REFINING SET

Abstract

The invention relates to a refining assembly for refining water-suspended pulp fibers between two coaxial refining surfaces which form a refining gap, rotate in relation to each other and are formed by refining bars and grooves extending therebetween. At least one directional component of the refining bars extends radially in relation to the axis of rotation. In order make the refining process more efficient, the refining bars have annular elevations and depressions that run concentrically to the axis of rotation of the refining surfaces and an annular elevation of one refining surface protruding into an annular depression in an opposite refining surface.

Claims

1. A refining assembly for refining aqueous suspended cellulose fibers, comprising: two refining surfaces arranged coaxially to one another and forming a refining gap, the two refining surfaces being rotatable relative to one another and are formed by refining bars and grooves extending between them, wherein at least one directional component of the refining bars extends radially relative to an axis of rotation, and wherein the refining bars have annular elevations and depressions that run concentrically to the axis of rotation of the refining surfaces, whereby an annular elevation of one refining surface protrudes into an annular depression of an opposite refining surface, refining sets that form the refining surface are fastened on a supporting surface, a spacing between the refining bars of the opposite refining surfaces in a radial direction is identical, a spacing between the grooves of the opposite refining surfaces in the radial direction is identical, and the grooves in the radial direction have a consistent height above the supporting surface.

2. The refining assembly according to claim 1, wherein a height of the annular elevation or respective depression is at least one of increasing gradually and decreasing gradually in the radial direction.

3. The refining assembly according to claim 1, wherein the elevations and depressions alternate in both refining surfaces in the radial direction.

4. The refining assembly according to claim 1, wherein the elevations and depressions extend only over a partial radial section of the refining surface.

5. The refining assembly according to claim 1, wherein the elevations and depressions extend over the entire refining surface.

6. The refining assembly according to claim 1, wherein at least some of the grooves are at least partially closed by barriers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

[0025] FIG. 1 is a schematic cross section through a refining arrangement, according to an embodiment of the invention;

[0026] FIG. 2 is a top view onto a refining disk, according to an embodiment of the invention; and

[0027] FIGS. 3-6 are partial radial cross section views through various refining disks, according to an embodiment of the invention.

[0028] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

[0029] According to FIG. 1, a refining gap 6 is formed in the housing of the refining assembly, including a stationary refining surface 2 that is coupled with the housing and a refining surface 3 that rotates about a rotational axis 7, according to an embodiment of the invention.

[0030] The two annular refining surfaces 2, 3 are positioned parallel to one another, wherein the distance between them is generally adjustable.

[0031] Rotating refining surface 3 is herein moved in rotational direction by a shaft 16 that is rotatably mounted in the housing. Shaft 16 is driven by a drive that is also located in the housing.

[0032] In the herein illustrated example, the fibrous suspension that is to be refined and which contains cellulose fibers 1 runs via an infeed through the center into refining gap 6 between the two refining surfaces 2, 3.

[0033] The fibrous suspension passes interacting refining surfaces 2, 3 in radially outward direction and exits the adjacent annulus through an outlet.

[0034] Means that are generally known with which power is generated in order to press the two refining surfaces 2, 3 against one another are not illustrated.

[0035] Both refining surfaces 2, 3 are respectively formed by several refining disks 14, 15 as illustrated in FIG. 2 that extend respectively over a circumferential segment of the corresponding refining surface 2, 3 and which are also referred to as refining sets.

[0036] Refining disks 14, 15 that are arranged closely adjacent next to one another provide a continuous refining surface 2, 3 in circumferential direction. Refining disks 14, 15 respectively are mounted on a flat supporting surface 17.

[0037] As illustrated in FIG. 2, refining disks 14, 15 and thus also refining surfaces 2, 3 are formed by a plurality of radially progressing refining bars 4 and grooves 5 between them.

[0038] The cross section of refining bars 4 which are also referred to as blades is generally rectangular. However, the scope of the present invention covers other shapes.

[0039] Grooves 5 between refining bars 4 also have a rectangular cross section and serve as flow channels for the fibrous suspension. The groove depth is generally between 2 and 20 mm.

