GB687212A - Improvements in or relating to the manufacture of artificial yarn - Google Patents

Abstract

A device for stretching a bundle of acid-wet artificial cellulose filaments received from a spinneret comprises a pair of sets of spaced parallel rods, those of one set being interleaved with those of the other set, a fixed member carrying one of the sets and a pivoted member carrying the other set, with the rods of the two sets displaced to provide a zig-zag path of increasing sinuosity for the filaments passing thereover; the pivoted member is capable of movement about an axis parallel to the rods, whereby the overlap of the zig-zag path may be varied, and means are provided for urging the pivoted set of rods into a position of increased overlap with respect to the fixed set of rods. Preferably each set of rods is carried by a bar, the bars are pivoted together, and one bar is weighted to urge it towards the other bar. The device may be used in the production of rayon threads from viscose with coagulating baths of concentrated sulphuric acid. Stretching of 300-400 per cent may be effected. As shown, filaments extruded from spinneret 1 form a yarn 3 as they travel through an acid coagulating bath towards roller 4, which is mounted loosely on spindle 5 outside the bath liquid. The liquid may splash on to spindle 5 so as to <PICT:0687212/IV (a)/1> <PICT:0687212/IV (a)/2> act as a lubricant for roller 4. The yarn passes to freely-mounted roller 6 and thence to a stretching device 8. This device comprises two sets of parallel rods of glass, stainless steel, sintered alumina or other acid-resistant material, one set a, b, c, being secured to bar 9 and the other set, a1, b1, c1, being secured to bar 10. Bar 9 is pivoted to bar 10 by pin 16, and its free end carries a rod 11 along which a weight 12 may be moved to vary the downward force on the upper set of rods, a, b, c. After threading the yarn through the device, the bar 9 is lowered to a position such that the yarn follows a sinuous path in which the extent of the zig-zag increases from the feeding end to the delivery end. The position of the rods and the path of the yarn during the stretching operation are indicated in broken lines in Fig. 2. The yarn tends to arrange itself in the form of a flat band or ribbon as it passes through the stretching device. The yarn passes from the stretching device 8 to a roller 13. Further stretching may take place between rollers 13 and 15, and between roller 15 and a delivery cylinder. Rollers 6 and 15 have radial passages extending from their peripheries to the spindle 7 so that coagulating liquid passes to spindle 7 and acts as a lubricant therefor. Roller 13 or its spindle is helically grooved to draw up bath solution between spindle and roller for lubrication. Specifications 287,553, 318,258, [both in Class 2 (ii)], 396,901, 397,509, 650,896 and 652,645 are referred to.