HK1079275A - Pervaporatively cooled containers - Google Patents

Description

Pervaporation cooling container

Technical Field

The present invention relates to a container device or closure for cooling liquids by means of pervaporation and a method for constructing such a container and closure.

Background

The houses and evaporative cooling of water originated in ancient egypt later propagated eastward through the middle east and irak to the north of the indian branch, westward across north africa to the south of spain and other areas subject to hot and dry climate. In the early days of this process unglazed crockery for holding water was used for centuries, with the added benefit of cooling the liquid water by absorbing and wicking moisture to the outer surface of the ceramic and then evaporating the moisture from its surface. Unfortunately, however, direct evaporation from the ceramic outer surface eventually leads to scale formation and reduced cooling effect due to reduced permeability and reduced evaporation pressure of the liquid as minerals accumulate on the surface.

Other methods based on a reduction in the amount of heat transfer from the environment to the liquid have been used. The methods used include vacuum and air gap thermos bottles and foam insulation sleeves. Other devices have been used that use ice, chilled cold parts or sticks to counteract the heat of the surrounding environment and return the liquid in the container to ambient temperature. In all these cases, the system must be constructed so that the liquid contents, the separate chambers and/or the housing of the bottle are cooled, which, in addition to the reduction of the liquid volume in the container, has the problem of excessive weight. In all of these processes, the temperature of the liquid will equilibrate and eventually return to ambient temperature.

Pervaporation (PV) is defined as a combination of vapor permeation and evaporation of a substrate (matrix). Since 1987, membrane pervaporation has gained wide acceptance in the Chemical industry for the separation and recovery of liquid mixtures (Chemical Engineering Progress, 7 months 1992, pages 45-52). The technique is characterized by the introduction of a barrier layer matrix between the liquid and gas phases. The liquid directly contacts one side of the substrate. Vapor mass is selectively transported to the gas side of the substrate, resulting in loss of liquid or loss of selected volatile liquid components and loss of latent heat of vaporization. This process is called pervaporation because it is a special combination of vapor "permeation" through a porous matrix and "evaporation" from the liquid phase to the gas phase. Without the heat added to the liquid, the temperature drops due to latent heat of evaporation until the temperature stops dropping when the heat absorbed from the environment equals the latent heat lost due to evaporation of the liquid at the surface or within the pores of the substrate, which reaches temperature equilibrium.

Us patent 5,946,931 describes the use of an evaporatively cooled PTFE membrane device that utilizes laminar fluid flow over the membrane to cool the device or environment to which it is attached. Us patent No. 4,824,741 describes the use of a pervaporatively cooled matrix to cool the surface of an electrochemical cell plate. The wet plate can be made of uncatalyzed PTFE-bonded electrode materials, suitable porous sintered powders, porous fibers, or even porous polymer films. Us patent No. 4,007,601 describes the use of evaporative cooling in a circulating porous hollow heat exchanger to obtain a cooled liquid.

Disclosure of Invention

Disclosed herein is a simplified cooling system for beverage and liquid containers that does not use any mechanical pump to supply liquid to the surface of the pervaporative substrate and does not rely on vacuum to enhance the cooling effect as in the prior art. A container is defined as any device or enclosure that holds a liquid, whether it be in an open or closed state to the external environment. In one embodiment, the method utilizes a pervaporation matrix which preferably forms part of the container body or shell and comprises from 5% to 100% of the total surface area of the container. The liquid contents within the container are then cooled directly at the surrounding liquid/film interface due to the latent heat of evaporation of water. The resulting liquid vapor is dissipated through the matrix to the ambient environment or to a collector or trap, for example, containing an absorbent material. Preferred containers include bottles, jars, large glass bottles, and boxes. In some embodiments, the container may be manufactured in larger structures, including a housing, a dispenser, and clothing.

In one embodiment, a pervaporatively cooled container is provided, comprising a container body comprising one or more walls, wherein at least a portion of said one or more walls comprises a pervaporative matrix, said matrix comprising a porous hydrophobic material, wherein said matrix allows passage therethrough of a small number of molecules of a volatile liquid vapor which it evaporatively cools the container, such evaporation cooling the container, including any substance within the container. In one embodiment, a pervaporatively cooled tube or tubule is provided comprising an elongated hollow tubular structure comprising an outer pervaporative layer, the outer evaporative layer comprising a hydrophobic material coextensive with a porous inner layer comprising a hydrophilic material, the inner layer forming a lumen through which a liquid may pass. In one embodiment, the tubular structure is formed from a hydrophobic porous tube, wherein the inner surface of the tube is chemically treated to be hydrophilic, thereby forming the inner layer.

In one embodiment, a container cooling jacket is provided, comprising a jacket body comprising an outer layer comprising a hydrophobic porous material; and an inner layer coextensive with and in fluid communication with the outer layer, the inner layer adapted to hold a volatile liquid, wherein the shape of the jacket body allows the inner layer to contact at least a portion of the container.

In a preferred embodiment, the container and cooling jacket may also include a renewable or disposable outer layer in direct abutment with or in contact with the pervaporation layer, the outer layer comprising a dewetting, absorbent material, or other substance capable of absorbing or adsorbing moisture or other liquids from the pervaporation.

In one embodiment, a cooling garment is provided comprising at least two layers: an outer layer comprising a pervaporative material comprising a hydrophobic pervaporative stack; optionally an intermediate layer comprising a thin liquid supporting barrier layer for the pervaporation layer; and an inner layer; wherein the outer layer is in communication with the body of coolant liquid flow and the inner layer is in thermal contact with the wearer of the garment. The wearer of the garment is pervaporatively cooled by a coolant liquid passing through the pervaporative material of the outer layer. In a preferred embodiment, the cooled garment comprises or is integrally formed as a garment, such as a protective garment or coat. The garment may also include a tube in fluid communication with the body of coolant liquid that allows the wearer of the garment to drink the coolant liquid, preferably water, through the mouth. In a preferred embodiment, the garment also includes a renewable or disposable outer layer comprising a dewetting or absorbent material that absorbs moisture or other liquids generated by pervaporation.

In a preferred embodiment, one or more of the following may also be present: the garment is either in direct contact with the skin or is in contact with a piece of fabric or material that is worn by the wearer and/or is part of the garment itself. The outer layer is pleated to increase the pervaporation surface area; the intermediate layer is a barrier to potentially harmful biological or chemical substances; and the inner layer includes patterned or serpentine regions formed by a heat sealing process.

In a related embodiment, the garment may also include or be in fluid communication with a reservoir that stores additional coolant liquid. The coolant can be fed from the container by gravity or by adsorption into the gap formed between the pervaporation matrix and the intermediate layer. Preferred coolant liquids include water, alcohols, and mixtures thereof.

In a related embodiment, a container, such as a bottle or backpack, is provided that contains a pervaporative material as described below.

Drawings

Fig. 1A and 1B show plan and exploded views of a vial having a substantially planar porous matrix wrapped or sleeved in a cylindrical shape.

FIG. 2 illustrates a partially exploded view showing a laminate structure including a layered film between two large pore layers, according to one embodiment.

Fig. 3A, 3B, 3C, and 3D show plan and cross-sectional views of embodiments in which the support ribs enhance the rigidity of the porous matrix.

Figure 4 shows a container containing a porous outer insulating layer. The jacket reduces direct radiative heating of the bottle interior surface, but allows pervaporation flow and latent heat loss.

FIG. 5 illustrates one embodiment of a container including a pleated substrate used as a method of effectively increasing the cooling surface area of the container. This results in a larger surface area of the container and shorter liquid cooling time.

Fig. 6A and 6B illustrate in plan and cross-sectional views one embodiment of a container that includes an adjustable sleeve to limit pervaporation flux and liquid loss from the container. The jacket preferably also reduces direct radiative heating of the interior surface of the bottle, but allows pervaporation flow and latent heat loss.

FIG. 7 shows a cross-sectional view of a two-layer pervaporation sleeve comprising a sponge or sponge-like material that can be used with a container.

FIG. 8 shows a cross-sectional view of another embodiment of a pervaporative cooling jacket for use on a central housing containing a liquid, such as a carbonated beverage.

FIG. 9 is a graph of time versus cooling effect versus pervaporation cooling equalization with various porous materials.

Figure 10 shows an embodiment of a pervaporatively cooled drinking cup.

