Cooling method and apparatus.

摘要

Apparatus and method for cooling an extruded blown plastics film in which the interior surface of the thin film bubble is contacted with an anhydrous cooling gas which does not contain water vapour thereby to cool the extruded film and form a spent gas employs a mixing chamber 72 having a first inlet 66 for liquid cryogen such as liquid nitrogen and a second inlet 68 for spent gas in order to form the cooling gas. The mixing chamber 72 may form part of an ejector 74 which may be located internally of or outside the bubble itself. Improved film production rates are made possible.