Method and apparatus for extruding plastic material

Claim 1

IN AN ELASTIC MELT EXTRUDER HAVING A PAIR OF RELATIVELY ROTATABLE PLATES HAVING AN AXIS OF ROTATION AND DEFINING A MELT GAP THEREBETWEEN AND MEANS TO SUPPLY NONPLASTICIZED THERMOPLASTIC MATERIAL TO THE PERIPHERY OF THE GAP FOR CENTRIPETAL FLOW THROUGH THE GAP TO ISSUE THEREFROM AT A PREDETERMINED RELATIVELY LOW OUTPUT PRESSURE, THE IMPROVEMENTS OF A RESERVOIR FOR PLASTICIZED MATERIAL COAXIAL WITH THE AXIS OF RELATIVE ROTATION OF SAID PLATES AND HAVING AN OUTLET ORIFICE, ACTUATABLE FIRST VALVE MEANS CONTROLLING SAID ORIFICE, SAID FIRST VALVE MEANS BEING OPENABLE TO ACCOMMODATE THE FLOW OF MATERIAL THROUGH SAID ORIFICE AND CLOSABLE TO PREVENT SUCH FLOW, ACTUATABLE SECOND VALVE MEANS OPENABLE TO ACCOMODATE THE FLOW OF PLASTICIZED MATERIAL FROM SAID GAP INTO SAID RESERVOIR AND CLOSABLE TO PREVENT SUCH FLOW, A PRESSURIZING RAM LOCATED IN SAID RESERVOIR AND MOVABLE THEREIN (1) IN A FIRST DIRECTION TO EXPRESS PLASTICIZED MATERIAL FROM SAID RESERVOIR THROUGH SAID ORIFICE AT A PRESSURE DIFFERENT FROM SAID OUTPUT AND (2) IN A SECOND DIRECTION TO ACCOMMODATE THE ENTRY OF PLASTICIZED MATERIAL AT SAID OUTPUT PRESSURE INTO SAID RESERVOIR FROM SAID GAP, ACTUATABLE POWER MEANS FOR (1) MOVING SAID RAM IN SAID FIRST DIRECTION AND (2) RESISTING MOVEMENT OF SAID RAM IN SAID SECOND DIRECTION, AND CONTROL MEANS CORRELATING ACTUATION OF SAID POWER MEANS, SAID SECOND VALVE MEANS AND SAID FIRST VALVE MEANS (1) TO CLOSE SAID FIRST VALVE MEANS AND TO OPEN SAID SECOND VALVE MEANS TO FILL SAID RESERVOIR FROM SAID GAP AND AGAINST THE RESISTANCE OF SAID POWER MEANS, AND THEN (2) TO OPEN SAID FIRST VALVE MEANS AND TO CLOSE SAID SECOND VALVE MEANS WHEN SAID POWER MEANS IS ACTUATED TO MOVE SAID RAM IN SAID FIRST DIRECTION TO ISSURE MATERIAL FROM SAID RESERVOIR WITHOUT BACKFEEDING THE MATERIAL TO SAID GAP.