Blade segments for fine grinding machines

Abstract

A blade segment (4, 8) of a refiner (1) for refining fibrous material. The blade segment comprises: a first end edge (20) and a second end edge (21) and a first side edge (22) and a second side edge (23), the second side edge being opposite the first side edge (22); and a refining surface (5, 9), the refining surface comprising teeth (27, 27a, 27b) and grooves (28, 28a, 28b) between the teeth on a front surface (25) of the blade segment. The blade segment further comprises at least one opening (14, 15) at at least one side edge (22, 23), the opening extending through the entire thickness of the blade segment body (24), and at least one feed groove (29) on the refining surface, the feed groove (29) extending from the opening and intersecting the teeth and the grooves for conveying material to be refined across the refining surface. The teeth (27, 27a, 27b) of the blade segments are staggered at the feed grooves.

Description

Technical Field

[0001] The present invention relates to a refiner for refining fibrous materials, and in particular to a blade segment (refining sheet) of a refiner for refining fibrous materials. Background Art

[0002] A refiner for refining fibrous material, such as a refiner for making mechanical pulp or a refiner used in any low-consistency refining, usually comprises two refining elements which are arranged opposite each other, form a refining gap or refining chamber between them and rotate relative to each other (i.e. one or both rotate). The refining elements comprise a refining surface provided with teeth for defibering and refining the material to be refined and with grooves between the teeth for conveying the material to be refined along the refining surface. The refining surface of a refining element is usually formed by several blade segments fixed to the body of the respective refining element. Thus, the complete refining surface of a refining element is formed by the refining surfaces of several blade segments fixed closely to each other in the refining element.

[0003] One type of refiner is a so-called through-feed or through-flow refiner, in which the material to be refined is fed into the refining gap not only from one end of the refiner towards the other end, but also from the middle (in other words, through the refining element(s)). A refiner of this type is disclosed in EP2326767B1, in which the refining elements comprise openings providing an open area of ​​5%-70% of their refining area. Another example is disclosed in EP3401439B1, in which the openings are notches on the side edges of the refining segments and the material flow is enhanced by feed grooves. Summary of the invention

[0004] It is an object of the present invention to provide a new blade segment for a refiner for refining fibrous material, and a new refiner for refining fibrous material.

[0005] The invention is characterized by the features of the independent claims.

[0006] The invention is based on the idea of ​​staggering the teeth of the blade segments at the feed grooves.

[0007] The staggering of the teeth at the feed groove provides a strong tooth configuration at the feed groove, wherein the staggered teeth support each other, thereby preventing buckling of the teeth at the feed groove.

[0008] Some embodiments of the invention are disclosed in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention will be described in more detail below by means of preferred embodiments with reference to the accompanying drawings, in which:

[0010] Figure 1 is a schematic overall side view of a conical refiner shown in cross section;

[0011] Figure 2 is a schematic upper oblique view of a portion of a group of adjacent rotor blade segments;

[0012] Figure 3 is a schematic upper oblique view of a rotor blade segment;

[0013] Figure 4 is a schematic upper oblique view of a feed groove in a rotor blade segment;

[0014] Figure 5 is a schematic upper plan view of another blade segment;

[0015] Figure 6a schematically shows the staggering of the teeth at the first end of the feed groove, and

[0016] Figure 6b The staggering of the teeth at the second end of the feed groove is schematically shown.

[0017] For the sake of clarity, the accompanying drawings show some embodiments of the present invention in a simplified manner.In the accompanying drawings, similar reference numerals represent similar elements. DETAILED DESCRIPTION

[0018] Figure 1 is a schematic overall side view of the overall structure of a refiner 1 shown in cross section, which can be used for refining fibrous material, such as lignocellulose-containing wood or other fibrous material suitable for making paper or paperboard. Figure 1 The refiner 1 shown is of a conical type, but disc refiners, cone-disc refiners and cylindrical refiners may also be used as examples here. Typically, a refiner comprises: at least two substantially oppositely positioned refining elements, at least one of which is rotatable; and a refining chamber formed between each two substantially oppositely positioned refining elements. In the following, a refiner with only one rotatable refining element is described.

