Equipment and method for processing wood fibers

Abstract

A grinding member includes a grinding body having a grinding surface, the grinding surface including first and second grinding machine bars separated by first and second grinding machine grooves, respectively. The first grinding machine bar extends from a radially inner position to a first radially outer position. The second grinding machine bar extends to a second radially outer position that is closer to the outermost part of the grinding body than the first radially outer position. The second grinding machine bar has a longitudinal length of about 0.6 cm to about 10 cm. The first and second grinding machine bars have first and second maximum heights extending upward from the bottoms of their respective adjacent first or second grinding machine grooves, respectively. The second maximum height is at least 0.35 mm less than the first maximum height. The first grinding machine bar is adapted to grind wood fibers, and the second grinding machine bar is adapted to break fiber bundles.

Description

[0001] This patent application is a divisional application of the patent application with application number 201980009186.8 (international application number PCT / US2019 / 012054), applicant "International Paper Company", and invention title "Equipment and Method for Processing Wood Fibers".

[0002] Related Applications

[0003] This application relates to the following applications filed simultaneously therewith: U.S. Patent Application No. 15 / 860,006 (Attorney Docket No. TEC-120257-US) filed by Dwight Anderson, titled "Equipment and Method for Processing Wood Fibers", the entire content of which is incorporated herein by reference. Technical Field

[0004] The present disclosure generally relates to processing wood fibers in a refiner, and more particularly, to equipment and methods for refining wood fibers and breaking fiber bundles. Background Art

[0005] Traditionally, disk refiners have been used to process wood fibers in one step of the paper product manufacturing process. Such a refiner includes a first refining member and a second refining member with a refining space therebetween. Each of the first and second refining members includes a plurality of refiner bars separated by refiner grooves, wherein the refiner bars define cutting surfaces for cutting the wood fibers. During operation, at least one of the first and second refining members rotates relative to the other, and at this time, the rotation of the cutting surfaces of the refiner bars cuts the wood fibers being processed in the refiner. Once the wood fibers have been processed in the refiner, the processed wood fibers can be further processed in subsequent paper product manufacturing processes to produce paper products. In some cases, the wood fibers can be further processed in, for example, a separate tickler refiner or a high-frequency defibrator. Summary of the Invention

[0006] According to a first aspect of the present invention, there is provided a grinding member for a wood pulp grinder. The grinding member includes a grinding body, the grinding body includes a grinding surface, the grinding surface includes first grinding machine bars separated by first grinding machine grooves and second grinding machine bars separated by second grinding machine grooves. Each first grinding machine bar extends from a radially inner position on the grinding surface to a first radially outer position on the grinding surface. Each second grinding machine bar extends to a second radially outer position on the grinding surface. The second grinding machine bar has a longitudinal length from about 0.6 cm to about 10 cm, wherein the second radially outer position is closer to the outermost part of the grinding body than the first radially outer position. The first grinding machine bar has a first maximum height extending upward from the bottom of the adjacent first grinding machine groove, and the second grinding machine bar has a second maximum height extending upward from the bottom of the adjacent second grinding machine groove. The second maximum height is at least 0.35 mm smaller than the first maximum height. The first grinding machine bar is adapted to grind wood fibers, and the second grinding machine bar is adapted to break fiber bundles.

[0007] The first maximum height of the first grinding machine bar, when measured from the bottom of the adjacent first grinding machine groove, can be from about 4 mm to about 10 mm. The second maximum height of the second grinding machine bar, when measured from the bottom of the adjacent second grinding machine groove, can be about 0.35 mm to about 1.5 mm smaller than the first maximum height. The second maximum height of the second grinding machine bar, when measured from the bottom of the adjacent second grinding machine groove, can be about 0.7 mm to about 1.5 mm smaller than the first maximum height.

[0008] The longitudinal length of the second grinding machine bar can be from about 2 cm to about 10 cm.

[0009] The second grinding machine bar and the first grinding machine bar can be integral, such that the second grinding machine bar extends from the first radially outer position to the second radially outer position. Each second grinding machine bar can continuously slope downward from the first radially outer position to the second radially outer position.

[0010] The first and second grinding machine bars can have a width extending between the side edges of about 2 mm to about 8 mm.

[0011] At least a part of the first grinding machine groove can be provided with a dam.

[0012] The grinding member may further include a third grinding bar separated by a third grinding groove and a fourth grinding bar separated by a fourth grinding groove. Each third grinding bar may extend to a third radially outer position on the grinding surface, and each fourth grinding bar may extend to a fourth radially outer position on the grinding surface. The fourth grinding bar may have a longitudinal length of about 0.6 cm to about 10 cm. The fourth radially outer position may be closer to the outermost part of the grinding body than the third radially outer position. The third grinding bar may have a third maximum height extending upward from the bottom of the adjacent third grinding groove, and the fourth grinding bar may have a fourth maximum height extending upward from the bottom of the adjacent fourth grinding groove. The fourth maximum height may be at least 0.35 mm less than the third maximum height. The third grinding bar may be adapted to grind wood fibers, and the fourth grinding bar may be adapted to break fiber bundles.

[0013] The third grinding bar and the second grinding bar may be integral such that the third grinding bar extends from the second radially outer position to the third radially outer position, and the fourth grinding bar and the third grinding bar may be integral such that the fourth grinding bar extends from the third radially outer position to the fourth radially outer position.

[0014] According to a second aspect of the present disclosure, a wood pulp grinder is provided. The wood pulp grinder includes: a frame, at least a first pair of grinding members, and a rotor associated with the frame. The grinding members include a first grinding member associated with the frame and including a first grinding body, and a second grinding member associated with the frame and including a second grinding body. The first grinding body includes a first grinding surface, and the first grinding surface includes: first grinding machine bars separated by first grinding machine grooves, each first grinding machine bar extending from a radially inner position on the grinding surface to a first radially outer position on the grinding surface; and second grinding machine bars separated by second grinding machine grooves, each second grinding machine bar extending to a second radially outer position on the grinding surface. The longitudinal length of the second grinding machine bars is about 0.6 cm to about 10 cm. The second radially outer position may be closer to the outermost part of the grinding body than the first radially outer position. The first grinding machine bars have a first maximum height extending upward from the bottom of adjacent first grooves, and the second grinding machine bars have a second maximum height extending upward from the bottom of adjacent second grooves. The second maximum height is at least 0.35 mm smaller than the first maximum height. The second grinding member includes a second grinding surface, and the second grinding surface includes second member grinding machine bars separated by second member grinding machine grooves. The first grinding member is spaced apart from the second grinding member to define a grinding space therebetween. The rotor is coupled to one of the first grinding member or the second grinding member such that rotation of the rotor causes one of the first grinding member or the second grinding member to move relative to the other. When a wood pulp slurry containing wood fibers is supplied to the frame, the wood pulp slurry passes through the grinding space such that a large number of wood fibers in the wood pulp slurry are ground and a plurality of wood fiber bundles in the wood pulp slurry are separated.

[0015] The second maximum height may be at least 0.7 mm smaller than the first maximum height.

[0016] The longitudinal length of the second grinding machine bars may be about 2 cm to about 10 cm.

[0017] The second member grinding machine bars may include: third grinding machine bars extending from a radially inner position on the second grinding surface to a first radially outer position on the second grinding surface; and fourth grinding machine bars extending to a second radially outer position on the second grinding surface. The second radially outer position may be closer to the outermost part of the second grinding body than the first radially outer position. The third grinding machine bars may have a third maximum height extending upward from the bottom of adjacent grooves, and the fourth grinding machine bars may have a fourth maximum height extending upward from the bottom of adjacent grooves. The fourth maximum height may be at least 0.35 mm smaller than the third maximum height.

[0018] The first grinding member may be a non-rotating stator member, and the second grinding member may be a rotating rotor member.

[0019] According to a third aspect of the present disclosure, a method for processing wood fibers is provided. The method includes: providing a grinder including at least a first pair of grinding members. The grinding members include: a first grinding member including a first grinding body and a second grinding member including a second grinding body. The first grinding body includes a first grinding surface, and the first grinding surface includes: a first grinding bar, which is separated by a first grinding groove and has a first maximum height extending upward from the bottom of the adjacent first grinding groove; and a second grinding bar, which is separated by a second grinding groove and has a second maximum height extending upward from the bottom of the adjacent second grinding groove. The second grinding body includes a second grinding surface, and the second grinding surface includes second member grinding bars separated by second member grinding grooves. The first grinding member is spaced apart from the second grinding member to define a grinding space therebetween. At least a portion of the second member grinding bars is positioned opposite the second grinding bars, thereby defining a gap between this portion of the second member grinding bars and the second grinding bars. The method further includes: rotating at least one of the first grinding member or the second grinding member such that the first grinding member and the second grinding member move relative to each other; supplying a wood pulp slurry containing wood fibers to the grinder such that the slurry passes through the grinding space; and applying an axial pressure to at least one of the first grinding member or the second grinding member when supplying the slurry such that the gap between this portion of the second member grinding bars and the second grinding bars is between about 0.9 mm and about 1.5 mm, and in this gap, at least a portion of the wood fiber bundles passing through the gap are separated.

[0020] The second grinding bar may have a longitudinal length of about 0.6 cm to about 10 cm, and the second maximum height may be at least 0.35 mm less than the first maximum height. The longitudinal length of the second grinding bar may be about 2 cm to about 10 cm.

[0021] The second member grinding bars may include: a third grinding bar and a fourth grinding bar. The third grinding bar may have a third maximum height extending upward from the bottom of the adjacent groove, and the fourth grinding bar may have a fourth maximum height extending upward from the bottom of the adjacent groove. The fourth maximum height may be at least 0.35 mm less than the third maximum height.

[0022] According to a fourth aspect of the present disclosure, a grinding member for a wood pulp grinder is provided. The grinding member includes: a grinding body including a plurality of radially extending disc-shaped sections, the disc-shaped sections including: at least one first disc-shaped section and at least one second disc-shaped section. The at least one first disc-shaped section includes a first grinding surface, the first grinding surface including first grinding machine bars separated by first grinding machine grooves. The first grinding machine bars have a first maximum height extending upward from the bottom of adjacent first grinding machine grooves. The at least one second disc-shaped section includes a second grinding surface, the second grinding surface including second grinding machine bars separated by second grinding machine grooves. The second grinding machine bars have a second maximum height extending upward from the bottom of adjacent second grinding machine grooves. The second maximum height is at least 0.35 mm less than the first maximum height. The first grinding machine bars are adapted to grind wood fibers, and the second grinding machine bars are adapted to break fiber bundles.

[0023] The first maximum height of the first grinding machine bars, when measured from the bottom of adjacent first grinding machine grooves, can be from about 4 mm to about 10 mm.

[0024] The second maximum height of the second grinding machine bars, when measured from the bottom of adjacent second grinding machine grooves, can be about 0.35 mm to about 1.5 mm less than the first maximum height.

[0025] The second maximum height of the second grinding machine bars, when measured from the bottom of adjacent second grinding machine grooves, can be about 0.7 mm to about 1.5 mm less than the first maximum height.

[0026] According to a fifth aspect of the present disclosure, a wood pulp grinder is provided. The wood pulp grinder includes: a frame, at least a first pair of grinding members, and a rotor associated with the frame. The grinding members include: a first grinding member associated with the frame and including a first grinding body; and a second grinding member associated with the frame and including a second grinding body. The first grinding body includes a plurality of radially extending disc-shaped segments, the disc-shaped segments including: at least one first disc-shaped segment and at least one second disc-shaped segment. The at least one first disc-shaped segment includes a first grinding surface, the first grinding surface including first grinding machine bars separated by first grinding machine grooves. The first grinding machine bars have a first maximum height extending upward from the bottom of adjacent first grinding machine grooves. The at least one second disc-shaped segment includes a second grinding surface, the second grinding surface including second grinding machine bars separated by second grinding machine grooves. The second grinding machine bars have a second maximum height extending upward from the bottom of adjacent second grinding machine grooves. The second maximum height is at least 0.35 millimeters less than the first maximum height. The second grinding body includes a second member grinding surface, the second member grinding surface including second member grinding machine bars separated by second member grinding machine grooves. The first grinding member is spaced apart from the second grinding member to define a grinding space therebetween. The rotor is coupled to one of the first grinding member or the second grinding member such that rotation of the rotor causes relative movement of the first grinding member and the second grinding member with respect to each other. When a wood pulp slurry containing wood fibers is supplied to the frame, the wood pulp slurry passes through the grinding space, causing a large number of wood fibers in the wood pulp slurry to be ground and separating a plurality of wood fiber bundles in the wood pulp slurry.

