the invention, the water is purified and selected additives are
included in the
water to modify the reaction with the calcium oxide particles to optimize the
heating
profile of the container. The ration of water to calciuin oxide is also pre-
determined
to produce the desired heating profile.
The foregoing, together with other features and advantages of the present
invention, will become more apparent when referring to the following
specification,
claims, and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention, reference is now
made to the following detailed description of the embodiments illustrated in
the
accompanying drawings, wherein:
FIG. 1 is a side view of a container of the present invention;
FIG. 2 is a bottom view of the container;
FIG. 3 is a top view of the container with the cap in the closed position;
FIG. 4 is a view similar to FIG. 3, with the cap rotated to the opened
position;
FIG. 5 is an exploded perspective view of the elements of the container;
FIG. 6 is a sectional view taken on line 6--6 of FIG. 1;
FIG. 7 is a similar sectional view showing the container after actuation;
FIG. 8 is a sectional view taken on line 8-18 of FIG. 1;
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FIG. 9 illustrates the manufacturing step of blow-molding the plastic body
elements of the container;
FIG. 10 illustrates the manufacturing step of separating the elements from one
another following blow-molding; and
FIGS. 1 lA-C respectively illustrate the sequence of manufacturing steps that
comprise spin-welding the container body to the module body.
FIG. 12 is an exploded perspective view of the elements of another container
in accordance with the present invention.
FIG. 13 is a sectional view of the container of FIG. 12.
FIG. 14 is a perspective view of the reactant barrier attached to the module
cap
of the container of FIG 12.
FIG. 15 is a graph of transient temperature curves for calcium oxide particles
of various sieve sizes. FIG. 16 is a graph of transient temperature curves for
calcium oxide particles
of various sieve sizes.
FIG. 17 is a graph of transient temperature curves for calcium oxide particles
of various sieve sizes.
FIG. 18 is a graph of transient temperature curves for calcium oxide particles
of various sieve sizes.
FIG. 19 is a graph of reaction / temperature curves for various ratios of
water
to calcium oxide.
FIG. 20 is a graph of reaction / teinperature curves for various ratios of
water
to calcium oxide.
FIG. 21 is a table of mineral components in water that should not be exceeded.
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FIG.22 is a table of additives which may be added to the calcium oxide
reactant.
DESCRIPTION OF PREFERRED EMBODIMENTS
As illustrated in FIGS. 1-8, a container 10 includes a container body 12, a
thermic module body 14, and a therinic module cap 16. As best illustrated in
FIGS.
5-7, module body 14 has an elongated heat-exchanger portion that extends into
container body 16. The interior of this portion defines a reaction chamber in
which
the reaction occurs that heats (or, in alternative embodiments of the
invention, cools)
the beverage or other contents 18. The heat-exchanger portion has a corrugated
or
pleated wall to increase surface area and, as a result, heat transfer.
Although in the
illustrated embodiment the wall is corrugated or pleated, in other embodiments
the
wall may have other suitable geometries. Module cap 16 is press-fit in the
open end
of module body 14. An endcap 20 with a pop-tab closure 22 of the type commonly
used in beverage cans is crimped over the other end of container body 12 in
the
nianner of a conventional beverage can.
Module cap 16 is of unitary construction and is made of a semi-rigid plastic,
such as high density polyethylene. Module cap 16 has a disc-shaped or dome-
shaped
inner actuator button 24 and a cylindrical prong 26 with an elongated notch
28. A
breakable reactant barrier 30 made of metal foil is adhesively attached to the
open end
of module cap 16 to seal the water or other liquid reactant 32 inside.
Module cap 16 has multiple vent channels 34 distributed around its outside
surface. When module cap 16 is fit in the open end of module body 14, each of
vent
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channels 34 provides a channel through which gas can escape during the
reaction.
Vent channels 34 extend longitudinally along the outside surface of the body
portion
of niodule cap 16, change direction to extend radially along the lower surface
of the
flange portion 36 of module cap 16, change direction again to extend
longitudinally
along the outside cylindrical surface of flange portion 36, and change
direction again
to extend radially along the upper surface of flange portion 36. This long,
narrow,
zig-zag path of chamlels 34 inhibits escape of particles of the calcium oxide
or other
solid reactant 38 while allowing gas to vent.
