APPARATUS FOR CONVEYING PLASTIC MATERIAL

摘要

A screw conveyor for an extruder comprises a single rotatable screw which has a countercurrent first portion having a countercurrent land with interruptions therein for partially backfeeding plastic material to provide a turbulent current of plastic material. The screw conveyor has a second portion with two threads, one of which has radial grooves therein, to divide the current into partial streams flowing backwards but having further travel under a substantially steady forward feed to compact and intensively mix the plastic material.