Extruder head has an inner cylindrical mantle with spiral grooves to carry the molten material from feed drillings within a mantle secured to the foot with a shrunk sealing ring

摘要

The extruder head (1), and preferably a film blowing head, has an inner cylindrical mandrel (2) which has at least one drilling (6) at the foot zone for the feed of the molten material for extrusion. A sealing ring (7) is shrunk to the mandrel (2) near its foot (3). A cylinder mantle is mounted over the ring (7), in a sealed fit which, with the mandrel (2), forms a ring channel (10). The mandrel (2) has a number of spiral grooves (4), leading from the foot end (3), with a reducing depth towards the jet gap (5) and closed towards the foot (3). The drillings (6) carry the molten material into the leading ends of the grooves, and the starting zone for the grooves is sealed by a sealing ring (7) shrunk onto the mandrel (2) where its surface carries no grooves. The mandrel foot (3) and the ring (7) give a common plane for a radial ring surface, together with the mantle (11). The mantle (11) is clamped with the ring (7) to the ring surface (8) of the foot by expansion screws.