Patent ID: 7879247

Claim:
A method of filtering with a filter apparatus, said filter apparatus comprising: a plurality of filtering regions disposed essentially horizontally and above one another in the direction of a central filter axis; at least one central distributor conduit being associated with said filtering regions; at least one common channel for delivering unfiltered liquid to be filtered; a pump for pumping said unfiltered liquid; at least one common channel for removing filtered liquid from said filtering regions; and said filter apparatus comprising a filter layer that is disposed at a filter element, said filter layer being configured to serve to produce, for the purpose of precoating, at least one precoat layer, and said filter layer separating a filtrate collecting space that discharges into said filtrate channel from a sludge compartment that is positioned above said filtrate collecting space; said filter apparatus further comprising an annular feed channel disposed about the central axis of said filter apparatus; said annular feed channel comprising: at least one entrance opening for said unfiltered liquid and an exit opening into said sludge compartment, which said exit opening is disposed at a larger first radial distance from the central filter axis, and said at least one entrance opening is disposed at a smaller second radial distance from the central filter axis; a plurality of valve apparatuses being configured and disposed to control the exit stream of filtrate from said filter elements; and each filter element and/or a group of filter elements being associated with a corresponding one of said valve apparatuses, said method comprising: continuously monitoring, with a computer control unit, a plurality of pressure sensors in said filter apparatus to determine pressure drop of each filter element and/or a group of filter elements; and filtering unfiltered liquid through said filter elements while continuously adjusting the pressure drop in each filter element and/or a group of filter elements so that the pressure drop is substantially the same for each filter element and/or group of filter elements by automatically adjusting, with said computer control unit, said plurality of valve apparatuses, and thereby minimizing energy consumption by said pump and maximizing filtration.