HK1179334B - Heat exchange unit for self-cooling containers - Google Patents

Description

Heat exchange unit for self-cooling containers

The present invention is based on the U.S. provisional application entitled "HeateExhangeUnitforSelf-CoolingContainers" filed on 23/4/2010 under application number 61/327,516 and requesting to enjoy the priority of that application.

Technical Field

The present invention relates generally to containers for holding pressurized media, such as self-chilling or self-heating food and beverage containers, and more particularly to an improved heat exchange unit for use in a self-cooling container for cooling a product, such as a food or beverage, wherein the heat exchange unit is secured in the container and contains the pressurized medium.

Background

It has long been desirable to provide a simple, effective and safe device that can be contained in a container, such as a food or beverage container, to cool or heat a product, such as a food or beverage, when desired. With respect to self-cooling containers, different types of devices have been developed to achieve such desired self-cooling, and various types of refrigerants have been disclosed to achieve such cooling. The refrigerant device may be chemically reactive, electrical, and may include gas reactions, and the like. Us patent 2,460,765; 3,373,581, respectively; 3,636,726, respectively; 3,726,106, respectively; 4,584,848, respectively; 4,656,838, respectively; 4,784,678, respectively; 5,214,933, respectively; 5,285,812, respectively; 5,325,680, respectively; 5,331,817, respectively; 5,394,703, respectively; 5,606,866, respectively; 5,692,381, respectively; 5,692,391, respectively; 5,655,384, respectively; 6,102,108, respectively; 6,105,384, respectively; and 6,125,649, discloses typical structures for such devices.

Self-cooling devices used in the prior art examples disclosed in the above-listed patents are generally less than satisfactory. Some problems are encountered in that these devices, which generally rely on toxic or environmentally unfriendly chemicals, require very large pneumatic circuits and cannot be economically used in small containers such as beverage or food cans, are rather complex and therefore expensive to manufacture and maintain and ineffective. In addition, it has been found that if the pressure in the heat exchange unit increases to a predetermined amount, the portion of the heat exchange unit carrying the transfer valve may be stressed to the extent that it becomes dislodged, thereby causing the heat exchange unit to rupture and become unusable, or in the worst case, causing the vessel to fail altogether.

Reference is now made more particularly to figures 1, 2 and 3, which show three different embodiments of the known container in which a Heat Exchange Unit (HEU) is provided for cooling the beverage contained in the outer container.

As shown in fig. 1, the container (10) includes a heat exchange unit (24) disposed therein, which is surrounded by the beverage (26) to be cooled. The container includes a lid (18) comprising a conventional tab (12) secured to a panel (14) such that upon pulling up the tab (12), the panel (14) flexes into the container (10). The operation of a tab (12) to extend a tear panel (14) into a container (10) is well known in the art. The lid (18) typically includes an angled ridge (20) that is clamped to the top end (22) of the container (10). The HEU (24) contains a cooling medium that can increase in pressure under different circumstances and if the pressure is high enough, the upper portion (28) of the HEU (24) including the crimp (30) securing the valve (32) to the HEU may bulge or crack, thus causing the appliance to fail.

Fig. 2 shows another prior art container (40) having an HEU (50) disposed therein surrounded by a beverage (42) to be cooled. The top of the beverage container (44) is shown (46) with a conventional pull ring (48) as described above. The HEU (50) includes a transfer valve (52) secured to a cap (54) that fits over and is secured to the top of the HEU (50). The valve (52) is carried by a skirt or flange (54) which is held in place by being crimped over the top (56) of the cap (54). A protective cap (58) is provided on the actuating stem of the valve (52) to protect it from accidental actuation. The HEU (50) and valve (52) are secured to the bottom (62) of the tank (44). Furthermore, if the pressure of the pressurized medium contained within the HEU (50) becomes too high, resulting in a rupture between the cap (54) and the body of the HEU (50), the device will be rendered unusable as a result.

Referring now specifically to fig. 3, there is shown yet another embodiment of a beverage cooling container (112) of the prior art, which includes an HEU (120) having an adsorbent (138) therein, which in the presently preferred embodiment is activated carbon that receives carbon dioxide under pressure introduced through a valve mechanism (124) for passage through an opening (128) into an interior portion of the HEU for adsorption by the carbon. The valve (124) is held in place by the flange (122), which is crimped into a reduction in the top portion (132) of the HEU (120). A protective cap 150 is positioned over the actuator rod (130) of the valve (124) to protect it from inadvertent actuation. When the actuating rod (130) is depressed, carbon dioxide is desorbed from the activated carbon to cool the beverage (114). The top (116) of the container (112) includes a conventional pull ring (not shown) as described above. Furthermore, if the pressurized carbon dioxide contained inside the HEU (120) is over-pressurized, the reduced portion in the portion (134) of the HEU (120) will move outward, resulting in the release of the valve and rendering the device unusable.

