WO2002088608A1

WO2002088608A1 - Method of manufacturing a multi-layered sorbent-driven self-cooling device

Info

Publication number: WO2002088608A1
Application number: PCT/US2001/050705
Authority: WO
Inventors: Douglas Smith; Kevin Roderick; Lyra Fiset
Original assignee: Thermal Product Developments, Inc.
Priority date: 2001-04-25
Filing date: 2001-10-16
Publication date: 2002-11-07
Also published as: JP2004525334A; CA2445525A1; JP3989011B2; IL158605A0

Abstract

A sorbent driven cooling device layered within a sealed and evacuated tray having either a symmetrical or asymmetrical layering sequence and which may be integrated within, a panel of a beverage container.

Description

METHOD OF MANUFACTURING A MULTI-LAYERED SORBENT-DRIVEN SEFL-COOLING DEVICE

BACKGROUND OF THE INVENTION

5

1. Field of the Invention

The present invention relates to the thermal chemical arts. More particularly to sorbent-driven cooling devices and their method of manufacture.

0 2. Discussion of the Related Art

Applicants' pending patent application Serial No. 09Λ691,473, filed on October 18, 2000 entitled "Evacuated Sorbent Assembly and Cooling Device," herein incorporated by reference, teaches a self-cooling device having a small volume relative to the quantity of liquid to be cooled. The cooling device is driven by the 5 absorption and absorption of a liquid refrigerant, such as water. Both the adsorbing material and the liquid are held in separated evacuated chambers with the liquid refrigerant chamber in thermal contact with the medium to be cooled. Upon communication between the two evacuated chambers the liquid refrigerant starts to vaporize. The latent heat of vaporization channels heat away from the medium, the 0 adsorption of the initial vapor drives the vaporization of more liquid refrigerant, thereby continuing to cool the medium.

Other self-cooling devices for the rapid chilling of beverages are found in U.S. Pat. No. 4,928,495 issued to Siegel, which teaches a two-chamber device which utilizes adsorption technologies. This patent describes a device in which a cooling 5 chamber is placed in the beverage to be cooled and a heat absorbing chamber is held remote from the beverage. The remote placement results from the need to manage thermal leakback from the heat-absorbing chamber. This heat management solution results in other obstacles associated with losses in efficiency of cooling because of the long vapor trails between the cooling and heating chambers. 0 Another cooling device, which exchanges the ambient heat from a beverage into an adsorbent, thereby resulting in a cooling of the beverage, is described in U.S. Pat. No. 6,151,911 issued to Dando. This patent describes a cylindrical member mounted within a beverage with a cooling portion at the bottom and a heat receiving portion, which may contain a phase change material, at its top. The device occupies a portion of the interior space of the container and manages the thermal leakback by remote placement of the heat-absorbing portion of the device from the cooling portion of the device. Boxes or flexible pouches for packaging and consuming food and beverages are well known in the art. In general, such packages may be separated into two categories. Those substantially rigid box-like structures including the "aseptic container" generally formed from a foldable blank which may be a multilayer laminate often a combination of rigid, semi-rigid and flexible materials. Flexible pouch containers serve a similar function to the aseptic type box container but remained distinctly more flexible, normally being comprised of only flexible materials.

SUMMARY OF THE INVENTION

Now in accordance with the inventive method there is taught a process for preparing a cooling device formed in a tray-like casing. In all embodiments, it is the evaporation of a liquid refrigerant and the sorption of the resulting refrigerant vapor onto a sorbent layer which drives the cooling process. In some embodiments, the cooling device is symmetrical with a cooling region on its top and bottom surfaces and an insulated heat absorbing central region. In other embodiments the cooling device is asymmetrical with a cooling region on its top or bottom surface and the insulated heat-absorbing region on the opposite surface.

In either the symmetrical or asymmetrical cooling devices, a sequenced layering of materials, sealed within a tray-like casing, under a vacuum, provides the cooling function of the device. Two basic configurations of materials are taught herein. A primary difference is the choice of either a wicking agent and thermal spacer or of an insulating material to wick the liquid refrigerant and insulate the sorbent layer from the outer cooling surface.

In some embodiments, the asymmetrical device is formed with a heat- removing material on the bottom, covered by a liquid barrier, followed by a sorbent layer (in thermal contact with the heat-removing material) and followed by the insulating material, which may be covered by a capillary membrane to direct the liquid refrigerant. To keep the liquid refrigerant remote from the insulation and sorbent, until cooling is desired, a rupturable bag encases the liquid refrigerant. After layering it is evacuated from the casing and the casing seal is sealed with a flexible cover.

In another embodiment the asymmetrical device is formed with a liquid refrigerant, covered by a rupturable bag containing refrigerant liquid followed by a layer of insulating material with a sorbent placed above the insulating material and covered with a liquid barrier. At the top of the casing is placed the heat removing material, which is sealed with the flexible cover.

In another asymmetrical embodiment, the layering sequence is to first place a heat-removing material on the bottom of the casing which is then covered by a liquid barrier, followed by a sorbent layer (in thermal contact with the heat removing material), followed by a thermal spacer, covered by a vapor permeable membrane, with a wicking material thereabove. The rupturable bag containing the refrigerant is positioned adjacent to the wicking material and the device is then sealed with a flexible cover. The above layering sequence may also be reversed with the liquid refrigerant at the bottom of the casing, or constructed to allow the wicking to direct a portion of the liquid refrigerant from the top of the device to the casing bottom.

