| 摘要 |
965,337. Backwashing of filters. J. MULLER. May 10, 1962 [May 12, 1961], No. 18007/62. Heading B1D. If one of two edge filter elements 1, 2, Fig. 5, (e.g. 1), becomes clogged, inlet pressure forces a piston 40 to the right until a spring-loaded toggle lever 47 turns a valve about its spindle 30, and, by chain wheels 29, 27 and a chain, a lower valve. In these positions unfiltered liquid continues to pass from inlet 14 to chamber 8 inwards through element 2 to chamber 10 and to an outlet (not shown), whilst unfiltered liquid now gains access to the lower end of a cylinder 16, raising a piston 17 to force previously-collected filtrate into chamber 9, outwards through element 1 and to discharge through a tube 26. Rods 50, 51 are raised by the piston near the end of its upward stroke to restore the valves to normal position, where liquid flows through both elements in parallel. In Figs. 1 to 4 (not shown) the operation of the valves is not automatic. In Fig. 7 a pipe 75 communicates with the outlet chamber of two filter elements and on clogging of them a bellows 73 is allowed to expand, thereby releasing a rod 74 from engagement with a lever 77, 62, pivoted at 55 to the casing. The lever raises valve 66 to close inlet 68 and permit the region around the filter elements to communicate via opening 67 with a discharge duct 72. Thereupon the helical spring shown on the right raises a piston, and with it its hollow piston rod, to force filtrate previously stored above the piston outwards through the filter elements and to duct 72. Near the end of its travel the piston also raises an inner member 59 which pivots a bar 57 about the pivot 55 and hence by a toggle spring 63 restores lever 77, 62 to the position shown, where it is re-engaged by rod 74. The piston is then depressed once more in readiness for the next backwashing operation. In Fig. 8 (not shown) the bellows is replaced by a differential piston and in Fig. 6 (not shown) by a manually-operable spring trigger. In Fig. 9 filtrate flows during filtration through a small hole 95 in a non-return valve 96 to force a piston 92 very slowly downwards. At a certain position bar 87 switches valve 66 by means of toggle spring 88 and lever 86 to initiate backwashing, whereupon piston 92 is raised by spring 94 and valve 96 opens. Eventually the relative positions of bar 87, spring 88 and lever 86 are as shown, where valve 66 is in its normal position.
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