Blade segments for refiners

Abstract

A blade segment for a refiner (1) for refining fibrous material. The blade segment includes a first edge (20) and a second edge (21), a first side edge (22) and a second side edge (23) opposite the first side edge (22), blade bars (28, 27a, 27b) on a forward surface (25) of the blade segment and blade grooves (28, 28a, 28b) between the blade bars. The blade segment further includes at least one opening (14, 15) in at least one side edge (22, 23) extending through the entire thickness of the blade segment body (24), and at least one feed groove (29) on the refining surface extending from the opening and intersecting the blade bar and the blade groove for feeding material to be refined across the refining surface. The blade bars of the blade segment are interlaced with the feed groove.

Description

Technical Field

[0001] The present invention relates to a refiner for purifying fibrous materials, and particularly to a blade segment for a refiner for refining fibrous materials.

Background Art

[0002] Refiners used for manufacturing mechanical pulp or for refining at any low consistency typically form a refining gap or chamber between two refining elements that rotate relative to each other, i.e., one or both of them rotate, and include two opposing refining elements. The refining elements include a refining surface with blade bars and blade grooves therebetween. The blade bars are intended to defibre and refine the material to be refined, and the blade grooves are intended to carry the material to be refined forward along the refining surface. The refining surface of the refining element is typically formed by several blade segments fixed to the body of each refining element. Thus, the complete refining surface of the refining element is formed by the refining surfaces of several blade segments fixed adjacent to each other within the refining element.

[0003] One type of refiner is a so-called through-fed or through-flow refiner in which the material to be refined is supplied not only from one end to the other end of the refiner but also from an intermediate portion, i.e., through the refining element into the refining gap. This type of refiner is disclosed in Patent Document 1, and the refining element includes openings that provide an opening area of 5 to 70% of its refining region. Another example is disclosed in Patent Document 2, where the openings are indents at the side edges of the refining element, and the material flow is enhanced by a feed groove.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The object of the present invention is to provide a novel blade element for a refiner for purifying fibrous materials, and a novel refiner for purifying fibrous materials. [Means for solving the problem]

[0005] The invention is characterized by the configuration of independent terms.

[0006] This invention is based on the idea of ​​interlacing the blade bars of the blade segments in a feeding groove.

[0007] Interlacing the blade bars in the feed groove provides a strong blade bar configuration in which the interlaced blade bars support each other in the feed groove, thereby preventing buckling of the blade bars in the feed groove.

[0008] Several embodiments of the present invention are disclosed in the dependent claims.

[0009] In the following, the present invention will be described in more detail by preferred embodiments with reference to the accompanying drawings. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic general side cross-section of a conical refiner.

[0011] [Figure 2] This is a schematic top view perspective of a portion of a set of adjacent rotor blade segments.

[0012] [Figure 3] This is a schematic top view perspective of a rotor blade segment.

[0013] [Figure 4] This is a schematic top view perspective of the feed groove within the rotor blade segment.

[0014] [Figure 5] This is a schematic top view of another blade segment.

[0015] [Figure 6a] This diagram schematically shows the interlacing of the blade bars at the first end of the feed groove.

[0016] [Figure 6b] This diagram schematically shows the interlacing of the blade bars at the second end of the feed groove. [Modes for carrying out the invention]

[0017] For clarity, the figures illustrate several embodiments of the present invention in a simplified manner. Similar reference numerals identify similar elements in the figures.

[0018] Figure 1 is a schematic general side cross-sectional view of the general structure of a refiner 1, which may be used to refine fibrous materials such as wood materials containing lignocellulose and other fibrous materials suitable for producing paper or cardboard, for example. The refiner 1 shown in Figure 1 is of a conical type, but disc refiners, conical disc refiners, and cylindrical refiners can be used in the same manner as in this example. Generally, a refiner includes at least two substantially opposing refining elements, at least one of which is rotatable, and a refining chamber formed between each pair of substantially opposing refining elements. A refiner having only one rotatable refining element is described below.

