Method and apparatus for extruding thermoplastic material

Claim 1

IN A METHOD OF EXTRUDING THERMOPLASTIC MATERIAL FROM AN ELASTIC MELT EXTRUDER HAVING A FIXED PLATE AND A ROTATABLE PLATE PROVIDED WITH AXIALLY SPACED, CONFRONTING FACES DEFINING A MELT CHAMBER THEREBETWEEN, RELATIVE ROTATION OF SAID PLATES CENTRIPETALLY ADVANCING MATERIAL THROUGH SAID CHAMBER IN A SPIRAL PATH FOR ISSUANCE IN A PLASTICIZED STATE THROUGH AN EXTRUSION ORIFICE FORMED IN ONE OF SAID PLATES, THE STEPS OF ADVANCING UNPLASTICIZED MATERIAL UNDER POSITVEI PRESSURE EXERTED BY A ROTATING SCREW FROM A SOURCE OF SUCH MATERIAL EXTERNAL TO SAID CHAMBER IN A DIRECTION PARALLEL TO THE AXIS OF RELATIVE ROTATION OF SAID PLATES, PASSING SAID UNPLASTICIZED MATERIAL THROUGH AN OPENING IN SAID FIXED PLATE OPPOSITE A PORTION ONLY OF THE PERIPHERY OF SAID ROTATABLE PLATE AND IN SAID DIRECTION INTO THE MELT CHAMBER, AND DEFLECTING SAID MATERIAL FROM SAID DIRECTION AND SCREW INTO SAID SPIRAL PATH ONLY AFTER SAID MATERIAL IS IN SAID CHAMBER BY ROTATING SAID ROTATABLE PLATE.