A filter ring 40 is sandwiched between flange portion 36 and thermic module
body 14. Filter ring 40 fiirther prevents solid particles from escaping
through vent
channels 34 while allowing gases to vent unimpeded. Filter ring 40 may be made
of
any suitable filter material such as synthetic sponge, open-cell foamed
rubber, or any
woven or fibrous materials such as paper and cloth. A suitable material is
commercially available from Filter Material Corporation of Wisconsin under the
product number AC20.
An outer actuator assembly 40 is attached to the end of container body 12 and,
as best illustrated in FIG. 2, includes a ring portion 44 and an outer
actuator button 46.
The ring of squares shown around the outer periphery of ring portion 44 in
FIG. 2 are
surface features that facilitate spin-welding outer actuator assembly 42 to
the end of
container body 12 as described below. Outer actuator button 46 is supported on
at
least three but preferably four spline-shaped fingers 48, suspending it in a
resiliently
deflectable manner within the interior of ring portion 44. Outer actuator
button 46,
fingers 48 and ring portion 44 are preferably unitarily formed as a molded
plastic part.
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The concentric rings shown within outer actuator button 46 in FIG. 2 are
surface
features that provide a frictional grip for user's finger when actuating the
container as
described below. A filter disc 50, preferably made of the same material as
filter ring
40, is sandwiched between outer actuator asseinbly 42 and inner actuator
button 24.
Although filter ring 40 provides an adequate filter by itself, filter disc 50
may be
included in certain embodiments of the invention to further enhance filtering.
An
advantage in manufacturing economy may be achieved in such embodiments by
forming filter ring 40 and filter disc 50 as a unitaiy part with perforations
between
them, and handling them as a unitary part until they are separated during the
manufacturing step in which they are assembled into container 10.
As illustrated in FIGS. 5-7, outer actuator assembly 42 further includes an
breakable actuator barrier 52. Breakable actuator barrier 52 is preferably
made of
metal foil that is adhesively attached to the end of an annular cuff portion
54
projecting from the interior periphery of ring portion 44. Three pointed
projections 56
extend from the underside of outer actuator button 46 toward actuator barrier
52. The
star-shaped or x-shaped surface feature centered at the middle one of
projections 56
reinforces outer actuator button 46 but is not otherwise significant to the
invention.
As illustrated in FIGS. 3-5, lid 58 is mounted over endcap 20 and the end of
container body 12. Lid 58 has two apertures 60 and 62. As illustrated in FIG.
8, lid 58
is mounted to the end of container body 12 with patches or spots of heat-
sensitive
adhesive (labeled "A") having an adhesion strength that, generally speaking,
decreases witli an increase in temperature. Thus, the adhesive immobilizes lid
58
until container 10 is actuated and produces heat. A range of such heat-
sensitive
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adhesives are commercially available with various specifications. One
parameter that
can typically be specified is the tlueshold temperature at which the adhesive
loses (or,
conversely, achieves) substantial adhesion strength. Suitable adhesives are
manufactured by National Starch and Chemical of Illinois under the product
numbers
34-2780 and 70-4467. Although its precise formulation is proprietary to the
manufacturer, the manufacturer describes the adhesive as starch-based. Before
a user
actuates container 10, cap 58 is in the position shown in FIG. 3. In this
position
aperture 60 is not aligned with pop-tab closure 22 and thus prevents a user
from
opening closure 22. Also, in this position aperture 62 is not aligned with the
sealed
opening 64 through which beverage 18 can be consumed. When container 10 heats
and the adhesive reaches the tlireshold teinperature, it loses sufficient
adhesion
strength that a user can move cap 58. The user rotates cap 58 until it is in
the position
shown in FIG. 4, as indicated by the arrow. In this position aperture 60 is
aligned with
pop-tab closure 22, tllereby allowing the user to open it. Also, in this
position
aperture 62 is aligned with the sealed opening through which the user can
consume
the beverage. As in a conventional soft drink can, opening pop-tab closure 22
breaks
the seal and allows a user to drink beverage 18 through the resulting opening.
The
user's lips contact the relatively cool plastic of cap 58 rather than the
potentially very
hot metal of endcap 20.