11A, 11B, and 11C illustrate one embodiment of a pervaporatively cooled storage container (e.g., a chiller) having a pervaporative body shell and a pervaporative lid.

Figure 12 shows a preferred liquid dispensing reservoir with a pervaporation matrix.

Figure 13 shows an embodiment of a drinking backpack including a liquid-filled pleated pervaporatively cooled reservoir.

Figure 14 shows a pervaporatively cooled drinking bag in an optional porous mesh harness on a holder. Also shown is an internally wettable pervaporatively cooled tube that may be used in conjunction with the illustrated bag or other container to immediately chill or dispense liquids.

FIG. 15 illustrates a pervaporatively cooled jacket according to one embodiment.

The drawings illustrate preferred embodiments and are merely exemplary in nature and are intended to represent certain embodiments. To this end, the several figures contain optional features that are not necessarily included in any particular embodiment of the invention, and the shape, type, or particular configuration of the container or closure shown should not be taken as limiting the invention.

Detailed Description

Disclosed herein are containers or enclosures that utilize total evaporation to cool a liquid or item held therein. In a preferred embodiment, the container is constructed of a porous, gas permeable material. In one embodiment, the container forms part of a pervaporatively cooled garment.

The porous substrate can be made of a variety of different materials including, but not limited to, plastics, elastomers, metals, glass, and ceramic materials. Combinations of plastic, elastomer, metal, glass or ceramic materials may also be used. Such combinations may be intimate, such as mixing two or more components and co-sintering, or layered, such as a laminate derived from two or more materials. Combinations of different plastic, elastomer, metal, glass or ceramic materials may be sintered or fabricated into a laminate structure for a pervaporation container. Preferred plastics for the porous venting material include, but are not limited to, thermoplastic polymers, thermoset elastomers and thermoplastic elastomers. Preferred thermoplastic polymers include, but are not limited to, Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE), Medium Density Polyethylene (MDPE), High Density Polyethylene (HDPE), Ultra High Molecular Weight Polyethylene (UHMWPE), polypropylene (PP) and copolymers thereof, polymethylpentene (PMP), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), glycol-modified polyethylene terephthalate (PETG), polyether ether ketone (PEEK), Ethylene Vinyl Acetate (EVA), polyethylene vinyl alcohol (EVOH), polyacetal, polypropylene, polyethylene glycolNitrile (PAN), poly (acrylonitrile-butadiene-styrene) (ABS), poly (acrylonitrile-styrene-Acrylate) (AES), poly (acrylonitrile-ethylene-propylene-styrene) (ASA), polyacrylate, polymethacrylate, polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC), polyvinylidene chloride (PVDC), Fluorinated Ethylene Propylene (FEP), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), Polytetrafluoroethylene (PTFE), polyester, cellulosics, polyethylene tetrafluoroethylene (ETFE), Polyperfluoroalkoxyethylene (PFA), nylon 6(N6), polyamide, polyimide, polycarbonate, polyether ether ketone (PEEK), Polystyrene (PS), polysulfone, and polyether sulfone (PES). Preferred thermoset elastomers include styrene-butadiene, polybutadiene (BR), ethylene-propylene, acrylonitrile-butadiene (NBR), polyisoprene, polychloroprene, silicone, fluorosilicones, urethanes, hydrogenated nitrile rubbers (HNBR), Polynorbornenes (PNR), butyl rubbers (IIR) including Chlorobutyl (CIIR) and Bromobutyl (BIIR), fluorinated rubbers such as Viton * and Kalrez *, Fluorel^TMAnd chlorosulfonated polyethylene. Preferred classes of thermoplastic elastomers (TPEs) include Thermoplastic Polyolefins (TPOs), including commercially available Dexflex * and index *; elastic PVC blends and alloys; styrene Block Copolymers (SBCs) including SBS styrene-isoprene-styrene (SIS), styrene-ethylene/butylene-styrene (SEBS), and styrene-ethylene-propylene-styrene (ESPS), some commercially available SBCs include Kraton *, Dynaflex *, and chronorece^TM(ii) a Thermoplastic vulcanizates (TPVs, also known as dynamically vulcanized alloys) include those commercially available such as Versalloy *, Santoprene *, and Sarlink *; thermoplastic Polyurethanes (TPUs) include those commercially available as ChronoThane *, Versollan^TMAnd Texrin *; copolyester thermoplastic elastomers (COPE) include those commercially available as Ecdel *; polyether block Copolyamides (COPAs) include those commercially available as PEBAX *. Preferred metals for the porous material include stainless steel, zinc, copper and alloys thereof. Preferred glass and ceramic materials include quartz, borosilicate, aluminosilicate, sodium aluminosilicate, preferably sintered particles or fibers obtained from said materialsIn the form of a dimension.

The preferred method of making macroporous plastics is by a process known as sintering, in which powdered or granular thermoplastic polymer is heated and pressurized to partially agglomerate the granules and form a bonded macroporous sheet or part. The macroporous material comprises an interconnected network of macropores that form a random tortuous path through the sheet. Typically, the pore volume or percent porosity of the macroporous sheet is from 30% to 65% depending on the sintering conditions, although it may be greater or less than the stated range depending on the sintering method. Due to the modulation of chemical or physical properties, the surface tension of macroporous matrices can be made to repel or absorb liquids, but air and vapor can easily pass through. For example, Goldman, U.S. Pat. No. 3,051,993, the entire contents of which are incorporated herein by reference, discloses details of making macroporous plastics from polyethylene.

Porous plastics suitable for making pervaporatively cooled containers according to preferred embodiments, including macroporous plastics, may be manufactured in sheet form or molded to various specifications, and may be available from various sources. Porex corporation (Fairburn, left, usa) is one of them, and the porous plastic is provided under the trade name Porex *. Porous plastic sold under the name POREX * is commercially available in the form of sheets made from any of the thermoplastic polymers described above or molded to various specifications. The average porosity of such POREX * material may vary from about 1 to 350 microns depending on the size of the polymer particles used and the conditions employed during sintering. GenPore * (Reading, Pa., USA) is another manufacturer of porous plastic products, with pore sizes in the range of 5 to 1000 microns. MA Industries Inc (Peachtree, left california, usa) also manufactures cellular plastic products. Porvair Technology, Inc. (Wrexham, North Wales, England) is another manufacturer of cellular products, namely supplies cellular plastics (brand name Vyon)^TMPore sizes in the range of 5 to 200 microns) also supplied porous metal media (brand name Sinterflo *).

The basic size, thickness and porosity of the plastic selected to make the pervaporation matrix are determined by calculating the amount of vapor that must pass through the vent (flow rate) and the rate of heat transfer from the ambient back to the liquid in a given time. The flow rate (flow rate per unit area) of a given macroporous plastic varies according to the following factors: including pore size, percent porosity, and cross-sectional thickness of the substrate, and is generally expressed in volume per unit area per unit time. To obtain sufficient pervaporation cooling, the flow rate of vapor through the matrix should be such that the thermodynamic heat initially removed from the liquid at room temperature is greater than the heat absorbed from the surrounding environment. The temperature of the liquid in the vessel is chilled during pervaporation until the heat loss from the liquid due to pervaporation of the liquid through the matrix is equivalent to the heat gained from the surrounding environment.

In general use, "macroporosity" refers collectively to the total pore volume of a material or its macrostructure. The term "macroporous" generally refers to a material in which the individual pores are relatively large in size. The term "microporosity" generally refers to the individual pore size or distribution of pore sizes that make up the microstructure of the porous material. The term "microporous" generally refers to a material in which the individual pores are relatively small in size. For the purposes of this disclosure, pore size (diameter) is classified according to the definition of terms drafted by the International Union of Pure and Applied Chemistry (IUPAC) high molecular technical division at 2.26.2002. This standard divides the size of the holes into three categories: microporous (< 0.002 μm), mesoporous (0.002 to 0.050 μm), and macroporous (> 0.050 μm). Also for the disclosure herein, the pore volume will be discussed in terms of the "percent porosity" of the material. Large and medium pore materials with pore sizes of 0.05 μm or less can be used for pervaporation cooling. Preferred methods of manufacture include casting and stretching films of such materials.

Preferred porous materials include pores that are interconnected at opposite surfaces of the material (which will become the inner and outer surfaces) so as to be interconnected on both sides. But preferably the interconnection is not a direct connection of individual cylindrical tubes or pores formed through the material, but rather a network of pores forming a tortuous path.

