US Patent 7942145 Rechargeable self-heating food container

A rechargeable, self-heating food container includes an inner chamber with a supersaturated salt solution and trigger means for initiating crystallization of the supersaturated salt solution. A rechargeable element for heating food includes a cylinder containing a supersaturated salt solution sealingly insertable into a food container, with a trigger in fluid contact with the supersaturated salt solution. A method of heating a food container includes providing a food container with an internal chamber, a supersaturated salt solution contained in the internal chamber, and a trigger to initiate crystal nucleation within the supersaturated salt solution in an exothermic reaction; and recharging by heating the food container until the salt crystals melt, and cooling the salt solution to a supersaturated state. A portable recharger for a rechargeable heating element includes an insulated sleeve with electric resistive heating element pluggable into an automobile or conventional ac outlet.