Abstract
A refiner for refining pulps, includes a shaft, a rotor disc attached firmly to the shaft and a shaft bearing, the rotor disc being disposed between two stator discs and forming a refining chamber between the rotor disc and the stator discs. The shaft is movable in an axial direction and the shaft bearing is connected hydraulically to the refining chamber, ensuring low wear on the rotor discs and stator discs and, in particular, on the refiner plates on these discs, also in continuous operation.
Claims
1-13. (canceled)
14. A refiner for refining pulps in a fibre pulp suspension, comprising: a shaft (1) extending in an axial direction and being movable in the axial direction (7); a rotor disc (2) attached to the shaft (1); a shaft bearing (3) associated with the shaft (1); and two stator discs (4, 5) positioned with the rotor disc (2) disposed between them, thereby forming a refining chamber (6) between the rotor disc (2) and stator discs (4, 5), at least one of the stator discs (4, 5) being slidable in the axial direction (7) and the refining chamber (6) having an adjustable size via adjustment of a spacing between the respective stator discs (4, 5), wherein the rotor disc (2) is movable between the stator discs (4, 5) by movement of the shaft (1) in the axial direction (7), and the shaft bearing (3) is connected hydraulically to the refining chamber (6).
15. The refiner according to claim 14, wherein the rotor disc (2) is attached to the shaft (1) at an axial position inside or outside the shaft bearing (3).
16. The refiner according to claim 14, wherein the shaft bearing (3) is a fluid-lubricated plain bearing (23), wherein a fluid can be fed to the refining chamber (6) via the shaft bearing (3).
17. The refiner according to claim 16, wherein the fluid is water.
18. The refiner according to one of claim 14, comprising a seal (8) positioned between the refining chamber (6) and the shaft bearing (3).
19. The refiner according to claim 18, wherein the seal (8) exhibits a first sealing effect when the fluid flows in a relative direction through the shaft bearing (3) into the refining chamber (6) and exhibits a second sealing effect when the fluid flows in a relative direction out from the refining chamber (6) into the shaft bearing (3), the second sealing effect being different than the first sealing effect.
20. The refiner according to claim 19, wherein the rotor disc (2) is attached to the shaft (1) at an axial position inside or outside the shaft bearing (3).
21. The refiner according to claim 19, wherein the shaft bearing (3) is a fluid-lubricated plain bearing (23), wherein a fluid can be fed to the refining chamber (6) via the shaft bearing (3).
22. The refiner according to claim 21, wherein the second sealing effect is greater than the first sealing effect.
23. The refiner according to claim 19, wherein the second sealing effect is greater than the first sealing effect.
24. The refiner according to claim 19, comprising a damping element (9) associated with the shaft bearing (3) and disposed between the rotor disc (2) and a motor (10).
25. The refiner according to claim 14, comprising a damping element (9) associated with the shaft bearing (3) and disposed between the rotor disc (2) and a motor (10).
26. The refiner according to claim 25, comprising a coupling (11) disposed between the rotor disc (2) and the motor (10), wherein the damping element (9) is disposed between the rotor disc (2) and a coupling (11).
27. The refiner according to claim 25, wherein the damping element (9) is hydraulically connected to the shaft bearing (3).
28. The refiner according to claim 14, wherein the fibre pulp suspension can be fed to the refining chamber (6) through an inlet area (12) or through the shaft (1).
29. The refiner according to claim 28, wherein the rotor disc (2) include openings (13) that provide substantially even distribution of the fibre pulp suspension in the refining chamber (6) being fed through the inlet area (12) or shaft (1).
30. The refiner according to claim 14, wherein the shaft (1) is connected via a coupling (11) to a motor (10) and movement of the shaft (1) in the axial direction (7) can be absorbed by the coupling (11).
31. The refiner according to claim 19, wherein the shaft (1) is connected via a coupling (11) to a motor (10) and movement of the shaft (1) in the axial direction (7) can be absorbed by the coupling (11).
32. The refiner according to claim 30, wherein the coupling (11) is a curved-teeth coupling, allowing radial and axial movement of the shaft is possible in the curved-teeth coupling.
33. The refiner according to claim 14, characterized in that the shaft (1) is supported entirely on fluid-lubricated plain bearings (23).
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The invention will now be described using the examples in the drawings.
[0018] FIG. 1 shows a refiner according to the state of the art.
[0019] FIG. 2 shows an embodiment of a refiner according to the disclosure.
[0020] FIG. 3 shows details of the shaft bearing according to the disclosure.
[0021] FIGS. 4A and 4B show advantageous seals.
