Self-heating of self-cooling containers

Abstract

A self-heating container ( 10 ) has an internal cavity ( 22 ) for its contents and an external cavity ( 20 ) for a heating mechanism, for example, comprised of first and second chemically reactive materials which are arranged to be mixed when heating is required. A protective cover ( 52 ) is engaged on the can over the top end member ( 14 ) to prevent access to a ring-pull opener ( 50 ). The protective cover ( 52 ) has been shrunk onto the can such that it cannot be removed normally. However, when the can and its contents have been heated to the predetermined temperature by operation of the heating mechanism, the protective cover ( 52 ) expands in size relative to the can ( 10 ) and is removable. The ring-pull opener ( 50 ) may then be opened to enable the contents to be dispensed. After opening, the cover ( 52 ) may be reengaged on the can to provide an insulated drinking lip which protects the consumer against the heat of the can and provides a more pleasant surface to drink from than the edge of the can itself.

1 . A method of protecting a self-heating or a self-cooling container against premature opening, the container comprising a heating or cooling mechanism for heating or cooling contents of the container, and having opening means operable to enable access to the container contents, wherein a protective cover is arranged on the container so as to prevent operation of the opening means, and wherein the method comprises the step of enabling the removal of the protective cover only when the container and its contents have attained a predetermined temperature.  
     
     
         2 . A method of protecting a container as claimed in  claim 1 , wherein the predetermined temperature is generally the steady state temperature to which the container and its contents are brought a predetermined time after the operation of the heating or cooling mechanism.  
     
     
         3 . A method of protecting a container as claimed in  claim 1  or  claim 2 , wherein the materials of the container and of the protective cover are arranged to react differently to changes in the temperatures to which they are subjected such that removal of the protective cover is enabled by the reactions of the container and of the protective cover to the predetermined temperature attained by the container and its contents.  
     
     
         4 . A method of protecting a container as claimed in any of  claims 1  to  3 , wherein the protective cover is retained in position to prevent operation of the opening means by retaining means arranged to change state with changes in temperature.  
     
     
         5 . A method of protecting a container as claimed in  claim 3 , for a self-heating container, wherein, upon heating, the protective cover is arranged to expand relative to the container such that when the container and its contents have reached the predetermined temperature, the protective cover may be removed.  
     
     
         6 . A method of protecting a container as claimed in  claim 4 , for a self-heating container, wherein the protective cover is retained in position to prevent operation of the opening means by retaining means arranged to melt or soften when heated.  
     
     
         7 . A method of protecting a container as claimed in  claim 3 , for a self-cooling container, wherein, upon cooling, the protective cover is arranged to contract less than the container to provide relative expansion of the protective cover with respect to the container when the container and its contents have reached the predetermined temperature, whereby the protective cover may be removed.  
     
     
         8 . A method of protecting a container as claimed in  claim 4 , for a self-cooling container, wherein the protective cover is retained in position to prevent operation of the opening means by retaining means arranged to become frangible when cooled.  
     
     
         9 . A method of protecting a container as claimed in any preceding claim, wherein the container has a first end closed by an end member in which the opening means is formed, and wherein the protective cover is a removable cover arranged to engage on the container to enclose the first end member and thereby prevent access to the opening means.  
     
     
         10 . A method of protecting a container as claimed in any of  claims 1  to  8 , wherein the container has a first end closed by an end member in which the opening means is formed, and wherein the protective cover is engaged over the opening means to prevent access thereto.  
     
     
         11 . A self-heating or a self-cooling container having a heating or cooling mechanism for heating or cooling contents of the container, and opening means operable to enable access to the container contents, said container further comprising a protective cover arranged on the container so as to prevent operation of the opening means, the arrangement being such that the removal of the protective cover is enabled only when the container and its contents have attained a predetermined temperature whereby the container is protected against premature opening.  
     
     
         12 . A container as claimed in  claim 11 , wherein the materials of the container and of the protective cover are arranged to react differently to changes in the temperatures to which they are subjected such that removal of the protective cover is enabled by the reactions of the container and of the protective cover to the predetermined temperature attained by the container and its contents.  
     
     
         13 . A container as claimed in  claim 11  or  claim 12 , further comprising retaining means to retain the protective cover in position to prevent operation of the opening means, wherein the retaining means are arranged to change state with changes in temperature.  
     
     
         14 . A self-heating container as claimed in  claim 12 , wherein the protective cover is arranged, upon heating, to expand relative to the container such that, when the container and its contents have reached the predetermined temperature, the protective cover is removable.  
     
