| 摘要 |
<PICT:0822865/IV (a)/1> A rotary screen suitable for the separation of a precipitated cellulose ester from a slurry thereof in a continuous manner comprises a central core capable of being rotated, a helical vane carried by the core, a screen secured to the outer edge of the helical vane and forming the circumference of a drum, and feed means adapted to lead a cellulose ester slurry into one end of the drum. As shown in the drawing, the separator comprises a core 1 mounted for rotation in bearings 2 and attached to a driving shaft 3. A helical vane 4 is rigidly fixed at its inner edge to the core 1, and extends over the greater part of the length of the core. Four equally spaced longitudinal frame members 5 extend parallel to the core over the whole length of the vane 4 and are fixed to the outer edge; these members in turn carry ribs 6 at intervals along the length of the vane, the outer edges of the vane 4, the members 5 and the ribs 6 being all flush with one another. The screen element of the separator comprises a wire cloth 7 held directly against the outer edges of the vane 4 and the members 5 and 6, and a perforated metal sheet 8 outside the wire cloth and serving to support it. The wire cloth 7 and perforated metal sheet 8 are made in panels for easy fixing and removing and are held against the supporting edges by longitudinal clamping members 9 which extend along the longitudinal frame members 5 and are fastened to them by set screws at intervals along their length. A partial closure 10 extends inwardly from the input end of the screen element and is fastened to the ends of the longitudinal frame members 5. An inclined feed pipe 11 extends into the drum formed by the screen element, passing to one side of the core 1, the inner part of the input end convolution of the helical vane 4 being cut away sufficiently to prevent it fouling the feed pipe when it rotates. Similarly the partial closure 10 extends only so far inwards as will not cause it to foul the feed pipe 11. The whole separator is enclosed within a casing 12 having a floor 13 sloping downwards towards the feed end of the separator and provided with a discharge opening 14 for liquid which has passed through the screen element. A wall 15 extends upwards from the floor 13 of the casing and serves to direct solids discharged from the output end of the rotating screen into the separate discharge opening 16. The rotation of the screen element causes the helical vane to propel the solid material retained on the screen from the feed end to the discharge end of the separator. |
