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Self-regulating heat pack

  • US 5,984,953 A
  • Filed: 05/21/1998
  • Issued: 11/16/1999
  • Est. Priority Date: 05/21/1998
  • Status: Expired due to Fees
First Claim
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1. A disposable heating device comprising:

  • a disposable container having at least one liquid-impermeable first zone and at least one liquid-impermeable second zone;

    a separator disposed between the at least one first zone and the at least one second zone, the separator being operable to provide communication between said zones;

    a mixture comprising a primary fuel, a preformed stiffenable gel, and a vaporizable solvent in the at least one second zone; and

    a substantially solid and particulate oxidizing agent in the at least one first zone, said oxidizing agent being embedded and dispersed throughout solid pieces of a binding agent dissolvable in at least one of said solvent and said primary fuel,wherein communication between the first and second zones allows mixing of the contents therein and at ambient temperature initiates a primary exothermic chemical reaction producing heat in said container,wherein the dissolvable binding agent dissolves during said exothermic chemical reaction to controllably expose said particulate oxidizing agent at a predetermined rate,wherein the container includes a vapor space and a condensation surface above the contents of the zones after communication between the zones is provided,wherein the vaporizable solvent vaporizes into the vapor space and condenses on the condensation surface when the temperature of the device approaches a predetermined maximum temperature during operation of the device, causing stiffening of the gel, andwherein the amount of said preformed stiffenable gel is sufficient to prevent said exothermic chemical reaction from causing the temperature of the container to overshoot the predetermined maximum temperature during operation of the device.

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