Refiner plate with gradually changing geometry

Abstract

A refiner plate segment with a continuous transition zone spanning from the periphery or near the periphery of the plate in a substantial spiral toward the axis of rotation of the plate adjacent the breaker bar zone.

Claims

1. A refiner plate segment comprising: an outer periphery; an inner arc distally disposed from the outer periphery; a first lateral edge; a second lateral edge distally disposed from the first lateral edge; and a refining surface disposed between the outer periphery and the inner arc comprising: a pattern of bars and grooves disposed between the outer periphery and the inner arc in multiple bands, wherein the pattern of bars and grooves in each band of the multiple bands has a density, wherein each bar has ends, wherein the pattern of bars and grooves in a first band of the multiple bands disposed closer to the inner arc has a lesser density than a pattern of bars and grooves in an adjacent band of the multiple bands disposed closer to the outer periphery as measured along a radial line configured to extend from a center of rotation of the refiner plate segment when the refiner plate segment is mounted to a mechanical refiner; and a transition zone, wherein the transition zone is arranged at an angle of between 20 and 85 relative to the radial line, wherein the transition zone borders a side of at least one of the multiple bands, wherein the density of the pattern of bars and grooves increases within a band of the multiple bands as measured from a point on the band nearer the inner arc to a point on the band nearer the outer periphery, and wherein the transition zone is distributed across the refining surface.

2. The refiner plate segment of claim 1, wherein the transition zone is arranged at an angle of between 30 and 80 relative to the radial line.

3. The refiner plate segment of claim 1, wherein the transition zone is configured to align with a transition zone of an adjacent refiner plate segment to thereby form a spiral shape spanning a refining surface of a refiner plate assembly, wherein the refiner plate assembly comprises two or more refiner plate segments.

4. The refiner plate segment of claim 3, wherein the transition zone is distributed in a curve forming a spiral shape spanning at least 50% of the refining surface of the refiner plate assembly.

5. The refiner plate segment of claim 3, wherein the transition zone is distributed in a curve forming a spiral shape spanning at least 60% of the refining surface of the refiner plate assembly.

6. The refiner plate segment of claim 1, wherein the transition zone is distributed in a curve forming a spiral shape spanning at least 50% of the refining surface.

7. The refiner plate segment of claim 1, wherein the transition zone is distributed in a curve forming a spiral shape spanning at least 60% of the refining surface of the refiner plate segment.

8. The refiner plate segment of claim 7, wherein the transition zone has one or more discontinuities in the pattern of bars and grooves, the discontinuities amounting to less than 10% of the refining surface.

9. The refiner plate segment of claim 1, wherein the transition zone is distributed in a curve forming a spiral shape spanning at least 75% of the refining surface.

10. The refiner plate segment of claim 1, wherein the transition zone is radially distributed on at least 50% of the refining surface.

11. The refiner plate segment of claim 1, wherein the refining surface is mirrored along a central axis of the refiner plate segment, wherein the transition zone spans the refining surface, and wherein the transition zone is shaped like a V, a W, an inverted V, or an inverted W.

12. The refiner plate segment of claim 1, wherein the refining surface is disposed radially outward of a breaker bar section, wherein the breaker bar section is a first refining zone disposed closest to the inner arc of the refiner plate segment.

13. The refiner plate segment of claim 1, wherein the transition zone is configured to align with a transition zone of a right adjacent refiner plate segment and a left adjacent refiner plate segment to thereby form a spiral shape spanning a refining surface of a refiner plate assembly comprising three or more refiner plate segments, wherein the spiral shape of the refiner plate assembly extends from a radially outer perimeter to a radially inner perimeter of the refining surface.

14. The refiner plate segment of claim 1, wherein the refining surface is disposed on at least 30% of an area between the inner arc and the outer periphery.

15. The refiner plate segment of claim 1, wherein at least two bands of the multiple bands extend to the second lateral edge of the refiner plate segment, wherein a first band of the at least two bands is configured to align with a first adjacent band on an adjacent refiner plate segment, wherein a second band of the at least two bands is configured to align with a second adjacent band on the adjacent refiner plate segment, and wherein each of the first adjacent band and the second adjacent band extend to a first lateral edge of the adjacent refiner plate segment.

16. The refiner plate segment of claim 15, wherein the first adjacent band and the second adjacent band asymptotically approach a tangent line at the outer periphery of the adjacent refiner plate segment.

