GB139991A - Improvements in and relating to devices for filtering fluids - Google Patents

Abstract

139,991. Atkins, F. K., and Atkins, E. F. July 8, 1919. Leaf filters; filter-presses; filters having sheet filtering-material.-Plough-like members operating in the manner of a lathe tool are used to break up and remove cakes formed under pressure between spaced filter plates. The apparatus shown in Fig. 1 comprises cellular filter plates 22 covered with cloth and spaced apart on a shaft 19 in a casing 11. Filtered liquid is led away from the interior of each filter plate through a separate conduit 90, the conduits 90 corresponding to alternate filter plates discharging into conduits 57, 58 respectively, formed in a shaft 24. When the cakes are to be removed, the shafts 19, 24 are rotated by means of bevel-gearing 26, and a shaft 32 carrying ploughs 52, Fig. 4, is slowly turned so that the members 52 are brought between the plates to break into the cakes and push the solid matter to the periphery, from which it falls to the bottom of the casing and is discharged through a pocket 67 normally closed by a plug. The shaft 32 is turned bv a lever connected to a cam 38 rotated by worm gearing from the shaft 27 of the bevel-gear 26, the worm gearing being provided with clutch mechanism which is automatically disengaged. The filtered liquid is discharged from the conduits 57, 58 through conduits 60, 59 respectively, these latter having suitable connexions so that steam, hot or cold water, compressed air, or other fluid for treating the formed cakes may be delivered to, and discharged from, the interior of alternate plates. The base 10 of the casing may be provided with a recess fitted with suitable supports and a filter cloth to form a filter plate, a cutter 21 with plough members 77, Fig. 5, being provided on the shaft 19 to remove the cake formed on this plate. After the cakes are broken up, the cloths may be cleaned by rotating the plates with the ploughs at rest across them, a fluid under pressure being supplied to the interior of the plates. A cleansing-fluid may also be supplied through a pipe 78 having small outlet pipes 79 between each pair of plates. Each conduit 90 is provided with a testing-valve above its connexion with the conduit 57 or 58, and each connexion has a valve 65. Figs. 11 and 13 show the application of the invention to a filter-press mounted on trunnions so that filtration may take place with the plates vertical, and the press may be turned so that they are horizontal for the removal of the cakes. The plates are annular, and a cylindrical space is left in the centre of the press, through which passes a shaft 117 mounted eccentrically in bearings in rotatable members 103, 109 in the heads of the press. The member 103 has a central aperture 104 closed, during filtration, by a gate 105. The shaft 117 is provided with cutters 116, which are situated, during filtration, entirely within the central cylinder. For discharge of the cakes, the headers 103, 109 are rotated so that the shaft 117 is carried round, and the shaft is also given a relative rotation which causes the cutters to break into the cakes, pushing the solid matter into the cylindrical space, from which it falls through the aperture 104. A thin metal tube may surround the shaft 117 and cutters during filtration.