Screen comprising a travelling endless screening band

Claim 1

A screen comprising a travelling endless screening band defining a loop and having a longitudinal direction of movement and including a plurality of screening panels connected to one another in succession substantially perpendicularly to the longitudinal direction of movement, each of said screening panels including a substantially plane chassis, and a screening element carried by said chassis, said screening elements forming relative to a general plane of said chassis part-cylindrical projections extending parallel to the longitudinal direction of movement, generatrices of the part-cylindrical projections being parallel to the longitudinal direction of movement, the improvement wherein the screen is adapted to filter water flowing from outside to inside the screen, and there are means for washing the screening band disposed inside the loop defined by said screening band in a position to preclude interference with movement of said screening band, said means for washing said screening band comprising a washing manifold spaced inwardly and beyond the path of movement of said chassis and lying generally perpendicular to the direction of movement, said washing manifold including a plurality of nozzles arranged in first and second rows staggered with respect to the direction of movement, a first plurality of said nozzles being directed at a first oblique angle relative to the general longitudinal plane of the screen and a second plurality of said nozzles being directed at a second oblique angle relative to said general longitudinal plane opposite the first oblique angle, whereby respective ones of said first and second pluralities of nozzles are in crossed relationship for washing respective surfaces of said projections.