Refiner plate for a refiner and refiner

Abstract

Refiner plate (18) for a refiner (10) having one or more rotors (16) that is rotatable about an axis of rotation and cooperate with one of more stators (14) to mechanically treat a pulp containing cellulosic fibres, the refiner plates (18) being mountable to a rotor (16) or stator (14), the refiner plate (18) including: a base (22); and a plurality of spaced-apart refiner bars (30). At least some of the bars (30) are tilted with respect to the base (30) such that the leading edge of the bars (30) are essentially oriented in an acute angle (31) of less than 90° with respect to the base (22), preferably with an acute angle (31) of 50° to 80°, and most preferably with an acute angle (31) in the range of 60° to 70°.

Description

[0001] Refiner Plate for a Refiner and Refiner

[0002] TECHNICAL FIELD

[0003] The present invention relates generally to a refiner filling of a refiner for refining of cellulosic material in the manufacture of paper, paperboard, tissue, towel or fiberboard products and, more particularly, to the bars of the refiner filling as well as a refiner.

[0004] BACKGROUND

[0005] A rotary-type pulp refiner, which may be a disc-type refiner or a conical-type refiner, uses a replaceable refiner filling composed of refiner plates that are mounted to one or more rotors and one or more stators to mechanically shear and compress cellulosic fibres in a pulp suspension. The refiner plates may be one-piece (unitary) components or comprised of segments that are assembled together. The refiner plates have a plurality of refiner bars that perform the shearing and compressing actions on the cellulosic fibres in the pulp suspension. The spaces between the refiner bars in a plate define grooves through which the pulp suspension passes and which feed into gaps between the bars of opposing plates where the refining action is imparted. WO 2023 / 102642 discloses an embodiment of such a refiner having a refiner plate, which may be a unitary component or formed of a plurality of refiner plate segments.

[0006] In some examples, the bars are set at a distance to each other by means of spacers which are positioned between the bars. The bars and the spacers are generally perpendicular to the refining gap, or in other words, the bars extend essentially perpendicular with respect to a base of the refiner plate.

[0007] In both disc-type and conical refiners, the presence of abrasives in the pulp suspension accelerates the wearing of the refiner bars of the refiner filling, thereby decreasing the depth of the grooves between adjacent bars. As a consequence, the refiner filling usually needs to be replaced fairly frequently.

[0008] Although it is known to apply a wear-resistant coating to the leading surface of the bars to prolong service life, this coating occupies a significant portion of the groove volume between the refiner bars which, in turn, can reduce the hydraulic capacity of the refiner filling. WO 2023 / 102642 discloses a refiner plate with coatings. US 2024 / 0150962 A1 shows schematically profiled refining bars comprising profiled wire elements having a cross-section of inverted tilted T-shape. WO 2007 / 106294 A1 also discloses refiner plates having a plurality of elongate bars in different shapes.

[0009] Different materials, geometries and thicknesses of coatings on refiner bars have been considered in the prior art, but it is still desirable to provide refiner bars which provide a longer lifetime as well as reduced energy consumption during use. It is also advantageous to provide refiner bars that would have an improved corner on the leading edge to enhance fibre capture and with it the refining action and quality of the resulting fibre.

[0010] SUMMARY

[0011] It is the object of the present invention to provide an improved refiner and in particular an improved refiner bar design providing a longer lifetime, less energy consumption and enhanced pulp quality during use of the refiner.

[0012] The invention solves the aforementioned problem by providing a refiner plate for a refiner having one or more rotors that are rotatable about an axis of rotation and cooperate with one or more stators to mechanically treat a pulp containing cellulosic fibres, the refiner plates being mountable to a rotor or stator, the refiner plate including: a base and a plurality of spaced-apart refiner bars, wherein at least some of the bars are tilted with respect to the base such that the leading surfaces of the bars are essentially oriented at an acute angle of less than 90° with respect to the base in the range of 60° to 70°. In general, embodiments of the present invention provide a refiner plate and refiner in which the bars according to the claims are tilted (claim 1). The invention also solves the problem with a refiner having such refiner plates (claim 28).

[0013] In accordance with the invention, at least some of the refiner bars or all refiner bars are tilted, and the acute angle is in the range of 60° to 70°. By means of the tilted bars, more fibres are being captured, resulting in a more optimal fibre treatment, equating to less applied energy and hence the overall wear of the bars is reduced. It is not necessary to exchange the refiner plate as often as in the prior art. Further, energy consumption is reduced, because of the more efficient shearing action.

[0014] According to a second aspect of the invention (claim 2) there are spacers between the bars, and at least some of the spacers are tilted with respect to the base such that the spacers and base are essentially oriented at an acute angle of less than 90° with respect to each other, preferably with an acute angle of 50° to 80°, and most preferably with an acute angle in the range of 60° to 70°. If both the bars and spacers are tilted and oriented at an acute angle with respect to the base of the refiner plate in accordance with this aspect of the invention, the design is simple and efficient and easy to manufacture. In this preferred embodiment the bars and spacers extend essentially parallel with respect to each other.

[0015] In accordance with another preferred embodiment, the bars and / or spacers are integrally formed within the base, which results in a robust design and a low risk that individual bars loosen or detach from the base.

[0016] Further, it is preferred that downward sections of the bars are embedded in a solidified material, wherein preferably the material is a layer and / or is formed of liquid epoxy, molten metal or some other fluid material that becomes a solidified material. This results in a tight connection.

[0017] According to a further aspect of the invention (claim 8), not all tilted bars aretilted at the same angle. This concept of a variation of angles of bars, for example, results in the advantage that tilted bars would be set at an optimal acute angle with respect to the local tangential velocity. For example, the acute angle of bars closer to the outer diameter of the refiner plate may be less than bars closer to the inner diameter of the refiner plate. Another strategy that could be applied using this alternative, preferred aspect of the invention or embodiment would be to increase the diversity of refining actions by mixing the acute angles of bars circumferentially. A pulp suspension contains fibres of various lengths and diameters and an increased heterogeneity of fibre properties may benefit the resultant properties of the refined pulp. In accordance with this aspect of the invention, it is possible that not all bars of the refiner plate need to be tilted in an acute angle and that some bars of the refiner plate can be oriented in a 90° angle.

