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

Abstract

This invention discloses a wood fiber micro / nano crushing device and its control and design methods driven by a composite coil with a uniform magnetic field gradient. The device includes a combined coil unit positioned on the motion track of a magnetic ball. The combined coil unit consists of a conical coil, a circular coil, and a square coil connected in series. 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 those of the conical and circular coils. The magnetic field distribution of this combined coil differs from the concentrated magnetic field distribution in the center of a traditional circular coil. It allows the magnetic field strength to increase uniformly along the axial direction at different radial positions, ensuring the uniformity of the magnetic field gradient. This, in turn, ensures that the magnetic ball at different positions experiences uniform force, significantly reducing energy loss from collisions between particles.

Description

Technical Field

[0001] This invention belongs to the field of wood fiber processing equipment, and particularly relates to a wood fiber micro-nano crushing device for magnetic drive of a uniform magnetic field gradient composite coil in a magnetic acceleration device. Background Technology

[0002] Wood fibers, primarily derived from timber, bamboo, and agricultural waste, possess renewable and biodegradable properties, making them significant for the utilization of renewable resources and the development of green materials. However, wood fibers exhibit inherent defects in surface activity and functionality, resulting in poor interfacial compatibility, limited functionality, and slow degradation due to their dense structure.

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

[0004] Patent application CN119502070A describes a ring-shaped magnetic crushing system for micro- and nano-scale crushing of wood fibers. This system fills a ring-shaped crushing cavity with conductive microparticles and incorporates multiple sets of electromagnetic drive devices, primarily relying on the magnetic force generated by an energized circular solenoid coil as its power source. However, this acceleration method has significant drawbacks: the magnetic field generated by the coil is unevenly distributed axially and radially, resulting in poor magnetic field uniformity. This leads to uneven force on the microparticles, causing them to deviate from their preset trajectories and collide with each other. Consequently, some conductive microparticles lose kinetic energy before even impacting the wood fibers, resulting in energy loss and hindering the achievement of ideal crushing effects. Furthermore, when accelerating multiple microspheres, the significant differences in force on the microparticles cause inconsistent passage times through the coil sensor, forcing frequent energization and de-energization of the coil, thus increasing energy consumption. The circular solenoid coil used in this patent also suffers from low controllability of the maximum magnetic field strength, leading to even higher energy consumption at maximum speed. In contrast, the novel coil design proposed in this patent can obtain a more uniform "magnetic microparticle cluster," achieving maximum speed faster and with a higher maximum saturation speed, effectively solving the aforementioned energy consumption and efficiency problems. Summary of the Invention

[0005] This invention addresses the problems existing in the magnetic crushing of wood fibers for micro-nano processing in current technologies, overcoming the energy consumption and efficiency issues caused by uneven force distribution within existing circular coils. Through in-depth research on the magnetic field distribution of common coil types—circular, square, triangular, and conical coils—a novel wood fiber micro-nano crushing device and method driven by a uniform magnetic field gradient composite coil is proposed.

[0006] To achieve the above objectives, the technical approach adopted by the present invention is as follows:

[0007] In the first aspect, a wood fiber micro / nano crushing device driven by a uniform magnetic field gradient composite coil includes a combined coil unit. The combined coil unit is set on the motion track of a magnetic ball. The combined coil unit consists of wires of a conical coil, a circular coil, and a square coil connected in series. The central axes of the conical coil, the circular coil, and the square coil are aligned. The small end of the conical coil faces the circular coil, and the wires of the conical coil and the circular coil are wound in the same direction. The wires of the square coil are wound in the opposite direction to those of the conical coil and the circular coil.

[0008] Based on the principle of magnetic field superposition, the above-mentioned uniform magnetic field gradient composite coil magnetically driven wood fiber micro-nano crushing device has a magnetic field distribution that is different from the central magnetic field distribution of traditional circular coils. It can make the magnetic field strength at different radial positions along the axial direction increase uniformly, ensuring the uniformity of the magnetic field gradient, thereby ensuring that the magnetic balls at different positions are subjected to uniform force, and greatly reducing the energy loss caused by collisions between particles.

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

[0010] As a further technical solution, the wires of the conical coil and the circular coil are wound clockwise; the wires of the square coil are wound counterclockwise.