[0019] Figure 1The refiner 1 comprises a frame 2 and a stationary refining element 3 supported on the frame 2, i.e. a stator 3. The stator 3 comprises two or more stator blade segments 4, each of which comprises teeth and grooves located between the teeth. The teeth and grooves in each stator blade segment 4 form a refining surface 5 of the corresponding blade segment 4, so that 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 necessary number of blade segments 4 fixed closely to each other in the stator 3, thereby providing a complete refining surface 5 extending over the entire circumference of the stator 3. For the sake of clarity, both the refining surface of each individual stator blade segment 4 and the complete refining surface of the stator 3 are denoted herein by the same reference numeral 5.

[0020] The refiner 1 further comprises a rotatable refining element 6 of the refiner 1, i.e. a rotor 6. The rotor 6 comprises a hub 7. The rotor 6 further comprises two or more rotor blade segments 8 supported to the hub 7, each rotor blade segment 8 comprising teeth and grooves located between the teeth. The teeth and grooves in each rotor blade segment 8 form a refining surface 9 of the respective 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 of the rotor 6 is formed by the refining surfaces 9 of the necessary number of blade segments 8 fixed closely to each other in the rotor 6, thereby providing a complete refining surface 9 extending over the entire circumference of the rotor 6. For the sake of clarity, the refining surface of each single rotor blade segment 8 and the complete refining surface of the rotor 6 are both denoted herein by the same reference numeral 9.

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

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

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

[0024] because Figure 1 The space between the rotor 6 and the frame 2 of the refiner 1 is not completely closed, so some fiber materials to be fed into the refiner 1 can be transferred from the right end of the refiner chamber 12 (i.e., from the first end 18 or the inner end 18 of the refiner 1 having a smaller diameter) into the refiner chamber 12, as shown in FIG. Figure 1 Accordingly, some of the refined materials may also leave the refiner 12 from the left end of the refiner 12 (ie, from the second end 19 or the outer end 19 of the refiner 1 having a larger diameter), as shown in FIG. Figure 1 As shown, a connection is provided from this left end to the intermediate space 16 .

[0025] exist Figure 1 In the embodiment of the refiner 1 of FIG. 1 , only one feed channel 13 is provided and is arranged at the first end 18 of the refiner 1 having a smaller diameter. A practical embodiment of the refiner may also comprise a second feed channel arranged at the second end 19 of the refiner 1 having a larger diameter, whereby the discharge channel 17 of the refiner 1 may be arranged, for example, somewhere between the first end 18 and the second end 19 of the refiner 1. In the following, reference numeral 18 and the term first end 18 or the term inner end 18 may denote both the first end 18 or the inner end 18 of the refiner 1 having a smaller diameter and the first end 18 or the inner end 18 of the refining element 3, 6 or the refining chamber 12 having a smaller diameter. Correspondingly, reference numeral 19 and the term second end 19 or the term outer end 19 may denote both the second end 19 or the outer end 19 of the refiner 1 having a larger diameter and the second end 19 or the outer end 19 of the refining element 3, 6 or the refining chamber 12 having a larger diameter.

[0026] It should be emphasized that, in addition to being applicable to the conical refiners disclosed above, the blade segments of the solutions described herein can also be applied to other types of conical refiners. In addition to being applicable to conical refiners, the blade segments of the solutions described herein can also be applied to disc refiners and cylindrical refiners, as well as refiners comprising both conical and disc-shaped portions.

[0027] Figure 2 is a schematic upper oblique view of a portion of a group of adjacent rotor blade segments 8, and Figure 3 is a schematic oblique upper view of a rotor blade segment 8 which is suitable for forming a part of a refining surface 9 of a rotor 6. In the following, the blade segment structure will be considered in more detail based on the rotor blade segment 8, but the structure of the stator blade segment 4 is substantially similar unless disclosed otherwise.