[0018] In another alternative, preferred embodiment, more than 10% of the bars have an angle of 90° with respect to the base. In other words, not all bars are tilted, but only a fraction of all bars. This results in the aforementioned advantage of suiting the optimal bar angle radially to the local tangential velocity, or in creating a diversity of refining actions circumferentially. Bars with an angle of 90°, also called a right angle, may also provide benefits from a structural or manufacturing perspective in being less costly to create or to provide increased structural strength.

[0019] According to a preferred embodiment, the tilt angle of the refiner bars is increasing within a section of the refiner plate, with the result that the shearing action applied to the fibers by means of the bars differs in view of the increasing tilt angle. A progressively-greater (tilt) angle circumferentially may serve to create an optimal, progressive, refining action whereby the initial bar-crossing, with the lower angle is more effective in capturing fibers, while the following bar-crossing, with the slightly greater angle, that follows in quick succession, benefits from the preceding fiber accumulation, but provides a more effective refining action, and so on for the following bar crossings. The net effect is to enhance the quality of the refined pulp.

[0020] Another preferred embodiment is characterized in that the refiner plate has different sections, and the tilt angle of the refiner bars is different in the different sections radially. This may create the following effects: While the flows within a refiner are complex, the bulk flow is generally outward radially. One possible embodiment would be to apply a relatively aggressive action with a higher angle initially, i.e. at a section near the inner radius. Then, for the pulp that has already been partially refined, and which is moving to a more outer radius, where the local circumferential velocity is naturally increased, to use a lower angle which emphasizes increased bar-edge accumulation and a less aggressive refining action. The net overall effect is to enhance pulp quality for a given energy input.

[0021] In accordance with another preferred embodiment, the tilt angle of the refiner bars in at least one of the different sections is essentially the same. Maintaining the same tilt angle circumferentially of the bars in a particular section may be advantageous either from the perspective of manufacturing efficiency or in order to maximize the local refining effect at that particular radius and local circumferential velocity.

[0022] Further, it is preferred that the tilt angle of refiner bars decreases radially outwardly with respect to an axis of rotation of a rotor comprising the refiner plate. This strategy may be particularly advantageous in order to modify the refining action for pulp which has already been somewhat refined, given the generally outward bulk flow, and is moving towards the exit of the refining zone at the outer periphery. It may also be beneficial given that the circumferential velocity is lowest at the inner radius, and a higher tilt angle may compensate for the lower circumferential velocity.

[0023] Another alternative embodiment is characterized in that at least one bar oriented in a rectangular angle (90°) and at least some of the bars are tilted with respect to the base in a tilted way in an acute angle, preferably such that the leading surface of the tilted bars is essentially oriented in an acute tilt angle of less than 90° with respect to the base. A bar with a rectangular or right angle (90°) will provide the greatest strength in the event of refiner plate clashing, which is the state when the two refiner plates move together and touch. In such a design the tilted bars may provide the optimal refining action while the rectangular bars will increase the mechanical strength and robustness of the refiner plate.

[0024] Further, it is preferred that a plurality of bars is oriented at a rectangular angle in one section and a plurality of bars is tilted at an acute angle with respect to the base within an adjacent section of the refiner plate. The preferred effects of such a design follows on the aforementioned strategy of having a single rectangular angle blade, however having a full section of rectangular blades could be simpler to manufacture, and would provide additional mechanical strength. The additional strength may be especially important near the inner radius, for example, given that this is where the pulp enters the refining zone and the incoming pulp may have tramp materials such as rocks or metal pieces. A more robust local design may be important in resisting the effects and potential damage of these hard contaminants. Another preferred embodiment is characterized in that the bars and / or spacers are attached to the base by means of brazing, welding, press-fitting or gluing, as all these manufacturing methods are relatively simple and provide good strength.

[0025] A further preferred embodiment is characterized in that the bars and / or spacers have a trapezoidal shape in cross-section which results in a robust design and is relatively easy to manufacture, for example by means of machining processes.

[0026] Further, it is preferred that at least some of the above bars have a leading edge being defined by an acute angle between the surrounding outer and leading surfaces, preferably wherein the most outward surface of the bar is oriented essentially parallel to the base. This embodiment is developed further in that a trailing edge is defined by an obtuse angle between the surrounding outer and trailing surfaces.

[0027] In accordance with another preferred embodiment, spacers have an inclined upper surface and an inclined lower surface. The inclined upper surface may be advantageous in maximizing the groove area between the bars which is a strong determinant of overall refiner capacity. It may also be advantageous in avoiding the creation of recirculating zones within the groove that could develop and reduce the effective groove area. A benefit of the inclined lower surface may be manufacturing efficiency, where the spacers may be created by shearing sheet metal, which would create a lower surface that is at a right angle to the side of the spacer.

[0028] Advantageous effects are achieved in an embodiment in which spacers have a horizontal upper surface and an inclined lower surface. The horizontal upper surface may, as discussed previously, provide a further increase the groove area relative to the aforementioned inclined upper surface and, in situations where recirculating zones are of less concern, a net increase to refiner capacity.

[0029] Other effects are achieved according to an embodiment in which spacers have an inclined upper surface and a horizontal lower surface. The horizontal lower surface may be beneficial from a structural and manufacturing perspective. Structural strength may be increased by having a large contact area between the spacer and the base to enhance the means of bonding between the spacer and base. Manufacturing may also be facilitated by using the base as a restraint that the blades assist in the positioning of the blades during assembly.

[0030] Finally, if according to a preferred embodiment, the spacers have an inclined upper surface and a horizontal lower surface, the shearing action is further improved. As discussed previously, the complex flows within the groove and potential for the formation of recirculating zones within may determine alternate optimal designs depending on the bar and grooves widths, the types of fibers to be treated, and the local circumferential velocities.

[0031] Still another preferred embodiment resulting in a robust design is characterized by having the bars positioned and press-fitted and / or glued within slots formed within a slotted support plate that may then act as a base, wherein the distance of the slots defines the distance between the bars. Preferably, the bars may protrude upwardly and downwardly from the slotted support plate.

