摘要 |
An apparatus is provided for controlling the flow of air for external cooling of a tubular film issuing from an extruder head. To ensure that the flow of the air for external cooling to the point at which the tubular film begins to expand can be controlled regardless of the distance from that point to the extruder head, flow-directing flaps are evenly distributed around the tubular film and are displaceable along the tubular film. |