[0019] The refiner 1 in FIG. 1 includes a frame 2 and a stationary fixed refining element 3 supported by the frame 2, i.e., a stator 3. The stator 3 includes two or more stator blade segments 4, each of which includes a blade bar and a blade groove therebetween. The blade bar and the blade groove in each stator blade segment 4 form the refining surface 5 of the respective blade segment 4, whereby the refining surface 5 of each stator blade segment 4 provides a part of the refining surface of the stator 3. The complete refining surface of the stator 3 is formed by the refining surfaces 5 of the required number of blade segments 4 that are fixed adjacent to each other within the stator 3 such that a complete refining surface 5 extending across the entire circumference of the stator 3 is provided. For clarity, both the refining surface of each single stator blade segment 4 and the complete refining surface of the stator 3 are denoted by the same reference numeral 5 in this specification.

[0020] The refiner 1 further includes a rotatable refining element 6 of the refiner 1, i.e., a rotor 6. The rotor 6 includes a hub 7. The rotor 6 further includes two or more rotor blade segments 8 supported by the hub 7, each rotor blade segment 8 including a blade bar and a blade groove therebetween. The blade bar and the blade groove in each rotor blade segment 8 form the refining surface 9 of the respective rotor blade segment 8, whereby the refining surface 9 of each rotor blade segment 8 provides a part of the refining surface of the rotor 6. The complete refining surface 9 of the rotor 6 is formed by the refining surfaces 9 of the required number of blade segments 8 that are fixed adjacent to each other within the rotor 6 such that a complete refining surface 9 extending across the entire circumference of the rotor 6 is provided. For clarity, both the refining surface of each single rotor blade segment 8 and the complete refining surface of the rotor 6 are denoted by the same reference numeral 9 in this specification.

[0021] The hub 7 of the rotor 6 is connected, for example, by a shaft 11 to a drive motor 10 such that the rotor 6 can be rotated relative to the stator 3 in the direction of the arrow RD, and thus the arrow RD indicates the intended direction of rotation RD of the rotor 6.

[0022] The refiner 1 may also include a loading device, not shown in FIG. 1 for clarity. The loading device can be used to move the rotor 6 attached to the shaft 11 back and forth, as schematically indicated by arrow A, in order to adjust the refining gap 12 between the stator 3 and the rotor 6, i.e., the size of the refining chamber 12, and the fiber material is actually refined.

[0023] The fiber material to be refined is supplied to the refiner 1 via the feed channel 13 in the manner indicated by arrow F. In one embodiment, most of the fiber material supplied to the refiner 1 proceeds into the refining chamber 12 through the opening 14 formed in the rotor blade segment 8 in the manner schematically indicated by arrow P, and the fiber material will be refined in the refining chamber 12. Further, most of the already refined fiber material is then discharged into the intermediate space 16 between the frame 2 and the stator 3 of the refiner 1 through the opening 15 formed in the stator blade segment 4, and the refined material is removed from the refiner 1 via the discharge channel 17 as schematically indicated by arrow D.

[0024] Since the space between the rotor 6 and the frame 2 of the refiner 1 in FIG. 1 is not completely closed, a part of the fiber material to be supplied to the refiner 1 may be transferred to the refining chamber 12 from the right end of the refining chamber 12, i.e., from the first end 18 or inner end 18 of the refiner 1 having a smaller diameter, as seen in FIG. 1. Correspondingly, a part of the already refined material may exit the refining chamber 12 from the left end of the refining chamber 12, i.e., from the second end 19 or outer end 19 of the refiner 1 having a larger diameter, as seen in FIG. 1, from where a connection is provided to the intermediate space 16.

[0025] In the embodiment of refiner 1 shown in Figure 1, only one feed channel 13 is provided, which is located at the first end 18 of refiner 1 having a smaller diameter. Actual implementations of the refiner may also include a second feed channel located at the second end 19 of refiner 1 having a larger diameter, thereby allowing the discharge channel 17 of refiner 1 to be located, for example, somewhere between the first end 18 and the second end 19 of refiner 1. Hereinafter, the reference symbol 18 and the terms first end 18 or inner end 18 may refer to both the first end 18 or inner end 18 of refiner 1 having a smaller diameter and the first end 18 or inner end 18 of the refining element 3, 6 or refining chamber 12 having a smaller diameter. Accordingly, the reference symbol 19 and the terms second end 19 or outer end 19 may refer to both the second end 19 or outer end 19 of refiner 1 having a larger diameter and the second end 19 or outer end 19 of the refining element 3, 6 or refining chamber 12 having a larger diameter.

