| 摘要 |
PURPOSE:To hold a bubble stably by a pneumatic pressure and improve a cooling effect, by arranging the cooling air blasting nozzles at a plurality of the stages ranging from the position of a frost line to a stabilizing plate and adjusting the distance between the opening tip of the nozzles and the bubble finely. CONSTITUTION:The thermoplastic resin tubular film 2 extruded from an extrusion die 1, being inflated by blowing an air in its inside, is cooled by a first air cooling ring 3. Then, a cooling air is blasted to the film 2 between from right before the position of a frost line to the stabilizing plates 8, 8' by the second cooling rings 4, 5, 6 rotating around a bubble, thereby the cooling and the stabilization of the bubble are done. |
