Abstract: Centrifuge (FIG. 1) having an insert composed of lower portion 9a and upper portion 9b. The insert portions have helical passageways, respectively, 24, 26, for circulation of a heat exchange fluid for temperature control of the separated solids in solids chamber 8. A rib 31 joins the insert portions and has a passageway 25 for transfer of the fluid from the helical passage of the lower portion 9a to the helical passageway of the upper portion 9b, and a passageway 27 for discharge of the fluid.

Abstract: A centrifuge constructed for the intermittent discharge of sludge having a main piston valve 3 for opening and closing of sludge discharge passageways 4, is provided with an auxiliary piston valve 9 mounted on the main piston valve 3 and having an opening chamber 11 and closing chamber 12, supplied with control fluids, so that the operation of auxiliary piston valve 9 is cumulative to the operation of the main piston valve 3 on both opening and closing of the main piston valve. The auxiliary piston valve 9 is mounted 10, 10a on the main piston valve 3 so that the auxiliary piston valve can shift on the main piston valve 3 to open and close dumping passageways 19 provided for emptying of the control chamber 8 of the main piston valve 3.

Abstract: Centrifuge with a drum having an insert lining spaced from and supported on the drum wall for flow of a heat exchange medium through the passage between the drum and insert. The drum is jacketed by a stationary frame member outfitted with heat exchange means, and the outlet from the passage in the drum communicates with the passage provided by the jacket. After flowing down the jacket, the heat exchange medium is pumped back to the passage in the drum.