GB392218A - Improvements in or relating to the manufacture of artificial filaments or the like - Google Patents

Abstract

<PICT:0392218/IV/1> <PICT:0392218/IV/2> <PICT:0392218/IV/3> <PICT:0392218/IV/4> <PICT:0392218/IV/5> A modification of the apparatus described in the parent Specification comprises a spinning cell with spinning jet, means for passing a current of evaporative medium through the cell, and means for introducing additional evaporative medium in the neighbourhood of the jet, said means comprising a conduit, arranged within the cell, extending over a length covering the extremes of the positions at which evaporative medium is to be injected, and provided with a series of apertures through any of which air may be injected as desired. Such of the apertures as are not required for a particular spinning operation may be closed by apertured registers or caps. The apertures may take the form of slots which direct the air over the whole width of the space occupied by the bundle of filaments issuing from the jet. Another modification comprises apparatus in which the conduit for the additional air is of such cross section and of such material as to facilitate transfer of heat from the air in the cell to that passing through the conduit. As shown in Fig. 1, filaments 14 are extruded from a jet 13 in a spinning cell 10 and pass from the cell over a wick 17 which moistens them with lubricant or other liquid, over a feed roller 18 and then to a cap spinning device 20. Air enters the cell at 23 and is withdrawn at 24. Additional air enters the cell through the conduit 30 and apertures 31, 32. The conduit is provided with pressure header 33 and a control device 35. As shown the apertures 31 are closed by caps, while the aperture 32 is open. As shown in Fig. 2, the cell contains two spinning jets 13 and two conduits 30 disposed in the corners of the cell. The air injected through orifices 31 crosses the cell beneath the jet and leaves by the draw-off pipe 24. A door in the casing of the cell gives access to the jets and to the conduits 30. If desired control of the apertures 31 may be arranged to be effected from outside the cell. The conduit 30 is of flattened cross section in order to present a large surface to the warm air in the cell 10. The temperature of the air injected is thus raised approximately to that of the cell. To this end, the conduit is made of material of high heat conductivity, e.g. copper, the walls being as thin as practicable; it may be corrugated or be finned or grilled, or be annular in form, and it p may be arranged to have a long path within the cell. If desired, the additional air may be heated by surrounding the conduit outside the cell with a heating jacket. As shown in Fig. 4, a device for controlling the supply of additional air comprises a chamber 45 closed by a cap 46, which communicates with the header 33 through a pipe 34, and with the conduit 30 through a passage 49, the rate of flow of air being controlled by a screwed plug 50 having a precisely drilled orifice 51. Variation of flow is obtained by substituting the plug 50 by another having a bore of different size. In the construction shown in Fig. 5, an adjustable needle valve 53 working against a seating 54 is used instead of the plug 50. The apparatus may be used with all forms of dry spinning apparatus whether constructed for upward or downward spinning and whether the evaporative medium travels in co-current or counter-current with respect to the filaments. As shown in Fig. 7, the main current of air which enters at the bottom of the cell is removed through the pipe 70 above the jets. An additional draw-off pipe 72 is provided opposite to the nozzles 31, 32 in order to obtain a current of air across the cell just below the face of the spinning jet 13.