Blade segments for fine grinding machines

Abstract

A blade segment (4, 4a, 4b, 8, 8a, 8b) of a refiner (1) for refining fibrous material. The 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 first side edge (22) and the second side edge (23) extending between the first end edge (20) and the second end edge (21). The segment further comprises: a refining surface (5, 9) comprising teeth (27) and grooves (28) on a front surface (25) of the segment; and at least one opening (14, 15) at the side edge (22, 23), the opening passing through the entire thickness of the segment body (24) and extending towards the opposite side edge (22, 23). At least at the opening of the segment, on the side of the back face (26) of the segment, there is a height difference between the back face (26) at the first side edge and the back face (26) at the second side edge.

Description

Technical Field

[0001] The present invention relates to a refiner for refining fibrous material, and in particular to a blade segment of a refiner for refining fibrous material. 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 opposite to each other and which rotate relative to each other (i.e. one or both of them rotate). The refining element comprises 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] EP publication 3401439B1 discloses a blade segment comprising a refining surface on its front surface, the refining surface comprising teeth and grooves between the teeth. The blade segment of EP3401439B1 comprises, at least at one side edge of the blade segment, an opening extending through the entire thickness of the blade segment and towards the opposite side edge. The opening can be used to supply fiber material to be refined into a refining chamber between oppositely positioned refining elements of a refiner, and to discharge fiber material that has been refined in the refining chamber from the refining chamber. 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 ​​providing, at least at the opening of the blade segment, on the side of the background surface of the blade segment, a height difference between the background surface at a first side edge and the background surface at a second side edge.

[0007] The height difference on the side of the back side of the blade segment forms or provides a guide element or guide surface which enhances the feeding of the material to be refined through the opening to the refining surface of the blade segment and into the refining chamber of the refiner.

[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 plan view of a blade segment;

[0012] Figure 3 Is has Figure 2 A schematic top plan view of a set of two adjacent blade segments of an embodiment of a blade segment;

[0013] Figure 4 is a schematic upper oblique view of a portion of a set of further adjacent blade segments used in a rotor of a conical refiner;

[0014] Figure 5 yes Figure 2 , Figure 3 and Figure 4 A first embodiment of the blade segment is along Figure 3 and Figure 4 A schematic partial cross-sectional end view taken along cross-sectional line AA is shown;

[0015] Figure 6 yes Figure 2 , Figure 3 and Figure 4 A second embodiment of the blade segment along Figure 3 and Figure 4 a schematic partial cross-sectional end view taken along cross-sectional line AA as shown; and

[0016] Figure 7 yes Figure 2 , Figure 3 and Figure 4 A third embodiment of the blade segment is along Figure 3 and Figure 4 Schematic partial cross-sectional end view taken along cross-sectional line AA is 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 1The 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 1 The 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 1The 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 material 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 plan view of a blade segment 4, 8 suitable for forming a part of a refining surface 5, 9 of a stator 3 or a rotor 6, wherein the blade segment 4, 8 is formed by arranging the necessary number of blade segments close to each other around the circumference of the stator 3 or the rotor 6. Figure 2 The blade segments 4, 8 are provided with a complete fine grinding surface 5, 9. Figure 3 is a Figure 2 Schematic top plan view of a set of two adjacent blade segments 4a, 4b, 8a, 8b of an embodiment of a blade segment 4, 8, Figure 3 The manner in which the blade segments 4 , 8 are mounted in the respective stator 3 or rotor 6 is shown.

[0028] The blade segment 4, 8 comprises an inner end edge 20 or first end edge 20, which points to the inner end 18 of the refining element 3, 6 having a smaller diameter. The blade segment 4, 8 also comprises an outer end edge 21 or second end edge 21, which points to the outer end 19 of the refining element 3, 6 having a larger diameter. The blade segment 4, 8 has a longitudinal axis extending from the inner end edge 20 to the outer end edge 21, and a width direction of the longitudinal axis, the longitudinal axis of the blade segment being schematically indicated by the arrow LA. When mounted in a refiner, the longitudinal axis LA provides the axial direction of the refiner in the case of a conical refiner and a cylindrical refiner, and provides the radial direction of the refiner in the case of a disc refiner.

