Patent GB-756819-A (GB)
Title: Production and treatment of artificial filaments
IPC: D01D10/04
Filed: 1954-10-07
Abstract: Artificial filaments are extruded into a setting tube through which coagulating liquid flows, the filaments being drawn out of the setting tube and passed through one or more treating tubes coiled helically round the setting tube and through which treating fluids flow.  If there are several treating tubes they are preferably coiled in inter-laminated helices.  The treating fluids are introduced into their respective treating tubes by injectors, which also feed in the filaments.  The filaments are stretched during setting by causing the coagulating liquid to flow through the setting tube at a faster rate than the filaments, and also after setting by driving the draw-off roller at a high speed. When producing filaments from a cellulose acetate solution in acetone and a coagulant of an aqueous solution of acetone, treatment carried out in the treating tubes may include a washing to remove coagulant, a saponification with sodium hydroxide solution and a further washing treatment.  As shown in Fig. 1, filaments spun from the jet 13 are drawn up the setting tube 11 by driven roller 19 at sufficient speed to impart stretch, whilst coagulating liquid is passed in at 12 and drained off at 14 sufficiently fast to <PICT:0756819/IV(a)/1> <PICT:0756819/IV(a)/2> <PICT:0756819/IV(a)/3> stretch the filaments whilst they are still setting.  The setting tube 11 can be raised, giving access to the jets, by lifting lever 73.  The filaments take half a turn round a groove in driven roller 19 and are then led down into funnel 27 into which they are drawn by injector 29, which is fed with treating liquid from supply line 24 and which passes the filaments and treating liquid through helix 38, see also side elevation, Fig. 3. At the bottom end of helix 38, the treating liquid is discharged into trough 41 and the filaments are led over pulley 42, up to roller 19 round which they pass for half a turn, and down into a second injector fed with a second treating liquid from supply line 47, the filaments and treating liquid passing through a second helix 48 inter-laminated with the first.  This may be repeated with further treating liquids if desired.  The filaments are then led over driven roller 19 and drip pan 53 to drying chamber 56 and winding device 63. As shown in Fig. 3, driven roller 19 is grooved and each passage of the filaments over the roller is made in a separate groove whereby contamination of the different treating liquids is avoided, contamination being assisted by the provision of an arcuate shield 68 in each groove (only one is shown) which immediately surrounds the filaments in their groove, each such shield having its own trough 69 for drainage.  Fig. 4 shows the injector 29 which feeds liquid and filaments into the helical treating tube.  Treating liquid enters at 23 and on its way through the restriction 34 to treating tube 37 creates a zone of low pressure at 33 into which the end of the filament-guiding tube 28 projects, whereby filaments placed in the funnel 27 are sucked into the injector and carried through the helical treating tube by the liquid flow.