| 摘要 |
An internal cooling air supply assembly is provided for supplying cooling air to the interior of an extruded tubular plastic film after the film has been extruded from an annular die at an elevated temperature. The air supply assembly has a lower annular member mountable on an annular die so as to be within extruded tubular plastic film as the film leaves the die, the die having an air supply passage to supply cooling air to the interior of the lower annular member and an air removal passage including an air removal chimney extending upwardly from the die through the lower annular member to remove air from the interior of the tubular plastic film. Intermediate and first upper annular members are positionable above the lower annular member with the air removal chimney extending upwardly therethrough. The lower, intermediate and first upper annular members form an upwardly and outwardly inclined sidewall through which first and second cooling air outlets pass, and the sidewall substantially conform in shape with and extends relatively close to the interior of the extruded plastic film as the film leaves the die. Cooling air is directed onto the interior of film from the first and second chambers through the first and second cooling air outlets respectively, the cooling air outlets being sized to cause cooling air to be directed onto the interior of the film at a greater rate from the second cooling air outlet than from the first cooling air outlet.
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