| 摘要 |
PURPOSE:To eliminate the possibility of film being fused on the hot air supply nozzle or clip in an oven in order to prevent a lowering in the productivity by a method wherein, in case a lateral stretching device should be interrupted during the lateral stretching period, a cooling air is immediately sent into the oven positively. CONSTITUTION:The film F sent out from an extruder 1 is vertically drawn by a vertical stretching machine 2 and also laterally drawn by a lateral stretching device 3. To perform this stretching function, a hot air blower 4a is provided above an oven 4. An air blower 5 adapted to positively send a cooling air into the oven 4 by a motor 5a is provided in the front part of the oven 4 and its air supply opening 5b is provided in a preheating chamber 4b, i.e., at the entrance part of the vertically stretched film F. In case the lateral stretching device should be interrupted due to the trouble, the cooling air is immediately sent into the oven 4 positively to rapidly decrease the temp. of the film F and of the inside of the oven 4 with the accompanying rapid cooling of the hot air supply opening and in doing so to prevent the film from fusing on the hot air supply opening or the roll of the lateral stretching device. |
