Solid-bowl screw centrifuge having an energy recovery device

Abstract

A solid-bowl screw centrifuge has a centrifuge drum that is rotatable about a longitudinal axis, at least one outlet for discharging clarified material from the centrifuge drum, and an energy recovery device, arranged at the outlet, for recovering energy from the discharged clarified material, when the solid-bowl screw centrifuge is in operation, the centrifuge drum can rotate in a first direction of rotation and in a second direction of rotation opposite to the first direction of rotation. The energy recovery device has a first active surface, via which clarified material can flow out when the centrifuge drum is rotated in the first direction of rotation, and a second active surface, via which clarified material can flow out when the centrifuge drum is rotated in the second direction of rotation.

Claims

1. A solid-bowl screw centrifuge comprising: a centrifuge drum that is selectively rotatable about a longitudinal axis in either of a first direction of rotation (16) and a second direction of rotation (18) that is opposite to the first direction of rotation (16), at least one outlet (14) for discharging clarified material from the centrifuge drum, and an energy recovery device (10), arranged at the outlet (14)the energy recovery device (10) being movable to a first position (34) when the centrifuge drum is rotated in the first direction of rotation (16) and to a second position (36) when the centrifuge drum is rotated in the second direction of rotation (18), the energy recovery device (10) having a first active surface (20) configured to discharge the clarified material to the outlet (14) when the energy recovery device (10) is in the first position (34) and the centrifuge drum is rotated in the first direction of rotation (16), and a second active surface (22) configured to discharge the clarified material to the outlet (14) when the energy recovery device (10) is in the second position (36) and the centrifuge drum is rotated in the second direction of rotation (18), the energy recovery device (10) being inclined at an angle in a range of between +/2 and +/20 with respect to a radial direction (38) of the respective outlet (14) when the energy recovery device (10) is in either of the first position (34) and the second position (36).

2. The solid-bowl screw centrifuge of claim 1, wherein the two active surfaces (20, 22) are formed on a single shell (24).

3. The solid-bowl screw centrifuge of claim 2, wherein the centrifuge drum is configured so that the material discharged at the outlet (14) has a specified radius (32) relative to a rotational axis of the centrifuge drum, and the shell (24) is formed with a radius (30) that is the same as the radius (32) of the material discharged at the outlet (14).

4. The solid-bowl screw centrifuge of claim 2, wherein the centrifuge drum is configured so that the material discharged at the outlet (14) has a specified radius (32) relative to a rotational axis of the centrifuge drum, and the shell (24) is formed with a radius that is greater than the radius (32) of the material discharged at the outlet (14).

5. The solid-bowl screw centrifuge of claim 1, wherein the energy recovery device (10) is formed in an area-symmetrical manner.

6. The solid-bowl screw centrifuge of claim 1, wherein the energy recovery device (10) is selectively securable in the first position (34) and in the second position (36).

7. The solid-bowl screw centrifuge of claim 1, wherein the outlet (14) is formed as an outlet opening in a drum end wall (12) of the centrifuge drum, and the energy recovery device (10) is attachable to the drum end wall (12) in a stationary manner in either of the first and second positions (34, 36), and wherein the first and second positions (34, 36) are offset from a radial direction (38) by equal but opposite angular amounts.

8. The solid-bowl screw centrifuge of claim 1, wherein the first active surface (20) of the energy recovery device (10) is inclined relative to the longitudinal axis to define a first deflecting surface (44) by way of which clarified material is deflectable from a largely axial direction of movement into a largely tangential direction of movement (48) when the centrifuge drum is rotated in the first direction of rotation (16), and the second active surface (22) is inclined relative to the longitudinal axis to define a second deflecting surface (46) by way of which clarified material is deflectable from a largely axial direction of movement into a largely tangential direction of movement (48) when the centrifuge drum is rotated in the second direction of rotation (18).

9. The solid-bowl screw centrifuge of claim 8, wherein the two active surfaces (20, 22) and the two deflecting surfaces (44, 46) are formed on a single shell (24).

10. The solid-bowl screw centrifuge of claim 1, further comprising a weir device (50) that is able to be brought into at least two positions together with the energy recovery device (10), and is formed integrally with the energy recovery device (10).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a front view of a first exemplary embodiment of an energy recovery device according to the invention.

(2) FIG. 2 shows the section II from FIG. 1.

(3) FIG. 3 shows a front view of a second exemplary embodiment of an energy recovery device according to the invention.

(4) FIG. 4 shows the section IV from FIG. 3.

(5) FIG. 5 shows a front view of a third exemplary embodiment of an energy recovery device according to the invention.

(6) FIG. 6 shows the section VI from FIG. 5.

(7) FIG. 7 shows a front view of the energy recovery device from FIG. 5 in a state mounted on a centrifuge drum for a first direction of rotation.

(8) FIG. 8 shows a front view of the energy recovery device from FIG. 5 in a state mounted on a centrifuge drum for a second direction of rotation.

