High-density pulp beating method and plant for papermaking
The pulp refiner system with a perforated stator and high-speed rotor addresses high energy consumption and lack of precision in existing methods, achieving efficient and uniform pulp beating with reduced energy use and adaptable processes.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- ジャンネッリブルーノ
- Filing Date
- 2024-04-12
- Publication Date
- 2026-04-14
AI Technical Summary
Existing pulp beating methods, particularly using conical and disc refiners, require high energy consumption and do not allow for precise adjustments in fiber quality, especially when manufacturing different types of paper.
A pulp refiner system with a stator having perforated sidewalls and a rotor with blades that rotate at high speed, allowing the pulp to pass through perforations for beating, eliminating the need for additional pumps and enabling precise control over fiber beating through adjustable distance and speed settings.
Reduces energy consumption and enables precise fiber beating, achieving high-quality pulp with minimal pressure waves and uniformity, while allowing for different beating processes based on pulp type.
Smart Images
Figure 2026512088000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of papermaking, and more specifically, to a method for high-density pulp beating for papermaking.
[0002] The present invention further relates to a plant for implementing such a method.
[0003] In particular, the present invention relates to a pulp refiner used in such a method.
Background Art
[0004] As is well known, the pulp to be made into paper generally follows a so-called "concentrated pulp cycle" and then a "diluted pulp cycle" before reaching the machine head.
[0005] A typical concentrated pulp cycle involves pulping of suitable fiber materials in a pulper, final accumulation of the pulped pulp in a pulping pulp vat produced by the pulper, separation of any hard fragments and residual mud from the pulp in a centrifuge, a beating process in a pulp refiner, and passage into a generally beaten pulp collection vat.
[0006] As is also well known, the beaten pulp is sent to the diluted pulp cycle, which involves several vats and several passes of strong dilution with water, degassing, washing, and stabilization, and then is sent to the machine head.
[0007] Therefore, the beating of high-density pulp is an essential step in the papermaking cycle and is carried out by two main types of refiners, namely, a conical refiner and a disk refiner. Both apply impact shear force and pressure pulses to the pulp fiber material, separate the fibers entangled by the impact shear force into individual fibers as much as possible, and achieve fiber fibrillation by repeated pressure, thereby achieving the desired beating.
[0008] Typical truncated cone refiners are described in U.S. Patent No. 5,152,871, U.S. Patent No. 2016,355,977, U.S. Patent No. 2019,078,259, and European Patent No. 3839,134. These typically involve truncated cone rotors and stators having parallel grooves with sharp edges that extend along the generatrix of each cone face. The slurry moves axially in and out of the rotor and stator axes, traversing the entire gap, where it is subjected to both shear and high-frequency pressure stresses from the grooves of the stator and rotor in strong relative motion to each other.
[0009] A typical disc refiner, as described, for example, in U.S. Patent No. 5,467,931 or U.S. Patent No. 2019,203,417, comprises a pair of opposing discs, one fixed and the other rotating, separated by a gap. The discs have grooves on their surfaces with sharp edges. The pulp to be beaten is usually introduced into the gap through a central inlet, and as a result, the rapidly rotating grooves apply pressure pulses and impact shear forces to the pulp.
[0010] Both truncated cone refiners and disc refiners require a high-voltage supply to allow the pulp to advance along the gaps. Furthermore, the power required for the rotor increases to overcome the strong resistance between the truncated cone surfaces or the disc surfaces; therefore, a beating stage with this type of refiner requires several hundred kW of power in total.
[0011] Furthermore, existing refiners do not allow for precise changes in fiber quality even when the type of pulp and the type of paper being manufactured change. [Overview of the project]
[0012] The feature of the present invention is to provide a method for beating high-density pulp that can reduce energy absorption while maintaining at least the same beating quality.
[0013] Another feature of the present invention is to provide a method for beating high-density pulp that allows for precise modification of the degree of fiber beating and enables the achievement of a high Schöpper-Rigler beating grade.
[0014] A key feature of the present invention is the provision of a plant for beating high-density pulp, which achieves the above objective.