[0029] The blade segments 4, 8 further include a first side edge 22 or a front side edge 22, which extends from the inner end edge 20 of the blade segments 4, 8 to the outer end edge 21 of the blade segments 4, 8 and is the side edge of the blade segments 4, 8 that first meets the edge of the opposing blade segment during the rotation of the rotor 6, so that it is the side edge of the blade segment pointing in the intended rotation direction RD of the rotor 6. The blade segments 4, 8 further include a second side edge 23 or a rear side edge 23, which is opposite to the first side edge 22 in the width direction of the blade segments 4, 8. The second side edge 23 extends from the inner end edge 20 of the blade segments 4, 8 to the outer end edge 21 of the blade segments 4, 8 and is the side edge of the blade segments 4, 8 that last meets the edge of the opposing blade segment during the rotation of the rotor 6, so that it is the side edge of the blade segment pointing in the direction opposite to the intended rotation direction 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 circumference of the blade segment 4 , 8 .

[0030] The blade segments 4, 8 comprise a body 24 having a front surface 25 directed towards the refining chamber 12 of the refiner 1 and a back or rear surface 26 directed towards the hub 7 of the rotor 6, e.g. Figure 5 The front surface 25 of the blade segment body 24 is provided with teeth 27 and grooves 28 which together provide the refining surface 5, 9 of the blade segment 4, 8. The teeth 27 are used for fiber separation and refining of the material to be refined, and the grooves 28 are used for conveying the material to be refined forward along the refining surface 5, 9.

[0031] The blade segments of the solution described herein comprise an opening 14, 15 at least on one of their side edges 22, 23. The openings 14, 15 may have the following features: Figure 2 and Figure 3 The form of the notch schematically shown in FIG. 1 or as described later in Figure 4 The form of a continuous slit or bay is schematically shown in FIG.

[0032] exist Figure 2In the blade segments 4, 8, there are openings 14, 15 on the first side edge 22 of the blade segments 4, 8. The openings 14, 15 extend from the first side edge 22 toward the opposite second side edge 23, so that the openings 14, 15 have a dimension in the direction of the longitudinal axis LA and a dimension in the width direction of the blade segments 4, 8. In other words, there is at least one opening 14 (i.e., one or more openings 14) at the first side edge 22 of the blade segments 4, 8, so that the first side edge 22 does not form a complete straight line between the inner end edge 20 and the outer end edge 21. The openings 14, 15 extend 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, so that the openings 14 extend through the entire thickness of the blade segment body 24 or the blade segments 4, 8.

[0033] Figure 2 An embodiment of a blade segment 4, 8 is shown having four openings 14 at a first side edge 22 of the blade segment 4, 8. Alternatively, the blade segment 4, 8 may include one or more openings 14 at a second side edge 23, the one or more openings extending from the second side edge 23 toward the opposite first side edge 22, so that the second side edge 23 does not form a complete straight line between the inner end edge 20 and the outer end edge 21.

[0034] Figure 4 Schematically shown is an oblique upper view of a portion of a set of further adjacent blade segments 8a, 8b as applied in a rotor 6 of a cone refiner 1 . Figure 4 The blade segments 8a, 8b of the present invention comprise shoulder elements 32, 33, 34, 35 located near the corners of the blade segments 8a, 8b, namely: the shoulder element 32 at the first end edge 20 of the blade segments 8a, 8b on the side of the first side edge 22, the shoulder element 33 at the first end edge 20 of the blade segments 8a, 8b on the side of the second side edge 23, the shoulder element 34 at the second end edge 21 of the blade segments 8a, 8b on the side of the first side edge 22, and the shoulder element 35 at the second end edge 21 of the blade segments 8a, 8b on the side of the second side edge 23. The shoulder elements 32, 33, 34, 35 are intended to come into contact with corresponding shoulder elements in adjacent blade segments when assembled to provide a part of the refining surface of the refining element of the refiner. Figure 4 Also schematically shown are fastening holes 36 for accommodating fastening means, such as bolts, for fastening the blade segments to the hub 7 of the rotor 6 or any supporting structure, either directly or via supporting means, such as a fixing ring 37 .

