Patent GB-545250-A (GB)
Title: Improvements in or relating to a method of and apparatus for drying wet thread
IPC: D06B3/04
Filed: 1940-09-02
Abstract: 545,250. Treating textiles with liquids ; artificial filaments &c. ; dyeing &c. apparatus ; drying. INDUSTRIAL RAYON CORPORATION. Sept. 2, 1940, Nos. 13764/40, 13765/40, Convention dates, Sept. 28, 1939 and 13766/40, Convention date, Sept. 29, 1939. [Classes 2 (ii), 15 (i) and 15 (ii)] [Also in Group XIII] A wet thread, filament bundle, band, or like strip material is subjected to a continuous operation of drying by heating, re-wetting, either while the thread is being heated or before it has cooled appreciably, and re-drying, the latter drying being effected under conditions permitting the thread to shrink. The treatment reduces the residual tendency of the thread to shrink and results in a thread of greater uniformity in properties particularly dyeing affinity. The process is particularly applicable to the treatment of freshly formed viscose artificial thread. Treatment may be effected while the thread 'is passing in helical turns round roller-like devices constructed to forward it in axial direction. The various rollers may be arranged one above another but in staggered relation so that the receiving end of one roller is immediately below the delivery end of the preceding roller in the series. As shown in Fig. 2, an artificial thread 1 which has been led from the coagulation bath is subjected to liquid treatments while passing in helical fashion round a series of rollers. As the thread passes round roller 11, washing liquid is supplied to it through pipe 17. While passing round preceding rollers the thread may be treated with additional coagulating liquid, desulphurizing liquids, bleaching liquids, and intermediate washing liquids. The treating liquids may be collected and recirculated. The rollers are inclined so that the treating liquid may travel in countercurrent to the thread. The thread is subjected to drying as it passes round roller 12 which is of metal and heated internally. Just before the dried thread leaves roller 12 it is treated with a small stream of wetting liquid from pipe 29, the amount of liquid being just sufficient to wet the last few turns of thread. The wet thread then passes round roller 13 where the excess liquid is allowed to drip from  the thread, and the moisture content of the thread is rendered uniform. The thread passes to roller 14 where it is dried under uniform conditions. Roller 14 is surrounded by a casing 30 with a hinged lid 32. In order to allow for contraction or elongation of the thread while being subjected to the various treatments, the rollers may be constructed with appropriate diameters and driven at suitable speeds. The drying rollers may be tapered to allow for shrinkage of the thread. The contour of roller 14 may conform closely to the shape of the diminishing helix which the thread tends to develop as it shrinks. The temperature of roller 12 may be higher than that of roller 14 and it may be above the boiling point of the aqueous wetting liquid. In a modified arrangement, the re-wetting liquid is applied to the thread at the receiving end of roller 13. The rollers 12, 14 each comprise two rigid reel-like members of circular cross-section and having a periphery made up of a plurality of bars interleaved with the bars of the other member. The two members rotate about axes displaced from and inclined to each other. As shown in Fig. 5, the member 35 with body portion 40 is mounted concentrically on the hollow shaft 37. The member 36 with supporting member 51 is mounted with its axis inclined and offset from the axis of member 35. The space between the member 40 and the shaft is rendered fluidtight except for the inlet and outlet orifices for the heating fluid which is supplied and removed through the hollow shaft. The eccentric member is driven by the concentric member by means of the toothed members 63 and 64. As shown in Fig. 6, the means for mounting the eccentric member 36a is situated externally of the part 40a, 'and the heating fluid is enabled to contact substantially the whole length of the part 40a. If desired rollers 12 and 14 may be connected in series with the same supply of heating fluid. Specifications 474,973 and 489,781 are referred to.