Dravo Corporation

John R Lohr

Ira W Lakin

Edward A Fenton, Jr

David A Schreiber

Joseph H Stein

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. The mold is movable and is mounted on, and is essentially supported by, the piston by a frame which adjusts for mold droop to assure reregistry of the piston with the sealing and collecting ring following withdrawal of the piston for charging the mold with slurry. The movable molds of opposed horizontal press units acting on opposite sides of a vertical wall are actuated by angularly distributed overlapping hydraulic cylinders to form a compact double press. The rate of flow of pressurized hydraulic fluid acting on the pistons is increased after the bridges have formed over the drain openings and the hydraulic pressure acting on the two pistons is permitted to vary within preset limits to speed up production. Interchangeable platens, molds, pistons and sealing and collecting rings make possible rapid adaptation for a particular slurry.

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Pittsburgh, PA, United States of America

John R Lohr