Centrifugal particles - elut ration in front of the direction and process for their use

摘要

1455203 Centrifugal classifiers UNITED STATES ENERGY RESEARCH & DEVELOPMENT ADMINISTRATION 16 May 1974 [6 June 1973] 21711/74 Heading B2P A method of classifying particles suspended in a liquid into two portions having different settling velocities in the suspending liquid comprises the steps of: continuously introducing a sample comprising the particles and suspending liquid into an enclosed rotating right toroidal cavity at a point intermediate the centrifugal and centripetal sides of the cavity; flowing suspending liquid from adjacent the centrifugal side of the cavity towards its centripetal side at a velocity which is intermediate the settling velocities of the two portions of particles, whereby the faster settling portion of particles moves in the centrifugal direction and the slower settling portion moves in the centripetal direction along with the flowing liquid; removing the faster settling particles and suspending liquid from adjacent the centrifugal side of the cavity and removing the slower settling particles and suspending liquid from adjacent the centripetal side of the cavity. As shown in Fig. 1, the rotor of an elutriator has an enclosed toroidal cavity 6 into which open conduit means 7 for suspending liquid, conduit means 8 for removal of slower settling particles and suspending particles, conduit means 10 for introducing a sample of particles suspended in liquid and conduit means 9 for removal of the faster settling particles and suspending liquid. The conduit means may each consist of equally spaced pipe-like passages or of a disc-shaped cavity extending from the rotor housing exterior. Baffles 2, 4 pervious to suspending liquid and particles are located in the cavity to provide uniform flow therethrough and may be in the form of wire mesh, perforated sheet, porous PTFE or of a packed bed of beads. The rotor may consist of peripherally bolted, vertically stacked plates of stainless steel which may be coated with PTFE. In a modification, Fig. 2, the baffle 2' extends only partially across the cavity and a partition 13 extends between the top of the baffle and the centrifugal side of the cavity to provide a flow path for suspending liquid flowing from the conduit means 7 through the baffle 2'. The conduit means 9' in this case is located nearer the centrifugal side of the cavity.