| 摘要 |
304,754. Wolff & Co., and Weingand, R. Jan. 26, 1928, [Convention date]. Apparatus for making films.-Seamless flexible tubes of any desired length are prepared from cellulose solutions particularly viscose by allowing the cellulose solution to issue solely by its own weight and without the aid of extraneously applied pressure from an annular nozzle, directly into a. coagulating bath, whilst a precipitant liquid is introduced at the same time inside the nozzle and the tubular layer issuing therefrom. The spent portion of the precipitant inside the flexible tube is continuously removed by a syphon tube and suction device, the level of liquid inside the tube being preferably maintained at the same level as or somewhat higher than that of the external coagulating bath. In the form of apparatus shown in the Figure, the cellulose solution, such as viscose, flows solely by its own weight direct from the annular nozzle 1 into the precipitating bath 2 as a cylindrical layer 3. The tube 4, which serves to admit the precipitated liquid into the interior of the flexible tube 3 in course of formation, is provided with a regulating valve 5 and projecting through the nozzle 1, which may dip slightly into the precipitation bath. The spent portion of the precipitant liquid is continuously carried off through the syphon 6, which dips at one end only a short distance below the surface of the interior precipitant liquid and at the other end dips into the precipitation bath 2, from which the spent precipitant can be run off through the overflow 7. The supply of the precipitant liquid to the interior of the tube can be regulated by the valve 5, so that its renewal always keeps pace with the consumption, the rate of which depends upon the character of the cellulose solution, the working speed and the dimensions of the flexible tube. Uniformity of the flexible tube is maintained by the equality of pressure continuously maintained between the exterior and interior precipitant liquid by the syphon 6 and the tendency of the tube to contract may be counteracted by a positive pressure generated, for example, by adjusting the interior precipitant to a higher level than that of the exterior precipitation bath. A heavy longitudinal tension can be applied to the tube during formation in order to control the thickness of the tube and the whole process can be carried out in a continuous manner up to the drying stage by transferring the tube by means of rollers 8 and 9 from the bath 2 for further treatment in the usual washing, bleaching, desulphurizing, dyeing and plasticizing baths. |
