Water filtration installation

摘要

A channel 2 for transporting filtered water communicates with pipes 7 having nozzles 11 spaced along their upper surfaces and extending across a floor 1 supporting a filter bed surmounted by a body of water (not shown). Air and water are supplied simultaneously to channel 2 and thence via respective ducts 16 and 3 to each pipe 7 so that the nozzles 11 eject an air/water mixture for backwashing and air scouring of the filter bed. Air enters the pipe above a baffle 18 extending part-way along each pipe 7, and water enters below the baffle 18. Each nozzle 11 has a hollow stem 12 with an upper air inlet 21, water entering through the bottom of the stem.