Refiner plate with grooves that prevent clogging

Abstract

The refiner plate includes at least one refining zone including a first plurality of refining bars and a plurality of grooves, wherein at least one of the plurality of grooves has a first width between adjacent refining bars of the first plurality of refining bars at an entrance to the at least one refining zone that is narrower than a second width along the remainder of the at least one groove, and at least one of the adjacent refining bars of the first plurality of refining bars has a widened portion that widens in the circumferential direction of the refiner plate at an entrance portion of the at least one refining zone.

Description

[Technical Field]

[0001] Unless otherwise indicated herein, the materials in this section are not, or are not admitted to be, prior art to the claims of this application by inclusion in this section. [Background technology]

[0002] Refining lignocellulosic materials often requires the application of low-intensity refining energy to the furnish (e.g., stock). Refining is typically achieved using refiner plate designs featuring an array of roughly parallel bars and grooves, with the intensity of the refining energy defined by the inverse of the number of bars. Low-intensity refining is achieved using refiner plates with a high number of bars. In all applications, especially when refining low-consistency stocks, typically 3.0-5.5% fiber with the remainder being water, there comes a point when the grooves become significantly more susceptible to clogging with unseparated particles such as wood chips, wood particles, and paper fragments, fiber bundles, or (especially in the case of recycled grades) contaminants such as plastic chips, metal chips, and stone chips.

[0003] The plugging point is primarily related to the width of the grooves compared to the size of larger particles. Generally, when particle size is similar to or slightly larger than the width of the grooves, centrifugal forces and / or the flow pattern of the incoming material through the plates can force particles into the groove entrance. When the particle size difference and compressibility match, they become trapped and tightly packed within the grooves, blocking them. Over time, as more and more grooves become plugged, the maximum flow rate through the refiner gradually decreases. The effects of plugging can significantly shorten the lifespan of refiner plates and often require a plant shutdown for unscheduled maintenance and plate replacement.

[0004] Refiner plate designs typically use bars with constant width, but some use bars with tapered widths, either narrowing at the entrance to a zone or widening at the entrance to a zone. Some designs feature varying bar widths between zones, e.g., wider bars in lower bar density zones, but bar widths can be nearly constant, as shown in Figure 10, or vary very gradually within a given refining zone. Figure 10 shows bars 1010a-c and grooves 1020a-b with nearly constant widths. Feedstock particles flowing in the flow direction 1030 compress as they enter the grooves 1020a-b, potentially clogging the constant-width grooves 1020a-b.

[0005] One method to prevent plugging is to use refiner plates with wider grooves, which results in higher refining intensity and insufficient fiber defibration. Diverging groove widths (narrowest at the entrance to the refining section of the bar and gradually widening toward the periphery) offer some improvement in reducing plugging, since particles that fit just through the entrance should also be able to advance through the wider grooves along their length. Unfortunately, this benefit is limited by two factors: first, the rate at which groove width increases is typically too gradual to provide the necessary plugging protection, and plugging of these grooves is frequently observed; and second, diverging grooves typically require fewer bar intersections for material processing than parallel bar designs, thus defeating the desired goal of increasing bar intersections.

[0006] What is needed is a refiner plate design that allows for narrower grooves than the material would normally pass through without increasing clogging tendency, ensuring maximum flow through the refiner throughout the life of the refiner plate and allowing for low intensity refining of the furnish to maximize its properties.