[0032] Preferably the base, bars and spacers are made of metal and at least some of the refiner bars have a surface coated with a coating, preferably a coating having a variable coating thickness that varies along the bar length. Metal provides a high strength, and the coating may improve the wear characteristics of the refiner plate. In accordance with a preferred embodiment, the base, bars and spacers are made of dissimilar metals.

[0033] Another preferred embodiment of the refiner is characterized by a stator having a plurality of rectangular refiner bars and a rotor having a plurality of tilted refiner bars. There may well be manufacturing efficiencies in having either the rotor or the stator made with a plurality of rectangular refiner bars, which may be a simpler method of construction. While having a plurality of tilted refiner bars on one of the refiner plates, be it either the rotor or stator, may benefit fiber capture and the refining action, the optimal effect may occur in the combination of a tilted bar being opposed by a rectangular bar in the bar crossing gap where the refiner action occurs. The foregoing presents a simplified summary of the invention with its different aspects or preferred embodiments in order to provide a basic understanding of some aspects of the invention. This summary is not an exhaustive overview of the invention. It is not intended to identify essential, key or critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed below.

[0034] BRIEF DESCRIPTION OF DRAWINGS

[0035] Other aspects of the invention are defined in the claims and described below in relation to the accompanying drawings, in which:

[0036] FIG. 1 is a perspective view of a refiner having a rotor and stator in accordance with an embodiment of the present invention showing the replacement of a segment of the refiner plate on the mounting surface of the stator.

[0037] FIG. 2 is another perspective view of the refiner of FIG. 1 showing the replacement of a segment of the refiner plate on the mounting surface of the rotor.

[0038] FIG. 3 is a cross-sectional view of a refiner plate segment according to the prior art.

[0039] FIG. 4 is a cross-sectional view of a refiner plate segment according to one embodiment of the invention.

[0040] FIG. 5 is a cross-sectional view of a refiner plate segment according to another embodiment of the invention.

[0041] FIG. 6 is a cross-sectional view of a refiner plate segment according to another embodiment of the invention.

[0042] FIG. 7 is a cross-sectional view of a refiner plate according to another embodiment of the invention. FIG. 8 is a cross-sectional view of a refiner plate according to another embodiment of the invention.

[0043] FIG. 9 is a cross-sectional view of a refiner plate according to another embodiment of the invention.

[0044] FIG. 10 depicts a prior art design.

[0045] FIG. 11 depicts a design according to the invention in operation;

[0046] FIG. 12 is a view of another embodiment of a refiner plate having tilted refiner bars with different tilt angles in a generally circumferential orientation.

[0047] FIG. 13 is a cross section of the refiner plate of Fig. 12 having tilted refiner bars with different tilt angles.

[0048] FIG. 14 is a view of another embodiment of a refiner plate segment having tilted refiner bars with different tilt angles in different clusters in a generally radial orientation.

[0049] FIG. 15 is a cross section of the refiner plate segment of Fig. 14 having tilted refiner bars with different tilt angles at different sections A-A, B-B, C-C.

[0050] FIG. 16 is a view of another embodiment of a refiner plate having tilted refiner bars with different tilt angles in a generally circumferential orientation.

[0051] FIG. 17 is a cross section of the refiner plate of Fig. 16 him having tilted refiner bars with different tilt angles.

[0052] FIG. 18 is a view of another embodiment of a refiner plate having tilted refiner bars with different tilt angles in different sections. FIG. 19 is a cross section of the refiner plate of Fig. 18 having tilted refiner bars with different tilt angles at different sections F-F, G-G in a generally circumferential orientation.

[0053] FIG. 20 is a cross section of another embodiment of a refiner plate having tilted refiner bars and spacers with an inclined upper surface and an inclined lower surface.

[0054] FIG. 21 is a cross section of another embodiment of a refiner plate having tilted refiner bars and spacers with a horizontal upper surface and an inclined lower surface.

[0055] FIG. 22 is a cross section of another embodiment of a refiner plate having tilted refiner bars and spacers with an inclined upper surface and horizontal lower surface.

[0056] FIG. 23 is a cross section of another embodiment of a refiner plate having tilted refiner bars and spacers with an inclined upper surface and horizontal lower surface.

[0057] FIG. 24 is a side view on a stator having a plurality of rectangular refiner bars and rotor having a plurality of tilted refiner bars.

[0058] FIG. 25 is a cross-sectional view of the stator having a plurality of rectangular refiner bars and rotor having a plurality of tilted refiner bars according to the embodiment shown in FIG. 24.

[0059] DETAILED DESCRIPTION

[0060] FIG. 1 is a perspective view of a refiner 10 in accordance with one embodiment of the present invention. The refiner 10 has a housing 12, a stator 14 and a rotor 16 within the housing 12. The rotor 16 is rotatable and in-use rotates about an axis of rotation X and cooperates with the stator 14 to mechanically treat a pulp (or pulp suspension) containing cellulosic fibres. The axis of rotation X defines an axial direction and a radial direction perpendicular to the axial direction X. In the illustrated embodiment of FIG. 1 , the refiner 10 is a disc-type refiner 10 having a replaceable refiner plate 18 including a refiner plate segment 20. Other types of refiners 10 may have the design of the refiner plate 18 in accordance with the embodiments of the invention. A mounting surface exists on each of the rotor 16 and stator 14. In some cases an adaptor plate will be bolted onto the mounting surface to receive smaller refiner plate segments. The refiner plate segments 20 will typically have a base which receives the bolts so that the refiner plate segment 20 can be bolted onto the mounting surface.

[0061] It is noted that all embodiments shown show design examples, but the embodiments shown are not necessarily shown to scale or in exact manufacturing dimensions. Rather, the dimensions can be varied, as the skilled person understands.

[0062] The bars 30 (sometimes referred to as blades) may be joined with spacers 24 by welding or brazing to form a cluster, which will then be welded to the base, and in some cases to a frame, to which form the refiner plate segment. Alternatively, the bars 30 may be inserted into a slotted base and retained by either welding, a press- fit, gluing or some other means to form the cluster. In another option, the bars will be inserted into a slotted support plate described further below and extended into a solidified medium that will form the base.

