APPARATUS FOR DISTRIBUTING GAS AND LIQUID DURING CONCURRENT GAS/LIQUID BACKWASH IN FLAT BOTTOM FLUMES

摘要

A concurrent backwash distribution apparatus for a filter (11) having a filter tank (13) and a plurality of underdrain laterals (24) includes a baffle (10) positioned in a common main conduit (12) to define a secondary flume (14) between the baffle (10) and the underdrain laterals (24). The secondary flume (14) is in fluid communication with common main conduit (12) and the underdrain laterals (24). The baffle (10) has at least one flume liquid metering orifice (16) located adjacent a bottom of the buffle (10) so that it is below a gas liquid interface (23) in the secondary flume (14) during concurrent gas/liquid backwash operations. A flow distribution plate (18) is positioned between the secondary flume (14) and the underdrain laterals (24), the flow distribution plate (18) having at least one liquid metering orifice (22) and at least one gas metering orifice (20). The baffle (10) may be an upstanding partition (26) or an L-shaped partition (30). The baffle (10) creates adequate room for low velocity flow of backwash liquid in flat bottom flumes, while at the same time providing clearance for flow of backwash gas.