Wood fiber micro-nano crushing device magnetically driven by uniform magnetic field gradient composite coil, control method and design method

Abstract

The invention discloses a wood fiber micro-nano crushing device magnetically driven by a uniform magnetic field gradient composite coil, a control method and a design method, the wood fiber micro-nano crushing device comprises a combined coil unit, and the combined coil unit is arranged on a motion track where a magnetic ball moves. The combined coil unit is formed by sequentially connecting leads of a conical coil, a circular coil and a square coil in series; the small end part of the conical coil faces the circular coil, and the wire winding directions of the conical coil and the circular coil are the same; the wire winding directions of the square coil, the conical coil and the circular coil are opposite. The magnetic field distribution of the combined coil is different from the concentrated distribution of the middle magnetic field of the traditional circular coil, so that the magnetic field intensities at different radial positions along the axial direction can be uniformly increased, the uniformity of the magnetic field gradient is ensured, and the magnetic balls at different positions are uniformly stressed; and the energy loss caused by collision among the particles is greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the field of wood fiber processing devices, and in particular relates to a wood fiber micro-nano crushing device driven by the magnetic force of a uniform magnetic field gradient composite coil in a magnetic acceleration device. Background Art

[0002] Wood fiber, primarily derived from wood, bamboo, and agricultural waste, is renewable and biodegradable, making it of great significance in the utilization of renewable resources and the development of green materials. However, wood fiber suffers from inherent surface activity and functional defects, resulting in poor interfacial compatibility, a single function, and slow degradation due to its dense structure.

[0003] Micro-nanoprocessing is a key technological path to overcoming these bottlenecks, enabling the transformation of wood resources from "inefficient utilization" to "high-value" utilization. Micro-nanoprocessed wood fibers possess a higher specific surface area and more uniform dispersion, significantly improving their performance in composite materials, such as enhancing mechanical strength, toughness, and impact resistance. Furthermore, their degradation rate is significantly accelerated, which is of great significance for the research and development and application of biodegradable composites in packaging, agriculture, and biomedicine, effectively reducing the use of traditional plastics and lowering environmental pollution. Furthermore, micro-nanoprocessing technology has opened up new application areas for wood fibers, beyond traditional composite materials, in high-tech fields such as electronics, energy, and biomedicine. For example, in electronics, they can be used to prepare high-performance insulating materials and flexible electronic devices; in energy, they can be used to prepare high-performance battery electrode materials and energy storage materials; and in biomedicine, they can be used to develop novel biodegradable medical devices and tissue engineering scaffolds. However, common micro-nanoprocessing methods, such as mechanical grinding, airflow milling, acid-base treatment, and TEMPO oxidation, suffer from high energy consumption, high pollution, low efficiency, and limited micro-nanoprocessing, hindering their large-scale application and development.

[0004] Patent application CN119502070A describes a circular magnetic pulverization system for micro- and nano-crushing of wood fibers. This system fills a circular pulverization cavity with conductive particles and incorporates multiple electromagnetic drive mechanisms. The system primarily relies on the magnetic field generated by a circular solenoid coil as its power source. However, this acceleration method has significant drawbacks: the magnetic field generated by the coil is unevenly distributed in the axial and radial directions, resulting in poor magnetic field uniformity. This causes uneven forces on the particles, leading to deviations from the preset trajectory and collisions. This results in some conductive particles losing kinetic energy before striking the wood fibers, resulting in energy loss and making it difficult to achieve the desired crushing effect. Furthermore, when accelerating multiple particles, the forces acting on the particles vary significantly, resulting in inconsistent passage times through the coil sensor, forcing the coil to be frequently powered on and off, increasing energy consumption. The circular solenoid coil used in this patent also suffers from limited controllability of the maximum magnetic field intensity, resulting in higher energy consumption when reaching maximum speed. In contrast, the novel coil design proposed in this patent produces a more uniform "magnetic particle cluster," enabling faster peak speeds and a higher maximum saturation speed, effectively addressing these energy consumption and efficiency issues. Summary of the Invention

[0005] This invention addresses existing issues with magnetically crushing wood fibers for micro- and nano-processing, overcoming energy consumption and efficiency issues caused by uneven force within existing circular coils. By thoroughly studying the magnetic field distribution of common coil types—circular, square, triangular, and conical—we propose a device and method for magnetically crushing wood fibers using a uniform magnetic field gradient composite coil.