[0063] The complete refiner plate 18 is preferably composed of a plurality of refiner plate segments 20, but the refiner plate 18 may also be a unitary single-piece design. In the example of FIG. 1 , the refiner plate 18 is comprised of segments 20. A refiner plate 18 is a generally flat, annular disc-like or plate-like structure. It will be appreciated that in accordance with alternative embodiments of the invention, the refiner plate 18 may be a conical structure in a conical refiner. The expression refiner plate 18 shall be construed as encompassing a flat disc-like plate containing an arcuate segment 20 thereof, or a conical structure or an angular segment thereof. For a disc-type refiner, the refiner plate may be a one-piece circular plate, or an annular plate comprising arcuate segments that are assembled with other arcuate segments to form the complete circular or annular plate. For a conical refiner, the refiner plate may be a one-piece conical (or frusto-conical) structure or a conical structure comprising angular segments of a cone (or frustum) that are assembled to form a complete conical (or frusto-conical) structure. It is to be understood that a refiner plate 18 may be circular, annular or conical (i.e. defining a complete 360-degree component) or segmented (i.e. defining an arcuate or angular component of less than 360 degrees that is designed to be assembled with other such segments to form the complete circular or annular plate or to form the cone, as the case may be).

[0064] FIG. 1 depicts the refiner plate 18 on the stator 14 and the replacement refiner segment 20. The refiner plate segment 20 may be mounted to the stator 14 using fasteners, e.g. threaded screws or bolts, as shown. In this example, a plurality of refiner plates segments 20 are mounted to the stator 14 in an annular arrangement to constitute a complete ring-shaped stator-side refiner plate 18. As illustrated in FIG. 1 , the stator 14 is mounted to a door-like cover 15 that pivots about a hinge mechanism to enable replacement of the refiner plate(s) 20. Cover 15 cooperates with the housing 12.

[0065] FIG. 2 is another perspective view of the refiner 10 of FIG. 1 showing the refiner plate 18 on the rotor 16 and the replacement segment 20 thereof. The refiner plate segment 20 may be mounted to the rotor 16 using fasteners, e.g. threaded screws or bolts, as shown. A plurality of refiner plate segments 20 are mounted to the rotor 16 in an annular arrangement to constitute a complete ring-shaped rotor-side refiner plate 18. The rotor 16 is mounted inside the housing 12 of the refiner 10 and driven by a motor, preferably an electric motor. As mentioned, the refiner plates 18 may be one-piece (unitary) components or refiner plate segments 20 that are assembled together to form a complete refiner plate, such as a ring-shaped refiner plate 18. When servicing the refiner, the refiner plate 18 may be replaced, if worn, by replacing the assembly of refiner plate segments 20 that constitute the complete plate 18. FIG. 1 shows that the complete annular refiner plate 18 may be characterized by an inner diameter (ID) and an outer diameter (OD). The refiner plate thus extends radially from the inner diameter to the outer diameter. It will also be appreciated that a complete plate or annulus of arcuate or segmented filling pieces may be composed of filling pieces of different shapes. As illustrated in FIGS. 3 - 11 , a refiner plate 18 has a base 22. The base 22 may have a uniform thickness in an axial direction in some embodiments although it may alternatively have a non-uniform thickness. The base 22 extends radially from an inner diameter ID to an outer diameter OD as depicted in FIG. 1 . As shown, the refiner plates 18 have a plurality of refiner bars 30 that perform the shearing and compressing actions on the cellulosic fibres in the pulp suspension. The prior art refiner plates 18 shown in FIGS. 3 and 10, and in particular the refiner plates 18 in accordance with the invention illustrated in particular in FIGS. 4 - 9 and 11 have refiner bars 30 protruding from a base 22. With respect to the prior art, for example disclosed in WO 2023 / 102642, the bars 30 or spacers 24 are perpendicular to a base 22, meaning that they extend essentially perpendicular in a right (90°) angle with respect to a base 22 of the refiner plate 18.

[0066] As shown in FIGS. 4 - 9 and 11 , the refiner plates 18 according to the embodiments of the invention have a plurality of spaced-apart refiner bars 30 (also known as “blades”). The bars 30 may be spaced apart with a uniform or non- uniform groove width, i.e. the spacing between adjacent bars may vary or be constant. Preferably, the refiner bars 30 are spaced apart by spacers 24. Each bar 30 is defined by a bar height BH protruding generally axially from the base / spacer structure. The bar height BH may be constant or varying, with the variation occurring from statorto rotor, along the length of the groove, from groove to groove or from one side of the groove to the other. In general, the bar height BH is in the range of 0.5 to 14.0 mm when new and 0 to 2.0 mm when worn. In some implementations, the bar width BW may be, for example, a value that is within the range of 0.5 to 7.0 mm.

[0067] FIGS. 4 - 9 and 11 illustrate various embodiments of a refiner plate 18 having refiner bars 30 that are tilted and extend at an acute tilt angle 31 with respect to the base 22 and / or direction of the relative movement or direction of rotation (see in particular FIG. 11. The refiner bars 30 have a leading surface 39 and leading edge 32 and a radially-outward surface 36 and trailing surface 38 and trailing edge. Leading surface 39 and trailing surface 38 in this context means with respect to the direction of movement, in particular the direction of rotation 52 of the refiner plate 18 shown in FIG. 11 , or related to direction of movement between the stator 14 and rotor 16. The spaces between the refiner bars define grooves 34 through which the pulp suspension passes during use, and which feed into the gaps between the radially-outward areas 36 of the bars of the refiner plates on the rotor and stator.

[0068] As shown in the embodiments according to the invention, all bars 30 or at least some of the bars 30 are tilted with respect to the base 22. Preferably, they are tilted such that the leading surface 39 of the bars 30 is essentially oriented in an acute angle 31 of less than 90° with respect to the base 22 and / or its upward surface; preferably with an acute angle of 50° to 80°; and most preferably with an acute angle in the range of 60° to 70°.

[0069] It is apparent from the figures, that all or at least some of the bars 30 have a leading surface 39 with a leading edge 32 that serves as a vertex defining an acute angle 31 between the surrounding leading and outer bar surfaces. Preferably, the outer surface 36 of the bar is oriented essentially parallel to the base 22 or an outward surface of the base 22.

[0070] The trailing surface 38 has a trailing edge that serves as a vertex defining an obtuse angle 33 between the surrounding trailing and outer bar 22 surfaces.