[0007] BRIEF DESCRIPTION OF THE DRAWINGS Aspects and features of various embodiments will become more apparent by describing, by way of example, the following examples with reference to the accompanying drawings. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing narrowed grooves at the refining zone entrance between refining bars of a refiner plate according to some embodiments of the present disclosure. [Figure 2] 1A-1C show examples of refining bar patterns at the entrance to the refining zone of a refiner plate according to some embodiments of the present disclosure. [Figure 3A] 1A-1C are diagrams illustrating example refining bar transition shapes for providing narrowed grooves at the entrance to the refining zone, and side views of the corresponding refining bars, according to some embodiments of the present disclosure. [Figure 3B] 1A-1C are diagrams illustrating example refining bar transition shapes for providing narrowed grooves at the entrance to the refining zone, and side views of the corresponding refining bars, according to some embodiments of the present disclosure. [Figure 3C] 1A-1C are diagrams illustrating example refining bar transition shapes for providing narrowed grooves at the entrance to the refining zone, and side views of the corresponding refining bars, according to some embodiments of the present disclosure. [Figure 3D] 1A-1C are diagrams illustrating example refining bar transition shapes for providing narrowed grooves at the entrance to the refining zone, and side views of the corresponding refining bars, according to some embodiments of the present disclosure. [Figure 3E] 1A-1C are diagrams illustrating example refining bar transition shapes for providing narrowed grooves at the entrance to the refining zone, and side views of the corresponding refining bars, according to some embodiments of the present disclosure. [Figure 3F]1A-1C are diagrams illustrating example refining bar transition shapes for providing narrowed grooves at the entrance to the refining zone, and side views of the corresponding refining bars, according to some embodiments of the present disclosure. [Figure 3G] 10A-10C illustrate examples of transition shapes on the chamfers of the refining bars at the inlet, according to some embodiments of the present disclosure. [Figure 3H] 10A-10C illustrate examples of transition shapes on the chamfers of the refining bars at the inlet, according to some embodiments of the present disclosure. [Figure 3J] FIG. 10 shows an example of a refining bar that provides a narrowed groove at the entrance to the refining zone and increases in width along the length of the refining bar, according to some embodiments of the present disclosure. [Figure 4] 1A-D illustrate examples of chamfers or bevels on refining bars according to some embodiments of the present disclosure. [Figure 5] 1A-1C show examples of refining bar arrangements to provide narrowed grooves at the entrance to the refining zone of a refiner plate according to some embodiments of the present disclosure. [Figure 6] 1 shows an example of alternating length refining bars for providing narrowed grooves at the refining zone entrance, according to some embodiments of the present disclosure. [Figure 7] FIG. 10 shows an example of a refining bar for providing a narrowed groove at the entrance of the outer refining zone, the refining bar not being coupled to the inner refining zone, according to some embodiments of the present disclosure. [Figure 8] FIG. 10 shows an example of a refining bar for providing a narrowed groove at the entrance of the outer refining zone, the refining bar being partially coupled to the inner refining zone, according to some embodiments of the present disclosure. [Figure 9] FIG. 10 shows an example of alternating refining bars for providing narrowed grooves at the refining zone entrance, according to some embodiments of the present disclosure. [Figure 10] FIG. 1 illustrates the bars and grooves of a conventional refiner plate and the flow direction of the feedstock. DETAILED DESCRIPTION OF THE INVENTION

[0009] While specific embodiments are described, these embodiments are provided for illustrative purposes only and are not intended to limit the scope of protection. The devices, methods, and systems described herein may be embodied in various other forms. Furthermore, various omissions, substitutions, and changes may be made in the form of the exemplary methods and systems described herein without departing from the scope of protection.

[0010] In embodiments of the present disclosure, particle size filtering can be performed at the inlets of the grooves of a refiner plate. Filtering at the inlets of the grooves can prevent particles prone to clogging from entering the grooves. Any particles passing through the inlets of the grooves are unlikely to become clogged within the grooves after the inlet point. The inlet of particle size filtering can be applied to the inlet of any zone that is deemed prone to clogging based on the groove width and the condition of the incoming material. For example, particle size filtering can be applied to the inlets of all refining zones of a refiner plate (e.g., the inner end), the inlets of less than all refining zones of a refiner plate, or the inlet of only one zone of a refiner plate.