[0011] As a further technical solution, a sensor is installed on the outside of the square coil. When the magnetic ball passes the sensor, the control module controls the power supply to turn on, thereby energizing the coil and generating 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 the sensor, the control module will control the power supply to cut off, thereby de-energizing the coil and eliminating the magnetic field.

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

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

[0015] Secondly, 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 the coils of the first-stage combined coil unit are energized, and a magnetic field is generated inside the coil. The direction of the magnetic domains inside the ferromagnetic ball tends to be consistent with the direction of the magnetic field of the coil, generating a magnetic attraction. The direction of the attraction is from the low magnetic field strength to the high magnetic field strength, and the magnitude of the attraction is proportional to the magnetic field gradient.

[0017] When the magnetic ball passes outside the circular coil, the first-stage combined coil unit is de-energized, the magnetic field disappears, and the magnetic ball continues to move to the next-stage combined coil unit due to inertia. At this time, the working principle of the next-stage combined coil unit is the same as that of the previous-stage combined coil unit, and it continues to accelerate. Through the relay acceleration of multiple combined coil units, the kinetic energy of the magnetic ball is successively added up, and finally reaches the saturation speed.

[0018] Thirdly, the present invention also provides a design method for the wood fiber micro / nano crushing device driven by the uniform magnetic field gradient composite coil, as follows:

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

[0020] Step 2: Establish an air domain, which is a region 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 permeability to 1;

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

[0023] Step 5: Apply excitation current to the combined coil unit, ensuring the direction of the current application is along the design direction;

[0024] Step 6: Define the boundary conditions for the simulation analysis as a 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 this invention are as follows:

[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 magnetic field in the middle of the traditional circular coil. It can make the magnetic field strength at different radial positions increase uniformly along the axial direction, ensuring the uniformity of the magnetic field gradient, thereby ensuring that the magnetic spheres at different positions are subjected to uniform force, and greatly reducing the energy loss caused by collisions between particles.

[0028] 2. The unique magnetic field distribution of this combined coil enables synchronous acceleration of "magnetic particle clusters." Specifically, the acceleration process of a single-stage coil is as follows: when a magnetic ball approaches a certain stage of the combined coil unit along its trajectory, the sensor on the outside of the square coil detects the arrival signal of the ball. The control module immediately powers on that stage of the coil, and the resulting superimposed magnetic field enables the magnetic particles to be radially and synchronously accelerated from the low magnetic field region (coil entrance) to the high magnetic field region (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 cut off the power. The magnetic field disappears, and the ball enters the acceleration region of the next stage of the combined coil unit by inertia. This effectively solves the problem of inconsistent ball passage time to the coil sensor due to uneven force distribution in traditional circular coils, and avoids the drawbacks of excessively high coil power-on and power-off frequencies 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, thereby significantly increasing the saturation velocity of the magnetic ball and greatly improving the micro-nanoization of wood fiber. Attached Figure Description

[0030] Figure 1 These are a vector diagram of the magnetic field distribution and a cloud map of the magnetic field intensity of a circular coil; where (a) is the vector diagram of the magnetic field distribution of the circular coil; and (b) is the cloud map of the magnetic field intensity of the circular coil.

[0031] Figure 2 These are a vector diagram of the magnetic field distribution of a square coil and a cloud map of the magnetic field intensity; where (a) is the vector diagram of the magnetic field distribution of the square coil; and (b) is the cloud map of the magnetic field intensity of the square coil.

[0032] Figure 3 These are a vector diagram of the magnetic field distribution of a triangular coil and a cloud map of the magnetic field intensity; where (a) is the vector diagram of the magnetic field distribution of the triangular coil; and (b) is the cloud map of the magnetic field intensity of the triangular coil.

[0033] Figure 4 These are the vector diagram of the magnetic field distribution and the cloud map of the magnetic field intensity of the conical coil; where (a) is the vector diagram of the magnetic field distribution of the conical coil; and (b) is the cloud map of the magnetic field intensity of the conical coil.

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

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

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

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

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

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

[0040] Figure 11 It is a cloud map showing the overall magnetic field intensity distribution at different positions along the axis;

[0041] Figure 12 These are specific magnetic field distribution cloud maps at different positions along the axis; where (a) z = 25 mm, (b) z = 22 mm, (c) z = 19 mm, (d) z = 16 mm, (e) z = 13 mm, and (f) z = 10 mm.