17. A refiner plate segment comprising: a refining zone having a pattern of bars and grooves wherein each bar has ends; and transition zones disposed on the refining zone to create X shapes, wherein diamond shapes are created in the refining zone by the X shapes created by the transition zones, and wherein a density of bars in the pattern of bars and grooves within each diamond shape increases radially from a first diamond shape nearer to an inner arc to an adjacent diamond shape further from the inner arc, wherein the transition zones are distributed across the refiner plate segment.

18. A refiner plate segment comprising: an outer periphery; an inner arc disposed across from the outer periphery; a first lateral edge; a second lateral edge disposed across from the first lateral edge; and a refining surface having a pattern of bars and grooves, wherein the refining surface is disposed between the inner arc and the outer periphery, the refining surface comprising: multiple transition zones, wherein the transition zones are disposed to adjacent transition zones, wherein each transition zone is distributed in a line across the refiner plate segment, wherein the line spans the refining surface at an angle of between 20 and 85 relative to a radial line passing through the refiner plate segment, wherein the radial line is configured to extend from a center of rotation of the refiner plate segment when the refiner plate segment is mounted to a mechanical refiner, wherein an area between adjacent transition zones forms a spiral band, wherein multiple adjacent transition zones form multiple spiral bands, wherein one or more bars span across two or more transition zones, wherein the pattern of bars has a density, wherein a transition zone of the multiple transition zones is defined by an increase in density between a first spiral band of the multiple spiral bands disposed closer to the inner arc and an adjacent spiral band of the multiple spiral bands disposed further from the inner arc, and wherein the density increases within the multiple spiral bands from a point of each spiral band disposed closer to the first lateral edge to a point of the spiral band disposed closer to the second lateral edge.

19. The refiner plate segment of claim 18, wherein the transition zone of the multiple transition zones is in a form of a V shape or an inverted V shape.

20. The refiner plate segment of claim 1, wherein the transition zone is defined by a structure selected from the group consisting essentially of: a full surface dam, a subsurface dam, connected and partially connected bar ends, or a combination thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a refiner plate segment having distinct bands of substantially constant width, each featuring substantially parallel bar patterns.

(2) FIG. 2 shows a refiner plate segment having distinct bands of substantially varying width, each featuring substantially parallel bar patterns.

(3) FIG. 3 shows a refiner plate segment for a plate where the direction of rotation of the plate is reversible and the transition zones are making an inverted V shape.

(4) FIG. 4 shows a reversible refiner plate segment where bars are positioned to form an X-shape transition zones.

(5) FIG. 5 shows a refiner plate segment transition zones, angle of transition and radial or annular line.

(6) FIG. 6 shows a refiner plate segment defining the radial or annular arc.

(7) FIG. 7 shows a refiner plate segment having distinct bands, each featuring substantially parallel bar patterns with a steeper angle for the transition zones.

(8) FIG. 8 shows a refiner plate segment having bands, where the ends of bars from adjoining bands are connected.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(9) The foregoing detailed description of the preferred embodiments is presented only for illustrative and descriptive purposes and is not intended to be exhaustive or to limit the scope and spirit of the invention. The embodiments were selected and described to best explain the principles of the invention and its practical application. One of ordinary skill in the art will recognize that many variations can be made to the invention disclosed in this specification without departing from the scope and spirit of the invention.

(10) Illustrative embodiments of a refiner plate design in accordance with multiple embodiments of refiner plate segments or sectors are shown in FIGS. 1-4 and FIGS. 7-8. An embodiment of a refiner plate segment (a sector) comprises a generally spiraling, continuous transition zone, which spans from an area near the exit area of the plate and extends toward a feeding area of the plate. Using this concept, a parallel arc drawn between the first and second arcs of a plate segment will intersect the continuous transition zone at least once such that part of the transition zone can be found at any radial location in the refining area of the refiner plate. Some bands of relatively short refining zones are thus created, which are generally angled relative to the outer periphery of the refiner plate segment. The angle of transition is the angle formed between the radial line and a line tangent to the transition zone, which is an angle of about 20 to 85. The visual bands thus created by the refining zones between the continuous and generally spiraling transition zone can have a constant width, or the width can vary from the outermost part of the band (relative to the annular location on the refiner plate) to the innermost part of the band. Many variations of this concept can be created, and the following figures are illustrative of the invention.

(11) A pattern for a refiner plate segment or sector for mounting on a refiner disc has been developed. The pattern comprises an outer radius at an outer periphery and an inner radius at an inner arc of the refiner plate segment or sector and a refining zone comprising a pattern of bars and grooves disposed between the outer periphery and inner arc in multiple bands. The patterns of bars in each band have a density, and the density of the bars in each band is greater from the zone nearest the inner arc to the zone nearest the outer periphery. A transition zone is distributed in a line forming a substantially spiral shape spanning the refining zone of the refiner plate mounted with refiner plate segments from approximately the outer periphery to approximately the inner arc of the refining zone, and the transition zone is arranged at an angle relative to a radial line passing through the segment of between 20 and 85.