[0015] Next, a feature of the present invention is to provide a pulp refiner that achieves the above objective.
[0016] These purposes and other purposes are - A step of pre-positioning a stator having perforated side walls, - A step of pre-positioning a rotor rotatable within the stator, wherein the rotor comprises a plurality of blades, each having a cutting profile, positioned at a distance d from the perforation side wall, and the rotor is positioned to rotate relative to the stator at a peripheral speed v of the cutting profile (22), - A step of pre-arranging an inlet duct inside the stator and a collection chamber having an outlet duct outside the stator, - This is achieved by a method for beating high-density pulp, which includes the steps of supplying selected pulp previously separated from a solid portion to the stator through the inlet duct, wherein the blade (21) forces the selected pulp to pass between the cutting profile of the blade and the perforation sidewall, causing a beating action of the selected pulp, and supplying the beated fibers so that they pass through the perforation sidewall and reach the collection chamber and the outlet duct.
[0017] Advantageously, the stator has a circular opening, and the rotor comprises a rotating shaft having a disc flange, the disc flange being connected to the rotating shaft and rotatable within the circular opening, and a plurality of blades connected to the disc flange.
[0018] Therefore, the glazing passage of the blade cutting profile against the perforation sidewall detangles and cuts the selected pulp fibers in the section where the cutting profile is between one hole and the next in the perforation sidewall, and in the section where the cutting profile is in the hole of the perforation sidewall, the cut and detangled fibers are immediately passed through the perforation sidewall, achieving optimal fiber beating.
[0019] Compared to conventional technology, the absence of pressure waves simultaneously results in a dramatic reduction in required power and the achievement of extremely high peripheral speeds. In fact, the high-speed passage of the cutting profile glazing the perforation sidewalls leads to optimal beating, and the free passage of fibers through the perforation wall immediately afterward prevents the generation of pressure waves, thus avoiding strong braking forces on the rotor.
[0020] Advantageously, the distance d is set to 0.05mm to 0.5mm.
[0021] In particular, the peripheral speed v is set to 3000 rpm to 5000 rpm.
[0022] Advantageously, the blade is configured such that the rotation of the rotor draws selected pulp from the inlet duct and causes a flow of beaten pulp toward the collection chamber and the outlet duct.
[0023] In this way, the flow from the stator to the collection chamber is induced solely by the blades, avoiding excessive or negative pressure that could cause defects or inhomogeneity in the beating process. Furthermore, energy is saved by eliminating the need for a dedicated pump to induce the pulp flow through the stator.
[0024] In particular, these multiple blades protrude forward from the disc flange.
[0025] Advantageously, the blade protruding from the disk flange is configured to generate suction of the selected pulp from the inlet duct and cause a flow of beaten pulp towards the collection chamber and the outlet duct.
[0026] In this way, the disk flange closes the opening with minimum resistance to rotation, so that the blade can achieve a high rotational speed within the stator and handle a high pulp flow rate with the same power.
[0027] In particular, the inlet duct is arranged at an axial position on the opposite side of the rotor with respect to the stator.
[0028] Thus, the selected pulp contacts the blades of the rotor by axial movement, and the pulp immediately undergoes a radial movement towards the perforated side wall, is beaten, remains minimal within the stator, and quickly exits through the perforated side wall.
[0029] Advantageously, the perforated side wall of the stator has a cylindrical shape, and the cutting profile of the blade is configured to describe a cylindrical-shaped orbit that grazes the perforated side wall during rotation of the blade.
[0030] Advantageously, the perforated side wall of the stator has a frustum of a cone shape, and the cutting profile of the blade is configured to describe a frustum-of-a-cone-shaped orbit that grazes the perforated side wall during rotation of the blade. Adjusting means are also provided for changing the axial distance between the stator and the rotor so that the distance d can be changed.
[0031] Thus, by translating the rotor axially with respect to the stator, the distance d can be changed to adjust the degree of beating of the fibers.
[0032] In particular, the stator is detachably attached to a stand, and a plurality of stators with different holes drilled in their side walls are provided.
