| 摘要 |
1,061,342. Tubular films. KOKOKU RAYON & PULP CO. Ltd. March 30, 1965 [Sept. 21, 1964], No. 13472/65. Heading B5B. [Also in Division G3] In a method of monitoring the diameter of an extruded, inflated tubular film prior to cooling, the diameter is sensed by optical means which act on a controlling device to adjust the flow of fluid causing inflation and thus restore the diameter of the tube to within predetermined limits. The monitoring may be effected before or after preliminary air cooling. In one embodiment, a molten tubular film, extruded from annular die (1) (Fig. 1, not shown) is cooled by air ring (3) and then cooled internally by passage over liquid-cooled mandrel (5) and externally by liquid bath (4). The film emerges from flexible baffle 11 and is collapsed between plates (12). The diameter-monitoring system comprises a stabilized light source (15) projecting a light beam of constant intensity to a photo-cell (16) and mounted such that the light beam passes tangentially to the film (14) (Fig. 2, not shown). Photo-cell (16) is connected serially to a meter relay (17), control circuit (18), and an electromagnetically operated valve located in inlet (6) of annular die (1) which controls the amount of inflating air admitted to the tube. In further embodiments, cooling mandrel (5) may be filled with a cooling liquid, e.g. silicone oil, into which air is blown, pinch rollers (13) may be mounted inside tank (94), which may be of frustoconical shape. The apparatus may also be mounted horizontally. |
