Heat transfer device

Abstract

A self cooling can has water on a pre-wetted wick ( 478 ), in a chamber and an adsorbent in another chamber communicable upon actuation of the can with the chamber. One or both of the chambers is at low pressure. Upon actuation the pressure of the wick drops, water vapour is absorbed by the adsorbent from the internal atmosphere and more water evaporates from the wick to replace it, thereby causing a cooling effect in heat generated in the adsorbent may be contained by but a take-up system, such as phase change material or microcapsules of high heat capacity material such as water.

1 . A self cooling beverage container having a beverage chamber adapted to hold a beverage, an adsorbent, an evaporative refrigerant, an isolator isolating said refrigerant from said adsorbent and an actuator adapted in use to communicate said adsorbent with said refrigerant so that, in use, said evaporative refrigerant evaporates and is adsorbed by said adsorbent, evaporation causing cooling of said beverage in use, a plurality of heat take up bodies comprised of heat take up material being provided in said body of adsorbent, said heat take up bodies each having a surface area in contact with said adsorbent, which said surface areas of said heat take up bodies are significantly larger than the respective surface areas of spheres of equivalent volume.  
     
     
         2 . A self cooling beverage container according to  claim 1  wherein said heat take up means comprise a plurality of elongate looped filaments.  
     
     
         3 . A self cooling beverage container according to  claim 2  wherein a substantial number of said looped filaments are connected to a common core.  
     
     
         4 . A self cooling beverage container according to  claim 3  wherein a majority formation of said looped filaments are connected to a common core at both ends of the loops.  
     
     
         5 . A self cooling beverage container according to  claim 1  wherein said heat take up means comprise substantially flattened tapes.  
     
     
         6 . A self cooling beverage container according to  claim 1  wherein said heat take up means comprise tubes.  
     
     
         7 . A self cooling beverage container according to  claim 6  wherein said tubes contain a fluid, or a phase change material.  
     
     
         8 . A self cooling beverage container according to  claim 7  wherein said tubes contain wax adapted to melt as said heat take up material absorbs heat.  
     
     
         9 . A self cooling beverage container according to  claim 6  wherein said tubes have a substantially helical shape.  
     
     
         10 . A self cooling beverage container according to  claim 1  wherein said heat take up means are arranged as a plurality of substantially flat and parallel plates.  
     
     
         11 . A self cooling beverage container according to  claim 1  wherein said heat take up means are arranged as elongate capsules.  
     
     
         12 . A self cooling beverage container according to  claim 11  wherein said capsules contain phase change material and have a retaining layer surrounding said phase change material such that in use said phase change material changes phase and is retained with said retaining layer.  
     
     
         13 . A self cooling beverage container according to  claim 12  wherein said retaining layer has a higher melting point than said phase change material.  
     
     
         14 . A self cooling beverage container according to  claim 13  wherein said phase change material comprises wax.  
     
     
         15 . A self cooling beverage container according to  claim 1  wherein said heat take up means are arranged as a plurality of filaments each having a first end connected to a common core and a second end which extends into said adsorbent.  
     
     
         16 . A self cooling beverage container having a beverage chamber adapted to hold a beverage; an adsorbent; an evaporative refrigerant; an isolator isolating said refrigerant from said adsorbent; an actuator adapted in use to communicate said adsorbent with said refrigerant so that, in use, said evaporative refrigerant evaporates and is adsorbed by said adsorbent evaporation causing cooling of said beverage in use; and a pre-wetted wick; said prewetted wick wetted before activation of the device with said evaporative refrigerant, and said wick being adapted to hold an amount of said evaporative refrigerant close to said beverage container, and wherein said wick is provided with apertures.  
     
     
         17 . A self cooling beverage container according to  claim 16  wherein said wick has a first surface spaced from a second surface by a body of material of said wick; said body of material of said wick having a wicking porous or voided structure adapted to enable said evaporative refrigerant to be wicked, in use, along said wick and where said apertures extend through said body of material from said first surface towards said second surface; said apertures being of a size such that the smallest cross-sectional dimension across said aperture is significantly bigger than an average pore or void dimension, thereby rendering said apertures less likely to block with solid, frozen, refrigerant in use than said pores or voids.  
     
     
         18 . A self cooling beverage according to  claim 16  wherein said wick has a first surface spaced from a second surface by a body of wicking material, and holes or recesses are provided in said wick extending from at least one of said surfaces.  
     
     
         19 . A self cooling beverage according to  claim 18  wherein said holes or recesses comprise at least some through-holes or recesses extending from said first surface to said second surface.  
     
     
         20 . A self cooling beverage container having a beverage chamber adapted to hold a beverage, an adsorbent body comprising adsorbent material, an evaporative refrigerant, an isolator isolating said evaporative refrigerant from said adsorbent body and an actuator adapted in use to communicate said adsorbent body with said evaporative refrigerant such that, in use said evaporative refrigerant evaporates and is adsorbed by said adsorbent material, evaporation causing cooling, in use; and wherein said adsorbent body is shaped so as to form channels within said adsorbent body so as to, in use, expose evaporated evaporative refrigerant to parts of said adsorbent body that otherwise said evaporative refrigerant would not reach if said adsorbent body were an unchannelled block of adsorbent material.  
     
     
         21 . A self cooling beverage container according to  claim 1  being further provided with a pre-wetted wick; said prewetted wick wetted before activation of the device with said evaporative refrigerant, and said wick being adapted to hold an amount of said evaporative refrigerant close to said beverage container, and wherein said wick is provided with apertures.  
     
     
         22 . A self cooling beverage container according to  claim 21  wherein said wick has a first surface spaced from a second surface by a body of material of said wick; said body of material of said wick having a wicking porous or voided structure adapted to enable said evaporative refrigerant to be wicked, in use, along said wick and where said apertures extend through said body of material from said first surface towards said second surface; said apertures being of a size such that the smallest cross-sectional dimension across said aperture is significantly bigger than an average pore or void dimension, thereby rendering said apertures less likely to block with solid, frozen, refrigerant in use than said pores or voids.  
     
     
         23 . A self cooling beverage container according to  claim 21  wherein said wick has a first surface spaced from a second surface by a body of wicking material, and holes or recesses are provided in said wick extending from at least one of said surfaces.  
     
     
         24 . A self cooling beverage container according to  claim 23  wherein said holes or recesses comprise at least some through-holes or recesses extending from said first surface to said second surface.  
     
     
         25 . A self cooling beverage container according to  claim 1  wherein said adsorbent comprises an adsorbent body comprising adsorbent material, said adsorbent body is shaped so as to form channels within said adsorbent body so as to, in use, expose evaporated refrigerant to parts of said adsorbent body that otherwise said evaporative refrigerant would not reach if said adsorbent body were an unchannelled block of adsorbent material.