Cooling air feed system for annular extrusion die producing tubular film includes segmented flow channels, each with temperature control elements

摘要

A nozzle housing surrounds the inflating tube and has a cooling air inlet connected by a flow channel with an outlet onto the tube. The channel and outlet are divided into air guiding segments (KR), each of which has a by-pass channel incorporating an independently controllable element. A nozzle housing surrounds the inflating tube (F) and has a cooling air inlet (60) connected by a flow channel (62) with an outlet (68) onto the tube. The channel and outlet are divided into air guiding segments (KR), each of which has a by-pass channel (600) incorporating an independently controllable element (66) for varying the cooling air temperature in it in response to any deviation of the tube thickness profile from a set value.