Blade of refiner for refining lignocellulosic material and refiner comprising at least one blade

Abstract

The invention relates to a blade for a refiner for refining lignocellulosic material, the blade (10) being delimited by an inner periphery (11) and an outer periphery (12) and comprising a blade surface (13) having a refining portion (14) on which a plurality of refiner teeth (20) are arranged wherein each refiner tooth (20) extends from an outer tooth end (21) to an inner tooth end (22), and wherein the plurality of refiner teeth (20) are arranged such that a movement along a tooth extension from an outer tooth end (21) to an inner tooth end (22) of the refiner teeth (20) is also a movement along a first circumferential direction (D), and wherein the blade (10) further comprises at least one paddle (30) extending from an outer paddle end (31) to an inner paddle end (32) and connecting at least three refiner teeth (20), furthermore, the slurry shield (30) is arranged such that a movement along the slurry shield extension from the outer slurry shield end (31) to the inner slurry shield end (32) is also a movement along the first circumferential direction (D). The invention also relates to a refiner comprising at least one such blade.

Description

Technical Field

[0001] The present invention relates to a blade for a refiner for refining lignocellulosic material during pulp production and to such a refiner. Background Art

[0002] Disc refiners are commonly used in the pulping industry for refining lignocellulosic material for the production of fibrous materials such as paper and board.

[0003] A disc refiner comprises two or more opposing refining elements, at least one of which is rotatable. The rotating refining elements may be referred to as rotors or rotor side blades, while the non-rotating or stationary refining elements may be referred to as stators or stator side blades. Between the refining elements is a refining gap in which the material to be refined is ground against the refining surface. The refining surfaces of the refining elements include refiner teeth (bars) used to refine the lignocellulosic material during use, and also include a pulp dam (dam) that intersects the refiner teeth and lifts the lignocellulosic material toward the refining gap to ensure thorough refining.

[0004] Refining lignocellulosic material is costly as the energy consumption to achieve the required fibre quality is generally very high. There are some proposed improvements in this area but further development is needed to ensure the required fibre quality whilst providing more energy efficient refiner blades. Summary of the invention

[0005] The object of the present invention is to eliminate or at least minimize the above mentioned problems. This is achieved by a blade for a refiner and a refiner comprising such a blade according to the attached independent claims.

[0006] The blade according to the invention is defined by an inner periphery and an outer periphery and comprises a blade surface having a refining portion on which a plurality of refiner teeth are arranged. Each refiner tooth extends from an inner tooth end to an outer tooth end, and the plurality of refiner teeth are angled such that a movement along a bar extension from an outer tooth end to an inner tooth end of the refiner tooth is also a movement along a first circumferential direction. Furthermore, the blade comprises at least one dam extending from an inner dam end to an outer dam end and connecting at least three refiner teeth, wherein the dam is angled such that a movement along a dam extension from an outer dam end to an inner dam end is also a movement along a first circumferential direction.

[0007] The pulp barrier is thus arranged to effectively lift the lignocellulosic material into the refining gap while minimizing flow restriction, thereby reducing energy consumption during operation. This in turn enables the pulp barrier to feed the lignocellulosic material along the blades towards the outer periphery to ensure that the desired refining quality is achieved while reducing wear and energy consumption, as the pulp barrier presents less obstruction to the material flow than known prior art solutions.

[0008] According to some embodiments, the barrier height of at least one barrier is substantially equal to the tooth height of at least one of the teeth intersected by the barrier. This ensures that the barrier can lift the lignocellulosic material to the refining gap to improve the refining quality.

[0009] According to other embodiments, the barrier height of at least one barrier is 20% to 99%, preferably 20% to 85%, of the height of at least one of the refiner teeth to which the barrier is connected. Thus, a subsurface barrier is achieved, which enables steam flow and also improves the cross-bar flow of material.

