Film size control apparatus for the blown film process

• Main Author: BEHR; R. DOUGLAS
• Format: Patent
• Language: English
• Published: 09.11.1976
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; PERFORMING OPERATIONS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

Apparatus for regulating the flow of refurbishing gas or air internally to tubular film produced by the blown film process, comprising a pair of opposed arm means or arms adapted to physically contact and sense growth or diminishment in the size of the film, as determined by the spacing between the arms, the arms being independently pivotable preferably about a common axis, or alternately parallel axis closely spaced to approximate a common arc of movement, a gas flow regulating valve comprising a pressurized gas line carried by one arm, at which vicinity it is interrupted to define a gap across which the gas stream flows prior to entering the film, a flow blockage valving means comprising preferably a valve plate fixed to the opposite arm, and having changing position in said gap responsive to relative movement between the arms, the valve plate defining an opening of tapered or variable width, which depending on alignment, partially hindered alignment, or non-alignment with the gas stream, increases or lessens the flow rate as required to maintain a control or predetermined film size.