Patent GB-637790-A (GB)
Title: Improvements in or relating to filtration apparatus
IPC: B01D33/06
Filed: 1946-07-04
Abstract: 637,790. Filters. KEENE, E. W. W. July 4,1946, No. 20000. [Class 46] In a suction filter of the rotary drum type having a heat exchange element adjacent to the filtering area, the heat exchange element is disposed on the suction side of the filtering area. As applied to a dual surface drum composed of a plurality of individual filter leaves the element comprises a tubular frame 12, Figs. 1 and 2, held between end frames 11a by fish plates 13. Inlet 12a and outlet 12b are fitted with hollow studs 15, Fig. 4, through which a heating medium is supplied and withdrawn from radial tubes fitted to a trunnion shaft connected to an automatic distributing valvehead (not shown) similar to the suction valve at the opposite end of the drum. Filtrate outlets-16 are provided. The leaf surfaces comprise metal sheets 19, which may be perforated, welded to at least the outer tubes of the frame 12 and turned under rods 20, and overlapping filter cloths 21 held at their edges by the turned-under edges of the sheets 19, (which are actually very close together). Vacuum sealing is provided by wire beading 17 and packing 18 round the end of each leaf, and by asbestos strands 39, and filter cake 40 building up during the process, between adjacent leaves. An outer surface thickness regulator for the cake comprises a wire 23, Fig. 4, carried between carriages 22 (one not shown) having flanged wheels 25 guided by rails 26 at each end of a leaf, the carriages swinging by arms 27 about a shaft 29. Counterweights 30 are provided. An inner thickness regulator 32 on a frame 34, 35, supported from the open end of the drum by an arm 36, is adjustable by locknuts 33b, while the arm 36 itself is carried by the shaft 29 and angularly adjustable thereon by a clamping screw 37. As each leaf passes in turn between regulators 23 and 32 the cakes on each side are rendered parallel with the leaf and with each other. According to the Provisional Specification the filtering elements may be of disc or any other shape or form. The heat exchange means may be heated electrically by resistance elements contained therein ; they may comprise a plurality of units, each readily removable for cleaning, renewal or repair. A casing with louvres or other air-control means may be provided to enclose the cake-forming surfaces, and heated or cooled air, which may also be dried, circulated through it. Pressure devices for ironing out cracks in the cake, and means for washing it in a free zone, may be provided. Screw or other conveying means for cake removal may be jacketed for temperature control and may be in an enclosure under reduced pressure. Deflector blades supporting doctors may be heated or cooled by being formed integrally with or being connected to heat exchange means. The filter tank may be jacketed and/or the tank agitator may be of hollow construction for circulation of a heat exchange medium. Shaft and other bearings may be jacketed for cooling medium. Flue gas may be the heating medium. The filter cake may be reinforced by a belt of spiral woven wire, wire netting, endless strings or latex, coated string netting, or a coarse mesh belt of glass, silk, or plastic material may be provided to effect a scraperless discharge. The cake may be removed by a beater or the like. When the filtering elements rotate the heat exchange means is preferably stationary 'and may be supported on a framework surrounding the rotary spindle or hollow shaft. Specification 519,689 is referred to in the Provisional Specification.