Accordingly, there is a need for a device that can be placed within a container and function as a HEU to cool a container containing contents such as food or beverages that is simple, efficient, and safe even at relatively high pressures.

Disclosure of Invention

An improved HEU for use in a self-cooling container, the HEU comprising a metal housing having a closed bottom and an open top, a compressed adsorbent material disposed inside the housing, and a metal top section having a hard curl (soliddcurl) at an open upper end of the metal top section that fits outside the open end of the housing and is secured to the outer surface of the housing by a metal-to-metal adhesive that bonds the top section to the housing.

Drawings

FIGS. 1, 2 and 3 illustrate the prior art;

FIG. 4 is a perspective view of a complete HEU assembly constructed in accordance with the principles of the present invention;

FIG. 5 is a perspective cross-sectional view of the HEU shown in FIG. 4 taken along line 5-5 of FIG. 4;

FIG. 6 is a perspective view of the top section of the HEU shown in FIG. 4 shown in cut-away view;

fig. 7 shows in perspective a partial cross-section of an attachment portion of an HEU top section attached to an HEU housing.

Detailed Description

Referring now more particularly to fig. 4, this figure shows a HEU (200) having a metal housing (202) and a metal top section (204) secured to the top of the housing (202), as will be described in more detail below.

The upper portion of the top section (204) of the HEU terminates in an opening (206) defined by a stiff curl (208). The hard crimp (208) receives a valve mechanism of the type described by the prior art described above, which is carried by a conventional mounting member having a seat in which is seated a suitable delivery valve sealingly secured. The valve comprises a conventional stem which extends through a central opening in the seat and over a safety device which can be opened under overpressure. The mounting member is inserted into the top section and an opening (206) at its outer periphery and is secured to the curl (208) by a crimping operation, as is well known to those skilled in the art. The crimping operation not only secures the valve assembly to the HEU (200), but additionally closes and seals the can and the open upper end of the HEU, typically by securing it to the can using a gasket (not shown). A more detailed explanation of the operation of the valve and crimping can be found in us patent 6,105,384, which is incorporated herein by reference, and is substantially as shown in figure 3 of the said document and described above.

The heat exchange unit (200) may comprise any refrigerant medium known in the art, the function of which is to conduct heat contained in the beverage to the atmosphere once the heat exchange unit has been actuated to escape the refrigerant. The above-mentioned prior patents have disclosed various types of refrigerants. However, the preferred refrigerant medium for use in the present invention is an adsorbent/desorbent mechanism which preferably employs as the adsorbent a material such as zeolite, cation exchange zeolite, silica gel, activated carbon, and carbon molecular sieves. These adsorbents are capable of adsorbing large quantities of gas under pressure for subsequent release. The gas adsorbed therein may be any suitable gas that is conducive to the environment. According to the invention, preferably the gas comprises carbon dioxide. Carbon dioxide adsorbed in the adsorbent, preferably activated carbon particles, will undergo a significant drop in temperature when released to atmospheric pressure, thereby cooling the beverage contents in contact with the outer surface of the heat exchange unit (200). A more detailed description of a carbon-carbon dioxide adsorbent refrigeration system is contained in U.S. patent 7,185,511, which is incorporated herein by reference. Accordingly, further and more detailed explanation of the carbon-carbon dioxide refrigeration system will not be provided in this specification.

As shown in fig. 5, the metal housing (202), which preferably is formed of impact extruded aluminum (impactedextruded aluminum), has a closed bottom (203) and an open top (205) that terminates in an edge (207). A preformed carbon member or plug (210), which is a highly compacted solid, preferably composed of activated carbon particles and graphite material and binder, is inserted and received within the interior of the HEU casing and extends generally upwardly and adjacent the upper perimeter (212) of the HEU casing. The maximum amount of sorbent material can be contained within the HEU by using an open-ended shell and a preformed plug (210) of carbon material. Once the valve is secured in place on the top section (204), a pressurized medium, such as carbon dioxide, can be passed through the valve into the interior of the HEU (200) and adsorbed by the compacted carbon particles contained within the carbon plug (210), as described above. Upon actuation of the valve, carbon dioxide gas desorbs from the carbon, cooling the food or beverage in the container containing the HEU (200).

As shown in fig. 6, the top section (204) of the HEU (200) is shaped such that its skirt (216) fits outside the outer surface (218) of the HEU housing (202). The skirt (216) of the top section (204) includes an inner surface (214) that may define a plurality of grooves, shown as (220), (222), and (224). The inner surface (214) of the top section (204) receives a suitable metal-to-metal adhesive bonding material to permanently secure the top section (204) of the HEU (200) to the HEU housing (202). It should be understood that the inner surface of the top section (204) may be smooth or may define one or more grooves as desired. Various types of food grade adhesives may be used so long as they permanently bond the top (214) to the housing (202) of the HEU (200) and form a secure seal to retain pressurized carbon dioxide within the HEU. Examples of such adhesives that may be used may be cross-linking adhesives such as epoxy, acrylic, and the like.

