US20060118103A1

US20060118103A1 - Self-contained temperature-change container assemblies

Info

Publication number: US20060118103A1
Application number: US11/002,784
Authority: US
Inventors: H. Joshua Schreff; Massimiliano Rizzi
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-12-02
Filing date: 2004-12-02
Publication date: 2006-06-08

Abstract

A container houses an inner container with food or another product to be heated or cooled. An insert at least partially surrounds the inner container with a first temperature-change reagent inside the insert. A penetrable barrier is disposed between the first reagent and a second reagent. An actuator breaches the barrier to allow the first and second reagents to heat or cool the material inside the inner container. An outer shroud at least partially surrounds the insert. At least one spacer is present between the outer shroud and the insert, with thermally insulating air gaps present adjacent the spacer. The spacer also has an internal vent channel running through it for venting pressure from the internal volume in which the reagents mix to the atmosphere outside the assembly.

Description

BACKGROUND OF THE INVENTION

Self-contained temperature-change container assemblies are known in the art. Such assemblies may use an exothermic or endothermic chemical reaction to generate or absorb heat and thereby to heat or cool a product inside the assembly. The product may be a food or beverage, a cosmetic or a medical product, or anything else that a user would like to have heated or cooled in comparison with the prevailing ambient temperature.
Some such assemblies generate heat in an exothermic reaction by mixing calcium oxide as a first reagent and liquid water as a second reagent. These two reagents may be kept separated by some physical barrier until the product is used. A user of the product may then use some sort of actuator to breach or remove the barrier and allow the calcium oxide to mix. Heat generated in the resulting reaction is transferred to the product inside the assembly, thereby increasing its temperature. Assemblies of this type have been used to heat soups, entrees, hot beverages, and a variety of other products.
Examples of self-contained temperature-change container assemblies are described in co-pending U.S. patent application Ser. Nos. 10/756,954, filed Jan. 12, 2004, and 10/613,322, filed Jul. 3, 2003, which are hereby incorporated by reference in their entireties.

