Patent GB-837300-A (GB)
Title: Improvements in method and apparatus for the production of artificial slub yarns
Inventor: HOFMANN HUGO
IPC: D01D5/20
Filed: 1956-09-20
Abstract: <PICT:0837300/IV (a)/1> In the funnel-spinning of artificial yarns having slubs of randomly variant denier in which the filaments are not completely coagulated in the funnel and are therefore still in a gel or tacky condition when they are discharged from the bottom of the funnel, an increased flow of coagulating liquid is delivered to the funnel periodically at predetermined intervals of time, the increased flow being in the nature of surges, thereby disrupting the take-up of the filaments issuing from the funnel, and the filaments are delivered in piled relation beneath the funnel, the pile-up of filaments being temporary and thereby effecting a slubbing action at substantially regular intervals along the filament bundles prior to the take-up thereof.  The spinning solution may be of any type appropriate for funnel spinning, e.g. viscose or cuprammonium cellulose spinning solutions.  As shown in Fig. 1, a supply mainifold 8 delivers a cuprammonium spinning solution in the usual manner to a spinneret disposed in the spinning head 7 of a conventional spinning funnel 5.  Coagulating liquid is also delivered to the funnel through lead-in tube 12 in the usual manner.  The extruded filaments 6 proceed down the funnel 5 along with the coagulating liquid and, during the period of spinning yarn of uniform denier, the flow of coagulating liquid is normal and the filaments pass in a normal path around guide 14 to a take-up reel.  The normal flow of coagulating liquid is adjusted by means of the manually-operated valve 20.  A by-pass line 22 provided with manually-operated valves 24, 27 is connected around the valve 20.  During the part of the repeated cycle of spinning in which yarn of uniform normal denier is being produced, the flow of coagulating liquid through the by-pass line 22 is prevented by the normally closed spring-loaded poppet valve 26.  This valve is opened at predetermined regular intervals for a predetermined period by means of a cam 30 which engages the stem 28 of the poppet valve and is driven via a reducing gear 34 by the variable speed motor 32.  The shape of the cam and its direction of rotation are such as to lift valve 26 off its seat quickly to give the resulting flow increase of the coagulating liquid a surge characteristic, and to allow the valve to return to its seat slowly to avoid a waterhammer effect.  In a modification the poppet valve is actuated by an air-operated diaphragm valve, the flow of air to which is controlled by a solenoid valve operated by a conventional electrical repeat cycle timer.  When an increased flow or surge of coagulating liquid is periodically delivered to the spinning funnel 5 by the periodic automatic opening of the valve 26 or its diaphragm valve equivalent, the normal take-up of the filaments 6 is interrupted, and they are temporarily deposited on a flat plate 16, which may be slightly inclined, in an incompletely coagulated condition in the form of small loops and snarls which adhere together to form a slub in the yarn.  When the normal flow of coagulating liquid is resumed, the filaments are taken up again in the manner of normal spinning and the therefore of normal denier.  In a modification, a flat-bottomed circular dished receptacle is provided instead of the plate 16, to produce smaller slubs.  Specification 460,626 and U.S.A.  Specification 2,125,230 are referred to.