Device with a controllable main cooling gas ring with a rectifier unit and an auxiliary cooling gas ring

摘要

The device has a flow detecting arrangement (16) with a circumferentially divided flow channel, and a cylindrical valve (26) for changing a passage cross-section of the channel. An auxiliary cooling gas ring (21) is arranged upstream to a main cooling gas ring (11) along a manufacturing direction of a blow film. A circumferentially divided, radially aligned flow channel (24) is provided such that a flat valve (29) changes a passage cross-section of the latter channel. A supply pipeline (66) causes the valves to change the passage cross sections of the channels of the cooling gas rings.