GB1101437A - Improvements in the separation of solids and liquids - Google Patents

Abstract

1,101,437. Gravity - separation apparatus. DORR-OLIVER Inc. 5 Oct., 1965 [16 Nov., 1964], No. 46501/64. Heading B1D. Equipment for the separation of finelydivided floc-forming solid from a liquid comprises a clarifier 2 with a central flocculation well 1 extending downwards from the top of the tank to end at some distance above the tank bottom, the flocculation well having: at least one internal annular raceway (two being shown at 3, 4) and associated inlets 5, 6 through which the feed can be passed tangentially into the well to flow around the raceways and impart a rotary movement to the feed within it; and internal baffle means 9 positioned at an angle to the rotary flow set up so as to diminish the overall speed of rotation and create eddies in the well to promote flocculation. Preferably the baffle means are twisted metallic ribbons; they may be arranged vertically, as shown, or horizontally on a framework of triangular (horizontal) crosssection, Fig. 6, (not shown). The framework may be secured to a central drive tube 7 to rotate with scrapers also secured to the tube 7. The stilling chamber 12 may be fed by a supply tube extending up from below, and the flocculation well may be supported from below, in which cases the scraper blades are formed in two sections, Fig. 3 (not shown). Alternatively the inlets are formed at the ends of a hollow truss which is fed from a central rising tube, the ribbon baffles extending downwardly from the truss. The truss may rotate with the central drive tube, Fig. 4 (not shown), or be fixed. In the latter case it may assist in supporting the flocculation well, Fig. 5, (not shown). In all cases where the baffle means rotate, their framework preferably has mounted on it scraper blades for maintaining the annular raceways free of silt, as shown in the Figure.