EXTRUDER HEAD FOR MAKING POLYMERIC BAG FILM

摘要

1518394 Cooling extruded tubular film PLASTUND ELASTVERARBEITUNGSMASCHINEN-KOMBINAT KARL-MARXSTADT VEB 15 April 1976 [23 April 1975 18 Nov 1975] 15549/76 Heading B5A A tubular plastics material film which is extruded from a passage 1 of a die assembly which rotates about the axis of the film during extrusion, is internally cooled and inflated by continuously circulated air which is delivered through concentric inlet and outlet passages 24, 25 of the die mandrel 5 from stationary annular fluid delivery and exhaust manifolds 16, 17, surrounding the die assembly, via circumferentially spaced respective passages 23, 26, extending radially through die webs 11 between which the plastics material flows to the passage 1 from an inlet passage 3. The webs 11 are formed by die members 12, 13, on which the manifolds 16, 17 are engaged at metal seals 20, and the air is delivered to and from the manifolds 16, 17 by air blowers, at circumferentially spaced inlets and outlets 28, 29, of which the inlets 28 and the inlets to passages 23 are preferably of the same shape. and area, and of relative numbers, e.g. seven and six, such that one or two of the inlets 28 and passages 23 are always in register, to avoid pulsations in the air supply. A heat exchanger may be provided in the supply to the inlets 28. The channels 23 and 24 are also relatively staggered. The members 12, 13 each comprise inner and outer members 121, 1211, and 131, 1311, between which are provided an electrical heater 14 from which electric lead cables pass through a groove 15 in the outer ring 1311 to slip ring contacts. The passages 23, 24 and 25, 26, are provided with heat insulation.