Biaxial stretching pipe i.e. plastic pipe, producing method, involves expanding pipe by excess pressure and molding pipe by calibrating outlet until biaxial stretching pipe is produced without inserting mandrel to set counter pressure

摘要

The method involves extruding a plastic strand by an extruder (1) and performing the strand to an extruded pipe (3) by a tool (2). The strand is calibrated and cooled below a glass transition range of plastic in a calibrating cooling bath (4). The pipe is pulled by an outlet (5), where the preformed pipe is heated by a radiant heater or a hot air blower until a plastic mass (6) has reached the range. The pipe is expanded by excess pressure and molded by a circulated calibrating outlet (8) until a biaxial stretching pipe (7) is produced without inserting a mandrel to set a counter pressure. An independent claim is also included for a device for producing a biaxial stretching pipe.