Screw-type extruder

摘要

An extruder for processing of thermoplastics has a housing (1) in which a screw is pivotally supported. A land (5) which runs in a helical line protrudes from the core (4) of the screw. There is at least one ventilation opening in the housing in which the screw is pivotally supported. The land (5) of the screw at least in the area of the ventilation opening has an active flank, i.e. one which points toward the discharge end of the extruder and which encloses with the axis of the screw an acute angle such that at least in areas it is set back relative to a radial plane which passes through the outside edge (14) of the active flank (10). This prevents the plastic which is to be processed in the extruder from being pressed to the outside and clogging the ventilation opening.