A symmetrical device, utilizing the insulating material, may be constructed by duplicating the layers in a reversed order, either above or below the heat removing material.

The cooling device may be affixed to a beverage container or integrated into the beverage container.

Other features and advantages of the present invention will be set forth, in part, in the description which follows and the accompanying drawings, wherein the preferred embodiments of the present invention are described and shown, and in part will become apparent to those skilled in the art upon examination of the following detailed description taken in conjunction with the accompanying drawings, or may be learned by practice of the present invention. The advantages of the present invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appendent claims. DESCRIPTION OF THE DRAWINGS

FIG. 1 A is a partially cut-away elevational view of the cooling device in accordance with the invention.

FIGS. IB- IF are plan views of alternate shapes for the cooling devices. FIG. 1G-1K are cross-sectional views of alternate shapes for the cooling devices.

FIG 2 A is a cross-sectional view of a cooling device in accordance with the invention.

FIG. 2B is a cross-sectional view of a first alternate embodiment of the cooling device.

FIG. 2C is a cross-sectional view of a second alternate embodiment of the cooling device.

FIG. 2D is a cross-sectional view of a third alternate embodiment of the cooling device. FIG. 3 A is a cross-sectional view of a fourth alternate embodiment of the cooling device.

FIG. 3B is a cross-sectional view of a fifth alternate embodiment of the cooling device prior to the completion of its assembly.

FIG. 3C is a cross-sectional view of the embodiment of FIG. 3B fully assembled.

FIG. 4 A is a component view of the preferred embodiment of the flexible self- cooling beverage pouch.

FIG. 4B is a component view of a first alternate embodiment of the flexible self-cooling beverage pouch. FIG. 4C is a cross-sectional view of one embodiment of a flexible self-cooling beverage pouch.

FIG. 4D is a cross-sectional view of another embodiment of a flexible self- cooling beverage pouch.

FIG. 5 A is a perspective view of a self-cooling box container. FIG. 5B is a first alternate embodiment of the self-cooling box container.

FIG. 5C is a second alternate embodiment of the self-cooling box container. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.

Certain terminology will be used in the following specification for convenience in reference only and will not be limiting. For example, the word "absorption" refers to the occurrence of a substance (e.g., water vapor) penetrating the inner structure of another (the absorbent). Also, the word "adsorption" refers to the occurrence of a substance (e.g., water vapor) being attracted and held onto the surface of another (the adsorbent). The words "absorption" and "adsorption" include derivatives thereof. The word "sorbent" refers to a material that is either an absorbent and/or an adsorbent.

As shown in FIG. 1 A, cooling device 10 is constructed with a tray-like casing 11, having sidewalls 18 (two shown) and a bottom 16. The casing is sealed with a cover 12. The shape, dimensions and configuration of the casing is a function of the materials used, the degree of cooling desired, the rate of cooling desired, the shape, size, and volume of the material to be cooled, and the nature of the material to be cooled. In the embodiment shown in FIG. 1 A the casing has substantially rectangular cross section.

As seen in FIGS. IB- IF, other casing configurations which may be useful include casings 11 that have square, polygonal, circular, semi-circular or irregular cross sections. The casings can have a flat bottom 16 as shown in FIG. 1 A or, as shown FIGS. 1G and 1H, have one or more bottom indentations 13. Bottom indentations 13 act to partition at least a potion of the casing's interior into at least a first chamber 11a and a second chamber l ib (FIG. 1G) and in some embodiments a third chamber l ie (FIG. 1H). Additionally, as shown in FIGS. U and IK, a portion 17 of the bottom 16 can protrude downward from the flat bottom surface. An edge 28 for sealing the cover 12 projects outward from the top of the sidewall(s). A stepped region 14, as shown in FIGS. II and K, may be formed in the casing 11 projecting outwardly from the portion of the top of a sidewall 18. Raised spikes 15 projecting into the interior of the casing can be formed on the substantially flat bottom 16 (FIG. 11), within the stepped region 14 (FIGS. II and IK) or at the bottom 16 of a protrusion 17 (FIGS. U and IK).

The above configuration examples for the casing 11 are not intended to be an exhaustive list, and the appropriate combination of indentations 13, stepped regions 14, bottom protrusions 17 and/or raised spikes 15 is dependant on a variety of factors including, but not limited to, the intended use of the device, the required cooling performance of the device as well as the selection and quantities of material layers 10.

As shown in FIG 2A, materials are layered within the casing 11 to create a cooling device. The first layer added to the bottom 16 of the casing 11 is a layer of heat-removing material 21. When absorbing heat during operation of the cooling device 10, the heat- removing material 21 may generate by-products such as water, aqueous salt solutions, and organics. Therefore, depending on the particular heat-removing material utilized, it is normally desirable to include a heat-conductive liquid barrier 22. The heat- conductive liquid barrier 22 is added on top of the heat-removing material 21. A sorbent layer 23 follows on top of the liquid barrier 22. The sorbent layer 23, through the interposed liquid barrier 22, is in thermal contact with the heat-removing material 21.

