| 摘要 |
A water treatment plant comprises a treatment tank (1) at atmospheric pressure to which raw water is supplied by a first pump (7). A mixture of air and the raw water is fed to the upper part of the tank to flow downwards through a filter (13) into a collecting magazine (15). A pressure tank (17) is connected to the magazine (15), and the appts. also includes a filter-washing mechanism (22,23,30,31). A second pressure-controlled pump (18) feeds filtered water from the magazine (15) to the pressure tank. The filter-washing mechanism includes an evacuating device above the filter. It consists of a syphon (30) whose suction end is placed between a lowest level in the tank for activating the first pump, and a highest level in the tank for deactivating the pump. It also includes an overflow (31) whose opening is above the highest level in the tank. A control system (24) keeps the second pump deactivated for long intervals or for short periods when a connecting line (22) between the pressure tank (17) and magazine (15) is opened. Clean water is fed from the tank (17) and the magazine (15) up through the filter (13) to raise the level in the tank to the overflow. This enables precipitates in the tank to be discharged through the syphon and overflow. |
