Vented single stage barrier screw with a gas vent hole and axial bore in the screw for venting gases

摘要

A barrel contains an extruder conveying screw which has a drive end, a feed section, a melting section and a pumping section wherein the screw has a vent hole located from 0 to 2 screw diameters from the beginning of the feed section. An axial bore in the screw vents gases from the barrel through the gas vent hole and into the axial bore.