Abstract: A solid or screen bowl decanting-type centrifuge comprising: a rotatable bowl; a helical scroll conveyor which rotates coaxially within the bowl at a different rotational speed, the helical scroll comprising a hub carrying a plurality of flights whose radially outer edges lie close to an inner wall of the bowl such that, in use, solids are scrolled by the conveyer to solids discharge ports at one end of the bowl, with separated liquid being discharged from liquids discharge ports at the opposite end of the bowl. The conveyor hub carries a plurality of nozzles in a wash zone for supplying wash fluid to solids being scrolled by the conveyer towards the solids discharge ports. The conveyor hub also carries a blade in the region of the nozzles and intermediate adjacent flights of the conveyor for directing fluid droplets from the nozzles over said solids.

Abstract: A solid or screen bowl decanting-type centrifuge comprising: a rotatable bowl; a helical scroll conveyor which rotates coaxially within the bowl at a different rotational speed, the helical scroll comprising a hub carrying a plurality of flights whose radially outer edges lie close to an inner wall of the bowl such that, in use, solids are scrolled by the conveyer to solids discharge ports at one end of the bowl, with separated liquid being discharged from liquids discharge ports at the opposite end of the bowl. The conveyor hub carries a plurality of nozzles in a wash zone for supplying wash fluid to solids being scrolled by the conveyer towards the solids discharge ports. The conveyor hub also carries a blade in the region of the nozzles and intermediate adjacent flights of the conveyor for directing fluid droplets from the nozzles over said solids.

Abstract: An apparatus which performs solids particles separation from a liquids/solids slurry, and subsequent drying of such solids particles, within a single enclosure. Further processing functions, such as reslurry washing, plug washing, crystal growth and other reactions, can also be carried out within that single enclosure.

Abstract: A centrifuge basket shell formed by winding fiber-reinforced resin tape in a helical pattern over a thin shell plate which contains a plurality of holes for the passage of liquid therethrough, perforations being formed in the helix pattern of the wound tape by means of respective hollow ferrules connected rigidly to a cylindrical part of the shell plate, so as to enable liquid which passes through said holes in the shell plate to pass also through the helices of wound tape without increasing the stresses induced therein by rotation.

Abstract: A centrifuge, for example a decanter type centrifuge, comprises a bowl (10) rotatable about a longitudinal rotational axis (Y), an inlet (14) for feeding into the bowl a slurry to be separated, and a helical scroll conveyor (12) rotatably mounted about the rotational axis and adapted to be rotated within the bowl at a different speed from that of the bowl in order to scroll particles adjacent to the bowl wall to a solids discharge end of the bowl. The decanter further comprises a plurality of walls (23) at least partly submerged in the centrate and defining passages therebetween. By providing a plurality of passages, through which the centrate to be clarified can travel, particles (e.g. solids) to be separated from the centrate have a short distance to travel under centrifugal force before entering the boundary layer at the walls of the passages. This enables more of the fine particles in the centrate to be separated out.

Abstract: A method and apparatus for testing, in situ, for imperfections in an inert coating of a moving metal component of an apparatus (e.g. a metal basket of a centrifuge) involves covering the inert coating with an electrically conductive liquid, applying an electrical voltage across the inert coating while the apparatus is operational, monitoring the current or applied voltage, and utilizing the measured current or voltge to provide an indication of the condition of the inert coating. If the coating is defective, the conductive liquid will find its way into any flaws or imperfections, thereby providing a path of lower electrical resistance.

Abstract: A method of separating solid particles from the liquid constituent of a slurry, containing solids having a "wide" particle size distribution, that is, a size distribution wherein the equivalent diameter of particles in the slurry ranges between at least 15 microns and 150 microns. The method uses a screen bowl centrifuge and comprises: (a) establishing a bed of solids on the screen section of the centrifuge whose maximum radial thickness is greater than 15 times the mean particle equivalent diameter of said solids in the slurry; (b) operating the scroll of the centrifuge at a speed within the range of 0.5 to 10% of the bowl speed; and (c) returning at least a portion of the solids contaminated centrate from the centrifuge to the interior of the screen section of the bowl so as to deposit the centrate on the solids passing over the screen section at or adjacent a region of maximum solids thickness.

