Thin, flexible, autoregulating strap heater

Abstract

A simple, highly flexible, virtually massless, temperature autoregulating heater primarily useful for soldering has an energizing circuit that may be integral with or separate from the heater element, which element has a ferromagnetic material energized via the circuit from a constant current source whereby regulation occurs about the Curie temperature of the magnetic material. The energizing circuit may be in the form of a printed circuit conductor formed on a thin layer of Kaptan or like high temperature insulating material having the heater formed on the reverse side thereof or having a sticky substance thereon so that the energizing circuit may be temporarily adhered to the heater and removed after use. Alternatively, the energizing circuit may be formed directly on Nomex paper or the like; a quite thin paper with a sticky backing. The magnetic material may be one member of a laminate of materials having different conductive and magnetic properties whereby upon the magnetic material achieving Curie temperature, the current spreads into a layer of lower resistivity; providing large autoregulating ratios. The unusually high wattage-to-weight ratio of the heater permits large quantities of heat to be applied to a load within a very short interval which together with the ability to concentrate the applied heat to a small, well defined area permits rapid heating of the load, an essential characteristic where damage to insulation must be prevented.