[0028] The blade segment 8 comprises an inner end edge 20 or a first end edge 20, which points to the inner end 18 of the rotor 6 having a smaller diameter. The blade segment 8 also comprises an outer end edge 21 or a second end edge 21, which points to the outer end 19 of the rotor 6 having a larger diameter. In conical refiners and cylindrical refiners, the inner end edge of the blade segment serves as the axial inner end of the blade segment, and the outer end edge of the blade segment serves as the axial outer end of the blade segment, and the direction from the axial inner end toward the axial outer end provides the longitudinal axis of the blade segment, and the longitudinal axis of the blade segment is in Figure 3 In a disc refiner, the inner end edge of the blade segment will be the radially inner end of the blade segment, the outer end edge of the blade segment will be the radially outer end of the blade segment, and the direction from the radially inner end towards the radially outer end thus provides the longitudinal axis of the blade segment.

[0029] The blade segment 8 further comprises a first side edge 22 or a front side edge 22, which extends from the inner end edge 20 of the blade segment 8 to the outer end edge 21 of the blade segment 8 and is the side edge of the blade segment 8 that first meets the edge of the opposing blade segment, and thus points in the intended direction of rotation RD of the rotor 6. The blade segment 8 further comprises a second side edge 23 or a rear side edge 23, which is opposite to the first side edge 22 and extends from the inner end edge 20 of the blade segment 8 to the outer end edge 21 of the blade segment 8 and is the side edge of the blade segment 8 that last meets the edge of the opposing blade segment, and thus points in the direction opposite to the intended direction of rotation RD of the rotor 6. The inner end edge 20 and the outer end 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 comprises a body 24 having a front surface 25 pointing towards the refining chamber 12 of the refiner 1 and a background surface 26 pointing towards the hub 7 of the rotor 6. The front surface 25 of the blade segment body 24 is provided with teeth 27 and grooves 28 which together provide the refining surface 9 of the blade segment 8. The teeth 27 serve for defibering and refining the material to be refined and the grooves 28 serve for conveying the material to be refined forward along the refining surface 9.

[0031] The blade segment 8 further comprises fastening holes 31, 32 for accommodating fastening means, such as bolts, for fastening the blade segment 8 directly or via supporting means, such as a fixing ring 33, to the hub 7 or any supporting structure of the rotor 6. The blade segment 8 further comprises extensions or shoulders 34, 35, 36, 37 at its corners, where the blade segment 8 and its adjacent blade segment 8 are in lateral contact with each other, so that they can support each other.

[0032] When the blade segment according to the solution described herein is used in a through-feed refiner, it is provided with an opening to allow pulp to be fed / discharged through the refining surface of the stator and / or rotor. In this context, the opening is arranged at least at one side edge of the blade segment in the middle portion of the longitudinal axis of the blade segment.

[0033] exist Figures 2 to 3 In the blade segment 8 of the present invention, there is a continuous slit at the first side edge 22 of the blade segment 8, which extends uninterruptedly between a shoulder 34 on the side of the first side edge 22 of the blade segment 8 and at the first end edge 20 of the blade segment 8 and a shoulder 36 on the side of the first side edge 22 of the blade segment 8 and at the second end edge 21 of the blade segment 8. The continuous, uninterrupted slit or bay is formed by two substantially straight long edge portions 22a, 22b connected by a bevel 22c, wherein the direction of the long edge portions 22a, 22b is arranged to deviate from the direction of the longitudinal axis LA of the blade segment 8 towards the central part of the blade segment 8 at the first side edge 22, i.e., deviate to the same direction relative to the direction of the longitudinal axis LA. The bevel 22c is in turn arranged to deviate from the direction of the longitudinal axis LA of the blade segment 8 at the first side edge 22 away from the central part of the blade segment 8, i.e., deviate to the opposite direction relative to the longitudinal axis LA of the blade segment 8 from the long edge portions 22a, 22b. and Figure 2 and Figure 3 Unlike shown, there may be one or more shoulder members along the side edge(s) by which the slit is interrupted here and there, thereby providing a notch between two shoulder members.For example, the ramp 22c may extend to contact an adjacent segment.