[0027] The second maximum height of the second grinding machine bars, when measured from the bottom of adjacent second grinding machine grooves, may be about 0.35 mm to about 1.5 mm less than the first maximum height.

[0028] The second maximum height of the second grinding machine bars, when measured from the bottom of adjacent second grinding machine grooves, may be about 0.7 mm to about 1.5 mm less than the first maximum height.

[0029] The second grinding member may include a plurality of radially extending disc-shaped segments, the disc-shaped segments including: at least one third disc-shaped segment and at least one fourth disc-shaped segment. The at least one third disc-shaped segment may include a third grinding surface including third grinding bars separated by third grinding grooves. The third grinding bars may have a third maximum height extending upward from the bottom of adjacent third grinding grooves. The at least one fourth disc-shaped segment may include a fourth grinding surface including fourth grinding bars separated by fourth grinding grooves. The fourth grinding bars may have a fourth maximum height extending upward from the bottom of adjacent fourth grinding grooves. The fourth maximum height may be at least 0.35 mm less than the third maximum height. The third and fourth grinding bars may define second member grinding bars, and the third and fourth grinding grooves may define second member grinding grooves.

[0030] The first grinding member may be a non-rotating stator member, and the second grinding member may be a rotating rotor member.

[0031] According to a sixth aspect of the present disclosure, there is provided a grinding member for a wood pulp grinder. The grinding member includes a grinding body including a grinding surface including: grinding bars separated by grinding grooves, each grinding bar extending from a radially inner position on the grinding surface to a first radially outer position on the grinding surface; and teeth extending to a second radially outer position on the grinding surface. The second radially outer position is closer to the outermost part of the grinding body than the first radially outer position. The grinding bars are adapted to grind wood fibers, and the teeth are adapted to break fiber bundles.

[0032] When measured from the bottom of adjacent grinding grooves, the grinding bars may have a first maximum height from about 4 mm to about 10 mm.

[0033] The width of the grinding bars extending between the side edges may be from about 2 mm to about 8 mm.

[0034] At least a portion of the grinding grooves may be provided with dams.

[0035] According to a seventh aspect of the present disclosure, a wood pulp grinder is provided. The wood pulp grinder includes a frame, at least a first pair of grinding members, and a rotor associated with the frame. The grinding members include a first grinding member associated with the frame and including a first grinding body having a first grinding surface; and a second grinding member associated with the frame and including a second grinding body having a second grinding surface. The first grinding surface includes: first grinding machine bars separated by first grinding machine grooves, each first grinding machine bar extending from a radially inner position on the first grinding surface to a first radially outer position on the first grinding surface; and first teeth extending to a further radially outer position on the first grinding surface. The further radially outer position is closer to the outermost part of the first grinding body than the first radially outer position. The first grinding member is spaced apart from the second grinding member so as to define a grinding space therebetween. The rotor is coupled to one of the first grinding member or the second grinding member such that rotation of the rotor causes relative movement of the first grinding member and the second grinding member with respect to each other. When a wood pulp slurry containing wood fibers is supplied to the frame, the wood pulp slurry passes through the grinding space such that a large number of wood fibers in the wood pulp slurry are ground and a plurality of wood fiber bundles in the wood pulp slurry are separated.

[0036] The second grinding member may include a second grinding body including a second grinding surface, the second grinding surface including: second grinding machine bars separated by second grinding machine grooves, each second grinding machine bar extending from a radially inner position on the second grinding surface to a first radially outer position on the second grinding surface; and second teeth extending to a second radially outer position on the second grinding surface. The second radially outer position may be closer to the outermost part of the second grinding body than the first radially outer position.

[0037] The second grinding surface may include a first row of second teeth extending to a second radially outer position on the second grinding surface and a second row of second teeth extending to a fourth radially outer position on the second grinding surface. The first teeth and the second teeth mesh with each other.

[0038] The first grinding member may be a non-rotating stator member and the second grinding member may be a rotating rotor member. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Although the claims at the end of the specification particularly point out and distinctly claim the invention, it is believed that the invention will be better understood from the following description in conjunction with the drawings, in which like reference numerals represent like elements and in which:

[0040] Figure 1 is a schematic partial cross-sectional view of a disk grinder;

[0041] Figure 2 andFigure 3 Top views of a first grinding body and a second grinding body respectively;

[0042] Figure 4A and Figure 4B is Figure 2 A top view of a section of the grinding surface of the first grinding body in;

[0043] Figure 5A and Figure 5B is Figure 3 A top view of a section of the grinding surface of the second grinding body in;

[0044] Figure 6A is along Figure 4A and Figure 5A A partial sectional view of the grinding body taken along line 6A-6A in;

[0045] Figure 6B is along Figure 4B and Figure 5B A partial sectional view of the grinding body taken along line 6B-6B in;

[0046] Figure 7 is along 4A, Figure 4B , Figure 5A and Figure 5B A partial sectional view taken along line 7-7 in;

[0047] Figure 8 and Figure 9 A partial sectional view of the grinding bars on the first grinding body, the grinding bars being spaced apart from and located above the corresponding grinding bars on the second grinding body;

[0048] Figure 10 and Figure 11 Top views of a part of the first grinding body and the second grinding body respectively, including a plurality of radially extending pie-shaped sections;

[0049] Figure 12A and Figure 12B is from Figure 10 and Figure 11 A partial sectional view of the grinding bars of the pie-shaped sections in, wherein one grinding body is spaced apart from and located above the other grinding body;

[0050] Figure 13 and Figure 14 Top views of the first grinding body and the second grinding body respectively, including teeth;

[0051] Figure 15 is Figure 13 A top view of a section of the grinding surface of the first grinding body in;

[0052] Figure 16 is Figure 14Top view of a section of the grinding surface of the second grinding body;

[0053] Figure 17 is a partial cross-sectional view of the grinding bars and teeth on the first grinding body, the first grinding body being spaced apart from and located above the second grinding body including the grinding bars and teeth; and

[0054] Figure 18 is a flowchart showing an exemplary method for processing wood fibers. Detailed Description

[0055] In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration and not limitation specific preferred embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and changes may be made without departing from the spirit and scope of the invention.

[0056] Figure 1 Shows a schematic partial cross-sectional view of a disk grinder 10 according to the present disclosure. The disk grinder 10 includes a housing having a first housing member 12 and a second housing member 14, which may be bolted together or otherwise fixedly attached. The housing members 12, 14 define an inlet 16, an outlet 18, and a grinder inner cavity 64 containing one or more pairs of grinding members. Figure 1 The embodiment shown in is a double-disk grinder 10, which includes two pairs of grinding members, for example, a first grinding member 20 paired with a second grinding member 30 and a third grinding member 40 paired with a fourth grinding member 50. The first grinding member 20 includes a first grinding body 22 having a first grinding surface 24, and the second grinding member 30 includes a second grinding body 32 having a second grinding surface 34. The third grinding member 40 includes a third grinding body 42 and a third grinding surface 44, and the fourth grinding member 50 includes a fourth grinding body 52 and a fourth grinding surface 54. According to the present disclosure, each of the grinding members 20, 30, 40, 50 is associated with a main support frame, which includes a fixed support frame 66 fixed to the first housing member 12 and a movable support frame 68.

[0057] The first, second, third, and fourth grinding bodies 22, 32, 42, 52 may be generally disk-shaped and have substantially the same outer diameter (see Figure 2 and 3)。The first and second grinding members 20, 30 are arranged such that the first grinding surface 24 faces the second grinding surface 34, and the third and fourth grinding members 40, 50 are arranged such that the third grinding surface 44 faces the fourth grinding surface 54. The first grinding member 20 is spaced apart from the second grinding member 30 so as to define a first grinding space 60 between their respective grinding surfaces 24, 34. The third grinding member 40 is spaced apart from the fourth grinding member 50 so as to define a second grinding space 62 between their respective grinding surfaces 44, 54. The structure of the disk grinder 10 may be similar to the structure shown in U.S. Patent Application Publication No. 2006 / 0037728A1, the disclosure of which is incorporated herein by reference.

[0058] In Figure 1 the illustrated embodiment, the first and fourth grinding members 20, 50 are stationary, and the second and third grinding members 30, 40 rotate relative to the first and fourth grinding members 20, 50. The first grinding member 20 may be fixed to the support frame 66 by bolts or other suitable fasteners (not shown). The second and third grinding members 30, 40 may be attached to a support 70 that is coupled to a rotating shaft 72 and extends radially outward from the rotating shaft 72. The support 70 is coupled to the shaft 72 so as to rotate with the shaft 72 and is also axially movable along the shaft 72. The shaft 72 is driven by a first motor 74 such that the support 70 and the second and third grinding members 30, 40 rotate with the shaft 72 during operation of the disk grinder 10. The shaft 72 has a central axis 72A that is generally coaxial with the rotational axes of the second and third grinding members 30, 40. The shaft 72 may be rotatably mounted to a fixed support frame 66 such that the first and second grinding members 30, 40 are associated with the main support frame. As described in the present disclosure, the support 70 may be axially movable along the shaft 72, for example, axially relative to the first and fourth grinding members 20, 50 substantially along the central axis 72A. The fourth grinding member 50 may be fixed to a movable support frame 68 by bolts or other suitable fasteners (not shown). Thus, the support 70 and the shaft 72 may define a rotor associated with the main support frame such that the second and third grinding members may define rotating rotor members, while the first and fourth grinding members 20, 50 may define non-rotating stator members. Rotation of the rotor causes movement of the second and third grinding members 30, 40 relative to the first and fourth grinding members 20, 50, respectively.

[0059] The movable support frame 68 can be installed in the second housing member 14 and coupled to a second motor 76, which can include a position-fixed reversible electric motor. The second motor 76 moves the movable support frame 68 in a generally horizontal (i.e., axial) direction as shown by arrow A. The grinder 10 can include, for example, a screw jack (not shown) coupled to the second motor 76 and the movable support frame 68, and the second motor 76 can rotate the screw jack to move the movable support frame 68 to which, for example, a fourth grinding member 50 is attached. This movement adjusts the size of the gaps defined between the first and second grinding members 20, 30 and between the third and fourth grinding members 40, 50, i.e., the size of the first and second grinding spaces 60, 62 (see also Figure 8 and Figure 9 ). In other embodiments (not shown), control of the gap size can be achieved by one or more magnetic bearings. The magnetic bearings control the axial position of the shaft 72, which can be used to control the position of a rotating rotor member fixed to the shaft 72. The magnetic bearings can be used to control the axial position of one or more other movable sections (i.e., the movable support frame 68) of the main support frame to which one or more non-rotating stator members are attached.

[0060] As further discussed in this disclosure, a wood pulp slurry containing wood fibers passes through the grinding spaces 60, 62. When the screw jack rotates in a first direction, it causes the movable support frame 68 and the fourth grinding member 50 to move inwardly towards the third grinding member 40. The fourth grinding member 50 then applies an axial force to the wood pulp slurry passing through the second grinding space 62, and the wood pulp slurry in turn applies an axial force to the third grinding member 40, causing the third grinding member 40, the support 70, and the second grinding member 30 to move inwardly towards the first grinding member 20. When the screw jack rotates in a second direction opposite to the first direction, it causes the movable support frame 68 and the fourth grinding member 50 to move outwardly away from the third grinding member 40. This reduces the axial force applied by the fourth grinding member 50 to the wood pulp slurry passing through the second grinding space 62, and in turn reduces the axial force applied by the wood pulp slurry to the third grinding member 40. The axial force applied by the wood pulp slurry passing through the first grinding space 60 is then sufficient to cause the second grinding member 30, the support 70, and the third grinding member 40 to move towards the fourth grinding member 50. This situation continues until the axial forces applied by the wood pulp passing through the first and second grinding spaces 60, 62 to the second and third grinding members 30 and 40 are approximately equal.

[0061] In some embodiments (not shown), the disk grinder 10 may further include another motor and a second rotating shaft, and the first and / or fourth grinding members 20, 50 may be coupled to the second rotating shaft such that the first and / or fourth grinding members 20, 50 may rotate in opposite directions relative to the second and / or third grinding members 30, 40, respectively. In other embodiments (not shown), the disk grinder 10 may include only a pair of grinding members, where one grinding member is a non-rotating stator member and the other grinding member is a rotating rotor member. In further embodiments (not shown), the disk grinder may include three or more pairs of grinding members. In additional embodiments (not shown), the disk grinder 10 may include a conical grinder having one or more pairs of grinding members.

