| 摘要 |
1,101,696. Centrifugal separators. BIRD MACHINE CO. 15 June, 1966 [17 June 1965], No. 26616/66. Heading B2P. A process, for separating solids suspended in liquid, comprises a primary stage separator 10 and a secondary stage separator including a centrifuge 22 and another separator 18. A major part of the overflow from the primary stage separation may be recirculated for use without separating therefrom a fraction of the solids requiring chemical addition for separation. The suspension is treated in the primary stage separator so that the overflow suspension contains substantially the solids fraction. The primary stage underflow is fed to the centrifuge 22. A major part of the overflow from the primary separator is recirculated for use elsewhere via a line 14. Another portion of the overflow is fed to the other secondary stage separator 18 and a flocculant reagent is added from a tank 24 via a line 26 to cause separation of the solids content from the overflow of the secondary stage separator. The underflow is fed from the secondary separator to the centrifuge. A flocculant reagent is added to the feed to the centrifuge from a tank 27 to cause the solids fraction to separate 'from the effluent of the centrifuge together with the other solids content of the feed. As described, the underflow from the primary stage is heated to 100‹ to 150‹F by a heat exchanger 20 before it is fed to the centrifuge 22. The primary stage separator may be a large settling tank located outdoors and the secondary separator a small settling tank located indoors. Alternative embodiments may include separators other than tanks, e.g. centrifuges. and the centrifuge overflow may be recirculated.
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