Continuously operating density or thickness filter

摘要

1,058,349. Filtering. SOC. FIVES LILLECAIL. Dec. 1, 1965 [Dec. 2, 1964], No. 51046/ 65. Heading BID. A filter comprises a tank 1 containing a plurality of filter elements 10, which are sequentially connected to a source of suction to effect filtration of liquid in the tank and to a source of pressurised liquid to effect reverse flow cleaning, the elements being arranged in 'compartments' which communicate at the bottom of tank 1, whereby filter cake washed from elements being cleaned is prevented from reaching adjacent elements on filtration flow. In Figs 1-3 and 4 (not shown) elements 10 each consist of a flat frame, divided by an impervious partition (21) into two cells 24, 25 with separate outlet connections, each cell containing a perforate sheet, supporting a sack-like filter cloth which is stretched over the whole frame and secured in a channel thereof by a peripheral cord (30). The tank 1 is partly divided by circumferential and radial walls 34, 7, but the 'compartments' referred to above are formed by the partitions (21) dividing each element. Four cells of four adjacent elements 10 of the outer circumferential rows are commoned to each pipe 31, and four cells of three adjacent elements of the central row to each pipe 32. Various pipes 31, 32 are connected to a power-driven rotary valve (11) which connects groups of cells successively to two separate sources of suction (13), (14) and to a supply (15) of pressurised liquid, which may be returned first filtrate, removed filter cake falling to the bottom of tank 1 where it is directed by rotary scrapers (18) to outlet (36). Valve 11 may be in series with a quick acting solenoid valve, operated when valve 11 is in full communication with successive ports, to provide a sudden flow of reverse-flow liquid instead of a gradual increase. Valve 11 may be replaced by an array of separate sequentially actuated valves. Elements 10 may be inclined to the vertical. In Figs. 5 - 7 (not shown), single elements of hollow annular form (Fig. 7) are each located in a separate haxagonal compartment of the tank, the compartments being formed by partitions (41) which extend to short of the tank floor. Each element is carried by its outlet pipe on an individual cover (50) mounted over a hole in the tank top. Each element (43) could be replaced in Figs. 5, 6 by a group of elements of cylindrical form (Figs. 8 - 11, not shown). In Fig. 8, a cylindrical cloth bag (65) is supported by an array of springs (63) stretched between end pieces (60). (61). Alternatively, one end piece (61) could be slidable and springs (63), under compression, would stretch the cloth bag.