GB1283883A - Centrifuge - Google Patents

Abstract

1283883 Centrifugal separator PENNWALT CORP 19 April 1971 [30 Jan 1970] 20347/71 Heading B2P A centrifuge for separating solids, a heavy liquid and a light liquid from a liquids-solids mixture comprises an elongated rotatable bowl 12 having a portion 22 tapering towards one end of the bowl at which a solids discharge opening 26 is disposed, the other end of the bowl having a radially outer group of openings 30 for discharge of the heavy liquid, and a radially inner group of openings 32 for discharge of the light liquid; a screw conveyor 18 mounted for coaxial rotation in the bowl and including a hub defining an annular separating chamber 40 with the bowl; an inlet 38 for introducing the mixture into the chamber 40; and a member 42 or 56 whose position is adjustable radially of the centrifuge, either by removal or replacement by a like member of different radial size or by mechanical adjustment, in order to permit variation of the position of the line of separation (denoted E- line in Fig. 2) between the heavy and light liquids. The mixture is introduced into a feed chamber 34 in the screw conveyor 18 through a pipe 36 and passes therefrom into the chamber 40 through radial passages 38 in the conveyor hub. A ring dam 42, available in various sizes, is removably mounted adjacent the openings 32 and acts as a weir over which the light liquid flows on being discharged through the openings 32. A ring 44 mounted adjacent the ring dam 42 partially extends over the heavy liquid discharge openings 30 and prevents the discharge therethrough of any emulsion which may form between the two liquids. Ribs 46 mounted to the face of ring 44 prevent relative rotation between the separated liquids and the bowl prior to discharge of the liquids. A screen member 48 may be removably mounted to the face of the ribs 46 to reduce turbulence of the liquids being discharged. A vane member 68 extending between adjacent flights 20 of the conveyor 18 at the solids discharge end of the separation chamber 40 acts as a rotating dam which allows only heavy liquid to flow to the converging portion of chamber 40. A scraper 70 mounted on the screw conveyor flight 20 adjacent the liquids discharge end 28 of the bowl removes solids which accumulate on the inner surface of the bowl adjacent the openings 30. An annular cup-shaped member 50 mounted on the exterior side of the bowl end 28 has a flange portion 53 which defines with the outer surface of the bowl 12 an annular zone 55 with which the light liquid discharge openings 30 are in communication via passageways 33. A base portion 51 of the member 50 has a radially extending rim 52 which defines with the bowl end 28 a channel 54 into which the heavy liquid discharge openings 30 terminate. Mounted in the channel 54 is a skimmer tube 56 by means of which the heavy liquid is discharged from the channel 54 into an annular space 67 between the bowl and a cover 14. The depth of the skimmer tube 56 may be adjusted in the channel 54 by means of a mechanism, Fig. 5 (not shown) comprising a crank (82), a threaded bolt (84), a slide member (89), a lever rod (85) and an eccentrically mounted skimmer ring 80 to which the tube 56 is welded. The space 67 is sealed from a space 65 which receives the light liquid by means of a labyrinth seal 60-62, 61-63.