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.
