Methods and installations for manufacturing biaxially oriented tubing and the tubing itself

摘要

An installation to produce bi-axially oriented tubing of thermoplastic material is provided with an expansion portion 200 with an upstream nose end 201 onto which the tempered preform tube 10 from the extruder is presented. The tube is expanded by fluid pressure within the chamber 210 and as it passes across the solid conical expander section 200b. The tube is drawn by a tractor mechanism downstream of the cooling region 60 of the now bi-axially oriented tubing. Fluid is supplied by fluid supply ducts 206, 207 into the respective expansion chambers between the expansion device and the tube 10. The nose end is provided with a sealing member that engages the preform tube to prevent fluid in the chamber 210 from entering the lumen of the tube upstream of the sealing member. At least one temperature sensor (not shown in this figure) is provided at or adjacent the sealing member to measure the temperature of the tube at that position so that the tempering of the preform can be closely controlled prior to expansion of the tube.