For a single layer pervaporation matrix, the porous material is preferably a macroporous material having a pore size greater than or equal to 0.05 μm, preferably about 0.1 to 500 μm, and about 0.5 to 10 μm, including 0.25, 0.5, 1, 5, 15, 20, 40, 60, 80, 100, 150, 200, 250, 300, 350, 400, and 450 μm. In one embodiment, the matrix material in connection with the pervaporation container is between 0.1 and 100 μm, preferably between 0.5 and 75 μm. The porosity percentage (percentage of open area) of the material is preferably between about 10% and 90%, preferably between 30% and 75% or between 50% and 70%, including 20%, 40%, 60% and 80%. The thickness of the porous material is preferably in the range 0.025 to 7mm, including between 1 and 3 mm. Preferred thicknesses of the matrix material for the pervaporation container are about 0.05 to 5mm and about 0.1 to 3.0mm, including 0.2, 0.3, 0.5, 0.7, 1.0, 1.25, 1.5, 1.75, 2.0 and 2.5 mm. Other embodiments may have the above parameters less than or greater than the above values. For a single layer material, it is preferred that the material be hydrophobic or have a hydrophobic coating. For values stated in this paragraph and elsewhere in this specification, the stated ranges include values between the specifically mentioned values. In other embodiments, the material may have one or more properties with values outside the disclosed ranges.

The matrix material may be derived from plastic, elastomer, glass, metal, or combinations thereof. Some preferred matrix materials, as detailed above, include thermoplastic polymers, thermoset elastomers, thermoplastic elastomers, metals, glass, and ceramic materials. The matrix material may be purchased from various commercial sources or manufactured in various ways. White et al, U.S. patent 4,076,656, specifies a process in which a porogen is added to a molten or dissolved material, which can be filtered off with a solvent or extracted with a supercritical fluid after the material is stabilized and brought into final form. U.S. patent 5,262,444 to Rusincovitch et al discloses another method of forming porous materials by introducing a porogen which evolves into a gas after the material is treated to leave a porous structure. These patents are incorporated by reference herein in their entirety.

Although many of the matrix materials discussed herein are hydrophobic, oleophobic pervaporative materials may also be used when the pervaporative liquid is an organic liquid, such as an alcohol. Commercial plastic materials such as nylon, polysulfone, cellulose preparations can be obtained in hydrophilic grades. These hydrophilic materials can be milled into particles and sintered using existing techniques familiar to those skilled in the art to produce hydrophilic porous materials with high flux rates. Porous hydrophilic plastics, including macroporous plastics, can be manufactured as sheets or molded to specifications and are commercially available from a variety of sources, including Porex corporation. The porous hydrophilic fibrous material may have a pore size in the range of 20 to 120 μm and a percentage of pores in terms of its pore volume in the range of 25 to 80. Furthermore, the hydrophobic porous material may be rendered hydrophilic by one or more processes familiar to those skilled in the art, including, but not limited to, plasma etching, chemical etching, dipping with wetting agents, or applying a hydrophilic coating. Furthermore, if desired, a masking process may be used in conjunction with one or more treatment processes to selectively arrange the pattern of hydrophobic porous material in hydrophilic regions having a high flux rate.

For example, a multi-layer porous structure comprising two or more layers of porous material. Thin layers may be stacked into thicker layers by methods familiar to those skilled in the art. Multiple layer structures can be used to obtain a matrix with better mechanical and physical properties as seen in our tests. For example, the combination of a macroporous matrix of polyethylene with a thin layer of PTFE stretched over the liquid side of the container will increase the hydrophobicity and increase the liquid breakthrough pressure of water from about 5psi to over 30psi, but the layered matrix still maintains a pervaporation flux similar to that obtained with porous polyethylene itself. The thickness of the stack is preferably in the range of about 0.025 to 7000 μm, with the preferred average pore size, percent porosity and other properties described above.

Pervaporation matrix materials can also be obtained from porous materials made from the mixture. In a preferred embodiment, the porous material comprises a fluorinated resin including, but not limited to, polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), Polytetrafluoroethylene (PTFE), polyethylene tetrafluoroethylene (ETFE), Fluorinated Ethylene Propylene (FEP), Polyperfluoroalkoxyethylene (PFA), and/or fluorinated additives, such as Zonyl *, blends with selected polyolefins or other resins, preferably selected from the polyethylene (LLDPE, LDPE, MDPE, HDPE, UHMWPE) series, polypropylene, polyester, polycarbonate, ABS, acrylic resins, styrene polymethylpentene (PMP), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), Polyetheretherketone (PEEK), Ethylene Vinyl Acetate (EVA), polyacetal, poly (polyacrylonitrile-butadiene-styrene) (ABS), poly (acrylonitrile-styrene-Acrylate) (AES), poly (acrylonitrile-styrene-Acrylate) (ABS), Poly (acrylonitrile-ethylene-propylene-styrene) (ASA), polyester, polyacrylate, polymethacrylate, Polymethylmethacrylate (PMMA), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), nylon 6(N6), polyamide, polyimide, polycarbonate, polystyrene, and Polyethersulfone (PES). The elastomers may be used alone or in blends. Preferred elastomers include thermoset elastomers such as styrene-butadiene, polybutadiene (BR), ethylene-propylene, acrylonitrile-butadiene (NBR), polyisoprene, polychloroprene, silicone, fluorosilicones, urethanes, Hydrogenated Nitrile Butadiene Rubber (HNBR), Polynorbornene (PNR), butyl rubber (IIR) including Chlorobutyl (CIIR) and Bromobutyl (BIIR). The resulting blend comprises a sintered mixture having a porous structure of varying porosity, flexibility and mechanical strength, the variations being determined primarily by the non-PTFE or other non-fluorinated resin, and having a high water injection pressure determined primarily by the fluorinated resin, due to the preferential migration of the fluorinated resin to the pore surfaces during sintering. The percentage of porosity, pore size and thickness are preferably as described above. The mixed matrix material may be purchased commercially or manufactured according to various methods. U.S. patent No. 5,693,273 to Wolbrom describes in detail the process of co-sintering to produce porous plastic sheets that can be obtained from two or more layers of polymeric resin material, and U.S. patent No. 5,804,074 to Takiguchi et al describes in detail the process of producing plastic filters by co-sintering two or more polymeric resins in a molding process to produce filter components. Both of these patents are incorporated herein by reference in their entirety.

Pervaporation cooling

In a preferred embodiment, a simplified pervaporation cooling system for a container is provided that does not use any mechanical pump to supply liquid to the surface of the pervaporation substrate and does not rely on a vacuum to enhance the cooling effect. The provided methods utilize a pervaporation matrix that forms a portion of the container, which preferably forms a portion of the container shell, and comprises from about 5% to 100% of the total surface area of the container, including about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% of the total surface area. The liquid contents of the vessel are preferably cooled directly at the surrounding liquid/matrix interface by the latent heat of vaporization of the liquid, e.g., water or water/dissolved solid mixture or solution, in the vessel. In another embodiment, a full evaporative sleeve or shell is used to cool an object, such as a beverage bottle or container, in contact with the sleeve. The resulting liquid vapor is lost to the ambient environment or through the matrix in the absorbent material. In most vessels, natural convective and conductive heat transfer within the liquid is the dominant heat transfer mechanism that results in cooling of the liquid contents of the vessel. Depending on the size and other properties of the container, the cooling effect may be substantially uniform throughout the container.

The liquid contents of the pervaporation container or jacket act as a coolant. Preferably the liquid volume loss is bounded (margin); for example, in one embodiment, the liquid volume loss is about 15% within 24 hours even with significant external air circulation. Due to the high latent heat of evaporation of water (at 75 ° F, 583 cal/g), for example, 7 times the weight of ice is required to maintain the same temperature drop when water is lost by pervaporation. In addition to pervaporative cooling, the porous matrix has the added benefit of eliminating any pressure differential within the container due to carbonation of the beverage or due to consumption of the contents.

Referring to the drawings, there is shown in FIGS. 1A and 1B one embodiment of a vented pervaporatively cooled container constructed in accordance with the present invention. The wall 501 of the container constitutes at least a part of the pervaporation matrix. The vapor permeable matrix can comprise about 5% to 100% of the total surface area of the container. If the entire cover and housing (including top 500, walls 501 and bottom 502) is made of a porous matrix material, approximately 100% coverage can be obtained. In a preferred embodiment, the pervaporation surface area is greater than about 30% of the total container surface area and provides a substantial pervaporation flux to effectively cool the stored liquid below ambient temperature and maintain a liquid temperature below room temperature.