[0010] In some embodiments, the blade comprises a barrier having a barrier height substantially equal to the tooth height and further comprises at least one barrier having a barrier height that is 20% to 99%, preferably 20% to 85%, of the tooth height of at least one of the refiner teeth to which the barrier is attached. Thus, barriers and subsurface barriers may be combined as desired to improve the flow of lignocellulosic material and steam while achieving high quality refining.

[0011] Suitably, the blade further comprises a groove extending adjacent to the pulp baffle on the side of the pulp baffle facing the outer periphery. Hereby, a pumping conveyance of the lignocellulosic material can be achieved, wherein the material after passing the pulp baffle can flow along the groove before entering the tooth grooves between the refiner teeth for further conveyance towards the outer periphery. This in turn improves energy efficiency and reduces wear of the refiner blade.

[0012] The width of the groove may increase towards the inner pulp barrier end. Thus, as the lignocellulosic material passes along the groove, it is urged into the tooth groove.

[0013] Furthermore, the width of the groove at the upper end is suitably at least equal to the width of the pulp barrier. Thus, the groove is wide enough to improve the flow of the lignocellulosic material. The width at the upper end is the distance from the outer side of the pulp barrier in radial direction to the point of the refiner teeth where the refiner teeth begin to taper towards the blade surface.

[0014] Suitably, the depth of the groove is at least equal to half the height of the barrier adjacent to the groove. Thus, the groove is deep enough to improve the flow of the lignocellulosic material.

[0015] Suitably, the blade further comprises a reinforcement portion at which the outer dam end is connected to the refiner tooth, said reinforcement portion being arranged on the side of the dam facing the inner periphery.Thereby, wear is reduced and the life of the blade is increased.

[0016] Furthermore, the outer barrier end of the first barrier and the inner barrier end of the second barrier can each be connected to the same blade, and the inner barrier end of the second barrier is closer to the inner periphery than the outer barrier end of the first barrier. Thus, grooves not spanned by the barriers are avoided, so that the lignocellulosic material cannot flow across the blade without being lifted to the refining gap. Furthermore, the barriers are angled or curved to improve the conveying of the lignocellulosic material.

[0017] Suitably, the outer barrier end of the first barrier and the outer barrier end of the adjacent barrier in the radial direction are each connected to a different refiner tooth in the first circumferential direction. Thus, the barriers have an overlap in the radial direction, which increases the strength of the blade and distributes the area subject to high wear across the entire blade, making the blade as a whole stronger.

[0018] In some embodiments, the blade is a blade section having a center angle of 10° to 360°. Where the blade is not circular, the blade section may be combined with a plurality of similar or identical blade sections to form a circular blade.

[0019] Furthermore, there may be at least one section lacking refiner teeth.Thus, unless in the refining section, the lignocellulosic material may be conveyed across the blades without being refined.

[0020] The invention also relates to a refiner for refining lignocellulosic material comprising at least one blade according to any embodiment of the invention.

[0021] Numerous additional benefits and advantages of the present invention will be readily appreciated by those skilled in the art in view of the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will now be described in more detail with reference to the accompanying drawings, in which:

[0023] Figure 1a A top plan view of a blade according to a first embodiment of the present invention is disclosed;

[0024] Figure 1b A top plan view of a blade according to a second embodiment of the present invention is disclosed;

[0025] Figure 2a A top plan view of a blade according to a third embodiment of the present invention is disclosed;

[0026] Figure 2bdiscloses a top plan view of a blade according to a fourth embodiment of the present invention;

[0027] Figure 3a discloses a top plan view of a blade according to a fifth embodiment of the present invention;

[0028] Figure 3b Public Figure 3a An enlarged view of one of the slurry blocks;

[0029] Figure 3c discloses a top plan view of a blade according to a sixth embodiment of the present invention;

[0030] Figure 4 A top plan view showing an embodiment in which the density of refiner teeth in each set of refiner teeth is different;

[0031] Figure 5 shows a top plan view of an embodiment having an outer portion;

[0032] Figure 6 A top plan view of an embodiment without a groove is shown;

[0033] Figure 7a A schematic diagram viewed from the side of the groove is disclosed; and

[0034] Figure 7b Another schematic diagram viewed from the side of the groove is disclosed.

