Abstract: Device for heating a blown film web, inflated into a blown film bubble between a pair of forward draw rolls and a pair of take off rolls, comprises a frame mounted, driven pair of forward draw rolls and an opposite, stationarily mounted, driven pair of take off rolls for the blown film web hauled off the inflated bubble. Furthermore, there are collapsing mechanisms and mechanisms for inflating and heating the blown film web. To feed the correct amount of heat to the inflated web independently of its diameter, the heating devices comprise heating elements, which are arranged concentricly around the axis of the inflated blown film web and which can be moved toward and away from the blown film web by means of regulating drives in the radial direction.

Abstract: In a process of manufacturing oriented tapes, which have been folded at least once, from synthetic thermoplastics, particularly for use in the manufacture of high-strength woven fabrics, the tapes are folded on themselves before they are wound on the spool used for their further processing.

Abstract: Z-shaped folds are formed in a tubular film and the latter is inserted into a woven tubing as the latter is woven and collapsed in a circular loom. The tubular film is squeezed between pairs of pinch rollers and is then inflated to form a bubble, which is supported by annular surfaces at the weaving ring and at a distance from the latter so that the bubble bulges between the annular surfaces so as to form an annular bead. A Z-shaped annular fold is formed in that tubular film in that edge portion of said annular bead which is remote from the weaving ring is pushed into the latter. For the fixation of the Z-shaped folds e.g., at the portions which will subsequently form the rims at the open ends of the bags to be made, it may be desirable to apply adhesive to the tubular film above the Z-shaped folds and to force said adhesive-coated portions against the inside surface of the surrounding woven tubing.

Abstract: A flattened tube of continuous film is opened up by being fed over a mandrel which is floatingly disposed within the tube. As the tube is passing over the mandrel, which serves as a backing, a layer of reinforcing tapes is helically wound thereabout and fixed thereto, whereafter the tube is flattened again. Each side of the tube is then successively provided with a layer of parallel further reinforcing tapes which are anchored by a plastics covering layer that is extruded thereon and pressed thereto.