| 摘要 |
1,102,078. Extruding polypropylene tubing. B. X. PLASTICS Ltd. 11 March, 1966 [26 March, 1965], No. 12841/65. Addition to 1,059,346. Headings B5A and B5B. The apparatus described in Specification 1,059,346 for producing extruded isotatic polypropylene tubing is modified by having a feed opening 9 which allows the formation of a substantially closed circuit for the quenching liquid. This liquid preferably has a temperature range between 1 and 20‹ C. within sleeve 6. Further, former discs 15 may vary in diameter, e.g. increase in diameter downstream, and an additional shaping disc (not shown) may be placed above the level of the liquid in bath 5. Discs 15 may be perforated so that the pressure of the air supplied below the former via conduit 18 may be regulated. |
