A Multi-Grade Filter (MGF) is a pressure filter with several layers of filter media — typically graded gravel, coarse sand and fine sand, and sometimes anthracite. It strips out mud, sand, silt and heavy suspended solids so that they do not clog or coat the downstream equipment, especially the porous bed of an Activated Carbon Filter (ACF).
Where an MGF is used
- First filtration stage in water treatment plants for borewell or surface water
- Pre-treatment ahead of ACF, softener, UF and RO plants
- Tertiary treatment of treated sewage and effluent before reuse
- Commercial buildings, hotels, hospitals, townships and industries
How it works
Water flows downward through the media layers, and suspended particles are trapped in the bed. When the pressure drop rises, the filter is backwashed — water is reversed upward to lift and clean the media — and then rinsed before returning to service. Operation can be manual (multiport valve or valve nest) or automatic.
Construction
- FRP or MS (epoxy-painted or rubber-lined) pressure vessels
- Graded media selected for the raw-water quality
- Pressure gauges, sampling points and backwash arrangement
We often supply the MGF together with an ACF as a single filtration package. Share your flow rate and raw-water analysis and our engineers will size the system.
