Application of side folds in lay=flat tubing - reduced friction between blown tubing and folding equipment is obtd. by producing air cushion between tubing and side guides

摘要

The side folds in a tubular flat sheet process are applied by a wedge-shaped device just prior to the flattening rollers. The wedge-shaped frame converges towards the central plane of the equipment. On the opposing faces of the frame chests are constructed the inner faces of which have a multiplicity of holes. Air is blown into the outer faces of the chests and exits via the small holes on the inner faces. An air cushion is therefore created between the inner faces and the tubular film. ADVANTAGE - The almost frictionless equipment reduces clinging of the film to the guiding equipment. The air cushion produces better cooling.