Improvements in or relating to means for entrapping gases from machines for manufacturing and treating viscose products

摘要

Apparatus for continuously forming and treating filaments, yarns, films, bands, or other articles or products from viscose, is provided with means for entrapping gases comprising a hood adapted to cover part or all of the forming and treating devices, a liquid seal to receive the hood, means for raising and lowering the hood, a fixed ventilating shaft passing through a duct formed in the hood, and means for drawing gases into the ventilating shaft. If desired a further, separate ventilating shaft may be provided, and the first ventilating shaft may be adapted to close automatically against communication with the hood when the latter is lowered and to open into communication therewith when the hood is raised. As shown in Fig. 1, viscose is discharged into vat 1 from a hopper and is coagulated to form a film. The film is passed to a second vat 2 containing an acid bath, then into vat 3, and subsequent vats, containing a heated water bath, e.g. at 85-95 DEG C. Rollers 4, 5 are provided so that the film travels in a sinuous path. A common trough 6 formed round the upper edge of the vats, contains water or other liquid. A hood 7 is supported by a hydraulic jack 8 so as to overlie vats 2 and 3. When hood 7 is lowered its free edge enters trough 6 and a liquid seal is formed. The hood is provided with a duct 9 which receives a ventilating shaft 10 with nozzles 11. Valve 12 regulates the flow of gases and vapours through the shaft. As shown in Fig. 3, p suction may be applied to the vats both when the hood is open and when it is closed, the suction being greater when the hood is open. Vat 14 is normally covered by hood 13 which dips into liquid seal 15. A fixed ventilating shaft 16 is provided. A fixed casing 17 is supported by cross-bars 18 and there is an additional shaft 19. Casing 17 carries trough 20 which forms a liquid seal and into which flange 21 may enter when hood 13 is lowered. When hood 13 is raised, after the suction in shaft 19 has been stopped, the seal at 20 is broken so that gases in the vat are drawn off through shaft 16. Before raising the hood, its inner surface may be swept with an inert gas, e.g. nitrogen, to prevent air from forming explosive mixtures with gases rich in carbon disulphide.