[0035] All figures are schematic, not necessarily drawn to scale, and generally show only the parts necessary to illustrate the various embodiments, while other parts may be omitted or only implied. Unless otherwise indicated, any reference numerals appearing in multiple figures refer to the same object or feature in the figure. DETAILED DESCRIPTION

[0036] Figure 1a A blade 10 according to a first embodiment of the present invention is disclosed. The blade 10 according to any embodiment of the present invention shown in the drawings may be a portion of a circular blade of which only a portion is shown, or alternatively may be a blade segment configured to be mounted together with a plurality of similar blade segments to form a circular blade.

[0037] In use, the blade 10 is typically installed in a disc refiner (not shown) and serves to refine lignocellulosic material by acting as a blade in a pair of blades arranged to face each other, wherein at least one blade of the pair is arranged to rotate. Typically, the blades arranged to rotate in the disc refiner are referred to as rotor-side blades, while the blades arranged to be stationary are referred to as stator-side blades. In use, a refining gap is formed between the blades, so that the lignocellulosic material passing through the refining gap is refined by the refiner teeth arranged on each blade.

[0038] As used herein, the term "lignocellulosic material" refers to a material comprising cellulose, and preferably also lignin and hemicellulose. One example of such a material is wood, and other examples include other agricultural or forestry wastes. When a lignocellulosic material is refined with a disc refiner, the material is typically fed into the disc refiner through an opening at the center of one of the blades and refined while it moves radially outward between the blade pairs. Lignocellulosic material may also refer to a material containing primarily cellulose, such as cotton.

[0039] The present invention will be described with reference to various embodiments, and it is particularly noted that features from one embodiment can be freely introduced into another embodiment, unless such a combination is explicitly stated as inappropriate or undesirable. Therefore, the embodiments disclosed herein can be combined with each other as desired.

[0040] It should be noted that each embodiment shown in the drawings may be only a portion of a blade 10, which itself may include additional portions at the inner periphery 11, the outer periphery 12, and on each side shown in each drawing. Therefore, these drawings will be viewed as embodiments having a pattern of refiner teeth and blade guards that may be repeated across the entire blade 10 or may be provided in only a portion of the blade 10.

[0041] Figure 1a The blade 10 shown is defined by an inner periphery 11 and an outer periphery 12 and includes a blade surface 13. On the blade surface 13 is at least one refining portion 14 including a plurality of refiner teeth 20 extending outwardly from the blade surface 13. The refining portion 14 may extend across the entire blade surface 13, but in most embodiments, the blade surface 13 also includes other portions that do not include refiner teeth 20. Figure 1a In the embodiment shown, the blade 10 lacks the refiner teeth 20 in the portion near the inner periphery 11 , but the refiner teeth 20 may also be arranged near the outer periphery 12 or in other portions of the blade surface 13 .

[0042] The refiner teeth 20 each comprise an outer tooth end 21 and an inner tooth end 22, wherein the outer tooth end 21 is closer to the outer periphery 12 than the inner tooth end 22. The refiner teeth 20 are arranged such that a movement along the tooth extension, i.e. a movement along a single refiner tooth 20 from the outer tooth end 21 to the inner tooth end 22, is also a movement along a first circumferential direction D. When the blade 10 is arranged in a refiner, the first circumferential direction D is the direction of rotation, and the first rotational direction D is further perpendicular to a radial direction R, which is defined as the direction from a point on the inner periphery 11 to a point on the outer periphery 12 that is closest to the point on the inner periphery 11. A movement along the tooth extension is a movement along the first circumferential direction D, which is understood herein as a movement having a component directed along the first circumferential direction D. There may also be a component in a radial direction perpendicular to the first circumferential direction D.

