Efficient double-disc accelerator for continuous-feed centrifuges

Analysis of the hub-type feed accelerator commonly used in decanter centrifuges reveals serious deficiencies. It delivers to the surface of the pool a tangential speed far below the value of ωR, with a consequent loss of G-level and separation effectiveness. Although the G-level corresponding to the rotation speed is ultimately reached, this occurs by an undesirable ‘churning’ action of the conveyor that causes re-suspension and mechanical wear on the conveyor face. Moreover, the feed exiting the accelerator plunges into the pool with a high radial speed and in a circumferentially non-uniform manner. A novel, more effective accelerator is described here. This has vanes situated between parallel discs whose faces are normal to the axis of the machine. The vanes are forward-curved, and thus produce overspeeding. Downstream of the vanes is a conical smoothener, which smears out the jets from the vanes into a nearly uniform conical sheet. Model tests in the laboratory, using water, were used to develop the improved technology, which is equally adaptable to solid-bowl and screen-bowl decanters and also to pusher centrifuges. Many tests in the field, on both decanters and pushers, have verified that the new technology produces significant improvements in capacity and performance.