Verfahren und Vorrichtung zur Durchmesserkontrolle von klaren extrudierten Schläuchen

摘要

A method and apparatus for controlling the diameter of a clear extruded molten tube 44 wherein the extruded tube contains a volume of a clear liquid 48 and the level of the liquid is indicative of the tube diameter so the level rises as the tube diameter decreases. A light beam 32 passing through the tube is refracted from a straight line path when the liquid level rises above the level of the beam. The refracting of the beam in turn triggers the introduction of air into the extruded tube to increase the diameter of the extruded, molten tube.