Filtration performance of combined pre-pump and post-pump mesh filters
To investigate the filtration performance of combined pre-pump and post-pump mesh filters,the pre-pump and post-pump mesh filters were connected in series.The influence of different inlet water flow,sand content and mesh size on the head loss and sand interception rate of combined filters was carried out through indoor prototype tests,and the test results of the combined filter were compared with the head loss and sand interception rate of single mesh filters.The results show that the head loss of the combined filter under clear water condition is positively correlated with the inlet water flow.Un-der the muddy water condition,head loss increases with the increase of inlet water flow rate and mesh size.Under the condition of inlet water flow of 130 m3/h,influences of the inlet water sand content on the initial head loss and total peak head loss are relatively small.Through range analysis,in descending order of the influence degree of various factors on the sand interception is screen aperture,sand content and inlet water flow.The optimum combination of filter parameters is determined to be the pre-pump filter with mesh number of 60,the post-pump filter with mesh number of 100,130 m3/h in-let flow rate and 0.18 g/L inlet sand content.When the flow rate is 110-150 m3/h,the maximum peak head loss of combined mesh filter is 41.51%and 39.58%higher than that of single pre-pump or post-pump filter,respectively.The results of the study have positive significance for application and promo-tion of the combined mesh filters.