DETAILED DESCRIPTION
[0022] FIG. 1 shows a refiner according to the state of the art. Here, a rotor disc 2 is disposed on a shaft 1 in a housing 19, the rotor disc 2 being movable in axial direction 7 in relation to the shaft 1. The fibre pulp suspension is fed to the refiner 17 through an inlet area 12 and distributes itself in the refining chamber 6 through openings 13 (not shown) in the rotor disc 2. Here, the fibre pulp suspension is refined in a first refining gap between the rotor disc 2 and the first stator disc 4 and in a second refining gap between the rotor disc 2 and the second stator disc 5 and leaves the refiner 17 through the outlet area 18. Exchangeable refiner plates are disposed on the rotor disc 2 and the stator discs 4, 5. The second stator disc 5 can be moved in axial direction by means of an adjusting device 20, and the spacing between the stator discs 4, 5 and between the rotor disc 2 and the stator discs 4, 5, respectively, can be set. The axial movement of the rotor disc 2 on the shaft permits autonomous centering of the rotor disc 2 between the two stator discs 4, 5, where comparable refining gaps form. This design of refiner 17 does not provide for any movement by the shaft 1 in axial direction 7, the shaft bearing 3 being designed as an anti-friction bearing. The shaft bearing 3 and the refining chamber 6 are clearly separated. The anti-friction bearings are oil-lubricated. A seal 8 seals off the refining chamber 6 and the inlet area 12 towards the shaft 1. The design should prevent any oil from entering the refining chamber 6, and no fibre pulp suspension should be able to enter the oil circulating system for the anti-friction bearing.
[0023] FIG. 2 shows a refiner in an overhung arrangement. Here, a rotor disc 2 is disposed on a shaft 1 in a housing 19, the rotor disc 2 being firmly attached to the shaft 1 and the shaft 1 being movable in axial direction 7. The fibre pulp suspension is fed to the refiner 17 through an inlet area 12 and distributes itself in the refining chamber 6 through openings 13 (not shown) in the rotor disc 2. Here, the fibre pulp suspension is refined in a first refining gap between the rotor disc 2 and the first stator disc 4 and in a second refining gap between the rotor disc 2 and the second stator disc 5 and leaves the refiner 17 through the outlet area 18. Exchangeable refiner plates are disposed on the rotor disc 2 and the stator discs 4, 5. The second stator disc 5 can be moved in axial direction via an adjusting device 20, and the spacing between the stator discs 4, 5 and between the rotor disc 2 and the stator discs 4, 5, respectively, can be set. The axial movement of the shaft 1 and thus of the rotor disc 2 firmly attached to the shaft 1 permits autonomous centering of the rotor disc 2 between the two stator discs 4, 5, with comparable refining gaps forming. In accordance with movement of the shaft 1 in axial direction 7, the shaft 1 is connected to a motor 10 (not shown) via a coupling 11, the coupling 11 being able to absorb the movement of the shaft 1 in axial direction 7. The shaft 1 is mounted in an overhung arrangement by means of a shaft bearing 3, the rotor disc 2 being disposed outside the shaft bearing 3. The shaft bearing 3 is connected hydraulically to the refining chamber 6. Here, the shaft bearing 3 is designed as a fluid-lubricated plain bearing 23, where a fluid—preferably water—serves as lubricant in the shaft bearing 3 and can be at least partly fed to the refining chamber 6 through the shaft bearing 3. The seal 8 disposed between the shaft bearing 3 and the refining chamber 6 limits the amount of fluid flowing according to the pressure conditions between the shaft bearing 3 and the refining chamber 6. Advantageously, the fluid is guided systematically out of the shaft bearing 3 towards the refining chamber 6. This is achieved by the higher pressure of the fluid in the shaft bearing 3 compared to the pressure in the refining chamber 6. In this way, no fibre pulp suspension and no pulp from the refining chamber 6 can enter the shaft bearing 3. It is also appropriate to implement a seal 8 with a sealing effect that depends on the flow direction of the fluid. A seal 8 that has a lesser sealing effect when the fluid flows through the shaft bearing 3 into the refining chamber 6 than when the fluid flows out of the refining chamber 6 into the shaft bearing 3 is particularly advantageous. Thus, if there is higher pressure in the refining chamber 6 and lower pressure in the shaft bearing 3, fibre pulp suspension flowing from the refining chamber 6 into the shaft bearing 3 can be reduced to a minimum or prevented entirely. Advantageously, the refiner 17 also comprises a damping element 9 for the shaft bearing 3. The damping element 9 is disposed between rotor disc 2 and motor 10 (not shown) and preferably between rotor disc 2 and coupling 11. The damping element 9 can be connected hydraulically to the shaft bearing 3, the damping element 9 comprising a damping area 15 and a throttle element 16. The fluid fed to the shaft bearing 3 flows through the shaft bearing 3 here and also fills the damping area 15. The volume of the damping area 1 can be changed by moving the shaft 1 in axial direction 7, where fluid flows towards the damping element 9 when the volume of the damping area 15 increases and fluid flows away from the damping element 9 when the volume of the damping area 15 decreases, the fluid flowing towards and away from the damping area 15 through the throttle element 16 in each case.