[0034] In other words, the slit or partition at the first side edge 22 of the blade segment 8 is arranged so that the first side edge 22 does not form a completely straight line between the shoulder member 34 at the inner end edge 20 and the shoulder member 36 at the outer end edge 21, but forms a longitudinal slit or partition with a gentle zigzag or lightning-shaped edge. This slit or partition at the first side edge 22 of the blade segment 8 provides an opening 14 at the first side edge 22 of the blade segment 8. The opening 14 extends from the front surface 25 of the blade segment body 24 to the rear surface or back side 26 of the blade segment body 24, thereby extending through the entire thickness of the blade segment 8 or the blade segment body 24.

[0035] Furthermore, according to an embodiment of the blade segment 8, Figure 2 It can be seen that on the two side edges 22 and 23 of the blade segment 8, the blade segment 8 includes a basically similar opening 14, so the opening at the second side edge 23 also extends from the second side edge 23 toward the opposite first side edge 22, so that the second side edge 23 does not form a completely straight line between the inner end edge 20 and the outer end edge 21.

[0036] When the above-mentioned blade segments are assembled adjacent to each other to form the refining surface 5 of the stator 3 or the refining surface 9 of the rotor 6, continuous longitudinal slit-like openings or discontinuous longitudinal slit-like openings are provided between adjacent blade segments.

[0037] Figure 5 8 is a schematic top plan view of another blade segment 8. Figure 5 In the blade segment 8 of the embodiment of the present invention, the first side edge 22 of the blade segment 8 includes a plurality of openings 14, each of which has the form of a notch extending from the first side edge 22 toward the opposite second side edge 23. In other words, the opening 14 is provided at the first side edge 22 of the blade segment 8, so that the first side edge 22 does not form a completely straight line between the inner end edge 20 and the outer end edge 21. The opening 14 extends from the front surface 25 of the blade segment body 24 to the rear surface or back surface 26 of the blade segment body 24, the opening 14 thus extending through the entire thickness of the blade segment 8 or the blade segment body 24. In addition, the blade segment 8 may include one or more similar openings 14 (i.e., notches) extending from the second side edge 23 toward the opposite first side edge 22, so that the second side edge 23 also does not form a completely straight line between the inner end edge 20 and the outer end edge 21.

[0038] Figure 3 and Figure 5 Blade segment 8 or Figure 3 and Figure 5The refining surface 9 of the blade segment 8 further comprises a feed groove 29. The feed groove 29 is arranged to extend from the opening 14 arranged in the first side edge 22 of the blade segment 8 towards at least one other edge of the blade segment 8 (at Figure 3 and Figure 5 The feed groove 29 is formed in a first embodiment of the present invention and extends toward the second side edge 23 of the blade segment 8 in the embodiment of the present invention, so that the feed groove 29 intersects the teeth 27 and the grooves 28. The feed groove 29 has a first end 29a located at the opening 14 and a second end 29b facing away from the opening 14. The opening 14 located at the first side edge 22 of the blade segment 8 (i.e., located at the front side edge) and the feed groove 29 form a flow connection so that the material to be refined and supplied from the side of the back side 26 of the blade segment 8 through the opening 14 toward the front surface 25 of the blade segment 8 enters the feed groove 29 and flows along the feed groove 29 toward the central part of the blade segment 8, thereby conveying the material to be refined through the refining surface 9. At the same time, when the blade segment 8 rotates with the rotor 6, the force acting on the material flowing in the feed groove 29 forces the material to leave the feed groove 29 and enter the grooves 28 held between the teeth 27, thereby distributing the material to be refined on the refining surface 9 of the blade segment 8.

[0039] Feeding or supplying material through the openings 14 in the side edges 22 of the blade segments 8 causes the material to flow immediately over the refining surface 9 at least partially in the circumferential direction of the refining surface 9, without the need (as occurs in refiners where the feeding or supply of material takes place on the inner end edges of the blade segments) to convert the flow of the supplied material from an axial or radial direction into an at least partially rotational movement in the circumferential direction of the refining surface. This reduces, for example, the energy consumption of the refiner by avoiding those refining operating features that do not directly increase the refining efficiency.

