公开(公告)号：US3392835A

公开(公告)日：1968-07-16

申请号：US44838665

申请日：1965-04-15

Applicant: BRASCO SA

Inventor： JEAN-JACQUES ASPER

IPC: B01D29/11 ,  B01D29/15 ,  B01D29/52 ,  B01D35/12 ,  B01D36/02 ,  B01D36/04 ,  B01D37/02

CPC classification number: B01D29/15 ,  B01D29/114 ,  B01D29/52 ,  B01D29/6438 ,  B01D29/668 ,  B01D29/885 ,  B01D29/904 ,  B01D29/94 ,  B01D35/12 ,  B01D36/02 ,  B01D36/04 ,  B01D36/045 ,  B01D37/02 ,  B01D2201/0453 ,  B01D2201/287

Abstract: 1,052,157. Automatically-cleaned filters for liquids. BRASCO S.A. April 14, 1965 [April 17, 1964], No. 15986/65. Heading B1D. Unfiltered liquid introduced at 5 passes outwards through a perforate screen 6 into a common admission chamber 3 and passes thence through annular passages 12a &c., each surrounding a tubular member 10a &c., acting as a holder for a porous filter element 11a &c., depending into a sector-shaped cell 1a &c. From all but one cell the liquid filters inwards through the element to reach a common exit chamber 4 having an outlet 7. One element at a time (e.g. 11a, as shown) is cleaned by engagement of a rotating cam 16 with the stem 15a of a valve 14a permitting communication between cell 1a and a common discharge chamber 8 having an outlet 9. The cam is so shaped that the valve is first suddenly opened to its maximum extent and for a short time only, then suddenly partially closed, being maintained in this partially closed position for an appreciably longer time, and then closed for the remainder of the cycle. In the first of these stages, a transient pressure-reversal occurs across the filter element, sufficient to dislodge the cake without much loss of filtered liquid; in the second stage the extent of valve opening ensures pressure-equalisation across the element, so that the element is washed by flow of unfiltered liquid along it from annular passage 12. In the third stage normal filtering occurs, so that where twelve elements are provided the first two stages together occupy only one twelfth of the cycle for any one element. A more complex embodiment is described, its main differences from Fig. 1 being (a) the provision of several (e.g. seven) filter elements per cell; (b) the provision of a woven sheath on each element as actual filtering surface, of such a size that it has one or more folds under inlet pressure, and blows out to break up the cake on pressure reversal; (c) the provision of a resilient disc, with a central hole, in the upper end of each tubular member, so arranged that the hole is enlarged by liquid flow in the "backflush" stage only, to provide greater backflow. Where a granular filter adjuvant is used, the outlet 9 may be connected to a hydrocyclone or similar device, (Fig. 10, not shown), from which a "residue" fraction and an "adjuvant" fraction are discharged separately, the latter preferably being re-circulated by a pump to inlet 5. Further cams may be provided to effect simultaneous cleaning of several cells.