[0071] As shown in figures, it is preferred that also all or at least some of the spacers 24 are tilted with respect to the base 22 such that the spacers 24 and base 22 are essentially oriented at an acute angle 31 of less than 90° with respect to the base 22, preferably with an acute angle of 50° to 80°, and most preferably with an acute angle in the range of 60° to 70°. This results in a configuration in which the bars 30 and spacers 24 extend essentially parallel to each other.

[0072] The bars 30 and / or spacers 24 are preferably attached to the base 22 by means of welding, brazing, press-fitting or gluing or other manufacturing methods. In a not-shown embodiment also in accordance with the invention, the skilled person will understand that it is also possible that the bars 30 and / or spacers 24 are integrally-formed within the base 22 or integrally-formed with the base 22. It is preferred that at least 10% of the bars have an angle of 90° with respect to the base 22. In the shown embodiment according to FIGS. 4 - 9 and 11 , all bars 30 form an acute angle 31 with respect to the base 22.

[0073] In the embodiment shown in FIG. 4, the spacers 24 in cross-section are rectangular. A spacer void 35 is formed between the lower surface of a spacer 24 and surface of base 22. Also, as the lower section of each bar 30 in cross-section have a rectangular shape, a bar void 37 is formed between the lower surface of a bar 30 and surface of base 22.

[0074] In the embodiment shown in FIG. 5, each spacer 24 in cross-section has a trapezoidal shape, so that the lower surface of a spacer 24 is in contact with the upper surface of the base 22. As the lower section of each bar 30 in cross-section has a rectangular shape, a bar void 37 is formed between the lower surface of a bar 30 and surface of base 22.

[0075] As is apparent from the exemplary embodiment shown in FIG. 6, the bars 30 and spacers 24 may have a trapezoidal shape in cross-section. In this configuration, the lower surfaces of both the spacers 24 and the bars 30 are in contact with the upper surface of the base 22.

[0076] The voids 35, 37 or contact surfaces between bars 30 and / or spacers 24 and / or base 22 may be filled with adhesive material or filling or sealing material. This material can be, for example, an epoxy, or solidified molten metal, or an elastopolymer that has passed from a liquid to solidified state.

[0077] As is, in particular, apparent from the configuration according to the embodiment shown in FIG. 7, the bars 30 may be positioned within slots 40 formed within a slotted support plate 42, which is preferably attached to the base 22. Slots 40 essentially extend in parallel to each other and with an acute angle 31 of less than 90°, as shown in FIG. 7 with respect to the base 22. Thus the bars 30, which with their lower portion are within the slots 40, are also oriented at an acute angle 31 with respect to the support plate 42 and base 22. A trailing edge defined by the trailing surface 38 and outer surface of the bars 30 is the vertex of an acute angle of less than 90° in the example which is the same as angle 31 , preferably in the range of 50° to 80°, and most preferably with an acute angle 31 in the range of 60° to 70. Preferably, the support plate 42 is bolted, welded or glued to base 22. Bars

[0078] 30 are preferably press-fitted and / or glued within the slots 40 formed within the slotted support plate 42 attached to base 22. The distance D of the slot spacing 40 defines the spacing of the bars 30.

[0079] The embodiment shown in FIG. 8 is essentially the same as the embodiment in FIG. 7 with the difference that in FIG. 8 the bars 30 extend both upwardly and downwardly from the slotted support plate 42. The downward sections or extensions of the bars 30 are embedded in a solidified material, preferably an epoxy or solidified molten metal layer 43 that secures bars 30 and reinforces the overall structure of the refiner plate 18.

[0080] In the embodiment shown in FIG. 9, the bars 30 have been located relative to the spacers 24 and base 22 as shown in the prior art embodiment in FIG. 3, but the bars 30 have been bent for part of their length extending beyond the spacers 24 in order to create the acute angle 31. As such, the bar need not have a simple rectangular shape in cross-section and the exposed bar height is what is critical to the improved action of the invention.

[0081] FIG. 10 illustrates the complete configuration with a prior art configuration showing the direction of rotation of the rotor relative to the stator and the gap 50 between the opposing radially-outward surfaces 36 of the bars 30.

[0082] Fig. 11 illustrates the complete configuration with the bars 30 set at an acute angle

[0083] 31 relative to the base 22, and the bars 30 acting to provide the enhanced shearing and refining actions, based on the rotation of the rotor 16 and in cooperation with stator 14.

[0084] Preferably, base 20 and bars 30 and spacers 24 and support plate 42 are made of metal. Figs. 12 - 25 show alternative embodiments of refiner plates 18 or refiner plate segments 20 for use in a refiner 1 , which are fundamentally identical or similar in design to the previously described embodiments described with reference to Figs. 1 to 11 . Where identical or similar or functionally equivalent components are used, reference is made in full to the above descriptions of the embodiments, which apply equally and analogously to the embodiments described in the following; additional features, functions and differences are described essentially below. Also, identical or similar or functionally equivalent components or features have the same reference numerals as used in the previous descriptions to which reference is made in full content.

