Method and apparatus for controlling size of extruded tube

US4325897A · kind A · utility

Inventors

• Ludwig Zerle · Bogen, DE
• Klaus Scharm · Augsburg, DE

Key dates

• Filing date: May 12, 1980
• Grant date: Apr 20, 1982
• Expiry date: May 12, 2000

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B29C2948/92923
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

An assembly at an extruder for controlling the width of a two-layer web flattened from a tube extruded from a rotating or oscillating head of the extruder comprises monitors for detecting the velocity and edge-positions of the web upon transport thereof away from the extruder. A control circuit calculates the deviation of the actual web width from a predetermined width and emits a correction signal relayed via a stationary infrared-radiation transmitter and a receiver on the extruder head to valves controlling the pressurization of the extruded tube by a blower also mounted on the extruder head.