Plasma food sterilization device

Abstract

The present application relates to the technical fields of plasma application, in particular to a kind of plasma grain disinfecting device based on surface discharge.The present application includes conveyor belt system, high voltage electrode, ground electrode, nanosecond pulse power module, electric control unit and safety protection structure.The surface of conveyor belt is provided with high voltage electrode and ground electrode which are staggered and embedded in the same plane, forming micro-slope electrode structure;Surface discharge plasma and slip wind are generated under high voltage excitation, and the thrust of ion wind is used to cooperate with electrode layout, so that the seeds in the conveying process automatically roll over, realizing multi-angle, all-round plasma exposure and disinfecting treatment.The present application solves the problems of uneven treatment, low efficiency, thermal damage or chemical residue in the prior art, and has the advantages of uniform treatment, green environmental protection, simplified structure, strong adaptability, etc., and is especially suitable for continuous online sterilization and preservation of grain seeds.

Description

Technical Field

[0001] This invention relates to the field of plasma application technology, specifically to a plasma grain sterilization device based on surface discharge, and more particularly to a device suitable for continuous grain conveying, which generates plasma on the surface of the conveyor belt to achieve sterilization and preservation. Background Technology

[0002] Grains are highly susceptible to contamination by microorganisms such as bacteria, molds, and fungi during harvesting, transportation, storage, and processing, leading to spoilage, fermentation, and even the production of harmful toxins. This not only reduces grain quality and shelf life but also poses a potential threat to food safety. Traditional grain disinfection and preservation technologies typically rely on high temperatures, ozone, chemical fumigants, or irradiation. These methods generally suffer from problems such as long processing times, high costs, potential damage to grain quality, or potential toxic side effects on humans, making it difficult to meet the demands for green, safe, and efficient processing.

[0003] In recent years, low-temperature plasma technology has shown broad application prospects in fields such as microbial inactivation and food preservation due to its suitable temperature, additive-free nature, and environmental friendliness. In particular, the non-thermal plasma generated by surface discharge can efficiently produce active particles (such as OH, O3, NOx, etc.) under atmospheric pressure, which have a significant bactericidal effect, while causing no thermal damage to the grain surface, making it extremely suitable for the rapid treatment of surface contamination.

[0004] Current plasma processing equipment primarily relies on static processing, where grains or seeds are fixed within a reaction chamber between electrodes. This method suffers from low processing efficiency, poor plasma uniformity, and a tendency to cause localized over- or under-processing. To improve processing efficiency and consistency, one approach is to incorporate a conveyor belt structure for "online" processing. However, traditional conveyor belt plasma designs often employ planar electrode structures, resulting in limited plasma distribution along the surface. Furthermore, the lack of effective turning of the grain during transport means that some grain surfaces are not fully exposed to the plasma environment, thus affecting the overall sterilization or preservation effect. Summary of the Invention

[0005] This invention addresses the problems of low uniformity in grain sterilization, low plasma utilization efficiency, complex structure, short lifespan, and limited seed treatment functions in existing grain sterilization devices. It proposes a plasma grain sterilization device comprising a conveyor belt mechanism, a nanosecond pulse power supply module, an electrical control unit, and a safety protection structure. The conveyor belt mechanism includes a conveyor belt and a transmission assembly; the conveyor belt is connected to a drive motor via the transmission assembly; a flexible insulating substrate is provided on the surface of the conveyor belt, on which staggered high-voltage electrodes and grounding electrodes are arranged; the bottoms of the high-voltage electrodes and grounding electrodes are coplanarly embedded in the flexible insulating substrate, and their surfaces are insulated to form a periodic micro-slope electrode structure; the safety protection structure is located on both sides of the conveyor belt. The high-voltage electrode is connected to the nanosecond pulse power supply module to excite surface discharge and generate plasma slip wind; The grounding electrode is connected to the electronic control unit and forms a coplanar discharge circuit with the high-voltage electrode. The electronic control unit includes a processing module, a transmission speed control module, a voltage waveform adjustment module, and a humidity monitoring module. The transmission speed control module, voltage waveform adjustment module, and humidity monitoring module are electrically connected to the processing module, respectively, and are used to coordinate the control of plasma generation and seed tumbling behavior. The electronic control unit is electrically connected to the nanosecond pulse power supply module and the conveyor belt mechanism.

