Method and apparatus for continuously separating a more dense fraction from a less dense fraction of a pulp material

摘要

A method and centrifugal separator apparatus for separating more dense particles from less dense particles contained in a slurry. The separator apparatus receives slurry into a rotor assembly which includes a bowl open upwardly and a surrounding hutch chamber. The bowl has a lower impermeable portion coupled to a drive shaft for rotating the rotor assembly, an upper impermeable portion connected to the lower portion, and a frusto-conical screen. The frusto-conical screen forms the inner wall of the hutch chamber and discharge outlets are provided in the periphery of the hutch chamber. An annular fluid inlet connected to the hutch chamber supplies elutriation liquid continuously to the interior of the hutch chamber, and a plurality of pulse blocks supply intermittent pulses of liquid to the hutch chamber. A dam is formed at the top of the screen. In operation, slurry is supplied to the lower portion of the bowl and forms a bed on the screen. A continuous flow of liquid is supplied axially inwardly from the hutch chamber through the screen and slurry bed. Liquid is also lightly pulsed from the hutch chamber axially inwardly through the screen and slurry bed. Under centrifugal, gravitational and liquid flow forces the denser particles migrate toward and through the screen and lighter particles migrate inwardly toward the axis of rotation. The denser particles pass through the screen into the hutch chamber and are collected on exiting from the discharge outlets. The lighter particles are carried over the dam and are collected separately.