Although exactitude in the threshold temperature is not necessary for the
invention to work properly, it is preferable in a container for a beverage
such as coffee
or tea that the adhesive maintains substantial adhesion when its temperature
is below
about 100 degrees Fahrenheit (38 Celsius) and loses substantial adhesion when
its
temperature exceeds said this threshold. The preferred adhesive noted above
that is
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manufactured by National Starch and Chemical has this property. For purposes
of
this patent specification, the term "substantial adhesion" refers to the
inability of a
user to rotate lid 58 by exerting iio more than the normal amount of torque
that a
person typically exerts when opening a jar or other screw-top food or beverage
container without the assistance of tools. Although the adhesion strength of
such
adhesives continues to decrease to some extent with an increase in temperature
over a
fairly wide range, the adhesion strength decreases much more sharply at the
threshold
temperature than at other temperatLUes in the range.
To actuate container 10, the user depresses outer actuator button 46 by
exerting a force upon it in the general direction of the longitudinal axis of
container
10. As noted above, actuator button 46 is suspended by fingers 48, which
resiliently
deflect to allow button 46 to move in this axial direction. The force exerted
upon
outer actuator button 46 urges its projections 56 into actuator barrier 52,
puncturing it.
The force further urges outer actuator button 46 toward inner actuator button
24,
which in turn is urged in the same axial direction. Inner actuator button 24
is flexible
and responds to the force by popping or snapping inwardly toward reactant
barrier 30.
In response to the inward flexure of imler actuator button 24, the distal end
of
prong 26 punctures reactant barrier 30. Water 32 flows through punctured
reactant
barrier 30 and mixes with solid reactant 38 in the reaction chamber, i.e., the
interior of
the elongated portion of thermic module body 14. Notch 28 in prong 26
facilitates the
flow of water 18 into the reaction chamber. The resulting exothermic reaction
produces heat, which is transferred to beverage 18 by conduction through the
pleated
wall of the heat-exchanger portion of thermic module body 14. As noted above,
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other embodiments of the invention, other reactants may be selected that give
rise to
an endothermic reaction when mixed.
Gas or steam produced in the reaction escapes the reaction chamber through
vent channels 34, but any solid particles are filtered out by filter ring 40
or filter disc
50. Note that the inherent saturation of filter ring 40 and filter disc 50 by
the escaping
steam may enhance this filtration. The gas or steam that passes through filter
ring 40
or filter disc 50 passes through the punctured actuator barrier 52 and exits
container
through the spaces between fingers 48.
The user can then invert container 10 and wait until the reaction heats
beverage 18, which typically occurs within about five minutes in a container
10
having a capacity of 10 fluid ounces (296 ml) of water or comparable beverage
such
as coffee or tea. As described above, when beverage 18 is heated to the
temperature
at which it is to be consumed, the adhesive has loosened sufficiently to allow
the user
to rotate cap 58. Patches or spots of a suitable lubricant (labeled "L" in
FIG. 8) are
interspersed with the adhesive patches so that when cap 58 is rotated the
lubricant
smears and prevents the adhesive from re-adhering cap 58 as it begins to cool
and also
allows the user to more easily rotate cap 58. The lubricant is preferably food-
grade or
approved for incidental food contact by the appropriate goveriunental
authority, such
as the Food and Drug Administration in the United States. The user then opens
pop-
tab closure 22 as described above and consumes beverage 18.
The method of manufacturing container 10 may include the steps illustrated in
FIGS. 9, 10 and 11 A-C. The manufacturing method is an iinportant aspect of
the
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invention because it addresses several problems. Container body 12 and thermic
module body 14 are preferably made of multiple layers, including an oxygen-
barrier
layer, to maintain the freshness and stability of beverage 18 or other
contents. Such
multiple-layer plastic container technology is familiar to persons of skill in
the art to
which the invention relates and is described in, for example, Blow Molding
Handbook, edited by Donald Rosato an.d Dominick Rosato, Hanser Publishers. As
known in the art, a multiple-head blow-molding machine such as that
illustrated in
FIG. 9 can be used to produce multiple-layer plastic containers. In accordance
witll
the blow-molding method, the machine positions a suitable mold 66 beneath the
blow-molding head (known as a W. Mueller head), extrudes the plastic resin
layers
simultaneously, and then injects air to conform the plastic to the contours of
the mold
cavity. The machine then cools the mold, opens it, removes the molded part,
and
repeats the process. A suitable blow-molding machine is commercially available
from B&W of Berlin, Germany under the name/Model No. DE3000. Although this
machine can work with two or more molds simultaneously, this aspect is not
particularly relevant to the manufacturing method of the present invention.
