Backwash Filter mainly contains cylinder, filter element, backwashing mechanism, electric control device, reducer, electric valve and differential pressure controller, etc.
Backwash filter can be continuous filtration and automatic filtration, cleaning and discharging as well. However, the working principle and cleaning mechanism is different from self-cleaning filter.
Filtering state:
When the water passes through the filter's coarse mesh, it enters the fine filter chamber, and the impurities gradually accumulate on the fine mesh to form a layer of filter cake.
As a result, a pressure difference is generated between the inside and outside of the fine mesh. When the pressure difference reaches a preset value, the controller makes the hydraulic valve working and water flows out from the hydraulic motor chamber through the hydraulic valve.
Backwashing state:
When the hydraulic valve is opened, the pressure in motor chamber, the collector and the suction nozzle drops to an extremely low point.
This causes a pressure gradient between the fine mesh's outer surface (clear water) and the inner surface (water) of the fine mesh opposite to the suction nozzle. The recoil movement generated by this pressure ladder cleans the filter screen.
When water and impurities pass through the hydraulic motor, the collector will be turned, and the piston in the hydraulic cylinder is driven the collector to move axially.
Finally, when the impurities on the filter screen is backwashed, the pressure difference disappears. The flushing controller closes the hydraulic valve, and the piston returns to its original position. At this time, the entire system returns to the original position and waits for the next cleaning cycle.