SUMMARY OF THE DISCLOSURE

The invention provides an attractive, practical, and robust self-contained temperature-change container assembly that is practical and inexpensive to manufacture from readily available materials. The assembly houses an inner container, which may be a standard can containing soup, another food or beverage, or some other type of product to be heated or cooled.
The inner container is received in an insert, which at least partially surrounds the inner container and which defines a first internal volume that holds calcium oxide or another first temperature-change reagent.
A penetrable barrier is disposed between the first internal volume and a second internal volume that holds water or another second temperature change reagent. An actuator is present which, when actuated by the user, breaches the barrier to allow the first and second temperature change reagents to mix. The resulting temperature change reaction generates or consumes heat, which is transferred to or from the contents of the inner container. In a preferred embodiment, calcium oxide and water mix in an exothermic reaction that heats soup inside a standard metal can.
The assembly also includes an outer shroud that at least partially surrounds the insert. One or more spacers are present between the outer shroud and the insert, with thermally insulating air gaps present adjacent the spacers. The spacers also have internal vent channels running through them for venting pressure from the internal volume in which the reagents mix to the atmosphere outside the assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an outer shroud that forms a part of a housing assembly in a preferred embodiment of the invention.
FIG. 2 is a section view of the outer shroud of FIG. 1.
FIG. 3 is a enlarged section view showing details of a portion of the shroud of FIGS. 1 and 2.
FIG. 4 is a section view showing a spike carrier that will be used as a part of an actuator in the preferred embodiment of the invention.
FIG. 5 is a section view of a flexible plastic pushbutton that will be used in the actuator with the spike carrier of FIG. 4.
FIG. 6 is a section view illustrating the assembly of the spike carrier of FIG. 4 to the shroud of FIGS. 1 and 2.
FIG. 7 is a section view illustrating the assembly of the pushbutton of FIG. 5 to the subassembly of FIG. 6.
FIG. 8 is a section view depicting the sealing of a film barrier member over a quantity of a liquid reagent contained in the subassembly of FIG. 7.
FIG. 9 is a perspective view of an insert member that will be used in combination with the subassembly of FIGS. 1-8.
FIG. 10 is a half section view of the insert member of FIG. 9.
FIG. 11 illustrates the placement of a filter material in two vent channels that are formed in spacers on the exterior of the insert member of FIGS. 9 and 10.
FIG. 12 is a section view illustrating the placement of an inner container into the insert member of FIGS. 9-11.
FIG. 13 is a section view illustrating the installation of a thermal insulator inside the subassembly of FIGS. 9-12.
FIG. 14 is a section view that illustrates the placement of a steam condenser inside the subassembly of FIGS. 9-13.
FIG. 15 is a section view that illustrates the filling of a granular or powdered solid reagent into the interior of the subassembly of FIGS. 9-14.
FIG. 16 is a perspective view showing a subassembly comprising the inner subassembly of FIGS. 1-8 assembled together with the outer subassembly of FIGS. 9-15.
FIG. 17 is a half section view of the subassembly of FIG. 16.
FIG. 18 is a perspective view of a false bottom member that will be installed onto the subassembly of FIGS. 16 and 17.
FIG. 19 is a section view of the false bottom member of FIG. 18.
FIG. 20 is a perspective view illustrating the fixation of the false bottom member of FIGS. 18 and 19 to the subassembly of FIGS. 16 and 17.
FIG. 21 is a section view of the subassembly of FIG. 20.
FIG. 22 shows the placement of a heat-insulating label over the exterior of the subassembly of FIGS. 20 and 21 to complete the self-contained temperature-change container assembly.
FIG. 23 illustrates the application of peel-away foil bottom and top covers and a snap-on plastic top lid to the assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention is embodied in a self-contained temperature-change container assembly that is assembled around a standard food can or a similar container that holds a food product or another item that will be heated or cooled inside the container. The construction and operation of such a container assembly are described in this document.
FIG. 1 is a perspective view showing an outer shroud 10 that will form a part of a housing assembly that will surround an inner container in a self-contained temperature-change container assembly. FIG. 2 is a section view through the outer shroud.
The outer shroud 10 includes an upper ring portion 12. The shroud tapers from this upper ring portion down to a reduced-diameter lower skirt portion 15. The lower skirt portion has multiple ribs 17 around the perimeter of the skirt. The ribs may extend partway along the height of the shroud as in this drawing, or they may extend further along nearly the full length of the shroud.