[0024] FIG. 3 shows details of an overhung shaft bearing 3 according to the disclosed embodiments. The fluid is fed to the shaft bearing 3 though a fluid inlet 21 and flows through the fluid-lubricated plain bearing 23, filling the damping area 15. The seal 8 is disposed between shaft bearing 3 and refining chamber 6 and restricts the amount of fluid flowing in accordance with the pressure conditions between shaft bearing 3 and refining chamber 6, the greater part of the fluid being discharged from the shaft bearing 3 through the fluid return line 22. Advantageously, the fluid is guided systematically towards the refining chamber 6 by the fluid having a higher pressure in the shaft bearing 3 compared to the pressure in the refining chamber 6. The damping element 9 is connected hydraulically to the shaft bearing 3 and comprises the damping area 15 and the throttle element 16. The throttle element 16 is connected to the shaft 1 in FIG. 3, the damping area 15 being delimited by the shaft 1, the bearing housing 14 and the throttle element 16. The volume of the damping area 15 can be changed by moving the shaft 1 in axial direction 7, where fluid flows towards the damping element 9 when the volume of the damping area 15 is increased and fluid flows away from the damping element 9 when the volume of the damping area 15 decreases, the fluid flowing towards and away from the damping area 15 through the throttle element 16 in each case.
[0025] FIGS. 4A and 4B each show an advantageous seal 8 for the shaft bearing 3 that enables a sealing effect dependent on the flow direction of the fluid. The seal 8 is secured in the bearing housing 14 by a fastening element 24, the sealing lips 25 facing the shaft 1. In accordance with the truncated cone shape of the sealing lips 25, a lesser sealing effect is obtained when the fluid flows through the shaft bearing 3 into the refining chamber 6 than when the fluid flows out of the refining chamber 6 into the shaft bearing 3. The fluid flowing from the base to the imaginary tip of the truncated cone-shaped sealing lip 25—and thus from the shaft bearing 3 towards the refining chamber 6—causes the sealing lip 25 to expand and the sealing lip 25 to lift off the shaft 1, or at least reduces the pressing force of the seal 8, which is important for the seal 8 and the sliding friction, against the shaft. If the direction of flow is reversed, i.e. the fluid flows from the imaginary tip of the cone to the base of the truncated cone-shaped sealing lip 25—or from the refining chamber 6 towards the shaft bearing 3—the fluid presses the sealing lip 25 against the shaft 1 and causes the pressing force of the sealing lip 25 on the shaft 1 to increase. FIG. 4A shows a seal 8 with two free-standing sealing lips 25. FIG. 4B shows a seal 8 with two sealing lips 25, one free-standing sealing lip 25 being disposed closer to the shaft bearing 3 and the sealing lip 25 that is disposed closer to the refining chamber 6 having no cavity 26 facing towards the refining chamber 6, which advantageously avoids pulp being deposited there and possibly hardening of pulp in the cavity 26 facing the refining chamber 6.
[0026] The disclosed embodiments thus offer numerous advantages. The lower wear on the rotor discs and stator discs—especially on the refiner plates on these discs—achieved by very smooth positioning of the rotor disc, which is also retained in continuous operation, is particularly advantageous. Here, the disclosed embodiments prevent any contamination by pulp in the area of the seal and the bearing. Similarly, the disclosed bearing avoids the risk of oil contaminating the fibre pulp suspension because the bearing can be operated without oil, as well as eliminating or minimizing the risk of the pulp contaminating the bearing. The bearing also permits a more compact refiner design and, above all, a shorter overall length.
REFERENCE NUMERALS
[0027] (1) Shaft [0028] (2) Rotor disc [0029] (3) Shaft bearing [0030] (4) First stator disc [0031] (5) Second stator disc [0032] (6) Refining chamber [0033] (7) Axial direction [0034] (8) Seal [0035] (9) Damping element [0036] (10) Motor [0037] (11) Coupling [0038] (12) Inlet area [0039] (13) Openings [0040] (14) Bearing housing [0041] (15) Damping area [0042] (16) Throttling element [0043] (17) Refiner [0044] (18) Outlet area [0045] (19) Housing [0046] (20) Adjusting device [0047] (21) Fluid inlet [0048] (22) Fluid return line [0049] (23) Fluid-lubricated plain bearing [0050] (24) Fastening element [0051] (25) Sealing lip [0052] (26) Cavity