The top section (204) may be machined from a suitable metal blank, such as stainless steel. Preferably, the top section (204) may be die cast from zinc or aluminum. Whether the top section (204) is machined or die cast, or formed by other methods, such as, for example, by eyelet stamping or forming or centrifugal casting, it has the required strength to withstand the pressure generated by the pressurized carbon dioxide and does not fail even under high temperature conditions.

As seen more clearly in fig. 7, the top section (204) is formed to provide a shoulder or stop (226) which is disposed on the inner surface (214) of the top section (204) and above the grooves (220), (222) and (224), if any. The shoulder (226) is configured to mate with an edge (207) of the housing (202) of the HEU (200). After the carbon plug (210) is positioned inside the casing (202), the inside of the top section (204) is applied with a suitable adhesive, and then the top section is slid into place outside the outer surface (218) of the casing (202) until its edge (207) engages the shoulder (226), whereupon the top section (204) is now in place. The top section (204) is then permanently positioned and held in place and bonded to the housing (202) as a result of the placement of the adhesive, rendering it impossible to remove. It is also appreciated that a seal, such as a weld (228), may be formed between the bottom edge (230) of the top section (204) and the outer surface (218) of the housing (202). The seal or weld (228) may address the problem of abrupt changes in container profile and thereby eliminate the possibility of trapped contaminants.

An open upper portion (208) of the top section (204) is formed to provide a hard crimp (232) that receives a crimped flange of the outer periphery of the mounting member of the valve as described above. The top section (204) of the HEU (202) is preferably constructed of die cast zinc or aluminum that is sufficiently strong so as not to be crushed or dislodged under the pressure created by the cooling medium, such as carbon dioxide gas adsorbed by the carbon plug (210).

By using a structure as shown and described above, a maximum amount of highly compacted carbon particles can be received within the HEU enclosure to maximize the amount of carbon dioxide adsorbed by the HEU. As is well known and described in the art, when the valve through which carbon dioxide is introduced into the carbon block (210) is actuated, the adsorbed carbon dioxide is then desorbed from the carbon particles and exits the HEU, which removes heat from the food or beverage around the outer surface (218) of the HEU, thus cooling the food or beverage to the desired result (amount) to make it more palatable. As described in us patent 6,105,384, which is incorporated herein by reference, a protective food-grade coating can be applied over the entire outer surface of the HEU to exclude any possibility of contaminating the food or beverage surrounding the HEU or altering its mouthfeel. The coating may be a food grade epoxy paint (epoxyacryl) having a thickness of between 4 and 10 microns.

As such, the HEU disclosed in this specification is constructed of a material with sufficient strength and is constructed to be effective and safe even under relatively high pressure conditions.

Claims (6)

1. A heat exchange unit for containing a pressurized medium for cooling a food or beverage placed in and surrounding a container in which the heat exchange unit is used, comprising:

a metal housing having an outer surface, a closed bottom, and an open upper end terminating in an edge;

a die-cast metal top section substantially thicker than said metal shell and having an opening defined by a solid curl and a skirt having an inner surface and a terminal end, the skirt being fitted over the open upper end of said metal shell and extending downwardly along the outer surface of said shell, the inner surface of said skirt having a shoulder;

said edge of said metal shell abutting said shoulder of said skirt inner surface when said top section is in place on said metal shell, whereby skirt inner surface overlaps said outer surface of said shell a substantial distance; and

a metal-to-metal adhesive disposed between the top section inner surface and the shell outer surface to permanently secure the metal top section to the metal shell;

wherein the mounting member is inserted into the opening, the mounting member is fixed to the strong crimp portion by a crimping operation, the valve assembly is fixed to the heat exchange unit, and the open upper end portion of the heat exchange unit and the can in which the heat exchange unit is installed are closed and sealed.

2. A heat exchange unit as defined in claim 1 further comprising compacted carbon particles received within said metal shell.

3. A heat exchange unit as defined in claim 2 wherein a valve assembly is used to inject a pressurized medium into said heat exchange unit for adsorption by said carbon particles and to desorb said pressurized medium for cooling said food or beverage.

4. A heat exchange unit as defined in claim 1 wherein said metal top section is die cast zinc.

5. A heat exchange unit as defined in claim 1 wherein the inner diameter of said skirt is substantially the same as the outer diameter of said metal shell and is sized to allow said skirt to slip fit outside said metal shell during assembly.

6. A heat exchange unit as defined in claim 2 wherein said pressurized medium is carbon dioxide.