A layer of insulating material 24, having a hydrophobic surface 24a and a hydrophilic surface 24b is then added, so that the hydrophilic surface is in direct contact with the sorbent layer 23.

Finally, a predetermined amount of liquid refrigerant 25 contained within a rupturable bag 26 is added above the insulation 24 so that it is adjacent the hydrophilic surface 24b, and so that a portion of the bag extends into the interior of the stepped region 14. The filled casing is placed in a vacuum, the air evacuated, and the cover 12 sealed over the top edge 28 of the casing.

To release the liquid refrigerant 25 and activate the device, an operator applies pressure along the line of arrows 1000 and 1001 causing the spike 15 to rupture the bag 26 thereby releasing the liquid refrigerant and initiating the cooling action. Because the bag containing the liquid refrigerant is adjacent the cover 12, in this embodiment, the active cooling region of the device is the cover's exterior surface.

In the embodiment shown in FIG. 2B, the layering sequence is reversed thereby forming a cooling device in which the active cooling region of the device is the exterior surface of the bottom of the casing 16. The casing 11 has a bottom protrusion 17 and a raised spike 15. To release the liquid refrigerant 25 and activate the device, an operator applies pressure along the line of arrows 1002 and 1003 driving the spike 15 into the bag 26 thereby releasing the liquid refrigerant 25 and initiating the cooling action. The multi-chambered casing 11 shown in FIGS. 2C is designed to provide a device less prone to accidental initiation of the cooling function. The liquid refrigerant 25 within the bag 26 is placed into one chamber l ib with all the other materials layered in the second chamber 11a.

In the embodiment shown in FIG. 2, a layer of heat-removing material is added to the bottom 16 of the casing 11 , within the chamber 1 a, then covered by the liquid barrier 22, followed by the sorbent layer 23 which is in thermal contact with the heat-removing material 21. A layer of the insulating material 24, with its hydrophobic surface 24a in direct contact with the sorbent layer 23, is then added. The second chamber l ib receives the predetermined amount of liquid refrigerant 25 within the rupturable bag 26. A capillary membrane 29, providing fluid communication between the hydrophilic surface 24b of the insulating material 24 and the liquid refrigerant 25, is then added. The filled casing 11 is placed in a vacuum, the air evacuated, and a flexible cover 12 is sealed over the top edge 28 of the casing 11. To release the liquid refrigerant 25 and activate the device, an operator applies pressure along the line of arrows 1004 and 1005 breaking the rupturable bag 26. Once broken, the bag releases the refrigerant liquid which is transported via the capillary membrane 29 to the hydrophilic region 24b of the insulating material 24.

A symmetrical cooling device, i.e., a device having active cooling regions at both its top and bottom is shown in FIG. 2D. A first measure of liquid refrigerant 25 within a first rupturable bag 26 is added to the bottom 16 of the casing 11, followed by a first layer of insulating material 24, with its hydrophilic surface 24b against the first bag 26, and then followed by a first sorbent layer 23. A first liquid barrier 22 covers the first sorbent layer 23, followed by and the heat-removing material 21, in thermal contact with the first sorbent layer 23. A second liquid barrier 22* is then added above the heat-removing material 21, followed by a second sorbent layer 23' which is also in thermal contact with the heat-removing material 21. A second layer of insulating material 24', with its hydrophobic region 24a' in direct contact with the second sorbent layer 23', is then added. A second measure of liquid refrigerant 25' within a rupturable bag 26' is added above the second sorbent layer 23'. The filled containment casing 11 is then placed in a vacuum, the air evacuated, and a flexible cover 27 is sealed over the top edge 28 of the containment casing. To release the liquid refrigerants 25 and 25' and activate the device, an operator applies pressure along the line of arrows 1000 and 1001 and arrows 1002 and 1003 breaking the rupturable membranes 26 and 26' thereby supplying liquid refrigerant 25 and 25' to the hydrophilic surfaces 24b and 24b' of the insulating material 24 and 24'.

Other symmetrical and asymmetrical cooling devices are constructed by altering the materials. Shown in FIGS. 3A-3C are cooling devices constructed without the insulating material 24 or the capillary membrane 29. In these embodiments, a thermal spacer 30 and vapor permeable membrane 31 combine with a wicking material 32 to transport the liquid vapor to the sorbent layer 23 and control the thermal leakback. When wicking material 32 is incorporated into the cooling device it acts to draw liquid refrigerant 25 from the ruptured bag 26 and to retain the liquid refrigerant 25 for subsequent vaporization and adsorption by the sorbent layer 23. In addition, the wicking material 32 absorbs any vaporized liquid refrigerant that re-condenses before reaching the sorbent layer 23.

As there can be large temperature differences between the wicking material 32 and the sorbent layer 32, in some embodiments the thermal spacer 30 is interposed between the sorbent layer 23 and the vapor-permeable membrane 31 or between the sorbent layer 23 and the wicking material 32. The thermal spacer 30 is utilized to insulate heat generated by the sorbent layer 23.

