Trade-off between hydraulic performance and filtration level of screen filters under different inlet pressures and screen apertures

Abstract

Screen filters (SFs) are widely used for water purification. Particles adhered to the SF surface can block flow channels and potentially result in changes in the SF filtration level. However, the impact of blockage on the actual filtration level and hydraulic performance of SF remains uncertain. This study investigated the effects of five inlet pressures (0.02, 0.04, 0.06, 0.08 and 0.10 MPa) and seven screen apertures (125, 150, 180, 210, 250, 300 and 355 μm) on the filtration effectiveness, head loss and flow rate of agricultural SF. The results revealed that blockage reduced the SF pore size by 16%-45%, increasing the filtration level. An increased inlet pressure accelerated SF blockage and increased the filtration level, reducing the pore size by 14%-35% at 0.10 MPa, compared with 0.02 MPa. However, an improved filtration level led to greater head loss. A trade-off between screen aperture and head loss was identified, suggesting the need for practical SF filtration level adjustments. For the 210 μm filtration requirement, the use of a 250 μm filter at 0.06 MPa or a 300 μm filter at 0.08 MPa achieved the desired aperture while minimizing head loss. Compared with selecting filters solely on the basis of pore size, adjusting the filtration level increased the average flow rate by 23% and decreased the average head loss by 25%. This study provides significant insights into SF filtration grade changes and offers a strategy to reduce filtration energy consumption