Important to manufacturing econoiny is that mold 66 is configured to produce
one container body 12 and one thermic module body 14 as a single unitarily
molded
part. As illustrated in FIG. 10, a static trimming machine cuts this part at
three places
to separate it into container body 12, thermic module body 14, and two moyles
16 and
18. As known in the art, a moyle is excess or scrap material that may be
included in a
molded part to facilitate molding and handling. The static trimming machine
includes
rollers (not shown) that bear against moyle 16 and rotate the part, as
indicated by the
arrow. The machine rotates the part against a hot luiife blade 68 that can be
extended
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for cutting and then retracted. Knife blade 68 separates or cuts moyle 16 from
the
remainder of the part. The saine or a similar machine performs a similar
cutting
operation that separates moyle 18. The use of a static trimining machine is
important
to the manufacturing process because it leaves a smooth surface at the flange-
like end
of thermic module portion 14 to facilitate the welding step described below.
While
the blow-molding and cutting steps are believed to be important steps of the
overall
manufacturing process described herein, attention should be focused upon the
step in
which thermic module body 14 is attached tocontainer body 12 by spin-welding,
as
illustrated in FIGS. 11A-C. Spin-welding is a method familiar to persons of
skill in
the art, by which the plastic of two parts fiises as a result of friction
induced by
spinning or rotating one part relative to the other. A suitable spin-welding
machine is
commercially available from TA Systems of Michigan. As illustrated in FIG. 1
lA,
thermic module body 14 is inserted into the end of container body 12, and the
resulting assembly is placed over a cylindrical tubular support (not shown) of
the
machine. As illustrated in FIG. 11B, the machine has a rotary head that lowers
into
contact with the flang-like surface of module body 14. The machine applies
pressure
that maintains module body 14 firmly in contact with container body 12. The
head
then begins rotating or spinning while maintaining that pressure. The rotating
head
spins module body 14 with respect to container body 12, which is kept
stationary by
the support on which it is niounted, as a result of the frictional engagement
between
the rotating head and the flange-like portion of module body 14. The friction
between
module body 14 and container body 12 fuses or welds them together. It is
significant
that pressure is applied before rotation begins and is maintained until the
parts have
ftised because this sequence results in a more precise weld.
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Note that the cutting step of the process exposes the cross-section of layers,
such as the oxygen and flavor scalping barrier layer, in container body 12 and
module
body 14. While the layers are very thin and difficult to see with the unaided
eye, they
are sufficiently exposed that they are susceptible to degradation by
atmospheric
nloisture and oxygen. Spin-welding is highly advantageous because, unlike
other
potential methods for attaching these parts to one another, spin-welding in
the manner
described above seals the exposed ends of container body 12 and module body
14,
thereby inhibiting atmospheric moisture, oxygen or other contaminants from
contacting and consequently degrading the oxygen barrier or other sensitive
layers of
container body 12. Also, the smooth and square surface left by the rotary
cutter is
more readily sealed by the spin-welding; spin-welding a jagged or uneven edge
may
not completely seal the sensitive interior layers.
Outer actuator assembly 42 may be spin-welded to the end of container body
12 as well. The ring of square recesses on its surface (see FIG. 2)
facilitates
engagement by a spin-welding head having a corresponding ring of square
protuberances (not shown).
In another aspect of the present invention, FIG. 12 illustrates another
container
100 in accordance with the present invention. Many of the features and
elements of
the container 100 are the same or substantially similar to the features and
elements of
the container 10 described above. The present invention contemplates that many
of
the features of the container 100 can be substituted for the features in the
container 10,
and vice versa. Accordingly, it should be understood that any one or more
features of
container 100 and container 10 can be substituted for analogous features in
the other
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container within the scope of the present invention witliout describing in
detail each
and every combination herein.
Turning to FIGS. 12 and 13, the container 100 includes a container body 112,
a thermic module body 114, and a thermic module cap 116. The module body 114
has an elongated heat-exchanger portion 115 that extends into container body
112.