[0040] exist Figure 2 and Figure 3 In the embodiment of the present invention, the feed groove 29 has a first end 29a located at the slit or partition on the first side edge 22 of the blade segment 8 and a second end located at or near the slit or partition on the second side edge 23 of the blade segment 8 (i.e., the opposite side edge 23 of the blade segment 8). In particular, the first end 29a of the feed groove 29 is positioned near the fixing ring, preferably just before or after the fixing ring, where the blade segment is assembled to the corresponding fine grinding element. Figure 2 and Figure 3In the embodiment of the present invention, the feed groove 29 enhances the flow of pulp over the refining surface, especially near those areas of the slit where the retaining ring interrupts the otherwise continuous slit, thereby preventing the pulp from freely reaching the refining surface and around the bolt holes. Similarly, if the slit is discontinuous, interrupted by a shoulder member, the first end 29a of the feed groove 29 will preferably be located near the shoulder, and the groove 29 will extend over the bolt hole.

[0041] In order to increase the strength of the construction of the refining surface 9 at the feed groove 29, the teeth 27 are staggered at the feed groove 29. The staggering of the teeth 27 at the feed groove 29 means (see in more detail Figure 4 In an embodiment), the teeth 27 located at one side of the feed groove 29 relative to the longitudinal axis LA of the blade segment 8 are arranged to extend into the groove 28 between the teeth 27 located at the opposite side of the feed groove 29 relative to the longitudinal axis LA of the blade segment 8, and vice versa.

[0042] exist Figure 4 An embodiment of the staggering of the teeth 27 is shown in more detail in FIG. Figure 4 is a schematic upper oblique view of a feed groove 29 in a rotor blade segment 8. Similar staggering of the teeth 27 can also be applied to Figure 5 In the blade segment of , in order to enhance the visibility of the feed groove path, the teeth 27 are not drawn at the feed groove 29.

[0043] To describe in more detail Figure 4 In an embodiment, it can be specified that, with respect to the feed groove 29 in the longitudinal direction of the blade segment 8, there are first teeth 27a and first grooves 28a located between the first teeth 27a, which extend from the direction of the inner end edge 20 of the blade segment 8 towards the feed groove 29 and up to the feed groove 29. It can also be specified that, with respect to the feed groove 29 in the longitudinal direction of the blade segment 8, there are second teeth 27b and second grooves 28b located between the second teeth 27b, which extend from the direction of the feed groove 29 (i.e. from the feed groove 29) at least partially towards the outer end edge 21 of the blade segment 8.

[0044] The first tooth 27a has an end 27a', which faces the outer end edge 21 of the blade segment 8 (i.e., faces the second tooth 27b) and extends into the second grooving 28b between two adjacent second teeth 27b. The second tooth 27b has an end 27b', which faces the inner end edge 20 of the blade segment (i.e., faces the first tooth 27a) and extends into the first grooving 28a between two adjacent first teeth 27a.

[0045] Figure 4The ends 27a', 27b' of the blade teeth 27a, 27b in the embodiment are linearly downwardly descending inclined surfaces, which are arranged to be partially staggered with each other, so that the downwardly descending inclined end 27a' of the first blade tooth 27a partially extends into the second blade groove 28b and its downwardly descending inclined end 27b' between two adjacent or neighboring second blade teeth 27b, and correspondingly, the downwardly descending inclined end 27b' of the second blade tooth 27b partially extends into the first blade groove 28a and its downwardly descending inclined end 27a' between two adjacent or neighboring first blade teeth 27a. Figure 4 In the embodiment of the present invention, the oppositely directed ends 27a', 27b' of the first and second teeth 27a, 27b are therefore arranged to extend successively into the oppositely positioned grooves 28a, 28b between the oppositely positioned teeth 27a, 27b. The oppositely directed linearly downwardly descending inclined ends 27a', 27b' of the first and second teeth 27a, 27b form or provide an upwardly open V-shaped feed groove 29.

