GB1371340A - Process and apparatus for texturising yarn - Google Patents

Abstract

1371340 Crimping yarns PLATT INTERNATIONAL Ltd 29 Dec 1971 [31 Dec 1970] 62060/70 Heading DIF A running thermoplastic continuous filament yarn is bulked by subjecting it successively to drawing, softening under a predetermined first tension by passage through a heating zone, imparting false-twist, cooling to set the twist and thereby produce crimp therein, and heating in one or two stages under similar or different predetermined constant second tension(s) in a reheating zone to modify the crimp. The crimped yarn may be overfed to the reheating zone by an amount e.g. 5-25%, which is slightly overcompensated by contraction of the yarn therewithin resulting in a melt constant tension e.g. less than 1 grm/denier. Cooling of crimped yarn and/or winding into a package may be effected under predetermined, perhaps increased tension(s). In the operation of the split-frame, draw-texturising machine shown, undrawn polyethylene terephthalate yarn 2 unwound from a cheese 4 by feed roller assembly 6 and stretched by draw roll assembly 8 proceeds to, around and in contact with, a heater 10 thence through a cooling zone 12, a pair of (false-)twisting bushes 14, 15, and feed rolls 16 to a second heater 20, through a cooling zone 32 and feed rolls 18 (permitting crimped yarn 2 to contract by as much as the intended 15% overfeed will allow) and the modifiedcrimp yarn 2 is packaged by a cross-winding head 36. The (relative) speeds of feed rolls are such as to produce the desired tension conditions. The heater 20 comprises a block 21 providing two electrically heated faces 22 and 24 in contact with which the yarn, is passed in a number of wraps by driven rollers 26, 28. In a modification, heater 20 is replaced by a heater providing two slightly convex contact surfaces insulated from each other and over which yarn may be underfed or overfed to effect upward then downward travel and be heated or heated and then cooled.