| 摘要 |
Continuous production of bi-axially oriented plastic tubing includes extruding a blank, heat treating the blank to orient the plastic, radially expanding the blank into a tube and then gauging and cooling the tube. An axial traction force applied to the tube is monitored so the applied force is kept substantially constant. Independent claims are included for the following: (a) A plastic tube made as above. (b) A production line for plastic tube has an extruder, temperature controlled tank(s) for molecular orientation of the extruded plastic, a radial dilator, a Preferred Features: The traction force is controlled by measuring the force applied to the tube, the internal pressure of the tube and/or depression of the tube at the gauging device. A tube traction device is downstream of the gauging device and cooling devices. Two spaced apart flexible plugs within the expanded blank/tube define a sealed chamber within it. |
