Expressing plate assembly for filter press

Claim 1

In an expressing plate for a plate-type filter press wherein flexible expressing sheets cover the opposite surfaces of a rigid core plate, the core plate has a peripheral frame portion, expressing fluid being fed between the core plate and expressing sheets, and aligned filtrate discharge openings are provided in the peripheral portions of the core plate and expressing sheets, the improvement comprising, fitting recesses in the opposite surfaces of said core plate around each said opening therein, a raised portion around each said opening in each expressing sheet on the inner face thereof facing said core plate and having a peripheral shape substantially conforming to that of said adjacent fitting recess to interfit therein, a seating ring recess around each said opening in each expressing sheet on the outer side thereof and smaller than said adjacent fitting recess, seating rings each having an opening therethrough and a peripheral shape substantially conforming to that of the adjacent seating ring recess and interfitting therein so that a pair of seating rings is disposed at each core plate opening one on each side of said core plate with said seating ring openings aligned with said core plate openings, means to clamp each said pair of seating rings together to clamp said expressing sheets to said core plate and maintain alignment of said openings, a plurality of ridges defining grooves therebetween which serve as filtrate passages on the outer face of each expressing sheet, and filtrate passage grooves on a part of the outer face of each seating ring substantially aligned with said grooves on said expressing sheets to be substantially continuous therewith.