[0046] and Figure 4 Unlike the embodiment of the present invention, instead of a linearly downwardly descending inclined surface, the ends 27a', 27b' of the teeth 27a, 27b may alternatively be inclined surfaces that descend downward, for example, in a convex manner or in a concave manner, so as to form or provide an upwardly open feed groove 29 between the oppositely directed ends 27a', 27b' of the first and second teeth 27a, 27b. Thus, the feed groove 29 may have a U-shaped profile or even a profile similar to a silhouette of a flying bird.

[0047] The staggered teeth 27, 27a, 27b at the feed groove 29 form a stronger tooth configuration, wherein the staggered teeth 27, 27a, 27b or their ends support each other at the feed groove 29, thereby preventing the teeth from buckling at the feed groove 29. The staggered teeth 27 at the feed groove 29 also equalize the cutting edge lengths of the blade segments 8 as the teeth wear. In addition, there is more tooth material at the feed groove 29 for wear, thereby increasing the life of the blade segments.

[0048] The material to be refined is fed from the first end 29a of the feed groove 29 from the back side 26 of the blade segment 8 through the opening 14 into the feed groove 29. The material flows along the feed groove 29 from the first end 29a of the feed groove 29 toward 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 knife grooves 28 between the knife teeth 27 and on top of the knife teeth 27 into the refining chamber 12 between the stator blade segment 4 and the rotor blade segment 8.

[0049] According to an embodiment of the blade segment, the volume of the feed groove 29 is arranged to decrease along its path from a first end 29a of the feed groove 29 towards a second end 29b thereof. The decreasing volume of the feed groove 29 refers to the cross-sectional area of ​​the feed groove decreasing from the first end 29a of the feed groove 29 towards its second end 29b. The decreasing volume of the feed groove 29 towards its second end effectively forces the material to be refined and fed into the feed groove 29 to leave the feed groove 29, into the slits 28 between the teeth 27, and over the tops of the teeth 27 into the refining chamber 12 between the stator blade segment 4 and the rotor blade segment 8. The volume of the feed groove 29 may decrease substantially continuously from the first end 29a of the feed groove 29 towards the second end 29b of the feed groove 29, or may decrease stepwise along the feed groove from a preceding tooth to a succeeding tooth.

[0050] According to an embodiment of the blade segment, a decreasing volume of the feed groove in its longitudinal direction is provided by arranging the angle of the downwardly descending inclined ends of the staggered teeth relative to the normal of the refining surface at the feed groove to decrease along the feed groove from a first end of the feed groove towards a second end of the feed groove. Figure 6a and Figure 6b An example of an embodiment similar to this is schematically shown in FIG. Figure 6a The staggering of the teeth 27a, 27b at the first end 29a of the feed groove 29 is schematically shown, and Figure 6b The staggering of the teeth 27 a , 27 b at the second end 29 b of the feed groove 29 is schematically shown.

[0051] Figure 6a and Figure 6b The first tooth 27a and its end 27a' are shown, which are partially located behind the second tooth 27b and its end 27b'. Figure 6a and Figure 6b In addition, Figure 6a and Figure 6b The normal 30 of the finely ground surface 9 of the blade segment 8 at the feed groove 29 is shown and Figure 6a , the angle a1 between the normal line 30 at the first end 29a of the feed groove 29 and the downwardly descending end 27a' of the first tooth 27a and the angle b1 between the normal line 30 and the downwardly descending end 27b' of the second tooth 27b are shown; and Figure 6b 2 shows the angle a2 between the normal line 30 at the second end 29b of the feed groove 29 and the downwardly descending end 27a' of the first tooth 27a and the angle b2 between the normal line 30 and the downwardly descending end 27b' of the second tooth 27b. Figure 6a and Figure 6bIt can be seen that the angle a1 between the normal line 30 at the first end 29a of the feed groove 29 and the downwardly descending end 27a' of the first tooth 27a is greater than the angle a2 between the normal line 30 at the second end 29b of the feed groove 29 and the downwardly descending end 27a' of the first tooth 27a. And similarly, the angle b1 between the normal line 30 at the first end 29a of the feed groove 29 and the downwardly descending end 27b' of the second tooth 27b is greater than the angle b2 between the normal line 30 at the second end 29b of the feed groove 29 and the downwardly descending end 27b' of the second tooth 27a. The cross-sectional area of ​​the feed groove 29 (and therefore the volume of the feed groove 29) decreases from the first end 29a of the feed groove 29 toward the second end 29b of the feed groove 29.