Referring now especially to FIG. 2, the outer shroud 10 includes a shroud floor 20 that includes structure that defines a depression 23. The depression will serve as a holding volume or containment region for water or another liquid reagent, as will be described in more detail below.
FIG. 3 is an enlarged section view showing details of structures formed in the middle of the shroud floor 20 near the bottom of the outer shroud 10. More specifically, a through-hole 25 is located in the center of the shroud floor. First and second interior ridges 28 and 30 are formed concentrically around the through-hole so that an internal channel 33 is defined between them around the outside of the through-hole on the inside of the shroud. On the other side of the shroud floor 20, first and second exterior ridges 35 and 37 are formed concentrically around the through-hole with an external channel 40 defined between the two exterior ridges on the outside of the shroud.
FIG. 4 is a section view depicting a spike carrier 43, which serves as a part of an actuator in the self-contained temperature-change assembly. The spike carrier includes a spike platform 45 with several spike penetrators 48 mounted on and facing away from one side of the spike platform. The figure depicts a spike carrier with five spikes - one spike at the center of the spike platform and four arrayed around its edge. (One of the four edge spikes is not visible in the section view presented in FIG. 4.) Different numbers and patterns of spikes or other penetrators may be used as appropriate in particular assemblies.
The spike carrier 43 also includes a center post 50 in the center of the spike platform 45 on the side opposite the spikes 48, and a spike carrier ridge 52 around the center post on the post's side of the spike platform. The center post includes a post groove 55 near the end of the post opposite the platform. The spike platform can be made of an inexpensive and readily available plastic material, which should be relatively rigid so that a force can be transmitted effectively between the end of the center post and the spikes on the carrier.
FIG. 5 is an enlarged section view of a pushbutton 58 that mates with the spike carrier 43 shown in FIG. 4 to form the assembly's actuator. The pushbutton is generally circular and dome-shaped, with a receiver 60 inside the dome and configured to receive and hold the end of the spike carrier's center post 50. A raised engagement ridge 62 around the inner circumference of the receiver is sized to engage with the groove 55 near the end of the spike carrier's post. The pushbutton can be formed of a flexible resilient material such as a plastic that can be deformed under a load but that will also spring back into position when the load is removed. If desired, one or more stiffening ridges 65 can be provided around the inside (as shown) or the outside of the dome to increase the pushbutton's flex resistance and to help it to resume its original shape when a flexing load is removed.
An outer portion of the container assembly's housing is assembled as illustrated in FIG. 6 by passing the center post 50 of the spike carrier 43 through the through-hole 25 in the shroud floor 20 of the assembly's outer shroud 10. One may note that in FIG. 6 that the carrier ridge 52 (see FIG. 4) on the underside of the spike carrier fits into the upper channel 33 between the two ridges 28 and 30 (see FIG. 3) on the floor of the shroud.
External vents 39 are visible in FIG. 6 as openings through the shroud floor 20 near the edge of the shroud 10. These external vents allow pressure communication between the interior and the exterior of the shroud. The outside and the inside of the shroud are thus in pressure communication, in the sense that gas pressure differences will be equalized between these two locations via the external vents.
The pushbutton 58 is next pressed onto the outer shroud 10 as shown in FIG. 7. The spike carrier 43 will need to be held in place (manually or by an appropriate machine element) as this is done, so that the spike carrier's center post will enter the receiver 60 at the center of the pushbutton dome. At the same time, the rim around the upper edge of the pushbutton enters the lower channel 40 between the two ridges 35 and 37 (see FIG. 3) on the underside of the floor 20 of the outer shroud 10.
A liquid reagent 41, which may be ordinary water, is then filled into the volume defined by the depression 23 in the outer shroud 10. That volume is then closed by sealing a penetrable barrier 67 such as a foil or a film over the volume and around the rim of the lower shroud floor's depression as illustrated in FIG. 8. (The arrows in that figure indicate the sealing of the film around this rim.) The film may be sealed onto the outer shroud by heat sealing, with an adhesive, or by any other suitable means.
