Baker Hughes Corporation

Woon-Fong Leung

Ascher H Shapiro

Robert S Yarnell

A centrifuge has a hub and a first bowl section extending about the hub. The first bowl section has a given diameter at a downstream end of a heavy phase transport path along the first bowl section. The centrifuge further comprises a second bowl section having an input end at the downstream end of the first bowl section. The input end of the second bowl section has a diameter which is greater than the diameter of the first bowl section at the downstream end thereof. The input end of the second bowl section is disposed radially outwardly of the first bowl section at the downstream end thereof. A feed accelerator is disposed at the downstream end of the first bowl section, and more particularly between the downstream end of the first bowl section and the input end of the section bowl section, for tangentially accelerating a thickened feed or cake between the downstream end of the first conical bowl section and the input end of the second bowl section. The feed accelerator serves to accelerate, in the direction of rotation (as opposed to radially accelerating), a thickened feed of nominally 40-60% solids moving from the downstream end of the first conical bowl section to the upstream end of the second conical bowl section.

Centrifuge with thickened-feed accelerator between inner and outer bowl sections

A centrifuge includes a conveyor for moving cake along a cake flow path towards a cake discharge opening and further includes a baffle mounted to the conveyor and disposed along the cake flow path. The baffle is provided on an upstream side, facing substantially away from the discharge opening, with a concave profile or surface. This concave profile or surface serves to direct a portion of the cake, which is headed downstream along the cake flow path, into a recirculation or churning path directed partly back towards a pool. The recirculation or churning of the particulate material facilitates an enhanced washing thereof and improves the removal of valuable solutes or undesirable impurities from the cake.

Centrifuge with cake churning

A decanter centrifuge comprises a bowl rotatable about a longitudinal axis, the bowl being provided with a cake discharge opening at one end and a liquid phase discharge opening. The bowl has a cylindrical portion and a beach portion disposed between the cylindrical portion and the cake discharge opening. A beach area is provided on an inner surface of the bowl at the beach portion of the bowl, the beach area including a first section and a second section with the second section located between the first section and the cake discharge opening. The second section of the beach area has a less steep or smaller slope than the first section. A conveyor is at least partially disposed inside the bowl for rotation about the longitudinal axis at an angular speed different from an angular rotational speed of the bowl. The conveyor includes a helical screw disposed inside the bowl for scrolling a deposited solids cake layer along the inner surface of the bowl towards the cake discharge opening. A feed element extends into the bowl and the conveyor for delivering a feed slurry into a pool inside the bowl. A flow control structure is provided in the bowl proximate to the second section of the beach area for impeding a flow of cake along the bowl towards the cake discharge opening.

Decanter centrifuge for producing cake with reduced moisture content and

A feed accelerator system for use in a centrifuge, the system comprising a conveyor hub rotatably mounted within a rotating bowl, the hub including an inside surface and an outside surface. At least one feed slurry passageway is disposed between the inside surface of conveyor hub and the outside surface of the conveyor hub, and at least one helical blade having a plurality of turns is mounted to the outside surface of the conveyor hub. A vane apparatus is associated with the passageway and is disposed between two adjacent turns of the helical blade. The vane apparatus may include an inwardly extending baffle and/or an outwardly extending accelerator vane. Alternatively, a U-shaped channel may be associated with the passageway, the U-shaped channel including a plurality partitions attached to the discharge end of such channel so as to form a plurality of discharge channels and a flow directing and overspeeding vane disposed within each channel, each vane having a different forward discharge angle.

Feed accelerator system including accelerating vane apparatus

Liquid is drained from the cake in the beach section of a centrifuge bowl by providing a dedicated flow path or a series of flow paths from the beach section. The flow path or paths are designed to drain away expressed liquid while maintaining substantially the flow of cake up the beach to the cake discharge opening(s) irrespective of solid throughput. The expressed liquid is guided from the beach section back to the slurry pool in the cylindrical section of the centrifuge bowl. More specifically, one or more liquid guide channels may be provided in the beach area under the surface supporting the cake flow towards the cake discharge end of the centrifuge. The liquid guide channels may be established by providing a porous liner along the beach section of the centrifuge bowl. Preferably, the liner extends down the beach at least to the level of the pool.

Solid bowl centrifuge with beach having dedicated liquid drainage

Decanter centrifuge and associated method for producing cake with

A decanter centrifuge comprises a bowl having a plurality of cake discharge openings at one end and a liquid phase discharge opening. The bowl is rotatable about a longitudinal axis, while the cake discharge openings are disposed in a plane oriented transversely relative to the longitudinal axis. The bowl has a cylindrical portion and a beach portion between the cylindrical portion and the cake discharge openings. A conveyor is disposed at least partially inside the bowl for rotation about the longitudinal axis at an angular speed different from an angular rotational speed of the bowl. The conveyor includes a helical screw disposed inside the bowl for scrolling a deposited solids cake layer along an inner surface of the bowl towards the cake discharge openings. A feed element extends into the bowl and the conveyor for delivering a feed slurry into a pool inside the bowl. Pursuant to the invention, a flow control structure is provided on the bowl at the cake discharge openings for varying a cross-sectional area of the cake discharge openings to selectively impede a flow of cake along the bowl towards the cake discharge openings, thereby obtaining the desired cake dryness.

Decanter centrifuge with discharge opening adjustment control and

A decanter centrifuge comprises a bowl and a worm or screw type conveyor. The bowl is rotatable about a longitudinal axis and has a cake discharge opening at one end and a liquid phase discharge opening. The conveyor includes a conveyor hub having at least a portion disposed inside the bowl for rotation about the longitudinal axis at an angular speed different from an angular rotational speed of the bowl. The conveyor further includes a helical screw or worm attached to the conveyor hub and disposed inside the bowl for scrolling a cake layer along an inner surface of the bowl towards the cake discharge opening. An adjustable component on the hub forms a gap between the hub and the inner surface of the bowl so that the gap has a size adjustable independently of hub rotation speed. The adjustable gap enables an optimization of the moisture content of cake exiting the bowl at the cake discharge opening for a given solids throughput and cake rheology. The adjustable component on the hub takes the form of an annular weir or a baffle plate.

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Sherborn, MA, United States of America

Woon-Fong Leung