A layering sequence of such an asymmetrical cooling device is shown in FIG. 3 A, which begins by adding to the bottom 16 of the casing 11 a layer of the heat- removing material 21. The liquid barrier 22 is added above the heat-removing material 21 and the sorbent layer 23 in thermal contact with the heat removing material 21 follows the liquid barrier 22. A thermal spacer is added above the sorbent layer 23, which is covered by a vapor permeable membrane 31 and a wicking material 32 rests up against the vapor permeable membrane 31. Finally, a predetermined amount of liquid refrigerant 25 within a rupturable bag 26 is added on top of the wicking material 32 and extending into the stepped region 14. The filled casing 11 is then placed in a vacuum, the air evacuated, and a flexible cover 12 is sealed over the top edge 28 of the casing 11. The stepped region 14 of the casing 11 provides an easy to locate region to which an operator can apply pressure along the line of arrows 1000 and 1001 thereby causing spike 15 to break the rupturable bag 26 and initiate the cooling action.

The symmetrical device shown in FIGS 3B and 3C, is formed by applying sufficient wicking material 32 to the interior of the casing 11 to extend from the bottom 20 of the casing 11, up one of the sidewalls 18 and above the top edge 28. A layer of vapor permeable membrane 31 having opposing ends 31a and 31 b is then added on top and the wicking material 32 with the opposing ends extending along opposing sidewalls 18, the casing 11 and above the top edge 28.

Once the wicking material and vapor permeable membrane have been applied, a first thermal spacer 30 is placed above the portion of the vapor permeable membrane 31 covering the bottom 20 of the casing 11 , followed by the first sorbent layer 23, covered with the first liquid barrier 22, followed by the heat-removing material 21. The second liquid barrier 22' is then added above the heat-removing material 21 and followed by the second sorbent layer 23' and a second thermal spacer 30'. Prior to adding the liquid refrigerant 25, the first end 31a of the vapor permeable membrane 31 is folded along the lines of arrow 1006 so that the vapor permeable membrane covers the second thermal spacer 30'. The second end 31b of the vapor permeable membrane 31 then folded along the line of arrow 1007 and affixed over the first end 31a thereby sealing of the second thermal spacer 30'. The wicking material 32 is then folded over the vapor permeable membrane 31 along the line of arrow 1008 and finally a predetermined amount of liquid refrigerant 25 within a rupturable bag 26 is added above the wicking material 32. The filled casing casing 11 is then placed in a vacuum, the air evacuated, and the flexible cover 12 is sealed over the top edge 28.

To release the liquid refrigerant 25 and activate the device, an operator applies pressure along the line of arrows 1000 and 1001, breaking the rupturable bag 26 supplying liquid refrigerant 25 to the wicking material 32 which transports the liquid refrigerant to the top and bottom 20 of the containment casing 11. Liquid vapor migrates across the vapor permeable membrane 31 through the first and second thermal spacers 30 and 30' and into the first and second sorbent layers 23 and 23'. The casing 11 and the cover 12 are constructed from a material that is impervious to air and moisture so as to provide the cooling device 10 with a suitable shelf-life (to allow for several years of storage/inactivation prior to use). Useful materials have an oxygen transmission rate (OTR) preferably less than about 1 cm³ /m²/day, more preferably less than 0.1 cm /m /day, and most preferably less than 0.01 cm³/m²/day. The vapor transmission rate of useful materials is preferably less than about 2 g/m /day, more preferably less than 1 g/m /day, and most preferably less than about 0.1 g/m /day.

Suitable materials for the casing include thermoplastic materials. Suitable materials for the cover 12 include a metallicized plastic laminate or a metal foil plastic laminate. Preferred materials for the cover include flexible films such as those produced by the Rexam Corporation located in Bedford Park, Illinois, and Toyo Aluminum located in Osaka, Japan.

The sorbent layer 23 preferably is formed of an absorbent material dispersed on, impregnated in, affixed to, or otherwise combined with a porous support material. The porous support material preferably has a high pore volume, and therefore a high surface area, to accommodate the absorption of large amounts of liquid refrigerant 25, in vapor form, by the sorbent. The pore volume is expressed in units of volume per unit mass. The porous support material has a pore volume of at least about 0.8 cc/g, more preferably at least about 1 cc/g, and even more preferably at least about 1.5 cc/g. In order to accommodate high absorption levels of liquid refrigerant 25, it is also important to control the average pore diameter and pore size distribution of the porous support material. The average pore diameter is preferably at least about 1 nanometer, and typically in the range from about 1 to about 20 nanometers. The average pore diameter distribution is such that there are very few pores having a diameter of less than about 0.5 nanometers. The porous support material can be selected from virtually any material having the above-identified properties. Preferred materials for the porous support material include activated carbon and silica.

The porous support material can come in a variety of shapes and sizes selected for a particular application. For example, in some embodiments, the porous support material is comprised of small activated carbon pellets having a size in the range of from about 0.5 to 2 millimeters. In alternative embodiments, the porous support material is silica pellets having a size from about 0.25 to 0.5 millimeters. The size of the pellets can be selected to influence the rate at which the vapor from the liquid refrigerant 16 is absorbed. Larger pellets absorb liquid refrigerant vapor at a slower rate due to increased path length.