[0035] Between the shoulder elements 32, 34 on the first side edge 22 of the blade segments 8a, 8b, the first side edge 22 comprises a plurality of longer edge portions 22a connected by the elbow 22b therebetween, i.e., an elbow 22b is present between two consecutive longer edge portions 22a. The longer edge portions 22a and the elbow 22b are arranged to deviate from the direction of the longitudinal axis LA of the blade segments 8a, 8b, so that a substantially continuous slit-shaped or partition-shaped opening 14 is arranged at the first side edge 22 of the blade segments 8a, 8b.

[0036] exist Figure 4 In the embodiment, the longer edge portion 22a is arranged to deviate to the same direction relative to the direction of the longitudinal axis LA, and the elbow portion 22b turns away from the longer edge portion 22a to deviate to a direction different from the longer edge portion 22a relative to the direction of the longitudinal axis LA, but other mutual embodiments of the longer edge portion 22a and the elbow portion 22b are also feasible.

[0037] Similar longer edge portions and elbows as described above can also be applied to the second side edges 23 of the blade segments 8a, 8b, whereby the slit-like or partition-like openings 14 on the first side edges 22 and / or the second side edges 23 of the blade segments 8a, 8b serve as substantially continuous slit-like or partition-like openings 14 in a zigzag (broken line) form between adjacent blade segments 8a, 8b in the rotor 6.

[0038] like Figure 4 A similar blade segment configuration as disclosed in the related description may also be applied to the stator 3 of the refiner 1 accordingly.

[0039] Figure 2 and Figure 3 The blade segments 4, 4a, 4b, 8, 8a, 8b and Figure 4 The embodiment of the blade segments 8a, 8b also includes a feed groove 29. A more detailed discussion of the feed groove 29 is disclosed later in this specification.

[0040] Referring to the diagram schematically showing a plan view of a set of two adjacent blade segments 4a, 4b, 8a, 8b (ie, a first blade segment 4a, 8a and a second blade segment 4b, 8b) Figure 3 and Figure 4It can be seen that the opening 14, 15 in the first blade segment 4a, 8a is maintained between the first side edge 22 of the first blade segment 4a, 8a and the second side edge 23 of the adjacent second blade segment 4b, 8b. In other words, the walls 14a, 14b, 15a, 15b of the openings 14, 15 are formed by the side edges 22, 23 of two adjacent blade segments 4a, 4b, 8a, 8b, so that the first side edge 22 of the first blade segment 4a, 8a acts or forms the first wall 14a, 15a of the opening 14, 15 at each opening 14, 15, and the second side edge 23 of the second blade segment 4b, 8b acts or forms the second wall 14b, 15b of the opening 14, 15 at each opening 14, 15. Figure 3 In the embodiment, the openings 14, 15 have the form of notches. Figure 4 In the embodiment, the openings 14 have the form of continuous slits or partitions.

[0041] Figure 5 yes Figure 2 , Figure 3 and Figure 4 A first embodiment of the blade segments 8, 8a, 8b is along Figure 3 and Figure 4 A partial schematic cross-sectional end view taken along the cross-sectional line AA shown in FIG. Figure 5 The feed groove 29 is omitted. In addition, it should be noted that even in Figure 5 and later in Figure 6 and Figure 7 In the description, the configuration of the blade segment is described based on the rotor blade segment, and the similar configuration of the blade segment is also applicable to the stator blade segment.

[0042] exist Figure 5 In an embodiment of the present invention, at least at each opening 14 of the blade segments 8, 8a, 8b, a protrusion 30 is arranged in the back side or rear surface 26 at the first side edge 22 of the blade segments 8, 8a, 8b. In other words, at least at the first wall 14a of each opening 14, the blade segments 8, 8a, 8b comprise a protrusion 30 in the back side 26 of the blade segment body 24. The protrusion extends substantially beyond the rear plane of the blade segment, i.e. in the rotor 6 substantially towards the center of the rotor 6 when the blade segments 8, 8a, 8b are to be mounted to the rotor 6. The protrusion 30 may also extend over the entire longitudinal length of the blade segments 8, 8a, 8b, but the protrusion 30 at least substantially extends over the longitudinal extension of the opening 14 and preferably at least at each opening 14 of the blade segments 8, 8a, 8b.