In one embodiment as shown in fig. 2, a stacked structure of two or more layers may be used. In one embodiment three layers of porous material 503, 504 and 505 are used to obtain a multilayer or laminated matrix. In one embodiment, a sintered macroporous matrix 505 of polyethylene with a thin layer 504 of porous PTFE on the liquid side of the container increases hydrophobicity and liquid intrusion pressure, but helps maintain pervaporation flux and good mechanical stability, as obtained with porous polyethylene itself. Furthermore, a third layer 503 of porous polyethylene sandwiched with a middle expanded PTFE layer 504 provides a scratch resistant surface near the inside of the container, making it safe for dishwashers (dishwashers) and substantially preventing or reducing damage to the soft expanded PTFE layer. In related embodiments, the stack may include more or less than three layers and/or different porous matrix materials.

In another embodiment, the inner layer 503 comprises a pervaporation matrix or a laminate matrix, the middle layer 504 comprises an insulating material with pores or other open spaces to allow vapor to pass through, and the outer layer 505 comprises a dehydrated or absorbent material.

The preferred orientation of the substrate is with the higher liquid injection (pressure) membrane facing the inside of the container, and the porous substrate support exposed to the air outside the container. The thickness of these porous materials is in the preferred embodiment in the range of from about 1/1000 "(0.025 mm) to 1/4" (6.4 mm). The porous material may provide structural rigidity, scratch resistance, and/or mechanical rigidity to the walls of the container.

In a preferred embodiment, the membrane or thin layer of material with small size (< 10 μm) pores may be selected from a group of highly hydrophobic materials, such as expanded polytetrafluoroethylene (ePTFE) and laminated between thicker porous supports, such as sintered polyethylene, which allows for considerable pervaporation flux. If only two layers are used, the thickness of each layer may vary from a monatomic surface treatment to 1/4 "(6.4 mm), or may be greater for foam insulation or porous composites. Porous ceramic materials include molecular sieves (zeolites) or porous polymer films (CSP technologies, Auburn, alabama) and organic matrix materials, such as activated carbon, can be used to substantially prevent or reduce the contamination of the liquid contents of the pervaporation cooling device or container by odors from the environment.

In a preferred embodiment, the layered structure comprises five layers: an inner ePTFE layer, a porous polypropylene layer, a layer of insulating polyurethane foam, a layer of ceramic material such as zeolite, and an outer wrapping layer of thin non-porous polyolefin or polyester. The device can be used to keep pervaporation in the device cool in a humid environment. Upon absorption of the vapor released from the liquid, the zeolite or other desiccant transfers heat directly or indirectly to the ambient environment while the insulated liquid contents within the pervaporation sleeve are cooled. The outer two layers comprising zeolite and non-porous film may be disposable or recyclable, for example dried in an oven.

In addition to being able to be applied directly to the porous substrate surface treatment in the structure, the porosity of the material or composite is preferably maintained at about 10% to 95%. This provides structural support within the matrix and improves the available pervaporation surface area, which in turn improves the overall cooling rate of the vessel. When the pore size of the substrate is less than 200nm, the knudsen diffusion effect dominates the upwind, effectively reducing vapor permeability and increasing the liquid to vapor conversion and cooling area to the air/vapor surface of the material. According to a preferred embodiment, preferred pore sizes include sizes in the range of about 0.5 μm to 30 μm, which is greater than the Knudsen diffusion range. The liquid intrusion pressure is greatly reduced at pore sizes above 100 μm, making the use of a single layer of macroporous material less desirable in some cases. If a combination of a membrane and a macroporous support is used, the larger pore size on the macroporous support becomes more desirable than when the combination is not used.

As shown in fig. 3A, 3B, 3C, and 3D, ribs 508 and 514 may be added to the inner and/or outer walls of the container to increase the rigidity of the container structure, prevent or reduce damage to the pervaporation media 507 and 513, and provide a hand grip 514. Fig. 3C and 3F show a sports version of the design in a ribbed configuration with a narrower neck.

The embodiment of fig. 4 includes a layer of open tubes (cells) and porous insulation 518 may be added to the outer surface of the container to allow for relatively unimpeded diffusion of vapor out of the system, but to reduce convection and radiant heat flow from the ambient environment into the liquid through the interior wall 517 of the container. An advantageous feature of such an insulator 518 is to help add structural support, enable a hand to hold the container and reduce or prevent damage to the substrate 517. As used herein, the term "pleated" includes corrugated surfaces and other structures that increase surface area. The pleated substrate may be pleated over the entire surface, or one or more portions may be pleated while other portions are smooth.

As shown in fig. 5, the pleated membrane or pleated porous sintered matrix 520 can enhance the pervaporation cooling of the container since the pervaporation cooling rate is a direct function of the surface area of the container.

Pervaporation containers and garments may include an adjustable or removable sleeve (sleeve) over the pervaporation matrix to enable selective covering or uncovering of part or all of the pervaporation material. Covering a portion of the pervaporative material reduces the vapor flow rate while still maintaining partial pervaporative cooling. Covering all substantially stops pervaporation and can be used as an "on-off" switch for the container or garment.

For example, the jackets 524 and 525 as shown in fig. 6A and 6B may be provided as a means of reducing the exposed surface area 527 and the overall evaporative cooling rate of the container, and thus the evaporation rate and cooling rate of the liquid, enabling greater control over the temperature of the container contents. Reduced cooling may be desirable in some situations, for example, when absolute pressure, relative humidity, and/or ambient temperature are low. As shown in fig. 6B, a space or gap 530 is preferably provided between one or more portions between the container and sleeve. The gap can serve as an isolation zone and/or as a flexible natural convection flow zone for the vapor, enabling the maintenance of pervaporative cooling and minimizing radiant heat transfer to the liquid contents of the vessel. The inner jacket 524 on the outside of the porous substrate 523 of the container is preferably attached to the pervaporation substrate at least at the top 522 and bottom 536 of the container housing, particularly if these sections are non-porous.

In one embodiment, a portion or all of the pervaporation garment or container may comprise a pervaporation sponge that both retains moisture within the sponge and provides cooling through pervaporation. A preferred embodiment is a two-layer pervaporation sponge, the inner layer of which comprises a hydrophilic material and the outer layer of hydrophobic material is attached to the inner layer of sponge. In this configuration, the inner sponge is capable of being wetted by water or other vaporizable liquid prior to use, and the porous, hydrophobic top layer substantially prevents or reduces the leakage of the pervaporative liquid at the outer surface of the pervaporative matrix. The liquid provides a heat transfer path through the wetted substrate directly to the inner surface of the vessel wall.

Fig. 7 shows a two layer pervaporation sponge 533 that can be used on glass bottles and containers. This construction enables the wet inner sponge layer 534 to be wetted by water or other vaporizable liquid, and the porous hydrophobic top layer 535 significantly prevents or reduces leakage of liquid coolant at the outer surface of the pervaporation matrix 535. The liquid provides a heat transfer path through the wet matrix directly to the vessel wall inner surface 532.

Figure 8 shows an alternative arrangement in which a cooling jacket 542 containing water or other pervaporative fluid 541 is filled through port 543 and used to cool the contents of a closed container shell 539. The housing includes one or more portions of the pervaporation matrix 537 and optionally includes one or more ribs 538 to enhance structural strength. The liquid contents 540 within the closed middle shell 539 can thus be sealed, substantially preventing or reducing loss of liquid volume or carbonation in this area. Furthermore, the pervaporative cooling efficiency of the container is not dependent on the nature of the enclosed liquid, it is dependent only on the volatility, heat of vaporization, ionic strength (tension) and solute of the water or liquid 541 used to fill the surrounding enclosure. As shown in fig. 7, the cooling jacket may also be made of a removable jacket comprising a hydrophobic pervaporation outer layer 535 and a porous liquid retaining or liquid absorbing inner layer 534.

Fig. 10 shows a pervaporatively cooled beverage cup that functions similarly to the pervaporative bottle shown in fig. 1A, 1B, 2, 3A and 3B. The porous matrix 555 allows the liquid to cool pervaporatively as soon as the liquid is injected into the cup. The bottle housing and ribs 556 provide structural support and thermal insulation.