[0043] The arrangement of the refiner teeth 20 means that they are inclined relative to the radial direction R to form a tooth angle α of less than 90 in the clockwise direction. In some embodiments, the refiner teeth 20 are parallel to each other, but in other embodiments, at least one of them may not be parallel to the other refiner teeth. In addition, in some embodiments, the refiner teeth form a straight line, but in some embodiments, the refiner teeth may be curved. In addition, in some embodiments, the refiner teeth 20 may vary across the blade 10, so that some of them form a straight line, while others are curved, and some of them are parallel, but others are not. At the inner tooth end 22, the teeth 20 preferably taper toward the blade surface 13. The tooth angle α of each refiner tooth 20 may be different, but is advantageously in the range of 5° to 60°.

[0044] At least one barrier 30 is also provided on the refining section 14 to which at least three refiner teeth 20 are connected. Each barrier 30 extends from an outer barrier end 31 to an inner barrier end 32, wherein the outer barrier end 31 is closer to the outer periphery 12 than the inner barrier end 32. The barriers 30 are further arranged so that the movement along the barrier extension, i.e. the movement along a single barrier 30 from the outer barrier end 31 to the inner barrier end 32 is also a movement along the first circumferential direction D. This means that the barriers 30 are inclined relative to the radial direction R to form a barrier angle β of less than 90° in the clockwise direction. The barrier angle β of each barrier 30 may be different, but is advantageously in the range of 30° to 85°. In an embodiment in which the barriers 30 are curved, the barrier angle β appropriately decreases when moving from the outer barrier end 31 towards the inner barrier end 32.

[0045] When the blade 30 is connected to the refiner tooth 20, a connection angle γ is formed in the corner facing the first circumferential direction D and facing the inner periphery 11. The connection angle γ is advantageously in the range of 30° to 85°, which ensures efficient refining of the lignocellulosic material and reduced energy consumption.

[0046] Preferably, the blade angle α may vary across the segment. Advantageously, a larger blade angle α is provided towards the center of the blade 10, i.e. towards the inner periphery 11, but a smaller blade angle is provided when the blade is closer to the outer periphery 12. Furthermore, the barrier angle β may vary across the segment, and advantageously, a smaller barrier angle β is provided near the inner periphery 11, while a larger barrier angle β is provided near the outer periphery 12. Thus, when moving across the blade 10 in the radial direction R from the inner periphery 11 to the outer periphery 12, the blade angle α preferably decreases, while the barrier angle β increases.

[0047] In the first embodiment, the refining section 14 includes a plurality of paddle blocks 30 arranged in this manner, but in other embodiments a single paddle block 30 may be provided instead. Furthermore, the paddle blocks 30 shown in FIG. 1 are arranged so that groups of refiner teeth 20 are connected by more than one paddle block 30, the paddle blocks 30 being arranged along the same refiner tooth 20 but at different distances from the inner periphery 11. In other embodiments, the paddle blocks 30 may be arranged alternatively so that only some of the refiner teeth 20 connected by one paddle block 30 are connected by another paddle block 30 closer to the inner periphery 11, or so that each refiner tooth 20 is connected to only one paddle block 30.

[0048] In addition, Figure 1a In the embodiment of the present invention, all refiner teeth 20 are connected by at least one paddle stop 30 with the refiner teeth 20 at the inner paddle stop end 32 of one paddle stop 30, which is also at the outer paddle stop end 31 of another paddle stop 30. In other embodiments, some refiner teeth 20 may not be connected to any paddle stop 30, or the positioning of the paddle stops 30 may be varied on the refining section 14 as desired.

[0049] The slurry baffles 30 may also form straight lines or curves, and they may be parallel or non-parallel to each other as desired.

[0050] The fact that the inner tooth ends 22 and the inner pulp barrier ends 32 of the teeth 20 and the pulp barrier 30 are arranged further forward in the first axial direction D than the outer tooth ends 21 and the outer pulp barrier ends 31 means that the pulp barrier 30 can lift the lignocellulosic material from the tooth grooves 40 into the refining gap to improve refining, while enabling the lignocellulosic material to be efficiently transported from the inner periphery 11 across the blade 10 to the outer periphery 12. This in turn reduces energy consumption, because the pulp barrier 30 is less obstructive to the flow of the lignocellulosic material than a pulp barrier 30 arranged at an angle of more than 90° to the radial direction R, i.e. the outer pulp barrier ends of the pulp barrier are further inclined in the first circumferential direction D.

