Multi-tray clarification

摘要

564,355. Clarifying liquids. TRIGGS, W. W. (Dorr Co., Inc.). Dec. 8, 1942, No. 17460. [Class 46] In the clarification of liquids, particularly sugar juice, in a multi-tray clarifier in which the liquid is passed into each of a plurality of superposed chambers, clarified liquid is withdrawn from each chamber and a preliminary sedimentation is effected in a plurality of the chambers, the solids separated in the latter pass into a plurality of other chambers having mechanical thickening means therein, each thickening chamber receiving the solids from at least one of the preliminary sedimentation chambers. In the form shown in Fig. 2, liquid passes from a tangential. inlet 30 through a flocculating chamber A and inlets 31 into a rotary tube 22, driven by a motor 19, thence through outlet openings 36 and outlet tubes 39 into preliminary sedimentation chambers B, D and thickening chambers C, E, respectively, the clarified liquid passing through pipes 56 and a regulating overflow box 57 to an outlet 58. The tube 22 carries mud rakes 23 in each chamber, arms 25 supporting flocculation blades 26 in the chamber A, scraper arms 45<1> in a inud trough 41 in the chamber C and scraper blades 45 in the conical outlet 46 of the chamber E. Thickening blades 27 extend upwards from the rakes 23 in the chambers C, E. A mud seal is formed between the chambers A, B. by an upturned flange 34 on the tube 22 co-operating with a fixed flange 35 and a mud-sealed overflow from the chamber C to the chamber D is provided by extending the inner wall 42 of the trough 41 into a hood 43. Separated solids pass from the chambers B, D to the chambers C, E respectively through central passages formed by fixed flanges 35 fitting in cylindrical flanges 38 carried by the tubes 39. The solids are withdrawn through pipes 44, 47 from the chambers C, E by a pump 50 having outlets 55 discharging into a launder 14 having a discharge pipe 59. Scum rising into a chamber 13 overflows a weir 15 into. the launder. In the form shown in Fig. 4, solids pass from preliminary sedimentation chambers B, CA, D through a thickening chamber EA to a thickening chamber E, from which they are removed. The lower end of the rotary tube 22A is closed except for a tubular extension 60, which leads to the outlet- 46 and carries the scrapers 45. The connections between the chambers A, B,-Figs. 2 and 4, may be interchanged.