METHODS AND INSTALLATIONS FOR MANUFACTURING BIAXIALLY ORIENTED TUBING AND THE TUBING ITSELF

摘要

THE PRODUCTION OF A BIAXIALLY ORIENTED TUBE (10) FROM THERMOPLASTIC MATERIAL, WHEREIN A TUBE IN PREFORM CONDITION IS EXTRUDED FROM THERMOPLASTIC MATERIAL USING AN EXTRUDER HAVING AN EXTRUDER DIE HEAD WITH AN INNER DIE MEMBER THAT FORMS A LUMEN IN THE TUBE IN PREFORM CONDITION. THE TUBE IN PREFORM CONDITION IS SUBJECTED TO A TEMPERATURE CONDITIONING. USE IS MADE OF A EXPANSION DEVICE COMPRISING A NON-DEFORMABLE EXPANSION PART (20B, 200B) HAVING A GRADUALLY INCREASING DIAMETER TO A MAXIMUM DIAMETER, WHICH EXPANSION PART IS CONTACTED BY THE TUBE AND EXERTS AN EXPANDING FORCE SO AS TO BRING ABOUT EXPANSION OF THE TEMPERED TUBE IN CIRCUMFERENTIAL DIRECTION. THE METHOD COMPRISES DRAWING THE TEMPERED TUBE OVER THE EXPANSION DEVICE USING A DRAWING DEVICE, IN SUCH A MANNER THAT SAID TUBE IS TRANSFORMED FROM A TUBE IN PREFORM CONDITION INTO A BIAXIALLY ORIENTED TUBE WITH THERMOPLASTIC MATERIAL WHICH IS ORIENTED IN AXIAL DIRECTION AND IN CIRCUMFERENTIAL DIRECTION OF THE TUBE. FIGURE 2