[0026] It is emphasized that, in addition to the conical refiners disclosed above, the blade segments of the solutions described herein may also be applied to other types of conical refiners. In addition to conical refiners, the blade segments of the solutions described herein are also applicable to disc refiners and cylindrical refiners, as well as refiners that include both conical and disc portions.

[0027] Figure 2 is a schematic top perspective view of a portion of a set of adjacent rotor blade segments 8, and Figure 3 is a schematic top perspective view of a rotor blade segment 8 applicable to be used to form a portion of the refined surface 9 of the rotor 6. Hereinafter, the blade segment structure will be discussed in more detail with respect to the rotor blade segment 8, although the structure of the stator blade segment 4 is substantially similar unless otherwise disclosed.

[0028] The blade segment 8 includes an inner end edge 20 or first end edge 20 which is directed toward the inner end 18 of the rotor 6 having a smaller diameter. The blade segment 8 further includes an outer end edge 21 or second end edge 21 which is directed toward the outer end 19 of the rotor 6 having a larger diameter. In conical and cylindrical refiners, the inner end edge of the blade segment provides the axial inner end of the blade segment, the outer end edge of the blade segment provides the axial outer end of the blade segment, the direction from the axial inner end to the axial outer end provides the longitudinal axis of the blade segment, which is schematically shown in Figure 3 by arrow LA. In disc refiners, the inner end edge of the blade segment provides the radial inner end of the blade segment, the outer end edge of the blade segment therefore provides the radial outer end of the blade segment, and the direction from the radial inner end to the radial outer end provides the longitudinal axis of the blade segment.

[0029] The blade segment 8 further includes a first side edge 22 or leading side edge 22 that extends from the inner edge 20 of the blade segment 8 to the outer edge 21 of the blade segment 8, providing the side edge of the blade segment 8 that first intersects with the edge of the counter blade segment, and thus it is oriented toward the intended rotation direction RD of the rotor 6. The blade segment 8 further includes a second side edge 23 or trailing side edge 23 that opposes the first side edge 22 and extends from the inner edge 20 of the blade segment 8 to the outer edge 21 of the blade segment 21, providing the side edge of the blade segment 8 that last intersects with the edge of the counter blade segment, and thus it is oriented toward the direction opposite to the intended rotation direction RD of the rotor 6. The inner edge 20 and the outer edge 21, together with the first side edge 22 and the second side edge 23, define the periphery of the blade segment 8.

[0030] The blade segment 8 includes a body 24 having a front surface 25 which is oriented toward the refining chamber 12 of the refiner 1, and a guided background surface 26 which is oriented toward the hub 7 of the rotor 6. The front surface 25 of the blade segment body 24 includes a blade bar 27 and a blade groove 28 which together provide the refining surface 9 of the blade segment 8. The blade bar 27 is intended to defibre and refine the material to be refined, and the blade groove 28 is intended to carry the material to be refined forward along the refining surface 9.

[0031] The blade segment 8 further includes fastening holes 31, 32 intended to receive fastening means such as bolts for fastening the blade segment 8 directly to the hub 7 of the rotor 6 or to any support structure, or via support means such as a retaining ring 33. The blade segment 8 further includes extensions or shoulder portions 34, 35, 36, 37 at its corners, and the blade segment 8 laterally contacts its adjacent blade segment 8 at the extensions or shoulder portions, thereby potentially supporting each other.

[0032] Since the blade segments of the solutions disclosed herein are used in a through-feed refiner, the blade segments are provided with openings to allow pulp feeding / discharging through the refined surfaces of the stator and / or rotor. Herein, the openings are located on at least one side edge of the blade segment in the central portion of the longitudinal axis of the blade segment.

