Worm press for kneading and displacing plastic masses

Claim 1

A WORM APPARATUS FOR PLASTIFYING AND DE-GASSING PLASTIC MASSES COMPRISING A HOUSING DEFINING AN AXIAL PASSAGE COMPRISING A SUBSTANTIALLY CYLINDRICAL INLET PORTION, A TRANVERSELY WIDENED DE-GASSING CHAMBER AND A SUBSTANTIALLY CYLINDRICAL DELIVERY PORTION, A WORM MEMBER ROTATABLY SUPPORTED IN SAID AXIAL PASSAGE AND HAVING A SCREW-THREADED PLASTIFYING PORTION WITHIN SAID DETION, A SCREW-THREADED SQUEEZING PORTION WITHIN SAID DEGASSING CHAMBER, AND A SCREW-THREADED DELIVERY PORTION WITHIN SAID DELIVERY PORTION OF THE AXIAL PASSAGE IN SAID HOUSING, THE SCREW-THREADS OF SAID WORM MEMBER IN SAID SQUEEZING PORTION HAVING A FORWARD FLAN FORMING A SMALLER ANGLE WITH THE AXIS OF THE WORM MEMBER THAN THE REAR FLANK AND THE OUTER DIAMETER OF THE SAID SCREW THREADS WITHIN SAID DE-GASSING CHAMBER FORMING A NARROW GAP WITH THE WALL OF SAID DE-GASSING CHAMBER OVER A SUBSTANTIASL PORTION OF ITS PERIPHERY WHEREBY ON EAWCH REVOLUTION OF THE WORM MEMBER PART OF THE MATERIAL IN ITS GROOVE IS FORCED BACK THROUGH SAID GAP IN A THIN LAYER FROM A ZONE OF LOCAL HIGH PRESSURE TO A ZONE IN WHICH DE-GASSING VACUUM IS EFFECTIVE FOR REMOVING GASES PRESENT IN SAID THIN LAYER.