When no external force is applied to the pushbutton 58, the pushbutton will exert a tensile force on the center post 50 of the spike carrier 43. This force tends to pull the carrier ridge 52 on the underside of the spike carrier into the channel 33 inside the shroud. The same force urges the rim of the pushbutton into the outside channel 40 on the exterior of the shroud. These pieces and forces thus effectively seal the water or other liquid reagent 41 inside the volume 23 in which it is contained inside the shroud.
Sealing the water or other liquid reagent 41 inside the volume formed by the depression 23 in the outer shroud completes a lower housing subassembly portion of the overall assembly. This outer housing subassembly will later be mated with an inner housing subassembly portion in the completed self-contained temperature-change container assembly, as will be described in more detail below.
The inner housing subassembly is assembled around an insert 70, which is illustrated in a perspective view in FIG. 9, and in a half section in FIG. 10. The insert includes an outer rim or flange 72 and an insert skirt 75. One or more vent channels 78 is included on the outside of the skirt. The figures illustrate two such vent channels, but one, two, or more may be present in particular embodiments. One preferred embodiment includes four such vent channels arranged symmetrically (i.e., with an arc of 90 degrees between them) around the periphery of the insert skirt.
The vent channels 78 are open at one end near the edge of the skirt 75, but closed at the other end where the vent channels abut the insert's flange or rim 72. A small vent or opening 80 in the wall of the skirt allows pressure communication between the inside of the skirt and the interior of each of the vent channels, so that gas pressure can be transferred between the skirt interior and the vent channels.
As FIG. 11 illustrates, a strip of filter material 83 is inserted down the length of each of the vent channels 78 before further assembly of the inner housing subassembly. The filter material should be porous enough so that air may pass through it along the length of the filter channel, but of a material fine enough to prevent solids from moving through it and to at least greatly inhibit the flow of liquids through the vent channels. The filter material should have a high internal surface area, so that hot steam that enters the vent channels will condense readily inside the filter material. Natural or synthetic felts may be used as filter materials in this application.
FIG. 12 is a section view illustrating the insertion of a standard metal food or beverage can 85 into the insert 70 to serve as an inner container that holds a consumable product inside the assembly. A rim at one end of the can snaps into a rim channel 88 inside the skirt 75 of the upper insert 70. The fit between the can's rim and the insert's rim channel is tight enough to secure the can firmly to the insert.
FIG. 13 illustrates the placement of a heat insulating material 90 inside the insert 70. The heat insulating material should be a material of relatively low thermal conductivity such as, for example, a thin layer of corrugated cardboard, pressed paper, an expanded polystyrene foam, or the like. The insulating material can be placed as a thin-walled cylinder or a rolled sheet inside the insert, or it may be sprayed onto the inner wall of the skirt 75, as implied by the arrows in FIG. 13. The material may either be sufficiently permeable to pressure, or holes should be created or provided in the material at the locations of the openings 80 in the skirt, so that pressure can be communicated between the interior of the insert and the vent channels 78. Where a material such as a corrugated cardboard is used, no special treatment may be necessary, as pressure can be communicated sufficiently through the cardboard or around it to reach the vent channels.
After the insulating material 90 has been placed inside the insert 72, a steam condenser 92 is placed inside the insert 70 as shown in FIG. 14 between the skirt 75 and the inner container 85. The steam condenser should be a material with a relatively high thermal conductivity and, preferably, a high surface area. Steel wool is one such suitable material, and one that can be placed conveniently inside the insert as a ring of material around the end of the can that is snapped into the rim channel 88. The function of the steam condenser is to condense steam formed inside the skirt and to transfer the heat generated by that condensation to the outer wall of the can and from there into the can's contents. This will also decrease the amount of steam and heat that is transferred into the vent channels and to the exterior of the overall assembly.
After the steam condenser 92 is in place inside the upper insert 70, a typically granular or powdered solid reagent 95 is filled as shown in FIG. 15 into the space inside the upper insert's skirt 75. The solid reagent should be allowed to fill the space between the skirt and the outer wall of the can 85, and should be filled further to cover the end of the can opposite the end whose rim has been snapped into the rim channel 88 of the upper insert. The solid reagent can be filled to a point near the edge of the skirt opposite the upper insert's flange 72, so that the solid reagent is in close contact with both the cylindrical wall and the circular end of the can to insure effective heat transfer between the reagent and the can, and so that the solid reagent can help to support the weight of the can when the upper insert is inverted from the position shown in FIG. 15, as will be the case in the final assembly. In the preferred embodiment, the engagement of the inner container with the rim channel is sufficiently secure so that the inner container would be maintained adequately in place even if the solid reagent were not present to provide support.
