Decanter centrifuge having an offset conveyor flight to aid rinsing
AssigneeTetra Laval Holdings & Finance S.A.
InventorJohn W. Caldwell
Life of this patent
Estimating the term…
Abstract
A liquid-solids separator, or centrifuge, of the type having a screw conveyor is provided with a series of offset conveyor flights. A spacer is positioned within the offset of the conveyor flights to form a channel therein. Rinse liquid is introduced into the channel through the central hub of the conveyor. The channel directs the rinse liquid into the heavy phase cake. An opening may be provided at various radial distances for varying the position of introduction of the rinse liquid from the channel. The amount of rinse liquid introduced through various channels formed by the series of offset conveyor flights may also be varied.
Claims20
In a centrifuge of the type having a rotatable screw conveyor therein, the screw conveyor comprising:
- a central longitudinally-extending hub;
- a conveyor flight having at least two conveyor flight portions which form a spiral along at least a portion of the axial length of the central hub, the conveyor flight extending outward from the central hub to a distal end, at least one of the conveyor flight portions being axially offset with respect to and overlapping a portion of another conveyor flight portion;
- spacer means positioned within the offset between two of the conveyor flight portions, the spacer means and the offset of the conveyor flight portions forming a channel;
- and
- means for introducing a rinse liquid into the channel from the conveyor hub.
A rotating separator for separating a heavy phase/solids material from a liquid within a mixture, the separator having a screw conveyor with a helical conveyor flight to transport the heavy phase/solids, and a bowl surrounding the conveyor which rotates at a speed different from the conveyor, the separator comprising:
- at least two conveyor flight portions forming the helical conveyor flight, one of the conveyor flight portions being axially offset from and overlapping a portion of another conveyor flight portion, and a spacer extending between the offset portions, and channel means formed by the offset of the two conveyor flight portions, the channel means adapted to direct a rinse liquid into the bowl during rotation thereof, the channel means directing the rinse liquid into the separated heavy phase/solids while at the same time mixing the heavy phase/solids and the rinse liquid at the point of introduction.
A decanter centrifuge comprising:
- a conveyor rotated about a central longitudinally-extending axis;
- and
- a bowl coaxially mounted with the conveyor and rotated at a differential speed with respect to the conveyor, the bowl having a cylindrical portion and a frusto-conical portion;
- the conveyor including
- a central longitudinally-extending hub,
- a conveyor flight forming a spiral along the central hub along at least a portion of the length of the hub, the conveyor flight extending radially outward from the central hub to a distal end positioned adjacent an inside surface of the bowl, and at least a portion of the conveyor flight overlapping and being axially offset with respect to an adjacent portion,
- a spacer positioned within and extending across the axial offset between the adjacent conveyor flight portions, the spacer and the offset of the conveyor flight portions forming a channel, the channel extending radially outward from the hub toward the distal end of the conveyor flight and being open in the direction of rotation of the conveyor, and
- an opening formed within the conveyor hub, the opening communicating with the channel and adapted to introduce a rinse liquid from the conveyor hub into the channel.
A decanter centrifuge comprising:
- a conveyor rotated about a central longitudinally-extending axis;
- a bowl coaxially mounted with the conveyor and rotated at a differential speed with respect to the conveyor, the bowl having a cylindrical portion, a light phase discharge, and a heavy phase discharge, the heavy phase discharge being at one end of the bowl;
- and
- means for introducing a feed liquid into the bowl from the conveyor;
- the conveyor comprising
- a central longitudinally extending hub,
- a conveyor flight forming a spiral along the central hub, at least a portion of the conveyor flight extending radially outward from the central hub to a distal end positioned adjacent an inside surface of the bowl, the conveyor flight having a forward surface and a rear surface, the forward surface generally facing in the direction of the heavy phase discharge, at least a portion of the conveyor flight overlapping and being axially offset along the hub with respect to an adjacent portion of the conveyor flight, the axially rearward conveyor flight portion spiraling along the hub from the offset in the direction of the heavy phase discharge,
- a spacer positioned within the offset between the adjacent conveyor flight portions, the spacer attached to the rear surface of the axially forward conveyor flight portion and to the forward surface of the axially rearward portion, the spacer and the offset of the conveyor flight portions forming three sides of a channel, the channel extending radially outwardly from the conveyor hub toward the distal end of the conveyor flight and being open in the direction of rotation of the conveyor, the channel adapted to direct rinse liquid from the introducing means, radially outward toward the distal end of the conveyor flight, and
- wherein a segment of the axially forward offset conveyor flight portion radially inward of the distal end projects into the channel to direct rinse liquid out of the channel and onto the axially forward portion of the conveyor flight.
Dependencies are inferred from the claim text.