Filter cartridge for street storm water drain has coarse upper and fine lower filters over perforated plate

摘要

A street storm water drain with an inlet to a multi-stage filter (15, 16) within a filter cartridge (14). Water flows through the filters in alternate radial directions. The filter has an inner annular chamber (18) closed at the bottom (38). The upper filter (15) is a coarse filter and the lower filter (16) is a fine filter over a perforated base plate (29).