Floating sludge skimming device - with revolving overflow weir lowered within leeward sector

摘要

A floating sludge clearance system for circular basins in sewage treatment plant uses a slowly revolving raker bridge, carrying an overflow weir which is periodically lowered, so that the fluid with the sludge can be removed by a pump. A weather cock measures the direction of the wind and locates limit switches within a sector of 60 deg. on the leeward side to lower the wier only within this sector. This concentrates the clearance operation to a sector where the floating sludge as accumulated so that it is raked off with a minimum of water.