| 摘要 |
<p>1457515 Filter beds P FOODY 23 May 1974 [24 May 1973] 24994/73 Heading B1D Water to be filtered flows horizontally through beds 11, 12 and 13, which comprise successively finer aggregates, and the beds are cleaned by forcing wash liquid and/or air to flow upwards through the beds. Confining screens 14-117 have upper impervious portions enclosing spaces 27 which allow the beds to fluidise when washed. Wash fluid is directed from conduit 20 to individual beds, and further wash fluid may be delivered to nozzles 28 which may extend into one or more beds. The beds shown are of flat form, but in Fig. 2 (not shown) liquid flows outwards through a series of concentric beds, enabling finer beds to have greater flow cross-sections. Fig. 3 (not shown) illustrates apparatus similar to Fig. 1 but with beds spaced apart and removable shutters (52) to isolate a bed being washed from its neighbours.</p> |
