Means for suppressing edge leakage in filter presses

Claim 1

A liquid filter for disposition between adjacent plates of a filter press and having axially aligned central flow path openings and opposed seal faces encircling said openings, comprising a disc of predetermined size and shape of a sheet of filter media including fibrous cellulose and non-compressible mineral particulate material of predetermined concentration and particle size; means for substantially eliminating edge learage due to wicking when said filter is disposed between said plates, said means, consisting of a flange portion extending outwardly from the flow path openings when retained between plates of a filter press, and said flange being dry pressed prior to use, to a density corresponding to a thickness approximately one half of its original thickness, said flange having sufficiently smooth surfaces to be engaged by and forming sealing interfaces with the opposed seal faces of the filter press plates to suppress edge leakage.