It is preferred that the sorbent material have a pore volume that is at least about 50 percent of the pore volume of the porous support material, and even more preferably at least about 66 percent of the pore volume of the porous support material. That is, it is preferred that if the pore volume of the porous support material is about 1.5 cc/g, then the pore volume of the absorbent material is preferably no less than about 0.75 cc/g, more preferably no less than about 1.0 cc/g.

When the liquid refrigerant 25 is water, the absorbent material is preferably capable of absorbing at least about 100 percent of its weight in water, more preferably at least about 150 percent of its weight in water, and even more preferably at least about 200 percent of its weight in water. The amount of water that can be absorbed will also be influenced by the relative humidity and temperature.

Any suitable absorbent material can be used. Representative absorbent materials include salts such as calcium chloride, lithium chloride, lithium bromide, magnesium chloride, calcium nitrate, and potassium fluoride. Other suitable absorbent materials include phosphorous pentoxide, magnesium perchlorate, barium oxide, calcium oxide, calcium sulfate, aluminum oxide, calcium bromide, barium perchlorate, and copper sulfate, zeolite 13x, zeolite 5a, silicalite, silica gel, alumina, carbon, modified carbons and the like. The absorbent material may comprise combinations of two or more of these materials.

The heat-removing material 21 is one of three types: (1) a material that undergoes a change of phase when heat is applied (phase-change material); (2) a material that has a heat capacity greater than the sorbent layer 23; or (3) a material that undergoes an endothermic reaction when brought in contact with a vaporized liquid refrigerant 25. It will be understood by the skilled artisan that the heat- removing material, for use in a particular application may vary depending on the sorbent utilized, the thermal insulation, if any, between the phase-change material, the liquid refrigerant, and the desired cooling rate. Suitable heat-removing materials 21 include paraffin, naphthalene sulphur, hydrated calcium chloride, bromocamphor, cetyl alcohol, cyanamide, eleudic acid, lauric acid, hydrated calcium silicate, sodium thiosulfate pentahydrate, disodium phosphate, hydrated sodium carbonate, hydrated calcium nitrate, neopentyl glycol, hydrated inorganic salts including Glauber's salt, inorganic salts encapsulated in paraffin, hydrated potassium and sodium sulfate, and hydrated sodium and magnesium acetate. The preferred heat-removing material is an inorganic salt that has been melted and re-solidified to form a monolith (thereby reducing the volume of the heat-removing material by approximately 30%). The heat-removing material 21 removes some of the heat from the sorbent layer 23 simply through the storage of sensible heat, because the heat-removing material heats up as the sorbent sections heat up, thereby removing heat from the sorbent sections. However, the most effective heat-removing material typically undergoes a change of phase. A large quantity of heat is absorbed in connection with a phase change (i.e., change from a solid phase to a liquid phase, change from a solid phase to part solid phase and part liquid phase, or change from a liquid phase to a vapor phase). During the phase change, there is typically little change in the temperature of the heat-removing material, despite the relatively substantial amount of heat absorbed to effect the change. Another requirement of a phase-change heat-removing material 21 is that it change phase at a temperature greater than the expected ambient temperature of the material to be cooled, but less than the temperature achieved by the sorbent layer 23 upon absorption of a substantial fraction (i.e., one-third or one-quarter) of the liquid refrigerant 75. When the current invention is placed in, attached to, or otherwise integrated into, a container, the phase change should take place at a temperature above about 30°C, preferably above about 35°C but preferably below about 70°C, and most preferably below about 60°C.

The insulating material 24 is chosen to inhibit thermal leakback from the sorbent sections 28 and 30 to the exterior of the device. Typically, the insulating material has thermal conductivity limits less than 0.05 W/mK, preferably less than about 0.035 W/mK, and most preferably, less than about 0.025 W/mK. Preferably, the insulating material 71 has a collapse strength sufficient to resist about one bar uniaxial load, and limit the shrinkage, due to evacuation, to less than about 20%, more preferably less than about 5%, and most preferably less than about 2%. In some embodiments, an anisotropic insulating material containing both a hydrophilic region 72 and a hydrophobic region 73 is preferred. Such an insulating material inhibits the passage of liquid refrigerant 16 into the sorbent sections 28 and 30, yet allows the vapor of the liquid refrigerant to pass into the sorbent sections 28 and 30. The hydrophilic region 72 of the insulating material has pores with a relatively large diameter, not less than 10 mm in diameter, on average. The large pores of the hydrophilic region 72 encourage the rapid flow of liquid refrigerant 16 into the material. The hydrophobic region 73 has pores of a relatively small diameter, typically less than about 2 mm in diameter, so that the un- vaporized liquid refrigerant 16 is inhibited from passing into the sorbent section 28 and 30, but rather only the vapor from the liquid refrigerant 16 is directed into the sorbent section 28 and 30.

The ratio of the thickness of the hydrophobic region 73 to hydrophilic region

72 is a function of the choice of materials used to form those regions, the quantity of liquid refrigerant 16 in the device, and the desired performance criteria of the device.

The insulating material 73 can be formed by laminating a hydrophilic material such as cellulose, paper, non- woven or woven cloth formed from fibers of glass, plastic, ceramic or cellulose, to a hydrophobic material. The hydrophobic material can be made by modifying a hydrophilic material with a hydrophobic agent, such as by impregnating a hydrophilic material with wax or adding a hexamethyldisiliazane or a flourinated reactive group to the hydrophilic material.