     
         15 . A self-heating container as claimed in  claim 13 , wherein said retaining means are arranged to melt or soften when heated.  
     
     
         16 . A self-cooling container as claimed in  claim 12 , wherein the protective cover is arranged, upon cooling, to contract less than the container such that, when the container and its contents have reached the predetermined temperature, the protective cover has expanded relative to the container and is removable therefrom.  
     
     
         17 . A self-cooling container as claimed in  claim 13 , wherein said retaining means are arranged to become frangible when cooled.  
     
     
         18 . A container as claimed in any of  claims 11  to  17 , further comprising a first end closed by an end member in which the opening means is formed, and wherein the protective cover is a removable cover arranged to engage on the container to enclose the first end member and thereby prevent access to the opening means.  
     
     
         19 . A container as claimed in any of  claims 11  to  17 , further comprising a first end closed by an end member in which the opening means is formed, the protective cover being engaged over the opening means to prevent access thereto.  
     
     
         20 . A self-heating or self-cooling container comprising a tubular peripheral wall within which first and second separated cavities extend, the first cavity receiving the contents of the container, and the second cavity housing a heating or cooling mechanism, a first end member closing the first cavity, and a second end member closing the second cavity, and opening means operable to enable access to the contents of the container formed in, or associated with, said first end member, said container further comprising a protective cover for protecting against premature opening of the container, said protective cover being arranged on the container so as to prevent operation of the opening means, the arrangement being such that removal of the protective cover is enabled only when the container and its contents have attained a predetermined temperature.  
     
     
         21 . A self-heating or self-cooling container as claimed in  claim 20 , wherein the container and the protective cover react differently to changes in the temperatures to which they are subjected such that their relative sizes alter and removal of the protective cover is enabled when the container and it contents attain the predetermined temperature.  
     
     
         22 . A self-heating or self-cooling container as claimed in  claim 20  or  claim 21 , further comprising retaining means to retain the protective cover in position to prevent operation of the opening means, the retaining means being arranged to change state with changes in temperature.  
     
     
         23 . A self-heating container as claimed in  claim 21 , wherein the protective cover is arranged, when heated, to expand relative to the container such that, when the container and its contents have reached the predetermined temperature, the protective cover is removable.  
     
     
         24 . A self-heating container as claimed in  claim 22 , wherein the retaining means are arranged to melt or soften when heated.  
     
     
         25 . A self-cooling container as claimed in  claim 21 , wherein the protective cover is arranged, upon cooling, to contract less than the container such that, when the container and its contents have reached the predetermined temperature the protective cover has expanded relative to the container and is removable therefrom.  
     
     
         26 . A self-cooling container as claimed in  claim 22 , wherein the retaining means are arranged to become frangible when cooled.  
     
     
         27 . A container as claimed in any of  claims 20  to  26 , wherein said opening means are formed in said first end member, and the protective cover is engaged over the opening means to prevent access thereto.  
     
     
         28 . A container as claimed in any of  claims 20  to  26 , wherein said opening means are formed in said first end member, and the protective cover is engaged on the container to enclose the first end member and thereby prevent access to the opening means.  
     
     
         29 . A container as claimed in any of  claims 20  to  28 , wherein said second cavity extends within the first cavity, and the first cavity opens at one end of the peripheral wall and the second cavity opens at the other, opposite, end of the peripheral wall.  
     
     
         30 . A container as claimed in any of  claims 11  to  29 , wherein said protective cover is reengageable on the container and has a drinking hole such that the contents of the container can be drunk through the protective cover.  
     
     
         31 . A container as claimed in  claim 30 , wherein said protective cover is made of an insulating material.  
     
     
         32 . A container as claimed in  claim 30  or  claim 31 , wherein the drinking hole in the protective cover is closed by a breakable seal.  
     
     
         33 . A container as claimed in any of  claims 30  to  32 , wherein the protective cover is shaped to provide a drinking rim within which the drinking hole is formed, and wherein a recess is provided in the protective cover adjacent the drinking hole.  
     
     
         34 . A container as claimed in any of  claims 11  to  33 , wherein the protective cover comprises an end wall from the periphery of which a peripheral rim depends, the peripheral rim being appropriately shaped to engage on the peripheral wall of the container.  
     
     
         35 . A method of protecting a self-heating or a self-cooling container against premature opening substantially as hereinbefore described with reference to the accompanying drawings.  
     
     
         36 . A self-heating or a self-cooling container substantially as hereinbefore described with reference to the accompanying drawings.