Patent ID: 8183503

Claim:
A reversible, submersible, encapsulated PTC heater comprising: a disc-shaped sealable housing; a central disc comprised of a sheet mineral disposed within the sealable housing and having a central bore; a plurality of cavities disposed within the central disc; a plurality of positive temperature coefficient (PTC) of resistance heating elements disposed within the cavities within the central disc; an upper electrode disc disposed upon a top side of the central disc and plurality of PTC heater elements; and a lower electrode disc disposed upon a bottom side of the central disc and plurality of PTC heater elements; wherein the upper electrode disc and the lower electrode disc each have a central bore and are configured for flexibility to make an intimate contact with a plurality of surface areas on the plurality of PTC heating elements, and configured for connectivity to an electrical power source; an upper polyimide film disc disposed upon a top side of the upper electrode disc; and a lower polyimide film disc disposed upon a bottom side of the lower electrode disc; wherein the upper polyimide film disc and the lower polyimide film disc each have a central bore and each are configured to provide an electrical insulation; wherein, the housing, the central disc, the plurality of PTC heating elements, the thin film electrode discs, and the polyimide film discs that form the PTC heater are adapted for encapsulation; and wherein the PTC heater is configured to electrically heat a medium to a predetermined temperature and to maintain the temperature of the medium.