METHOD AND APPARATUS FOR HEAT-TREATING AND TEXTURING TRAVELLING THERMOPLASTIC YARNS

1298631 Texturizing apparatus DEUTSCHE AKADEMIE DER WISSENSCHAFTEN ZU BERLIN 9 Jan 1970 1098/70 Heading B5B In threading-up at the start of the heat-treatment and texturizing of travelling thermosplastic yarns, the yarn is guided on to a first heating device which is flat and is maintained at a temperature below the melting point of the yarn, and, after the yarn has reached its full speed in the apparatus, the yarn is transferred, transversely to the initial path of travel of the yarn, on to a second heating device maintained at a temperature which is above the melting point of the yarn, whereby the temperature of the yarn is raised to a level at which it becomes heat set. As shown in the apparatus of Figs. 1, 2 and 3 (only Fig. 3 is shown) Fig. 3, which comprises means for continuously advancing a yarn and two heating devices along which the yarn may alternately be passed, a first flat heating device 2 is arranged in the form of a heating element arranged next to the second heating device 1, firmly connected to the latter and heatable thereby by thermal conduction. In the apparatus of Figs. 4, 5 and 6, (not shown), heating device (2) is a heating element spatially separate from the second heating device (1) and provided with separate heating means, and in the apparatus of Figs. 7, 8 and 9 (not shown), heating device (2) is a metal sheet arranged at a variable distance above the second heating device by means of distance elements. In any of these forms of apparatus, yarn guides 4 pivotable about bearings 3 are provided at the entry to and exit from the second heating device 1 for transferring the yarn 15 from the first heating device 2 to the second heating device 1. In the apparatus of Figs. 10 and 11, the first heating device is a flexible sheet steel band 9 tensioned over the second heating device 1 by springs 8 and resting upon rollers 10. Band 9 is heated by thermal radiation and convection from heating device 1, and its temperature can be varied by varying the distance between band 9 and heating device 1 by the operation of eccentrics 11. Yarn guides 12 are fixedly mounted on bearings at the entry to and exit from the heating device 1.