Abstract: A centrifugal jig of the type in which a feed slurry is introduced into a container rotating about a vertical axis in a region radially bounded by a screen. The screen is preferably substantially parabolic in shape. Ragging is provided on the screen's inner surface and water is provided in the hutch region on the opposite side of the screen. The water in the hutch region is pulsed repetitiously to dilate the ragging and pulsion of the hutch water is achieved at an interface such as a diaphragm interface or an air/water interface. The interface is positioned substantially wholly beyond the projected free surface of the feed material.

Abstract: A lifting yoke for containers consists of a central beam (1) and two coaxial extending beams (2, 3) guided for reciprocating movements by the central beam and capable of telescoping one into the other. A guide tube (4) arranged coaxially inside the extending beams is able to connect them together when they are extended one from the other and to guide one of the beams into the other when they are telescoped one into the other. The telescoping mechanism (5) for the lifting yoke consists of a hydraulic cylinder (9) with driving wheels (10), two pulleys (11, 12), a cable (13) running over the driving wheels and the pulleys, and protruding rods (14, 15) attached to the cable for operating the extending beams (2, 3).