[0051] exist Figure 1a In an embodiment of the invention, the barrier height of at least one barrier 30 is substantially equal to the tooth height of at least one tooth 20 intersected by the barrier 30. This means that the barrier 30 lifts the cellulosic material up to the refining gap and prevents lignocellulosic material which has not been refined by the refiner teeth 20 from crossing the barrier 30. By barrier height being substantially equal to tooth height is understood that they are equal within manufacturing tolerances or at least do not differ from each other by more than 10% of their height from the blade surface 13. In a first embodiment, all barriers 30 have this barrier height, but in other embodiments at least one of them may be lower. A barrier height substantially equal to tooth height is also advantageous in terms of increasing the pressure between the blades during refining.

[0052] Figure 1b A second embodiment is disclosed, which differs from the first embodiment in that at least one of the barriers 30 is a subsurface barrier, i.e. a barrier having a lower barrier height than the blade height of at least one refiner tooth 20 to which the barrier 30 is connected. In the second embodiment, the barrier height is between 20% and 99%, preferably between 20% and 85%, of the blade height of at least one of the refiner teeth to which the barrier 30 is connected. When using a blade 10 according to the invention, this has the advantage of promoting the flow of steam in a direction opposite to the flow direction of the lignocellulosic material, since the barriers 30 provide less obstacles to the flow in the tooth grooves 40. At the same time, the refining efficiency remains very close to that of the first embodiment described above, since most of the lignocellulosic material will be lifted to the refining gap, while the high-pressure steam, which normally moves along the tooth grooves 40, will be free to move and be allowed to enter the tooth grooves 40 on the outer side 34 of the barrier 30. Figure 1b In the second embodiment, all the slurry barriers 30 are subsurface slurry barriers, but in other embodiments, some of them may have Figure 1a Full tooth height shown. In some embodiments, subsurface slurry barriers are particularly advantageous for the outer periphery 12 where steam backflow occurs.

[0053] Figure 2aA third embodiment of the blade 10 is disclosed, which differs from the first and second embodiments in that it includes a groove 50 extending adjacent to the blade 30 on the outer side 34 of the blade 30, i.e., on the side of the blade 30 facing the outer periphery 12. The groove 50 extends along the blade 30 and is long enough to pass through at least three refiner teeth 20. In some embodiments, the groove 50 extends along the entire blade 30, i.e., from the inner blade end 32 to the outer blade end 31. The groove 50 is bounded by the outer side 34 of the blade 30 and the refiner teeth 20 at the location where the refiner teeth 20 begin to taper toward the blade surface 13 ( Figure 2a to Figure 2b (shown by the dashed line).

[0054] The grooves 50 may be viewed as interruptions of the refiner teeth 20, which extend from the outer tooth ends 21 and taper to the blade surface 13 at the grooves 50 and then continue from the paddle stops 30 toward the inner tooth ends 22. Alternatively, the grooves 50 may be viewed as providing the refiner teeth 20 with ends that taper toward the blade surface 13, thereby forming their inner tooth ends 22. In the third embodiment, all of the paddle stops 30 are provided with grooves 50, but in other embodiments, some of the paddle stops 30 may be free of grooves 50.

[0055] The advantage of the grooves 50 is that they enable the lignocellulosic material to be pumped across the blade 10 during use. This means that when the blade 10 rotates in the first circumferential direction D, the lignocellulosic material travels in one of the tooth grooves 40 to the pulp stop 30, is then lifted to the refining gap, and travels along the grooves 50 before entering the other tooth groove 40. This Figure 2a This delivery increases the energy efficiency of the refiner and reduces the wear of the blades 10, ensuring a longer life.