[0043] exist Figure 5In the embodiment of the present invention, the projection 30 is a solid part of the body 24 of the blade segment 8, 8a, 8b. Alternatively, the projection 30 may be a separate part that is welded, brazed or fastened in some other way to the body 24 of the blade segment 8, 8a, 8b.

[0044] At the opening 14 of the blade segment 8 (and preferably, at least at each opening 14 of the blade segment), the disclosed protrusion 30 provides a height difference between the back face 26 at the first side edge 22 of the blade segment 8, 8a, 8b and the back face 26 at the second side edge 23 of the blade segment 8, 8a, 8b on the side of the back face or rear surface 26 of the blade segment 8, 8a, 8b. In other words, the disclosed protrusion 30 provides a height difference between the back face 26 at the first wall 14a of the opening 14 and the back face 26 at the second wall 14b of the opening 14 at the opening 14 on the side of the back face 26 of the blade segment 8, 8a, 8b (and preferably, at least at each opening 14 of the blade segment 8).

[0045] The height difference between the back side 26 at the first side edge 22 and the back side 26 at the second side edge 23 of the blade segment 8, 8a, 8b is considered relative to a reference level (reference plane) provided by the level or plane of the back side 26 of the blade segment 8, 8a, 8b, without taking into account possible protrusions in the body 24 of the blade segment 8, 8a, 8b for example supporting the blade segment 8, 8a, 8b to the hub 7 of the rotor 6 or cavities or pockets in the body 24 of the blade segment 8, 8a, 8b for lightening the structure of the body 24 of the blade segment 8, 8a, 8b.

[0046] The height difference provided by the protrusion 30 forms a wing-like structure or guide element or guide surface on the side of the back face 26 of the blade segment 8, 8a, 8b, which during operation of the refiner enhances the feeding of the material to be refined through the opening 14 from the back face 26 side of the blade segment to the front face 25 side of the blade segment (i.e. the feeding to the refining surface 9 of the blade segment 8, 8a or the feeding into the refining chamber 12 between the stator 3 and the rotor 6) by guiding the material to flow towards the opening 14. The feeding direction of the material to be refined in the rotor 6 is schematically indicated by arrow FI.

[0047] The improved flow of material to be refined into the refining chamber 12 has the effect that the material to be refined does not block the opening 14, which in turn has the effect of making the overall refining result more constant. Furthermore, the operating pressure of the refiner is better maintained, so that there is a higher pressure after the refiner than before, which provides a higher capacity in the refining. Being able to achieve a higher capacity also means that the same capacity as before can be obtained even if the opening area of ​​the opening 14 will be reduced. This in turn makes it possible to increase the cutting edge length of the teeth 27 of the blade segments 8, 8a, 8b, in particular for improving hardwood refining.

[0048] According to an embodiment, at the opening 14 of the blade segment, at least one side edge of the blade segment is inclined toward or away from the adjacent wall 14a, 14b at least in a portion of its thickness direction. According to this embodiment, at least at the (multiple) openings 14 of the blade segments 8, 8a, 8b, the first side edge 22 of the blade segments 8, 8a, 8b (i.e., the first wall 14a of the opening 14) and / or the second side edge 23 of the blade segments 8, 8a, 8b (i.e., the second wall 14b of the opening 14) is inclined at least in a portion of its thickness direction.

[0049] exist Figure 4 In an embodiment of the present invention, both the first side edge 22 of the blade segment 8, 8a, 8b and the second side edge 23 of the blade segment 8, 8a, 8b are inclined in the thickness direction thereof, so that the rear surface corner of the first side edge 22 extends further toward the intended rotation direction RD of the rotor 6 than the front surface corner (i.e., extends further from the second side edge 23 of the blade segment 8, 8a, 8b than the front surface corner), and the rear surface corner of the second side edge 23 extends further toward the intended rotation direction RD of the rotor 6 than the front surface corner of the second side edge 23 (i.e., the first side edge 22 of the blade segment 8, 8a, 8b extends further than the front surface corner of the second side edge). Such an inclination of the walls 14a, 14b of the opening(s) 14 has the effect of improving the feeding of the material to be refined through the opening 14 into the refining chamber 12 between the stator 3 and the rotor 6 when the refiner 1 is in use.