[0011] According to aspects of the present disclosure, inlet filtering can be achieved by forming narrow grooves using refining bars that are wider at the entrance to the refining zone than along the remaining length of the groove. The wider refining bars can be formed by widening the bars as a step, a chamfer, a curved profile, or a combination of these configurations. The widened portions of the bars can be formed on only one side of the bar, or they can be distributed regularly or irregularly between the two sides of the bar. The widened portions can be short, which prevents them from becoming a trapping point for particles. If a particle can just squeeze through the entrance of the narrowed groove by the widened bar, the particle should be able to continue flowing freely along the remainder of the groove.

[0012] FIG. 1 is a perspective view showing a narrow groove 140 between refining bars 100a, 100b of a refiner plate according to some embodiments of the present disclosure. In some embodiments, the refiner plate may be a unitary ring or a unitary cone. In some embodiments, multiple refiner plate segments may form a ring- or cone-shaped refiner plate. As shown in FIG. 1, the widened refining bars 100a, 100b may include widened sections 110a, 110b and narrow sections 120a, 120b around the circumference of the refiner plate or refiner plate segment. A chamfered transition section 130a, 130b may transition between the widened sections 110a, 110b and the narrow sections 120a, 120b. In various embodiments, the transition section may be a step, a chamfer, a curved profile, or a combination of these configurations.

[0013] The widened portions 110a, 110b may narrow the groove 140 between the widened portions 110a, 110b of the refining bars 100a, 100b at the entrance to the refining zone, thereby limiting the size of particles that enter the groove 140. Because the groove 140 widens between the narrowed portions 120a, 120b of the widened refining bars 100a, 100b at the entrance to the refining zone, particles large enough to pass between the widened portions 110a, 110b of the refining bars 100a, 100b at the entrance to the refining zone are unlikely to be trapped as they travel along the groove 140. The widened portions 110a, 110b of the refining bars 100a, 100b may include sloped portions 150a, 150b or other structures configured to divert larger particles that cannot pass through the entrance toward the refining gap between the refiner plates.

[0014] Figure 2 illustrates an example of a refining bar pattern 200 at the entrance 210 of a refiner plate to a refining zone 220, according to some embodiments of the present disclosure. As shown in Figure 2, refining bars 250a, 250b can include narrow sections 255a, 255b and widened sections 260a, 260b connected by transition sections 265a, 265b. The widened sections 260a, 260b can be located at the entrance 210 of the refining zone 220 and can be wider than the narrow sections 255a, 255b in the circumferential direction of the refiner plate or refiner plate segment. The widened sections 260a, 260b of refining bars 250a, 250b can be configured to narrow grooves 270 at the entrance 210 of the refining zone 220, thereby restricting the particle size entering the grooves 270. The narrow section 255 of the refining bar 250 may extend from the transition section 265 substantially the entire length of the remainder of the refining bar 250 .

[0015] The width of the widened portions 260a, 260b of the refining bars 250a, 250b may be approximately 0.2 to 1.5 mm wider than the width of the narrowed portions 255a, 255b of the refining bars 250a, 250b. The widened portions 260a, 260b of the refining bars 250a, 250b may narrow the groove 270 at the entrance 210 of the refining zone 220 by 5 to 30% of the groove width between the narrowed portions 255a, 255b of the refining bars 250a, 250b.

[0016] The refining bar configuration of the present disclosure results in a narrow groove 270 between the widened portions 260 of adjacent refining bars 250 at the entrance 210 of the refining zone 220, and a wide groove 275 that is wider than the narrow groove 270 and extends from the transition portion 265 for substantially the entire remainder of the length of the adjacent refining bar 250. In some embodiments, all refining bars may have a widened portion that narrows the groove between the widened portions of adjacent refining bars at the entrance of the refining zone. In some embodiments, less than all refining bars may have a widened portion that narrows the groove between the widened portion and an adjacent refining bar that does not have a widened portion at the entrance of the refining zone. In some embodiments, all refining zones may include refining bars with widened portions at the entrance. In some embodiments, less than all refining zones may include refining bars with widened portions at the entrance.

[0017] Particles larger than the narrow grooves 270 between the widened sections 260 of the refining bars 250 may be diverted by the sloped or chamfered sections 280 of the widened sections 260 toward the refining gap between the opposing refiner plates, where they are separated into smaller particles.

