Abstract: The drain openings in movable and fixed platens in a press unit are wider than the largest praticle in a slurry to be dewatered and are formed by arcuate ribs dimensioned to resist the transverse forces developed as the granular particles from bridges across the slotted drain openings in rendom order. Liquid expressed through the movable platen is directed radially outward through a subplaten, passes back through the clearance between the piston carrying the movable platen and the mold wall and is discharged through a sealing and collecting ring having a series of annular grooves which communicate with longitudinal radially extending slots having longitudinal bores at the radial extremity thereof which direct the liquid to an annular passage for discharge.