Filling the solid reagent into the space inside the skirt 75 of the insert 70 completes an inner housing subassembly, which is shown in a section view in FIG. 15. The next step in the assembly process is to fit the inner housing subassembly into the outer housing subassembly. The outer housing subassembly is inverted from the orientation shown in FIG. 8 (the barrier film 67 will retain the liquid reagent 41 inside the depression 23 in the shroud floor 20) and slipped down over the inner housing subassembly, which is maintained upright in the same orientation as that shown in FIG. 15 (so that the solid reagent will not spill out of the inside of the shroud 10).
The resulting assembly can be seen in FIG. 16, which shows the flexible pushbutton 58 inside the skirt portion 15 of the outer shroud 10 at one end of the assembly, and the rim of the flange 72 of the insert 70 seated against the ring portion 12 of the outer shroud 10. This assembly is also shown as a section view in FIG. 17.
The inner and outer housing subassemblies are fixed together in a preferred embodiment by spin welding. One of the subassemblies is spun rapidly around its center while it is pressed firmly against the other subassembly, which is held fixed. Frictional heating between the two parts fuses them together where the two subassemblies contact one another. The contacting parts of these subassemblies should thus be formed of a plastic or another material for which spin welding is effective. Durable, inexpensive, and easily moldable plastics are known to be suitable for such applications.
Any other suitable method might be used for joining the assembly's components together. These include ultrasonic welding, joining the parts with an adhesive, molding or otherwise manufacturing certain of the parts integral with one another, or any other suitable technique or combination of techniques.
FIG. 17 illustrates two circular lines of contact where spin welds are formed between the inner and outer housing subassemblies in this embodiment. A first spin weld is formed at the location indicated by arrow A, where the rim of the skirt 75 on insert 70 contacts the inside of the outer shroud 10. A second spin weld is formed at a location indicated by arrow B, where the outer shroud's ring portion 12 contacts the flange 72 on the insert 70. While it is widely held by those of skill in the art that spin welds are generally formable at only a single line of contact between two assembled parts, the inventors of this embodiment have discovered that two spin welds can be formed simultaneously at the two lines of contact indicated in FIG. 17.
FIG. 17 implies that the external vents 39 in the floor 20 are aligned after the spin welding with the vent channels 78 on the outside of the insert's skirt 75. Where this is the case, pressure can be communicated between the vent channels and the atmosphere via the external vents. In embodiments in which the external vents are not deliberately aligned with the vent channels during the assembly process, small openings (not shown) can be provided on the outer face of the vent channels 78 for venting pressure into the space between the insert 70 and the shroud 10, and from there to the atmosphere through the vents 39.
After the two housing subassemblies are assembled and fused together, a false bottom 100 is fixed to the underside of the insert 70 around the pushbutton 58. The false bottom is depicted in perspective in FIG. 18, and in half-section in FIG. 19. The false bottom is shown in place in the perspective view of FIG. 20, and in the section view provided by FIG. 21.
The false bottom 100 includes a central opening 103 surrounded by a raised annular guard 105. The guard encircles the pushbutton 58 where it projects through the false bottom, which serves to decrease the likelihood the assembly will be activated by an inadvertent application of force against the pushbutton. Tabs 108 on the false bottom 100 support the false bottom and space it a short distance away from the material of the insert 70.
The false bottom 100 is spin-welded on to the insert 70. FIG. 21 includes an arrow C that illustrates a circular line of contact between the false bottom and the insert around their central openings. The spin weld between these two parts is formed along this line of contact.
The figures show several smaller openings 110 in addition to the relatively large central opening 103 in the false bottom 100. These openings are act as vents for venting pressure to the atmosphere. Three vertical ribs 111 are provided on the guard 105 for engagement with the tool that spin welds the false bottom onto the assembly.
