VERFAHREN UND VORRICHTUNG ZUR HERSTELLUNG VON IN ZWEI RICHTUNGEN ORIENTIERTEN, WAERMESCHRUMPFENDEN SCHLAUCHFOLIEN

摘要

In the process hose (1) extruded from polyethylene or ethylene copolymer, then reticulated, is led through a liquid bath (2), the temperature of which is approximately the same as the crystalline melting point of the hose material. An air bubble is blown from the hose emerging from the bath between two pairs of closing rolls (3, 7) and, during continuous expansion of the bubble, the extent of the expansion is controlled with deformation elements (10) arranged parallel or at variable angle to the direction of progress of the hose, the size of the bubble representing 50-500% longitudinal and transverse expansion in relation to the unexpanded hose. The hose is then passed via baffle plates (6) to the second pair of rolls (7). The apparatus enables increased safety and improved dimensional stability.