Alternatively, the insulating material can be formed by surface modification, whereby a sheet of material (either hydrophilic or hydrophobic) is modified to change the surface on one side. In general, the surface of one side of a hydrophobic material can be made hydrophilic by exposure to thermal or plasma treatments or by impregnation with surfactants. The surface of a hydrophilic material can be made hydrophobic by treatment with hydrophobing agents or impregnation of wax-like material.

The liquid barrier may be constructed of any suitable material, such as polyethylene or polypropylene film. When the liquid refrigerant is water, suitable wicking materials 32 include hydrophilic materials such as microporous metals, porous plastics (polyethylene, polypropylene), cellulose products, sintered heat pipe material, or glass paper, and the like.

Only the amount of wicking material 32 required to draw all of the liquid refrigerant 25 to be adsorbed need be incorporated into the device. The wicking material has a pore size sufficient to permit capillary action (the drawing of all the liquid refrigerant 25 to occur within 60 seconds, and most preferably, within 10 seconds after actuation). Since the temperature between the wicking material 32 and sorbent layer 23 can vary from 5°C to 150°C, the thermal spacer 30 has a thermal resistance (thermal conductivity at package conditions divided by thickness) preferably less than 100 W/m K, more preferably less than 50 W/m K, and most preferably less than 20 W/m²K. The materials utilized for the thermal spacer 30 can be selected from a range of materials known to the art that provide sufficient vapor permeability such as fiberglass, plastic fibers, and plastic foams.

In some embodiments, the rupturable membrane 26 is a plastic, typically polyethylene, that is filled and heat sealed along its edges 62 enclosing the liquid refrigerant 25. The liquid refrigerant 25 should have a high vapor pressure at ambient temperature so that a reduction of pressure will produce a high vapor production rate. In addition, the liquid refrigerant has a high heat of vaporization. The vapor pressure of the liquid refrigerant at 20°C is typically at least about 9 mm Hg, preferably at least about 15 or 20 mm Hg. Suitable liquid refrigerants include various alcohols, such as methyl alcohol or ethyl alcohol; ketones or aldehydes such as acetone and acetaldehyde; and hydrofluorocarbons such as C318, 114, 21, 11, 114B2, 113, 112, 134A, 141B, and 245FA. The preferred liquid refrigerant is water because it is plentiful and does not pose any environmental problems while providing the desired cooling characteristics. In some embodiments, the liquid refrigerant 25 is mixed with an effective quantity of a miscible nucleating agent (or a partial miscible nucleating agent) having a greater vapor pressure than the liquid refrigerant to promote ebullition so that the liquid refrigerant evaporates even more quickly and smoothly, while preventing the liquid refrigerant from super-cooling and thereby decreasing the adsorption rate in the sorbent layer 23. Suitable nucleating agents include ethyl alcohol, acetone, methyl alcohol, isopropyl alcohol and isobutyl alcohol, all of which are miscible with water. For example, a combination of a nucleating agent with a compatible liquid might be a combination of 5% ethyl alcohol in water or 5% acetone in methyl alcohol. The nucleating agent preferably has a vapor pressure at 25°C of at least about 25 mm Hg, and, more preferably, at least about 35 mm Hg. Alternatively, a solid nucleating agent may be used, such as a conventional boiling stone used in chemical laboratory applications.

FIGS. 4 A through 4H illustrate flexible pouch containers which may contain a beverage, with a cooling device attached to, or integrated into, one or more side walls. FIG. 4 A shows the panels used to form a juice pouch without a bottom, and FIG. 4B shows the components to construct a juice pouch with a substantially flat bottom. In both FIGS. 4 A and 4B, the side panels and bottom panel are heat sealed at the edges to form the pouch containers (FIGS. 4C and 4D). FIG. 4C illustrates a partially cutaway side view of a flexible pouch beverage container with a single cooling device according to FIG. 2A, integrated into a side panel. FIG. 4D illustrates a flexible pouch beverage container with multiple cooling devices integrated into the side panels. In all embodiments shown with cooling devices integrated into flexible beverage containers, the cover 12 of the casing 11 is extended to form all, or a portion, of the panel being used to construct the beverage container.

In FIGS. 4E and 4G are shown alternate embodiments of the flexible pouch beverage containers with integrated cooling devices. In FIG. 4C a casing such as that shown in FIG. 1H is integrated into the wall panels by the cover 12. The edges of the cover which form the side panel may be heat sealed to another side panel and the bottom panel is also heat sealed to the bottom edges forming the beverage containers shown in FIGS. 4C and 4D.

In FIGS. 4F and 4G the cooling device is in the form of the casing shown in FIG. 1H which provides single actuation for both cooling devices 11a from one common liquid reservoir l ib. The liquid reservoir 1 lb may be positioned on the side of the beverage container (FIG. 4H) on the top FIG. 4F.