[0033] In this way, different beating processes can be performed depending on the type of pulp selected.
[0034] According to a further aspect of the present invention, a plant for beating high-density pulp is claimed, and this plant is - An inlet for introducing the pulp into the plant, - A stator having a perforated side wall and an axial opening communicating with the entrance, - A rotor rotatable within the stator, the rotor comprising a plurality of blades, each having a cutting profile positioned at a distance d from the perforated side wall, the rotor being positioned to rotate relative to the stator at a peripheral speed v of the cutting profile, - Includes a collection chamber located outside the stator and having an outlet duct configured to discharge the pulp beaten from the plant.
[0035] Advantageously, the stator has a circular opening, and the rotor comprises a rotating shaft having a disc flange, the disc flange being connected to the rotating shaft and rotatable within the circular opening, and a plurality of blades connected to the disc flange. [Brief explanation of the drawing]
[0036] Herein, the present invention is presented with reference to the accompanying drawings and together with the following description of some exemplary embodiments, which are illustrative but not limiting. [Figure 1] The selected pulp beating stages according to the present invention are shown. [Figure 2A] Possible embodiments of the rotor used in the method according to the present invention are shown in perspective views. [Figure 2B] Figure 2A shows a plan view of an embodiment of the rotor. [Figure 3] Possible exemplary embodiments of a stator and rotor used in the method according to the present invention are shown. [Figure 3A]Figure 3 shows a detail highlighting the distance between the rotor blade and the perforated sidewall of the stator. [Figure 4A] Further possible exemplary embodiments of a stator used in the method according to the present invention are shown. [Figure 4B] Further possible exemplary embodiments of a stator used in the method according to the present invention are shown. [Figure 4C] Further possible exemplary embodiments of a stator used in the method according to the present invention are shown. [Figure 4D] Further possible exemplary embodiments of a stator used in the method according to the present invention are shown. [Figure 5] A cross-sectional view shows a possible mechanical realization of a refiner used in a beating plant according to the present invention, where the stator has a frustoconical wall. [Modes for carrying out the invention]
[0037] Referring to the above figures, the method for beating high-density pulp according to the present invention involves the pre-arrangement of a stator 10 having perforated sidewalls 11, that is, having a number of holes 12 penetrating therein. The stator 10 and its holes 12 on the sidewalls 11 can be made in various shapes, as illustrated and non-limitingly shown in Figures 4A to 4D.
[0038] According to the method, a rotor 20 configured to rotatably engage within a stator 10 is then positioned. The rotor 20 includes a plurality of blades 21 having cutting profiles 22. Referring to Figure 3, the blades 21 are positioned such that their respective cutting profiles 22 trace a surface located at a distance d from the side wall 11, radially with respect to it, as the rotor 20's shaft 25 rotates ω around the x-axis common to the stator 10. Specifically, this distance d is 0.05 mm to 0.5 mm.
[0039] The rotor 20 rotates relative to the stator 10 such that the cutting profile 22 achieves a peripheral speed v relative to the side wall 11. In particular, such a peripheral speed v is between 3000 rpm and 5000 rpm.
[0040] An inlet duct 15 is provided inside the stator 10, and a collection chamber 30 with an outlet duct 31 is located outside the stator 10.
[0041] According to the method, the selected pulp 40, i.e., pulped pulp previously separated from the solid portion by, for example, a centrifuge, according to well-known techniques, is then supplied into the stator 10 through the inlet duct 15.
[0042] The rotation of the rotor 20 within the stator 10 causes the blade 21 to force the selected pulp 40 between the cutting profile 22 and the perforation sidewall 11, causing the beaten fibers to pass through the holes 12 in the perforation sidewall 11 and reach the collection chamber 30 and outlet duct 31.