The interior of this portion defines a reaction chamber in which the reaction
occurs
that heats (or, in alternative embodiments of the invention, cools) the
beverage or
other contents 118. Typically, a first reactant 132 is contained in the
thermic module
cap 116. A second reactant 138 is contained the thermic module body 114. The
two
reactants are separated by a breakable reactant barrier 130. In general, one
of the
reactants is a liquid, such as water, and the other reactant is in a solid
powdered or
granular form, such as calcium oxide.
The heat-exchanger portion 115 of the module body 114 has a corrugated or
pleated wall to increase surface area and, as a result, heat transfer.
Although in the
illustrated embodiment the wall is corrugated or pleated, in other embodiments
the
wall may have other suitable geometries. For a given material, the thinner the
wall of
the heat exchanger portion 115, the faster the heat transfer between the
reactants 132
and 138 and the beverage 118. Hence, the wall is made very thin, preferably
having a
thiclaiess between 0.004 inches and 0.012 inches. In another aspect of the
pleated
design of the heat exchanger portion 115, the peaks 117 and valleys 119 of the
pleats
have generous radii, preferably greater than 0.05 inches, more preferably
greater than
0.06 inches. The large radii of the peaks 117 and valleys 119 prevents the
thin walls
from failing during the retort process. Further, two circular grooves 121 and
123 are
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WO 2006/101482 PCT/US2005/008840
provided. The grooves 121 and 123 facilitate folding at the grooves when the
heat
exchanger portion 115 is subjected to pressure as during the retort process.
The
folding helps prevent the thin walls of the heat exchanger portion 115 from
creasing
and cracking. The pointed end of the conical end of the heat exchanger portion
has a
thickened rib 125 extending therefrom. The rib 125 helps reduce deformation of
the
cone during the retort process.
The module cap 116 is press-fit in the open end of module body 114. Module
cap 116 is of unitary construction and is made of a semi-rigid plastic, such
as high
density polyethylene. The breakable reactant barrier 130, preferably made of
metal
foil, is attached to the open end of module cap 116 to seal the water or other
liquid
reactant 132 inside. The reactant barrier 130 may be attached to the open end
of
module cap 116 by thermal bonding, ultrasonic bonding, use of an adhesive or
any
other suitable method. Module cap 116 has a disc-shaped or dome-shaped
actuator
button 124 and a cylindrical prong 126 with an elongated notch 128. An adapter
puck
127 may also be provided to prevent the granular reactant 138 from falling
into the
bottom of module cap 116. Some reactants 138 may burn a hole through the
bottom
of the nlodule cap 116. The adapter puck 127 includes an amlular disc portion
wliich
fits inside the module cap 116 and a plurality of prongs 129 extending
perpendicularly
from both sides of the disc portion. The prongs 129 extending toward the
barrier 130
improve the breakage of the barrier 130 when the thermic module is actuated to
puncture the breakable reactant barrier 130.
While the reactant barrier 130 may be attached to just the top annular surface
of the open end of module cap 116, it is preferable that the reactant barrier
130 extend
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over the open end and down the side of the outer wall of the module cap 116 as
shown
in FIG. 14. Where the reactant barrier 130 is attached to the module cap 116
by
thermal bonding, the thermal bonding process forms a radius on the outer edge
of the
top annular surface. The radiused edge fiirther improves the bonding of the
reactant
barrier 130 to the module cap 116. When the container 100 is subjected to the
retort
process, pressure tends to push the barrier 130 upwards away from the top of
the
module cap 116. By sealing the barrier 130 to the side of the outer wall of
the module
cap 116 creates a much stronger adhesive seal by increasing the shear strength
of the
bond.
