Abstract: A self-regulating PTC heater assembly and a method of manufacturing the heater assembly is disclosed. PTC heater assembly includes a plurality of positive temperature coefficient devices, a plurality of spacers located between the positive temperature coefficient devices, a pair of metallic electrodes and a heat shrink tubing surrounding the pair of electrodes, PTC elements and spacers to hold the PTC elements and electrodes in place during assembly. A metallic sheath is compressed about the heat shrink tubing to establish uniform electrical contact between the PTC elements and the electrodes, to increase the thermal efficiency of the heater and to protect the heater assembly from physical damage.

Abstract: A flexible electric heating assembly for immersion heating of highly corrosive liquids, such as electroplating solutions, includes an iron-nickel-chronium resistance element disposed within a thin-walled stainless steel tube and electrically insulated therefrom by a magnesium oxide ceramic. The tube is enclosed in a tubular casing in direct contact with the tube and formed of resilient electrical insulating material having a low surface coefficient of friction and a high resistance to heat and attacks by corrosive liquids or vapors, e.g., polytetrafluroetylene. The ends of the tube terminate withn a non-corrosive junction box located outside the liquid to be heated, and in which box the connections between the power supply and heating element terminals are made.