THOMAS B ZUGATES
Engineers in Pittsburgh, PA

5198125, Mar 30, 1993

Apr 3, 1991

7/679726

Lawrence A. Coudriet - Sewickley PA
Thomas B. Zugates - Pittsburgh PA

B01D 2104

210803

An upper carriage floats on the surface of a settling pond or tank of liquid containing sedimentation settled out to form a bed of sludge in the bottom of the tank. A scraper assembly is suspended from the upper carriage by flexible cables or chains to a preselected depth in the tank. Scraper blades supported by the scraper assembly extend downwardly into contact with the sludge bed. The carriage is propelled on a looped cable across the surface of the tank and applies a tractive force through the suspension cables to the scraper assembly. As the submerged scraper assembly advances, the scraper blades apply a shear force to dislodge the sludge from the bed and direct the sludge to a pump carried on the submerged scraper assembly. The dislodged sludge is pumped through a hose from the tank. In response to an excessive shear load applied by the sludge bed resisting forward movement of the scraper blades tending to force the leading edge of the assembly to move downwardly, the length of the leading cables is shortened to raise the leading edge to a position to permit continued shearing action of the scraper blades.