[0056] The width of the groove 50 may increase from the outer pulp barrier end 31 towards the inner pulp barrier end 32, thereby encouraging the lignocellulosic material to enter the tooth groove 40 as it moves along the groove 50. The groove 50 further has a groove width at the upper end, i.e. at the end furthest from the blade surface 13, which is at least equal to the upper width of the pulp barrier 40. The groove width is also understood to be the width in the radial direction R from the pulp barrier 30 to the refiner tooth 20 on the outer side 34 of the pulp barrier 30. At the upper end of the groove 50, the refiner tooth 20 is at its full height, but the refiner tooth 20 is appropriately tapered towards the outer side 34 of the pulp barrier 30 to reduce wear.

[0057] Figure 2bA fourth embodiment of the blade 10 is disclosed which is similar to the third embodiment in that it includes grooves 50 on the outer sides 34 of the dams 30, but is also similar to the second embodiment in that at least some of the dams 30 are subsurface dams. Pumping transport of the lignocellulosic material is further improved by the subsurface dams 30 which facilitate passing above the dams 30 to allow steam to flow, thereby reducing energy consumption and wear on the dams 30. Transport of the lignocellulosic material is shown as dashed arrows, similar to Figure 2a .

[0058] Figure 3a A fifth embodiment of a blade 10 is disclosed in which the refiner teeth 20 on one side of the groove 50 are not an extension of the refiner teeth 20 on the other side of the groove 50, but are arranged to be different in direction or inclination from each other. The density of the refiner teeth 20, i.e. how many refiner teeth 20 are provided on a surface portion of a given size, may also be different.

[0059] Furthermore, the fifth embodiment comprises a reinforcement portion 33 on at least one of the barriers 30, which is arranged where the outer barrier end 31 is connected to the refiner tooth 20. The reinforcement portion 33 is arranged on the side of the barrier 30 facing the inner periphery 11, i.e. on the side opposite to the outer side 34. More specifically, the reinforcement portion 33 is arranged at the corner where the barrier 30 meets the last refiner tooth 20 at the outer barrier end 31. The reinforcement portion 33 is thus arranged where the wear of the barrier 30 by the lignocellulosic material is particularly high and thus serves to protect the barrier 30 and extend the life of the blade 10. Suitably, the reinforcement portion 33 is integral with the barrier 30 and the refiner tooth 20, but in some embodiments it may be a separate portion added during manufacture at the outer barrier end 31 to the corner between the barrier 30 and the refiner tooth 20.

[0060] In the fifth embodiment, at least one of the paddle guards 30 also includes a reinforcement portion 33 at one or more intersections of the paddle guard 30 and the refiner teeth 20, and this is particularly advantageous in terms of overall reduction of wear on the paddle guard 30. Other embodiments may include a reinforcement portion 33 only at the outer paddle guard end 31.

[0061] Figure 3b Disclosed based on Figure 3a An enlarged view of the paddle stop 30 of the blade 10, wherein the reinforcement portion 33 is provided at each intersection position between the paddle stop 30 and one of the refiner teeth 20, and more specifically, at the corners of these intersection positions facing the first circumferential direction D, because these corners are the corners that are most worn due to the rotation of the blade 10 during use.

[0062] Figure 3cA sixth embodiment is disclosed that is similar to the fifth embodiment, except that at least some of the paddle stops 30 are subsurface paddle stops 30. The reinforcement portion 33 of the fifth embodiment may be included at at least one intersection of the paddle stop 30 with one of the refiner teeth 20, preferably at least the refiner tooth 20 at the outer paddle stop end 31. However, the reinforcement portion 33 is not shown in FIG. Figure 3c middle.

[0063] exist Figure 3a and Figure 3c In the embodiment of the present invention, the outer barrier end 31 of the first barrier 30 and the inner barrier end 32' of the second barrier 30' are connected to the same refiner tooth 20. The inner barrier end 32' of the second barrier 30' is closer to the inner periphery 11 than the outer barrier end 31 of the first barrier 30. This ensures that the transport of lignocellulosic material across the blade 10 is efficient and energy-saving.