[0006] In order to achieve the above purpose, the technical route adopted by the present invention is as follows:

[0007] In the first aspect, a micro-nano crushing device for wood fibers driven by magnetic force of a uniform magnetic field gradient composite coil comprises a combined coil unit, wherein the combined coil unit is arranged on a motion track of a magnetic ball, and the combined coil unit is composed of a conical coil, a circular coil, and a square coil whose conductors are connected in series in sequence, and the central axes of the conical coil, the circular coil, and the square coil are kept consistent; the small end portion of the conical coil faces the circular coil, and the winding direction of the conductors of the conical coil and the circular coil is the same; the winding direction of the conductors of the square coil is opposite to that of the conical coil and the circular coil.

[0008] The above-mentioned uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device is based on the principle of magnetic field superposition. The magnetic field distribution of this combined coil is different from the concentrated distribution of the intermediate magnetic field of the traditional circular coil. It can make the magnetic field intensity at different radial positions along the axial direction increase uniformly, ensuring the uniformity of the magnetic field gradient size, and then ensuring that the magnetic balls at different positions are subjected to uniform force, so that the energy loss caused by collisions between particles is greatly reduced.

[0009] As a further technical solution, a power module is provided in the space enclosed by the motion track, the conductors of the conical coil, circular coil and square coil are connected to the power module, and the power module is connected to the control module.

[0010] As a further technical solution, the wire winding direction of the conical coil and the circular coil is clockwise; the wire winding direction of the square coil is counterclockwise.

[0011] As a further technical solution, a sensor is installed on the outside of the square coil. When the magnetic ball passes through the sensor, the control module controls the power supply to be energized, thereby energizing the coil to generate a magnetic field.

[0012] As a further technical solution, a sensor is installed on the outside of the circular coil. When the magnetic ball passes through the sensor, the control module will control the power supply to be cut off, thereby cutting off the power to the coil and eliminating the magnetic field.

[0013] As a further technical solution, each combined coil is individually powered on and off by a control module to reduce energy consumption.

[0014] As a further technical solution, the combination coil unit includes multiple combination coil units, and the multiple combination coil units are evenly arranged along the circumferential direction of the motion track of the magnetic ball.

[0015] In a second aspect, the present invention also provides a control method for a wood fiber micro-nano crushing device driven by a uniform magnetic field gradient composite coil, as follows:

[0016] When the square coil of the first-stage combined coil unit detects the arrival of the magnetic ball, all coils of the first-stage combined coil unit are energized, and a magnetic field is generated inside the coil. The direction of the magnetic domain inside the ferromagnetic ball tends to be consistent with the direction of the coil magnetic field, generating a magnetic attraction. The direction of the attraction points from low magnetic field intensity to high magnetic field intensity, and the magnitude of the attraction is proportional to the magnetic field gradient.

[0017] When the magnetic ball passes through the outside of the circular coil, the power to the first-stage combined coil unit is cut off, the magnetic field disappears, and the magnetic ball continues to move to the next-stage combined coil unit by inertia; at this time, the working principle of the next-stage combined coil unit is the same as that of the previous one, and it continues to accelerate. Through the relay acceleration of multiple-stage combined coil units, the kinetic energy of the magnetic ball is gradually added, and finally reaches the saturation speed.

[0018] In a third aspect, the present invention further provides a design method for the uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device, as follows:

[0019] Step 1: Create a simple 3D model of the combined coil unit;

[0020] Step 2: Establish an air domain, where the range of the air domain is three times the length, width and height of the combined coil unit, covering the analysis area of the combined coil unit;

[0021] Step 3: Set the material properties of the combined coil unit and set the relative magnetic permeability to 1;

[0022] Step 4: Mesh the combined coil unit; use internal meshing and control the mesh based on length, setting the maximum side length of the control edge to no more than 0.5 mm;

[0023] Step 5: Apply an excitation current to the combined coil unit so that the direction of the current application is along the designed direction;

[0024] Step 6: Define the boundary conditions of the simulation analysis as the balloon boundary model;

[0025] Step 7: Perform simulation analysis, define the axial and radial paths of the combined coil unit, and obtain the magnetic field distribution on the axial and radial paths.

