Abstract: An apparatus for the centrifugal separation of a solid-liquid mixture including an elongate centrifuge drum rotatable about a central axis, a coaxially located conveyor worm within the drum having worm helix flights on a worm drum therein, an opening for the discharge of a light fraction and an opening for the discharge of a heavy fraction, the opening for the discharge of the light fraction located in a radius from the drum axis less than the radius of the worm drum and the opening for the heavy fraction being located at a radius relative to the axis of the drum less than the radius of the worm drum.

Abstract: When a screw-conveyor centrifuge is turned off and its rotation speed diminishes to the point where the centrifugal force is smaller than the force of gravitation, the liquid ring formed inside the centrifuge bowl under the centrifugal force collapses, and a detrimental discharge of liquid takes place at the solids discharge of the centrifuge. In accordance with the method of this invention, the rotation speed of the centrifuge bowl (2) and/or of the screw conveyor (4) is briefly abruptly changed immediately before this critical rotation speed is reached, so that the liquid ring is caused to spiral toward the liquid discharge openings (5) at the other end of the centrifuge (1) by the screw helices (3) of the screw conveyor (4).

Abstract: A method of operating a drum centrifuge having a foraminous drum rotatable about an axis it is centered on comprises first filling a charge of a suspension into the drum while rotating it about its axis so that the charge forms an annular stratified body having an inner surface and the liquid phase of the body passes radially outward and leaves behind the solid phase as a filter cake and then refilling at least one additional charge of a suspension into the drum onto the filter cake while rotating the drum as in the preceding filling step to add the solid phase of the additional charge to the cake already in the drum. Then at least periodically the radial position of the inner surface of the body in the drum is detected and the dry point when the liquid phase has substantially passed radially out of the drum is ascertained to generate outputs corresponding to the detected radial positions and the times same are detected.

Abstract: A method of operating a particle-treating apparatus having a hollow foraminous drum centered on and rotatable about an upright axis comprises the steps of feeding particles into the upper portion of the interior of the drum, rotating the drum about the axis at a speed sufficient to form the particles into an annular body lying on the inner surface of the drum, passing a drying gas radially inward through the drum into the interior thereof and withdrawing the gas axially from the interior to at least partially fluidize the body and dry the particles, and collecting the particles beneath the drum as the body moves off the lower edge thereof. The rate of gas flow through the drum and the rotation rate of the drum are such that the body moves axially down in the interior toward the lower edge of the drum.