primary common objective and unique property of the grid element geometry is creation of sharply curved streamlines of the flow 502 passing through the gaps between the elements in general smaller the radius of the curvature of the streamline is the smaller the size of the particle that will be separated from the pass through flow and will remain on the face or concentrated side of the separator screen the secondary common objective and unique property of the grid element geometry is creation of least obstructed low drag flow conditions for the sweeping flow on the face side 503 of the screen the separated particles remain on the swept side of the separator screen and they must travel along the face of the screen with the seeping flow 501 with the least amount of resistance in order to achieve these objectives all of the considered profiles must be asymmetrical with low drag streamlined properties in direction of the sweep flow and must provide a highly curved streamlines for the flow passing through the gaps between the elements for the purposes of this application the following nomenclature is applied to describe the orientations directions and sides of the screen elements the face side 503 is from where the mixed concentrated flow approaches the separator screen the clean side of the screen 504 is where the cleaned flow leaves the screen leading side 505 is facing the sweeping flow and trailing or after is side 506 where the sweeping flow leaves the profile consistent with this naming convention there are four quadrants of the profile leading face 507 leading clean 508 trailing face 509 and trailing clean 510 the geometry of the.