[0064] exist Figure 3a to Figure 3c In the embodiment of the present invention, in a radial direction perpendicular to the first circumferential direction D, the outer barrier end 31 of the first barrier 30 and the outer barrier end 31 ″ of the adjacent barrier 30 ″ are each connected to a different refiner tooth 20. This means that there is an overlap of the barriers 30, 30 ″ in the first circumferential direction D at the outer barrier ends 31, 31 ″. In other words, the outer barrier end 31 of the first barrier 30 is offset from the outer barrier end 31 ″ of the adjacent barrier 30 ″ in the first circumferential direction D. The benefit of this arrangement is that the flow of lignocellulosic material and steam will cause wear on the barriers 30, 30 ″, in particular at the outer barrier ends 31, 31 ″, and by distributing the outer barrier ends 31, 31 ″ in this way, the wear on the blades is also greater than when the outer barrier ends 31 of a plurality of barriers 30 are connected to the same refiner tooth 20 or to each other as refiner teeth arranged as extensions (see, for example, Figure 2a ) is distributed more evenly.

[0065] Figure 4 An embodiment is disclosed wherein the density of refiner teeth 20 of each set of refiner teeth differs from the inner periphery 11 to the outer periphery 12. Furthermore, the paddle blocks 30 are shown as subsurface paddle blocks 30 and the grooves 50 are provided on the outer side 34 of each paddle block 30.

[0066] Figure 5 An embodiment is disclosed having an outer portion 15 which is arranged on the blade surface 13 between the refiner surface 14 and the outer periphery 12. In the outer portion 15, refiner teeth and a pulp stop are arranged for additionally refining the lignocellulosic material after it has passed the refining surface 14 with the refiner teeth 20 and the pulp stop 30 arranged according to the invention.

[0067] As mentioned above, the blade 10 may be a circular blade, but may alternatively be a blade section having a central angle of 10° to 360°. A plurality of blade sections may then be mounted in a refiner to form a circular blade.

[0068] The refining portion 14 may extend from the inner periphery 11 across the entire blade surface 13 to the outer periphery 12. Alternatively, there may also be other portions on the blade surface 13, such as those described above and Figure 5 14 and the outer portion 15 disclosed in the present invention. There may also be a portion comprising refiner teeth arranged between the refiner portion 14 and the inner periphery 11. Furthermore, there may be at least one portion on the blade surface 13 without refiner teeth, and such a portion may be arranged close to the inner periphery 11, close to the outer periphery 12 or at any other portion of the blade surface. Furthermore, in some embodiments, there may be two or more refiner portions 14 according to the invention on the blade surface 13, while another portion comprises refiner teeth or has no refiner teeth between them.

[0069] Figure 6 An embodiment of the present invention is disclosed which has no grooves 50 and in which the angle of the refiner teeth 20 varies across the blade 10 .

[0070] Figure 7a A groove 50 is shown adjacent to a paddle 30. The groove width w of the groove 50 is at least the width of the adjacent paddle 30, but may be significantly greater. In addition, the depth d of the groove 50 is at least half the paddle height of the adjacent paddle 30. Figure 7a In the embodiment, the groove width of the groove 50 is equal to the width of the adjacent paddle stop 30, and the depth d is also equal to half of the paddle stop height of the paddle stop 30. The depth d of the groove 50 is described with respect to the adjacent refiner tooth 20, that is, the refiner tooth 20 that begins to taper at the groove 50. Therefore, the depth d is the depth from the upper end of the adjacent refiner tooth 20, and the paddle stop height is the height from the tooth groove 40 adjacent to the paddle stop 30. Figure 7b A groove 50 is disclosed having a groove width w greater than the width of the paddle 30 and a depth equal to the paddle height of the paddle 30. In other embodiments, the size of the groove 50 may vary such that the groove width is equal to the depth, or alternatively, the groove width and depth differ from each other in any suitable manner as long as they are greater than Figure 7a The minimum dimensions shown are sufficient.

