| 摘要 |
In a film blowhead for making tubular plastics film, internal cooling air is supplied through a central aperture in the blowhead to superposed cooling air supply rings which support the film on the inside and have outlet apertures facing the film as well as apertures extending axially therethrough for withdrawing the heated cooling air. A central tube is provided to supply the cooling air, the tube being connected to the air supply rings by radial air passages. The annular space between the central tube and the film blowhead and the air supply rings forms an annular passage for withdrawing the heated cooling air.
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