Module cap 116 has a plurality of ribs 134 protruding from the upper and
lower surfaces of the flange portion 136 of module cap 116. The ribs 134
create
channels between the flange portion 136 and the surrounding structure for
venting
pressure. The outer wall of the module cap is also provided with ribs 135 to
create a
vent channel between the outer surface of the module cap 116 and im-ier
surface of the
module body 14. When nlodule cap 116 is fit in the open end of module body
114,
the vent channels created by the ribs 134 and ribs 135 each of vent channels
34
provides a channel tllrough which gas can escape during the reaction. The vent
spaces extend longitudinally along the outside surface of the body portion of
module
cap 116, change direction to extend radially along the lower surface of the
flange
portion 136 of module cap 116, change direction again to extend longitudinally
along
the outside cylindrical surface of flange portion 136, and change direction
again to
extend radially along the upper surface of flange portion 136. This long,
narrow, zig-
zag path of chamiels ii-Aiibits escape of particles of the calcium oxide or
other solid
reactant 138 while allowing gas to vent.
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A filter ring 140 is sandwiched between flange portion 136 and thermic
module body 114. Filter ring 140 fiirther prevents solid particles from
escaping
through the vent channels while allowing gases to vent. Filter ring 140 may be
made
of any suitable filter material such as synthetic sponge, open-cell foamed
rubber, or
any woven or fibrous materials such as paper and cloth. A suitable material is
commercially available from Filter Material Corporation of Wisconsin under the
product number AC20.
Instead of an outer actuator assembly 46 as in the container 10, the container
100 has a full panel pull-off 146 attached to t11e bottom end of the container
body 112.
The fiill panel pull-off 146 may be attached to the container body 112 by
crimping, or
any other suitable method. Alternatively, the fiill panel pull-off 146 may be
attached
to the bottom of the module cap 116. The full panel pull-off 146 is a
removable lid of
the type commonly used on canned foods and is like a typical pop-tab closure
(e.g. the
closure on a soft-drii-ilc aluminum can) except that the removable lid part
covers
substantially the entire opening of the container rather than just a small
opening. The
full panel pull-off 146 completely covers the opening at the bottom end of the
container body 112. In this position, the pull-off 146 also covers the
actuator button
124. The pull-off 146 preferably comprises a closure with a weakened region in
a
circular-shape along which the pull-off lid 141 breaks away from the remainder
of the
pull-off structure. The pull-off 146 is made of a material having sufficient
strength,
rigidity and thicl:ness such that the actuator button 124 cannot be pushed
without
removing the pull-off 146, except in the case of extreme misuse or
mishandling. For
example, the pull-off may be made of aluminum or other material having similar
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strength and rigidity. The pull-off lid 141 is connected to a pull-ring 144
which is
lifted and then pulled away from the pull-off lid 141 to remove the pull-off
lid 141.
Because the pull-off lid 141 breaks away from the rest of the pull-off 146
along the
weakened region, it cannot be replaced once it is removed. Hence, the ftill-
panel pull-
off 146 provides an excellent tamper-evident seal while also making the
container 100
less susceptible to vandalism while on store shelves. The pull-off 146 also
functions
as a pressure safety release valve. In the event that the reactant barrier 130
is pushed
without removing the pull-off 146, pressure will build up inside the container
because
the vent channels in the thermic module cap 116 vent only to the interior of
the pull-
off 146. If the pressure reaches a certain level, the wealcened region of the
pull-off
146 will partially rupture thereby relieving the pressure.
A vent bole 131 may be provided in the sidewall of the bottom of the therinic
module body 114. The vent hole 131 provides a vent path from the reaction
chamber
to the outside atmosphere. Similar to the safety pressure relief function of
the pull-off
146 described above, the vent hole 131 releases pressure from the reaction
chamber in
the event that the thermic reaction is inadvertently actuated without removing
the
pull-off 146.
In addition to the vent hole 131, a coiled groove 133 may be molded into the
outside wall of the container 112. The groove 133 starts at the location of
the vent
hole 131 and extends in a coil shape around and up the outside wall of the
container
112. When a label (not shown) is adhesively mounted over the outside wall of
the
container, a conduit is formed by the label and the groove 133. Steam that
exits the
vent hole 131 will travel through the conduit formed by the groove 133 and the
label
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WO 2006/101482 PCT/US2005/008840
along the cooler outer surface of the container 112 causing the steam to cool
and
condense.
The label (not shown) may be formed of a plasti-shield labeling material or
other insulatin<,, material such as a thin sheet of styrofoam. This reduces
the ainount
of heat that a person feels in their hands when they are consuming a hot food
or
beverage from the container 112. The label can be pre-printed prior to
adhesive
application to the outside wall of the container 112.