[0062] Figure 2 And Figure 3 are top views of the grinding surfaces 24, 34 of the first grinding body 22 and the second grinding body 32, respectively, for a pulp grinder according to an embodiment of the present disclosure. Although not discussed in detail here, the structures of the grinding surfaces 44, 54 of the third and fourth grinding bodies 42, 52 (see Figure 1 ) may be generally similar to the grinding surfaces 24, 34 of the first and second grinding bodies 22, 32, respectively.

[0063] See Figure 1 and Figure 2 , the first grinding body 22 may include a plurality of components, such as components 22A - 22C, which are bolted or otherwise attached together to form a disk-shaped grinding body 22 including a radially outer edge 27. The grinding surface 24 includes a plurality of elongated grinding bars 26 separated from each other by grinding machine grooves 28. Although not shown in Figure 2 , it can be understood that other components (not labeled) of the first grinding body 22 will similarly include grinding bars 26 and grinding machine grooves 28. The grinding bars 26 extend radially outward from a radially inner portion 23 of the first grinding body 22 toward the radially outer edge 27. The grinding bars 26 may be inclined at various angles as shown in Figure 2 , and each component 22A - 22C may include one or more sections (not separately labeled) of grinding bars 26 inclined in different directions. Figure 2 The grinding bars 26 and the grinding machine grooves 28 within each component 22A - 22C in

[0064] may be structurally similar in other respects. Figure 3As shown, the second grinding body 32 can similarly include a plurality of components, such as components 32A - 32C, which are bolted or otherwise attached together to form a disc-shaped grinding body 32 including a radial outer edge 37. The grinding surface 34 includes a plurality of elongated grinding bars 36, which are separated from each other by grinding grooves 38. Although not shown in Figure 3 , it can be understood that other components (not labeled) of the second grinding body 32 can similarly include grinding bars 36 and grinding grooves 38. The grinding bars 36 extend radially outward from a radially inner portion 33 of the second grinding body 32 toward the radial outer edge 37. The grinding bars 36 can be inclined at various angles as Figure 3 shown, and each component 32A - 32C can include two or more sections (not separately labeled) of grinding bars 36 inclined in different directions. Figure 3 The grinding bars 36 and grinding grooves 38 within each component 32A - 32C in

[0065] can be structurally similar in other respects. Figure 1 The path of the pulp of the wood pulp containing wood fibers through the grinder 10 is indicated by arrow B in Figures 1 to 3, the wood pulp slurry enters the disk refiner 10 through the inlet 16 and enters the refiner inner cavity 64 through the central hole 21 in the first grinding member 20. The refiner inner cavity 64 can be partially defined by a fixed support frame 66 and a movable support frame 68. The grinding surfaces 24, 34 can include one or more rows of additional refiner bars (not labeled), such as refiner bars near the center of the grinding bodies 22, 32 (e.g., near the central hole 21). These additional refiner bars can be wider and more spaced apart than the other refiner bars 26 to break large fiber bundles before they enter the grinding space 60. The wood fibers travel radially outward between the grinding members 20, 30, 40, 50. The first grinding space 60 defined between the first and second grinding members 20, 30 and the second grinding space 62 defined between the third and fourth grinding members 40, 50 define separate paths along which the wood fibers can travel from the inlet 16 to the outlet 18. It can be considered that the wood fibers pass through only one of the first and second grinding spaces 60, 62 at a time. The refiner grooves 28, 38 can be considered as part of the grinding space 60 defined between the first and second grinding members 20, 30. It can be considered that most of the wood fiber flow passing through the grinding space 60 passes through the refiner grooves 28, 38. Similarly, the refiner grooves (not shown) of the third and fourth grinding members 40, 50 can be considered as part of the grinding space 62 defined between the third and fourth grinding members 40, 50. It can be considered that most of the wood fiber flow passing through the grinding space 62 passes through the refiner grooves (not labeled) of the third and fourth grinding members 40, 50. After processing, the wood fibers leave the refiner 10 via the outlet 18 at least partially under the action of centrifugal force.

[0066] Figure 4A and Figure 4B is a detailed view of a part of the grinding surface 24 of the first grinding body 22. Figure 5A and Figure 5B is a detailed view of the corresponding part of the grinding surface 34 of the second grinding body 32. Figure 6A and 6B are partial cross-sectional views of the grinding bodies 22, 32 taken along lines 6A - 6A and 6B - 6B respectively, showing Figure 4A , 4B , two embodiments of the refiner bars 26, 36 shown in 5A and 5B. Figure 7 is along Figure 4A , 4B , 5A and 5B taken along line 7 - 7 of the partial cross-sectional view.

[0067] At Figure 4A , 5A, in the embodiments shown in FIGS. 6A and 7, each grinding bar 26, 36 may include a first grinding bar 26A, 36A and a second grinding bar 26B, 36B. The first grinding bars 26A, 36A may be separated from each other by first grinding grooves 28A, 38A, and the second grinding bars 26B, 36B may be separated from each other by second grinding grooves 28B, 38B. The first and second grinding grooves 28A, 38A, 28B, 38B may have a width W of about 2 mm to about 6 mm G . As Figure 6A and 7 shown, the first grinding bars 26A, 36A include a first maximum height H1 extending upward from the bottom F1 of the adjacent first grinding grooves 28A, 38A, and the second grinding bars 26B, 36B include a second maximum height H2 extending upward from the bottom F2 of the adjacent second grinding grooves 28B, 38B, wherein the second maximum height H2 is less than the first maximum height H1. The minimum height difference between H1 and H2 is drawn as D1 in Figure 6A . In some examples, the radially outer portion RO1 of the first grinding bars 26A, 36A may include a step from the first maximum height H1 to the second maximum height H2.

[0068] In some examples, the second maximum height H2 may be at least 0.35 mm less than the first maximum height H1. In other examples, the second maximum height H2 may be at least 0.70 mm less than the first maximum height H1. In further examples, when measured from the bottom F1 of the adjacent first grinding grooves 28A, 38A, the first maximum height H1 of the first grinding bars 26A, 36A may be about 4 mm to about 10 mm. In a specific example, when measured from the bottom F2 of the adjacent second grinding grooves 28B, 38B, the second maximum height H2 of the second grinding bars 26B, 36B may be about 0.35 mm to about 1.5 mm less than the first maximum height H1. In another specific example, when measured from the bottom F2 of the adjacent second grinding grooves 28B, 38B, the second maximum height H2 of the second grinding bars 26B, 36B may be about 0.7 mm to about 1.5 mm less than the first maximum height H1. In other examples, the first grinding bars 26A, 36A and the second grinding bars 26B, 36B may include a width W extending between the side edges of the respective grinding bars 26A, 36A, 26B, 36B 26 , which is about 2 mm to about 8 mm.

[0069] Each of the first grinding bars 26A, 36A extends from a radially inner position P1 on the grinding surfaces 24, 34 to a first radially outer position P2 on the grinding surfaces 24, 34. Each of the second grinding bars 26B, 36B extends to a second radially outer position P3 on the grinding surfaces 24, 34. The second radially outer position P3 can be closer to the outermost part of the grinding bodies 22, 32, e.g., the radial outer edges 27, 37, than the first radially outer position P2. In some examples, the radially inner position P1 can include a position at or near the radially inner portions 23, 33. The second grinding bars 26B, 36B can include a longitudinal length L1 of about 0.6 cm to about 10 cm, preferably about 2 cm to about 10 cm.

[0070] In some embodiments, as Figure 4A , 5A and as shown in 6A, the second grinding bars 26B, 36B and the first grinding bars 26A, 36A can be integral, with the second grinding bars 26B, 36B extending from the first radially outer position P2 to the second radially outer position P3. In one specific embodiment, the second grinding bars 26B, 36B can slope continuously downward from the first radially outer position P2 to the second radially outer position P3. As Figure 6A shown, the height of the second grinding bars 26B, 36B can continuously decrease from a second maximum height H2 to a second minimum height H 2' along substantially the entire longitudinal length L1. In another specific embodiment, as Figure 6A depicted by the dashed line in, the second grinding bars 26B, 36B can extend substantially horizontally from the first radially outer position P2 to the second radially outer position P3, such that the second grinding bars 26B, 36B are at the second maximum height H2 along substantially the entire longitudinal length L1 of the second grinding bars 26B, 36B. In other embodiments (not shown), the first grinding bars 26A, 36A can be radially spaced apart from the second grinding bars 26B, 36B by a certain distance.

[0071] Referring to Figure 4A , Figure 5A and Figure 7 , the grinding surfaces 24, 34 can include dams 29, 39 disposed in at least a portion of the first grinding grooves 28A, 38A. The dams 29, 39 can include a height that is substantially equal to or less than the height of the adjacent first grinding bars 26A, 36A. The dams 29, 39 are used to transfer wood fibers from the first grinding grooves 28A, 38A so as to engage with the first and second grinding bars 26A, 36A, 26B, 36B.

[0072] Referring to Figure 1 , Figure 4A , Figure 5A and Figure 6A, when supplying a wood pulp slurry containing wood fibers to a frame 66 (e.g., an inlet 16 of a grinder 10), the first grinder bars 26A, 36A are adapted to grind the fibers in the wood pulp slurry, while the second grinder bars 26B, 36B are adapted to break or separate fiber bundles. Grinding can be used to disperse and reduce small fiber flocs, cause external or internal fibrillation to achieve fiber bonding, and / or cut a large number of long wood fibers in the wood pulp slurry to reduce the length of the long wood fibers. However, the grinding process can also cause some wood fibers to reform into small, dense fiber bundles ("flakes"), especially during the grinding of long fibers such as softwood. Fiber bundles can have an adverse effect on the tensile strength, formation, etc. of the final paper product, the formation of seed crystals in the wood pulp fiber filaments that clog downstream components, and / or inhibit the drainage of fluid / water from the fibers during paper product production. Therefore, the flakes should be broken up in a process called "deflaking" after grinding. The term "deflaking" as used herein refers to the process of breaking up the fiber bundles formed during the grinding process. When grinding with a conventional wood pulp grinder, deflaking generally occurs in one or more subsequent grinders, which often operate at low power and are called "tickler" grinders or deflakers. Using separate grinders or deflakers increases the cost and complexity of the system. Additionally, the tickler grinders and associated pipelines and water tanks, as well as the downstream machine chest, may accumulate a certain amount of fibers remaining from previous runs and can continue to form fiber bundles. When grinding different wood pulp slurries together, processing in the tickler grinder may degrade the fiber properties. It is believed that the grinding members 20, 30, 40, 50 according to the present disclosure solve these problems by incorporating grinder bars 26A, 26B, 36A, 36B of different heights, thereby enabling grinding and deflaking to be performed within a single grinder 10.

[0073] The first maximum height H1 of the first grinder bars 26A, 36A is greater than the second maximum height H2, meaning that when the wood fibers pass through at least partially the grinding space 60 defined by the first grinder grooves 28A, 38A and are on the first grinder bars 26A, 36A on the opposing first and second grinding surfaces 24, 34 (see also Figure 8 and Figure 9) When the cutting side edges 126A and 136A are joined, the wood fibers are subjected to high-intensity shear and compression forces. Thus, at least a portion of the grinding space 60 that is at least partially defined by the first grinding machine grooves 28A and 38A and extends from the radially inner position P1 on the grinding surfaces 24 and 34 to the first radially outer position P2 on the grinding surfaces 24 and 34 can at least partially define a grinding zone. In some examples, the radially inner portions 23 and 33 of each grinding body 22 and 32 can define the starting point of the grinding zone. When the ground fibers enter at least a portion of the grinding space 60 that is at least partially defined by the second grinding machine grooves 28B and 38B (e.g., from Figure 6A the approximately first radially outer position P2 to the approximately second radially outer position P3), the second grinding machine bars 26B and 36B include a second maximum height H2, and the intensity of the force applied to the fibers decreases in response to the decrease in height (see also Figure 8 and 9 ). Thus, at least a portion of the grinding space 60 that is at least partially defined by the second grinding machine grooves 28B and 38B and extends from the first radially outer position P2 on the grinding surfaces 24 and 34 to the second radially outer position P3 can at least partially define a defibration zone. The reduced force applied to the fibers in the defibration zone can be considered to break up the fiber bundles formed during the grinding process without further grinding, or with only minimal grinding of the fibers. In the Figure 6A illustrated embodiment, the second grinding machine bars 26B and 36B form an annular ring that defines a defibration zone around the radially outer portions (not separately labeled) of the first and second grinding bodies 22 and 32. It can be considered that, in order to stop the grinding of the fibers and start defibration, the second maximum height H2 of the second grinding machine bars 26B and 36B should be at least about 0.35 mm less than the first maximum height H1 of the first grinding machine bars 26A and 36A. The grinding zone can account for 60% or more of the total area on each grinding surface 24 and 34 that is jointly defined by the grinding zone and the defibration zone.