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

[0043] Figure 14 This is an overall structural diagram of the electromagnetic accelerator.

[0044] Figure 15 This is a top view of an electromagnetic accelerator.

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

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

[0047] In the diagram: 1 Combined coil unit; 2 Central control module; 3 Bracket and base; 4 Circular track; 5 Power module; 11 Conical coil; 12 Circular coil; 13 Square coil; 14 Square coil sensor; 15 Circular coil sensor; Detailed Implementation

[0048] This 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 this device will be described in detail below;

[0050] This embodiment provides a wood fiber micro / nano crushing device driven by a composite coil with a uniform magnetic field gradient. Through in-depth research on the magnetic field distribution of common coil types—circular, square, triangular, and conical coils—a method and device for wood fiber micro / nano crushing driven by a composite coil with a uniform magnetic field gradient are proposed. Specifically, circular coils have a relatively large and uniform magnetic field strength in the central region, but the magnetic field strength decreases outwards, and the degree of decrease is inconsistent along the axial direction at different radial positions, resulting in an uneven magnetic field gradient and a small maximum magnetic field gradient, which limits the particle acceleration distance and maximum speed. Square coils, compared to circular coils, have a more uniform magnetic field distribution in the radial direction, but the magnetic field strength in the central region is too large and the gradient is small, leading to a short effective acceleration distance and limited maximum speed. Triangular coils exhibit significant differences in magnetic field strength at different axial positions, resulting in large differences in the electromagnetic force experienced and a greater degree of motion non-uniformity. Conical coils have a large magnetic field strength at the edges and a relatively uniform internal magnetic field distribution, resulting in relatively uniform force on particles at different axial positions, but the small magnetic field gradient limits the maximum saturation velocity.

[0051] Based on the above analysis, this embodiment utilizes the principle of magnetic field superposition to design a radially symmetrical composite coil structure. This structure forms a uniform and controllable magnetic field gradient along the axial direction, significantly enhancing the magnetic field gradient and extending the acceleration distance, thereby enabling the "magnetic particle clusters" to have the same speed, effectively reducing the dynamic energy consumption generated by traditional pulse acceleration, and greatly improving the saturation speed. Compared with traditional coils, this invention achieves a higher saturation speed, higher efficiency, and lower energy consumption under the same conditions, effectively solving the three major technical challenges of energy consumption control, particle synchronization, and micro / nano-scale scaling, providing a highly efficient electromagnetic acceleration solution for wood fiber micro / nano-scale crushing. Specifically, the wood fiber micro / nano-scale crushing device driven by the magnetic force of the uniform magnetic field gradient composite coil includes a combined coil unit, which is set on the motion track of the magnetic ball. The combined coil unit consists of a conical coil, a circular coil, and a square coil connected in series with their wires. 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 those of the conical and circular coils. This combined coil overcomes the limitations of traditional circular coil pulse acceleration. By optimizing the magnetic field distribution, it significantly extends the effective acceleration area path, thereby significantly increasing the saturation velocity of the magnetic spheres and greatly improving the micro-nanoization of wood fibers. Based on the principle of magnetic field superposition, the magnetic field distribution of this combined coil differs from the concentrated magnetic field distribution in the center of traditional circular coils. It enables the magnetic field strength to increase uniformly along the axial direction at different radial positions, ensuring the uniformity of the magnetic field gradient. This, in turn, ensures that the magnetic spheres at different positions experience uniform force, significantly reducing energy loss caused by collisions between particles. The unique magnetic field distribution of this combined coil achieves synchronous acceleration of "magnetic particle clusters," effectively solving the problem of inconsistent sphere passage times through the coil sensor due to uneven force distribution in traditional circular coils. This also avoids the drawbacks of excessively high coil energization and de-energization frequencies and high energy consumption.