Abstract: A decanting type centrifuge having a main bowl which is adapted to be rotated about its longitudinal axis and which contains a helical scroll conveyor which is arranged to rotate about the main bowl axis at a slightly different speed to the main bowl for scrolling separated solids to a solids discharge end of the bowl. The centrifuge includes a means which acts to isolate a gas volume radially inwardly of the inner liquid surface within the bowl and also a passage arrangement which enables gas to be extracted continuously from the isolated gas volume to a location external to the main bowl.

Abstract: In a gas-tight sealing device for rotary gas-liquid contacting apparatus, a liquid channel takes excess sealing liquid away from the seal to reduce viscous drag.

Abstract: A solid bowl decanter centrifuge of the scroll discharge type comprises a solid bowl which rotates at a first speed, and a scroll conveyor which is rotated within the bowl at a second, slightly different speed for conveying separated solids to a solids discharge end of the bowl. The suspension to be centrifuges, substantially unmixed with a flocculant, is introduced by a stationary feed pipe into a feed compartment which is a radial passage in the conveyor. The feed compartment provides high turbulence and shear forces which mix and expel the suspension and flocculant into the bowl before flocs have formed.

Abstract: A washer or hydro-extractor comprising a cylindrical basket adapted to be rotated about its longitudinal axis for liquid extracting operations on wet material placed therein. A plurality of rigid flaps within the basket are selectably pivotable about respective axes extending longitudinally of the basket. The flaps normally lie substantially flat against the inner cylindrical surface of the basket. A respective cam follower is rigidly coupled to each flap via a respective crank arm. In order to selectably pivot the flaps for stripping caked material from the inner surface of the basket, a stripper cam is selectably displaceable into a position in which it engages the cam followers of those flaps which, at any instant during stripping, lie in what is, at that time, the upper part of the basket, whereby the latter flaps are pivoted from their normal positions for effecting stripping.

Abstract: A solid bowl decanter centrifuge comprising a solid, generally cylindrical bowl having a liquids outlet at one end and a solids outlet at the other end. A drive for rotating the bowl at a first speed. Inlet pipework for introducing influent to the interior of the bowl and a feed valve in the inlet pipework for controlling the rate of flow of influent therethrough. A scroll conveyor mounted for rotation within the bowl at a second speed. A hydraulic motor whose body is connected to the bowl and whose output shaft is connected to the scroll conveyor whereby the motor speed determines the differential speed of the conveyor relative to the bowl. The hydraulic motor has a hydraulic drive system which includes a pump for supplying hydraulic fluid to the motor.

Abstract: A pendulum suspended, hydraulically driven basket centrifuge comprises a centrifuge basket adapted to be rotated about a vertical axis by a hydraulic motor. The basket is mounted on the upper end of a vertically extending main spindle which is journalled within a cylindrical casing by means of two bearing assemblies disposed at upper and lower portions on the spindle, respectively. The hydraulic motor, the casing, the bearing assemblies and the main spindle are constructed as a cartridge unit which can be removed from the basket as a complete sub-assembly.

Abstract: The invention concerns scroll discharge decanter centrifuges of the type in which the interior of the centrifuge is to be kept sealed from the atmosphere and which comprise a stationary assembly which includes an outer casing, a rotary assembly which includes a solid bowl which is adapted to be rotated within the stationary casing at a first speed and a scroll conveyor which is rotatable within the bowl at a second, slightly different speed. A plurality of sealing devices are arranged to be effective between the rotary assembly and the stationary assembly. Each sealing device comprises a first ring fixed relative to the stationary assembly and a second, coaxial ring which is adapted to rotate with the rotary assembly. That surface of the first ring which faces the second ring contains a plurality of gas jet nozzles by way of which pressurized gas can be supplied to an annular clearance gap between the first and second rings.

Abstract: In accordance with the present invention there is provided a washer or fluid extractor comprising a cylindrical basket adapted to be rotated about its longitudinal axis for fluid extracting operations on material placed therein, at least one rope, or other elongate flexible member, extending between a first location in the region of the basket mouth and a second location in the central region of the basket base, the rope tension being selectively adjustable such that, when centrifuging, the rope can take up the profile of the basket interior but, when centrifuging is terminated, the rope can be tightened so that it is displaced inwardly of the cylindrical wall of the basket whereby to dislodge centrifuged material therefrom, means being provided for preventing entanglement of material in the basket with the rope.