[0018] The transition section of a refining bar may be formed in a variety of different shapes. Figures 3A-3F illustrate example refining bar transition shapes for providing a narrowed groove at the entrance to a refining zone, according to some embodiments of the present disclosure, along with side views of the corresponding refining bar. Referring to Figure 3A, a refining bar 310 may have a widened section 312 that narrows to a narrowed section 314 via a transition section 316 that has chamfers on both sides of the refining bar 310. Figure 3B shows an example of a refining bar 320 in which a transition section 326 between the widened section 322 and the narrowed section 324 has curved sections on both sides of the refining bar 320.

[0019] The refining bar 330 shown in Figure 3C can include a transition 336 between the widened section 332 and the narrowed section 334, with a step on both sides of the refining bar 330. Figure 3D shows a transition 346 between the widened section 342 and the narrowed section 344 of a refining bar 340, with a chamfer 348 on only one side of the refining bar.

[0020] The refining bar 350 shown in Figure 3E may include a radially extended portion of the widened section 352 and chamfers on both sides of the refining bar 340, and may include a transition section 356 where the widened section 352 narrows to the narrowed section 354. Figure 3F shows a refining bar 360 with a chamfer on one side of the refining bar and a curved section 368 on the other side, where the refining bar 360 narrows from the widened section 362 to the narrowed section 364. It should be understood that other transition section configurations where the entrance portion of the refining bar widens may be used without departing from the scope of this disclosure.

[0021] In some embodiments, the transition portion of the refining bar may be located at a chamfer or slope facing the inlet of the refiner plate. Figures 3G and 3H illustrate examples of the shape of the transition portion of the refining bar chamfer at the inlet, according to some embodiments of the present disclosure. Referring to Figure 3G, the chamfer may be a slope 372 that rises diagonally from base 374 to the top surface of refining bar 376. The bottom of slope 372 may extend linearly along base 374 of refiner plate segment 370 for a length "b." Transition portion 378 may begin at chamfer 372, a linear distance "a" along base 374 of refiner plate segment 370, and terminate at, short of, or beyond the top surface of refining bar 376. The ratio of linear distance "a" to chamfer length "b" may be greater than 0.5 (e.g., a / b > 0.5).

[0022] In Figure 3H, groove width "a" at the entrance to the refining zone can be less than or equal to linear distance "b" along base 384 of refiner plate segment 380 from the beginning of transition 388 of chamfer 382 to the end of chamfer 382 on the top surface of refining bar 386 (e.g., b < a). Other configurations of chamfers and / or transitions may be provided without departing from the scope of this disclosure.

[0023] 3J illustrates an example of a refining bar providing a narrowed groove at the entrance to the refining zone and widening in width along the length of the refining bar, according to some embodiments of the present disclosure. As shown in FIG. 3J, adjacent refining bars 392a, 392b may provide a narrow groove having a width "a" at the entrance to the refining zone and a wide groove having a width "b" at the end of the transition zone 394a, 394b (e.g., b > a). Proceeding along the length of the groove, the groove may narrow to a width "c" that is greater than width "a" but less than width "b" (e.g., b > c > a).

[0024] In some embodiments, the refining bars facing the inlet of the refiner plates may have a chamfer or bevel. The chamfer or bevel can redirect material fed toward the restrictive entrance of the refining zone so that it flows toward the refining gap between opposing refining disks. Figures 4A-4D show examples of refining bar chamfers or bevels according to some embodiments of the present disclosure. Referring to Figure 4A, the refining bar 415 may be angled at approximately 90° relative to the base 417 (e.g., without a chamfer or bevel). Particles too large to enter the inlet move into the refining gap between the refiner plates, where they can be separated into smaller particles.

