DEVICE FOR EXTRUDING THERMOPLASTIC MATERIAL

摘要

A device for extruding thermoplastic material has an extruder housing (1) in which an extrusion worm (2) operated by a drive system is fitted so as to rotate about its axis. The extruder housing is divided into two chambers (8, 9) by a return thread (7) sealing the circumference of the worm against the housing wall. One chamber (8) has an inlet (3) for the material to be extruded and the other (9) has an outlet (5) and outgassing apertures (17) at an axial distance therefrom. Both chambers are interconnected by at least one channel (11) in which is fitted a melt filter (14). Viewed in the direction of flow of the plastic material to be processed, the outgassing apertures (17) are at a distance from the openings (16') of the channels (11) into the chamber (9). In this region the extruder worm (2) thread is shaped to form a pressureless region (18) so that the filtered plastic material is given the time to outgas. This favours outgassing.