[0033] In the blade segment 8 of Figure 2, there is a discontinuously extending slit on the first side edge 22 of the blade segment 8 between a shoulder portion 34 on the first end edge 20 of the blade segment 8 on the side surface of the first side edge 22 of the blade segment 8 and a shoulder portion 36 on the second end edge 21 of the blade segment 8 on the side surface of the first side edge 22 of the blade segment 8. This continuous, uninterrupted slit or bay is formed by two substantially straight long edge portions 22a, 22b connected by a bevel 22c, and the orientation of the long edge portions 22a, 22b is such that at the first side edge 22, they deviate from the direction of the longitudinal axis LA of the blade segment 8 toward the center of the blade segment 8, i.e., they deviate in the same direction with respect to the longitudinal axis LA. Next, the bevel 22c is positioned at the first side edge 22 so as to deviate away from the center of the blade segment 8 from the direction of the longitudinal axis LA of the blade segment 8, i.e., deviating in the opposite direction to the longitudinal axis LA of the blade segment 8 than the long side edge portions 22a, 22c. Unlike those shown in Figures 2 and 3, one or more shoulder members may be present along the side edge where the slit is interrupted, thus providing indentations between two shoulder members. For example, the bevel 22c may extend to contact an adjacent segment.

[0034] In other words, the slit or bay on the first side edge 22 of the blade segment 8 is positioned such that the first side edge 22 does not form a perfectly straight line between the shoulder members 34, 36 on the inner edge 20 and the outer edge 21, but forms a longitudinal slit or bay with a gently zigzag or lightning-shaped edge. This slit or bay on the blade segment 8 provides an opening 14 on the first side edge 22 of the blade segment 8. This opening 14 extends from the front surface 25 of the blade segment 24 to the rear or background surface 26 of the blade segment 24, and thus extends through the entire thickness of the blade segment 8 or the blade segment body 24.

[0035] Furthermore, according to one embodiment of the blade segment 8, as can be seen in Figure 2, the blade segment 8 includes substantially similar openings 14 on both sides of the blade segment 8, so that the openings on the second side edge 23 also extend from the second side edge 23 toward the opposite first side edge 22, so that the second side edge 23 does not form a perfectly straight line between the inner edge 20 and the outer edge 21.

[0036] When assembling the blade segments adjacent to each other to form the polished surfaces 5 and 9 of the stator 3 or rotor 6, continuous or discontinuous longitudinal slit-shaped openings are provided between adjacent blade segments.

[0037] Figure 5 is a schematic top view of another blade segment 8. In the blade segment 8 of Figure 5, the first side edge 22 of the blade segment 8 includes a number of openings 14, each opening having the form of a recess extending from the first side edge 22 toward the opposite second side edge 23. In other words, the openings 14 are present in the first side edge 22 of the blade segment 8 such that the first side edge 22 does not form a perfectly straight line between the inner edge 20 and the outer edge 21. The openings 14 extend from the front surface 25 of the blade segment body 24 to the rear or background surface 26 of the blade segment body 24, and thus the openings 14 extend through the entire thickness of the blade segment 8 or the blade segment body 24. Furthermore, the blade segment 8 may include one or more similar openings 14, i.e., recesses, extending from the second side edge 23 toward the opposite first side edge 22 such that the second side edge 23 also does not form a perfectly straight line between the inner edge 20 and the outer edge 21.

[0038] The blade segment 8 in Figures 3 and 5, or the refined surface 9 of the blade segment 8 in Figures 3 and 5, further includes a feed groove 29. The feed groove 29 is positioned so as to extend from an opening 14 located on the first side edge 22 of the blade segment 8 toward at least one other edge of the blade segment 8 toward the second side edge 23 of the blade segment 8, in the embodiments of Figures 3 and 5, so as to intersect the blade bar 28 and the blade groove 29. The feed groove 29 has a first end 29a located in the opening 14 and a second end 29b facing outward when viewed from the opening 14. The opening 14 and feed groove 29 located on the first side edge 22, i.e., the front side edge of the blade segment 8, form a flow connection where material to be refined and supplied from the side of the background surface 26 of the blade segment 8 toward the front surface 25 of the blade segment 8 through the opening 14 enters the feed groove 29 and flows along the feed groove 29 toward the central portion of the blade segment 8, thus supplying the material to be refined across the refined surface 9. At the same time, as the blade segment 8 rotates along the rotor 6, the force acting on the material flowing into the feed groove 29 pushes the material from the feed groove 29 into the blade groove 28 remaining between the blade bars 27, thus distributing the material to be refined toward the refined surface 9 of the blade segment 8.