(12) In some embodiments of the invention, a refiner plate segment comprises a refining zone having a pattern of bars and grooves and a continuous transition zone in the form of an X. These diamond shapes are created within the refining zone by the X shapes created by the transition zones. Additionally, the density of bars in the pattern of bars and grooves within each diamond shape becomes greater (denser) when moving radially from a diamond shape nearer to an inner arc to a diamond shape further from the inner arc.

(13) Additional embodiments include a refiner plate segment comprising a refining zone having a pattern of bars and grooves and a transition zone within the refining zone. The refining zone contains a transition zone forming spiral bands, and one or more bars span across two or more transition zones. The pattern of bars gets denser when crossing the transition zone in a direction from the inner arc toward the outer periphery. The refiner plate segment may include a first lateral edge and a second lateral edge, where the first lateral edge is closest to the inner arc of the refiner plate segment, and the second lateral edge is closest to the outer arc of the segment, and the pattern of bars gets denser moving in a direction from the first lateral edge to the second edge.

(14) The invention is directed to a refiner plate attached to a substantially circular disc (not shown) for installation in a rotating disc refiner, wherein the plate comprises a plurality of adjacent refiner plate segments 10, each segment 10 having a central axis 20 extending radially and a pattern of alternating raised bars 30 and grooves 40 defined between the bars 30. The bars 30 and grooves 40 extend substantially in parallel such that each bar 30 has a length defined by radially inner and outer ends.

(15) FIG. 1 shows a refiner plate segment 10 having distinct refining zone bands 50 of substantially parallel bars 30, each having a substantially constant length. In this embodiment, the density of bars 30 in a given band, e.g., 50a, 50b, and 50c, becomes greater (the bars 30 are more closely spaced) when moving tangentially and radially along a band, for example, the bars 30 from band 50a become more closely spaced when going from the second lateral edge 130 (nearest the inner arc 70 of the segment 10) to the opposite side of the segment 10 at the first lateral edge 120 (nearest the outer periphery 90 of the plate at the exit area). The density of the bars 30 also becomes greater when moving radially toward the outer periphery 90 of the plate segment 10 from one band 50 of bars 30 to the next band 50 of bars 30 (for example, from band 50a to 50b, and from band 50b to 50c). This spacing change between the bands 50 of bars 30 in the radial direction results in a continuous, less restricted flow of material over the surface of the refiner plate segment 10, providing a more even distribution of material over the refining zone 110.

(16) The refiner plate segment 10 further comprises a breaker bar zone 100 characterized by very coarse bars 30 and grooves 40 where feed material is reduced in size and given a radial component of movement (from the inner arc 70 of the refiner plate segment 10 toward the outer periphery 90) without substantial refining action. Breaker bar zones 100 are not present in every refiner plate segment and do not affect the scope of this invention. The refining zone 110 receives the material from the breaker bar zone 100 and initially performs a relatively coarse refining action, and as the feed material is moved toward the outer periphery 90 of the plate segment 10 the gradual change to relatively fine, closely spaced bars 30 and grooves 40 provides a gradually higher degree of refining within the refining zone 110.

(17) The embodiment of FIG. 1 shows a refiner plate segment 10 having clear distinct bands 50 of a bar pattern which may be separated by dams 140. The angle of transition is formed by the tangent to the edge of the transition zone 55 and the central axis 20 extending through the center of the plate segment 10 from the inner arc 70 to the outer periphery 90 perpendicular to the outer periphery 90, shown at angle . Along these angled bands 50, the bars 30 are substantially parallel. Each band 50 of the segment 10 starts at a first lateral edge 120 of the segment 10 and runs in a curved or diagonal approximate line toward a second lateral edge 130, either toward (inward) or away from (outward) the inner arc 70. In the exemplary embodiment shown in FIG. 1, starting at the first lateral edge 120 of the segment 10 on the left-hand side, the band 50 moves inward to the second lateral edge 130 on the right-hand side toward the inner arc 70.

