Heat pack resistant to saddle-bagging

Abstract

A heat pack for use as a warmer mattress for infants is formed of a flexible container at least partly filled with a supercooled aqueous salt solution which is selectively trigger-activated to produce heat by exothermic crystallization. The container is compartmentalized, being divided into several compartments by a heat-sealing arrangement of upper and lower joined halves. When crystallization is initiated by activating the trigger, crystallization is propagated quickly into the several compartments, from each of which heat is thereby liberated, the compartments being shaped such that the crystallizing solution in each compartment is effectively trapped therein to substantially prevent saddle-bagging, and whereby the heat pack reliably and safely supports an infant upon the warmer mattress. The upper and lower halves are heat-sealed together in various possible heat seal patterns defining the compartments, as by sealed margins and heat-seal extensions extending inwardly from the peripherally margins. The triggering arrangement disclosed includes opposed puncturing devices under a sealing arrangement, incorporated crystals of the salt of the solution on the puncturing devices, which may be mutually squeezed together for causing puncturing of at least one side of the container for triggering. As a warmer mattress, the heat pack provides a gentle, warm, supportive non-saddle-bagging infant support surface, for use in medical institutions to support neonatal infants or otherwise when they are placed upon a surface for examination and care.