[0039] The feeding or supply of material through the opening 14 on the side edge 22 of the blade segment 8 allows the material to flow directly onto the refined surface 9, at least partially along the circumferential direction of the refined surface 9, without the need to convert the flow of the supplied material from axial or radial to rotational motion at least partially along the circumferential direction of the refined surface, when the feeding or supply of material is performed in a refiner where the feeding or supply of material is performed beyond the inner edge of the blade segment. This reduces the energy consumption of the refiner, for example, by avoiding features of the refinement operation that do not directly improve the efficiency of the refinement.

[0040] In the embodiments of Figures 2 and 3, the feed groove 29 has a first end 29a located in a slit or bay on the first side edge 22 of the blade segment 8, and a second end located in or near a slit or bay on the second side edge 23 of the blade segment 8, i.e., the opposite side edge 23 of the blade segment 8. Specifically, the first end 29a of the feed groove 29 is preferably located near the fixing ring, either immediately before or after the fixing ring to which the blade segment is to be assembled to its respective refining element. In the embodiments of Figures 2 and 3, the feed groove 29 enhances the flow of pulp on the refining surface, particularly near the region of the slit where the fixing ring would otherwise interrupt a continuous slit, preventing the pulp from freely reaching the refining surface and around the bolt holes. Similarly, if the slit is discontinuous and interrupted by a shoulder member, the first end 29a of the feed groove 29 is preferably located near the shoulder, and the feed groove 29 extends over the bolt holes.

[0041] To increase the strength of the structure of the refined surface 9 in the feed groove 29, the blade bars 27 are interlaced in the feed groove 29. Interlacing of the blade bars 27 in the feed groove 29 means, referring more specifically to the embodiment in Figure 4, that the blade bars 27 on one side of the feed groove 29 relative to the longitudinal axis LA of the blade segment 8 are positioned to extend into the blade groove 28 between the blade bars 27 on the opposite side of the feed groove 29 relative to the longitudinal axis LA of the blade segment 8, and vice versa.

[0042] One embodiment of the interlacing of the blade bars 27 is shown in more detail in Figure 4, which is a schematic top perspective view of the feed groove 29 within the rotor blade segment 8. A similar interlacing of the blade bars 27 may be applied to the blade segment of Figure 5, where the blade bars 27 are not depicted in the feed groove 29 in order to improve the visibility of the feed groove path.

[0043] To describe the embodiment in Figure 4 in more detail, it may be specified that, with respect to the feed groove 29 in the longitudinal direction of the blade segment 8, there is a first blade bar 27a extending toward the feed groove 29 from the direction of the inner edge 20 of the blade segment 8 to the feed groove 29, and a first blade groove 28a between the first blade bar 27a. Furthermore, with respect to the feed groove 29 in the longitudinal direction of the blade segment 8, it may be specified that there is a second blade bar 27b extending at least partially toward the outer edge 21 of the blade segment 8 from the direction of the feed groove 29, i.e., from the feed groove 29, and a second blade groove 28b between the second blade bar 27b.

[0044] The first blade bar 27a has an end 27a' that faces toward the outer edge 21 of the blade segment 8, i.e., toward the second blade bar 27b, and extends into the second blade groove 28b between two adjacent second blade bars 27b. The second blade bar 27b has an end 27b' that faces toward the inner edge 20 of the blade segment, i.e., toward the first blade bar 27a, and extends into the first blade groove 28a between two adjacent first blade bars 27a.

