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  
       [0001]     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.  
         [0002]     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.  
         [0003]     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  
       [0004]     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.  
         [0005]     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.  
         [0006]     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.  
         [0007]     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  
       [0008]      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.  
         [0009]      FIG. 2  is a section view of the outer shroud of  FIG. 1 .  
         [0010]      FIG. 3  is a enlarged section view showing details of a portion of the shroud of  FIGS. 1 and 2 .  
         [0011]      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.  
         [0012]      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 .  
         [0013]      FIG. 6  is a section view illustrating the assembly of the spike carrier of  FIG. 4  to the shroud of  FIGS. 1 and 2 .  
         [0014]      FIG. 7  is a section view illustrating the assembly of the pushbutton of  FIG. 5  to the subassembly of  FIG. 6 .  
         [0015]      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 .  
         [0016]      FIG. 9  is a perspective view of an insert member that will be used in combination with the subassembly of  FIGS. 1-8 .  
         [0017]      FIG. 10  is a half section view of the insert member of  FIG. 9 .  
         [0018]      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 .  
         [0019]      FIG. 12  is a section view illustrating the placement of an inner container into the insert member of  FIGS. 9-11 .  
         [0020]      FIG. 13  is a section view illustrating the installation of a thermal insulator inside the subassembly of  FIGS. 9-12 .  
         [0021]      FIG. 14  is a section view that illustrates the placement of a steam condenser inside the subassembly of  FIGS. 9-13 .  
         [0022]      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 .  
         [0023]      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 .  
         [0024]      FIG. 17  is a half section view of the subassembly of  FIG. 16 .  
         [0025]      FIG. 18  is a perspective view of a false bottom member that will be installed onto the subassembly of  FIGS. 16 and 17 .  
         [0026]      FIG. 19  is a section view of the false bottom member of  FIG. 18 .  
         [0027]      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 .  
         [0028]      FIG. 21  is a section view of the subassembly of  FIG. 20 .  
         [0029]      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.  
         [0030]      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  
       [0031]     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.  
         [0032]      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.  
         [0033]     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.  
         [0034]     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.  
         [0035]      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.  
         [0036]      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.  
         [0037]     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&#39;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.  
         [0038]      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&#39;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&#39;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&#39;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&#39;s flex resistance and to help it to resume its original shape when a flexing load is removed.  
         [0039]     An outer portion of the container assembly&#39;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&#39;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.  
         [0040]     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.  
         [0041]     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&#39;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 .  
         [0042]     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&#39;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.  
         [0043]     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.  
         [0044]     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.  
         [0045]     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.  
         [0046]     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&#39;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.  
         [0047]     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.  
         [0048]      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&#39;s rim and the insert&#39;s rim channel is tight enough to secure the can firmly to the insert.  
         [0049]      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.  
         [0050]     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&#39;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.  
         [0051]     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&#39;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&#39;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.  
         [0052]     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 ).  
         [0053]     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 .  
         [0054]     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.  
         [0055]     Any other suitable method might be used for joining the assembly&#39;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.  
         [0056]      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&#39;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 .  
         [0057]      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&#39;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 .  
         [0058]     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 .  
         [0059]     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 .  
         [0060]     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.  
         [0061]     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.  
         [0062]      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.  
         [0063]      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.  
         [0064]     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.  
         [0065]     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.  
         [0066]     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.  
         [0067]     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.  
         [0068]     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.