[0040] So that the groove width does not become too large in radially outward direction at a constant and uniform width of refining bars 4, refining bars 4 can be split or newly added in radial direction 10.

[0041] According to an embodiment of the invention, refining bars 4 have annular elevations 8 and depressions 9 that run concentrically to axis of rotation 7 of refining surfaces 2,3, whereby an annular elevation 8 of one refining surface 2, 3 protrudes into an annular depression 9 of opposite refining surface 2,3.

[0042] Due to elevations 8 and depressions 9, turbulences are caused in the fibrous suspension that is to be treated. Moreover, when flowing through refining gap 6, the fibrous suspension is forced at least partially to shift between refining surfaces 2, 3.

[0043] The result is increased efficiency in refining.

[0044] FIGS. 3 to 6 illustrate various arrangements of refining surfaces 2,3, according to other embodiments of the invention. Regardless of said arrangements however, the distance between refining bars 4 of opposite refining surfaces 2, 3, and the distance between grooves 5 of opposing refining surfaces 2,3 in radial direction 10 is the same.

[0045] In FIG. 6, grooves 5 have a constant height above supporting surface 17 in radial direction 10, according to an embodiment of the invention. This means that the height of refining bars 4 relative to the groove bottom changes in radial direction 10.

[0046] In contrast thereto, grooves 5 contribute to the turbulence in the examples illustrated in FIGS. 3 to 5. This means that also grooves 5 have annular elevations 11 and depressions 12 that run concentrically to axis of rotation 7 of refining surfaces 2, 3, whereby an annular elevation 11 of one refining surface 2, 3 protrudes into an annular depression 12 of opposite refining surface 2,3.

[0047] To avoid blockages due to constrictions, the radial position of elevations 8 or respectively depressions 9 of refining bars 4 corresponds with the radial position of elevations 11 or respectively depressions 12 of grooves 5 of a refining surface 2, 3.

[0048] In FIGS. 3 to 5viewed in radial directionthe height of refining bars 4 above the groove bottom is the same.

[0049] It is for example however also possible that the height of grooves 5 relative to supporting surface 17 in radial direction 10 fluctuates less than the height of refining bars 4 relative to supporting surface 17.

[0050] In the interest of a homogeneous treatment during flow, elevations 8, 11 and depressions 9, 12 alternate in all arrangements and on both refining surfaces 2, 3 in radial direction 10.

[0051] In one embodiment, refining surfaces 2, 3 are to be designed depending upon cellulose fibers 1 that are to be treated and according to the requirements of such treatment.

[0052] FIG. 3 illustrates one design wherein the height of annular elevation 8, 11 or respectively depression 9, 12 on both refining surfaces 2, 3 as well as on refining bars 4 and grooves 5 gradually increases and gradually decreases in radial direction 10.

[0053] In FIG. 6 only the height of refining bars 4 changes gradually relative to supporting surface 17.

[0054] As shown in FIGS. 4 and 5, to further increase the level of turbulence, the height of annular elevation 8, 11 or respectively depression 9, 12 increases or decreases in radial direction 10 in one (FIG. 4) or several (FIG. 5) increments. In the case of several incrementsas illustrated in FIG. 5the transitions can progress perpendicular to the direction of flow.

[0055] In the case of only one increment between elevation 8, 11 and depression 9, 12 a slanted transition is to be recommended for minimization of wear and tear, according to FIG. 4.

[0056] In general, elevations 8, 11 and depressions 8, 12 extend over the entire refining surface 2, 3.

[0057] In many cases howeveras can be seen in FIGS. 1 and 2it is sufficient if elevations 8, 11 and depressions 9, 12 extend only over a partial radial section of refining surface 2, 3.

[0058] Additionally, barriers 13 can also intensify the fiber treatment, according to FIG. 5. Said barriers 13 close off grooves 5 completely or partially and can thus also support the shifting of the fibrous suspension between refining surfaces 2, 3.

[0059] While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.