[0050] According to an embodiment, at least at each opening of the blade segment, the side edges of the blade segment are inclined at angles substantially different from each other at least in a portion of its thickness direction. According to this embodiment, at least at each opening 14 of the blade segments 8, 8a, 8b, the first side edge 22 of the blade segments 8, 8a, 8b (i.e., the first wall 14a of the opening 14) and the second side edge 23 of the blade segments 8, 8a, 8b (i.e., the second wall 14b of the opening 14) are inclined at angles substantially different from each other at least in a portion of its thickness direction.

[0051] According to this embodiment, at least at each opening 14 of the blade segments 8, 8a, 8b, the inclination angle of the first side edge 22 and the inclination angle of the second side edge 23 of the blade segments 8, 8a, 8b are different from each other at least in a portion of the thickness direction of the side edges 22, 23, so that Figure 5 The embodiments described herein also include embodiments in which only one of the side edges 22, 23 of the blade segments 8, 8a, 8b is inclined relative to the normal of the refining surface 9 of the blade segments 8, 8a, 8b.

[0052] The effect of this embodiment is that the cross-sectional opening area of ​​the opening 14 varies along at least a portion of the walls 14a, 14b. This provides a further means for influencing the flow of material to be refined through the opening 14 into the refining chamber 12.

[0053] According to an embodiment, at least at each opening of the blade segment, at least one side edge of the blade segment is bent at least in a portion of its thickness direction. According to this embodiment, at least at each opening of the blade segment, the first side edge 22 of the blade segment 8, 8a, 8b (i.e., the first wall 14a of the opening 14) and / or the second side edge 23 of the blade segment 8, 8a, 8b (i.e., the second wall 14b of the opening 14) is bent at least in a portion of its thickness direction.

[0054] exist Figure 6 In the embodiment, it is shown Figure 2 , Figure 3 and Figure 4 A second embodiment of the blade segments 8, 8a, 8b is along Figure 3 and Figure 4 The partial schematic cross-sectional end view taken along the cross-sectional line AA shown, with the feed groove 29 omitted, shows that both the first side edge 22 and the second side edge 23 of the blade segments 8, 8a, 8b are similar except that they are curved in the thickness direction thereof. Figure 5 Walls 14a, 14b.

[0055] Figure 6 This curved arrangement of the blade segment side edges 22, 23 in the embodiment also provides an inclination of the walls 14a, 14b of the opening 14, which has the effect of providing a smooth guidance for the pulp when the refiner 1 is in use, thereby improving the feeding of the pulp through the (multiple) openings 14 into the refining chamber 12 between the stator 3 and the rotor 6.

[0056] Figure 7 yes Figure 2 , Figure 3 and Figure 4 A third embodiment of the blade segments 8, 8a, 8b is along Figure 3 and 4 A partial schematic cross-sectional end view of the cross-sectional line AA is shown. Figure 7 The feed groove 29 is also omitted.

[0057] exist Figure 7 In the embodiment of the present invention, at least at each opening of the blade segments 8, 8a, 8b, a chamfer 31 is arranged in the back side 26 at the second side edge 23 of the blade segments 8, 8a, 8b. In other words, at least at the second wall 14b of each opening 14, the blade segments 8, 8a, 8b include a chamfer 31 in the back side 26 of the blade segment body 24. When the blade segments 8, 8a, 8b are mounted to the rotor 6, the chamfer 31 extends from the second side edge 23 of the blade segments 8, 8a, 8b substantially towards the intended rotation direction RD of the blade segments 8, 8a, 8b, or in other words, towards the first side edge 22 of the blade segments 8, 8a, 8b. The bevel 31 may also extend over the entire extension of the second side edge 23 of the blade segment 8 between the inner end edge 20 and the outer end edge 21 of the blade segments 8, 8a, 8b, but the bevel 31 extends at least substantially over the extension of the opening 14 in the direction between the inner end edge 20 and the outer end edge 21 of the blade segments 8, 8a, 8b.

[0058] The bevel 31 can be formed, for example, by removing material on the side of the back face 26 of the blade segments 8, 8a, 8b at the second side edge 23 of the blade segments 8, 8a, 8b at least at each opening 14. According to another example, the bevel 31 can be formed by removing material on the side of the back face 26 of the blade segments 8, 8a, 8b at the second side edge 23 of the blade segments 8, 8a, 8b at least at each opening 14.