[0052] Example 1

[0053] The uniform magnetic field gradient composite coil magnetically driven wood fiber micro / nano crushing device proposed in this embodiment includes a combined coil unit 1. The combined coil unit 1 is composed of a conical coil 11, a circular coil 12, and a square coil 13 connected in a specific order, as detailed below. Figure 16As shown. The small end of the conical coil 11 faces inward (i.e., the small end of the conical coil faces the circular coil), and the large end faces outward. The wire of the conical coil 11 is wound clockwise. The copper wire at the small end of the conical coil 11 is connected in series with the circular coil 12, and the wire of the circular coil 12 is wound clockwise. The copper wire on the outside of the circular coil 12 continues to be connected in series with the square coil 13, while the wire of the square coil is wound counterclockwise. The central axes of the three coils are aligned. Through this specific combination and winding method, the radial symmetry and uniform magnetic field gradient distribution of the magnetic field are ensured. The magnetic field distribution of this combined coil can make the magnetic field strength increase uniformly along the axial direction at different radial positions, ensuring the uniformity of the magnetic field gradient. This, in turn, ensures that the magnetic spheres at different positions experience uniform force, significantly reducing the energy loss caused by collisions between particles.

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

[0055] Furthermore, through Figure 16 It can be seen that four evenly arranged square coil sensors 14 are installed on the outside of 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 turn on, so that the combined coil unit 1 generates a magnetic field.

[0056] Furthermore, in this embodiment, four evenly arranged circular coil sensors 15 are also installed on the outside of the circular coil 12. After detecting the magnetic ball passing through, the circular coil sensor 15 receives a signal, and the control module immediately controls the power module 5 to cut off the power. The magnetic field disappears, and the magnetic ball continues to move forward by inertia. This design ensures that the magnetic ball receives a sufficiently large acceleration when passing through each coil, avoiding the coil exerting a reverse pulling force on the ball and reducing its speed. In addition, by precisely controlling the energization and de-energization of the coils through the control module, energy consumption can be significantly reduced.

[0057] The magnetic field distribution of a single coil in this embodiment is as follows: Figures 1-4 , Figure 1 (a) Vector diagram of the magnetic field distribution of circular coil 12; (b) Contour diagram of the magnetic field intensity of circular coil 12; Figure 2 (a) Vector diagram of magnetic field distribution of a square coil; (b) Cloud map of magnetic field intensity of a square coil; Figure 3 (a) Vector diagram of magnetic field distribution of the triangular coil; (b) Contour diagram of magnetic field intensity of the triangular coil; Figure 4(a) Vector diagram of magnetic field distribution of conical coil; (b) Cloud map of magnetic field intensity of conical coil; In this embodiment, the magnetic field distribution characteristics of a single coil are superimposed and combined. The strong magnetic field at the edge of the conical coil 11 and the uniform distribution characteristics inside are combined with the radial magnetic field uniformity of the square coil to make up for the problem of insufficient magnetic field gradient in the central area of ​​the circular coil 12 and the problem of radial magnetic field non-uniformity. This avoids the problem of magnetic field concentration and gradient non-uniformity of a single coil, thereby achieving a radially symmetrical and larger uniform magnetic field gradient distribution.

[0058] To further investigate the magnetic field distribution of combined coil unit 1, the magnetic field distribution obtained by optimizing the structural parameters of combined coil unit 1 is as follows: Figure 5 As shown, the inner diameter of the coil is set to r = 10 mm. The wall thickness of the moving track is removed, and the magnetic field strength along the axial direction at different radial positions (r = 0 mm, 2 mm, 4 mm, 6 mm, 8 mm) is investigated. 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. According to the field calculator, the magnitude error of the magnetic field gradient at different radial positions does not exceed 5%. When the magnetic ball passes through the circular coil 12, the magnetic field strength begins to decrease. At this time, the power needs to be turned off, otherwise a reverse pulling force will be generated.

[0059] Figure 12 The distribution of magnetic field strength along a specific axial cross section is shown. Overall, the magnetic field strength exhibits a relatively uniform distribution across different axial cross sections, especially within the effective range of motion, where the magnetic field strength remains essentially constant with negligible differences. This not only implies a small magnetic field gradient but also weakens the radial force, thereby significantly reducing its interference with the trajectory of the magnetic ball.

[0060] Figure 13 The magnetic field strength distribution at the right end face of the conical coil 11 along its axial direction is shown. Figure 12 (f) In comparison, the magnetic field strength at this axial cross-section shows a significant decreasing trend. If the coil is still energized when the magnetic ball passes through this end face, a reverse pulling force will be generated, causing the ball's speed to decrease. Therefore, accurately controlling the timing of energizing and de-energizing the coil is extremely crucial.

