GB1063724A - Improvements relating to presses for filtering - Google Patents

Abstract

1,063,724. Press filters for slurries. G. & J. WEIR Ltd. March 8, 1966 [March 19, 1965], No. 11712/65. Heading B1D. A press filter comprises a lowerplaten 11, 28 supporting one sheet of filter medium 33 and an upper frame comprising a top plate 15, sealing ring 18, 19 second sheet of filter medium 22 and diaphragm 20, the upper frame being pressed down in use on to the lower platen so that sheets 33, 22 form an envelope into which slurry is introduced by inlet 24, after which pressure fluid is delivered by inlet (23) through plate 15 (Fig. 4, not shown) above diaphragm 20 to press the envelope, filtrate draining from below and above sheets 33, 22 respectively by lines (29), (30), 31, 32 and outlet 25. The initial movement to close the press is effected firstly by rams 16, 17, then by inflating bag or bellows 13 through pipe 14, both these serving to lower plate 15. Diaphragm 20 is ribbed and rubber plate 28 is ribbed or slotted to facilitate filtrate drainage. After the pressing described above, the slurry may be washed and/or dried by water, solvent or compressed air delivered either by filtrate outlet 25 or slurry inlet 24. Bellows 13 may be partly deflated and reinflated during washing. Sheet 22 is permanently clamped between rings 18, 19, but sheet 33 may be an endless belt or an extended length of material entrained round rollers 34. Parallel cylinders 37 travelling on their piston rods 36 move two rollers 34, with the press opened, and this carries one section of sheet 33 out of the press where its cake is removed by scraper 38 or by water sprays. The movement may be reversed prior to reclosing the press, or alternatively two sections of sheet 33 may be used for alternate pressings, necessitating two scrapers 38 or sprays on opposite sides. The sheets 22, 33 may be cloth, felt or paper. A manual winding drum 35 is for tensioning sheet 33.