| 摘要 |
Backflushing filter, esp. open or closed rapid filter for water prepn., uses combined water and air sparing to backflush and having base supporting layer under the filter sand layer. On the base of the filter vessel air and water distribution pipes are located having slits which are smaller than the particle size of the filter bed. Their flow resistance is so arranged so as to give a closely knit and uniform distribution of the backflushing medium without the supporting layer or filter bed and ingress of sand into the tubes is prevented without further aid. Inside and along the length of the air distribution pipe is a second pipe having calibrated openings for the air. The pipe can be divided internally into separate chambers. The filter is of esp. use for preparing drinking and general purpose water. Such filters where backflushing is used, require special methods to ensure adequate distribution of the air and water, which can include a special intermediate floor to the bed called a jet tray. The system gives a very much simpler construction. |