FIGS. 5 A through 5D show a box-type beverage container such as an asepic box folded from a single blank to which one or more cooling devices may be attached. In FIG. 5A a cooling device is attached to opposite side walls with each cooling device with its own actuator, in a casing akin to that shown in FIG. 1G. In FIG. 5B and 5D there is a common liquid reservoir l ib, thereby both devices may be initiated at once, one on each side wall in a casing configuration similar to that of FIG. 1H. Also a weakened region may be formed in the box to allow for a straw to pierce there through.

Embodiments of the cooling device decrease the temperature of a beverage in a beverage container by at least about 12 °C and in some embodiments at least 15 °C or even 20 °C after actuation. In these embodiments, the liquid refrigerant reservoir contains less than 1.5 grams of liquid refrigerant per fluid ounce of beverage in the container. In some embodiments, the refrigerant liquid is water. Also, in some embodiments, the sorbent section has a mass of less than 3 grams of sorbent per fluid ounce of beverage. Depending upon the embodiment, the cooling device may decrease the beverage temperature in 10 minutes, or only 5 minutes, or even only 3 minutes. In some embodiments, the sorbent section occupies less than 5 cubic centimeters per fluid ounce of beverage, and the cooling device occupies less than 0.5 fluid ounces per fluid ounce of a beverage in a beverage container.

With such possibilities in mind, the invention is defined with reference to the following claims.

Claims

We claim: 1. A method of manufacturing a self-cooling device comprising; selecting an waterproof open container; placing a layer of heat removing material in the bottom of the container; placing a liquid barrier membrane above the heat removing material; placing a sorbent layer, containing a sorbent which acts as a refrigerant above the liquid barrier, and in thermal contact with the heat removing material; placing an insulation layer above and in direct contact with the sorbent layer; placing a rupturable liquid barrier above the insulation layer; placing a measure of liquid refrigerant above the rupturable liquid barrier; placing the container and its contents under a vacuum; and, sealing the container, with a flexible waterproof cover, while under the vacuum, with a waterproof cover.

2. The method of claim 1 wherein the insulation layer is constructed of an anisotropic material with a hydrophilic side adjacent to a hydrophobic side, whereby the hydrophobic side is in contact with the sorbent layer

3. The method of claim 1 wherein the insulation is a thermal spacer and further comprising; placing a vapor permeable membrane above the thermal spacer; and, placing a wicking layer above the vapor permeable membrane and beneath the rupturable liquid barrier.

4. A method of manufacturing a self-cooling device comprising; selecting a waterproof open container; placing a measure of liquid refrigerant in the bottom of the container; placing a rupturable liquid barrier above the measure of water; placing an insulation layer above the rupturable liquid barrier; placing a sorbent layer, containing a sorbent which acts as a refrigerant, above and in contact with the insulation layer; placing a liquid barrier membrane, above the sorbent layer; placing a layer of heat removing material, in thermal contact with the sorbent layer, above the liquid barrier membrane; placing the container and its contents under a vacuum; and, sealing the container, with a flexible waterproof cover, while under the vacuum, with a waterproof cover.

5. The method of claim 4 wherein the insulation layer is constructed of an anisotropic material with a hydrophilic side adjacent to a hydrophobic side, whereby the hydrophobic side is in contact with the sorbent layer

6. The method of claim 5 wherein the insulation is a thermal spacer and further comprising; placing a vapor permeable membrane below the thermal spacer; and, placing a wicking layer below the vapor permeable membrane and above the rupturable liquid barrier.

7. A method of manufacturing a self-cooling device comprising; selecting a waterproof open container; placing a first measure of liquid refrigerant in the bottom of the container; placing a first rupturable liquid barrier above the first measure of water; placing a first insulation layer above the first rupturable liquid barrier; placing a first sorbent layer, containing a sorbent which acts as a refrigerant, above and in contact with the first insulation layer; placing a first liquid barrier membrane, above the first sorbent layer; placing a layer of heat removing material, in thermal contact with the first sorbent layer, above the first liquid barrier membrane; placing a second liquid barrier membrane above the heat removing material; placing a second sorbent layer above the liquid barrier, and in thermal contact with the heat removing material; placing a second insulation layer above and in direct contact with the second sorbent layer; placing a second rupturable liquid barrier above the second insulation layer; placing a second measure of liquid refrigerant above the second rupturable liquid barrier; placing the container and its contents under a vacuum; and, sealing the container, with a flexible waterproof cover, while under the vacuum, with a waterproof cover.

8. The method of claim 7 wherein the first and second insulation layers are each constructed of an anisotropic material with a hydrophilic side adjacent to a hydrophobic side, whereby the hydrophobic sides are each in contact with the adjacent first or second sorbent layer.

9. The method of claim 7 wherein the first and second insulations are each thermal spacers and further comprising; placing a first vapor permeable membrane above the first insulation layer ; placing a second vapor permeable membrane below the second insulation layer ; placing a first wicking layer above the first vapor permeable membrane and beneath the first rupturable liquid barrier; and placing a second wicking layer below the second vapor permeable membrane and above the second rupturable liquid barrier.

