Abstract

A flameless heater includes two non-woven polyester sheets which are thermally bonded together to form a number of pockets. Each pocket is filled with a powder mixture of Mg--Fe alloy, NaCl, antifoaming agents, and an inert filler. The outer surfaces of the polyester sheets are preferably treated with a food grade surfactant. The polyester sheets are gas and water permeable over substantially their entire surfaces and the filled pockets define intervening channels where the polyester sheets are bonded. The resulting heater can be made approximately 50% thinner and 50% lighter than a conventional FRH. In use, both the channels and the permeability of the sheets allow water to wet the powder rapidly and initiate the chemical reactions quickly. The byproducts of the chemical reactions cause the pockets to inflate slightly thereby adding sufficient rigidity to the heater to support a food packet. The byproducts of the chemical reactions exit the pockets through the permeable sheets and are directed away from the reaction via the channels. This rapid removal of the byproducts of the reaction enhances the efficiency of the reactions which allows a smaller, lighter heater to produce the same heat as a larger, heavier heater. By avoiding sintering processes, the heater can be easily and economically mass produced.