[0026] The beneficial technical effects of the present invention are:

[0027] 1. Based on the principle of magnetic field superposition, the magnetic field distribution of this combined coil is different from the concentrated distribution of the central magnetic field of a traditional circular coil. It can evenly increase the magnetic field intensity along the axis at different radial positions, ensuring the uniformity of the magnetic field gradient. This ensures that the magnetic balls at different positions are evenly stressed, significantly reducing the energy loss caused by collisions between particles.

[0028] 2. The unique magnetic field distribution of this combined coil realizes the synchronous acceleration of the "magnetic particle cluster". Specifically, the acceleration process of a single-stage coil is that when the magnetic ball approaches a certain level of combined coil unit through the motion track, the sensor outside the square coil detects the arrival signal of the ball, and the control module immediately energizes the coil of this level. The composite superimposed magnetic field generated realizes the radial synchronous acceleration of the magnetic particles from the low magnetic field area (coil entrance) to the high magnetic field area (coil center). When the ball moves to the outside of the circular coil, the sensor detects that the ball has left, triggering the control module to power off, the magnetic field disappears, and the ball relies on inertia to enter the acceleration area of the next level of combined coil unit, effectively solving the problem of inconsistent time for the ball to pass through the coil sensor due to uneven force of the traditional circular coil, thereby avoiding the disadvantages of too high frequency of coil power on and off and high energy consumption.

[0029] 3. This combined coil breaks through the limitations of traditional circular coil pulse acceleration. By optimizing the magnetic field distribution, it significantly extends the effective acceleration area path, significantly improving the saturation velocity of the magnetic balls, thereby greatly improving the micro-nano degree of wood fibers. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The magnetic field distribution vector diagram and magnetic field intensity cloud diagram of the circular coil; (a) the magnetic field distribution vector diagram of the circular coil; (b) the magnetic field intensity cloud diagram of the circular coil;

[0031] Figure 2 The magnetic field distribution vector diagram and magnetic field intensity cloud diagram of the square coil are shown in Figure 1. (a) The magnetic field distribution vector diagram of the square coil; (b) The magnetic field intensity cloud diagram of the square coil;

[0032] Figure 3 The magnetic field distribution vector diagram and magnetic field intensity cloud diagram of the triangular coil; (a) the magnetic field distribution vector diagram of the triangular coil; (b) the magnetic field intensity cloud diagram of the triangular coil;

[0033] Figure 4 The magnetic field distribution vector diagram and magnetic field intensity cloud diagram of the conical coil are shown in Figure 1. (a) The magnetic field distribution vector diagram of the conical coil; (b) The magnetic field intensity cloud diagram of the conical coil;

[0034] Figure 5 is the magnetic field distribution vector diagram and magnetic field intensity cloud diagram of the combined coil; where (a) the magnetic field distribution vector diagram of the combined coil and (b) the magnetic field intensity cloud diagram of the combined coil;

[0035] Figure 6 is the magnetic field intensity distribution along the axis at the radial position r = 0 mm;

[0036] Figure 7 is the magnetic field intensity distribution along the axis at the radial direction r = 2mm;

[0037] Figure 8 is the magnetic field intensity distribution along the axis at the radial direction r = 4mm;

[0038] Figure 9 is the magnetic field intensity distribution along the axis at the radial direction r = 6mm;

[0039] Figure 10 is the magnetic field intensity distribution along the axis at the radial direction r = 8mm;

[0040] Figure 11 It is the cloud diagram of the overall magnetic field intensity distribution at different axial positions;

[0041] Figure 12 Specific magnetic field distribution cloud diagrams at different axial positions; where (a) z = 25 mm (b) z = 22 mm (c) z = 19 mm (d) z = 16 mm (e) z = 13 mm (f) z = 10 mm;

[0042] Figure 13 It is the distribution cloud of magnetic field intensity after the acceleration region ends;

[0043] Figure 14 This is the overall structure diagram of the electromagnetic accelerator;

[0044] Figure 15 This is a top view of the electromagnetic accelerator;

[0045] Figure 16 This is the overall structure diagram of the combined coil;

[0046] Figure 17 It is the left view of the combined coil;

[0047] In the figure: 1 combined coil unit; 2 central control module; 3 bracket and base, 4 ring track; 5 power module; 11 conical coil; 12 circular coil; 13 square coil; 14 square coil sensor; 15 circular coil sensor; DETAILED DESCRIPTION

[0048] The present invention relates to a magnetic acceleration device for micro-nano crushing of wood fibers, the core of which lies in the design of a radially symmetrical composite coil structure.