[0045] In the embodiment shown in Figure 4, the ends 27a' and 27b' of the blade bars 27a and 27b are linearly downward-sloping inclined surfaces arranged to be partially interlaced with each other, such that the downward-sloping inclined end 27a' of the first blade bar 27a partially extends into the second blade groove 28b between two adjacent or nearby second blade bars 27b and their downward-sloping inclined ends 27b', and correspondingly, the downward-sloping inclined end 27b' of the second blade bar 27b partially extends into the first blade groove 28a between two adjacent or nearby first blade bars 27a and their downward-sloping inclined ends 27a'. Therefore, in the embodiment shown in Figure 4, the oppositely oriented ends 27a', 27b' of the first blade bar 27a and the second blade bar 27b are arranged to extend by winding into oppositely positioned blade grooves 28a, 28b between the oppositely positioned blade bars 27a, 27b. The oppositely oriented linearly downward sloping ends 27a', 27b' of the first blade bar 27a and the second blade bar 27b form or provide an upwardly opening V-shaped feeding groove 29.

[0046] Deviating from the embodiment of Figure 4, instead of the ends 27a', 27b' of the blade bars 27a, 27b being linearly downward sloping surfaces, they can alternatively be convex or concave downward sloping surfaces, for example, to form or provide an upward-opening feed groove 29 between the oppositely oriented ends 27a', 27b of the first blade bar 27a and the second blade bar 27b. Thus, the feed groove 29 can have a U-shaped profile, or even a profile resembling the silhouette of a flying bird.

[0047] The interlaced blade bars 27, 27a, and 27b in the feed groove 29 support each other in the feed groove 29, thereby creating a stronger blade bar configuration that prevents buckling of the blade bars in the feed groove 29. In addition, the interlaced blade bars 27 in the feed groove 29 equalize the flow of material at the cutting edge of the blade segment 8 as the blade bars wear down. Furthermore, there is more blade bar material to wear in the feed groove 29, thereby improving the lifespan of the blade segments.

[0048] The material to be refined is supplied from the background surface 26 side of the blade segment 8 through an opening 14 to the feed groove 29 from the first end 29a of the feed groove 29. The material flows along the feed groove 29 from the first end 29a to the second end 29b of the feed groove 29, and at the same time, the material is distributed from the feed groove 29 into the blade groove 28 between the blade bars 27 and into the refinement chamber 12 between the stator 4 and rotor 8 blade elements on the blade bars 27.

[0049] According to one embodiment of the blade segment, the volume of the feed groove 29 is arranged to decrease along a path from a first end 29a to a second end 29b of the feed groove 29a. The decreasing volume of the feed groove 29 means the decreasing cross-sectional area of ​​the feed groove from the first end 29a to its second end 29. The decreasing volume of the feed groove 29 toward the second end causes the material to be refined and fed into the feed groove 29 to exit from the feed groove 29 into the blade grooves 28 between the blade bars 27, and into the refinement chamber 12 between the stator 4 and rotor 8 blade elements on the blade bars. The volume of the feed groove 29 may decrease substantially continuously or stepwise along the feed groove from the first end 29a to the second end 29b of the feed groove, from preceding blade bars to succeeding blade bars.

[0050] According to one embodiment of the blade segment, the reduced volume of the feed groove in the longitudinal direction of the feed groove is provided by arranging the angle of the downwardly decreasing inclined end of the interlaced blade bars with respect to the normal of the refined surface in the feed groove such that it decreases along the feed groove from a first end to a second end of the feed groove. In an example of the embodiment schematically shown in Figures 6a and 6b, Figure 6a schematically shows the interlacing of the blade bars 27a, 27b at the first end 29a of the feed groove 29, and Figure 6b schematically shows the interlacing of the blade bars 27a, 27b at the second end 29b of the feed groove 29.

