GB1466423A - Vacuum filter apparatus - Google Patents

Abstract

1466423 Valves ERIE DEVELOPMENT CO 22 March 1974 [28 March 1973] 12883/74 Heading F2V [Also in Division B1] In a rotary vacuum filter wherein successive axial groups of filtering sectors of respective discs are subjected to suction while immersed in slurry and after emerging therefrom to dry the resulting filter cake, the suction is applied from a single source communicating with a bell-like housing (31) on one side of a fixed valve plate 32 which is engaged by a rotating wear plate (33) having a port in communication with each respective sector group via a hollow shaft carrying the discs. Valve plate 32 has a port 41 above the liquid level (Fig. 3, not shown) to draw drying air through the filter cake and at least one port 44 through which suction is applied to immersed sectors, and port 44 is provided with a valve 45 to vary the degree of suction. As shown valve 45 is a radially movable rod intersecting port 44. An alternative valve would allow a variable amount of air to leak into port 44 from the plate periphery, or valve 45 may be replaced by a rotatable, slotted valve stem. Plate 32 also has means 42, 43 whereby compressed air blows dried filter cake from successive sectors, and scrapers may also be provided. Means 42, 43 comprises a port through plate 32 with a tube 43 extending radially into it and closing the rear side of the port. Plate 32 and housing (31) may be of polyurethane or rigid PVC while plate (33) is steel, this combination having a self-sealing effect. Arrangements wherein plates 32 and (33) are both polyurethane or where plate (33) is polyurethane and plate 32 metal are described as less effective. When worn on one side, plate 32 may be transferred to a similar rotary valve at the other end of the shaft, where its other side will engage a wear plate, tube 43 being then reversed. Figs. 1, 2 (not shown) illustrate a prior art valve.