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UDC 628.16.067.1

Filatov A. I.

On some specific features of calculating drainage-distribution systems of large area rapid filters

Summary

Two main methods of calculating drainage-distribution systems for uniform washing of rapid filters are known: as regards the relation of the total surface area of drainage slots to the filter area and as regards the so-called relation of the total surface area of drainage slots to the cross-sectional area of the collecting manifold. The second method seems to be more consistent since it provides for the direct link between the values of the recoverable dynamic pressure in the pipes and the total head loss in the drainage required for the uniform filter wash. When using this method for calculating large area filters it is suggested to take into consideration the head loss at the sudden expansion of the cross section of the wash water flow at the head of the central (side) canal.

Key words

rapid filter , drainage-distribution system , pressure losses , wash uniformity , central canal