APARATO Y METODO PARA RESTRINGIR LA EXPANSION DE UN TUBO GIRATORIO DE MATERIAL EXTRUIDO

• Main Authors: JOHN W. LOUKS, EUGEN WILL, RONALD P. SWANSON, STEVEN J. LENIUS
• Format: Patent
• Language: Spanish
• Published: 01.10.1992
• Edition: 5
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; PERFORMING OPERATIONS; PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCESIN A PLASTIC STATE; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

A constraining structure for an open tube apparatus for continuously producing a rotating elongate strip of material is disclosed. The constraining structure controls expansion of an extruded blown film tube to a desired outer diameter range after the tube is formed. The constraining structure includes a casing positionable around the tube, and an annular sleeve in the casing having a generally cylindrical central passageway adapted to receive the tube to permit movement of the tube along its longitudinal axis in a downline direction. The casing and the sleeve walls define a gas chamber with pressurized gas separate from the passageway. The gas layer along the inner surface of the sleeve is at a sufficiently large pressure to constrain the tube to the desired outer diameter while the tube solidifies and to prevent the tube from contacting the sleeve.