Self-heating or self-cooling containers

Abstract

A self-heating metal can ( 10 ) has an indented base ( 16 ) defining an external cavity ( 20 ) which is utilised to contain beating means. The heating means comprises quicklime ( 26 ) filled within a first chamber ( 28 ) and water within a second chamber ( 32 ) of the cavity ( 20 ). A breakable membrane ( 24 ) separates the two chambers ( 28, 32 ) and the second chamber ( 32 ) is closed by closure ( 30 ). Depression of a button ( 50 ) of the closure moves an elongate piercing member ( 42 ) to pierce the membrane ( 24 ) so that water from the chamber ( 32 ) flows over the quicklime ( 22 ) to cause the exothermic reaction.

1 . A self-heating or self-cooling container having a tubular peripheral wall, a top member closing one end of the peripheral wall, and a base member closing the other end of the peripheral wall, an internal cavity for the contents of the container being defined within the peripheral wall, wherein the base member is indented to define an external cavity which extends within the peripheral wall but is separated from the internal cavity, and wherein means for heating or cooling the contents of the container are received within said external cavity, said heating or cooling means comprising a breakable membrane dividing the external cavity into first and second chambers, a first reactant material sealed within the first chamber by said breakable membrane, a closure member closing said second chamber to retain a second reactant material therein, and piercing means movable to break or pierce the breakable membrane whereby said first and second reactant materials can mix.  
     
     
         2 . A self-heating or self-cooling container as claimed in  claim 1 , further comprising pressure venting means associated with the closure member and/or with the container.  
     
     
         3 . A self-heating or self-cooling container as claimed in  claim 2 , wherein a one way valve or seal is associated with the closure.  
     
     
         4 . A container for facilitating the mixing of first and second materials, the container comprising a cavity, a breakable membrane dividing the cavity into first and second chambers, a first material sealed within the first chamber by said breakable membrane, a closure member closing said second chamber to retain a second material therein, and piercing means movable to break or pierce the breakable membrane whereby said first and second materials can mix.  
     
     
         5 . A container as claimed in any preceding claim, wherein the closure member supports the piercing means and enables movement of the piercing means to break or pierce the breakable membrane.  
     
     
         6 . A container as claimed in  claim 5 , wherein the closure member comprises a periphery arranged to engage the container, and carries at least one elongate piercing member which extends from the inner surface of the closure member.  
     
     
         7 . A container as claimed in  claim 6 , wherein the or each elongate piercing member is fixed to the inner surface of the closure member, or is integrally formed therewith.  
     
     
         8 . A container as claimed in any of  claims 5  to  7 , wherein elongate piercing member(s) are mounted on a pushbutton or plunger construction supported within the closure member.  
     
     
         9 . A container as claimed in  claim 7 , further comprising hinge means formed in the closure member to enable movement of the piercing member(s) to pierce the breakable membrane.  
     
     
         10 . A container as claimed in  claim 6 , wherein the closure member and the piercing member(s) are formed from a plastics material, and the closure member is formed to provide the necessary movement for the piercing member(s).  
     
     
         11 . A container as claimed in  claim 10 , wherein an elongate piercing member is affixed to the closure member and upstanding therefrom, the arrangement being such that depression of the closure member adjacent the piercing member moves the member to pierce the breakable membrane.  
     
     
         12 . A container as claimed in  claim 11 , wherein the piercing member is arranged substantially centrally of the closure member.  
     
     
         13 . A container as claimed in  claim 11  or  claim 12 , wherein the elongate piercing member is integrally formed with the closure member.  
     
     
         14 . A container as claimed in any of  claims 10  to  13 , wherein the piercing member is mounted on the closure member by way of a button formed in the closure member, and wherein the button is moulded integrally with the closure member.  
     
     
         15 . A container as claimed in  claim 14 , wherein the button is defined by an annular groove and has a domed shape.  
     
     
         16 . A container as claimed in any preceding claim, wherein the closure member is arranged to clip onto the base of the container such that it acts to close its external cavity.  
     
     
         17 . A container as claimed in  claim 16 , wherein the closure member is provided with a peripheral rim which is appropriately shaped to clip onto the base of the container.  
     
     
         18 . A container as claimed in  claim 17 , wherein the closure member is circular, and its peripheral rim is annular, and wherein an annular groove is defined in the closure member, radially inwardly of the peripheral rim, and arranged to receive a base edge of the container.  
     
     
         19 . A container as claimed in  claim 17  or  claim 18 , wherein the closure member and its peripheral rim are shaped such that any increase in pressure within the second chamber of the external cavity tends to urge the rim into better engagement with the base edge of the container.  
     
     
         20 . A container as claimed in any preceding claim, wherein the first reactant material sealed within the first chamber is in a powder, granular, or other particulate form, and the second reactant material in the second chamber is a fluid.  
     
     
         21 . A container as claimed in any preceding claim, wherein the breakable membrane is of any material capable of sealing the first reactant material in the first chamber, and supporting the weight of that material when the container is in its normal upright position.  
     
     
         22 . A container as claimed in  claim 21 , wherein the breakable membrane is formed by a disc of a metal foil secured to the external cavity to extend across it.  
     
     
         23 . A container as claimed in  claim 21  or  claim 22 , wherein the external cavity is shaped to define an annular flange therein and wherein a disc shaped breakable membrane is then affixed to the annular flange after a charge of the first reactant material has been filled into the first chamber.  
     
     
         24 . A container as claimed in  claim 23 , wherein the disc shaped breakable membrane is affixed to the annular flange by way of a carrier member.  
     
     
         25 . A container as claimed in  claim 23 , wherein the periphery of the disc shaped breakable membrane is affixed directly to the annular flange.  
     
     
         26 . A self-heating or self-cooling container substantially as hereinbefore described with reference to the accompanying drawings.  
     
     
         27 . A container substantially as hereinbefore described with reference to the accompanying drawings.