GB1252893A - - Google Patents

Abstract

1,252,893. Centrifugal strainers. STORKWERKSPOOR-SUGAR N.V. 2 Dec., 1968 [2 Dec., 1967], No. 57131/68. Heading BID. A centrifugal strainer for separating solid material from liquids comprises a frusto-conical drum 4 having an inner filter wall 5, a hollow body 16 to which is attached at least one scraper 23 arranged to operate over substantially the entire height of the inner surface of wall 5, the drum 4 and the body 16 being arranged to rotate, on shafts I and 12 respectively, at slightly different speeds in the same direction; the axis of rotation making an angle α with the inner surface of wall 5, and the scraper having a cutting edge to dislodge solid filter cake from the inner surface of wall 5 on to inwardly facing. porous scraper-base 24. The angle between scraper-base 24 and the axis of rotation is also α. There. are preferably two diametrically disposed scrapers on body 16. The mixture to be filtered is fed through channel 38 to the portion 37 of. body 16, and flows through volute 18, chambers 19 and slots 20 to the filter wall 5. As the chambers 19 move slowly with respect to wall 5, the mixture is deposited thereon in the form of a layer. The liquid passes through the rotating filter wall 5, and then flows through openings 7 in drum 4 into channel 9 which has an outlet 11. The filter cake is lifted off the wall 5 to the base 24 by the scraper 23 situated diametrically opposite. A gas, e.g. air, is fed through hose 30 to chamber 28, flows through outlet 27 and passes through porous base 24. The dislodged solid slides down the base 24, and passes through an opening in the base plate 17 to discharge funnel 34. While on the filter wall, the filter cake may be washed with liquid distributed from sprays secured to body 16. The angle α is so selected for the particular solid material being filtered that the cake just continues to remain on the filter wall during the centrifuging process.