Method and apparatus for cleaning a filter apparatus

摘要

A method and apparatus for cleaning a filter apparatus of the type having an atmospherically vented tank, a rotatable filter frame in the tank having filter material thereon providing one or more filter effluent compartments on the filter frame. An influent line supplies liquid containing suspended solids to the tank and a filtered effluent outlet communicates with the filter effluent compartment, and a spray wash device including spray nozzles is operable during a wash cycle to direct high pressure liquid spray at a side of the filter material on the filter frame in a spray zone. An air tight hood is mounted inside the tank and extends above the upper periphery of the filter frame to an open lower end below the spray zone. The hood is vented to atmosphere during a filter time to allow liquid influent in the tank to flow into the hood and immerse the filter frame, and air is supplied to the hood during the wash cycle at a pressure sufficient to pneumatically depress the liquid in the hood to a level below the spray zone.