GB1444376A - Method and apparatus for screening paper fibre stock - Google Patents

Abstract

1444376 Filter apparatus BLACK CLAWSON CO 12 Sept 1973 [12 Sept 1972 (2)] 42911/73 Heading B1D Apparatus for screening paper fibre stock comprises a housing 10 divided by a cylindrical screen 15 into an inner supply chamber 16 and an outer filtered-liquid chamber 17 and containing a rotor 30 carrying vanes 35 adjustably mounted adjacent the inner wall of the screen. The vanes are separated from the screen by a gap of # to ¢" and are rotated at a speed of 3000-12000 f.p.m. to create, in use, a cylindrical rotating layer of stock adjacent the inner wall of the screen wherein elongated solid particles are orientated tangentially to the screen so as not to flow through the screen perforations. Filtered liquid is removed by duct 18, whilst a valve controlled duct 24 communicating with a trough 23 at the bottom of the screen continually removes a portion of rejects-rich stock, which may be further screen after dilution or recyled to the inlet. Solids fall from the screen and are periodically collected in hopper 26 by operation of manually controlled valve 27. Helical rib 40 on the inner surface of the screen channels the flow of stock helically down the screen. The vanes 35 are mounted normally to 'the helical rib. The screen perforations are circular of 0.062 inch diameter and in a number to provide 10-15% open area. In a further embodiment (Fig. 2 not shown), the perforations are in the form of elongated slots of 2 inches in length and in a number to provide 5% open area and the helical rib on the inner screen wall is omitted.