[0052] Figure 6a and Figure 6b The embodiment of the feed groove 29 has the effect of slowing down the outflow of material from the feed groove, thereby allowing a substantially uniform outflow of material from the feed groove by preventing the material from escaping from the feed groove in an explosive manner. At the same time, it increases the total cutting edge length of the teeth and therefore of the complete refining surface. These features together with the described blade segments (i.e. with blade segments having a material supply on their side edges and therefore a significant material flow in their circumferential direction) result in an improved refining process for the material to be refined.

[0053] exist Figure 6a and Figure 6b In the embodiment of the present invention, the normal 30 of the refining surface 9 of the blade segment 8 at the feed groove 29 forms the center line of the feed groove 29 in such a way that the angle between the normal 30 and the downwardly descending end 27a' of the first tooth 27a and the angle between the normal 30 and the downwardly descending end 27b' of the second tooth 27b are substantially equal along the feed groove 29. Thus, for example, the angles a1 and b1 are substantially equal to each other, and the angles a2 and b2 are substantially equal to each other. However, the angle between the normal 30 and the downwardly descending end 27a' of the first tooth 27a and the angle between the normal 30 and the downwardly descending end 27b' of the second tooth 27b may be arranged to be different from each other. In this case, for example, the angles a1 and b1 may be arranged to be slightly different from each other, and the angles a2 and b2 may be arranged to be slightly different from each other. In this case, by intentionally making the angle between the normal line 30 and the downwardly descending end 27a' of the first tooth 27a and the angle between the normal line 30 and the downwardly descending end 27b' of the second tooth 27b different from each other in different ways at different portions along the feed groove 29, the outflow of the material to be refined from the feed groove 29 can be controlled in different ways at different portions along the feed groove 29.

[0054] According to an embodiment of the blade segment, the vertical position of the plane of incidence of the downwardly descending inclined ends of the staggered teeth is arranged to be substantially constant along the feed groove. Figure 6a and Figure 6b An example of an embodiment similar to this is also schematically shown in , and the incident plane of the opposite downwardly descending inclined ends 27a', 27b' of the staggered teeth 27a, 27b is schematically shown, which is schematically indicated by the reference numeral PI. The incident plane PI is arranged at a distance H from the upper surface of the body 24 of the blade segment 8, the upper surface of the body 24 of the blade segment 8 being schematically indicated by a dotted line, which is indicated by the reference numeral 24'. When the distance H of the incident plane PI from the upper surface 24' of the body 24 of the blade segment 8 is arranged to be substantially constant along the feed groove 29, it can be avoided that the incident plane PI becomes the top of the fine grinding surface 9 of the blade segment before the end of the operating life of the blade segment 8.

[0055] According to an embodiment of the blade segment, the feed groove is arranged to intersect the teeth and the grooves at an angle. According to this embodiment, the feed groove 29 preferably intersects the teeth 27 and the grooves 28 at an angle of from 90 degrees to ±45 degrees. The effect of this embodiment is a better distribution of the material to be refined from the feed groove 29 into the grooves 28 and onto the upper surface of the teeth 27, i.e. into the refining chamber 12.

[0056] According to an embodiment of the blade segment, the feed groove is curved in its extension direction. According to this embodiment, the second end 29b of the feed groove 29 is located at a different position along the longitudinal axis LA of the blade segment than the first end 29a of the feed groove 29. In other words, the ends 29a, 29b of the feed groove are not located at the same normal level (normal plane) relative to the longitudinal axis LA, but the first end 29a may be located at one normal level (e.g., closer to the first end edge 20 of the blade segment 8) and the second end 29b is located at another normal level (i.e., farther away from the first end edge 20 of the blade segment 8). An advantageous effect of this embodiment is that the pulp flow is directed to a portion of the refining surface 9 that does not coincide with the recesses at the side edges (multiple) 22, 23 of the blade segment 8, or to an area of ​​the refining surface 9 that may be difficult for the pulp flow to access, such as the area around the fastening hole of the blade segment 8.