This type of cooling jackets 533 and 542 can also be used in similar structures, such as food coolers, to reduce or maintain the temperature of the items below the ambient temperature. Shields 560, 565, and 573 as shown in fig. 11A, 11B, and 11C can be used on chillers to protect the pervaporative matrix 566 and can add mechanical rigidity and aid in the operation of the storage vessel. Through the liquid fill and drain ports 561 and 576, the covers 558, 572 and bottoms 563, 559 of the chiller can be filled with water or other pervaporative liquid 567 and 575. The interior of the lid 574 and bottom 569 of the container are preferably made of a non-porous material.

Fig. 12 shows a cold water dispenser comprising a large volume water bottle 579, such as a 5 or 10 gallon bottle, and a pervaporatively cooled liquid dispensing reservoir 580. As the liquid fills the reservoir 580 from the bottle 579, the pervaporative matrix 581 surrounding the reservoir cools the liquid prior to dispensing from the one or more outlet valves 583. Alternatively, one valve may be used for chilled water and one valve for hot water. Pervaporative cooling reduces or eliminates the need for electrical refrigeration mechanisms, such as refrigeration compressors. The plastic housing 582 of the reservoir 580 provides mechanical support for the pervaporation matrix 581.

In one embodiment, the pervaporation container may comprise one or more carrying straps to enable the container to be carried on the body. The container may be carried in a variety of ways, including, but not limited to, being strapped around the torso or limbs, or being carried in the form of a backpack or small bag. Potential market applications for this approach are well within the realm of pervaporatively cooled sports equipment to optimize player performance. FIG. 13 illustrates one embodiment of a pervaporatively cooled hydration package 585. The pack includes a body 588 that includes a pervaporation matrix 591, which in one embodiment is ribbed to provide a large pervaporation surface area. The bag is filled with pervaporative fluid through fill and drain port 587 and can be carried by means of one or more belts 586. A drinking tube 589 is preferably included in fluid communication with the interior of the container to enable the carrier to conveniently drink the fluid. Pervaporatively cooled hydration packs, including backpack-type wearable/portable containers, may be constructed of at least a portion of the bladder (blader) component of known various hydration packs, which may be made of pervaporative materials, such as by heat sealing, bonding, and/or sewing, which are known in the art and commercially available (e.g., camel bak, Petaluma, CA; HydraPark, Berkeley, CA).

In one embodiment, the hydration pack 585 comprises a laminate of at least two layers: (1) an outer layer 591 comprising a pleated or non-pleated pervaporation layer comprising a hydrophobic pervaporation stack; (2) the support layer 593, which preferably comprises a thin support layer for the pervaporation layer 591, serves as a liquid barrier. In some embodiments, for example for extended use, water is wicked by gravity or wicking from the liquid-containing reservoir 588 down into the void formed between the pervaporation matrix 591 and the intermediate layer 593.

The optional third layer preferably includes an insulating layer and is in direct contact with the skin (or in thermal contact with the skin through clothing) and provides a thermal barrier layer between the user and the drinking bag. This layer may be continuous or have a raised pattern (e.g., grooved, pleated, fluted) to allow air to pass between the user and the drinking bag. The optional third or fourth layer comprises a desiccant or absorbent material.

Fig. 14 shows a pervaporatively cooled beverage pouch with an optional mesh strip on the holder 599. The holder may comprise a non-webbing material which need only be capable of holding the pouch and preferably does not significantly interfere with pervaporation. Such a pervaporation bag can be strapped into a belt loop using a fastening strap 600, or attached to the side of an existing belt. The mesh fabric 601 allows the porous pouch matrix 595 to pervaporate along a free path. The bag 594 in a preferred embodiment includes three main portions: 1) a pervaporation body 595 containing a pervaporation matrix, 2) a water injection port 596 and 3) pervaporatively cooled drinking water pipes 597, 602 and a water outlet pipe 598 with a valve. The body 595 may be comprised of substantially all or part of a pervaporative matrix. The pervaporatively cooled drinking tube 602 in one embodiment includes a pervaporatively hydrophobic outer layer 604 that substantially prevents or reduces liquid leakage and performs pervaporatively cooling; and a liquid wettable inner layer 605. Once liquid is introduced through the center 603 of such a layered structure 602, the liquid permeates into the layer of hydrophilic material 605 creating a liquid lock that substantially prevents or reduces air from entering the center of the tube through the porous matrix 604. The liquid trapped in the hydrophilic matrix 605 is freely pervaporated through the hydrophobic outer matrix 604. The combination of the hydrophilic 605 and hydrophobic 604 matrices in a tubular form 602 provides the benefit of providing chilled potable water directly from the interior volume 603 of the tube when arranged in combination with either a pervaporatively cooled reservoir 594 or a non-pervaporatively cooled reservoir. A simple method of making such a device is to plasma treat the center of the hydrophobic porous PTFE tube. Alternatively, the drinking tube may be made of a non-pervaporative material.

In some embodiments, the pervaporation container is in the form of a lightweight liquid-filled (preferably water-filled) pervaporatively cooled garment that functions as a simple personal microclimate cooling system to relieve thermal stress in protective clothing worn by the individual at normal or elevated ambient temperatures. This type of garment can be made into protective garments. Such as chemical or biological protective clothing, or Nomex firefighter uniform, to form part of, or be worn in conjunction with, such protective clothing. Alternatively, such garments may be worn under a layer of body armor.

According to a preferred embodiment, the cooled clothing can be used for many purposes, including but not limited to fire and rescue personnel, military personnel and workers of hazardous (chemical and/or biological) substances, as well as sports enthusiasts, who can increase endurance by releasing more heat from their bodies while in motion. Pervaporative garments can also reduce the amount of infrared radiation emitted by the wearer. In a preferred embodiment, water or a mixture of water and ethanol (preferably about 5 to 15%) is used as the pervaporative coolant source to render the device substantially harmless and capable of providing additional functionality, such as providing the wearer with pervaporative cooling potable water as an additional bag. The cooled potable water can reduce the heat load of individuals wearing protective clothing or garments or individuals engaged in athletic activities, particularly for athletic activities requiring endurance. While a non-hazardous and/or potable coolant is preferred, any liquid capable of providing pervaporative cooling may be used, including methanol, isopropanol, non-potable water, and other liquids and solvents. Preferably, the coolant is selected to be compatible with the material with which it contacts within the garment.

In a preferred embodiment, the pervaporatively cooled garment is in the form of a jacket or vest. The pervaporatively cooled garment may be worn alone, or may be worn in combination, or may be integral with another article of clothing or garment, such as a protective garment. When incorporated or integrated into another garment, the pervaporatively cooled garment preferably includes an innermost layer for intimate contact (i.e., thermal contact) with the wearer. The pervaporatively cooled garment may be in direct contact with the skin, or with another piece of clothing worn by the wearer. In certain embodiments, the pervaporative garment includes a fabric or material covering a portion or all of the pervaporative matrix that directly faces the interior of the garment (i.e., the portion that is in contact or thermal contact with the wearer). Although pervaporative garments are discussed in the form of garments or vests having a particular construction, this discussion should not be construed as limiting the invention. The principles discussed herein may be used with a variety of pervaporatively cooled garments including garments, hats, belts, pants, leg wraps, and structures that wrap around a portion or portions of the body, such as a leg or arm (or portion thereof), or the neck.

Fig. 15 shows the structure of a preferred embodiment of the casing 608. The outer garment may be worn alone or the outer garment or vest may be hidden under a garment or protective suit, such as a chemical protective suit, or a Nomex firefighter uniform or body armor.

In a preferred embodiment, the garment comprises three or four laminate layers:

(1) optionally, a renewable or disposable outer layer 610 comprising a moisture-absorbing or absorptive material that absorbs moisture or other fluids from pervaporation;

(2) an outer layer 611 comprising a pervaporation layer, preferably pleated, comprising a pervaporation laminate, preferably hydrophobic;

(3) an intermediate layer 613 comprising a thin support layer that can act as a pervaporation layer for the liquid barrier layer, and in some embodiments, a barrier to potential pests and chemicals. For long term operation, water and other cooling fluids may in one embodiment pass from the liquid-containing reservoir 616, e.g., at the shoulder of the jacket, down into the gap formed between the pervaporation matrix and the intermediate layer by gravity or wicking; and

(4) the inner layer 615 is in contact with the skin, either directly or through a piece of fabric material, such as fabric or material that is part of the garment and/or a separate piece worn by the wearer. The inner layer preferably includes patterned or serpentine regions formed by heat sealing. In one embodiment, a simplified garment is provided comprising only layers 2 and 4 as described above.

