IMPROVED IMMERSION HEATER WITH A POLYMER COATING OF HIGH THERMAL CONDUCTIVITY

摘要

Electrical resistance heating elements are provided which are useful in heating fluid mediums, such as air and water. The heating elements include an element body having a supporting surface and a resistance wire wound onto the supporting surface which is connected to a pair of terminal end portions. Disposed over the resistance wire, and over most of the supporting surface, is a thermally-conductive polymeric coating which hermetically encapsulates and electrically insulates the resistance wire from the fluids to be heated. This thermally-conductive polymer coating has a thermal conductivity value of at least about 0.5 W/m DEG K. Improved properties are preferably provided by ceramic powder, such as Al2O3 and MgO, and glass fiber additives.