Abstract: A foil-blowing apparatus has its external cooling nozzles vertically and/or radially adjustable relative to the transition region between the neck of the thermoplastic tube and the blown foil balloon to enable thickness errors to be eliminated.

Abstract: An apparatus for blow extruding a tubular plastic foil has a nozzle having an upwardly open annular mouth generally centered on a longitudinal axis for upwardly extruding a tubular plastic strand and an inner tube extending upward from the nozzle within the mouth thereof, having an upper end spaced axially from the mouth, and formed between the upper end and the mouth with at least one radially throughgoing hole. A stabilizer head carried on the inner-tube upper end is formed with passages having inner ends opening into the inner tube at the upper end thereof and outwardly directed outer ends. An outer tube surrounding the inner tube defines an inner longitudinal passage therewith, extends upward from the nozzle within the mouth thereof, and has an upper end above the hole and below the inner-tube upper end.

Abstract: In a foil blowing apparatus, the distribution of singularity in the flattened foil tube over the length of a roll in which the tube is coiled are distributed by a fold shifting device above the squeezing rollers at the top of the foil blowing unit. The fold shifting device has three sets of pivotal planes each formed by a deflecting roller and a turning bar and oriented so that the maximum angle between each approaching stretch of the flattened tube and a perpendicular to the turning bar is 30.degree. and the maximum angle of each departing stretch and the perpendicular to the turning bar is 30.degree..

Abstract: A device for feeding film-blowing air into the plastic tube and film bubble of a blowing head is connected to the film-blowing head and includes between the foot side and head side outlets thereof, with at least one intake device and at least one further outlet in spaced relationship and with matched flows to stabilize the tube and the neck formed between the tube and the expanding bubble.