Fluid may be disposed within the jacket through ports 607 in the jacket. In a preferred embodiment, the space 614 between the inner and middle layers forms an air bladder that provides a thermal barrier to the liquid in the cooled jacket when inflated through ports 618. When the air bladder collapses through the end opening in the air hose, the liquid layer comes into contact with the skin through the overlapping intermediate and inner layers and this provides the on-demand cooling. In another embodiment, a partitioned water reservoir in the jacket is sandwiched between the intermediate layer and the inner insulating layer to provide a cooling source for the potable water. Optionally, the reservoir may include a collapsible bag to prevent water sloshing, which may create undue or undesirable noise. In other embodiments, the garment may include a drinking tube 617 to enable the wearer to drink the liquid from the outer garment.

If a pervaporative garment having no moisture absorbing/absorbing outer layer is worn under a protective garment or other garment, such garment is preferably permeable to the pervaporative fluid or the garment, having vents, apertures or other openings to allow the passage of the pervaporative fluid.

In some embodiments, the pervaporative garment further comprises a renewable or disposable outer layer comprising a moisture-absorbing or absorbent material capable of absorbing moisture or other fluids from pervaporation. Suitable moisture absorbing or absorbent materials for the aqueous pervaporation fluid include, but are not limited to: ammonium sulfate, molecular sieves, and polyacrylic acid. The moisture-absorbing/absorbent outer layer can be discarded after use or it can be regenerated, for example by heating and/or reducing pressure. In a preferred embodiment, the moisture absorbing/absorbing layer absorbs at least about 3 to 4 times its weight in water. The process by which the layer absorbs water is preferably endothermic or at least minimally exothermic. In preferred embodiments, this layer provides a high degree of absorption, dimensional stability and/or minimal heat generation due to hydration of water vapor in this layer. One skilled in the art will readily appreciate that the moisture absorbing or absorptive layer may be combined with any of the pervaporation containers described herein. When this type of pervaporative garment is used in or integrated with another garment, no apertures, vents, openings, etc. are required in the other garment, although they may be present if desired. In a related embodiment, the moisture absorbing/absorptive outer layer includes a material that is chemically resistant and/or substantially impermeable to chemical and/or biological agents to provide additional protection to the wearer.

The thermodynamic utility of this structure is briefly described below. Assume an average water vapor pervaporation flux of 4 x 10 through the porous matrix in still air at 75 ° F from table 1^-6g*cm^-2*s^-1And assuming that the water vapor flux doubled at 95 ° F to 8 x 10^-6g*cm^-2*s^-1. If the enthalpy of evaporation at 95 ℃ F. is 2400j/g, the energy consumption per unit area of the substrate is 1.9 x 10^-2Watt cm^-2. To achieve 25 Watts of power consumption, the surface area of the substrate used in the construction of such a drinking water bag requires 1500cm²Or 1.5 feet². The use of a pleated membrane or pleated porous sintered matrix enhances pervaporation cooling capability because pervaporation cooling capability is a direct function of the porous surface area of the jacket. To cool at this rate for 4 hours, approximately 150 ml of water would be consumed in the process. Thus a small amount of water of less than 0.5 pounds would be used for this process. It is reasonable to note that the water filling the jacket may weigh approximately less than 3 pounds or less.

As will be appreciated by those skilled in the art, the various layer configurations in the embodiments of the jacket, pouch and backpack discussed above are interchangeable, as are their other container configurations disclosed herein.

According to one embodiment, the preferred orientation of the multi-layer or multi-functional substrate is such that the surface of the substrate with the higher degree of liquid intrusion faces the inside of the garment and the back of the substrate support is exposed to the air outside of the garment. These porous materials have a thickness in the preferred embodiment of 1/128 "(0.2 mm) to 1/8" (3.2 mm). In one embodiment, the layered composite of membrane and pervaporation matrix is selected to provide high liquid intrusion pressure at the liquid/matrix interface with a highly hydrophobic material with small pore size, such as porous polytetrafluoroethylene (ePTFE) laminated between a thicker porous support, such as sintered polyethylene, while they have a large pervaporation flux.

Manufacturing method

There are several methods of making the pervaporation matrix portion of a pervaporation container or a pervaporation garment, including, but not limited to, sintering submillimeter-sized plastic particles in a mold cavity to directly form the pervaporation wall; thermally or ultrasonically laminating or welding together or within a suitable frame one or more pervaporated substrates; insert molding, wherein one or more sheets or cylindrical porous substrates are inserted into a mold cavity and a thermoplastic polymer is injection molded directly around the insert to form the desired composite with porous substrate portions; heat sealing; connecting the components by bonding; and/or all or a portion of the pervaporative garment or container may be assembled by stitching.

A laminate structure comprising two or more layers of porous material may be used to obtain a mechanically or physically better performing matrix. For example, the combination of a sintered macroporous matrix of polyethylene on the liquid side of the container with a thin layer of porous ePTFE increases hydrophobicity and increases the liquid penetration pressure of water from 5psi to 30psi, while the laminated matrix still maintains the same pervaporation flux as obtained with porous polyethylene itself.

Fig. 1A and 25B show the structure of a preferred embodiment of a pervaporation container having a wall section 501 containing a pervaporation matrix. The wall 501 is secured to the top 500 and bottom 502 of the container by, for example, insert molding, heat or ultrasonic welding, adhesive bonding, or other suitable means. The top 500 of the bottle shown in this example allows for a threaded fit and may be used with a vented bottle cap. The top portion 500 and bottom portion 502 may be manufactured by any suitable method, including molding, vacuum forming, and the like.

Fig. 3A and 3B illustrate a ribbed structure for a thin pervaporation matrix 507 for additional structural support. The ribs 508 give the container wall structural integrity and a rigid surface to enable a secure grip of the container. The ribs 508 can be disposed on the outside, inside, and/or one or more sides of the pervaporation matrix. The ribs 508 are preferably injection molded onto the pervaporation matrix 507 by insert molding. Alternatively, the ribs 508 may be sealed to the porous matrix 507 by ultrasonic welding, thermal welding, adhesive bonding, or the like, or the porous matrix 507 may be sealed to the ribbed container shell 508.

Fig. 3C and 3D show a kinematic version of the design of such a container that enables the container to be securely held by a neck 512. The finish 511 allows for a variety of closures, including snap-fit closures and screw-thread closures.

Fig. 4 shows an insulating hydrophobic open tubular foam layer 518 that allows water vapor to move through the open tubular structure, but blocks thermal convection and radiation from the container contents. Table 1 lists that the insulating matrix reduces the liquid loss rate while maintaining considerable pervaporation cooling. In a preferred embodiment, the insulating foam 518 is placed or removed like a resilient sleeve.

Increasing pervaporative cooling efficiency can be achieved by pleating the substrate to increase the surface area of the substrate in contact with the liquid. Fig. 5 illustrates a pleated container body 520 that enables greater pervaporation surface area per unit volume of liquid contained. This configuration can reduce the time taken to pervaporatively cool the volume of the container. A container having this configuration may be insert molded, or made with an adhesive or fused plastic to attach the ends to the bottom 521 and top 519 of the container.

Fig. 6A and 6B show sleeve 525 rotating on the outside of substrate 523. As the outer sleeve 525 rotates past the inner sleeve 524, a set of vertical slits 527 are formed that open and close to allow the pervaporation matrix 523 to be variably exposed, thereby reducing the vapor flow rate, but still maintaining adequate pervaporation cooling. Vertical sliding sleeves, the gap of which can be adjusted vertically instead of rotationally, can also be used in this type of construction. The inner and outer jackets 524 and 525 are made of a substantially non-porous material, such as plastic or metal that does not allow water vapor to pass through. Fig. 6B shows an annular sleeve that helps maintain a very small gap 530 between the porous substrate 523 and the stationary inner sleeve 524. This gap 530 acts as a shield to substantially prevent or reduce the direct transmission of convective and radiant heat to the porous matrix 523 of the main vessel body. In addition, the gap 530 allows steam to flow outside of the annular region 527. Sleeves 524 and 525 may also be used with pleated pervaporation surface 520 as shown in fig. 5. Also, the sleeves 524 and 525 may be prevented from outside the container by sliding them over the outside of the container. The inner housing 524 may be attached or welded in place.