[0043] In particular, the glazing passage of the cutting profile 22 of the blade 21 against the perforation sidewall 11 simultaneously untangles the fibers of the selected pulp 40 in the section where the cutting profile 22 is located between one hole 12 and the next hole 12 of the perforation sidewall 11, cuts the fibers by the dynamic cutting action of the cutting profile 22, and in the section where the profile cutting edge 22 is located corresponding to the holes 12 of the perforation sidewall 11, the cut and untangled fibers are immediately passed through the holes 12 of the perforation sidewall 11, thereby obtaining optimal beating of the fibers. In this way, the radial flow 41 of the beated fibers emerges from the holes 12 and is directed into the collection chamber 30, then forming a flow of beated pulp 42.
[0044] Advantageously, the blade 21 is configured such that the rotation ω of the rotor 20 causes the suction of selected pulp from the inlet duct 15 and the delivery of the beaten pulp toward the collection chamber 30 and the delivery duct outlet 31. For example, the blade 21 may have a curved or helical surface so that the rotation ω of the rotor 20 pushes the pulp radially, advancing it into the outlet duct 31 and generating suction from the inlet 15.
[0045] In this way, the fiber flow 41 from the stator 20 to the collection chamber 30 is caused solely by the blades 21, avoiding excessive or negative pressure that could cause defects or non-uniformity in the beating process. Furthermore, energy is saved by eliminating the need for a special pump to move the pulp through the stator.
[0046] In particular, referring to Figure 2B, in a possible embodiment, the blade 21 has a longitudinal axis positioned at a distance δ from the radial axis passing through the center O of the rotor 20. Furthermore, the blade 21 has a cutting profile 22 that forms a circumferential arc with center O and radius r1.
[0047] Thanks to the distance δ, when the rotor performs rotation ω in the direction shown in the figure, the profile 22 generates an attractive action that carries the fibers toward the perforation wall 11 of the stator 10, and therefore toward the outside of the stator itself, reducing the overall energy required for this operation compared to a configuration where the distance δ is zero.
[0048] In a possible embodiment shown in the figure, the stator has a circular opening 13, and the rotor 20 includes a rotating shaft 25 having a disc flange 23, the disc flange 23 being fixed to the shaft 25 and rotatable within the circular opening 13, with a plurality of blades 21 protruding forward from the disc flange 23. In particular, the disc flange 23 closing the opening 13 provides minimal resistance to rotation, allowing the rotor 20 and therefore the blades 21 to reach high rotational speeds within the stator and process high flow rates of pulp with the same power.
[0049] Even in this case, the blade 21 protruding from the disc flange 23 may have a curved profile configured to provide suction of selected pulp 40 from the inlet duct 15 and cause delivery of the beaten pulp 41 toward the collection chamber 30 and the outlet duct 31.
[0050] In the illustrated solution, the stator 10 has an inlet duct 15 in an axial position, i.e., on the x-axis opposite to the rotor 20. In this way, the selected pulp 40 comes into contact with the blades 21 of the rotor 20 by axial motion, and the blades 21 immediately impart a radial motion to the pulp toward the perforation sidewalls 11, forcing the pulp through the cutting profiles 22 and beating it, and then the beating fibers 41 are quickly expelled through the perforation sidewalls, leaving minimal residue inside the stator 10. Thus, the motion of the blades 21 is sufficient to suck, beat, and deliver the pulp, eliminating the need for further pumping.
[0051] In a possible embodiment as shown in the figure, the stator 10 has cylindrical sidewalls 11, and the cutting profiles 22 of the blades 21 are configured to trace cylindrical trajectories that glaze against the cylindrical sidewalls 11 during their rotation ω.
[0052] In possible embodiments, the stator 10 may have frustoconical sidewalls, and the cutting profiles 22 of the rotor blades 20 are configured to trace frustoconical trajectories glazing against the frustoconical sidewalls 11 during their rotation ω, and adjustment means are provided for recording the relative axial displacement between the stator and the rotor. In this way, it is possible to record the gap in the glazing trajectory of the cutting profiles against the frustoconical sidewalls, i.e., the aforementioned distance d, in order to adjust the degree of fiber beating.
[0053] As is well known, the degree of pulp beating is actually determined by the so-called "shear rate." In this case, the shear rate is directly proportional to the distance d and inversely proportional to the peripheral velocity v. Therefore, by decreasing the distance d, it is possible to increase the shear rate, and thus the degree of pulp beating.