[0051] Figures 6a and 6b show the first blade bar 27a and its end 27a', which are partially located behind the second blade bar 27b and its end 27b', as schematically indicated by the dashed lines in Figures 6a and 6b. Furthermore, Figures 6a and 6b show the normals 30 to the refined surfaces 9 of the blade segments 8 in the feed groove 29. Figure 6a shows angle a1 between the downward-sloping end 27a' of the first blade bar 27a and the normal 30, and angle b1 between the downward-sloping end 27b' of the second blade bar 27b at the first end 29a of the feed groove 29 and the normal 30. Figure 6b shows angle a2 between the downward-sloping end 27a' of the first blade bar 27a and the normal 30, and angle b2 between the downward-sloping end 27b' of the second blade bar 27b at the second end 29b of the feed groove 29 and the normal 30. From Figures 6a and 6b, it can be seen that the angle a1 between the downward-sloping end 27a' of the first blade bar 27a and the normal 30 at the first end 29a of the feed groove 29 is greater than the angle a2 between the downward-sloping end 27a' of the first blade bar 27a and the normal 30 at the second end 29b of the feed groove 29, and similarly, the angle b1 between the downward-sloping end 27b' of the second blade bar 27b and the normal 30 at the first end 29a of the feed groove 29 is greater than the angle b2 between the downward-sloping end 27b' of the second blade bar 27a and the normal 30 at the second end 29b of the feed groove 29. The cross-sectional area of ​​the feed groove 29, and thus the volume of the feed groove 29, decreases from the first end 29a of the feed groove 29 to the second end 29b of the feed groove 29.

[0052] The embodiments of the feed groove 29 in Figures 6a and 6b have the effect of slowing down the material flow from the feed groove, thereby preventing burst-like escape of material from the feed groove and enabling a substantially uniform flow of material from the feed groove. At the same time, it increases the total cutting edge length of the blade bar and, therefore, the total cutting edge length of the complete purified surface. These configurations, along with the blade segments of disclosure, i.e., blade segments having a material feed on their side edges and therefore a significant flow of material in the periphery direction, result in an improvement in the purification process of the material to be purified.

[0053] In the embodiments of Figures 6a and 6b, the normal 30 of the polished surface 9 of the blade segment 8 in the feed groove 29 forms the centerline of the feed groove 29 in such a manner that the angle between the downward-sloping end 27a' of the first blade bar 27a and the normal 30 and the angle between the downward-sloping end 27b' of the second blade bar 27b and the normal 30 are substantially equal along the feed groove 29. Thereafter, for example, angles a1 and b1 are substantially equal to each other, and angles a2 and b2 are substantially equal to each other. However, the angles between the downward-sloping end 27a' of the first blade bar 27a and the normal 30 and the angle between the downward-sloping end 27b' of the second blade bar 27b and the normal 30 may be set to be different from each other. In this case, for example, angles a1 and b1 may be set to be more or less different from each other, and angles a2 and b2 may be set to be more or less different from each other. In this case, the flow of material to be refined from the feed groove 29 may be controlled in different ways in different sections along the feed groove 29 by intentionally shaping the angle between the downward-sloping end 27a' of the first blade bar 27a and the normal 30, and the angle between the downward-sloping end 27b' of the second blade bar 27b and the normal 30 to be different in different sections along the feed groove 29.

[0054] In one embodiment of the blade segment, the vertical position of the plane of incidence at the downward-sloping end of the interlaced blade bar is positioned to be substantially constant along the feed groove. An example of the embodiment schematically shown in Figures 6a and 6b schematically shows the plane of incidence, schematically indicated by reference numeral PI, of the opposing downward-sloping ends 27a', 27b' of the interlaced blade bars 27a, 27b. The plane of incidence PI is positioned at a distance H from the top surface of the body 24 of the blade segment 8, i.e., the top surface of the body 24 of the blade segment 8 schematically indicated by the dashed line indicated by reference numeral 24'. When the distance H of the plane of incidence PI from the top surface 24' of the body 24 of the blade segment 8 is configured to be substantially constant along the feed groove 29, it is possible to avoid the plane of incidence PI becoming the top surface of the refined surface 9 of the blade segment 9 before the end of the operating life of the blade segment 8.

[0055] According to one embodiment of the blade segment, the feeding groove is positioned to intersect the blade bar and the blade groove at a certain angle. In this embodiment, the feeding groove 29 preferably intersects the blade bar 27 and the blade groove 28 at an angle of 90 to ±45 degrees. The effect of this embodiment is better distribution of the material to be purified from the feeding groove 29 to the blade groove 28 and to the upper surface of the blade bar 27, i.e., into the purification chamber 12.