[0074] In Figure 4B , Figure 5B and Figure 6B illustrated embodiments, each grinding machine bar 26' and 36' can include a first grinding machine bar 26A', 36A', a second grinding machine bar 26B', 36B', a third grinding machine bar 26C, 36C, and a fourth grinding machine bar 26D, 36D. The first grinding machine bars 26A' and 36A' and the second grinding machine bars 26B' and 36B' can be associated with Figure 4A , 5A , 6A and Figure 7The first grinding bars 26A, 36A and the second grinding bars 26B, 36B as shown and described in the present disclosure are substantially similar, however, the distance that the first and second grinding bars 26A', 36A', 26B', 36B' extend radially outwardly may be shorter. The first grinding bars 26A', 36A' may be separated from each other by first grinding grooves 28A', 38A', and the second grinding bars 26B', 36B' may be separated from each other by second grinding grooves 28B', 38B'. The first and second grinding grooves 28A', 38A', 28B', 38B' may have a width W of about 2 mm to about 6 mm G . The third grinding bars 26C, 36C may be separated from each other by third grinding grooves 28C, 38C, and the fourth grinding bars 26D, 36D may be separated from each other by fourth grinding grooves 28D, 38D. As Figure 6B shown, the third grinding bars 26C, 36C include a third maximum height H3 that extends upward from the bottom F3 of the adjacent third grinding grooves 28C, 38C, and the fourth grinding bars 26D, 36D include a fourth maximum height H4 that extends upward from the bottom F4 of the adjacent fourth grinding grooves 28D, 38D, wherein the fourth maximum height H4 is less than the third maximum height H3. The third maximum height H3 may be substantially equal to the first maximum height H1, and the fourth maximum height H4 may be substantially equal to the second maximum height H2. The minimum height difference between H3 and H4 is drawn as D2 in Figure 6B . In some examples, the radially outer portions RO2 of the third grinding bars 26C, 36C may include a step from the third maximum height H3 to the fourth maximum height H4. The third and fourth grinding grooves 28C, 38C, 28D, 38D may have a width W of about 2 mm to about 6 mm G .

[0075] In some examples, the fourth maximum height H4 can be at least 0.35 mm less than the third maximum height H3. In other examples, the fourth maximum height H4 can be at least 0.70 mm less than the third maximum height H3. In further examples, when measured from the bottom F3 of adjacent third grinding grooves 28C, 38C, the third maximum height H3 of the third grinding bars 26C, 36C can be from about 4 mm to about 10 mm. In a specific example, when measured from the bottom F4 of adjacent fourth grinding grooves 28D, 38D, the fourth maximum height H4 of the fourth grinding bars 26D, 36D can be about 0.35 mm to about 1.5 mm less than the third maximum height H3. In another specific example, when measured from the bottom F4 of adjacent fourth grinding grooves 28D, 38D, the fourth maximum height H4 of the fourth grinding bars 26D, 36D can be about 0.7 mm to about 1.5 mm less than the third maximum H3. In further examples, the third grinding bars 26C, 36C and the fourth grinding bars 26D, 36D can include a width (not separately marked) extending between the side edges of the respective grinding bars 26C, 36C, 26D, 36D, which is from about 2 mm to about 8 mm.

[0076] Each first grinding bar 26A', 36A' extends from a radially inner position P on the grinding surfaces 24, 34 1' to a first radially outer position P on the grinding surfaces 24, 34 2' . Each second grinding bar 26B', 36B' extends to a second radially outer position P on the grinding surfaces 24, 34 3' . Each third grinding bar 26C, 36C extends to a third radially outer position P4 on the grinding surfaces 24, 34. Each fourth grinding bar 26D, 36D extends to a fourth radially outer position P5 on the grinding surfaces 24, 34. The fourth radially outer position P5 can be closer to the outermost part of the grinding bodies 22, 32, such as the radial outer edges 27, 37, than the first, second, and third radially outer positions P 2' 、P 3' 、P4. The fourth grinding bars 26D, 36D can include a longitudinal length L1 from about 0.6 cm to about 10 cm and preferably from about 2 cm to about 10 cm.

[0077] In some embodiments, as Figure 4B 、 5B and shown in 6B, the second grinding bars 26B', 36B' and the first grinding bars 26A', 36A' can be integral, such that the second grinding bars 26B', 36B' extend from the first radially outer position P 2' to the second radially outer position P 3' . In some embodiments, as Figure 4B 、5B As shown in FIGS. 6A and 6B, the third grinding bars 26C, 36C and the second grinding bars 26B', 36B' may be integral, such that the third grinding bars 26C, 36C extend from the second radially outer position P 3' to the third radially outer position P4. The fourth grinding bars 26D, 36D and the third grinding bars 26C, 36C may be integral, such that the fourth grinding bars 26D, 36D extend from the third radially outer position P4 to the fourth radially outer position P5. In a specific embodiment, the second grinding bars 26B', 36B' may continuously slope downward from the first radially outer position P 2' to the second radially outer position P 3' . As Figure 6B shown, the second grinding bars 26B', 36B' may include a longitudinal length L1 ranging from about 0.6 cm to about 10 cm, preferably from about 2 cm to about 10 cm. The height of the second grinding bars 26B', 36B' may continuously decrease from the second maximum height H2 to the second minimum height H along substantially the entire longitudinal length L1 2' . In another specific embodiment, as shown by the dashed line in Figure 6B , the second grinding bars 26B', 36B' may extend substantially horizontally from the first radially outer position P 2' to the second radially outer position P 3' , such that the second grinding bars 26B', 36B' are substantially at the second maximum height H2 along substantially the entire longitudinal length L1 of the second grinding bars 26B', 36B'. In a specific embodiment, the fourth grinding bars 26D, 36D may continuously slope downward from the third radially outer position P4 to the fourth radially outer position P5. As Figure 6B shown, the height of the fourth grinding bars 26D, 36D may continuously decrease from the fourth maximum height H4 to the fourth minimum height H along substantially the entire longitudinal length L2 4' . In another specific embodiment, as shown by the dashed line in Figure 6B , the fourth grinding bars 26D, 36D may extend substantially horizontally from the third radially outer position P4 to the fourth radially outer position P5, such that the fourth grinding bars 26D, 36D are at the fourth maximum height H4 along their substantially entire longitudinal length L2. In other embodiments (not shown), the third grinding bars 26C, 36C may be radially spaced apart from the fourth grinding bars 26D, 36D by a certain distance.

[0078] See Figure 4B , Figure 5B and Figure 7, according to the present disclosure, the grinding surfaces 24, 34 may include dams 29, 39 disposed in at least a portion of the first and / or third grinding machine grooves 28A', 38A', 28C, 38C.

[0079] As described for Figure 4A , Figure 5A and Figure 6A the first and second grinding machine bars 26A, 36A, 26B, 36B in Figure 4B , Figure 5B and Figure 6B the first grinding machine bars 26A', 36A' in are adapted to grind wood fibers, while Figure 4B , Figure 5B and Figure 6B the second grinding machine bars 26B', 36B' in are adapted to break wood fibers. According to the present disclosure, the third grinding machine bars 26C, 36C are adapted to grind wood fibers (similar to the first grinding machine bars 26A', 36A'), while the fourth grinding machine bars 26D, 36D are adapted to break fiber bundles (similar to the second grinding machine bars 26B', 36B').

[0080] See Figure 1 , Figure 4B , Figure 5B and Figure 6B , according to the present disclosure, those portions of the grinding space 60 that are at least partially defined by the first grinding machine grooves 28A', 38A' and the third grinding machine grooves 28C, 38C and extend on the grinding surfaces 24, 34 from a radially inner position P 1' to a first radially outer position P 2' and from a second radially outer position P 3' to a third radially outer position P4 may respectively at least partially define first and second grinding zones. According to the present disclosure, those portions of the grinding space 60 that are at least partially defined by the second grinding machine grooves 28B', 38B' and the fourth grinding machine grooves 28D, 38D and extend on the grinding surfaces 24, 34 from the first radially outer position P 2' to the second radially outer position P 3'Those extending from the third radially outer position P4 to the fourth radially outer position P5 may respectively at least partially define the first and second delamination zones. It can be considered that in order to stop grinding the fibers and start delaminating, the second maximum height H2 of the second grinding bars 26B', 36B' should be at least about 0.35 mm less than the first maximum height H1 of the first grinding bars 26A', 36A'. Similarly, it can be considered that in order to stop grinding the fibers and start delaminating, the fourth maximum height H4 of the fourth grinding bars 26D, 36D should be at least about 0.35 mm less than the third maximum height H3 of the third grinding bars 26C, 36C. The first and second grinding zones may account for 60% or more of the total area defined by the first and second grinding zones and the delamination zones on each grinding surface 24, 34.

[0081] Figure 8 and Figure 9 are partial cross-sectional views of the first and second grinding elements 20, 30 / 130 of the first and second grinding bodies 22, 32 / 132 according to the present disclosure. The first grinding member 20 is spaced apart from the second grinding member 30 and is positioned adjacent to and opposite the second grinding member 30 (see Figure 1 ). In the Figure 8 illustrated embodiment, the grinding body according to the present invention, such as the first grinding body 22, is paired with a conventional grinding body 132. The first grinding body 22 includes a first grinding bar 26A, a first grinding groove 28A, a second grinding bar 26B, and a second grinding groove 28B, which may correspond to the first and second grinding bars 26A, 26B and the first and second grinding grooves 28A, 28B described in the present disclosure for Figure 4A , 4B , 6A, 6B and Figure 7 . It can be understood that Figure 8 the features described for the first and second grinding bars 26A, 26B and the first and second grinding grooves 28A, 28B are respectively equivalently applied to the third and fourth grinding bars 26C, 26D and the third and fourth grinding grooves 28C, 28D described in the present disclosure (see Figure 4B , 5B and 6B). The conventional grinding body 132 includes a conventional grinding bar 136 and a grinding groove 138, and the conventional grinding bar 136 has a uniform height along its substantially entire longitudinal length. In other embodiments (not shown), the non-rotating stator member (e.g., the first grinding member 20) may include a conventional grinding bar having a uniform height along substantially the entire length, and the rotating rotor member, such as the second grinding member 30, may include the grinding bars 26A, 26B and the grinding grooves 28A, 28B according to the present disclosure (see Figure 1 ).

[0082] In Figure 8defines the outer surface S of the first grinding bar 26A 26A and the outer surface S of the conventional grinding bar 136 136 The first gap G1 therebetween. In an example where the second grinding bar 26B continuously slopes downward, a second gap G2 can be defined between the outer surface S 26B of the second grinding bar 26B and the outer surface of the conventional grinding bar 136, where G2 is greater than G1. In an example where the second grinding bar 26B extends substantially horizontally (shown by a dashed line in Figure 8 ), a third gap G3 can be defined between the outer surface S 26B' of the second grinding bar 26B and the outer surface S 136 of the conventional grinding bar 136, where G3 is greater than G1. As Figure 8 shown, in an embodiment where one of the second grinding bars (e.g., the second grinding bar 26B) is inclined, the distance between the outer surface S 26B of the second grinding bar 26B and the outer surface S 136 of the conventional grinding bar 136 can continuously increase from the minimum distance corresponding to the third gap G3 to the maximum distance corresponding to the second gap G2 along at least a portion of the longitudinal length of the second grinding bar 26B (not marked; see Figure 6A and 6B ).

[0083] In Figure 9 the shown embodiment, a grinding body according to the present invention (e.g., the first grinding body 22) is paired with another grinding body according to the present invention (e.g., the second grinding body 32). The first grinding body 22 includes the first grinding bar 26A, the first grinding groove 28A, the second grinding bar 26B, and the second grinding groove 28B, which can correspond to the first and second grinding bars 26A, 26B and the first and second grinding grooves 28A, 28B described in the present disclosure for Figure 4A , 4B , 6A, 6B and Figure 7 . The second grinding body 32 includes the first grinding bar 36A, the first grinding groove 38A, the second grinding bar 36B, and the second grinding groove 38B, which can correspond to the first and second grinding bars 36A, 36B and the first and second grinding grooves 38A, 38B described in the present disclosure for Figure 5A , 5B , 6A, 6B and Figure 7 . It can be understood that Figure 9Those features described with respect to the first and second grinding bars 26A, 26B, 36A, 36B and the first and second grinding grooves 28A, 28B, 38A, 38B are equivalently applied, respectively, to the third and fourth grinding bars 26C, 26D and the third and fourth grinding grooves 28C, 28D described in the present disclosure (see Figure 4B , 5B , 6B).