[0057] It is obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways.The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

1. A blade segment (4, 8) of a refiner (1) for refining fibrous material, the blade segment (4, 8) comprising: a first end edge (20) and a second end edge (21), a first side edge (22) and a second side edge (23) opposite to the first side edge (22), the first side edge (22) and the second side edge (23) extending between the first end edge (20) and the second end edge (21), a fine grinding surface (5, 9) comprising, on a front surface (25) of the blade segment (4, 8), a plurality of teeth (27, 27a, 27b) and grooves (28, 28a, 28b) between the teeth, at least one opening (14, 15) at least at one side edge (22, 23), said opening extending through the entire thickness of the blade segment body (24), and at least one feed groove (29) on the refining surface (5, 9), the feed groove (29) extending from the opening and intersecting the teeth (27, 27a, 27b) and the grooves (28, 28a, 28b) for conveying material to be refined through the refining surface (5, 9), It is characterized in that The teeth (27, 27a, 27b) of the blade segments (4, 8) are staggered at the feed groove (29).

2. The blade segment according to claim 1, characterized in that The openings (14, 15) are continuous slits at the side edges (22, 23) between extensions arranged at the corners of the blade segments (4, 8).

3. The blade segment according to claim 1, characterized in that The openings (14, 15) are recesses at the side edges (22, 23) extending toward the opposite side edges (22, 23).

4. The blade segment according to claim 1, characterized in that The teeth (27, 27a, 27b) are staggered at their end portions, which point in opposite directions at the feed groove (29).

5. The blade segment according to claim 4, characterized in that The staggered ends (27a', 27b') of the staggered blade teeth (27a, 27b) pointing in opposite directions include downwardly descending inclined ends (27a', 27b') arranged to form an upwardly open feed groove (29).

6. The blade segment according to claim 5, characterized in that The ends (27a', 27b') of the staggered blade teeth (27, 27a, 27b) are linearly downwardly inclined ends (27a', 27b'), and the linearly downwardly inclined ends are arranged to form a V-shaped feeding groove (29) that is open upward.

7. A blade segment according to any one of the preceding claims, characterized in that The volume of the feed groove (29) is arranged to decrease from a first end (29a) of the feed groove (29) located at the opening (14, 15) towards a second end (29b) of the feed groove (29).

8. The blade segment according to claim 7, characterized in that The angles (a1, a2, b1, b2) of the downwardly descending inclined ends (27a', 27b') of the teeth (27, 27a, 27b) relative to the normal (30) of the refining surface (5, 9) at the feed groove (29) are arranged to decrease along the feed groove (29) from the first end (29a) of the feed groove (29) toward the second end (29b) of the feed groove (29).

9. The blade segment according to claim 8, characterized in that The angles (a1, b1; a2, b2) between the normal (30) of the refining surface (5, 9) and the downwardly descending inclined ends (27a', 27b') of the opposing teeth (27, 27a, 27b) forming the feed groove (29) are equal.

10. The blade segment according to any one of claims 5 to 9, characterized in that The vertical position of the plane of incidence (PI) of the staggered downwardly descending inclined ends (27a', 27b') of the staggered blade teeth (27, 27a, 27b) is arranged to be constant along the feed groove (29).

11. The blade segment according to any one of the preceding claims, characterized in that The feed groove (29) is arranged to intersect the blade teeth (27, 27a, 27b) and the blade grooves (28, 28a, 28b) at an angle.

12. The blade segment according to claim 11, characterized in that The feed groove (29) is arranged to intersect the blade teeth (27, 27a, 27b) and the blade grooves (28, 28a, 28b) at an angle of 90 degrees to ±45 degrees.

13. A blade segment according to any one of the preceding claims, characterized in that The feeding groove (29) is curved along its extending direction.

14. A refiner for refining fiber material, characterized in that: The refiner (1) comprises at least one blade segment (4, 8) according to any one of claims 1 to 13.

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