[0049] The specific implementation of the device will be described in detail below;

[0050] This embodiment provides a micro-nano crushing device for wood fibers driven by a uniform magnetic field gradient composite coil. By deeply studying the magnetic field distribution of common coil forms, namely circular coils, square coils, triangular coils, and conical coils, a micro-nano crushing device for wood fibers driven by a uniform magnetic field gradient composite coil and a method are proposed. Specifically, the magnetic field strength of a circular coil is large and relatively uniform within the central area, but the magnetic field strength decreases outward, and the degree of decrease along the axis is inconsistent at different radial positions. The magnetic field gradient is uneven and the maximum magnetic field gradient is small, which limits the acceleration distance and maximum speed of the particles. Compared with the circular coil, the magnetic field distribution of the square coil is more uniform in the radial direction, but the magnetic field strength in the central area is too large and the gradient is small, resulting in a short effective acceleration distance and a limited maximum speed. The magnetic field strength of the triangular coil at different axial positions varies significantly, resulting in a large difference in the electromagnetic force and a large degree of uneven movement. The edge magnetic field strength of the conical coil is large, and the internal magnetic field distribution is relatively uniform. The particles are subjected to more uniform forces at different axial positions, but the magnetic field gradient is small, and the maximum saturation speed is limited.

[0051] Based on the above analysis, this embodiment utilizes the principle of magnetic field superposition to design a radially symmetric composite coil structure. This structure creates a uniform and controllable magnetic field gradient along the axis, significantly enhancing the magnetic field gradient and extending the acceleration distance. This ensures that the "magnetic particle clusters" have the same velocity, effectively reducing the dynamic energy consumption associated with traditional pulsed acceleration and significantly increasing the saturation velocity. Compared to traditional coils, the present invention achieves a higher saturation velocity, higher efficiency, and lower energy consumption under the same conditions. This effectively addresses the three major technical challenges of energy consumption control, particle synchronization, and micronization, providing a highly efficient electromagnetic acceleration solution for wood fiber micro-nano crushing. Specifically, the uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device comprises a combined coil unit, positioned on a trajectory of the magnetic ball. The combined coil unit comprises a series connection of wires from a conical coil, a circular coil, and a square coil. The small end of the conical coil faces the circular coil, and the wires of the conical and circular coils are wound in the same direction. The wires of the square coil are wound in the opposite direction to the conical and circular coils. This combined coil breaks through the limitations of traditional circular coil pulse acceleration. By optimizing the magnetic field distribution, it significantly extends the effective acceleration path, significantly increasing the saturation velocity of the magnetic spheres, and thus significantly improving the micronization of wood fibers. Based on the principle of magnetic field superposition, the magnetic field distribution of this combined coil differs from the concentrated intermediate magnetic field distribution of traditional circular coils. It can evenly increase the magnetic field intensity along the axis at different radial positions, ensuring the uniformity of the magnetic field gradient. This ensures that the magnetic spheres at different positions are evenly stressed, significantly reducing the energy loss caused by collisions between particles. The unique magnetic field distribution of this combined coil achieves synchronous acceleration of the "magnetic particle cluster", effectively solving the problem of inconsistent time for the spheres to pass through the coil sensor due to uneven force in traditional circular coils, thereby avoiding the disadvantages of excessively high coil power-on and power-off frequencies and high energy consumption.

[0052] Example 1

[0053] The uniform magnetic field gradient composite coil magnetic force driven wood fiber micro-nano crushing device proposed in this embodiment includes a combined coil unit 1, which is composed of a conical coil 11, a circular coil 12, and a square coil 13 connected in series in a specific order. Figure 16As shown. The small end of the conical coil 11 faces inward (that is, the small end of the conical coil faces the circular coil), and the large end faces outward, and the wire of the conical coil 11 is wound in a clockwise manner. The copper wire at the small end of the conical coil 11 is immediately connected in series with the circular coil 12, and the winding direction of the wire of the circular coil 12 remains clockwise. The copper wire on the outside of the circular coil 12 continues to be connected in series with the square coil 13, and the wire of the square coil is wound in a counterclockwise direction, and the central axes of the three coils remain consistent. Through this specific combination and winding method, the radial symmetry of the magnetic field and the uniform magnetic field gradient distribution are ensured. The magnetic field distribution of the combined coil can make the magnetic field intensity at different radial positions along the axial direction increase uniformly, ensure the uniformity of the magnetic field gradient, and then ensure that the magnetic balls at different positions are subjected to uniform force, so that the energy loss caused by collisions between the particles is greatly reduced.