[0084] A first gap G1 is defined between the outer surface S 26A of the first grinding bar 26A of the first grinding body 22 and the outer surface S 36A of the first grinding bar 36A of the second grinding body 32. In an example where both the second grinding bar 26B of the first grinding body 22 and the second grinding bar 36B of the second grinding body 32 continuously slope downward, a gap G4 can be defined between the outer surface S 26B of the second grinding bar 26B and the outer surface S 36B of the second grinding bar 36B of the second grinding body 32, where G4 is greater than G1. In an example where one of the second grinding bars (e.g., the second grinding bar 26B of the first grinding body 22) continuously slopes downward and the other of the second grinding bars (e.g., the second grinding bar 36B of the second grinding body 32) extends substantially horizontally ( Figure 9 as shown by the dashed line in 26B ), a gap G5 can be defined between the outer surface S 36B' of the second grinding bar 26B and the outer surface S Figure 9 of the second grinding bar 36B, where G5 is greater than G1. In an example where both the second grinding bar 26B of the first grinding body 22 and the second grinding bar 36B of the second grinding body 32 extend substantially horizontally ( 26B' as shown by the dashed line in 36B' ), a gap G6 can be defined between the outer surface S

[0085] of the second grinding bar 26B and the outer surface S Figure 9 of the second grinding bar 36B, where G6 is greater than G1. In some specific examples, G4 is greater than G5 and G5 is greater than G6. 26B , S 26B' , S 36B , S 36B' ), the distance between can be along at least a portion of the longitudinal length of one or both of the respective second grinding bars 26B, 36B (not marked; see Figure 6A and 6B) Continuously increase. For example, when a grinding body (e.g., the first grinding body 22) includes the inclined second grinding bar 26B, the distance between the outer surfaces S 26B and S 36B' can increase from the minimum distance corresponding to the gap G6 to the maximum distance corresponding to the third gap G5. When both grinding bodies 22, 32 include the inclined second grinding bars 26B, 36B, the distance between the outer surfaces S 26B and S 36B can increase from the minimum distance corresponding to the gap G6 to the maximum distance corresponding to the gap G4.

[0086] In Figure 8 and Figure 9 all the illustrated embodiments, as the rotatable grinding member (e.g., the first grinding member 20; see Figure 1 ) rotates relative to the stationary grinding member (e.g., the second grinding member 30 / 130; see Figure 1 ), the wood pulp slurry including wood fibers is supplied to the frame 66 of the grinder 10 (see Figure 1 ), such as the inlet 16, and enters the grinding space 60 defined between the first and second grinding bodies 22, 32 / 132. Referring to Figure 8 , as the wood fibers enter at least a portion of the grinding space 60 defined by the first grinding grooves 28A of the first grinding body 22 and the grinding grooves 138 of the second grinding body 132, the first and second grinding bodies 22, 132 are spaced apart to define a first gap G1 between the first grinding bar 26A of the first grinding body 22 and the conventional grinding bar 136 of the second grinding body 132, such that the grinding bars 26A and 136 interact with each other to grind the wood fibers as described in the present disclosure. It is considered that in order for grinding to occur, the first gap G1 should be less than about 0.9 mm, preferably between about 0.2 mm and about 0.9 mm.

[0087] Continuing to refer to Figure 8, as the wood fibers enter the at least partially defined by the second grinding machine groove 28B of the first grinding body 22 and the grinding machine groove 138 of the second grinding body 132 in the grinding space 60, the distance between the second grinding machine bar 26B of the first grinding body 22 and the grinding machine bar 136 of the second grinding body 132 increases, so that it can be considered that the grinding stops and the fibrillation starts. In the embodiment where the second grinding machine bar 26B continuously slopes downward, this distance increases from the first gap G1 to the second gap G2. In the embodiment where the second grinding machine bar 26B extends substantially horizontally, this distance increases from the first gap G1 to the third gap G3. It can be considered that, in order for fibrillation to occur, the distance between the second grinding machine bar 26B of the first grinding body 22 and the grinding machine bar 136 of the second grinding body 132, that is, G2 or G3, should be between about 0.9 mm and about 1.5 mm.

[0088] See Figure 9 , as the wood fibers enter the at least partially defined by the first grinding machine grooves 28A, 38A of the first and second grinding bodies 22, 32 in the grinding space 60, the first and second grinding bodies 22, 32 are spaced apart to define the first gap G1 between the first grinding machine bars 26A, 36A, such that the grinding machine bars 26A, 36A interact with each other to grind the wood fibers as described in the present disclosure. As the wood fibers enter the at least partially defined by the second grinding machine grooves 28B, 38B of the first and second grinding bodies 22, 32 in the grinding space 60, the distance between the second grinding machine bar 26B of the first grinding body 22 and the second grinding machine bar 36B of the second grinding body 32 increases to one of the gaps G4, G5 or G6, such that the grinding stops and the fibrillation starts. It can be considered that, in order for grinding to occur, the first gap G1 should be less than about 0.9 mm, preferably between about 0.2 mm and about 0.9 mm, and in order for fibrillation to occur, the gaps G4, G5, G6 should be between about 0.9 mm and about 1.5 mm.

[0089] See Figure 1 , Figure 6A , Figure 6B , Figure 8 and Figure 9, the gaps G1 and G2, G3, G4, G5, G6 defined between the grinding members 22, 32 / 132 can be adjusted by applying an axial pressure to at least one of the first or second grinding members 20, 30, for example, by means of a second motor 76 coupled to the movable support frame 68 via a screw jack (not shown). For a single-disk grinder, the second grinding member 30 can be directly coupled to the movable support frame 68 such that as the movable support frame 68 is moved via the second motor 76 and the screw jack, the second grinding member 30 moves with the movable support frame 68. For the double-disk grinder 10, the second grinding member 30 moves as described above, i.e., as the screw jack rotates in a first direction, causing the movable support frame 68 and the fourth grinding member 50 to move inwardly towards the third grinding member 40. The fourth grinding member 50 then applies an axial force to the slurry passing through the second grinding space 62, which in turn applies an axial force to the third grinding member 40, causing the third grinding member 40, the support 70, and the second grinding member 30 to move inwardly towards the first grinding member 20.

[0090] By adjusting the positioning of the second grinding member 30 relative to the first grinding member 20 via the second motor 76 (manually controlled or controlled via a controller / processor coupled to the second motor 76) and the screw jack, the gap G1 defined between the grinder bars 26A, 36A, 136 is maintained at a substantially constant gap value such that the amount of power that needs to be input / generated by the first motor 74 (manually controlled or controlled via a controller / processor coupled to the first motor 74) operating at a predetermined rotational speed to process a certain amount of wood pulp passing through the grinding space 60 is maintained at a predetermined input power level, which is monitored by the operator or the controller / processor controlling the first motor 74. For example, if the wood pulp passes through the grinding space 60 of a Twinflo IIIB low consistency grinder with a flow rate of 151 gallons per minute and a diameter of 20 inches and the first motor 74 operates at a constant rotational speed of 800 RPM, then the second motor 76 is controlled to move the second grinding member 30 relative to the first grinding member 20 until the power input by the first motor 74 equals 114 kilowatts. When the power input by the first motor 74 equals 114 kilowatts, the gap size between the first and second grinding members 20, 30 is estimated to be 0.57 mm.

[0091] Continuing to refer to Figure 1 , Figure 6A , Figure 6B , Figure 8 and Figure 9, it can be considered that the gaps G2, G3, G4, G4, G5, G6 required for achieving defibration can be changed according to the load or flow rate experienced by the grinding media 22, 32 / 132 (i.e., liters per minute of wood pulp slurry flowing through the grinding space 60). For example, when the grinding media 22, 32 / 132 are under light load, when the fibers enter the part of the grinding space 60 that is at least partially defined by the second grinder grooves 28B / 28B', 38B / 38B', for example when the wood fibers move past Figure 6A and 6B the first radially outermost position P2 / P shown 2' and / or the third radially outermost position P4, the grinding of the wood fibers can be almost immediately stopped and defibration can start. When the grinding media 22, 32 / 132 are under heavy load, at least along the part of the grinding space 60 that is at least partially defined by the second grinder grooves 28B / 28B', 38B / 38B', some grinding of the wood fibers continues.

[0092] In the case where the grinding media 22, 32 / 132 are under heavy load, an embodiment in which one or both of the second grinder bars 26B / 26B' of the first grinding media 22 and the second grinder bars 36B / 36B' of the second grinding media 32 continuously slope downward may be particularly advantageous for ensuring that there is a sufficient distance between the grinder bars 26B / 26B' and 136 / 36B / 36B' along at least the part of the grinding space 60 that is at least partially defined by the second grinder grooves 28B / 28B', 38B / 38B' to allow the grinding to stop and defibration to start. Additionally, the grinding surfaces 24, 34 of the grinding media 22, 32 will wear and deteriorate over time. In particular, the first and third grinder bars 26A / 26A', 26C, 36A / 36A', 36C that perform most of the high-intensity, high-energy grinding may wear faster than the second and fourth grinder bars 26B / 26B', 26D, 36B / 36B', 36D that perform defibration, and the intensity and energy of defibration are generally lower than that of grinding. The positions of the grinding media 22, 32 / 132 can be adjusted as described in the present disclosure so that when the outer surfaces S 26A 、S 36AWhen starting to wear, the first gap G1 between the first and third grinding bars 26A / 26A', 26C, 36A / 36A', 36C is maintained at a substantially constant value. However, the gaps G2, G3, G4, G4, G5, G6 between the second and fourth grinding bars 26B / 26B', 26D, 36B / 36B', 36D may be non-adjustable. Therefore, in embodiments where one or both of the second grinding bars 26B / 26B', 36B / 36B' and / or one or both of the fourth grinding bars 36B / 36B, 36D are inclined, it is considered that when the first and third grinding bars 26A / 26A', 26C, 36A / 36A', 36C are worn, the transition between the grinding zone and the defibration zone varies radially outwards along the longitudinal lengths (not marked; see Figure 6A and 6B ) of the second and fourth grinding bars 26B / 26B', 26D, 36B / 36B', 36D.

[0093] Figure 10 and Figure 11 are top views of partial grinding surfaces of a first grinding body 22' and a second grinding body 32' according to another embodiment of the present disclosure. See Figure 1 , Figure 10 and Figure 11 , the first and second grinding bodies 22', 32' may be part of the grinding members (e.g., the first and second grinding members 20, 30) described in the present disclosure for use in Figure 1 a disk grinder 10 such as that depicted in a pulp grinder. Each grinding member 20, 30 including the first and second grinding bodies 22', 32' respectively may be associated with a main support frame including a fixed support frame 66 fixed to a first housing member 12 and a movable support frame 68. One grinding member, such as the first grinding member 20 including the first grinding body 22', may be mounted to the support frame 66 of the grinder 10 so as to define a non-rotating stator member. Another grinding member, such as the second grinding member 30 including the second grinding body 32', may be mounted to a support 70 that rotates with a shaft 72 and defines a rotor associated with the main support frame such that rotation of the rotor causes the second grinding member 30 to move relative to the first grinding member 20. Third and fourth grinding members (not shown) may also be provided, having third and fourth grinding bodies similar to the first and second grinding bodies 22', 32'.

[0094] As Figure 10As shown, the first grinding body 22' includes a plurality of components 22A'-22C', which can be bolted or otherwise attached together to form a disc-shaped grinding body 22' including a radially outer edge 27'. Each component 22A'-22C' includes a plurality of elongated grinding bars 26' separated from each other by grinding grooves 28'. Although not shown in Figure 10 , it can be understood that other components (not labeled) of the first grinding body 22' will similarly include grinding bars 26' and grinding grooves 28'. The grinding bars 26' extend radially outward from the radially inner part 23' of the first grinding body 22' towards the radially outer edge 27'. Each component 22A'-22C' of the first grinding body 22' may include one or more radially extending pie-shaped sections, the pie-shaped sections including at least one first pie-shaped section 22B-1 and at least one second pie-shaped section 22B-2.