[0025] Figure 4B shows a ramp 420 that rises sharply from the base 427 to the top surface of the refining bar 425. Particles too large to enter the inlet can flow up the ramp 420 into the refining gap between the refiner plates. Figure 4C shows an arcuate chamfer 430 between the base 437 and the top surface of the refining bar 435. Figure 4D shows a chamfer 440 that extends obliquely from the top surface of the refining bar 445 but is truncated before reaching the base 447.

[0026] The chamfers or bevels can reduce the possibility of particle trapping at the entrance to a given refining zone, which can restrict flow into the grooves between the refining bars and through the refiner. Other configurations of chamfers or bevels may be provided without departing from the scope of this disclosure.

[0027] Widening the refining bars at fixed radial locations reduces the volume available at a given radial location, restricting flow. According to aspects of the present disclosure, the radial locations of the refining zone inlets relative to the center of the refining disk may be distributed or angled relative to an arc that radially intersects the refiner plate segment. The refining zone inlets may be arranged in a sawtooth pattern, a chevron pattern, a dotted transition pattern, or the like. The refining bar ends may be arranged along curves, straight lines, or a combination thereof.

[0028] 5A-5C show examples of refining bar arrangements to provide narrowed grooves at the refining zone inlet of a refiner plate according to some embodiments of the present disclosure. In some embodiments, the refiner plate may be a unitary ring or a unitary cone. In some embodiments, multiple refiner plate segments may form a ring- or cone-shaped refiner plate. FIG. 5A shows a non-distributed refining zone inlet arrangement. A non-distributed refining zone inlet arrangement can cause a pinch point at maximum flow rate. The pinch point can be resolved by arranging the refining zone inlet to have a distributed transition. The transition of a distributed refining zone inlet may be configured in a shape other than a smooth arc. Non-limiting examples of distributed refining zone inlet transitions include a Z-shaped transition in the refining zone inlet 515 of the refiner plate segment 510 as shown in Figure 5B, or a chevron-shaped transition in the refining zone inlet 525 of the refiner plate segment 520 as shown in Figure 5C. As shown in Figures 5B and 5C, adjacent refining bars may have different radial distances from the inner peripheries 512, 522 of the refiner segments 510, 520 to the inner ends 517, 527 of the adjacent refining bars. Other distributed refining zone inlet transition shapes may also be used without departing from the scope of this disclosure.

[0029] Alternatively, the lengths of individual refining bars at the refining zone entrance may be alternating to avoid radial flow restriction. Figure 6 shows an example of refining bars with alternating lengths to provide narrowed channels at the refining zone entrance, according to some embodiments of the present disclosure. Referring to Figure 6, refining bars 610 and 620 may have a first length, and refining bars 630 and 640 may have a shorter length than refining bars 610 and 620. Refining bar 650 may have a third length that is shorter than bars 610 and 620 but longer than refining bars 630 and 640. As shown in the examples of Figures 5B and 5C, adjacent refining bars may have different radial distances from the inner circumference of the refiner segment to the inner ends of the adjacent refining bars.

[0030] As shown in Figure 6, a refining bar 610 having a first length may be adjacent to a refining bar 630 having a second length, which may be adjacent to a refining bar 650 having a third length, which may be adjacent to a refining bar 640 having a second length, which may be adjacent to a refining bar 640 having a first length. By alternating the positions of the refining bars of the first, second, and third lengths as shown in Figure 6, pinch points (e.g., flow restrictions) at the entrance to the refining zone may be avoided. A distributed arrangement of refining bars of two or more lengths may alleviate flow restrictions at the entrance to the refining zone.

[0031] Widening the refining bars circumferentially around a refiner plate or refiner plate segment at the entrance to a refining zone can be applied when the beginning of one refining zone is not connected to the previous refining zone, but can also be applied when two or more refining zones are connected via multiple bars, dams, links, or any other means. Figure 7 shows an example of a refining bar 725 for providing a narrowed groove at the entrance to an outer refining zone that is not connected to an inner refining zone, according to some embodiments of the present disclosure.