Fig. 7 and 8 show an embodiment of a jacket of a pervaporation container. As shown in fig. 7, the cooled jacket may be manufactured as a removable jacket comprising a hydrophobic pervaporation outer layer 535 and a porous liquid retaining or absorbing inner layer 534. In the embodiment of fig. 8, the outer jacket 541 is filled with water or other volatile fluid 541 through a special port 543, and the inner liquid container 540 is maintained at substantially ambient temperature. One advantage of this configuration is that carbonated beverages can be stored in the container without loss of carbonation. In addition, liquids with low pervaporation tendencies, e.g., electrolyte or sugar rich liquids, can be placed in the inner chamber 540 of the container, while distilled water or other liquid 541 susceptible to pervaporation is placed in the outer chamber, with a sufficient temperature drop readily achieved.

Another embodiment of a pervaporation structure as shown in fig. 7 and 8 is for an oleophobic pervaporation matrix that holds an organic liquid, such as ethanol. In this configuration, the outer jackets 533, 542 are filled with ethanol and serve as pervaporative coolants 534, 541.

Fig. 10 shows a pervaporatively cooled drinking cup similar in function to the container of fig. 1A, 1B, 2, 3A and 3B. The flat pervaporative matrix is wrapped around the cup 555 or sleeved in a cylindrical shape over the cup and the material is attached by bonding, potting, heat welding or ultrasonic welding. Insert molding may also be used to directly attach the material to the bottle holder and wall.

11A, 11B, and 11C illustrate the configuration for creating a cooling reservoir for holding beverages and food 568. In this configuration, the cover 558, the cooler walls 559 and 564, or preferably both the cover 572 and the walls 559 and 564, contain pervaporation jackets 566 and 578 that are filled with liquid. The container may also include one or more insulating layers. The container can be used to store food and beverages 568 for several days below ambient temperature. In one embodiment, cooler body assembly 563 may operate by placing planar pervaporative matrix 556 inside of housing 564 and attaching the material by adhesive, potting, heat welding, or ultrasonic welding. Alternatively, the material 556 may be directly attached to the frame or wall 564 by insert molding.

One solution proposed for reducing thermal stress is based on the concept of pervaporation. Chilled drinking water bags or other cooling garments using pervaporative cooling mechanisms, for example, not only find application in military as a cooling system for personnel, but also for sports enthusiasts who release more heat from their bodies in competitions thereby increasing their tolerance. The use of water or a mixture of water and ethanol (preferably 5 to 15%) as a source of pervaporative coolant makes the device harmless and provides additional functionality, such as an additional water bag for pervaporatively cooling the potable water. The chilled potable water also reduces the heat load on the person wearing the protective suit or clothing.

The pervaporative drinking package described herein has a structure similar to the pervaporative beverage cooling bottle described above. The efficiency of cooling by pervaporation (2400J/g) was 5 times higher than that of ice at room temperature (77 ℃ F.) on a mass basis, compared to the heat of fusion (335J/g) plus the amount of liquid heating (105J/g). The data provided in tables 1, 2 and 3 show what happens with pervaporatively cooled bottles at different air flow rates at different room temperatures and relative humidities of 30% to 40%.

Fig. 14 illustrates one embodiment of a pervaporatively cooled beverage pouch 594, showing an alternative mesh harness retainer 599. In one embodiment, the harness is directly connected to body 595 and no fasteners, whether silk-screened or not, are used. A pervaporation bag like this can be threaded onto the shoulder, strapped into a loop, or attached to the side of an existing belt using a securing strap 600 or similar other attachment means. In one embodiment, webbing 601 is sewn with a nylon mesh, and fastening strap 600 is a Velcro, nylon/Velcro composite, or other synthetic material in nature. The various portions of the porous matrix 595 of the bag may be heat sealed, heat welded, ultrasonically welded or adhesively laminated, or assembled as discussed herein with respect to other associated containers. In one embodiment, the pervaporatively cooled drinking tube 602 includes a pervaporatively cooled outer layer 604 that substantially prevents or reduces liquid leakage and pervaporatively cools, and a liquid wettable inner layer 605. Once liquid is introduced through the center 603 of such a layered structure 602, the liquid passes through the hydrophilic material creating a liquid lock 605 that prevents or greatly reduces the amount of air entering the tube center 603 through the porous matrix 604. The liquid trapped in this hydrophilic matrix 605 is freely pervaporated through the hydrophobic outer matrix 604. The benefit of this combination of hydrophilic 605 and hydrophobic 604 matrices in the form of a tube 602 is that cooled drinking water is provided directly from the inner tube volume. As mentioned above. Such tubes may be used with pervaporative or non-pervaporative water bags, or may be used with other containers, both pervaporative and non-pervaporative. One method of making a pervaporated tube 602 is to plasma treat the center of the hydrophobic porous PTFE tube, making the interior 605 of the tube hydrophilic.

Operation of pervaporative cooling devices

The preferred construction of the pervaporative cooling device is simple and can be operated at ambient conditions to cool and/or retain the fluid or solid matter within the container without the weight and reliability disadvantages associated with mechanical pumps or the need for an external mechanical vacuum to increase the pervaporative cooling rate. In a preferred embodiment, the radial dimensions of the container of fig. 1A are sufficiently large so that convective mixing is obtained by natural convection of the liquid contents. This is because, in some cases, the thermal conductivity of the liquid alone is not high enough to effectively maintain a substantially uniform temperature distribution throughout the container. When the liquid at the inner wall of the container is cooled, the density of the liquid at the inner wall is reduced compared to the liquid at the center. This is due to the difference in density, the cooler liquid flowing down the side walls of the container to the bottom of the container where it is carried upward to circulate in the middle of the container, a process which is the opposite of forced convection, known as natural convection. When the cooling rate is high enough, the convective vortex is interrupted from the side of the vessel, increasing the mixing rate.

These phenomena and their occurrence can be foreseen with dimensionless parameters of calculation, namely the grazing number (the parameter used for the buoyancy of the fluid in the gravitational field) and the prandtl number (the parameter describing the thermal and volumetric properties of the fluid). The combination of these two parameters makes it possible to calculate the nusselt number (total heat transfer parameter). Natural convection within the pervaporation vessel enables convective heat transfer through the buoyant fluid at the point of heat transfer through the same liquid medium, which will enhance the cooling efficiency and device cooling rate.

Table 1 lists the end-point pervaporative cooling data and the effect of the porous insulating matrix at 30% to 40% relative humidity and different air flow rates. Tables 2 and 3 list endpoint water pervaporation cooling data at different relative humidities and in the presence of shadows (table 2) and direct sunlight (table 3). The pervaporative material is PTFE (polytetrafluoroethylene) or sintered UHMWPE (ultra high molecular weight polyethylene). X-7744, X-6919 and 402HP are the UHMWPE materials of different porosities, different pore sizes and different thicknesses listed in these tables

TABLE 1

Matrix material	Porosity of the material	Pore size (μm)	Thickness s (mm)	Loss of fluid (%/hour)	Flux (gcm)2/s)*106	Cooling (F degree)	Cooling at 2MPH (F.)	Cooling at 5MPH (F.)
									Comparison 1(PF)	Is free of	Is free of	1.5	0.0	0.0	0.0	0.0	0.0
Comparison 2(PF)	Is free of	Is free of	1.5	0.0	0.0	0.0	0.0	0.0
									PVDF	75％	0.5	0.1	0.4-3.0	1.9-7.6	12.7	14.3	14.8
UMWWPE	35-50％	7	0.6	0.3-1.0	1.2-6.6	10.6	12.6	13.0
									PVDFw/foam insulation	75％	13.5	5.1	0.4-1.9	2.0-6.5	12.1	11.5	10.7
UHMWPEw/foam insulation	35-50％	20	5.6	0.3-0.8	2.2-5.2	9.8	10.5	11.2

TABLE 2

shaded/RH 38.6%/75 ° F matrix material	Porosity of the material	Pore size (μm)	Thickness (mm)	Temperature (° F)	Pervaporation cooling (DEG F)
						COMPARATIVE #1(PE)	Is free of	Is free of	1.5	72.2	-
COMPARATIVE #2(PE)	Is free of	Is free of	1.5	71.9	-
						X-7744	35-50％	7	0.6	63.6	8.4
X-6919	35-50％	＜15	1.6	65.1	6.9
						402HP	40-45％	40	0.6	63.4	8.7
402HP	40-45％	40	1.3	64.7	7.3
						Supported PTFE	75％	＞50	0.3	63.4	8.7

