| 摘要 |
1,212,869. Filters cleaned by backwashing. PADDOCK OF CALIFORNIA Inc. 1 Dec., 1967 [2 Dec., 1966], No. 54845/67. Heading B1D. A tank 1 for a filter element comprises a single influent line 10 and a single outlet line 11; and a valve 15 which, as shown, connects line 10 to line 29, and connects line 28 to line 11 respectively for backwashing, but which in a second position (Fig. 2, not shown) connects line 10 to line 28 and line 29 to line 11 for normal forward filtration flow. As described, a bag (41, Fig. 1, not shown) is connected downstream of line 11 for filtering the backwash before returning it to a swimming pool; it may be bypassed during normal forward filtration. The filter element comprises beds of granular material 16-19 of increasing coarseness. The liquids are distributed and collected by perforated "cartwheel" members 30, 33. In another embodiment, Fig. 6 (not shown), the filter elements are hollow mesh disc members (61) covered with diatomaceous earth (64) and mounted on a fixed hollow shaft (59). Valve member 20 pivots about axis 22 and is surrounded by an O-ring 23 which sealingly engages in grooves 24 in the valve casing. |
