| 摘要 |
1532929 Tubular film; cooling extruded film MOBIL OIL CORP 7 July 1977 [30 Aug 1976] 28601/77 Heading B5B and B5A In a blow extrusion method for forming tubular film the blown film is passed through a cooling sequence comprising a series of pairs of cooling gas jets in convergent or parallel flow paths in each pair. Tube bubble 12 is moved through a plurality of superposed air plenum chambers 18 each provided with a ring member 20 the inner surface of which is maintained at an angle to provide a smooth conical configuration, Fig. 3, shows that air passing along 18 through parallel annular slots 30 and 32 (converging air passages 26 and 28 are similarly shown in Fig. 2, not reproduced) impinges on the external surface of the tube 12 and the upward and downward flows of air from 32 and 30 oppose each other, causing an area of pressure between face 34 and the surface of 12. The balance between such external pressure and the internal pressure in the blown tube stabilizes the vertical path of the blown film and eliminates flutter at high film speeds. Air is withdrawn between each pair of rows of gas jets. |