[0056] According to one embodiment of the blade segment, the feeding groove is curved along its elongation direction. In this embodiment, the second end 29b of the feeding groove 29 is located along the longitudinal axis LA of the blade segment at a different position than the first end 29a of the feeding groove 29. In other words, the ends 29a and 29b of the feeding groove are not located at the same normal level with respect to the longitudinal axis LA, but the first end 29a may be located at one normal level, for example, closer to the first edge 20 of the blade segment 8, while the second end 29b may be located at another normal level, i.e., farther away from the first edge 20 of the blade segment 8. An advantageous effect of this embodiment is that the pulp flow is directed to portions of the refined surface 9 that do not coincide with recesses on the side edges 22 and 23 of the blade segment 8, or to areas of the refined surface 9 that are difficult to access for pulp flow, such as the area around the fastening holes of the blade segment 8.

[0057] As technology advances, it will be apparent to those skilled in the art that the concept of the present invention can be implemented in various ways. The present invention and its embodiments are not limited to the examples described above and may vary within the scope of the claims. [Prior art documents] [Patent Documents]

[0058] [Patent Document 1] European Patent No. 2326767B1 [Patent Document 2] European Patent No. 3401439B1

Claims

1. A blade segment for a refiner that purifies fibrous materials, The first edge and the second edge, A first side edge and a second side edge opposite to the first side edge, the first side edge and the second side edge extending between the first edge and the second edge, A refined surface including the blade bar on the front surface of the blade segment and the blade groove between the blade bar, At least one opening on at least one side edge, the opening extending through the entire thickness of the blade segment body, The refined surface includes at least one feeding groove extending from the opening and intersecting the blade bar and the blade groove for feeding the material to be refined across the refined surface, The blade bars of the blade segment are interlaced in the feeding groove, Blade segment.

2. The blade segment according to claim 1, characterized in that the opening is a continuous slit on the side edge between extensions located at the corners of the blade segment.

3. The blade segment according to claim 1, characterized in that the opening is a recess located on the side edge and extending toward the opposite side edge.

4. The blade segment according to claim 1, characterized in that the blade bars are interlaced at their ends which are oriented in opposite directions in the feeding groove.

5. The blade segment according to claim 4, wherein, in the opposite direction, the oriented interlaced end of the interlaced blade bar includes a downward-sloping end configured to form an upward-facing opening for the feed groove.

6. The blade segment according to claim 5, characterized in that the end of the interlaced blade bar is a linearly downward-sloping end configured to form an upward-opening V-shaped feeding groove.

7. The blade segment according to any one of claims 1 to 6, characterized in that the volume of the feeding groove decreases from the first end of the feeding groove to the second end of the feeding groove at the opening.

8. The blade segment according to claim 7, as dependent on claim 5 or 6, characterized in that the angle of the downward-sloping end of the blade bar with respect to the normal to the refined surface in the feeding groove decreases along the feeding groove from the first end of the feeding groove toward the second end of the feeding groove.

9. The blade segment according to claim 8, characterized in that the angle between the normal of the purified surface and the downward-sloping end of the blade bar on one side of the feeding groove is equal to the angle between the normal of the purified surface and the downward-sloping end of the blade bar on the opposite side of the feeding groove.

10. The blade segment according to any one of claims 5 to 9, characterized in that the vertical position of the plane of incidence of the interlaced downward-sloping end of the interlaced blade bar is substantially constant along the feed groove.

11. The blade segment according to any one of claims 1 to 10, characterized in that the feeding groove is configured to intersect the blade bar and the blade groove at a certain angle.

12. The blade segment according to claim 11, characterized in that the feeding groove is configured to intersect the blade bar and the blade groove at an angle of 90 degrees to ±45 degrees.

13. The blade segment according to any one of claims 1 to 12, characterized in that the feeding groove is curved along its extension direction.

14. A refiner for refining fibrous materials, A blade segment comprising at least one blade segment as described in any one of claims 1 to 13, Refiner.

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