| 摘要 |
946,837. Tubular films. INTERNATIONAL DEVELOPMENT CO. OF NATIONAL DISTILLERS & CHEMICAL CORPORATION S.A. May 8, 1961 [May 20, 1960], No. 16671/61. Heading B5B. A tube of adjustable wall thickness is extruded from the inner or outer periphery of an annular extrusion orifice formed by two spaced plates, one of which is attached to a stud plate by a ring of bolts arranged alternately for increasing and decreasing the width of the orifice. As shown, plastic is forced inwards through a conduit 11a to an annular chamber 4a and an annular orifice 15 formed between plates 1 and 2, plate 2 carrying a stud plate 6 and two series of bolts 7 and 8 for decreasing and increasing respectively the width of the orifice. Controlled inflation is effected by passage of air through inlet pipe 53 (Fig. 3), excess being bled off through exhaust 16 if necessary. The tube is cooled by chill ring 61. In a modification (Fig. 4, not shown), plastic is forced upwards and outwards, the tube being cooled by an upwards stream of air close to the annular orifice. |