[0032] Referring to Figure 7, refining bars 710 in inner refining zone 705 are not connected to outer refining zone 720. Refining bars 725 at the entrance to refining zone 720 may include widened sections 727 that restrict particles entering outer refining zone 720. The size of particles accepted by outer refining zone 720 may be determined by the spacing between widened sections 727 of widened refining bars 725. Particles larger than the spacing between widened sections 727 may be diverted by sloped or chamfered sections of widened sections 727 (see, e.g., Figures 4A-4D) toward the refining gap between opposing refiner plates.

[0033] Figure 8 illustrates an example of a refining bar 825 for providing a narrowed groove at the entrance to the outer refining zone, with a portion of the refining bar 825 connected to the inner refining zone, according to some embodiments of the present disclosure. As shown in Figure 8, refining bars 810a and 810b can connect the inner refining zone 805 and the outer refining zone 820. The refining bar 825 is disposed within the outer refining zone 820. The refining bar 825 can include an expanded portion 827 at the entrance to the outer refining zone 820. The size of particles accepted by the outer refining zone 820 can be determined by the spacing between the expanded portion 827 of the expanded refining bar 825 and the sides 812a, 812b of the refining bars 810a and 810b. Particles larger than the spacing between the widened portions 827 can be diverted by the sloped or chamfered portions of the widened portions 827 (see, for example, Figures 4A-4D) to flow toward the refining gap between the opposing refiner plates.

[0034] It should be understood that the examples of Figures 7 and 8 are non-limiting examples and that other implementations may be provided without departing from the scope of the present disclosure.

[0035] In some embodiments, a restrictive refining zone entrance may be created by alternating standard refining bars with widened refining bars. FIG. 9 illustrates an example of alternating refining bars to create narrowed grooves at the refining zone entrance, according to some embodiments of the present disclosure. Referring to FIG. 9, standard refining bars 910a-c may be alternated with widened refining bars 920a, 920b at the entrance to the refining zone. This alternating refining bar configuration may narrow grooves 930a-d at the entrance to the refining zone, limiting the size of particles entering grooves 930a-d. By limiting the size of particles entering grooves 930a-d at the entrance, the likelihood of particles becoming trapped and clogging grooves 930a-d is reduced. Larger particles can be diverted by the sloped or chamfered portions of the standard refining bars 910a-c and the widened refining bars 920a, 920b (see, for example, Figures 4A-4D) toward and into the refining gap between opposing refiner plates.

[0036] The accompanying claims and their equivalents are intended to cover such forms or modifications as fall within the scope and spirit of protection. For example, the exemplary apparatus, methods, and systems disclosed herein may be applied to single-disc, double-disc, counter-rotating, flat, conical, cylindrical, or other types of purification apparatus operating at low, medium, or high concentrations. Additionally, the features and attributes of specific exemplary embodiments disclosed above may be combined in various ways to form additional embodiments, all of which are within the scope of the present disclosure.

[0037] While the present disclosure provides certain exemplary embodiments and applications, other embodiments apparent to those skilled in the art, including embodiments that do not provide all of the features and advantages described herein, are also within the scope of the present disclosure. Accordingly, the scope of the present disclosure is intended to be defined solely by reference to the appended claims.

Claims

1. A refiner plate including at least one refining zone including a first plurality of refining bars and a plurality of grooves, at least one groove of the plurality of grooves has a first width between adjacent refining bars of the first plurality of refining bars at an entrance to the at least one refining zone that is narrower than a second width along the remainder of the at least one groove; A refiner plate, wherein at least one of the adjacent refining bars of the first plurality of refining bars has a widened portion that widens in the circumferential direction of the refiner plate at an entrance portion of the at least one refining zone.

2. 2. The refiner plate of claim 1, wherein the at least one of the adjacent refining bars has a third width at the entrance portion of the at least one refining zone that is wider than a fourth width of the remainder of the at least one of the adjacent refining bars.

3. 3. The refiner plate of claim 2, wherein the at least one adjacent refining bar includes a transition portion configured such that a width of the at least one adjacent refining bar transitions between the third width of the at least one adjacent refining bar and the fourth width of the remainder of the at least one adjacent refining bar.

