Patent GB-822727-A (GB)
Title: Spinneret head for synthetic fibre spinning
IPC: D01D4/00
Filed: 1956-05-07
Abstract: <PICT:0822727/IV (a)/1> <PICT:0822727/IV (a)/2> <PICT:0822727/IV (a)/3> A spinneret head comprises an elongated hollow body member, a cap closing one end of the member, a filter element in the form of a hollow generally cylindrical body having a greater length than diameter and having a permeable longitudinal wall, the element being coaxially detachably mounted within the body so as to form an annular passageway between the walls of the body and the element, conduit means for conducting spinning solution to the passageway, the general direction of flow of the solution being radially from to the interior of the element, a spinneret holder detachably mounted at the end of the body member opposite the cap in such a manner that the axis of the spinneret face is at an angle to the longitudinal axis of the filter element, and conduit means in the spinneret holder for conducting the spinning solution directly from the interior of the filter element to the spinneret. As shown in Fig. 1, a spinneret assembly 10 specially adapted for immersion in a cold liquid coagulating bath includes a spinneret 16 and a spinneret head 18 (Fig. 2), comprising an elongated body member 20 and a spinneret holder 22 detachably mounted thereon at an angle of 90 degrees.  The body member 20 is provided at one end with a removable closure cap 24.  A cylindrical filter cartridge 26 is detachably mounted in the body member 20 and comprises a filter core 28 the exterior of which is provided with screw threads 30 and holes 32 for the passage of spinning solution from the exterior to the interior of the core.  The filtering area of the core 28 is enveloped by a 30X30 mesh wire cloth screen 34 which forms a support for the porous filter medium 36 which may consist of two or more wraps of nylon cloth covered by a sheath of Vinyon N fabric shrunken over the other layers by immersion in hot water.  The filter medium 36 is held in place on the core 28 by cords 42 tied at the upper and lower annular grooves 38 and 42 on the core 28.  A cylindrical hollow metal insert 44 fits within the cartridge 26 spaced a small distance from the inner surface of the core 28 thereby forming a narrow passageway 46 of annular cross section for the downward flow of filtered spinning solution to a passageway 56 in the spinneret holder 22.  The object of the heat insert 44 is to minimize heat loss of the hot filtered spinning solution to the cold aqueous coagulating bath in which the spinneret assembly is immersed by reducing to a minimum the period of residence of the spinning solution in the filter cartridge 26. From the passageway 46 the filtered spinning solution flows through the passageway 56 between the conical extension 48 welded to the bottom of the insert 44 at 50 and a conical recess 54 in the main body portion 52 of the spinneret holder 22.  The passageway 56 leads into the conduit 58 which is drilled in the main body portion 52 and which widens as shown at 60 to the diameter of the spinneret 16 detachably clamped thereto.  The externally-threaded upper end of the hollow insert 44 is screwed into the internally-threaded member 62 to form the union 64 which is rendered liquid tight by means of a gasket 154 of neoprene or compressed asbestos nipped between the member 62 and a shoulder 152 welded to the insert 44.  The threaded member 62 has a side wall which extends downwardly to form the inner casing 66 which with the wall 68 of the filter cartridge 26 forms the passageway 70 for conducting spinning solution to the filter cartridge.  The inner casing 66 is surrounded by an outer casing 72 comprising an inner layer 74 of a porous thermal insulating material such as foamed polyester resin and an impervious outer layer 76 of strong and rigid thermal insulating material such as nylon.  The elongated body member 20 is provided at its lower end with a resilient gasket 78 and a reinforcing ring 80 of nylon.  The filter cartridge 26 is provided at its upper and lower ends with O-rings 82 and 84 for sealing purposes. The spinning solution is introduced into the body member 20 through the externally-threaded conduit 88 (Fig. 2), screwed into the internally threaded member 86 welded to the inner casing 66 and through an opening 156 in this casing.  The nylon cap 24 closing the top of the elongated body member 20 is attached to the member 62 by means of screws 90 (Fig. 2), and is provided with a screwed plug 92 having small openings which communicate with the passageway 70 by means of a conduit 94.  The main body portion 52 of the spinneret holder is formed of a strong rigid material which is a poor heat conductor, e.g. nylon and is provided with recesses 100 and 102 (Fig. 2), into which fit the pins 104 and 106 for aligning the body member 20 with the portion 52 of the spinneret holder.  The body portion is provided with a recess 108 closed by a nylon plug 110 provided with an O ring 124 for excluding liquid coagulant from the recess.  The elongated body member 20 and the spinneret holder 22 are rigidly held together by means of a stainless steel rod 114 terminating in a threaded portion 116 upon which is screwed a nut 118 bearing against the washer 120.  Leakage of spinning solution is prevented by the O-ring 122 located in a circumferential groove on the rod 114.  The spinneret 16 is held in osition in its holder 22 by means of a stainless steel detachable ring 126, a liquid-tight joint being obtained by means of resilient lining 144, bonded to the ring, and a resilient ring 148 and nylon gasket 150 on each side of the lip 146 of the spinneret.  The ring 126 is held tightly in position by means of a yoke 132 (Fig. 3) having arms 134 slotted at 138 and 140.  Into these fit the bosses 128 and 130 on the ring 126 by bringing the yoke into its normal operating position and tightening the screw 142 (Fig. 1).  The screw 142 has a guide extension 158 which fits into a corresponding recess in the metal plate 160 embedded in the rear end of the nylon main body portion 52.  The latter is cut off at 162 so that the yoke 132 clears it when it is swung downwardly into a non-operating position to enable the spinneret to be detached.  The device is particularly adapted for the spinning of hot spinning solutions such as solutions of acrylonitrile polymers into low-temperature coagulating baths, cooling of the hot solution in the spinneret head by the cold bath liquid being minimized.