Patent GB-633108-A (GB)
Title: Improvements in process and apparatus for the production of synthetic thread
IPC: D01D10/04
Filed: 1947-04-14
Abstract: <PICT:0633108/IV (a)/1> <PICT:0633108/IV (a)/2> <PICT:0633108/IV (a)/3> <PICT:0633108/IV (a)/4> Artificial threads, freshly formed from a spinning solution, are drawn along in a substantially horizontal path into and through one or more baths of treating liquid close to the upper surface of the liquid in such manner that the speed of the travelling threads and the spacing of the threads cause a circulation of the liquid. The process may be applied to the production of artificial threads by the cuprammonium or the viscose process or to the production of cellulose ester, cellulose ether, casein, or zein artificial threads.  The treating liquids may be contained in a shallow trough or troughs divided into sections and they may travel in counter-current to the threads.  The tension in the threads is controlled by the relative speed of extrusion and the speed of collection.  The threads run substantially horizontally between the extrusion station and the place of collection and are not supported other than by the tension to which they are subjected, and the buoyancy of the liquid.  The shallow trough may be slightly tilted to assist counter-flow of the liquid and it may be separated into sections by dams having staggered openings to allow circuitous flow of liquid along the trough bottom.  The supply of liquid is such that it also flows over the top edges of the dams beyond the threads, and may also be such that there is maintained a wall of liquid extending along the upper edge of each of the dams in the path of the threads so that contamination of a body of liquid by liquid adhering to the travelling threads is minimized. The movement and spacing of the threads are such that in each section of the trough between the dams a surface current of liquid in the direction of the threads is set up so that the liquid circulates in each section.  Cuprammonium cellulose threads may pass continuously with production through acid-washing baths, water-washing baths, sizing apparatus, and drying apparatus and finally to a winding machine.  As shown in Fig. 3b, threads taken from a large number of stretch-spinning funnels, diverted round guide-rods, and spaced by means of combs, are passed through guide 26 and comb 28.  From this comb the threads pass through comb 31 and over support 30 to another support 29 which is provided with several blades and which may be rotated when required to present a new blade to support the threads.  The blade of support 29 is slightly higher than the base of comb teeth 28.  Liquid draining from the threads is collected by trough 24.  The threads pass on through trough 32 (Fig. 3c).  Guides 34, 35 cause the threads to engage closely a film of liquid on the upper surface of dam 36.  A series of spaced dams 37 are provided.  Depressors 39 and combs 40 are also placed at intervals along the trough.  Acid introduced through inlet 38 (Fig. 3d) flows in the opposite direction to the threads owing to the slight inclination of the trough.  Water is introduced through pipe 42 (Fig. 3e).  The threads pass from the trough, without deviating from the general straight line of travel, over a drip catch plate 48, through comb 49, and then over roller 50 which applies size or other finishing liquid from trough 51.  The threads then pass on in the same straight line of travel through two drying chambers.  The dried threads pass through a comb and thence to winding devices.  The arrangement is such that the threads are drawn from the place of formation, through all the treating and drying apparatus, to the place of collection solely by the pull of the collecting devices.  For convenience in starting the operation, temporary collecting bobbins and portable separators or combs may be provided.  In the cuprammonium process, the precipitation of copper hydroxide in the spinning funnels may be minimized by the addition of sorbitol to the coagulating bath.  The roller 50 may apply a solution of sulphonated oil and soap containing a fugitive dyestuff for identification purposes.  Specifications 337,608, [Class 2 (ii)], and 365,502 are referred to.