[0054] Furthermore, the conductor may be an existing copper wire or other types of conductors.

[0055] Further, through Figure 16 It can be seen that four evenly spaced square coil sensors 14 are installed outside the square coil 13. When the magnetic ball arrives, the square coil sensor 14 receives a signal, triggering the control module to control the power module 5 to energize, causing the combined coil unit 1 to generate a magnetic field.

[0056] Furthermore, the circular coil 12 in this embodiment is also equipped with four evenly spaced circular coil sensors 15. Upon detecting the passage of a magnetic ball, the circular coil sensors 15 receive a signal, and the control module immediately controls the power module 5 to de-energize, eliminating the magnetic field and allowing the magnetic ball to continue forward by inertia. This design ensures that the magnetic ball receives sufficient acceleration as it passes through each coil, preventing the coil from exerting reverse pull on the ball and slowing it down. Furthermore, the control module's precise control of the coil's power on and off significantly reduces energy consumption.

[0057] The magnetic field distribution of a single coil in this embodiment is as follows Figure 1-Figure 4 , Figure 1 (a) Magnetic field distribution vector of circular coil 12; (b) Magnetic field intensity cloud diagram of circular coil 12; Figure 2 (a) Magnetic field distribution vector diagram of the square coil; (b) Magnetic field intensity cloud diagram of the square coil; Figure 3 (a) Magnetic field distribution vector diagram of the triangular coil; (b) Magnetic field intensity cloud diagram of the triangular coil; Figure 4(a) Magnetic field distribution vector diagram of a conical coil; (b) Magnetic field intensity cloud diagram of a conical coil; This embodiment superimposes and combines the magnetic field distribution characteristics of a single coil. The strong magnetic field at the edge of the conical coil 11 and the uniform distribution characteristics within the interior are combined with the radial magnetic field uniformity of the square coil. This compensates for the insufficient magnetic field gradient and radial magnetic field unevenness in the center of the circular coil 12, avoiding the magnetic field concentration and gradient unevenness problems of a single coil, thereby achieving a radially symmetric, large, uniform magnetic field gradient distribution.

[0058] In order to further study the magnetic field distribution of the combined coil unit 1, the magnetic field distribution obtained by optimizing the structural parameters of the combined coil unit 1 is shown in the following figure: Figure 5 As shown in the figure, the inner diameter structural parameter of the coil is set to r = 10 mm, the wall thickness of the motion track is removed, and the magnetic field intensity along the axis direction at different radial positions (r = 0 mm, 2 mm, 4 mm, 6 mm, 8 mm) is explored, as shown in the figure. Figures 6-10 As shown, the magnetic field strength increases uniformly from the outside of the square coil to the outside of the circular coil 12. The field calculator indicates that the magnetic field gradient at different radial positions has an error of no more than 5%. When the magnetic ball passes through the circular coil 12, the magnetic field strength begins to decrease. At this point, the power must be turned off to prevent a reverse pull.

[0059] Figure 12 The distribution of magnetic field strength along specific axial cross-sections is shown. Overall, the magnetic field strength exhibits a relatively uniform distribution across different axial cross-sections. Especially within the effective range of motion, the magnetic field strength remains essentially consistent, with minimal variation. This not only indicates a smaller magnetic field gradient but also reduces the radial force, significantly reducing the degree of interference with the magnetic ball's trajectory.

[0060] Figure 13 The magnetic field intensity distribution at the right end face of the conical coil 11 is presented. Figure 12 Compared to (f), the magnetic field intensity in this axial section shows a significant downward trend. If the coil remains energized when the magnetic ball passes this end face, a reverse pull will be generated, causing the ball's speed to decrease. Therefore, precisely controlling the timing of turning the coil on and off is extremely critical.