[0095] As Figure 11 shown, the second grinding body 32' includes a corresponding plurality of components 32A'-32C', which can be bolted or otherwise attached together to form a disc-shaped grinding body 32' including a radially outer edge 37'. Each component 32A'-32C' includes a plurality of elongated grinding bars 36' separated from each other by grinding grooves 38'. Although not shown in Figure 11 , it can be understood that other components (not labeled) of the second grinding body 32' will similarly include grinding bars 36' and grinding grooves 38'. The grinding bars 36' extend radially outward from the radially inner part 33' of the second grinding body 32' towards the radially outer edge 37'. Each component 32A'-32C' of the second grinding body 32' may include one or more radially extending pie-shaped sections, the pie-shaped section including at least one first pie-shaped section 32B-1 and at least one second pie-shaped section 32B-2. Although not discussed in detail here, Figure 1 the structures of the third and fourth grinding bodies 42, 52 of

[0096] Figure 10 and Figure 11 at least one of the first and second grinding bodies 22', 32' of Figure 12A and 12B are partial cross-sectional views, wherein, Figure 10 andFigure 11 The first and second grinding elements 22', 32' are spaced apart from each other, positioned adjacent to and facing each other (see Figure 1 ). In Figure 12A , the first grinding bar 26-1 may be located on the grinding surface 24-1 (also referred to herein as the first grinding surface) of at least one first disc-shaped section 22B-1 of the first grinding element 22', which is spaced apart from the third grinding bar 36-1, positioned adjacent to and facing the third grinding bar 36-1, and the third grinding bar 36-1 may be located on the grinding surface 34-1 (also referred to herein as the third grinding surface) of at least one third disc-shaped section 32B-1 of the second grinding element 32'. In Figure 12B , the second grinding bar 26-2 may be located on the grinding surface 24-2 (also referred to herein as the second grinding surface) of at least one second disc-shaped section 22B-2 of the first grinding element 22', which is spaced apart from the fourth grinding bar 36-2, positioned adjacent to and facing the fourth grinding bar 36-2, and the fourth grinding bar 36-2 may be located on the grinding surface 34-2 (also referred to herein as the fourth grinding surface) of at least one fourth disc-shaped section 32B-2 of the second grinding element 32'.

[0097] See Figure 10 , 11 and 12A, the first grinding bar 26-1 is separated from each other by the first grinding grooves 28-1 and may include a first maximum height H extending upward from the bottom F of the respective adjacent first grinding grooves 28-1 1' . The third grinding bar 36-1 is separated from each other by the third grinding grooves 38-1 and may include a third maximum height H extending upward from the bottom F of the respective adjacent third grinding grooves 38-1 1' . As 3' shown in 3' , the first and third grinding bars 26-1, 36-1 may be substantially similar to each other, and the first and third maximum heights H Figure 12A , H 1' , H 3' may be substantially equal.

[0098] See Figure 10 , 11 and 12B, the second grinding bar 26-2 is separated from each other by the second grinding grooves 28-2 and may include a second maximum height H extending upward from the bottom F of the adjacent second grinding grooves 28-2 2' . The fourth grinding bar 36-2 is separated from each other by the fourth grinding grooves 38-2 and may include a fourth maximum height H extending upward from the bottom F of the adjacent fourth grinding grooves 38-2 2' . The fourth maximum height H extends upward from the bottom F of the adjacent fourth grinding grooves 38-2 4' and may include a fourth maximum height H extending upward from the bottom F of the adjacent fourth grinding grooves 38-24' As shown in Figure 12B , the second and fourth grinding bars 26-2, 36-2 can be substantially similar to each other, and the second and fourth maximum heights H 2' , H 4' can be substantially equal. All the grinding bars 26-1, 26-2, 36-1, 36-2 within each pie-shaped section 22B-1, 22B-2, 32B-1, 32B-2 can include the same height relative to each other.

[0099] The second maximum height H of the second grinding bar 26-2 2' can be less than the first maximum height H of the first grinding bar 26-1 1' . In some examples, when measured from the bottom F of the adjacent second grinding groove 28-2 2' , the second maximum height H 2' can be at least 0.35 mm less than the first maximum height H 1' . In other examples, when measured from the bottom F of the adjacent second grinding groove 28-2 2' , the second maximum height H 2' can be at least 0.70 mm less than the first maximum height H 1' . In additional examples, when measured from the bottom F of the respective adjacent first grinding groove 28-1 1' , the first maximum height H of the first grinding bar 26-1 1' can be from about 4 mm to about 10 mm. In a specific example, when measured from the bottom F of the respective adjacent second grinding groove 28-2 2' , the second maximum height H of the second grinding bar 26-2 2' can be about 0.35 mm to about 1.5 mm less than the first maximum height H 1' . In another specific example, when measured from the bottom F of the respective adjacent second grinding groove 28-2 2' , the second maximum height H of the second grinding bar 26-2 2' can be about 0.7 mm to about 1.5 mm less than the first maximum height H 1' . In further examples, the first grinding bar 26-1 and the second grinding bar 26-2 can include a width extending between the side edges of the respective grinding bars 26-1, 26-2, which is from about 2 mm to about 8 mm (not shown; see Figure 7 ). The fourth maximum height H of the fourth grinding bar 36-2 4' can correspond to the second maximum height H 2' , which can be less than the third maximum height H of the third grinding bar 36-1 3' , and the third maximum height H 3'may correspond to a first maximum height H 1' .

[0100] See Figure 1 , Figure 10 , Figure 11 , Figure 12A and Figure 12B , when the second grinding member 30 rotates relative to the first grinding member 20, the grinding surface 34-1 of at least one third pie-shaped section 32B-1 of the second grinding body 32' will pass over the grinding surface 24-1 of at least one first pie-shaped section 22B-1 of the first grinding body 22', and the grinding surface 34-2 of at least one fourth pie-shaped section 32B-2 of the second grinding body 32' will pass over the grinding surface 24-2 of at least one second pie-shaped section 22B-2 of the first grinding body 22'. When the wood pulp slurry is supplied to the frame 66 of the grinder 10 (e.g., the inlet 16) and passes through the grinding space 60, and the grinding surface 34-1 of at least one third pie-shaped section 32B-1 of the second grinding body 32' passes over the grinding surface 24-1 of at least one first pie-shaped section 22B-1 of the first grinding body 22', the third grinder bar 36-1 including the third maximum height H 3' will be positioned opposite the first grinder bar 26-1 including the first maximum height H 1' such that the first grinder bar 26-1 and the third grinder bar 36-1 grind a large number of wood fibers. When the grinding surface 34-2 of at least one fourth pie-shaped section 32B-2 of the second grinding body 32' passes over the grinding surface 24-2 of at least one second pie-shaped section 22B-2 of the first grinding body 22', the fourth grinder bar 36-2 including the fourth maximum height H 4' will be positioned opposite the second grinder bar 26-2 including the second maximum height H 2' such that the second grinder bar 26-2 and the fourth grinder bar 36-2 break or separate a plurality of wood fiber bundles in the wood pulp slurry, as described in the present disclosure. When the grinding surface 34-1 of at least one third pie-shaped section 32B-1 of the second grinding body 32' passes over the grinding surface 24-2 of at least one second pie-shaped section 22B-2 of the first grinding body 22', and the grinding surface 34-2 of at least one fourth pie-shaped section 32B-2 of the second grinding body 32' passes over the grinding surface 24-1 of at least one first pie-shaped section 22B-1 of the first grinding body 22', low-intensity grinding may occur.

[0101] As Figure 10 and Figure 11As shown, in some examples, one or more of the components 22A'-22C' and 32A'-32C' of each of the grinding elements 22' and 32' may each include three radially extending disc-shaped sections 22B-1, 22B-2, 22B-3 and 32B-1, 32B-2, 32B-3. In some specific examples, two sections (e.g., 22B-1, 22B-3 and 32B-1, 32B-3) may include grinding bars having one of the first or second maximum heights H 1' , H 2' , and one section (e.g., 22B-2 and 32B-2) may include grinding bars having the other of the first or second maximum heights H 1' , H 2' , where the second maximum height H 2' is less than the first maximum height H 1' . For example, sections 22B-1, 22B-3 may include the first grinding bar 26-1, sections 32B-1, 32B-3 may include the third grinding bar 36-1, section 22B-2 may include the second grinding bar 26-2, and section 32B-2 may include the fourth grinding bar 36-2. In other examples (not shown), one or more of the components 22A'-22C' and 32A'-32C' may each include only two sections of the grinding bar, or may each include a grinding bar of four or more sections. In additional examples (not shown), one or more of the components 22A'-22C' and 32A'-32C' may not include separate sections, such that the entire component includes a grinding bar having one height. It will be appreciated that a grinding element (e.g., one of the grinding elements 22' and 32') according to the present disclosure may be paired with a grinding element including conventional grinding bars (e.g., grinding bars all having the same height).

[0102] It is considered that, in order for grinding to occur, the gap between the opposing first and third grinding bars 26-1, 36-1 should be less than about 0.9 mm, preferably between about 0.2 mm and about 0.9 mm, and in order for disintegration to occur, the gap between the opposing second and fourth grinding bars 26-2, 36-2 should be from about 0.9 mm to about 1.5 mm.

[0103] Figure 13 and Figure 14 are respectively plan views of portions of the first grinding surface 224 of the first grinding element 222 and the second grinding surface 234 of the second grinding element 232 according to another embodiment of the present disclosure. Referring to Figure 1 , Figure 13 and Figure 14 , the first and second grinding elements 222, 232 may respectively be part of grinding members such as the grinding members 20, 30, etc. described in the present disclosure, for example, inFigure 1 It is used in wood pulp grinders such as the disc grinder 10 depicted. Each grinding member 20, 30 respectively including first and second grinding elements 222, 232 can be associated with a main support frame including a fixed support frame 66 fixed to the first housing member 12 and a movable support frame 68. One grinding member (e.g., the first grinding member 20 including the first grinding element 222) can be mounted on the support frame 66 of the grinder 10 to define a non-rotating stator member. The other grinding member (e.g., the second grinding member 30 including the second grinding element 232) can be mounted on a support 70 that rotates together with the shaft 72 and defines a rotor associated with the main support frame, such that the rotation of the rotor causes the second grinding member 30 to move relative to the first grinding member 20.

[0104] As Figure 13 shown, the first grinding element 222 includes a plurality of components (not individually labeled; see Figure 2 and 3 ), which can be bolted or otherwise attached together to form a disc-shaped grinding element 222 including a radial outer edge 227. The first grinding surface 224 includes a plurality of elongated first grinding machine bars 226 separated from each other by first grinding machine grooves 228. The first grinding machine bars 226 extend radially outward from a radially inner portion 223 of the first grinding element 222 toward the radial outer edge 227. The first grinding machine bars 226 can be inclined at various angles as Figure 13 shown, and each component of the grinding element 222 can include one or more sections (not labeled) of grinding machine bars 226 inclined in different directions. The first grinding element 222 further includes one or more annular rows or rings of teeth 400 located between the first grinding machine bars 226 and the radial outer edge 227 of the first grinding element 222. Although not shown in Figure 13 , it can be understood that other components (not labeled) of the first grinding element 222 will similarly include grinding machine bars 226, grinding machine grooves 228, and teeth 400.

[0105] As Figure 14 shown, the second grinding element 232 includes a plurality of components (not individually labeled; see Figure 2 and 3 ), which can be bolted or otherwise attached together to form a disc-shaped grinding element 232 including a radial outer edge 237. The second grinding surface 234 includes a plurality of elongated second grinding machine bars 236 separated from each other by second grinding machine grooves 238. The second grinding machine bars 236 extend radially outward from a radially inner portion 233 of the second grinding element 232 toward the radial outer edge 237. The second grinding machine bars 236 can be as Figure 14shown at various angles of inclination, and each component of the grinding body 232 may include one or more segments (not labeled) of the grinding bar 236 that are inclined in different directions. The second grinding body 232 also includes one or more annular rows or circles of teeth 400 located between the second grinding bar 236 of the second grinding body 232 and the radially outer edge 237. Although not shown in Figure 14 it will be understood that other components (not labeled) of the second grinding body 232 will similarly include the grinding bar 236, the grinding grooves 238, and the teeth 400. Additionally, although not discussed in detail here, the structure of the grinding surfaces 44, 54 of the third and fourth grinding bodies 42, 52 in Figure 1 may respectively include structures that are substantially similar to the grinding surfaces 224, 234 of the first and second grinding bodies 222, 232 described in this disclosure.