[0061] Figure 14 and Figure 15This diagram illustrates the overall structure of the electromagnetic accelerator, including a central control module 2, combined coil units 1, a support and base 3, and a circular track 4. The central control module 2 is located at the center of the device. Below it is a power supply module 5, which supplies power to the coils. Above it is a circuit control module, integrating several electronic components (such as resistors, capacitors, diodes, and indicator lights) responsible for controlling the coil's on / off state and adjusting current and voltage parameters. Four combined coil units 1 are evenly and symmetrically distributed around the central module, ensuring uniform force on the magnetic ball throughout the motion track. Each combined coil unit 1 is precisely fixed by an independent support, ensuring stable positioning. Each combined coil unit 1 is individually connected to the power supply module 5 for independent control, with its two wires serving as the lead-in and lead-out wires, respectively. A circular track 4 support is mounted on the circular base to effectively fix the track and prevent track deviation caused by the high-speed movement of the ball. The base, as the fundamental support component, supports the central control module 2, coils, and support, providing a stable structural guarantee for the entire device and ensuring the positional accuracy and overall stability of each component during operation.

[0062] The acceleration process of the electromagnetic accelerator is divided into single-stage coil acceleration and multi-stage relay acceleration. In the single-stage coil acceleration process, when the magnetic ball approaches a certain stage of combined coil unit 1 along its trajectory, the sensor 14 on the outside of the square coil detects the ball's arrival signal. The control module immediately energizes that stage of coil. The clockwise winding direction of the conical coil 11 and the circular coil 12 generates a superimposed magnetic field, with the magnetic field gradient increasing along the axial direction. The counterclockwise winding direction of the square coil 13 further adjusts the magnetic field distribution, causing the magnetic balls at different radial positions to experience uniform magnetic attraction, achieving synchronous acceleration from the low magnetic field region (coil entrance) to the high magnetic field region (coil center). The magnitude of the acceleration is: in, Let M be the magnetic field gradient, M be the magnetization degree of the ball, and ρ be the ball density. 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. The magnetic field disappears, and the ball enters the acceleration region of the next stage combined coil unit 1 by inertia. Since the direction of the force on the ball is from the region of low magnetic field density to the region of high magnetic field density, the magnetic field density begins to gradually decrease when passing through the circular coil 12. If the circular coil 12 is not de-energized, the magnetic ball will be subjected to a reverse pull, resulting in a reverse pull phenomenon, which will reduce the speed of the ball. 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] The working principle of each stage of the combined coil unit 1 is the same. Through the relay acceleration of multiple stages of combined coil units 1, the kinetic energy of the magnetic ball is gradually added up until it reaches saturation speed. The control module is time-optimized to synchronize the energizing interval of adjacent coils with the movement of the ball, and independently controls the energizing of each combined coil unit 1. In addition, because the magnetic field gradient of each stage of the coil is uniform and highly synchronized, multiple magnetic balls can accelerate synchronously at different radial positions, avoiding the problem of frequent energizing and de-energizing caused by uneven force in traditional circular coils 12, thus reducing energy consumption.

[0064] Example 2

[0065] This embodiment provides another type of wood fiber micro / nano crushing device driven by a uniform magnetic field gradient composite coil. The difference from Embodiment 1 is that the winding direction of the wires of the conical coil 11 and the circular coil 12 in this embodiment is counterclockwise; the winding direction of the wires of the square coil is clockwise. The specific working principle and working process are basically the same as those in Embodiment 1, and will not be described in detail here.