[0061] Figure 14 and Figure 15The schematic diagram of the overall structure of the electromagnetic accelerator shows a central control module 2, a combination coil unit 1, a bracket and base 3, and a circular track 4. The central control module 2 is located at the center of the device. Below it is the power module 5, which supplies power to the coils. Above it is the circuit control module, integrated with several electronic components (such as resistors, capacitors, diodes, and indicator lights) responsible for controlling the coils' on / off state and regulating current and voltage parameters. The four combination coil units 1 are evenly and symmetrically distributed around the central module to ensure uniform force distribution across the entire motion track of the magnetic ball. Each combination coil unit 1 is precisely secured by an independent bracket, ensuring a stable position. Each combination coil unit 1 is independently connected to the power module 5 for independent control, with two wires serving as lead-in and lead-out wires. A bracket for the circular track 4 is mounted on the circular base, effectively securing the track and preventing deviation caused by the high-speed motion of the ball. The base serves as the foundational support, supporting the central control module 2, coils, and bracket, providing structural stability for the entire device and ensuring the precise positioning of all components and overall stability during operation.

[0062] The acceleration process of the electromagnetic accelerator is divided into single-stage coil acceleration and multi-stage relay acceleration. The single-stage coil acceleration process is that when the magnetic ball approaches a certain stage of the combined coil unit 1 through the motion track, the sensor 14 outside the square coil detects the arrival signal of the ball, and the control module immediately energizes the coil of this stage. The clockwise winding direction of the conical coil 11 and the circular coil 12 generates a superimposed magnetic field, and the magnetic field gradient increases along the axis. The counterclockwise winding direction of the square coil 13 further adjusts the magnetic field distribution, so that the magnetic balls at different radial positions are subjected to uniform magnetic attraction, achieving synchronous acceleration, and accelerating from the low magnetic field area (coil entrance) to the high magnetic field area (coil center). The acceleration magnitude is: in, is the magnetic field gradient, M is the magnetization degree of the ball, and ρ is the density of the ball. When the ball moves to the outside of the circular coil 12, the circular coil sensor 15 detects that the ball has left, triggering the control module to cut off the power, and the magnetic field disappears. The ball relies on inertia to enter the acceleration area of the next-level combined coil unit 1. Since the direction of force on the ball is from the area with low magnetic flux distribution density to the area with high magnetic flux distribution density, when passing through the circular coil 12, the magnetic flux distribution density begins to gradually decrease. If the circular coil 12 is not powered off, the magnetic ball will be subjected to reverse pull, resulting in a back-pull phenomenon, which will reduce the ball's movement speed. Therefore, when the ball moves to the outside of the circular coil 12, the circular coil sensor 15 detects that the ball has left, triggering the control module to cut off the power.

[0063] Each stage of the combined coil units 1 operates on the same principle. Through relay acceleration, the kinetic energy of the magnetic spheres accumulates, eventually reaching saturation speed. The control module optimizes timing to synchronize the energizing intervals between adjacent coils with the sphere's motion, independently controlling the on / off switching of each combined coil unit 1. Furthermore, due to the uniform magnetic field gradients and high synchronization across each coil stage, multiple magnetic spheres can be accelerated simultaneously at different radial positions, avoiding the frequent on / off switching issues associated with uneven force distribution in conventional circular coils 12 and reducing energy consumption.

[0064] Example 2

[0065] This embodiment provides another uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device. The difference from Example 1 is that the wire winding direction of the conical coil 11 and the circular coil 12 in this embodiment is counterclockwise; the wire winding direction of the square coil is clockwise. The specific working principle and working process are basically the same as those in Example 1 and will not be repeated here.

[0066] Example 3

[0067] Based on Example 1 and Example 2, this embodiment further provides a design method for the uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device as follows:

[0068] Step 1: Create a simple 3D model of the combined coil unit 1 using Ansys Electronics Desktop.

[0069] Step 2: Create an air domain with a range of three times the length, width and height of the combined coil unit 1, covering the analysis area of the combined coil unit 1;

[0070] Step 3: Set the material properties of the combined coil unit 1, set the relative magnetic permeability to 1, and the material property to copper;

[0071] Step 4: Mesh the combined coil unit 1; use internal meshing and control the mesh based on length, setting the maximum side length of the control edge to no more than 0.5 mm;

[0072] Step 5: Apply an excitation current to the combined coil unit 1 so that the direction of the current application is along the designed direction;

[0073] Step 6: Define the boundary conditions of the simulation analysis as the balloon boundary model;

[0074] Step 7: Perform simulation analysis using Ansys Electronics Desktop software to define the axial and radial paths of the combined coil unit 1 and obtain the magnetic field distribution on the axial and radial paths.

