1, Backwash is automatically formed and stopped. Here are two issues worth noting, first, the process of backwashing, with the decline of the water level of the flushing tank, flushing intensity gradually reduced, which is quite favorable flushing effect; the second is the backwash process, diaphragm filter press filter Constantly into the water, and with the backwash water discharged together, resulting in loss of water.
2, Diaphragm filter pressless filter automatic backwash only in the filter head loss reaches the end of the cycle allowed head loss value can be carried out. If the filter head loss has not yet reached the allowable value, and for some reasons need to backwash ahead of time, you must use forced backwash. For this purpose, a forced flushing device is provided in the valveless filter, which is a pressure pipe inserted in the upper part of the siphon auxiliary pipe connected to the suction pipe. To be forced backwash, open the inlet valve on the pressure pipe, high-pressure water will quickly siphon air pumped away, so siphon formation.
3, Variable head speed filtration. During the filtration process, the water level in the siphon rising pipe increases with the increase of the filtration time, the increase of the suspended solids in the filter layer and the increase of the filter resistance. Therefore, in the case of the same amount of water, it was changing head constant velocity filtration state, until the start of backwash.
4, Using a small resistance distribution system. Due to the structural characteristics of the valveless filter, a low water head backwash is usually used, so only a small resistance water distribution system can be used. In thermal power plants, the majority of valveless water distribution system for the grid.