Nouvel appareil d'étirage

摘要

Apparatus for drafting synthetic yarns in a vapour after shaping the yarns comprises a boiler for producing a vapour from a liquid, a vapour treatment chamber through which the yarn is adapted to be passed while being stretched, a condenser situated above the vapour treatment chamber and arranged so that vapour condensed therein returns to the boiler, a device for the introduction of yarn into the chamber at a linear velocity V1 and a device for the discharge of the yarn from the chamber at a linear vleocity V2, the velocities V1 and V2 being so chosen that V2 is at least three times V1. As shown in Fig. 1, a liquid 11 in a boiler 1 is boiled by a jacket 2 for heating the boiler by means of a fluid or electricity. A yarn 10 is introduced by a feed roll 7 downwards into a vapour treatment chamber 3 mounted above the boiler 1 and having a heat-insulating jacket 4. A condenser 5 surrounded by a cooling jacket 6 is situated above the chamber 3. The yarn 10 passes under a roller 8 carried by a rod 12 so as to be situated in the chamber 3, and then upwards out of the chamber to a draw roll 10, the ratio of the peripheral velocities V1 and V2 of the feed and draw rolls respectively being such that V2 is at least three times V1. The rod 12 may be arranged to be vertically movable in order that the yarn may be initially engaged around the roller 8 outside the vapour treatment chamber. As shown in Fig. 2, the vapour treatment chamber 15 communicates with the boiler 13 through a pipe 17, and the liquid condensed in the condenser 18 is collected in an annular gutter 20 and conducted by a pipe 21 to a purifying device 22 before it is returned to the boiler 13 through a pipe 23. The apparatus is particularly suitable for the drafting of polyacrylonitrile yarns in saturated steam.