The cartridge heater is a high-quality
seamless metal tube, with electrothermal
alloy wire (nichrome wire, ferrochrome
wire) evenly twined around the the central
axis in the tube. The gap in it is
compactly filled with oxydic magnesia with
fine insulativity and thermal conductivity,
and the nozzle is sealed with silica gel or
ceramics. This kind of metal armored
electrothermal element has the function of
heating gases, molds and a variety of
liquids.