[0085] FIG. 12 and 13 show an embodiment of a refiner plate 18 or refiner plate segment 20 for use in a refiner 1. FIG. 13 is a cross section of the refiner plate of Fig. 12 having tilted refiner bars with different tilt angles. The complete refiner plate 18 is preferably composed of a plurality of refiner plate segments 20, but the refiner plate 18 may also be a unitary single-piece design. In the example, the refiner plate 18 is comprised of segments 20. The refiner plate 18 has a base 22 and a plurality of spaced-apart refiner bars 30, which preferably are spaced apart by spacers 24. Refiner bar 30 is oriented in a right or rectangular angle 25 or perpendicular or in a 90° angle with respect to base 22 or direction of movement 52; the refiner be 30 is not tilted, rather an additional bar with respect to the following described tilted bars. The refiner bars 30.1 , 30.2, 30.3, 30.4 are tilted and extend at an acute angle 31 with respect to the base 22 and / or direction of the relative movement or direction of rotation 52. The refiner bars 30.1 , 30.2, 30.3, 30.4 are tilted with different tilt angles 31.1 , 31.2, 31.3, 31.4 in a generally circumferential orientation, as can be seen in Fig. 13. Tilt angles are approximately 31.1 = 83°, 31.2 = 75°, 31.3 = 65°, 31 .4 = 65°. It is to be understood that these tilt angles are just examples and can be varied in accordance with the invention. Spacers 24.1 , 24.2, 24.3, 24.4, 24.5 are positioned between bars 30, 31.1 , 31.2, 31.3, 31.4 and have a lower height extending upwardly from base 22 compared to bars 30, 31.1 , 31.2, 31.3, 31.4. resulting in bar height BH. Spacers 24.1 , 24.2, 24.3, 24.4, 24.5 have horizontal and parallel upper and lower surfaces, and preferably the side surfaces are in contact with the side surfaces of the respective refiner bars 30.1 , 30.2, 30.3, 30.4. FIG. 14 and FIG. 15 show another embodiment of a refiner plate segment 20 of a refiner plate 18 (Fig. 1) having tilted refiner bars 30, 30.1 , 30.2 with different tilt angles 30.1 , 30.2 in different sections A-A, B-B, C-C, preferably in a generally radial orientation. FIG. 15 shows cross sections of the refiner plate segment 20 of Fig. 14 having tilted refiner bars 30.1 , 30.2 with different tilt angles 31.1 , 31.2 at the different sections A-A, B-B, C-C (Fig. 14) of the refiner plate segment 20, as can be seen in Fig. 14. Refiner bars 30 in section A-A are oriented at a right angle or perpendicular or at a 90° angle 25 with respect to base 22or direction of movement 52. Tilt angles are approximately 31.1 = 83°, 31.2 = 65°. It is to be understood that these tilt angles are just examples and can be varied in accordance with the invention. Spacers 24.1 , 24.2, 24.3 are positioned between bars 30, 31.1 , 31.2, in the sections A-A, B-B, C-C and have a lower height extending upwardly from base 22 compared to bars 30, 31 .1 , 31 .2 resulting in bar height BH. Spacers 24.1 24.2, 24.3 have horizontal and parallel upper and lower surfaces, and preferably the side surfaces are in contact with the side surfaces of the respective refiner bars 30, 30.1 , 30.2. Spacers 24.1 have a square cross- sectional shape, and spacers 24.2, 24.3 have a trapezoidal cross-sectional shape in accordance with the respective tilt angle 31.1 , 31 .2.

[0086] FIG. 16 and Fig. 17 are views of another embodiment of a refiner plate 18 or refiner plate segment 20 having tilted refiner bars 30, 31.1 with different tilt angles 30,

[0087] 30.1 , preferably in a generally circumferential orientation. FIG. 17 is a cross section D-D of the refiner plate segment 20 of Fig. 16 having tilted refiner bars with different tilt angles 30, 30.1. Refiner bar 30 (left side) is oriented at a right angle 25 or perpendicular or in a 90° angle 25 with respect to base 22 or direction of movement 52. Tilt angles 31.1 of bars 30.1 = 65°. It is to be understood that these tilt angles are just examples and can be varied in accordance with the invention. Spacers

[0088] 24.1 , 24.2, 24.3 are positioned between bars 30, 31.1 and have a lower height extending upwardly from base 22 compared to bars 30, 31 .1 , 31 .2 resulting in bar height BH. Spacers 24.1 24.2, 24.3, 24.4 have horizontal and parallel upper and lower surfaces, and preferably the side surfaces are in contact with the side surfaces of the respective refiner bars 30, 30.1. FIG. 18 and FIG. 19 are views of another embodiment of a refiner plate having tilted refiner bars with different tilt angles in different sections. FIG. 19 is a cross section of the refiner plate of Fig. 18 having tilted refiner bars with different tilt angles at different sections F-F, G-G, preferably in a generally circumferential orientation. Refiner bars 30 (four on left side) in Section F-F are all oriented in a right angle 25 or perpendicular or at a 90° angle with respect to base 22 or direction of movement 52. The refiner bars 30.1 in section G-G (four on right side in Fig. 18) are all tilted at an acute angle 31.1 with respect to the base 22 and / or direction of the relative movement or direction of rotation 52. Tilt angles 31.1 of bars 30.1 = 65°. It is to be understood that these tilt angles are just examples and can be varied in accordance with the invention. Spacers 24.1 in section F-F are having a square cross-sectional shape and are positioned between bars 30. Spacers 24.2 in section G-G have horizontal and parallel upper and lower surfaces, and preferably the side surfaces are in contact with the side surfaces of the respective refiner bars 30.1 .

[0089] Fig. 20 - 23 show refiner plates 18 or refiner plate segments 20 having bars 30.1 with an acute tilt angle of approximately 65° with respect to base 22. It is to be understood that these tilt angles are just examples and can be varied. Essentially the shape of the spacers 24 vary in the different shown embodiments.

[0090] FIG. 20 shows a spacer 24.1 with an inclined upper surface decreasing in the direction opposite to the direction of the relative movement 52 and an inclined lower surface 27.1 , resulting in a spacer void 35 between spacer 24.1 and base 22. The side surfaces of spacers 24.1 are in contact with the bars 30.1 . As the lower section of each bar 30.1 in cross-section has a rectangular shape, a bar void 37 is formed between the lower surface of a bar 30.1 and surface of base 22. The refiner bars 30.1 are all tilted at an acute angle 31.1 with respect to the base 22 and / or direction of the relative movement or direction of rotation 52. Tilt angles 31.1 of bars 30.1 = 65°. It is to be understood that these tilt angles are just examples and can be varied.

[0091] FIG. 21 is a cross section of another embodiment of a refiner plate segment 20 having tilted refiner bars 30.1. The shown embodiment is identical with the embodiment shown in Fig. 20, with the only difference that the spacers 24.2 have a horizontal upper surface 28 instead of an inclined upper surface 26.1. We fully refer to the above description regarding the embodiment shown in Fig. 20.

[0092] FIG. 22 is a cross section of another embodiment of a refiner plate segment 20 having tilted refiner bars 30.1 and spacers 24.3 with an inclined upper surface 26.2 and horizontal lower surface 29 in direct contact with the upper surface of base 22, so there is no spacer void 35. The side surfaces of spacers 24.3 are in contact with the bars 30.1. As the lower section of each bar 30.1 in cross-section has a rectangular shape, a bar void 37 is formed between the lower surface of a bar 30.1 and surface of base 22. The refiner bars 30.1 are all tilted at an acute angle 31.1 with respect to the base 22 and / or direction of the relative movement or direction of rotation 52. Tilt angles 31.1 of bars 30.1 = 65°. It is to be understood that these tilt angles are just examples and can be varied.