An endcap 120 with a pop-tab closure 122 of the type commonly used in
beverage cans is crimped over the other top of container body 112 in the
manner of a
conventional beverage can. A lid 158 is mounted over endcap 120 and the end of
container body 112. Lid 158 has two apertures 160 and 162. The lid 158 is
mounted
to the end of container body 112 with patches or spots of heat-sensitive
adhesive
(labeled "A") as shown in FIG. 8 for container 10) having an adhesion strength
that
decreases when heated to a specific threshold release temperature. Thus, the
adhesive
immobilizes lid 158 until container 100 is actuated and produces heat. This
adhesive
is the same adliesive as described above for container 10. As with container
10
described above, patches or spots of a suitable lubricant (labeled "L" in FIG.
8 for
container 10) are interspersed with the adhesive patches so that when cap 158
is
rotated the lubricant smears and prevents the adhesive from re-adhering cap
158 as it
begins to cool and also allows the user to more easily rotate cap 158. Before
a user
actuates container 100, cap 158 is in the same position shown in FIG. 3 for
the
container 10. In this position aperture 160 is not aligned with pop-tab
closure 122 and
thus prevents a user from opening closure 122. Also, in this position aperture
162 is
CA 02605359 2007-10-17
WO 2006/101482 PCT/US2005/008840
not aligned with the sealed opening 164 through which beverage 118 can be
consumed.
An indicator (not shown) may be provided on the surface container 100 which
shows when the beverage 118 llas reached the desired temperature. For example,
the
indicator can be a label having a thermochromatic ink which changes color when
it
reaches a predetermined temperature. For example, the ink can be the
Kromathermic
Type 44 red available from Kromacorp International which turns from pink to
white
when heated to a predetermined temperature. When the indicator indicates that
the
beverage has reached a desired temperature, the user can then open the
container 100
and consume the contents.
When container 100 heats and the adhesive reaches the release temperature, it
loses sufficient adhesion strengtll that a user can rotate cap 158. The user
rotates cap
158 until it is in the same position shown in FIG. 4 for container 10, as
indicated by
the arrow. In this position aperture 160 is aligned with pop-tab closure 122,
thereby
allowing the user to open it. Also, in this position aperture 162 is aligned
with the
sealed opening through which the user can consume the beverage. As in a
conventional soft drink cail, opening pop-tab closure 122 breal.s the seal and
allows a
user to drink beverage 118 through the resulting opening. The user's lips
contact the
relatively cool plastic of cap 158 rather than the potentially very hot metal
of endcap
120.
One of the reactants 132 or 138 may comprise specially designed calcium
oxide particles. There are several characteristics of calcium oxide particles
which will
effect their reaction with the water. For example, varying the characteristics
of the
calcium oxide particles can affect such reaction attributes as volatility,
rate of the
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WO 2006/101482 PCT/US2005/008840
reaction, and total amount of energy obtained from the reaction. Based on
these
characteristics, specific calcium oxide particles can be designed and produced
to
attain the desired overall reaction properties.
The porosity of the calcium oxide particles can greatly effect how volatile a
particle will react Nvhen water is added. The processing of calcium oxide
involves
cooking it at 1000 degrees Fahrenheit which drives off moisture and gases that
are
naturally found in the material. This release creates pores in the material.
The
cooking time can be increased to a point where the pores will start to close
back up in
a process call a hard burn. By subjecting the particles to a proper amount of
hard
burn, the volatility of the reaction with water can be reduced to a more
desirable level.
The size of the calcium oxide particles has an effect on how reactive that
particle is. A group of small particles has more surface area that one large
particle of
equal weight. The greater the surface area, the faster and more thorough the
particle
will react when mixed with water. FIGS. 15-18 show transient temperature
curves for
particles of various sieve sizes ranging from a 1/4 inch mesh (largest
particle) through
sieve #30 (smallest particle). In general, the curves show that smaller
particles will
heat up faster and also attain a higher maximum temperature. Accordingly,
particles
of various sizes may be chosen to produce the desired heating profile for the
specific
application for the container 100. For an application such as heating coffee
or soup, a
preferred distribution of particles sizes is:
Particle Size (mesh) Amount (%)
#7 2% maximum
#14 80% +/- 5%
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#20 15% +/- 5%
Finer than #20 3% maximum
Additives can also be added to the calcium oxide to increase or decrease the
reaction rate. The additives work by several different methods, including
chemically,
mechanically, or physically altering the interface of the calcium oxide with
the water.