10. A method of manufacturing a self-cooling device comprising; selecting an open container partitioned into a first and second chamber that are adapted to communicate above the partition; placing a measure of liquid refrigerant within a rupturable liquid barrier within the first chamber; placing a layer of heat removing material in the bottom of the second chamber; placing a liquid barrier membrane above the heat removing material; placing a sorbent layer, containing a sorbent which acts as a refrigerant above the second liquid barrier, and in thermal contact with the heat removing material; placing an anisotropic insulation layer above and in direct contact with the sorbent layer; placing a capillary membrane layer above the anisotropic insulation layer and the liquid refrigerant within the rupturable liquid barrier; placing the open container and its contents under a vacuum; and sealing the open container with a flexible waterproof cover, while under the vacuum, with a waterproof cover.

11. A method of manufacturing a self-cooling device comprising; selecting an open container portioned into a front , middle and end chamber that are adapted to communicate above the partition; placing an open rupturable liquid container within the middle chamber; placing a layer of heat removing material in the bottom of the front and the end chambers; placing a layer of heat removing material in the bottom of each chamber; placing a liquid barrier membrane above each of the heat removing materials; placing a sorbent layer, in thermal contact with the adjacent heat removing material, containing a sorbent which acts as a refrigerant above each liquid barrier; placing an anisotropic insulation layer above and in direct contact with each sorbent layer; placing at least one capillary membrane above anisotropic insulation layers and the liquid refrigerant within the rupturable liquid barrier; placing the open container and its contents under a vacuum; and sealing the open container with a flexible waterproof cover, while under the vacuum, with a waterproof cover.

12. A method of manufacturing a self-cooling device comprising; selecting an open container partitioned into a first and second chamber that are adapted to communicate above the partition; placing a measure of liquid refrigerant within a rupturable liquid barrier within the first chamber; placing a wicking layer at the bottom of the second chamber and extending it upward and beyond the top of the container; placing a vapor permeable membrane above the wicking layer and extending it upward and beyond the top of the container; placing a first thermal spacer above the portion of the vapor permeable membrane adjacent to the bottom of the casing; placing a fist sorbent layer, containing a sorbent which acts as a refrigerant, above and in contact with the thermal spacer; placing a first liquid barrier membrane, above the first sorbent layer; placing a layer of heat removing material, in thermal contact with the sorbent layer, above the first liquid barrier membrane; placing a second liquid barrier membrane, above the heat removing material; placing a second sorbent layer, in thermal contact with the heat removing material above the second liquid barrier; placing a second thermal spacer above the second sorbent layer; covering and sealing off the top of the second thermal spacer by folding over the extended portion of the vapor permeable membrane; placing the extended portion of the wicking material over the folded over vapor permeable membrane; placing a measure of liquid refrigerant within a rupturable liquid barrier above the wicking material; placing the open container and its contents under a vacuum; and, sealing the open container with a flexible waterproof cover, while under the vacuum, with a waterproof cover.

13. A method of manufacturing a self-cooling device comprising; selecting an open container portioned into a first and second chamber that are adapted to communicate above the partition; placing an open rupturable liquid container within the first chamber; placing a layer of heat removing material in the bottom of the second chamber; placing a liquid barrier membrane above the heat removing material; placing a sorbent layer, containing a sorbent which acts as a refrigerant above the liquid barrier, and in thermal contact with the heat removing material; placing a thermal spacer above and in direct contact with the sorbent layer; placing a vapor permeable membrane above the thermal spacer; placing a wicking layer above the vapor permeable membrane and the second chamber ; placing the open container and its contents under a vacuum; and sealing the open container with a flexible waterproof cover, while under the vacuum, with a waterproof cover.

14. A method of manufacturing a self-cooling device comprising; selecting an open container portioned into a front , middle and end chamber that are adapted to communicate above the partition; placing an open rupturable liquid container within the middle chamber; placing a layer of heat removing material in the bottom of the front and the end chambers; placing a liquid barrier membrane above each of the heat removing materials; placing a sorbent layer, in thermal contact with the adjacent heat removing material, containing a sorbent which acts as a refrigerant above each liquid barrier; placing a thermal spacer above and in direct contact with each sorbent layer; placing a vapor permeable membrane above each thermal spacer; placing at least one layer of wicking material above the vapor permeable membranes and the middle chamber; placing the open container and its contents under a vacuum; and sealing the open container with a flexible waterproof cover, while under the vacuum, with a waterproof cover.

15. The method of claim 1, 10, or 13 wherein the flexible cover is the shape of a first side panel, is heat sealable and has a plastic lined outer surface; and further comprising; heat sealing the side edges the side panel to the corresponding heat sealable, side edges of a side panel thereby forming a pouch with an open top.

16. The method of claim 15 further comprising heat sealing a plastic lined bottom panel between the bottom edges of the first and second side panels; thereby forming a pouch with an open top and a base.

17. The method of claim 15 further comprising; adding a measure of liquid through the open top into the pouch; and sealing the open top of the pouch.

18. The method of claim 15 wherein a weak region is formed in the first or second side wall of the pouch, whereby a sealed and filled pouch may be pierced with a plastic straw.

19. The method of claim 15 wherein a weak region is formed near the top of the pouch whereby the top of the sealed pouch may be pulled apart to allow the liquid therein to be poured or consumed.

20. The method of claim 15 wherein the second side panel is substantially identical to the first side panel, thereby providing a second cooling device as part of the pouch.

21. The method of claim 16 wherein the second side panel is substantially identical to the first side panel, thereby providing a second cooling device as part of the pouch.