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.
ASJC Scopus subject areas
- General Environmental Science
- Filtration and Separation
- Industrial and Manufacturing Engineering