[0054] In possible embodiments, the stator 10 is provided as a plurality of stators 10, each having perforated sidewalls 11 with different holes 12, and detachably mounted to a support. In this way, different beating methods are possible depending on the selected pulp type.
Claims
1. A method for beating high-density pulp, - A step of pre-positioning a stator (10) having a perforated side wall (11), - A step of pre-positioning a rotor (20) that can rotate within the stator (10), wherein the rotor (20) comprises a plurality of blades (21) each having a cutting profile (22) positioned at a distance d from the perforation side wall (11), and the rotor is positioned to rotate relative to the stator (10) at a peripheral speed v of the cutting profile (22), - A step of pre-arranging an inlet duct (15) inside the stator (10) and a collection chamber (30) having an outlet duct (31) outside the stator (10), - A step of supplying selected pulp previously separated from the solid portion to the stator (10) through the inlet duct (15), wherein the blade (21) forces the selected pulp to pass between the cutting profile (22) of the blade (21) and the perforating sidewall (11), causing a beating action of the selected pulp, and supplying the beated fibers to pass through the perforating sidewall (11) and reach the collection chamber (30) and the outlet duct (31), The method is characterized in that the stator (10) has a circular opening (13), and the rotor (20) is a rotating shaft (25) having a disc flange (23), wherein the disc flange (23) is connected to the rotating shaft (25) and is rotatable within the circular opening (13), and a plurality of blades (21) connected to the disc flange (23) at their front surfaces.
2. The beating method according to claim 1, wherein the distance d is set to 0.05 mm to 0.5 mm.
3. The beating method according to claim 1, wherein the peripheral speed v is set to 3000 rpm to 5000 rpm.
4. The beating method according to claim 1, wherein the blade (21) is configured to draw selected pulp from the inlet duct (15) by the rotation of the rotor (20) and cause a flow of beaten pulp toward the collection chamber (30) and the outlet duct (31).
5. The beating method according to claim 1, wherein the plurality of blades (21) protrude forward from the disc flange (23).
6. The beating method according to claim 5, wherein the blade (21) protruding from the disc flange (23) is configured to generate suction of selected pulp from the inlet duct (15) and cause a flow of beaten pulp toward the collection chamber (30) and the outlet duct (31).
7. The beating method according to claim 1, wherein the inlet duct (15) is positioned in an axial position opposite to the rotor (20) with respect to the stator (10).
8. The beating method according to claim 1, wherein the perforating side wall (11) of the stator (10) has a cylindrical shape, and the cutting profile (22) of the blade (21) is configured to trace a cylindrical trajectory that glazes the perforating side wall (11) during the rotation of the blade (21).
9. The beating method according to claim 1, wherein the perforating side wall (11) of the stator (10) has a frustoconical shape, and the cutting profile (22) of the blade (21) is configured to trace a frustoconical trajectory that glazes onto the perforating side wall (11) during rotation of the blade (21), and adjustment means are also provided for changing the axial distance between the stator (10) and the rotor (20) so that the distance d can be changed.
10. A plant (100) for beating high-density pulp, - An inlet (15) for introducing the pulp into the plant (100), - A stator (10) having a perforated side wall (11) and an axial opening (13) communicating with the inlet (15), - A rotor (20) rotatable within the stator (10), the rotor (20) comprising a plurality of blades (21) each having a cutting profile (22) positioned at a distance d from the perforation side wall (11), the rotor (20) being positioned to rotate relative to the stator (10) at a peripheral speed v of the cutting profile (22), - A collection chamber (30) located outside the stator (10) and having an outlet duct (31) configured to discharge the pulp beaten from the plant (100), The plant (100) is characterized in that the stator (10) has a circular opening (13), and the rotor 20 is a rotating shaft (25) having a disc flange (23), the disc flange (23) being connected to the rotating shaft (25) and rotatable within the circular opening (13), and a plurality of blades (21) connected to the disc flange (23).