FIG. 22 illustrates the provision of a label 113 over the ribs 17 (see FIG. 20) on the outside of the outer shroud 10. The label may be printed with an appealing image, advertising or nutritional information, and instructions for using the product. In a preferred embodiment, the label can be printed onto a thin sheet of expanded closed-cell foam, which is suitable for the printing of high quality images, which can be gripped comfortably by a user of the assembly, and which is an effective thermal insulator as well. This thermal insulation quality is augmented by the presence of the ribs under the label, as a layer of insulating air is thereby provided between the inside of the label and the outside of the shroud 10 between each of the ribs.
FIG. 23 illustrates the application of a protective foil bottom 115, a protective foil top 117, and a snap-on plastic lid 120 to the assembly. The foil bottom and foil top are thin foil disks secured by an adhesive or any other suitable means to the bottom and the top of the assembly. The foil bottom covers the pushbutton. This guards against inadvertent actuation of the assembly and provides an easily visible indication if the product has been tampered with or actuated before the desired time of use. The foil top and the snap-on lid insure that the top of the assembly is kept clean until the product is used. Each of these elements is easily removed when the user is ready to use the assembly to heat and consume the product inside the inner container.
A preferred embodiment holds soup or a similar edible product inside the inner container 85. When the user wants to eat the soup, he can invert the assembly from its usual orientation as shown in FIG. 22, set it down on a flat surface on its top, and press firmly down on the pushbutton 58. This urges the spike penetrators 48 (see FIG. 21) through the film barrier 67. When the user releases the pushbutton, the spike carrier 43 returns to its usual position, which with draws the spikes from the barrier to allow the liquid reagent 41 to flow through the openings into the barrier and into contact with the calcium oxide solid reagent 95 inside the insert 70. The resulting exothermic reaction generates heat that is transferred into the can to heat the soup.
The reaction will increase the pressure inside the insert 70, and may also generate a certain amount of steam. The pressure inside the insert will be equalized with the atmosphere though, via the openings 80 and the vent channels 78 of the insert, which vent pressure to the atmosphere via the external vents 39 in the floor 20 of the shroud 10. The bulk of any steam produced should be condensed by the steel wool steam condenser 92 and on the interior walls of the housing. The heat of condensation for the steam condensed on the condenser will be transmitted largely from the metal steel wool and into the metal wall of the inner container can 85. Any steam that does enter the vent channels should then be largely condensed inside the felt filter material 83, so that no significant amount of steam, and substantially no liquid or solid reagent particles, is allowed to exit the assembly where it might be noticed by the user.
The first thermal insulator 90 inside the insert 70 insures that heat is transmitted preferentially into the can 85, and not into the plastic materials of the housing. The exterior of the assembly is kept cool enough for comfortable handling by the expanded foam label 113, by the air gaps between the ribs 17 on the shroud 10, and by the additional air gap that is present between inner wall of the shroud and the outer wall of the insert, wherein the structures that define the vent channels 78 act as spacers with a layer of air trapped between the shroud and the insert in the region between each of the vent channels.
After a suitable time (when the soup is hot and ready to eat) the user can flip the assembly back upright and open the can. The can be made openable with a standard can opener as has long been the case with ordinary soup cans, or the can be provided with a conveniently openable pull-tab pop-top as is also frequently the case. The inner container may be empty when the assembly is sold, so that the user can place his or her own food product or another product inside the empty inner container for heating in the assembly. An eating utensil can be provided with each assembly. Where this is the case the utensil may be located conveniently inside the lower shroud skirt 15 (near the pushbutton 58, particularly where the overall assembly is shrink wrapped or otherwise similarly packaged for shipment and sale.
A self-contained temperature-change assembly and a procedures for assembling it have been described as examples of how the invention might be configured and used in a particular embodiment. The invention is not limited to these examples, though, and various modifications or additions will no doubt occur to those of skill in the art. The true scope of the invention should thus be determined primarily by reference to the appended claims, along with the full scope of equivalents to which those claims are legally entitled.

