The working principle of shallow sand filter

1. Washing filter state When the system is in the filtering state, the unfiltered water is evenly distributed through the unique water distributor, and the water passes through the packing layer in the filter in a laminar flow state. When water flows through the packing layer, impurities are trapped within the packing layer.

There are a plurality of evenly distributed water collectors at the bottom of the filter, the filtered water is evenly collected and drawn out, and the advective filtration can make the filter filter at a high flow rate, and still achieve a better filtering effect. 2. Backwash filter status As impurities build up in the packing layer, the internal head loss will continue to increase.

When the head loss of the inlet and outlet water reaches the set value, the system will automatically activate the constant pressure device to switch to the backwashing state. When the backwashing of this unit is completed, the hydraulic valve changes the direction of the water supply to realize the backwashing one by one, which is more convenient Clean up accumulated impurities. When the system is in the state of backwashing, the filtration continues, the standard unit sand tank to be backwashed is not filtered, and other standard unit sand tanks in the system are still filtering.

Part of the filtered clean water is used to backwash the standard unit sand tank, and the rest is still sent to the user. The backwash sewage is discharged through the backwash drain of the hydraulic valve. In the high-speed sand tank automatic high-efficiency filtration system, the special water collector design can make the fillers rub each other, maximize the backwashing efficiency, reduce the required backwashing water (clean water), and at the same time when backwashing No runaway phenomenon.

The backwashing of a standard unit sand tank is 2 minutes, the backwashing is over, the internal pressure head loss of the standard unit sand tank is reduced to a reasonable range, the constant pressure device gives a recovery signal, the hydraulic valve returns to the filtering state, and the next standard unit sand tank It is ready to enter the backwash state. Poolking.