Solid bowl centrifuge having a dam edge with an energy recovery device located on the dam edge and at least sections of the dam edge are pivoted toward a rotational direction of the solid bowl centrifuge as viewed from a rotational axis

Abstract

A solid bowl centrifuge has a centrifuge bowl that can be rotated in a rotational direction about a longitudinal axis during operation. An end face of the centrifuge bowl has at least one flow-off opening for the flow-off of clarified material from the centrifuge bowl. A dam edge bounds the flow-off opening in the radially outward direction, and an energy recovery device is located on the dam edge for recovering energy of the clarified material flowing. The dam edge is pivoted toward the rotational direction at least in some sections, as viewed from the longitudinal axis.

Claims

1. A solid bowl centrifuge (10) comprising a centrifuge bowl (12) that can be rotated in a rotational direction (36) about a longitudinal axis (18) during operation, at least one flow-off opening (16) at an end face of the centrifuge bowl (12) for flow-off of clarified material (24) from the centrifuge bowl (12), a dam edge (22, 42), which bounds the flow-off opening (16) in a radially outward direction, and an energy recovery device (28, 52) located on the dam edge (22, 42) for recovering energy of the clarified material (24) flowing off, wherein the dam edge (42) is arranged pivoted toward the rotational direction (36) at least in some sections as viewed from the longitudinal axis (18), such that the dam edge (42) extends at a slant to the longitudinal axis (18), wherein the pivot position of the dam edge (42) toward the rotational direction (36) causes the flow of the clarified material (24) behind the dam edge (22, 42) also to moved initially in the rotational direction (36) and to direct the clarified material (24) strongly toward the energy recovery device (28, 52).

2. The solid bowl centrifuge of claim 1, wherein the at least some sections of the dam edge (42) are arranged pivoted toward the rotational direction (36) at an angle between 2 and 45 at least in some sections.

3. The solid bowl centrifuge of claim 2, wherein all of the dam edge (42) is arranged pivoted toward the rotational direction (36) overall.

4. The solid bowl centrifuge of claim 1, wherein an overflow surface (48) pivoted radially outward for the material (24) flowing off is formed after the dam edge (42) in the flow direction of the material (24) flowing off over the dam edge (42).

5. The solid bowl centrifuge of claim 4, wherein the overflow surface (48) extends along the entire dam edge (42).

6. The solid bowl centrifuge of claim 4, wherein the overflow surface (48) is arranged pivoted radially outward in relation to the longitudinal axis (18) at an angle between 10 and 65.

7. The solid bowl centrifuge of claim 1, wherein the energy recovery device (52) has a deflecting surface (56) that deflects the material (24) flowing off against the rotational direction (36).

8. The solid bowl centrifuge of claim 7, wherein the deflecting surface (56) is arranged axially after the dam edge (42), as viewed in the direction of the longitudinal axis (18).

9. The solid bowl centrifuge of to claim 7, wherein the deflecting surface (56) is arranged exclusively radially outside of the dam edge (42), as viewed in the direction of the longitudinal axis (18).

10. The solid bowl centrifuge of claim 1, wherein the dam edge (42) and the energy recovery device (52) are designed as an assembly that can be jointly adjusted on the centrifuge bowl (12).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a partially cut side view of a centrifuge bowl, comprising a dam plate and an energy recovery device of a solid bowl centrifuge according to the prior art.

(2) FIG. 2 shows section II-II in FIG. 1.

(3) FIG. 3 shows a partially cut side view of a centrifuge bowl, comprising a dam plate and an energy recovery device, of a first embodiment of a solid bowl centrifuge according to the invention.

(4) FIG. 4 shows view IV according to FIG. 3.

(5) FIG. 5 shows section V-V according to FIG. 4.

(6) FIG. 6 shows a partially cut side view of a centrifuge bowl, comprising a dam plate and an energy recovery device, of a second embodiment of a solid bowl centrifuge according to the invention.

(7) FIG. 7 shows view VII according to FIG. 6.

(8) FIG. 8 shows part of a view according to FIG. 7 of a third embodiment of a solid bowl centrifuge according to the invention.

DETAILED DESCRIPTION

(9) In FIGS. 1 and 2, the end wall 14 of a centrifuge bowl 12 of a solid bowl centrifuge 10 is shown. One of several flow-off openings 16 extending axially through the end wall 14, in the direction of a longitudinal axis 18 of the centrifuge bowl 12, is illustrated on the end wall 14. A dam plate 20 is attached to the outside of the end wall 14, in front of the flow-off opening 16, in such a way that the dam plate is stationary but adjustable. The dam plate 20 protrudes in front of the flow-off opening 16, and therefore the dam plate 20 covers the flow-off opening 16 on the outside in the radial outer region of the flow-off opening 16. The dam plate 20 has a dam edge 22 at the edge of the dam plate 20 directed radially inward. This dam edge 22 according to the prior art extends along the end wall 14 and thus transversely to the longitudinal axis 18, or at an angle of 90 to the longitudinal axis 18. The dam edge 22 holds back clarified material 24 in the centrifuge bowl 12, and therefore, during operation of the solid bowl centrifuge 10, this clarified material 24 accumulates there with a pond depth 26 and subsequently flows off over the dam edge 22 largely continuously.

