GB831434A - Improvements relating to the production of artificial slub yarns - Google Patents

Abstract

<PICT:0831434/IV (a)/1> Artificial multifilament yarns of one colour having slubs of a different colour are made by extruding through a spinning jet a first fibre-forming liquid at uniform pressure having the colour of the yarn, and intermittently interrupting the flow of the first liquid to the jet face by injecting intermittently, at a pressure greater than that at which the first liquid is supplied to the spinning jet, a second fibre-forming liquid having the colour of the slubs at a point immediately behind the jet face, but spaced sufficiently from the jet face to allow the first fibre-forming liquid to regain access immediately to the whole of the jet face and to resume extrusion at the end of a slub formed from the second fibre-forming liquid which, being extruded at a greater pressure, has a higher volumetric rate of extrusion than that of the first fibre-forming liquid. Preferably, immediately after the cessation of the supply of the second fibre-forming liquid to a point immediately behind the jet face, the pump controlling the liquid sucks back a small quantity of the liquid to provide a sharp change of colour and denier at the tail end of the slub. As shown, a conical spinning jet 1 is secured to a rounder end 2 by a screwed coupling 3, a seal being formed by the rubber ring 4. A nozzle 5 is supported centrally close behind the face 6 of the jet 1 by radial centring members 7. The nozzle is connected by a pipe 8 provided with a strainer to an injector-type pump (described in Specification 812,022) which delivers coloured viscose in sharply-defined pulses at a pressure higher than that of the clear uncoloured viscose supplied at a uniform rate through the rounder end 2 by a gear-type metering pump. The injector type pump may be actuated by a cam or by a pneumatic piston in a cylinder to which the supply of air is controlled by an electromagnetically-operated valve. The pipe 8 is made rigid and as short as possible, to reduce its elasticity to a minimum and thus obtain sharp changes in colour at the ends of the slubs. The spring-loaded delivery valve in the injector pump may itself be shaped as a plunger working in the delivery valve chamber, so that it sucks back slightly as the valve closes, thus absorbing any "tailing" effect due to the unavoidable small elasticity of the pipe 8. The jet 1 is immersed in a regenerating bath and the threads are taken over a guide positioned above the surface of the bath and then underneath a guide positioned beyond it in the bath to a godet or other take-up device. The first guide has the effect, particularly necessary at spinning speeds above 50 metres per minute, of preventing the slubs in the various individual filaments from moving longitudinally and thus becoming displaced. French Specifications 766,852, 803,144 and German Specification 741,595 also are referred to.