The outer casing of the metal tubular electric heating element adopts a seamless metal tube, and a spiral type electric resistance wire is arranged in the axial direction of the tube, and a non-metal oxide (magnesium oxide powder) having good insulation and good thermal conductivity is filled between the gaps.
It can be installed in an air passage to heat the air, or it can be immersed in water or other liquids to heat water or other liquids, or it can be directly placed in a solid metal to heat the metal.