4. The refiner plate of claim 3 , wherein the at least one adjacent refining bar has a transition on at least one side that includes one of a chamfer, a curved portion, or a stepped portion.

5. The refiner plate of claim 3 , wherein the at least one adjacent refining bar has a transition on each side that includes one or a combination of a chamfer, a curved portion, or a step.

6. The refiner plate of claim 3 , wherein the transition section includes a radially extended portion of the widened section and a chamfer on each side of the at least one refining bar.

7. The refiner plate of claim 1 , wherein the widened portion of the at least one adjacent refining bar includes at least a portion that slopes obliquely up from a base toward an upper surface of the at least one refining bar.

8. the at least one refining zone includes a second plurality of refining bars, each refining bar of the second plurality of refining bars having a third width of the widened portion at the entrance portion of the at least one refining zone that is greater than a fourth width of each of the remainder of the second plurality of refining bars; 2. The refiner plate of claim 1, wherein the widened portion has a first width at the entrance portion of the at least one refining zone that is greater than a second width of the remainder of the at least one refining bar in the circumferential direction of the refiner plate.

9. The refiner plate of claim 1 , wherein the inlet portion of the at least one refining zone includes a refining zone inlet arranged in a distributed transition.

10. 2. The refiner plate of claim 1, wherein the widened portions of the first plurality of refining bars are radially staggered in the entrance portion of the at least one refining zone so that adjacent refining bars have different radial distances from the inner circumference of the refiner plate to the inner ends of the adjacent refining bars.

11. The refiner plate of claim 1 , wherein the refiner plate is a unitary ring or a unitary cone.

12. A refiner plate including a plurality of refiner plate segments, each refiner plate segment having at least one refining zone including a first plurality of refining bars and a plurality of grooves; at least one groove of the plurality of grooves has a first width between adjacent refining bars of the first plurality of refining bars at an entrance to the at least one refining zone that is narrower than a second width along the remainder of the at least one groove; A refiner plate, wherein at least one of the adjacent refining bars of the first plurality of refining bars has a widened portion that widens in the circumferential direction of the refiner plate at an entrance portion of the at least one refining zone.

13. 13. The refiner plate of claim 12, wherein the at least one of the adjacent refining bars has a third width at the entrance portion of the at least one refining zone that is wider than a fourth width of the remainder of the at least one of the adjacent refining bars.

14. 14. The refiner plate of claim 13, wherein the at least one adjacent refining bar includes a transition portion configured such that a width of the at least one adjacent refining bar transitions between the third width of the at least one adjacent refining bar and the fourth width of the remainder of the at least one adjacent refining bar.

15. 15. The refiner plate of claim 14, wherein the at least one adjacent refining bar has a transition on at least one side that includes one of a chamfer, a curved portion, or a stepped portion.

16. 15. The refiner plate of claim 14, wherein the at least one adjacent refining bar has a transition on each side that includes one or a combination of a chamfer, a curved portion, or a step.

17. The refiner plate of claim 14 , wherein the transition section includes a radially extended portion of a widened section and a chamfer on each side of the at least one refining bar.

18. 13. The refiner plate of claim 12, wherein the widened portion of the at least one adjacent refining bar includes at least a portion that slopes obliquely up from a base toward an upper surface of the at least one refining bar.

19. 13. The refiner plate of claim 12, wherein the at least one refining zone includes a second plurality of refining bars, each refining bar of the second plurality of refining bars having a third width of the widened portion at the entrance portion of the at least one refining zone that is greater than a fourth width of each of the remainder of the second plurality of refining bars.

20. 20. The refiner plate of claim 19, wherein the widened portions of the second plurality of refining bars are radially staggered or distributed in the entrance portion of the at least one refining zone.

21. The refiner plate of claim 12 , wherein the inlet portion of the at least one refining zone includes a refining zone inlet arranged in a distributed transition.

22. The refiner plate of claim 12 , wherein the plurality of refiner plate segments form a ring or a cone.

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