[0075] The uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano-disintegration device designed in this embodiment achieves synchronous acceleration of the "magnetic particle clusters" through the unique magnetic field distribution of the combined coils. This effectively solves the problem of uneven force distribution in traditional circular coils, which leads to inconsistent passage of the balls through the coil sensor. This also avoids the drawback of excessive coil power-on and power-off frequency and high energy consumption. By achieving synchronous ball acceleration, the coil power-on and power-off frequency is significantly reduced, significantly reducing energy consumption.

[0076] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A micro-nano crushing device for wood fibers driven by magnetic force of a uniform magnetic field gradient composite coil, characterized in that: The invention comprises a combined coil unit, which is arranged on a motion track of a magnetic ball. The combined coil unit is composed of conductive wires of a conical coil, a circular coil, and a square coil connected in series in sequence, and the central axes of the conical coil, the circular coil, and the square coil are kept consistent; the small end of the conical coil faces the circular coil, and the conductive wires of the conical coil and the circular coil are wound in the same direction; the conductive wires of the square coil are wound in the opposite direction to those of the conical coil and the circular coil.

2. The uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device according to claim 1, characterized in that: A power module is provided in the space enclosed by the motion track. The wires of the conical coil, the circular coil and the square coil are connected to the power module, and the power module is connected to the control module.

3. The uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device according to claim 1, characterized in that: The wire winding direction of the conical coil and the circular coil is clockwise; the wire winding direction of the square coil is counterclockwise.

4. The uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device according to claim 1, characterized in that: A sensor is installed on the outside of the square coil. When the magnetic ball passes by the sensor, the control module will control the power supply to energize the coil, thereby energizing the coil to generate a magnetic field.

5. The uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device according to claim 1, characterized in that: A sensor is installed on the outside of the circular coil. When the magnetic ball passes through the sensor, the control module will control the power supply to be cut off, thereby cutting off the power to the coil and eliminating the magnetic field.

6. The uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device according to claim 1, characterized in that: Each combined coil is individually energized and de-energized by a control module to reduce energy consumption.

7. The uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device according to claim 1, characterized in that: The combination coil units include a plurality of combination coil units, and the plurality of combination coil units are evenly arranged along the circumferential direction of the motion track of the magnetic ball.

8. The control method of the uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device according to claim 1, characterized in that: When the square coil of the first-stage combined coil unit detects the arrival of the magnetic ball, all coils of the first-stage combined coil unit are energized, and a magnetic field is generated inside the coil. The direction of the magnetic domain inside the ferromagnetic ball tends to be consistent with the direction of the coil magnetic field, generating a magnetic attraction. The direction of the attraction points from low magnetic field intensity to high magnetic field intensity, and the magnitude of the attraction is proportional to the magnetic field gradient. When the magnetic ball passes through the outside of the circular coil, the power to the first-stage combined coil unit is cut off, the magnetic field disappears, and the magnetic ball continues to move to the next-stage combined coil unit by inertia; at this time, the working principle of the next-stage combined coil unit is the same as that of the previous one, and it continues to accelerate. Through the relay acceleration of multiple-stage combined coil units, the kinetic energy of the magnetic ball is gradually added, and finally reaches the saturation speed.

9. The design method of the uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device according to claim 1, characterized in that: as follows: Step 1: Create a three-dimensional model of the combined coil unit; Step 2: Create an air domain to cover the analysis area of the combined coil unit; Step 3: Set the material properties of the combined coil unit and set the relative magnetic permeability to 1; Step 4: Mesh the combined coil unit; use internal meshing and control the mesh based on length, setting the maximum side length of the control edge to no more than 0.5 mm; Step 5: Apply an excitation current to the combined coil unit so that the direction of the current application is along the designed direction; Step 6: Define the boundary conditions of the simulation analysis as the balloon boundary model; Step 7: Perform simulation analysis, define the axial and radial paths of the combined coil unit, and obtain the magnetic field distribution on the axial and radial paths.

10. The design method of the uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device according to claim 1, characterized in that: The range of the air domain is three times the length, width and height of the combined coil unit.

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