Abstract: The invention relates to a blow head for producing blown tubular films from thermoplastic materials. Films produced by conventional blow heads often have dull strips or wavy areas, the so-called spiral strips. The aim of the invention is to avoid these negative film properties. For this purpose, the blow head comprises a plurality of annular gap-shaped melt channels arranged concentrically around the center axis of the blow head, the spiral distributor of the inner melt channel being arranged on the inner limiting wall in relation to the center axis of the blow head and the spiral distributor of the outer melt channel being arranged on the outer limiting wall in relation to the center axis of the blow head.

Abstract: The invention relates to a blow head for producing blown tubular films from thermoplastic materials. Films produced by conventional blow heads often have dull strips or wavy areas, the so-called spiral strips. The aim of the invention is to avoid these negative film properties. For this purpose, the blow head comprises a plurality of annular gap-shaped melt channels arranged concentrically around the center axis of the blow head, the spiral distributor of the inner melt channel being arranged on the inner limiting wall in relation to the center axis of the blow head and the spiral distributor of the outer melt channel being arranged on the outer limiting wall in relation to the center axis of the blow head.

Abstract: In order to make the thickness and strength values uniform in an extruded foil tubing made of high density polyethylene (HDPE), in the form of a long neck, an air nozzle ring is provided at the level of the end of the long neck in addition to an outer blow ring surrounding the ring nozzle of the blow head. The rate of air flow through the nozzles of the air nozzle ring is controlled dependent on a rotating measuring device for measuring the thickness of the foil which is located above the expansion portion of the foil tubing. The cooling effect of the outer blow ring is preferably twenty times greater than that of the air nozzle ring. To stabilize the foil bubble, an inner pin is provided at the level of the end of the long neck.

Abstract: A take-away device for a flattened tubing foil forming machine having an improved foil edge position control. The take-away device for tubing foil is formed by an extruder with a tubing blow head carrying out a blowing process. The tubing foil is flattened between a pair of squeeze rollers, which pair of rollers can reversingly turn about a vertical axis of rotation. At least two turning rods are disposed following the squeeze rollers. The turning rods are pivotable about at least one vertical axis, and have, if necessary, at least one deflecting rod. The rods are pivoted by a frame member about a horizontal axis of rotation. A winding-up device receives the flattened tubing foil from the turning rod. A measuring instrument is disposed between the final turning rod from which the tubing foil is guided to the wind-up device, and the wind-up device.