| 摘要 |
1,184,119. Travelling-band suction filters. BOWSER, Inc. 26 Sept., 1967 [12 Dec., 1966], No. 43740/67. Heading BID. In a filter of the kind having a band 20 travelling over apertures 50 in a suction box 28 immersed in a tank 10 containing liquid to be filtered, the band 20 has its edges (52a, Fig. 4) magnetically attracted to the surface of the suction box 28 in order to reduce leakage of liquid therebetween. As described, suction is applied by pump 30; when the vacuum inside box 28 is high (owing to clogging of filter band 20), switch 80 senses this and operates valve 82 to short out the vacuum line; this causes pressure to use, and at a predetermined level sensed by switch 81, circuit 83 is energised to drive band 20 a predetermined distance, whereupon high vacuum is restored to re-commence filtering. The band 20 may be cleaned by steam (73), air, vacuum (75) and a rotary wire brush (72), Figs. 8, 9 (not shown). Alternatively, it may comprise an expendable medium 39 carried by an endless belt 52, filtrate being applied at 40 (Fig. 1) to seal the band, 39, 52 against the surface 45 of suction box 28. The edges are sealed by the attraction of magnetic elements 52a, 63, Fig. 4. The rollers 24, 25 on which the band moves may be grooved at (66), (Fig. 6, not shown) in order to ensure vacuum application at the band edges. The suction apertures 50 are provided by slots transverse to the corrugations of an expanded metal sheet (Fig. 5, not shown). |
