Patent GB-729446-A (GB)
Title: Improvements relating to the continuous manufacture of rayon yarns
IPC: D01D10/04
Filed: 1952-02-25
Abstract: <PICT:0729446/IV (a)/1> Regenerated cellulose yarns are made continuously by extruding viscose solution from adjacent nozzles into a coagulating bath to produce yarns which are led as groups composed of adjacent spiral circuits through a horizontal roller bed composed of successive pairs of vertically superposed smooth top and bottom rollers, each pair of rollers being located above one of a series of successive treating baths; the lower roller of each pair is adapted to receive liquid from the bath and each pair of rollers extends substantially the entire width of the bath, the roller axes of each pair being disposed <PICT:0729446/IV (a)/2> <PICT:0729446/IV (a)/3> in the same vertical plane and one of the said rollers being tilted relatively to the other roller so that the distance between the axes of the said rollers increases in the advance direction of the yarns along the rollers from one end to the other end of the roller.  The yarns are subjected during their travel past the rollers to successive regenerating, washing, treating and finishing steps.  As shown, the spinning equipment comprises a long trough 1 divided by partitions 2 into compartments a, b, c, d, e ... according to the number of processing steps.  Vertically spaced non-parallel roller pairs 3, 31, 311 ... and 4, 41, 411 ... are co-ordinated to these compartments, the axis of each upper roller being tilted in the vertical plane relative to the lower (horizontal) roller.  A doctor and a trough are provided beneath each upper roller to remove and collect surplus treating liquid.  The viscose is extruded through the spinnerets 20 into the coagulation bath a and led to the upper roller 4 of the first roller pair, the lower roller 3 of which is partly immersed in the regnerating bath b.  Compartment c may also be a regenerating bath, in which case the treating liquid may operate on the counter current principle through inlet tube 33 and outlet pipe 34, the partition between b and c having a connecting passage 331. If desired, the roller pair receiving the incompletely regenerated yarns may be rotated at a greater speed than the preceding roller pair, thus stretching the yarn.  The following roller pair may then effect a shrinking by a speed reduction.  In order to counteract the slight stretch due to the travel up the tilted roller, alternate pairs may be tilted in the opposite direction (see Fig. 4).  After passage over the roller pairs, whereby the yarns are successively regenerated, washed, desulphurized, washed and impregnated or finished as desired, the yarns are dried over drums 24, crimped by rollers 25 and collected.  Guide rollers may be used between particular baths to assist in conducting the yarns.  The yarns may be impregnated with rubber latex as part of the treatment, in which case treatment with a cationic wetting agent and/or an organic (aromatic) acid prior to impregnation may be carried out.  If desired the lower roller may be in contact with a smaller roller 35 (Fig. 5) which is kept in contact with the bath liquid and applies it to the lower roller 3.  The treating liquids may be sprayed on to the upper rollers if desired.