TABLE 3

sunny/RH 41.0%/77 ° F (sensor under shadow) matrix material	Porosity of the material	Pore size (μm)	Thickness (mm)	Temperature (° F)	Pervaporation cooling (DEG F)
						COMPARATIVE #1(PE)	Is free of	Is free of	1.5	93.6	-
COMPARATIVE #2(PE)	Is free of	Is free of	1.5	93.3	-
						X-7744	35-50％	7	0.6	71.3	22.2
X-6919	35-50％	＜15	1.6	73.1	20.4
						402HP	40-45％	40	0.6	73.1	20.4
402HP	40-45％	40	1.3	73.7	19.7
						Supported PTFE	75％	＞50	0.3	73.1	20.4

Table 1 lists the endpoint water pervaporation cooling data and the effect of 1/16 "open tubular porous urethane (urethane) insulation matrix at 30% relative humidity at different ambient air flow rates. Tables 2 and 3 list endpoint water pervaporation cooling data under different relative humidity and shade or with direct solar radiation. The pervaporative material in these three tables is PTFE or sintered UHMWPE (ultra high molecular weight polyethylene).

An additional enhanced cooling effect of the container can be seen when the external relative humidity drops and if the container is placed in direct sunlight. Lower external humidity increases the vapor condensation gradient and external heating raises the liquid temperature and vapor pressure, which results in an increase in pervaporation flux. Depending on the ambient conditions, the geometry of the vessel, and the choice of materials, the method is capable of maintaining sub-ambient cooling in the vessel at 22 ° F below ambient temperature. See table 3. For a 700 ml liquid volume, as shown in fig. 9, the time to achieve this cooling temperature for various pervaporation matrices and combinations thereof is about 2 hours.

One preferred embodiment of the evaporative cooling vessel comprises a single or combined porous matrix with a pervaporation layer having a thickness of about 0.025mm (0.001 inch) to 10mm (0.394 inch). Furthermore, in order to increase the efficiency of the pervaporation process, the number of matrices is preferably such that the heat conduction thereof is minimized. Preferably, the matrix does not substantially impede the dissipation of the vapor, and thus, in one embodiment, the pore size is preferably above about 100 nm. Preferred surface porosities of the substrate are between about 15 and 90%, including 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80 and 85%. Porous substrates made with hollow molten particles or open tubular porous substrates can help to substantially prevent or reduce undue heat transfer from the surrounding environment to the vessel.

The various methods and techniques described above provide a part of many ways to implement the invention. It is, of course, to be understood that not necessarily all objects or advantages described may be achieved in accordance with any particular embodiment or any other single embodiment described herein. Thus, for example, those skilled in the art will recognize that the method or article of manufacture performed in a manner that achieves or optimizes one advantage or group of advantages as taught herein does not necessarily achieve other objectives or advantages as may be taught or suggested herein.

Also, those skilled in the art will recognize the interchangeability of various features of different embodiments. Likewise, one of ordinary skill in the art will be able to mix and match the various features and steps discussed above, as well as other known equivalents for such features and steps, to perform methods in accordance with the principles disclosed herein.

While the invention has been described in terms of several embodiments and examples, it will be appreciated by those skilled in the art that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and obvious modifications and equivalents thereof.

Claims (31)

1. A pervaporatively cooled container, comprising:

a container body comprising one or more walls;

wherein at least a portion of the one or more walls comprises a pervaporation matrix comprising a porous, hydrophobic material, wherein the matrix allows a small number of molecules of the volatile liquid vapor to pass through the matrix, the evaporation of which cools the container.

2. A pervaporatively cooled container according to claim 1, wherein the matrix further comprises a thin hydrophobic or oleophobic porous material laminated to or deposited on the porous hydrophobic material.

3. A pervaporatively cooled container according to claim 2, wherein the matrix is oriented on the container body such that the layer of porous hydrophobic material faces the interior of the container.

4. A pervaporatively cooled container according to claim 1, wherein at least 10% of the surface of the one or more walls comprises said matrix.

5. A pervaporatively cooled container according to claim 1, further comprising a base attached to the one or more walls.

6. A pervaporatively cooled container according to claim 1, further comprising a renewable or disposable outer layer directly adjacent at least a portion of the container body, said layer comprising a dewetting or absorbing material which absorbs moisture or other liquids resulting from pervaporation.

7. A pervaporatively cooled container according to claim 1, wherein the matrix comprises an inner layer comprising a highly hydrophobic porous material disposed between two outer layers of porous hydrophobic material.

8. A pervaporatively cooled container according to claim 7, wherein the pore size and thickness of the inner layer is less than the pore size and thickness of the outer layer.

9. A pervaporatively cooled container according to claim 7, wherein the inner layer comprises PTFE and the outer layer comprises polyethylene.

10. A pervaporatively cooled container according to claim 1, wherein the container further comprises a plurality of support ribs.

11. A pervaporatively cooled container according to claim 1, wherein the matrix comprises hollow or expanded particles which are melted or bonded together to reduce heat transfer to the matrix and loss of pervaporative cooling efficiency.

12. A pervaporatively cooled container according to claim 1, further comprising an insulating jacket surrounding at least a portion of the one or more walls.

13. A pervaporatively cooled container according to claim 12, wherein the insulating sleeve comprises a porous material.

14. A pervaporatively cooled container according to claim 12, wherein the insulating sleeve is generally tubular and has one or more openings in its wall, whereby the sleeve may be rotated about the container to selectively cover or expose portions of the pervaporative matrix.

15. A cooling jacket for a container, comprising:

a jacket body comprising

An outer layer comprising a hydrophobic porous material; and

an inner layer coextensive with and in fluid communication with said outer layer, said inner layer adapted to retain a volatile liquid;

wherein the jacket body is shaped to enable the inner layer to contact at least a portion of the container.

16. A cooling jacket according to claim 15, wherein the inner layer comprises a sponge-like material.

17. The cooling jacket according to claim 15, wherein the inner layer comprises one or more void spaces.

18. The cooling jacket of claim 17, wherein the inner layer further comprises an opening that can be sealed to allow refilling and sealing of the inner layer.

19. A cooling jacket according to claim 15, wherein the jacket body is substantially cylindrical.

20. The cooling jacket according to claim 15, further comprising an intermediate layer between the inner and outer layers.

21. A cooling garment, comprising:

an outer layer comprising a pervaporative material, the pervaporative material comprising a pervaporative matrix having hydrophobic properties; and

an inner layer;

wherein the outer layer is in fluid communication with the body of cooling liquid and the inner layer is in thermal contact with a wearer of the garment.

22. The cooling garment of claim 21, further comprising an intermediate layer comprising a thin liquid supporting barrier layer for the pervaporation layer.

23. A cooling garment according to claim 21, wherein the cooling garment is integrated or integrated with an article of clothing or protective clothing.

24. The cooling garment of claim 21, further comprising a tube in fluid communication with the body of cooling fluid to enable a wearer of the garment to drink the cooling fluid through the mouth.

25. The cooling garment of claim 21, further comprising a renewable or disposable outer layer comprising a de-humidified or absorbent material that absorbs moisture or other fluids from pervaporation.

26. The cooling garment of claim 21, wherein the outer layer is pleated to increase pervaporative surface area.

27. The cooling garment of claim 21, wherein the intermediate layer is a barrier layer to potentially harmful biological or chemical substances.

28. A cooling garment according to claim 21, wherein the inner layer comprises patterned or serpentine regions formed by a heat sealing process.

29. A pervaporatively cooled tube or tubule comprising

An elongate hollow tubular structure comprising an outer pervaporation layer comprising a hydrophobic material coextensive with a porous inner layer comprising a hydrophilic material, the inner layer forming a lumen through which a liquid can pass.

30. The tube of claim 29, wherein, in use, liquid permeates into the porous inner layer creating a liquid lock, the inner layer substantially reducing the amount of air entering the tubular structure through the outer layer.

31. The tube of claim 29, wherein the tubular structure is comprised of a hydrophobic porous tube, wherein the inner surface of the tube is chemically treated to render it hydrophilic.