[0006] According to the plasma grain sterilization device described above, the nanosecond pulse power supply module includes: a charging port, a DC battery, a boost module, a PWM pulse generator, an IGBT switch and a high-frequency transformer, an equivalent grounding terminal, and an equivalent load for the reactor; The DC battery is connected in parallel with the charging port; the boost module is electrically connected to the DC battery, the PWM pulse generator, and the high-frequency transformer respectively; the PWM pulse generator is electrically connected to the IGBT switch; the IGBT switch is electrically connected to the high-frequency transformer; the high-frequency transformer is electrically connected to the equivalent load of the reactor; and the high-frequency transformer is electrically connected to the equivalent ground terminal.

[0007] According to the plasma grain sterilization device described above, the transmission belt of the conveyor belt mechanism runs at a speed of 0.2–0.4 m / min, enabling the seeds to achieve self-driven tumbling and multi-faceted treatment under the action of plasma.

[0008] According to the plasma grain sterilization device described above, the width of the high-voltage electrode and the grounding electrode is 0.3-0.5 mm, the spacing is 0.4-0.6 mm, and the height is 0.1-1 mm. The materials of the high-voltage electrode and the grounding electrode are silver paste or copper foil, and the materials of the flexible insulating substrate are polyimide, PET, or PTFE flexible insulating materials.

[0009] According to the plasma grain sterilization device described above, the peak output voltage of the nanosecond pulse power supply module is 10-40 kV, the frequency is 1-10 kHz, and the duty cycle is 1%-90%.

[0010] According to the plasma grain sterilization device described above, the safety protection structure on both sides of the conveyor belt is a slight edge-blocking structure, which is used to limit the thickness of the grain spreading material to between 5-20 mm to avoid stacking and obstruction.

[0011] According to the plasma grain sterilization device described above, the electronic control unit also includes an atmosphere conditioning module connected to the processor module, which can be connected to oxygen or nitrogen auxiliary gas to adjust the composition of plasma active species.

[0012] According to the plasma grain sterilization device described above, a degradation zone is provided behind the conveyor belt mechanism, equipped with an exhaust module and an exhaust gas adsorption module for treating residual ozone and NOx.

[0013] According to the plasma grain sterilization device described above, the high-voltage electrode and the grounding electrode are arranged in an alternating high-voltage-grounding-high-voltage configuration to form a continuous and uniform surface discharge unit with a discharge gap of 3-6 mm.

[0014] According to the plasma grain sterilization device described above, the electronic control unit also includes an infrared detection module connected to the processor module, which is used to monitor the seed temperature and treatment effect in real time, and the data is fed back to the electronic control unit for adaptive parameter adjustment; the electronic control unit also includes a position sensor and an emergency stop button connected to the processor module respectively, which can automatically cut off the high voltage power supply and the transmission module when triggered.

[0015] The beneficial effects of this invention are as follows: 1. Improved processing uniformity and sterilization effect. This invention utilizes a periodic micro-slope electrode structure with a certain height and staggered distribution, combined with the synergistic drive of a plasma sliding wind field, to cause multidimensional tumbling and rotation of seeds during transport. This effectively breaks the limitation of "single-sided exposure" in traditional linear transport, achieving full-angle and multi-frequency plasma action on the seed surface, and significantly improving processing uniformity and reliability.

[0016] 2. Improved plasma utilization efficiency and processing depth. Compared with traditional static or planar plasma processing methods, this invention guides seeds to continuously update the exposed surface area in motion, avoiding the waste of space for plasma active species, improving the dynamic utilization rate of the reaction interface, and significantly enhancing the effective reaction density and physical interaction depth of the plasma.

[0017] 3. Achieving non-contact self-driven seed tumbling simplifies equipment structure. This invention utilizes plasma sliding wind generated by surface discharge as the active driving force, achieving self-driven rolling and tumbling of seeds without mechanical vibration or additional material turning structures. This non-contact power mechanism significantly simplifies the device structure, reduces wearing parts, and improves operational stability and system lifespan.

[0018] 4. Flexible structural design and strong adaptability. The staggered electrode design of this invention can be modularly customized, suitable for grains and seeds of different sizes and morphologies (such as beans, cereals, oilseeds, etc.), and can be expanded into a bipolar structure or a multi-channel structure to meet the needs of large-scale continuous processing scenarios. It has good engineering portability and scalability potential.