[0093] FIG. 23 is a cross section of another embodiment of a refiner plate segment 20 having tilted refiner bars 30.1 and spacers 24.4 with an inclined upper surface 26.3 and horizontal lower surface 29 in direct contact with the upper surface of base 22, so there is no spacer void 35. The inclined upper surface 26.3 is inclined such that the distance from the base 22 increases with the direction of a relative movement 52. The side surfaces of spacers 24.4 are in contact with the bars 30.1. As the lower section of each bar 30.1 in cross-section has a rectangular shape, a bar void 37 is formed between the lower surface of a bar 30.1 and surface of base 22. The refiner bars 30.1 are all tilted at an acute angle 31.1 with respect to the base 22 and / or direction of the relative movement or direction of rotation 52. Tilt angles 31.1 of bars 30.1 = 65°. It is to be understood that these tilt angles are just examples and can be varied.

[0094] FIG. 24 is a side view on a stator 14 having a plurality of rectangular refiner bars 30 and rotor 16 having a plurality of tilted refiner bars 30.6. FIG. 25 is a cross- sectional view of the stator 14 having the plurality of rectangular refiner bars 30 and rotor 16 having a plurality of tilted refiner bars 30 according to the embodiment shown in FIG. 24, which are spaced by spacers 24 having a generally rectangular cross-section (Fig. 25). The general arrangement of stator 14 and rotor 16 is shown in Fig. 1. Fig. 24 and Fig. 25 show the relation of stator 14 having refiner bars 30 which are oriented in an 90° angle 25 with respect to the base 22 and a rotor 16 having tilted refiner bars 30.6 which are oriented in an acute angle 31.5 with respect to the base 22 of the rotor.

[0095] Stator 14 has a base 22 and spacers 24having a general rectangular cross-section. Between the spacers 24 of stator 14 are the bars 30. Refiner bars 30 are oriented at a right angle 25 or perpendicular or at a 90° angle with respect to base 22. The rotor 16 has a base 22 and a plurality of spaced-apart refiner bars 30.6, which preferably are spaced apart by trapezoidal spacers 24.6. The refiner bars 30.6, are tilted and extend at an acute angle 31 with respect to the base 22 and / or direction of the relative movement or direction of rotation 52.

[0096] As it is not shown in detail, all described embodiments according to the invention may be configured such that at least some of the refiner bars have a surface coated with a coating, preferably a coating having a variable-coating thickness that varies along the bar height. For details of the coating, it is referred to WO 2023 / 102642 of the applicant, whose disclosure is fully incorporated into this application by reference. A variable-coating has a coating thickness that is variable along either the height of the refiner bar (e.g. increasing from the base to the top of the bar) or variable in the radial direction (e.g. increasing from the inner diameter ID to the outer diameter OD of the filling, see FIG. 1).

[0097] This invention has been described in terms of specific embodiments, implementations and configurations which are intended to be exemplary only. Persons of ordinary skill in the art will appreciate that many obvious variations, refinements and modifications may be made without departing from the inventive concept(s) presented in this application. For example, the term refiner plate covers a refiner plate segment. The scope of the exclusive right sought by the applicant is therefore intended to be limited solely by the appended claims. - ZZ -

[0098] Reference numerals:

[0099] 10 refiner

[0100] 12 housing

[0101] 14 stator

[0102] 15 cover

[0103] 16 rotor

[0104] 18 refiner plate

[0105] 20 refiner plate segment

[0106] 22 base

[0107] 24 spacer

[0108] 24.1 spacer

[0109] 24.2 spacer

[0110] 24.3 spacer

[0111] 24.4 spacer

[0112] 24.5 spacer

[0113] 24.6 spacer

[0114] 25 right or rectangular angle (90°)

[0115] 26.1 inclined upper surface of spacer

[0116] 26.2 inclined upper surface of spacer

[0117] 26.3 inclined upper surface of spacer

[0118] 27.1 inclined lower surface of spacer

[0119] 28 horizontal upper surface of spacer

[0120] 29 horizontal lower surface of spacer

[0121] 30 refiner bar

[0122] 30.1 refiner bar

[0123] 30.2 refiner bar

[0124] 30.3 refiner bar

[0125] 30.4 refiner bar

[0126] 30.5 refiner bar

[0127] 30.6 refiner bar

[0128] 31 acute angle or tilt angle

[0129] 31.1 acute angle or tilt angle

[0130] 31 .2 acute angle or tilt angle 31 .3 acute angle or tilt angle

[0131] 31 .4 acute angle or tilt angle

[0132] 31.5 acute angle or tilt angle

[0133] 32 edge

[0134] 33 obtuse angle

[0135] 34 groove

[0136] 35 spacer void

[0137] 36 axial-outward surface

[0138] 37 bar void

[0139] 38 trailing surface

[0140] 39 leading surface

[0141] 40 slot

[0142] 42 slotted support plate

[0143] 43 solidified layer

[0144] 50 gap

[0145] 52 direction of rotation

[0146] ID inner diameter

[0147] OD outer diameter

[0148] X axis of rotation BH bar height BW bar width

[0149] D distance / pitch

Claims

1. Claims1. Refiner plate (18) for a refiner (10) having one or more rotors (16) that is rotatable about an axis of rotation and cooperate with one of more stators (14) to mechanically treat a pulp containing cellulosic fibres, the refiner plates (18) being mountable to a rotor (16) or stator (14), the refiner plate (18) including: a base (22); and a plurality of spaced-apart refiner bars (30), wherein at least some of the bars (30) are tilted with respect to the base (22) such that the leading surface (39) of the exposed bars is essentially oriented in an acute angle (31) of less than 90° with respect to the base (22), characterized in that the acute angle (31) is in the range of 60° to 70°.