[0106] Figure 15 and Figure 16 are respectively Figure 13 and Figure 14 detailed views of portions of the first and second grinding surfaces 224, 234. Figure 17 is a partial cross-sectional view of the first grinding bar 226 and the teeth 400B, and the second grinding bar 236 and the teeth 400A, 400C. The first grinding bar 226 and the teeth 400B may be located on the first grinding body 222 of Figure 13 and Figure 15 The second grinding bar 236 and the teeth 400A, 400C may be located on the second grinding body 232 of Figure 14 and Figure 16 wherein the first grinding body 222 is spaced apart from the second grinding body 232, positioned adjacent to and facing the second grinding body 232 so as to define a grinding space 260 therebetween. Referring to Figures 15 - 17 , the first grinding surface 224 includes the first grinding bars 226 separated from each other by the first grinding grooves 228, and the second grinding surface 234 includes the second grinding bars 236 separated from each other by the second grinding grooves 238. As described in this disclosure, one or both of the first and second grinding surfaces 224, 234 may include dams 229, 239 disposed in at least a portion of the first and second grinding grooves 228, 238. Each of the first and second grinding bars 226, 236 extends from a radially inner position P 100 to a first radially outer position P 200 . In some examples, the radially inner position P 100 may include respective radially inner portions 223, 233 (see Figure 13 and 14) at or near the location. The first and second grinding bars 226, 236 may respectively include a width W extending between the side edges of the respective grinding bars 226, 236 226 , W 236 , which is about 2 mm to about 8 mm.

[0107] The first grinding surface 224 includes a first tooth 400B located between the radially outer edge RO of the first grinding bar 226 226 and the radially outer edge 227 of the first grinding body 222. The first tooth 400B extends to a third radially outer position on the first grinding surface 224, such as P 400 , wherein the third radially outer position P 400 is closer to the outermost part of the first grinding body 222, such as the radially outer edge 227, than the first radially outer position P of the first grinding bar 226 200 . The second grinding surface 234 includes second teeth 400A, 400C located between the radially outer edge RO of the second grinding bar 236 236 and the radially outer edge 237 of the second grinding body 232. The second teeth 400A, 400C extend on the second grinding surface 234 to a second or fourth radially outer position, such as P 300 or P 500 , wherein the second and fourth radially outer positions P 300 , P 500 are closer to the outermost part of the second grinding body 232, such as the radially outer edge 237, than the first radially outer position P of the second grinding bar 236 200 .

[0108] Continuing to refer to Figures 15 - 17 , the teeth 400A - 400C may be arranged in concentric circles and may project substantially perpendicularly towards each other from the respective grinding surfaces 224, 234. The circle including the first tooth 400B is spaced from the radially outer edge RO of the first grinding bar 226 226 by a first substantially flat area 282 and is spaced from the radially outer edge 227 of the grinding body 222 by a second substantially flat area 284. The circle including the second tooth 400A is spaced from the radially outer edge RO of the second grinding bar 236 236 by a first substantially flat area 286 and is spaced from the circle including the second tooth 400C by a second substantially flat area 288. At Figures 15 to 17In the illustrated embodiment, the first grinding surface 224 of the first grinding body 222 includes a concentric row / circle of first teeth 400B, and the second grinding surface 234 of the second grinding body 232 includes two concentric rows / circles of second teeth 400A, 400C. Among them, the first and second teeth 400A-400C are arranged on their respective grinding surfaces 224, 234 such that the first teeth 400B mesh with the second teeth 400A, 400C. In other embodiments (not shown), the first grinding surface 224 may include two or more concentric circles, and the second grinding surface 234 may include a concentric row of teeth, or three or more concentric circles of teeth. In all embodiments, one of the grinding bodies will include one less row of teeth than the other grinding body, and the teeth are arranged on each grinding body such that the teeth from one grinding body mesh with the teeth of the other grinding body, as is known in the art.

[0109] It will be appreciated that the teeth 400A-400C may include any suitable shape and / or size known in the art. As Figure 17 shown for the tooth 400A, in some examples, each of the first and second teeth 400A-400C may include a shape that is substantially pyramidal or trapezoidal, having a base 402, a radially inward surface 404, a radially outward surface 406, a side surface (not separately labeled) that is slightly inwardly inclined toward the central axis (not labeled) of the tooth 400A, and a generally flat outer surface 408. The radially inward and outward surfaces 404, 406 of each tooth 400A-400C may slope from the base 402 toward its respective outer surface 408. The outer surface 408 of each tooth 400A-400C may be substantially parallel to the plane of the respective substantially flat regions 282, 284, 288 that is opposite to the teeth 400A-400C. In other examples (not shown), each of the first and second teeth 400A-400C may include a shape that is substantially triangular, rectangular, or any other suitable geometric shape. As Figures 15 - 17 shown, the base 402 of the teeth 400A-400C may include a radial dimension that is greater than the circumferential dimension, but in other embodiments (not shown), the base 402 may include a radial dimension that is less than the circumferential dimension. In some cases, at least a portion of the base 402 of the teeth 400A-400C may include a longitudinal length (not labeled) of at least 0.6 cm, i.e., in the radial direction, and in some specific cases, the longitudinal length may be between about 0.6 cm and about 2 cm. In other cases, at least a portion of the base 402 of the teeth 400A-400C may include a width (not labeled) in the circumferential direction that is substantially equal to the width of one grinding bar 226, 236 (e.g., W 226 、W 236 ) and the width W of an adjacent groove 228, 238G Combined width. The width W G can be from about 2 mm to about 6 mm. For example, the base 402 of the teeth 400A - 400C can be at least about 10 mm in the circumferential direction. In other cases, the base 402 of the teeth 400A - 400C can be about 10 mm to 20 mm in the circumferential direction. Additionally, one or more of the radially inwards and outwards surfaces 404, 406 or sides of one or more of the teeth 400A - 400C can include one or more radially extending protrusions that can affect the interaction of the teeth 400A - 400C with the wood fibers in order to separate the wood fiber bundles. The teeth 400A - 400C can have a structure similar to that shown in U.S. Patent No. 8,342,437B2, the disclosure of which is incorporated herein by reference.

[0110] As Figure 17 shown, the first grinding bar 226 includes a first height H extending upward from the bottom F of the adjacent first grinding groove 228 100 The second grinding bar 236 includes a second height H extending upward from the bottom F of the adjacent second grinding groove 238 100 In some examples, the first height H of the first grinding bar 226 and the second grinding bar 236 200 and the second height H 200 can be substantially equal to each other and can be from about 4 mm to about 10 mm. The first grinding bodies 222 and the second grinding bodies 232 are separated by a first gap G defined between the outer surface S of the first grinding bar 226 100 and the outer surface S of the second grinding bar 236 200 A second gap G is defined between the generally flat outer surface 408 of the teeth 400A - 400C and a corresponding one of the generally flat regions 282, 284, 288 opposite the teeth 400A - 400C, where G 226 can be greater than G 236 In some examples, the height (not labeled) of the teeth 400A - 400C extending upward from the adjacent respective first or second grinding grooves 228, 238 can be from about 8 to 10 mm. As 100 200 200 100 100 can be greater than G 100 In some examples, the height (not labeled) of the teeth 400A - 400C extending upward from the adjacent respective first or second grinding grooves 228, 238 can be from about 8 to 10 mm. As Figure 17 shown, the teeth 400A - 400C mesh with each other such that a part of one or both of the radially inwards or outwards surfaces 404, 406 of each tooth 400A - 400C is in the axial direction (e.g., in Figure 1in the direction of arrow A) overlaps with a part of the radially inward or outward surfaces 404, 406 of the adjacent teeth 400A - 400C. The (one or more) overlapping parts of the teeth 400A - 400C may be defined by a third gap G between the corresponding radially inward or outward surfaces 404, 406 of the teeth 400A - 400C 300 are spaced apart. In some examples, G 300 may be substantially equal to G 200 . In other examples, G 300 may be less than or greater than G 200 .

[0111] See Figure 1 and Figure 17 , when the wood pulp slurry is supplied to the frame of the grinder 10 (e.g., the inlet 16), the wood fibers enter the grinding space 260 at least partially defined by the first and second grinding grooves 228, 238, e.g., from about the first radially inward position P 100 to about the first radially outward position P 200 . According to the present disclosure, the first grinding bar 226 and the second grinding bar 236 interact with each other to grind a large number of wood fibers in the wood pulp. It can be considered that, for grinding to occur, the first gap G 100 should be less than about 0.9 mm, and preferably between about 0.2 mm and about 0.9 mm. The ground wood fibers then enter the part of the grinding space 260 at least partially defined by the corresponding first and second substantially flat regions 282, 284, 286, 288, e.g., from about the first radially outward position P 200 to about the fourth radially outward position P 500 . It can be considered that, for fibrillation to occur, the second gap G 200 and the third gap G 300 should be between about 0.9 mm and about 1.5 mm. According to the present disclosure, the teeth 400A - 400C are adapted to break or separate a plurality of fiber bundles in the wood pulp slurry. G 200 is greater than G 100 , so it can be considered that grinding stops and fibrillation begins at about the first radially outward position P 200 .

[0112] See Figure 1 and Figures 15 - 17 , the grinding surfaces 224, 234 of the grinding bodies 222, 232, especially the outer surfaces S 226 、S 236and the outer surfaces 408 of the teeth 400A - 400C, which may wear over time and degrade in quality. To compensate for such wear, the spacing between the first and second grinding members 20, 30 respectively including the first and second grinding bodies 222, 232 may be readjusted as described in the present disclosure such that the first gap G 100 remains substantially constant. Such adjustment of the first and second grinding bodies 222, 232 may cause the second gap G 200 to decrease because the grinding bars 226, 236 perform a more intense grinding function than the teeth 400A - 400C and generally wear faster. This difference in wear can be accounted for in the selection of the teeth 400A - 400C (e.g., the type(s) of metal for the teeth 400A - 400C, the initial size of the second gap G 200 , the shape of the teeth 400A - 400C, etc.) such that when wood fibers enter that part of the grinding space 260 defined at least in part by the respective first and second substantially flat regions 282, 284, 286, 288, a sufficient second gap G 200 can be maintained to ensure that grinding stops and fibrillation begins. When the grinding bodies 222, 232 are new, the third gap G 300 can be substantially equal to or greater than the second gap G 200 . When the grinding surfaces 224, 234 wear and the grinding members 20, 30 move closer together, the third gap G 300 can decrease until the third gap G 300 is less than the second gap G 200 .

[0113] In all embodiments described in the present disclosure, Figure 1 the grinder 10 may be coupled to a controller (not shown) that receives data regarding one or more fiber properties (such as the number, size, etc. of fiber bundles (also referred to as "wide shives"), fibrillation, Canadian Standard Freeness, fiber length, fiber width, kinks, curls, coarseness, fineness, etc.) measured at one or more locations downstream of the grinder 10 from a fiber analyzer (e.g., MAP Pulp Analyzer (Valmet Corp.)). Based on this data, the controller may control the operation of the grinder 10 as part of a feedback loop. For example, the controller may adjust the spacing between one or more pairs of grinding members 20, 30, 40, 50 to maintain one or more fiber properties within a predetermined target range. In some examples, it can be considered that the controller may also increase or decrease the rotational speed of one or more rotating rotor members (such as the second and third grinding members 30, 40) of the grinder 10 based on this data. In other examples, the controller may, such as by changing the grinding gaps G1, G 100and the sizes of the delamination gaps G2, G3, G4, G5, G6, G 200 , G 300 to control the operation of the grinder 10 to produce ground softwood pulp having fewer than a predetermined number (e.g., 1,000 ppm) of fiber bundles having a specific size (e.g., about 150 to 2,000 microns wide and 0.3 to 40 millimeters long).

[0114] In other examples, the grinding members 20, 30, 40, 50 according to the present disclosure may be installed in one or more of a plurality of grinders arranged in series, wherein each grinder may be substantially similar to Figure 1 the grinder 10. The controller may control the operation of one or more of the plurality of grinders to maintain one or more fiber properties within a predetermined target range. In some specific examples, the grinding members 20, 30, 40, 50 according to the present disclosure may be installed only in the last grinder in the series, while in other examples, the grinding members 20, 30, 40, 50 according to the present disclosure may be installed in two or more grinders.

