Abstract: A dual plate heater provides two parallel temperature self-regulating heater plates or wire mesh comprising ferromagnetic material with one or more electrically energized coils parallel to and located between the heater plates which coil(s) when energized by a constant current or by an otherwise controlled current heat the plates to their Curie temperature or temperatures. The coil may be a flat spiral of thin conductive (copper) wire embedded in a thin layer of a heat conductive, electrically non-conductive material between said plates whereby heat energy generated in the coil is supplied to the heater plates. The dual plate heater may be employed to heat plastic pipes to their butt welding temperatures after which the heater is removed to the ends of the pipes to be joined are brought into contact under pressure. The dual plate heaters may also be employed in other arrangements such as shelves in a dispensing machine.

Abstract: A dual plate heater provides two parallel temperature self-regulating heater plates or wire mesh comprising ferromagnetic material with one or more electrically energized coils parallel to and located between the heater plates which coil(s) when energized by a constant current or by an otherwise controlled current heat the plates to their Curie temperature or temperatures. The coil may be a flat spiral of thin conductive (copper) wire embedded in a thin layer of a heat conductive, electrically non-conductive material between said plates whereby heat energy generated in the coil is supplied to the heater plates. The dual plate heater may be employed to heat plastic pipes to their butt welding temperatures after which the heater is removed to the ends of the pipes to be joined are brought into contact under pressure. The dual plate heaters may also be employed in other arrangements such as shelves in a dispensing machine.

Abstract: A fast heating, highly efficient griddle with interchangeable griddle plates including magnetically permeable materials having Curie temperatures which may be the same or different to provide different cooking temperatures is provided. The plates are formed as a balanced composite structure which mitigates bending when the magnetically permeable materials are heated to their Curie temperatures. Induction coils provide sufficient energy to heat the plates to their effective Curie temperatures in the presence of loads and maintain a uniform cooking temperature across the griddle plate to within less than one inch of the plate edges. The plates may be placed in an enhanced idle condition at cooking temperature by placing a cover over the plates or region of a plate not in use. Increased efficiency is achieved due to an insulator blanket placed between the griddle plates and coils.