(10) After or downstream of the dam edge 22 in the flow direction of the clarified material 24, there is an energy recovery device 28 according to the prior art on the outside of the dam plate 20. This energy recovery device 28 is designed as a flow-off channel 30, which has a flat bottom surface 32 extending tangentially at the height of the dam edge 22. A deflecting surface 34 extends to the bottom surface 32 perpendicularly as part of the flow-off channel 30. According to the prior art, the deflecting surface 34 extends in an arcuate shape in front of the region of the flow-off opening 16 that is open as viewed in the longitudinal direction. The deflecting surface 34 deflects the clarified material 24, which approaches axially through the flow-off opening 16 at the radial inside and under the dam edge 22 in an inflow direction 38, in a tangential direction into an outflow direction 40. The centrifuge bowl 12 rotates in a rotational direction 36, and the clarified material 24 is deflected by the deflecting surface 34 in such a way that the clarified material 24 exits the energy recovery device 28 tangentially against this rotational direction 36. When the clarified material 24 exits, the clarified material 24 pushes off from the centrifuge bowl 12, whereby the clarified material 24 transfers part of its momentum to the centrifuge bowl 12 and contributes to energy recovery at the centrifuge bowl 12. This pushing off is lessened by the internal liquid friction in the clarified material 24 and in that the centrifuge bowl 12 turns further in the rotational direction 36 at the same time. Thus, the centrifuge bowl 12 partially evades the pushing off.

(11) In FIGS. 3 to 5, an embodiment of a solid bowl centrifuge 10 is illustrated by means of its centrifuge bowl 12, on the dam plate 20 of which a dam edge 42 according to the invention is provided. This dam edge 42 is pivoted by an angle 44 of 10 toward the rotational direction 36 with respect to the longitudinal axis 18 in the total extension or length of the dam edge as a straight section. Thus, the dam edge 42 does not extend in the transverse direction but rather points toward the rotational direction 36 at an angle on the outside.

(12) A flow-off channel 46 according to the invention is located after the dam edge 42 in the flow direction of the clarified material 24. The flow-off channel 46 is designed initially with a flat overflow surface 48 tilted radially outward. The overflow surface 48 is tilted at an angle 50 of 45 from the longitudinal axis 18 of the centrifuge bowl 12 and extends over the entire width of the dam edge 42. The overflow surface 48 is part of an energy recovery device 52 according to the invention and directs the material 24 flowing off over the angled dam edge 42 slightly radially outward and against the rotational direction 36. In the process, this material 24 is accelerated with regard to its flow velocity. Thus, the potential energy of the material 24 is converted into kinetic energy to a certain extent within the energy recovery device 52.

(13) Directly after the overflow surface 48, the flow-off channel 46 of the energy recovery device 52 according to the invention also comprises a flat bottom surface 54, which, however, lies somewhat further radially outside than the dam edge 42. Furthermore, an arcuate deflecting surface 56 is also provided. The material 24 flowing off is conducted toward this deflecting surface 56 slightly against the rotational direction 36 by the overflow surface 48, as explained above, especially in an accelerated manner. Thus, a higher energy input or a strong momentum transfer from the clarified material 24 flowing off to the energy recovery device 52 can occur at the deflecting surface 56. Thus, the deflecting surface 56 can be designed especially small, and it is sufficient if the deflecting surface 56 extends radially inward only to the depth of the dam edge 42. With the deflecting surface 56 that is small in such a way, a relatively small flow resistance on the outside of the centrifuge bowl 12, which rotates at high speed, is achieved for the energy recovery device 52.

(14) FIGS. 6 and 7 show an embodiment of a dam edge 42 that is preferred according to the invention, together with an energy recovery device 52 according to the invention, wherein the dam edge 42 is oriented at angle 44 of 20 to the longitudinal axis 18.

(15) Finally, in FIG. 8, a very similar embodiment is shown, wherein the associated dam plate 20 together with the dam edge 42 according to the invention and the energy recovery device 52 is tilted radially inward at an angle 58 between 5 and 10, preferably of 8, as viewed from the tangential direction against the rotational direction 36.

(16) Finally, it is noted that all features stated in the application documents and in particular in the dependent claims, despite the formal reference made to one or more certain claims, should also be given independent protection individually or in any combination.

LIST OF REFERENCE SIGNS

(17) 10 solid bowl centrifuge 12 centrifuge bowl 14 end wall 16 flow-off opening 18 longitudinal axis of the centrifuge bowl 20 dam plate 22 dam edge according to the prior art 24 clarified material 26 pond depth 28 energy recovery device according to the prior art 30 flow-off channel according to the prior art 32 bottom surface according to the prior art 34 deflecting surface according to the prior art 36 rotational direction 38 inflow direction of the clarified material (axial) 40 outflow direction of the clarified material (tangential) 42 dam edge according to the invention 44 angle of the tilt of the dam edge in relation to the longitudinal axis 46 flow-off channel according to the invention 48 overflow surface according to the invention 50 angle of the tilt of the overflow surface in relation to the longitudinal axis 52 energy recovery device according to the invention 54 bottom surface according to the invention 56 deflecting surface according to the invention 58 angle of the inclination of the bottom surface in relation to the radial direction