GB760915A - Improvements in filters for liquids - Google Patents

Abstract

760,915. Filters. A.P.V. CO., Ltd. Dec. 4, 1953 [Nov. 12, 1952], No. 28542/52. Class 46. Each element may comprise an inner ring 4, Fig. 1, having openings 4<SP>1</SP> and connected by fingers 3 thinner than the rings to an outer ring 5 having openings 5<SP>1</SP> so that when a stack of such elements is compressed between plates 7, 10, Fig. 4, with the spaces 2 aligned, liquid introduced at S<SP>1</SP> finds its way through openings 4<SP>1</SP> into alternate spaces 2, is filtered by circumferential passage between the fingers 3, (see Fig. 1A), and passes from the other alternate spaces to an outlet chamber D<SP>1</SP>. The inner plate 7 is provided with a flange 8 having openings 13, one opposite each opening 5<SP>1</SP>, and a hollow spigot 6 having openings 12, one for each opening 4<SP>1</SP>. Backwashing may be effected by discharge of filtered liquid from one set of aligned spaces 2 to an adjacent set from which the liquid passes through a slot 18 into the passage 17 of a rotary distributer 16 connected to a pressure lower than that obtaining in D<SP>1</SP>. All the spaces may be cleaned in turn by rotation of the distributer 16 by the device shown in Figs. 5 and 7. For an axial flow filter the openings 4<SP>1</SP>, 51 are not provided, in which case the fingers 3 may be narrower. Flow is then from an inlet chamber 21, Fig. 5, through openings 19 in the plate 7 aligned with the spaces 2, and out through openings 20 in the plate 10. For backwashing, liquid is conducted away from one opening 19 by a hollow arm 25 mounted on a hollow spindle 24 communicating with a low-pressure chamber 28. The arm 25 may be moved intermittently from one opening 19 to the next by pawl 31 engaging a ratchet wheel 30 secured to the spindle, the pawl being actuated by a cam 35 on a shaft 36 rotated continuously by a motor 40.