This type of heater is called Sheath heater， because the structure of a metallic pipe protects the heating wire is similar to a sheath that protects a sword。
Principle
When energized, the heat generated from heating wire will be transferred to the metal tube surface via the insulated layer made of Magnesium oxide, also a perfect thermal conducting material, that is how a good heating element works。
Structure
A coiled heating wire is inserted in the center of a metallic pipe, and the gap is filled with electrically insulating material MgO (magnesium oxide, which is also called magnesia) at high density。
Features
Can be immersed directly in liquid to heat it。
Can be in close contact with metal (for welding, brazing, casting and/or stake-in) directly。
Metallic protecting pipes (pipe materials) may be selectable according to the types of objects to be heated。
High mechanical strength。
Can be bent and formed freely。
Available for high-output operations。
Capable of heating in low-temperature (such as freezing prevention and defrosting) and high-temperature ranges。
Features superior durability, cleanliness and safety。
