Control apparatus for producing uniform thickness corrugated tubing

摘要

Apparatus and method for producing thermoplastic corrugated tubing having substantially uniform thickness throughout comprises extruder and step of forming hollow smooth-walled extrudate. Corrugating structure immediately adjacent extruder is arranged to receive extrudate and to form corrugations therein. Such structure includes continuously moving cooperating mold blocks configured to form alternating annular peak portions, valley portions and interconnecting side wall portions in extrudate when it is blown into intimate engagement with configured mold blocks. Thickness of extrudate being corrugated is controlled to provide relatively thin extrudate portions during formation of annular valley portions and relatively thick extrudate portions during formation of annular peak and interconnecting side wall portions.