The Delkor Gravity Filter uses sand as the filtering media and works on the principal of gravity filtration without any valve, pilot mechanisms, rate controllers, gauges and air compressors. These filters have two compartments - filtering section and wash water storage compartment.
Either single or dual grade sand is filled up in a pressurized vessel. Internally it is fitted with an inlet distributor and a bottom collecting system. Externally, it is fitted with frontal pipe work and isolation valves. Pebbles and gravels are provided as the bottom layer under the sand bed of uniform size for support. The Delkor Gravity Sand Filter are constructed in mild steel with suitable internal and external coatings, with units for drinking water applications being fully covered.
During normal operation, water gets filtered while travelling across the sand bed. During filtration, suspended solids gets accumulated in the filter bed and results in an increase in the differential pressure, causing water level to rise in the backwash pipe. When the water level reaches the top of the loop, siphon action starts and backwash begins. Wash water flows from the storage compartment through the sand bed and is discharged through the back wash pipe. A siphon breaker ends the wash cycle.
The Delkor Gravity Sand Filter mainly removes suspended impurities from the water source. Suspended impurities get trapped within the sand media when water is passed through the sand bed and clear water comes out as the product. Backwash of the filter is done to remove these entrapped impurities from the filter, once it reaches the specified maximum limit – as determined by differential pressure across the filter.