[0059] At least at each opening 14 of the blade segment 8, 8a, 8b, the chamfer 31 also provides a height difference between the back face 26 at the first side edge 22 of the blade segment 8, 8a, 8b and the back face 26 at the second side edge 23 of the blade segment 8, 8a, 8b on the side of the back face 26 of the blade segment 8, 8a, 8b, so that the first side edge 22 of the blade segment 8, 8a, 8b extends further toward the direction in which the back face 26 of the blade segment 8, 8a, 8b faces than the second side edge 23 of the blade segment 8, 8a, 8b. Figure 5 and Figure 6Similarly to the embodiment of the invention, at least at the opening 14, the height difference provided by the bevel 31 forms a guide element or a guide surface at the first side edge 22 of the blade segment 8, 8a, 8b on the side of the back side 26 of the blade segment 8, 8a, 8b, which enhances the feeding of the material to be refined from the back side 26 of the blade segment 8, 8a, 8b through the opening 14 to the front surface 25 side of the blade segment 8, 8a, 8b, i.e., to the refining surface 9 of the blade segment 8, 8a, 8b or to the refining chamber 12 between the stator 3 and the rotor 6.

[0060] Referring back to the feed groove 29 and Figure 2 , Figure 3 and Figure 4 , the feed groove 29 is arranged to extend from the opening 14 arranged in the first side edge 22 of the blade segment 4, 4a, 4b, 8, 8a, 8b towards at least one other edge of the blade segment, in the embodiment of the figures, towards the second side edge 23 of the blade segment, 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 feed groove 29 forms a flow connection together with the corresponding notch-like or slit-like opening 14 at the first side edge 22, so that the material to be refined and supplied from the side of the back side 26 of the blade segment through the opening 14 towards the front surface 25 of the blade segment enters into the feed groove 29 and flows along the feed groove 29 towards the central part of the blade segment, thereby feeding the material to be refined through the refining surface 5, 9. At the same time, the force caused by the rotation of the rotor 6 acts on the material flowing in the feed groove 29 and forces the material to leave the feed groove 29 into the knife groove 28 held between the teeth 27 and onto the upper surface of the teeth 27, thereby distributing the material to be refined on the refining surface of the blade segment. It should be noted that the feed groove 29 is not a necessary feature of the blade segment, but a feature that can be utilized in some embodiments of the blade segment to improve the distribution of the material to be refined on the refining surface of the blade segment.

[0061] exist Figure 2 , Figure 3 and Figure 4 In the embodiment of the blade segment of , the feed groove 29 is arranged to intersect the teeth 27 and the grooves 28 at an angle. According to this embodiment, the feed groove 29 intersects the teeth 27 and the grooves 28 at an angle preferably from 90 degrees to ±45 degrees. The effect of this embodiment is that the material to be refined is better distributed from the feed groove 29 into the grooves 28 and onto the upper surface of the teeth 27, that is, into the refining chamber 12.

[0062] According to an embodiment of the blade segment, the feed groove is curved in its extension direction. The second end of the curved feed groove may be located at the same or different position in the longitudinal direction of the blade segment represented by the longitudinal axis LA of the blade segment than the first end of the feed groove. An advantageous effect of this embodiment is that the material to be fed onto the refining surface of the blade segment can be guided substantially freely to the desired portion of the refining surface.

[0063] Referring back to the feed groove 29 and Figure 4 In the embodiment of the present invention, the teeth 27 of the blade segments 8a, 8b are staggered at the feed groove. The teeth 27 are staggered at the feed groove 29 so that the ends of the teeth on the opposite sides of the feed groove (as seen in the direction of the longitudinal axis LA of the blade segments) are staggered at the feed groove 29.

[0064] According to an embodiment, the staggered ends of the staggered blade teeth pointing in opposite directions comprise downwardly descending inclined ends which are arranged to form an upwardly open feed groove.

[0065] The staggering of the teeth at the feed groove provides a strong tooth construction at the feed groove, wherein the staggered teeth support each other, thereby preventing the teeth from buckling at the feed groove.

