SIZING APPARATUS

摘要

A sizing sleeve for controlling the diameter of plastic tube includes pressurised sizing sleeve portions (10) in which fluid is injected under pressure about the tube circumference to form a lubricating layer. Drainage zones (12) axially separate and isolate adjacent pressurised portions to allow independent temperature and pressure control. Each pressurised portion has flow stabilizing means (28) reducing variations in flow responsive to changes in the lubricating layer pressure. The stabilising means may comprise a high pressure fluid source and high pressure drop constriction means comprising fine apertures (56), which may be formed as grooves milled into end surface of abutting sizing sleeve segments (30).