1. Work filtering
During normal operation, the water flow steering valve is open.  After the water to be treated passes through the filter screen, fine particle impurities and suspended substances in the water are deposited near the sewage outlet due to inertia principle.
2, flushing sewage
During normal flushing, the water flow steering valve is open.  When the filter screen intercepts a certain amount of fine particles, impurities and suspended substances in the water, the valve on the drain outlet is opened, i.e. the impurities adhered to the collecting section of the filter are washed until the discharged water is clear.  Then close the valve on the drain outlet to enter the normal working state.
3, backwashing sewage
When backwashing, the water flow diversion valve is closed and the drain valve is opened. At this time, water flow is forced to enter the interlayer between the outer side of the filter cylinder and the shell from the mesh of the inlet section of the filter cylinder, and impurities adhered to the mesh are backwashed from the outer side of the filter cylinder in reverse direction to achieve the purpose of cleaning the filter screen.  As the steering valve is closed, the flow rate of water after passing through the recoil valve increases, and the backwashing effect is good.