The structure of electric heating element include internal and external, the choice of external material is mainly for the heating tube working environment, and the internal material determines the quality of the heating element itself.
Insulation filling material between electric heating pipe and electric heating wire is multipurpose caustic magnesium, crystalline magnesium oxide, alumina and clean quartz sand, etc., they have high insulation performance and electrical strength.They have good thermal conductivity and are generally required to have a thermal conductivity greater than 0.15 Kcal /cm•h•℃.They should have similar line expansion coefficient with electric heating wire, but also good heat resistance and shock resistance;At room temperature and high temperature does not interact with the electric heating wire or tube.
Electric heating element sealing material is mainly to make the insulation filler not easy to absorb water vapor in the environment, to ensure that the electric heating element has good insulation performance.Commonly used sealing materials include paint film, such as silicone paint, epoxy wax, methyl silicone oil, silicone rubber, single glass, composite glass, enamel glass, and sealing plug made of ceramic or rubber, etc.