One of the most important characteristics effecting the reaction is the
reaction
ratio, i.e. the ration of the calcium oxide to water. The standard ratio is 4
parts
calcium oxide to one part water, by mass. Different reaction / temperature
curves can
be obtained by varying the ratio of calcium oxide to water. For example, it is
possible
to maximize the peak energy produced by any one size of particle or porosity
of a
particle. The ratio can also be altered to slightly increase or decrease the
overall rate
of the reaction. The graphs of FIGS. 19-20 show the reaction / temperature
curves for
various ratios of water to calcium oxide. It can be seen that increasing the
amount of
water to 1.15 parts per 4 parts calcium oxide by mass (i.e. +15% H2O in FIG.
20), the
fastest reaction is obtained and also the most energy of the ratios tested.
The water comprising the other reactant 132 or 138 may also be modified to
optimize its use in the present invention. For example, the water quality is a
critical
component. Any chlorine in the water may cause the breakable barrier 130 to
corrode
and fail. Minute deviations in water quality can adversely affect the thermal
reaction
with the calcium oxide. Trace mineral components in the water should not
exceed the
concentrations shown on the table in FIG. 21.
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Additives may also be added to the water to modify the reaction and improve
the compatibility of the water with the other materials of the container. A
list of
possible additives and their properties is included in the table of FIG. 22.
To actuate container 100, the user first removes the full panel pull-off 146
by
lifting the pull-ring 144 and removing the pull-off lid 141. The user then
depresses
the actuator button 124 by exerting a force upon it in the general direction
of the
longitudinal axis of container 100. The force exerted upon the actuator button
124
causes it to snap or pop inwardly toward the reactant barrier 130.
In response to, the inward flexure of actuator button 124, the distal end of
prong 26 and the prongs 129 of the adapter pucl. 127 puncture the reactant
barrier 30.
The first reactant 132, generally a liquid reactant, flows through punctured
reactant
barrier 30 and mixes with the solid reactant 38 in the reaction chamber, i.e.,
the
interior of the elongated portion of thermic module body 114. The notch 128 in
prong
126 facilitates the flow of water 132 into the reaction chamber. The resulting
exothermic reaction produces heat, which is transferred to beverage 118 by
conduction through the pleated wall of the heat-exchanger portion of thermic
module
body 14. As noted above, in other embodiments of the invention, other
reactants may
be selected that give rise to an endothermic reaction when mixed.
Gas or steam produced in the reaction escapes the reaction chamber through
vent channels created by the ribs 134, but any solid particles are filtered
out by filter
ring 140. Note that the inherent saturation of filter ring 140 by the escaping
steam
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may enhance this filtration. The gas or steam that passes through filter ring
140
passes through the opening left byremoval of the pull-off lid 141.
The user can then invert container 100 and wait until the reaction heats
beverage 18, which typically occurs within about five minutes in a container
100
having a capacity of 10 fluid ounces (296 ml) of water or comparable beverage
such
as coffee or tea. As described above, when beverage 118 is heated to the
temperature
at which it is to be consluned, the adhesive has loosened sufficiently to
allow the user
to rotate cap 158. Patches or spots of a suitable lubricant (labeled "L" in
FIG. 8) are
interspersed with the adhesive patches so that when cap 158 is rotated the
lubricant
smears and prevents the adhesive from re-adhering cap 158 as it begins to cool
and
also allows the user to more easily rotate cap 158. The lubricant is
preferably food-
grade or approved for incidental food contact by the appropriate governmental
authority, such as the Food and Drug Administration in the United States. The
user
then opens pop-tab closure 122 as described above and consumes beverage 118.
The method of manufacturing container 100 may include the same steps
described above for container 10, except where the structure of the containers
100 and
differ.
Obviously, other embodiments and modifications of the present invention will
occur readily to those of ordinary skill in the art in view of these
teachings.
Therefore, this invention is to be limited only by the following claims, which
include
all such other embodiments and modifications when viewed in conjunction with
the
above specification and accompanying drawings.