[0066] It will be 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, 4a, 4b, 8, 8a, 8b) of a refiner (1) for refining fibrous material, the blade segment (4, 4a, 4b, 8, 8a, 8b) comprising: a body (24) having a front surface (25) and a back surface (26), a first end edge (20) and a second end edge (21), a first side edge (22) and a second side edge (23), the second side edge being 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 teeth (27) and grooves (28) on the front surface (25) of the blade segment (4, 4a, 4b, 8, 8a, 8b), at least one opening (14, 15) at the side edge (22, 23), the opening (14, 15) extending through the entire thickness of the blade segment body (24) and extending towards the opposite side edge (22, 23), It is characterized in that At least at the opening (14, 15) of the blade segment (4, 4a, 4b, 8, 8a, 8b), on the side of the back side (26) of the blade segment (4, 4a, 4b, 8, 8a, 8b), there is a height difference between the back side (26) at the first side edge (22) and the back side (26) at the second side edge (23).

2. The blade segment according to claim 1, characterized in that At the opening (14, 15) of the blade segment (4, 4a, 4b, 8, 8a, 8b), there is a protrusion (30) in the back surface (26) at the first side edge (22) for providing the height difference between the back surface (26) at the first side edge (22) and the back surface (26) at the second side edge (23) at the opening (14, 15).

3. The blade segment according to claim 1, characterized in that At the opening (14, 15) of the blade segment (4, 4a, 4b, 8, 8a, 8b), there is a chamfer (31) in the back face (26) at the second side edge (23) for providing the height difference between the back face (26) at the first side edge (22) and the back face (26) at the second side edge (23) at the opening (14, 15).

4. The blade segment according to claim 2, characterized in that At the opening (14, 15) of the blade segment (4, 4a, 4b, 8, 8a, 8b), there is a chamfer (31) in the back face (26) at the second side edge (23) for providing the height difference between the back face (26) at the first side edge (22) and the back face (26) at the second side edge (23) at the opening (14, 15).

5. The blade segment according to any one of claims 1 to 4, characterized in that At the opening (14, 15), at least one side edge (22, 23) is inclined over at least a portion of its thickness.

6. The blade segment according to any one of claims 1 to 4, characterized in that The side edges (22, 23) of the blade segments (4, 4a, 4b, 8, 8a, 8b) are inclined at different angles to each other at least over a portion of their thickness.

7. The blade segment according to any one of claims 1 to 4, characterized in that At the opening (14, 15), at least one side edge (22, 23) of the blade segment (4, 4a, 4b, 8, 8a, 8b) is bent over at least a portion of its thickness.

8. The blade segment according to any one of claims 1 to 4, characterized in that The blade segment is a rotor blade segment (8, 8a, 8b), and the first side edge (22) of the blade segment (8, 8a, 8b) is a front side edge (22), which is arranged to face the intended rotation direction (RD) of the rotor (6) of the refiner (1), and the second side edge (23) of the blade segment (8, 8a, 8b) is a rear side edge, which is arranged to face the direction opposite to the intended rotation direction (RD) of the rotor (6) of the refiner (1).

9. The blade segment according to claim 5, characterized in that At the opening (14) of the blade segment (8, 8a, 8b), at least a first side edge (22) of the blade segment (8, 8a, 8b) is inclined over at least a portion of its thickness towards an intended rotation direction (RD) of a rotor (6) of the refiner (1).

10. The blade segment according to claim 5, characterized in that At the opening (14) of the blade segment (8, 8a, 8b), a first side edge (22) of the blade segment (8, 8a, 8b) and a second side edge (23) of the blade segment (8, 8a, 8b) are both inclined over at least a portion of their thickness toward the intended rotation direction (RD) of the rotor (6) of the refiner (1), and the inclination angle of the second side edge (23) is different from the inclination angle of the first side edge (22).

11. The blade segment according to claim 5, characterized in that At the opening (14), at least one side edge (22, 23) of the blade segment (8, 8a, 8b) is bent over at least a portion of its thickness.

12. The blade segment according to any one of claims 1 to 4, characterized in that The blade segment (4, 4a, 4b, 8, 8a, 8b) comprises at least one feed groove (29) on the refining surface (5, 9), the feed groove (29) extending from the opening (14, 15) and intersecting the tooth (27) and the groove (28) for feeding material to be refined onto the refining surface (5, 9).

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

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

Images