Claims

1. A self-contained temperature-change container assembly, the assembly comprising:

an inner container configured to hold a product whose temperature will be changed by a temperature-changing chemical reaction taking place in the container assembly;

an insert that includes structure that at least partially surrounds the inner container and which at least partially defines a first internal volume that holds a first temperature change reagent;

a penetrable barrier between the first internal volume and a second internal volume that holds a second temperature change reagent;

an actuator operable to breach the penetrable barrier,.wherein breaching the penetrable barrier allows the first and second temperature change reagents to mix in a temperature change reaction that transfers heat between the reagent mix and the contents of the inner container;

an outer shroud that at least partially surrounds the insert;

at least one spacer between the outer shroud and the insert, wherein an air gap is defined between the outer shroud and the insert at a location adjacent said spacer, and wherein a vent channel is defined inside at least one of the spacers;

structure placing the first internal volume and the vent channel in pressure communication; and

structure placing the vent channel and the surrounding atmosphere in pressure communication; wherein the first internal volume and the atmosphere are placed in pressure communication via the vent channel.

2. The container assembly of claim 1, wherein the outer shroud includes structure that at least partially defines the second internal volume that holds the second temperature change reagent.

3. The container assembly of claim 2, wherein the shroud floor includes structure defining a through hole, and wherein the actuator comprises:

a barrier breaching member located inside the shroud on an interior side of the shroud floor;

a button member located outside the shroud floor on an exterior side of the shroud floor opposite the interior side; and

a force transmission member that passes through the through hole between the button member and the barrier breaching member;

wherein pressing on the button member urges the barrier breaching member through the penetrable barrier to allow the reagents to mix and the reaction to proceed.

4. The container assembly of claim 1, and further comprising structure on the actuator that mates with structure on the outer shroud to hold the second temperature change reagent inside the second internal volume.

5. The container assembly of claim 4, wherein the mating structures include a ridge on one of the barrier breaching member and the shroud, wherein said ridge engages with a groove on the other of the barrier breaching member and the shroud to enhance a sealing engagement between the barrier breaching structure and the shroud.

6. The container assembly of claim 1, wherein the actuator includes a flexible pushbutton member that snaps into a groove on the shroud.

7. The container assembly of claim 6, wherein the pushbutton member includes structure defining a receiver that receives and holds a force transmitting member that urges a barrier breaching member through the barrier when a force is applied to the pushbutton.

8. The container assembly of claim 7, wherein the pushbutton member applies a tensile force to the force transmitting member when force is not applied to the pushbutton by a user of the assembly, wherein the tensile force urges the barrier breaching member into sealing engagement with the shroud, and wherein said sealing engagement contributes to the maintenance of the second reagent inside the shroud.

9. The container assembly of claim 1, and further comprising a filter material inside at least one of the vent channels.

10. The container assembly of claim 1, wherein the inner container includes a rim that engages with a rim channel on the shroud to secure the inner container to the shroud.

11. The container assembly of claim 1, and further comprising a steam condenser inside the assembly between the insert and the inner container.

12. The container assembly of claim 11, wherein the steam condenser includes steel wool.

13. The container assembly of claim 1, wherein a sufficient quantity of the first temperature change reagent is present inside the first internal volume to insure contact between the first temperature change reagent and substantially the entire portion of the inner container that is surrounded by the insert.

14. The container assembly of claim 1, wherein the first temperature change reagent is a solid material whose presence helps to maintain the position of the inner container inside the insert.

15. The container assembly of claim 1, wherein the structure placing the vent channel and the surrounding atmosphere in pressure communication includes structure that defines at least one external vent that allows pressure communication through the outer shroud.

16. The container assembly of claim 1, wherein the shroud and the insert are spin-welded together at least two distinct lines of contact.

17. The container assembly of claim 1, and further comprising a guard structure fixed directly to at least one of the insert and the shroud, wherein the guard structure is configured to protect the actuator from inadvertent actuation.

18. The container assembly of claim 17, wherein the guard structure is carried by a false bottom that is fixed directly to the insert.

19. The container assembly of claim 18, wherein the false bottom is spin-welded to the shroud.

20. The container assembly of claim 1, wherein the outer shroud includes a plurality of spaced apart ribs, and further comprising a heat insulative layer applied over the ribs with air between the ribs between the heat insulative layer and the exterior of the shroud.

21. The container assembly of claim 1, wherein the insert is a generally cylindrical member, and wherein the vent channels run along substantially the entire length of the insert's cylindrical wall between opposite ends of the insert.

22. The container assembly of claim 1, wherein the insert and the outer shroud are both generally cylindrical members, and wherein the insert includes a flange at one end that engages with a rim at one end of the shroud.

23. The container assembly of claim 22, wherein the insert's flange carries a channel that engages with a rim on the inner container to secure the inner container to the insert.