Patent ID: 7670482

Claim:
A self-cleaning screen assembly for use in shallow water pumping, comprising: a rotatable drum comprising a screen for removing debris from water as the water passes into the drum, said drum being supported for rotation about a horizontal axis during operation; a suction chamber positioned within the drum and a discharge opening for discharging water out of the suction chamber to feed a suction pipe of a pumping unit, said suction chamber defined by a horizontally extending structure having an opening along a bottom portion of said horizontally extending structure and a plate positioned within said opening, said plate having a plurality of inlet openings arranged therein for receiving water from within a lower part of the drum; and a check valve assembly for allowing water to pass into the inlet openings of the plate during water pumping, and for preventing water from passing back through the inlet openings when the water pumping ceases to thereby maintain a prime in a pump above the suction chamber; said check valve assembly comprising a plurality of valve members arranged to move vertically within said suction chamber, each of said valve members comprising a valve stem and a valve face with said valve stem being slidably received in a support structure for allowing the valve member to move between a closed position in which the valve face covers a respective one of said inlet openings and an open position in which the valve face is displaced from its respective inlet opening, said valve members being arranged to move vertically upwardly from their closed positions to their open positions upon movement of water through said inlet openings into said suction chamber.