[0019] 5. Green and environmentally friendly with low risk of non-thermal damage. The atmospheric pressure pulsed plasma used in this invention is a low-temperature non-thermal treatment technology that poses no significant risk of thermal damage to seed structure and active ingredients. Furthermore, the entire treatment process does not rely on chemical reagents or fungicides, leaving no harmful residues, making it suitable for green agriculture and organic seed treatment requirements.

[0020] 6. Enhance the multifunctionality of seed treatment. In addition to sterilization and inactivation, this invention can also induce micro-modification of seed surface structure under different discharge conditions, improve seed coat permeability and hydration capacity, and promote germination activity; at the same time, it can also be used as part of a multifunctional treatment platform for surface coating, activation of germination-related enzyme systems, etc., and has integrated and expanded functions. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the plasma grain sterilization device of the present invention.

[0022] Figure 2 This is a partially enlarged schematic diagram of the conveyor belt surface of the plasma grain sterilization device of the present invention, wherein (a) is a front view and (b) is a top view.

[0023] Figure 3 This is a schematic diagram illustrating the mechanism by which the plasma grain sterilization device of the present invention applies ion wind from coplanar electrodes along the surface of the grain to the seed surface.

[0024] Figure 4 This is a schematic diagram of the nanosecond pulse power supply module of the plasma grain sterilization device of the present invention.

[0025] In the diagram: 1-Conveyor belt mechanism, 2-Safety protection structure, 3-Nanosecond pulse power supply module, 4-Drive motor, 5-Transmission component, 6-High voltage electrode, 7-Flexible insulating substrate, 8-Conveyor belt surface, 9-Grounding electrode, 100-Seed, 301-Charging port, 302-DC battery, 303-Boost module, 304-PWM pulse generator, 305-IGBT circuit switch, 306-High frequency transformer, 307-Equivalent grounding terminal, 308-Reactor equivalent load. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0027] like Figures 1 to 4 As shown: The plasma grain sterilization device of this embodiment includes: a conveyor belt mechanism 1, a high-voltage electrode 6, a grounding electrode 9, a nanosecond pulse power supply module 3, an electrical control unit, and a safety protection structure 2. The conveyor belt mechanism 1 includes a conveyor belt made of insulating or heat-resistant material; the high-voltage electrode 6 and the grounding electrode 9 are arranged in an alternating manner on the surface 8 of the conveyor belt, with each group of high-voltage electrode 6 and grounding electrode 9 placed opposite each other, with a height of 0.1-1mm. The edges of the high-voltage electrode 6 and the grounding electrode 9 are covered with insulating material, forming a continuous micro-slope electrode arrangement; the high-voltage electrode 6 is connected to the nanosecond pulse power supply module 3 to form a surface discharge; during the discharge process, plasma is excited on the surface of the high-voltage electrode 6 to form a surface plasma sliding wind; the low-speed conveyor belt, with a conveying speed of 0.2-0.4 m / min, is used to drive the seeds to continuously tumble in the plasma action zone and receive multi-angle treatment. The conveying speed depends on the following theoretical basis: theoretically, as long as the tangential force generated by the local ion wind is in the range of tens to hundreds of micronewtons, it is sufficient to overcome the rolling resistance of the seeds and drive them to tumble; according to this range, the required local wind speed is usually in the range of 0.5-2 m / s; and the conveyor belt speed of 0.2-0.4 m / min provides sufficient residence time for multiple tumbling.

[0028] The working mechanism of this invention: (1) The high-voltage electrode 6 and the ground electrode 9, which are placed opposite each other, not only generate uniform plasma on the surface of the conveyor belt under high-voltage excitation, but also guide the generation of local thrust difference in opposite directions. (2) The plasma slip wind of the staggered high voltage electrode 6 and the ground electrode 9 during the discharge process further applies ion wind with staggered distribution direction to the seed.

[0029] (3) The superimposed ion winds in the staggered distribution direction act on the granular seeds, causing them to roll, jump and flip on the conveyor belt like a vibrating screen; (4) Ensure that the seeds are fully exposed throughout the treatment process to improve the uniformity of plasma treatment.

