GB697967A - Improvements in or relating to wet-spinning cells - Google Patents

Abstract

A wet-spinning cell for the production of artificial filaments comprises a spinning chamber containing one or more fixed spinning jets, a vertical setting tube up which the extruded filaments and the coagulating liquid travel and whose internal wall is smooth, and at the upper end of the setting tube a collector head for the coagulating liquid having a run-off for liquid leading therefrom, the said collector head being completely or nearly completely closed against the outside atmosphere so as to provide a complete or nearly complete seal against the escape of vapour from the spinning cell into the atmosphere. The collector head may be a <PICT:0697967/IV (a)/1> <PICT:0697967/IV (a)/2> separate device which can be fixed to the upper end of the setting tube to make a liquid-tight joint therewith. The spinning chamber and setting tube are preferably separate structures which can be readily brought together to form a liquid-tight joint. As shown in Fig. 1, spinning chamber 11 is provided with spinning nozzle 13 and inlets 12 for coagulating liquid. A perforated disc 14 reduces turbulence. Setting tube 16 with conical portion 15 is attached to the spinning chamber 11, e.g. by means of a screw-thread of high pitch and with abutting surfaces bedding on rubber washers. The collector head comprises a lower section 18 and an upper section 19. Section 18 comprises tube 23 and outer wall 24 forming an annular passage open at the top and having a liquid run-off 25 in its base. Perforated plates 26, 28 hold a filtering material between them. Upper section 19 has a flange 20 which fits closely into the open end of section 18. It carries an annular projection 29, in which are scallops 30, for spacing the flange 20 above plate 28. The upper end of section 19 may be closed by a hinged lid containing a slit 22 for passage of the yarn from the cell. The filaments may be brought together to form a yarn at a level below the top of tube 23, e.g. by means of an adjustable skew-pulley, situated above the cell, which imparts a false twist. As shown in Fig. 2, the setting tube 16 carries a collector head 40 which comprises a body 41 and a cap 42. A liquid run-off 43 and a drain 44 are provided. A lateral tube 45 opens into the base of the collector head and connects with a removable extension tube 45A provided with a tangential feed-tube 47 for the supply of a treating liquid. Tube 45A extends above the level of the run-off 43. The lower end of tube 45 has a spigot 46 with an orifice which allows the desired rate of flow of liquid down and out of the tube. An adjustable free-running pulley 48 guides the yarn into tube 45A. This pulley may be mounted in skew-fashion so as to impart a false twist to the yarn. If it is desired to prolong the treatment of the yarn with coagulating liquid, the tube 45A may be removed and the pulley 48 adjusted to direct the yarn into tube 45. The apparatus may be used for the production of cellulose acetate yarn by a wet-spinning method in which the spinning solution is extruded into aqueous acetone or into an aqueous solution of diethylene glycol diacetate. Specifications 654,900 and 695,559 are referred to.