(18) The density of the bars 30 gets greater (the bars 30 become more closely spaced) within any given band 50 when moving from a transition zone 55 at the first edge 60 (the edges of band 50b are shown here as an example) of the band 50 (nearest the inner arc 70) to a transition zone 55 at the second edge 80 of the band 50 (nearest the outer periphery 90). The spacing of the bars 30 can change gradually at every bar 30, every few bars 30, or even change once, twice or more times across the entire band 50. Additionally, when moving annularly outward (toward the outer periphery 90) from one band 50 to the next band 50 (for example, from band 50a to band 50b), the bars 30 are more closely spaced in the annularly outward band 50 (in this example, 50b).

(19) The effect of this change of bar spacing laterally across the bands 50, (or diagonally) in addition to the annularly (from one band 50 to the next in a direction toward the outer periphery 90, for example, from 50a to 50b to 50c,) in certain embodiments creates a very gradually changing bar spacing moving outward in a radial direction in which the bar pattern gradually gets denser (finer) toward the outer periphery 90 without any large change at any annular location that could cause a peak in flow restriction.

(20) The bands 50 are separated by a continuous surface dam 140 in the outermost transition zones 55 in this case, while a continuous subsurface dam 150 is used to connect the ends of the bars 30 at the innermost transition zones 55. The use of surface and subsurface dams (140, 150) can vary within alternative embodiments, and transition zones 55 featuring no dam are also possible, with the ends of the bars 30 being square, chamfered, connected or separate as required to achieve the right feeding or restrictive effect.

(21) Because the transition zone 55 spans the surface of the refiner plate in a spiral/concentric manner, there is no annularly-concentrated transition area that could cause a peak in flow restriction for the feed material. Additionally, when using a continuous surface dam 140 as a transition zone 55, as shown in FIG. 1 for the outer bands 50 of bars 30, such a surface dam 140 is also radially evenly distributed over the plate and cannot cause any annular concentration of feed material due to many surface dams 140 being found on a similar annular location.

(22) In this first embodiment, the bands 50 of bars 30 are of substantially constant length l and thus parallel to one another, and they are continuous, so that when placing two plate segments 10 side-by-side, the bands 50 of bars 30 will form a substantially continuous set of spiral bands 50 connected at the first and second edges 60, 80. While this feature is present in a preferred embodiment, other embodiments comprise bands 50 that do not directly align at the first and second edges 60, 80. These patterns still provide an effectively gradual transition from a coarse pattern of bars 30 and grooves 40 to a relatively finer pattern of bars 30 and grooves 40 from the inner arc 70 to the outer periphery 90, with no clear transition zone 55 that would tend to cause uneven radial accumulation of feed material on the surface of a refiner plate mounted with plate segments 10 as described herein.

(23) Using this concept, a parallel arc drawn across the plate segment 10 at any radial location from the first lateral edge 120 to the second lateral edge 130 will intersect the substantially continuous transition zone 55 at least once. Said another way, part of the transition zone 55 can be found at any radial location in the refining zone 110 of the refiner plate mounted with the refiner plate segments 10 shown herein. The effect is to create some bands 50 of relatively short refining zones 110, which are generally angled relative to the radial line and a tangent to the transition zone 55. The angle of transition can be from about 20 to 85, and preferably from 30 to 80. The visual bands 50 thus created by the refining zones 110 between the substantially continuous and generally spiraling transition zone 55 can have bars 30 of a constant length l, or the length l can vary. Additionally, the width w of the bars within a visual band 50 can be constant or vary.

(24) Ideally, the gradually changing geometry (pattern) described herein for all embodiments covers at least 50% (or 60% or 75%) of the surface of the refining zone of the plate segment 10 (the refining zone is the area of the plate segment excluding the breaker bar zone 100). There can be some minor discontinuity, such as no more than 10%, in the transition zone 55, while remaining within the scope or spirit of the invention. Specifically, the transition zone may have one or more discontinuities in the pattern of bars and grooves that amount to less than 10% of the surface area of the refining zone. For the purpose of this disclosure, a discontinuity is a pattern substantially, but not completely covering the entire refining zone due to the pattern of bars and grooves falling short of reaching the refiner plate segment edges (the spiral is not flush with the edges of the plate, causing the transition zone to stop at a given radius and start again at a slightly different radius.

(25) FIG. 2 shows a second embodiment of a refiner plate segment 210 with a gradually changing geometry having distinct bands 250 comprised of a pattern of substantially parallel but varying length l bars 230. In this embodiment, the bands 250 of substantially parallel bars 230 are of variable length l, having a shorter length l toward the outer periphery 290 compared to the length l of the bars 230 nearest the inner arc 270. The remaining features of the embodiment shown in FIG. 2 are similar to those described in FIG. 1. The density of bars 230 in a given band 250 becomes greater (more closely spaced) when following the band 250 spirally starting at the inner arc 270 and moving along the band 250 toward the outer periphery 290. The density of bars 230 also increases when moving from one band 250 to the next band 250 from the inner arc 270 toward the outer periphery 290. This change in the density of the bars 230 between the bands 250 in these directions results in a continuous, less restricted flow of material over the surface of the refiner plate segment 210.