[0030] This invention employs the following plasma type: (1) The present invention uses atmospheric plasma discharge at normal pressure, preferably using pulsed high-voltage excitation mode (nanosecond pulse or microsecond pulse). (2) The discharge gap is close to the surface of the conveyor belt to form a high-intensity surface-sliding plasma, while avoiding damage to the seeds.

[0031] The electronic control unit of this invention integrates a transmission speed control module, a voltage waveform adjustment module, an electrode spacing adjustment module, and a humidity detection module to regulate the plasma state in real time. The invention also includes overcurrent protection, leakage protection, and automatic shutdown interlocking mechanisms to ensure the safety of personnel and equipment.

[0032] In the coplanar electrode structure formed by the staggered high-voltage electrodes 6 and grounding electrodes 9, the electrode spacing is a key factor determining the uniformity of surface discharge, discharge intensity, and ion wind driving capability. Too small a spacing leads to excessively low breakdown voltage, excessively strong local discharge, and easy electrode ablation; too large a spacing results in discontinuous surface discharge, decreased plasma density, and weakened ion wind, thus reducing seed tumbling efficiency. Considering the breakdown field strength of air at normal pressure (approximately 3 kV / mm), the surface discharge extension characteristics, and the seed size and trajectory, the electrode spacing of this invention is 0.5-1 times the characteristic size of the seed, i.e., 3-6 mm. This ensures discharge stability while generating a uniformly covered plasma region using a suitable surface discharge channel length, and maintains sufficient ion wind thrust to continuously tumble the seeds during transport. This balances the concentration of active seeds while ensuring structural durability and processing uniformity.

[0033] The surface discharge structure based on staggered high-voltage electrodes and grounding electrodes described in this invention possesses a unique synergistic mechanism of electrode tip discharge and bidirectional non-thermal plasma ion wind. During operation, the device continuously processes seeds or grains according to the following steps: 1. Pretreatment and Fabric Laying Stage Grains or seeds first enter the feeding section through a feeding mechanism, where they are graded by particle size and impurities are removed by a vibrating screening device. After being metered, the grains are evenly spread on the conveyor belt in a single layer or thin layer to ensure that there is free space for the particles to move and to avoid stacking that could cause obstruction.

[0034] 2. Surface Plasma Excitation Stage As the conveyor belt moves slowly forward (0.2-0.4 m / min), the seeds enter the discharge treatment area. In this area, the staggered electrodes, under nanosecond-level high-voltage pulse excitation, instantaneously form a high-intensity surface-slip discharge, creating a stable plasma slip channel along the surface of the insulating layer. This generates a large number of active species, such as O*, OH, NOx, electrons, ions, and ultraviolet photons.

[0035] 3. Plasma-slip wind co-driven stage The space charge acceleration accompanying surface discharge generates a sliding airflow along the electrode normal, with wind speeds reaching 0.3-1.2 m / s. This ionic wind acts on the seed sidewalls and contact surfaces, enhancing the driving force in the rolling direction, overcoming the sliding friction limitations caused by traditional purely mechanical conveying, and causing the seeds to undergo periodic lifting and rolling during the conveying process.

[0036] 4. Multi-angle, fully enclosed plasma interaction stage The staggered electrode structure causes the seed surface to constantly change orientation along its path, enabling full coverage of the surface in different directions by plasma active particles. Furthermore, by setting up upper and lower bipolar electrodes, the seeds can be placed in a plasma "clamping and surrounding" zone, achieving a three-dimensional dynamic treatment effect and improving sterilization uniformity and depth of action.

[0037] 5. Post-treatment discharge and performance recovery stage After the discharge treatment is completed, the seeds enter the degradation zone via a conveyor belt. Here, atmospheric pressure airflow and infrared detection are used to restore the seed temperature and allow residual ozone and NOx to dissipate. The system is also equipped with an exhaust system and an exhaust gas adsorption module to ensure no secondary pollution.

[0038] In this process: non-mechanical structures induce particle movement, significantly reducing equipment complexity and maintenance costs; plasma sliding wind and micro-geometric disturbances work together to construct an active self-driven rolling path; dynamic seed rotation enables non-thermal, non-contact, and all-around processing, which is significantly better than traditional linear through-processing methods; no changes to the original seed structure or addition of reagents are required, making it green and environmentally friendly.

