ELECTRICALLY OPERATED HEATING ASSEMBLY

摘要

The heating element has a heat conductor in the form of a metal tube. The molten plastic is conveyed to the tube through an inflow aperture. The end of the tube that is remote from the inflow aperture is shaped into a point and has flowthrough apertures. The tube is welded in the vicinity of the point to an outer jacket made out of a material with a low specific electric resistance. Outside the welding point, there is a layer of insulation between the tube and the outer jacket. The layer is between 0.1 and 0.5 mm thick and can be made out of ceramic. The electric energy supplied to the tube is so low that the molten plastic is not subjected to thermal overload in the vicinity of the point.