DETAILED DESCRIPTION

(9) The figures illustrate energy recovery devices 10 which are each intended to be arranged on a drum end wall or end wall 12 of a centrifuge drum that is not illustrated further. In this case, a plurality of outlets 14 each in the form of a circular outlet opening are formed in the end wall 12 in a circular manner about the rotation axis of the centrifuge drum. In each case one of these outlets 14 is illustrated in the figures.

(10) The centrifuge drum is rotatable in a first direction of rotation 16 and in a second direction of rotation 18 that is opposite to this first direction of rotation 16. The energy recovery device 10 serves to recover energy from the clarified material flowing out of the outlet 14. The material flowing out there has kinetic energy corresponding to the rotational speed, and largely loses said kinetic energy at the transition into a stationary drain of the associated centrifuge. This kinetic energy can be partially intercepted by the energy recovery device 10 and transmitted back to the centrifuge drum so that less rotation energy has to be applied as a whole for the rotation of the centrifuge drum.

(11) To this end, the energy recovery device 10 comprises a first active surface 20, via which clarified material can flow out when the centrifuge drum is rotated in the first direction of rotation 16. Also formed on the energy recovery device 10 is a second active surface 22, via which clarified material can flow out when the centrifuge drum is rotated in the second direction of rotation 18. The two active surfaces 20 and 22 are both formed with a single shell 24 which projects in a largely perpendicular manner from the end wall 12 of the centrifuge drum, directly in front of the associated outlet 14, and at the same time is fastened in a stationary manner.

(12) Via the active surface 20, the material flowing out can (see FIG. 7) flow substantially only in a tangential manner and thus somewhat radially toward the outside, starting from the outlet 14. In particular, the radial flow path, starting from the center of the outlet 14, is limited to approximately 8 radially toward the outside, until the material flowing out can finally emerge freely radially toward the outside over a first overflow edge 26 on the right-hand rim of the shell 24 with reference to FIG. 7. The same applies for the second active surface 22 and a second overflow edge 28 with regard to the second direction of rotation 18 (see FIG. 8).

(13) To this end, with regard to the rotation axis of the centrifuge drum, the shell 24 has a radius 30 which corresponds to a radius 32 of the material discharged at the outlet 14, the pond surface as it is known.

(14) The outflow surface formed in such a way with the shell 24 and the two active surfaces 20 and 22 thereof can to this end be positioned in a simple manner on the end wall 12 in two positions, a first position 34 (FIG. 7) and a second position 36 (FIG. 8).

(15) In the two positions 34 and 36, the shell 24 is in each case in an inclined position at an angle of preferably between +/2 and +/20, particularly preferably +/10, with regard to a radial direction 38 of the associated outlet 14. In order to allow this positioning, the shell 24 is supported simply by means of a backplate 40 in which two slots 42 for fastening to the end wall 12 by means of screws (not illustrated) are formed.

(16) The shell 24 in FIGS. 1 and 2 is held by means of the backplate 40 so as to project perpendicularly from the end wall 12. In FIGS. 3 to 6, the shell 24 is designed in a manner rising axially toward the outside starting from the outlet 14. In this case, a deflection of the material flowing out into a largely tangential direction of movement 48 with the controlledly radial outward movement explained above is supported at a first deflecting surface 44 and a second deflecting surface 46, depending on the direction of rotation. The shell 24 thus forms a deflecting surface for the clarified material flowing out, said deflecting surface extending in an inclined manner in the longitudinal direction of the centrifuge drum from radially on the outside to radially on the inside. In this case, the shell 24 in FIGS. 3 and 4 is designed in a planar or straight (in particular not curved) manner in the longitudinal section, whereas the shell 24 in FIGS. 5 and 6 also has a curvature in the axial direction.

(17) The material flowing out passes onto the shell 24 at a weir device 50 formed within the backplate 40. The weir device 50 is formed with a weir edge 52 on the backplate 40, which, with the inclined positioning of the backplate 40, is then likewise advantageously in a somewhat inclined position, depending on the direction of rotation.

(18) Finally, it should be noted that all of the features which are mentioned in the application documents and in particular in the dependent claims are also intended, in spite of the formal back-reference made to one or more determined claims, to have protection in their own right individually or in any desired combination.

LIST OF REFERENCE SIGNS

(19) 10 Energy recovery device 12 End wall of a centrifuge drum 14 Outlet in the form of an outlet opening 16 First direction of rotation 18 Second direction of rotation 20 First active surface 22 Second active surface 24 Shell 26 First overflow edge 28 Second overflow edge 30 Radius of the shell 32 Radius of the material discharged at the outlet (pond surface) 34 First position 36 Second position 38 Radial direction 40 Backplate 42 Slot 44 First deflecting surface 46 Second deflecting surface 48 Largely tangential direction of movement 50 Weir device 52 Weir edge