[0071] The present invention also relates to a refiner comprising at least one blade 10 according to any embodiment of the present invention disclosed herein. In some embodiments, the refiner may comprise two blades 10 according to the present invention, one of which is arranged as a rotor-side blade and the other as a stator-side blade. In other embodiments, one blade 10 according to the present invention may be arranged as a rotor-side blade or a stator-side blade together with a refiner blade according to the prior art.

[0072] It is to be noted that features from the various embodiments described herein may be freely combined, unless it is explicitly stated that such a combination would be inappropriate.

Claims

1. A blade for a refiner for refining lignocellulosic material, the blade (10) being delimited by an inner periphery (11) and an outer periphery (12) and comprising a blade surface (13), the blade surface having a refining portion (14), a plurality of refiner teeth (20) being arranged on the refining portion (14), wherein: Each refiner tooth (20) extends from an outer tooth end (21) to an inner tooth end (22), and wherein the plurality of refiner teeth (20) are arranged such that movement along the tooth extension from the outer tooth end (21) to the inner tooth end (22) of the refiner tooth (20) is also movement along a first circumferential direction (D), and wherein the blade (10) further comprises at least one paddle block (30) extending from the outer paddle block end (31) to the inner paddle block end (32) and connecting at least three refiner teeth (20), and wherein the paddle block (30) is further arranged such that movement along the paddle block extension from the outer paddle block end (31) to the inner paddle block end (32) is also movement along the first circumferential direction (D).

2. The blade according to claim 1, characterized in that The barrier height of the at least one barrier (30) is substantially equal to the tooth height of at least one of the refiner teeth (20) intersected by the barrier (30).

3. The blade according to claim 1, characterized in that The barrier height of the at least one barrier (30) is 20% to 99%, preferably 20% to 85%, of the height of at least one of the refiner teeth (20) to which the barrier (30) is connected.

4. The blade according to claim 2, characterized in that The blade further comprises at least one paddle (30) having a paddle height of 20% to 99%, preferably 20% to 85%, of the height of at least one of the refiner teeth (20) to which the paddle is connected.

5. A blade according to any one of the preceding claims, characterised in that The invention also comprises a groove (50) extending along the paddle stop (30) and adjacent to the paddle stop (30) on the outer side (34) of the paddle stop, wherein the outer side (34) is the side facing the outer periphery (12).

6. The blade according to claim 5, characterized in that The width of the groove (50) increases toward the inner pulp barrier end (32).

7. The blade according to claim 5 or 6, characterized in that: The width of the groove (50) at the upper end is at least equal to the width of the pulp stop (30).

8. The blade according to any one of claims 5 to 7, characterized in that The depth (d) of the groove (50) is at least equal to half the height of the pulp stop (30) adjacent to the groove (50), and the depth (d) is the depth from the upper end of the adjacent refiner tooth (20).

9. A blade according to any one of the preceding claims, characterised in that It also comprises a reinforcement portion (33), at which the outer pulp stop end (31) is connected to the refiner tooth (20), and the reinforcement portion (33) is arranged on a side of the pulp stop (30) facing the inner periphery.

10. A blade according to any one of the preceding claims, characterised in that The outer barrier end (31) of the first barrier (30) and the inner barrier end (32') of the second barrier (30') are each connected to the same refiner tooth (20), and the inner barrier end (32') of the second barrier (30') is closer to the inner periphery (22) than the outer barrier end (31) of the first barrier (30).

11. A blade according to any one of the preceding claims, characterised in that The outer blade end (31) of the first blade (30) and the outer blade end (31") of the radially adjacent blade (30") are each connected to different refiner teeth (20) along the first circumferential direction (D).

12. A blade according to any one of the preceding claims, characterised in that The blade (10) is a blade portion having a center angle of 10° to 360°.

13. A blade according to any one of the preceding claims, characterised in that Also included is at least one portion lacking refiner teeth.

14. A refiner for refining lignocellulosic material, the refiner comprising at least one blade according to any one of claims 1 to 13.

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