[0115] Figure 18 is a flow chart showing an exemplary method for processing wood fibers. Although reference is made to Figure 1 the components of the grinder 10 in, it will be understood that the method is not limited to this structure. The method may start at step 500, providing a grinder 10 including at least a first pair of grinding members 20 and 30, 40 and 50. The at least one pair of grinding members may include a first grinding member 20 and a second grinding member 30, the first grinding member 20 including a first grinding body 22 having a first grinding surface 24, and the second grinding member 30 including a second grinding body 32 having a second grinding surface 34. The first grinding surface 24 may include a first grinding bar 26A separated by a first grinder groove 28A and a second grinding bar 26B separated by a second grinder groove 28B, wherein the first grinding bar 26A has a first maximum height H1 extending upward from the bottom F1 of the adjacent first grinder groove 28A, and the second grinding bar 26B has a second maximum height H2 extending upward from the bottom F2 of the adjacent second grinder groove 28B. The second grinding surface 34 may include second member grinding bars 36 separated by second grinder grooves 38. The first grinding member 20 may be spaced apart from the second grinding member 30 to define a grinding space 60 therebetween. At least a portion of the second member grinding bars 36 may be positioned to face the second grinding bars 26B of the first grinding member 20, such that gaps G2, G3, G4, G5, G6 are defined between the portion of the second member grinding bars 36 and the second grinding bars 26B.

[0116] The method can continue by rotating at least one of the first grinding member 20 or the second grinding member 30 in step 510 so that the first grinding member 20 and the second grinding member 30 move relative to each other, and then, in step 520, supplying a wood pulp slurry containing wood fibers to the grinder 10 so that the slurry passes through the grinding space 60. In step 530, an axial pressure can be provided to at least one of the first grinding member 20 or the second grinding member 30 while supplying the slurry so that the gaps G2, G3, G4, G5, G6 between that part of the second member grinder bar 36 and the second grinder bar 26B are between about 0.9 mm and about 1.5 mm, wherein at least a part of the wood fiber bundles passing through the gaps G2, G3, G4, G5, G6 are separated, after which the method can terminate.

[0117] Although specific embodiments of the invention have been illustrated and described, it should be understood that various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, it is intended that all such changes and modifications falling within the scope of the invention be included in the appended claims.

Claims

1. A grinding member for a wood pulp grinder, the grinding member comprising: A grinding body including a grinding surface, the grinding surface comprising: First grinding machine bars separated by first grinding machine grooves, each first grinding machine bar extending from a radially inner position on the grinding surface to a first radially outer position on the grinding surface; Second grinding machine bars separated by second grinding machine grooves, each second grinding machine bar extending from a second radially inner position to a second radially outer position on the grinding surface, each of the second grinding machine bars having a longitudinal length of 0.6 cm to 10 cm, wherein the second radially outer position of each second grinding machine bar is closer to the outermost part of the grinding body than the corresponding first radially outer position of each first grinding machine bar, each of the first grinding machine bars having a first maximum height extending upward from the bottom of the adjacent first grinding machine groove, each of the second grinding machine bars having a second maximum height and a second minimum height extending upward from the bottom of the adjacent second grinding machine groove; Wherein the height of each second grinding machine bar decreases from the second maximum height to the second minimum height, and the second maximum height is closer to the second radially inner position than the second minimum height.

2. The lapping member according to claim 1, wherein, When measured from the bottom of the adjacent first grinding machine groove, the first maximum height of the first grinding machine bar is 4 mm to 10 mm.

3. The abrasive member according to claim 2, wherein, When measured from the bottom of the adjacent second grinding machine groove, the second maximum height of the second grinding machine bar is 0.35 mm to 1.5 mm smaller than the first maximum height.

4. The lapping member according to claim 2, wherein, When measured from the bottom of the adjacent second grinding machine groove, the second maximum height of the second grinding machine bar is 0.7 mm to 1.5 mm smaller than the first maximum height.

5. The lapping member according to claim 1, wherein, The longitudinal length of the second grinding machine bar is 2 cm to 10 cm.

6. The lapping member according to claim 1, wherein, The second grinding machine bars are integral with the first grinding machine bars such that the second grinding machine bars extend from the first radially outer position to the second radially outer position.

7. The abrasive member according to claim 6, wherein, Each second grinding machine bar continuously slopes downward from the first radially outer position to the second radially outer position.

8. The lapping member according to claim 1, wherein, The first and second grinding machine bars have a width extending between the side edges, the width being from 2 mm to 8 mm.

9. The lapping member according to claim 1, wherein, At least a part of the first grinding machine groove is provided with a dam.

10. The grinding member according to claim 1, further comprising: Third grinding machine bars separated by third grinding machine grooves, each third grinding machine bar extending to a third radially outer position on the grinding surface; Fourth grinding machine bars separated by fourth grinding machine grooves, each fourth grinding machine bar extending to a fourth radially outer position on the grinding surface, the fourth grinding machine bars having a longitudinal length of 0.6 cm to 10 cm, wherein the fourth radially outer position is closer to the outermost part of the grinding body than the third radially outer position, the third grinding machine bars having a third maximum height extending upward from the bottom of the adjacent third grinding machine groove, the fourth grinding machine bars having a fourth maximum height extending upward from the bottom of the adjacent fourth grinding machine groove, the fourth maximum height being at least 0.35 mm smaller than the third maximum height; Wherein the third grinding machine bars are adapted to grind wood fibers and the fourth grinding machine bars are adapted to break fiber bundles.

11. The lapping member according to claim 10, wherein, The third grinding bar is integral with the second grinding bar such that the third grinding bar extends from a second radially outer position to a third radially outer position, and the fourth grinding bar is integral with the third grinding bar such that the fourth grinding bar extends from the third radially outer position to a fourth radially outer position.

12. The lapping member according to claim 1, wherein, Each second grinding groove has a groove width of 2 mm to 6 mm.

13. The lapping member according to claim 1, wherein, The second radially outer position of each second grinding bar is closer to the outermost part of the grinding body than the first radially outer position of the corresponding one of the first grinding bars.

14. The lapping member according to claim 1, wherein, The height of each second grinding bar decreases continuously.

15. A wood pulp grinder, comprising: A frame; At least a first pair of grinding members, comprising: A first grinding member associated with the frame and including a first grinding body, the first grinding body including a first grinding surface, the first grinding surface including: First grinding bars separated by first grinding grooves, each first grinding bar extending from A radially inner position on the first grinding surface to a first radially outer position on the first grinding surface; and Second grinding bars, each second grinding bar extending from a second radially inner position to A second radially outer position on the first grinding surface, each of the second grinding bars having a longitudinal length from 0.6 cm to 10 cm, wherein the second radially outer position is closer to the outermost part of the grinding body than the first radially outer position of the corresponding one of the first grinding bars, each of the first grinding bars having a first maximum height extending upward from the bottom of the adjacent first groove, each of the second grinding bars having a second maximum height and a second minimum height extending upward from the bottom of the adjacent second grinding groove, the second maximum height being at least 0.35 mm less than the first maximum height, wherein the second maximum height is closer to the second radially inner position than the second minimum height; A second grinding member associated with the frame and including a second grinding body, the second grinding body including a second grinding surface, the second grinding surface including second member grinding bars separated by second member grinding grooves, the first grinding member being spaced apart from the second grinding member so as to define a grinding space therebetween; and A rotor associated with the frame and coupled to one of the first grinding member or the second grinding member such that rotation of the rotor causes relative movement between the first grinding member and the second grinding member.

16. The wood pulp grinder according to claim 15, wherein, Each second grinding groove has a groove width of 2 mm to 6 mm.

17. The wood pulp grinder according to claim 15, wherein, The second maximum height is 0.35 mm to 1.5 mm less than the first maximum height.

18. The wood pulp grinder according to claim 15, wherein, The second maximum height is at least 0.7 mm less than the first maximum height.

19. The wood pulp grinder according to claim 15, wherein, The longitudinal length of the second grinding bar is 2 cm to 10 cm.

20. The wood pulp grinder according to claim 15, wherein, The second member grinding bar includes: A third grinding bar extending from a radially inner position on the second grinding surface to a first radially outer position on the second grinding surface; A fourth grinding bar extends to a second radially outer position on the second grinding surface, where the second radially outer position is closer to the outermost part of the second grinding body than the first radially outer position. The third grinding bar has a third maximum height extending upward from the bottom of the adjacent groove, and the fourth grinding bar has a fourth maximum height extending upward from the bottom of the adjacent groove. The fourth maximum height is at least 0.35 mm smaller than the third maximum height.

21. The wood pulp grinder according to claim 15, wherein, The first grinding member is a non-rotating stator member, and the second grinding member is a rotating rotor member.

22. A grinding member for a wood pulp grinder, the grinding member comprising: A grinding body including a plurality of radially extending disc-shaped sections, the disc-shaped sections including: At least one first disc-shaped section including a first grinding surface, the first grinding surface including first grinding bars separated by first grinding grooves, the first grinding bars having a first maximum height extending upward from the bottom of the adjacent first grinding grooves; At least one second disc-shaped section including a second grinding surface, the second grinding surface including second grinding bars separated by second grinding grooves, each second grinding bar extending from a second radially inner position to a second radially outer position on the second grinding surface, each second grinding bar having a second maximum height and a second minimum height extending upward from the bottom of the adjacent second grinding grooves, the second maximum height being 0.35 mm to 1.5 mm smaller than the first maximum height, wherein the height of each second grinding bar continuously decreases from the second maximum height to the second minimum height, and wherein the second maximum height is closer to the second radially inner position than the second minimum height.

23. The lapping member according to claim 22, wherein, When measured from the bottom of the adjacent first grinding grooves, the first maximum height of the first grinding bars is 4 mm to 10 mm.

24. The lapping member according to claim 22, wherein, When measured from the bottom of the adjacent second grinding grooves, the second maximum height of the second grinding bars is 0.35 mm to 1.5 mm smaller than the first maximum height.

25. The lapping member according to claim 22, wherein, When measured from the bottom of the adjacent second grinding grooves, the second maximum height of the second grinding bars is 0.7 mm to 1.5 mm smaller than the first maximum height.

26. A method for processing wood fibers, comprising: Providing a single grinder including at least a first pair of grinding members, the first pair of grinding members including a first grinding member and a second grinding member spaced apart from each other to define a grinding space therebetween, the first grinding member including a first grinding body having a first grinding surface, the second grinding member including a second grinding body having a second grinding surface, wherein the first grinding surface includes first grinding bars separated by first grinding grooves and second grinding bars separated by second grinding grooves, the second grinding bars having a longitudinal length of 0.6 cm to 10 cm; Rotating at least one of the first grinding member or the second grinding member such that the first grinding member and the second grinding member move relative to each other; Supplying a wood pulp slurry including wood fibers to the single grinder such that the slurry passes through the grinding space; The wood fibers are ground in a grinding zone that is at least partially defined by a portion of a grinding chamber that is at least partially defined by a first grinder groove and extends from a radially inward position on a first grinding surface to a first radially outward position on the first grinding surface; and The wood fibers are defibrated in a defibration zone that is at least partially defined by a portion of a grinding chamber that is at least partially defined by a second grinder groove and extends from the first radially outward position on the first grinding surface to a second radially outward position on the first grinding surface; wherein: The defibrating and grinding occur within a single grinder.

27. The method according to claim 26, wherein The second radially outward position is closer to the outermost part of the first grinding body than the first radially outward position, such that the defibration of the wood fibers occurs at a radially outward position of the single grinder as compared to the grinding step.

28. The method according to claim 26, wherein, The second grinding surface includes second grinder bars separated by second member grinder grooves, and at least a portion of the second grinder bars is positioned opposite the second grinder bars, thereby defining a gap between the portion of the second grinder bars and the second grinder bars; When supplying the slurry, axial pressure is applied to at least one of the first grinding member or the second grinding member such that the gap between the portion of the second grinder bars and the second grinder bars is between 0.9 mm and 1.5 mm, wherein at least a portion of the wood fiber bundles passing through the gap are separated.

29. The method according to claim 26, wherein The first grinder bars have a first maximum height extending upward from the bottom of adjacent first grinder grooves, the second grinder bars have a second maximum height extending upward from the bottom of adjacent second grinder grooves, and the second maximum height is at least 0.35 mm less than the first maximum height.

30. The method according to claim 26, wherein, The longitudinal length of the second grinder bars is from 2 cm to 10 cm.

31. The method according to claim 26, wherein, The second member grinder bars include: Third grinder bars; and Fourth grinder bars, the third grinder bars have a third maximum height extending upward from the bottom of adjacent grooves, the fourth grinder bars have a fourth maximum height extending upward from the bottom of adjacent grooves, and the fourth maximum height is at least 0.35 mm less than the third maximum height.

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