Extn. of sediment from settling tank or upstream of dam - using head pressure displacement of retained liq. to suck sediment into discharge pipe

摘要

A method and an installation for the extn. of sediment e.g. from a settling tank or retention zone upstream of a dam is new. The installation comprises an extn. pipe which extends through a layer of sediment from an inlet end immersed in liq. above the sediment to a discharge end outside the tank or retention zone. The length of pipe buried in the sediment has one or more suction inlet apertures. When liq. is allowed to run through the extn. pipe, sediment is sucked in through the apertured and delivered in suspension in the liq. via the discharge end. Pref. the extn. pipe inlet end is at a higher level than the discharge end, the buried section of pipe is horizontal and the suction inlet apertures are on the underside of the pipe, partic. within a sector +-25 deg. on each side of a vertical, median plane through the pipe. Process can also be used for hydraulically conveying a powder in suspension in a liq. The system is simpler and cheaper than those employing mechanical extractors, suction pumps etc. The flow rate can be set so that max. solids are removed per unit of liq., The setting can be predetermined by means of a mathematical model.