Patent ID: 8906233

Claim:
In an apparatus for separating grit from a liquid stream, said apparatus including a cylindrical separation chamber having an influent and an effluent flume for liquid with a cylindrical grit storage chamber disposed immediately below the separation chamber, said chambers separated by a transition surface having a centrally disposed opening therethrough for passage of separated grit to said grit storage chamber, a central flow drive comprising: a duct substantially cylindrical about an axis and adapted to be supported in said separation chamber above the centrally disposed opening in said transition surface; a plurality of vanes adapted to be secured between said duct and the transition surface in an upwardly extending orientation and spiraling outwardly from said duct in the same direction as liquid flow within the separation chamber; a propeller supported for rotation in said duct about said duct axis, rotation of said propeller drawing liquid in said duct upwardly; and a drive for rotating said propeller about said duct axis.