2. The refiner plate (18) for a refiner (10) having one or more rotors (16) that is rotatable about an axis of rotation and cooperate with one of more stators (14) to mechanically treat a pulp containing cellulosic fibres, the refiner plates (18) being mountable to a rotor (16) or stator (14), the refiner plate (18) including: a base (22); and a plurality of spaced-apart refiner bars (30) wherein characterized in that at least some of the bars (30) are tilted with respect to the base (22) such that the leading surface (39) of the exposed bars is essentially oriented in an acute angle (31) of less than 90° with respect to the base (22), characterized in that there are spacers (24) between the bars (30), and at least some of the spacers (24) are tilted with respect to the base (22) such that the spacers (24) and base (22) are essentially oriented in an acute angle (31) of less than 90° with respect to the base (22), preferably with an acute angle (21) of 50° to 80°, and most preferably with an acute angle (21) in the range of 60° to 70°.

3. The refiner plate (18) of claim 2 wherein wherein the bars (30) and spacers (24) extend essentially parallel with respect to each other.

4. The refiner plate (18) of any one of claims 1 to 3 wherein the bars (30) and / or spacers (24) are integrally formed within the base (22).

5. The refiner plate (18) of any one of claims 1 to 4, wherein downward sections of the bars (30) are embedded in a solidified material, wherein preferably he material is a layer (43) and / or is formed of epoxy or metal.

6. The refiner plate (18) of any one of claims 1 to 5 wherein the bars (30) and / or spacers (24) are attached to the base (22) by means of brazing, welding, pressfitting or gluing.

7. The refiner plate (18) of any one of claims 1 to 3 wherein more than 10% of the bars (30) have an angle of 90° with respect to the base (22).

8. The refiner plate (18) for a refiner (10) having one or more rotors (16) that is rotatable about an axis of rotation and cooperate with one of more stators (14) to mechanically treat a pulp containing cellulosic fibres, the refiner plate (18) being mountable to a rotor (16) or stator (14), the refiner plate (18) including: a base (22); and a plurality of spaced-apart refiner bars (30), wherein at least some of the bars (30) are tilted with respect to the base (22) such that the leading surface (39) of the tilted bars is essentially oriented in an acute angle (31) of less than 90° with respect to the base (22), characterized in that not all tilted bars (30) are tilted at the same angle.

9. The refiner plate (18) of claim 8, characterized by the characterizing features of any one of claims 1 to 7.

10. The refiner plate (18) of claim 8 or 9, characterized in that the tilt angle of the refiner bars (30) is increasing within a section of the refiner plate (18).11 . The refiner plate (18) of claim 8 or 9, characterized in that the refiner plate has different sections, and the tilt angle of the refiner bars (30) is different in the different sections.

12. The refiner plate (18) of claim 11 , characterized in that the tilt angle of the refiner bars (30) in at least one of the different sections is essentially the same.

13. The refiner plate (18) of any one of claim 11 to 13 characterized in that the tilt angle of the refiner bars (30) decreases radially outwardly with respect to an axis of rotation of a rotor comprising the refiner plate.

14. The refiner plate (18) of claim 8 or 9, characterized in that at least one bar is oriented at a rectangular angle and at least some of the bars (30) are tilted with respect to the base (22) such that the leading surface (39) of the exposed bars is essentially oriented in an acute angle (31) of less than 90° with respect to the base (22), (see Fig. 17).

15. The refiner plate (18) of claim 8 or 9, characterized in that a plurality of bars is oriented at a rectangular angle in one section and a plurality of bars (30) is tilted with respect to the base (22) within an adjacent section of the refiner plate, (see Fig. 19).

16. The refiner plate (18) of any one of claims 1 to 15 wherein the bars (30) and / or spacers (24) have a trapezoidal shape in cross-section.

17. The refiner plate (18) of claim 16 wherein at least some of the bars (30) have a leading edge (32) being defined by an acute angle (31) between the surrounding leading and outer bar surfaces, preferably wherein the most outward surface (36) of the bar (30) is oriented essentially parallel to the base (22).

18. The refiner plate (18) of claim 17 further comprising a trailing edge (32) defined by an obtuse angle (33) between the surrounding trailing and outer bar surfaces.

19. The refiner plate (18) of any one of claims 2-18, characterized in that spacers have an inclined upper surface and an inclined lower surface.

20. The refiner plate (18) of any one of claims 2-18, characterized in that spacers have a horizontal upper surface and an inclined lower surface.

21. The refiner plate (18) of any one of claims 2-18, characterized in that spacers have an inclined upper surface and a horizontal lower surface.

22. The refiner plate (18) of any one of claims 2-18, characterized in that spacers have an inclined upper surface and a horizontal lower surface.

23. The refiner plate (18) of any one claims 1 to 22 wherein the bars (30) are positioned and press-fitted and / or glued within slots (40) formed within a slotted support plate (42) attached to a base (22), wherein the spacing of the slots (40) defines the spacing of the bars (30).

24. The refiner plate (18) of claim 23, wherein the bars protrude upwardly and downwardly from the slotted support plate (42).

25. The refiner plate (18) of any one of claims 1 to 24, wherein the base (22), bars (30) and spacers (24) are made of metal, wherein preferably the base (22), bars (30) and spacers (24) are made of dissimilar metals.

26. The refiner plate (18) of any one of claims 1 to 25 wherein bars (30) have been bent for part of their length extending beyond the spacers (24).

27. The refiner plate (18) of any one of claims 1 to 25 wherein at least some of the refiner bars (30) have a surface coated with a coating, preferably a coating having a variable-coating thickness that varies along the bar height (BH).

28. A refiner (10) comprising: a housing (12); one or more stators (14) supported within the housing (12); one or more rotors (16) that are rotatable about an axis of rotation and cooperating with the stators (14) to mechanically treat a pulp containing fibers; characterized by at least one refiner plate (18) as defined in any one of claims 1 to 27 fastened to the rotors (16) and stators (14).

29. A refiner (10) of claim 28, characterized in that the rotor (16) or stator (14) having preferably a majority of bars (30), which are oriented in a right angle with respect to the base, and the stator (14) or rotor (16) having tilted bars (30).

30. Refiner of any of one of claims 1 to 29, characterized by a stator having a plurality of refiner bars, which are oriented in a right angle with respect to the base, and a rotor or stator having a plurality of tilted refiner bars.

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