| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a sand filter which can perform high efficiency operation suitable to the volume of water to be treated while maintaining continuous cleaning. <P>SOLUTION: A plurality of air lift pumps constituted of a compressor 13, air feeder pipes 11 and 12 and air lift pipes 9 and 10, are installed. The operation and stopping of each air lift pump are switched by controlling a switching valve 23 in response to the flow rate of water to be treated which is measured by a flowmeter 25 and an SS (suspended solids) concentration of the water to be treated which is measured by an SS densitometer 26. <P>COPYRIGHT: (C)2012,JPO&INPIT |
