SCREENING APPARATUS

摘要

A mixture of liquid and solid sewage flows in a stream along a channel (2) in the direction from right to left as seen in the Figure. A screening apparatus includes an endless screening belt (4) located with its lower inlet region in the sewage stream. The belt (4) consists of pivotally connected screening elements (12) made of perforated plate. Each screening element (12) consists of a shorter part (14) and a longer part (16) connected at an acute angle to one another. In operation, the belt (4) travels anti-clockwise causing solid sewage greater than the size of the perforations to be carried upwardly on the shorter parts (14). The liquid sewage effluent drains from the screening elements (12) as they ascend. When each screening element (12) reaches the upper region of the belt (4) the screening element tilts in a clockwise direction to release the solid sewage which drops to a screw conveyor (30) which conveys the solid sewage to a desired location. The upper region (22) of the belt (4) extends upstream of the inlet region of the belt (4) so that any solid sewage spilt from the upper region of the belt (4) which is not collected by the screw conveyor (30) falls back into the channel (2) upstream of the inlet region of the belt (4). This arrangement reduces the risk of solid sewage entering and polluting the cleansed liquid sewage effluent downstream of the conveyor belt (4).