[0066] Example 3

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

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

[0069] Step 2: Establish an air domain, which is a region 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 combined coil unit 1, set the relative permeability to 1, and the material property to copper;

[0071] Step 4: Perform meshing on the combined coil unit 1; use internal meshing and set the maximum edge length of the control edge to not exceed 0.5mm based on the length control mesh;

[0072] Step 5: Apply excitation current to the combined coil unit 1, ensuring that the direction of the applied current is along the design direction;

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

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

[0075] This embodiment utilizes a uniform magnetic field gradient composite coil magnetically driven wood fiber micro / nano crushing device. The unique magnetic field distribution of the combined coil enables synchronous acceleration of "magnetic particle clusters," effectively solving the problem of inconsistent ball passage times due to uneven force distribution in traditional circular coils. This avoids the drawbacks of excessively high coil energization and de-energization frequencies, resulting in high energy consumption. By achieving synchronous ball acceleration, the coil energization and de-energization frequency is significantly reduced, drastically lowering energy consumption.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A wood fiber micro / nano crushing device driven by a uniform magnetic field gradient composite coil, characterized in that, It includes a combined coil unit, which is set on the motion track of the magnetic ball; The combined coil unit is composed of a tapered coil, a circular coil, and a square coil connected in series with wires, and the central axes of the tapered coil, the circular coil, and the square coil are kept in the same direction. The small end of the conical coil faces the circular coil, and the wires of the conical coil and the circular coil are wound in the same direction; the wires of the square coil are wound in the opposite direction to those of the conical coil and the circular coil. A sensor is installed on the outside of the square coil to trigger the coil to be energized; A sensor is installed on the outside of the circular coil to trigger the coil to cut off power; The combined coil unit is configured such that, when energized, the magnetic field strength increases uniformly along the axial direction from the outside of the square coil to the outside of the circular coil, and the magnitude error of the magnetic field gradient at different radial positions does not exceed 5%, so as to achieve uniform force on the magnetic spheres at different radial positions and synchronous acceleration of the magnetic particle cluster.

2. The wood fiber micro / nano crushing device driven by a uniform magnetic field gradient composite coil as described in claim 1, characterized in that, A power module is installed within the space enclosed by the motion track. The wires of the conical coil, circular coil, and square coil are connected to the power module, which is in turn connected to the control module.

3. The wood fiber micro / nano crushing device driven by a uniform magnetic field gradient composite coil as described in claim 1, characterized in that, The wires of the conical and circular coils are wound clockwise; the wires of the square coil are wound counterclockwise.

4. The wood fiber micro / nano crushing device driven by a uniform magnetic field gradient composite coil as described in claim 1, characterized in that, Each combined coil is individually controlled by a control module to turn on and off, reducing energy consumption.

5. The wood fiber micro / nano crushing device driven by a uniform magnetic field gradient composite coil as described in claim 1, characterized in that, The combined coil unit comprises multiple units, which are evenly arranged along the circumferential direction of the magnetic ball's motion trajectory.

6. The control method for the wood fiber micro / nano crushing device driven by a uniform magnetic field gradient composite coil as described in claim 1, characterized in that, When the square coil of the first-stage combined coil unit detects the arrival of the magnetic ball, all the coils of the first-stage combined coil unit are energized, and a magnetic field is generated inside the coil. The direction of the magnetic domains inside the ferromagnetic ball tends to be consistent with the direction of the magnetic field of the coil, generating a magnetic attraction. The direction of the attraction is from the low magnetic field strength to the high magnetic field strength, and the magnitude of the attraction is proportional to the magnetic field gradient. When the magnetic ball passes outside the circular coil, the first-stage combined coil unit is de-energized, the magnetic field disappears, and the magnetic ball continues to move to the next-stage combined coil unit due to inertia. At this time, the working principle of the next-stage combined coil unit is the same as that of the previous-stage combined coil unit, and it continues to accelerate. Through the relay acceleration of multiple combined coil units, the kinetic energy of the magnetic ball is successively added up, and finally reaches the saturation speed.

7. The design method of the wood fiber micro / nano crushing device driven by a uniform magnetic field gradient composite coil as described in claim 1, characterized in that, as follows: Step 1: Establish a three-dimensional model of the combined coil unit; Step 2: Establish 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 permeability to 1; Step 4: Mesh the combined coil unit; use internal meshing and control the mesh based on length, setting the maximum edge length of the control edge to no more than 0.5mm; Step 5: Apply excitation current to the combined coil unit, ensuring the direction of the current application is along the design direction; Step 6: Define the boundary conditions for the simulation analysis as a 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.

8. The design method of the wood fiber micro / nano crushing device driven by a uniform magnetic field gradient composite coil as described in claim 7, characterized in that, The air domain is a region that is three times the length, width, and height of the combined coil unit.

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