(26) FIG. 3 shows an embodiment of a refiner plate segment 310 with a gradually changing geometry that is reversible. In this case, the transition zone 355 forms a V-shape, or an inverted V-shape, because the same feeding features are desired in both directions of rotation of a refiner plate mounted with refiner plate segments 310. The bands 350 of substantially parallel bars 330 do not continuously extend in a spiral fashion; they are a mirror of the pattern across the central axis of plate segment 310. This pattern provides the same gradual change of bar density (the spacing of the bars 330) and even distribution of transition zones 355 and dams 340 as FIGS. 1 and 2, but in a reversible version.

(27) FIG. 4 shows yet another embodiment of a reversible refiner plate segment 410 with a gradually changing geometry. In this case, instead of using a transition zone 455 that forms a V-shape, the transition zone 455 of this embodiment forms an X-shape, and also forms a substantially continuous spiral, crossing itself in both directions (spiraling toward the inner arc 470 from the first lateral edge 425 to the second lateral edge 435, and spiraling toward the inner arc 470 from the second lateral edge 435 to the first lateral edge 425). Again, the density of the bars 430 becomes gradually greater (the spacing becomes narrower) moving from the inner arc 470 toward the outer periphery 490. In this exemplary embodiment, the bars 430 are substantially parallel with substantially equal spacing in each diamond-shaped refining area 450 created by the crossing transition zones 455. The density of the bars 430 increases with each radial step from diamond 450 to diamond 450 from the inner arc 470 toward the outer periphery 490.

(28) FIG. 5 shows the location of transition zones 540 between bands of bars and grooves in a plate segment such as the one depicted in FIG. 1. A tangent line 520 to a transition zone 540 intersects the radial line 510 to form the angle of transition . The radial line 510 is formed by a line perpendicular to the outer periphery 550 passing through the axis of rotation.

(29) FIG. 6 shows a parallel arc 640, wherein all points of the parallel arc 640 are equidistant from the axis of rotation 650 of the refiner plate, and parallel to (or a constant distance from) the periphery 610 of the plate segment. On any parallel arc 640 in the refining zone, one or more spiraling transition zones will be crossing it.

(30) FIG. 7 shows another embodiment of a refiner plate segment 710, similar to FIG. 2, where the transition zones 755 have a steeper angle of transition than shown in FIG. 1 or 2. As in FIG. 2, the pattern of bars 730 gets denser when crossing a transition zone 755 toward the periphery 790 of the refiner plate segment 710 or sector. The pattern of bars 730 also gets denser within each band 750 of refining surface, when spiraling outward toward the outer periphery 790. The steeper angle of transition may be beneficial in certain applications, as opposed to less angled transition zones such as shown in FIGS. 1 and 2.

(31) FIG. 8 shows another embodiment of a refiner plate segment 810 in which the ends of the bars 830 of each spiral band 850 are connected (some bars 830 span across transition zones 855 rather than having a terminus or coinciding with a transition zone 855). The three spiral lines 802, 803, and 804 drawn over the pattern of bars 830 and grooves 840 show where the transition zones 855 are located, e.g., where the pattern of bars 830 gets denser when crossing a transition zone 855 toward the outer periphery 890 of the refiner plate segment 810. The pattern of bars 830 and grooves 840 gradually gets finer (denser) moving from the second lateral edge 833 of the refiner plate segment 810 to the first lateral edge 834 of the refiner plate segment 810 within a band 850, and also going from band to band (for example, from band 850a to band 850b) when moving radially toward the outer periphery 890 of the plate segment 810. This spacing change between the bands 850 of bars 830 in the radial direction results in a continuous, less restricted flow of material over the surface of the refiner plate segment 810, providing a more even distribution of material over the refining region. In this embodiment, the transition zones 855 between bands 850 are achieved with connections 895 between each of the bands 850. The transition zone 855 of this embodiment can have many different variations, for example, it is possible to connect some of the bars 830 while part of the transition zones 855 contains dams and/or discontinuities.

(32) It is to be understood that the present invention is by no means limited to the particular constructions and method steps herein disclosed or shown in the drawings, but also comprises any modifications or equivalents within the scope of the claims known in the art. It will be appreciated by those skilled in the art that the devices herein disclosed will find utility with respect to multiple refiner plate applications and the like.