[0039] The plasma grain sterilization device of this embodiment includes: a conveyor belt mechanism 1, a safety protection structure 2, a nanosecond pulse power module 3, a drive motor 4 and a transmission assembly 5, and a coplanar discharge electrode structure embedded in the conveyor belt of the conveyor belt mechanism 1, which includes a high-voltage electrode 6, a grounding electrode 9, and a flexible insulating substrate 7 forming the conveyor belt body; the above components form a continuous flow processing platform, the grain material is placed on the surface 8 of the conveyor belt, and is driven by the drive motor 4 to be conveyed, and the plasma sterilization process is completed in the conveying path.

[0040] The coplanar discharge electrode structure consists of multiple staggered strip electrodes printed or bonded to a flexible insulating substrate 7 of the conveyor belt; the high-voltage electrode 6 and the grounding electrode 9 are coplanarly embedded on the surface 8 of the conveyor belt; the high-voltage electrode 6 and the grounding electrode 9 are arranged in a periodic staggered manner, i.e., high voltage-grounding-high voltage-grounding... forming a uniform discharge unit; the edge distance between each group of high-voltage electrode 6 and grounding electrode 9 is 0.4-0.6 mm; The high-voltage electrode 6 and the grounding electrode 9 are both 0.4 mm wide, and there is a 0.5 mm gap between them. The high-voltage electrode 6 and the grounding electrode 9 are constructed by silver paste printing or copper foil hot pressing, and can be processed on flexible media (such as polyimide film, PET, PTFE, etc.) to ensure good flexibility and heat resistance.

[0041] This coplanar discharge electrode structure forms a surface dielectric barrier discharge (SDBD) region, which can excite uniform cold plasma without generating an electric arc, making it suitable for low-temperature sterilization of heat-sensitive materials such as grains.

[0042] The coplanar discharge electrode structure is connected to the nanosecond pulse power supply module 3: The nanosecond pulse power supply module 3 is an adjustable high-frequency pulse or AC source with an output peak voltage of 10–40 kV and a frequency range of 1–10 kHz. The output of nanosecond pulse power module 3 is connected to high voltage electrode 6 through resistor-capacitor current limiting and matching circuit, and grounding electrode 9 is connected to the ground wire of electrical control box. The nanosecond pulse power module 3 is equipped with a main control chip, a PWM voltage regulation module, a boost module, and a high-frequency transformer to control the overall discharge start / stop, power regulation, and abnormal protection. The principle of the high-voltage pulse power output of nanosecond pulse power module 3 is as follows: Figure 4 As shown, its basic principle circuit consists of a charging port 301, a DC battery 302, a boost module 303, a PWM pulse generator 304, an IGBT circuit switch 305, a high-frequency transformer 306, an equivalent ground terminal 307, and a reactor equivalent load 308. The DC battery 302 is supplied with a voltage of 7.4V, which directly powers the PWM pulse generator 304 and the IGBT drive circuit. The IGBT drive circuit then powers the IGBT circuit switch 305. The DC voltage is boosted to 30V by the boost module 303. The PWM pulse generator 304 can generate a square wave signal with an amplitude of 7-25V, a duty cycle of 1%-90%, and a frequency of 1Hz. The current is boosted again by the boost module 303 and then transmitted to the high-frequency transformer 306. Its final output is connected to the reactor equivalent load 308 and the equivalent ground terminal 307. When the power switch is turned on, the pulse circuit can generate a high voltage of 0-10kV.

[0043] To prevent static electricity buildup or leakage, an insulating layer and a metal grounding mesh are installed on the back of the conveyor belt.

[0044] The discharge intensity, frequency, duty cycle and other parameters can be adjusted by the electronic control unit to achieve different sterilization intensities and gas composition requirements.

[0045] When the device is powered on, the electronic control unit first performs initialization tests on all modules of the machine. After confirming that there are no errors, the control unit starts the nanosecond pulse power module 3 and the conveyor belt mechanism 1.

[0046] Position sensors or switches are installed at key locations on the device, such as protective doors, inspection ports, and emergency stop buttons. These sensors, linked to the circuitry or signals of the electrical control unit, synchronize the assessment of the device's operating status and safety conditions. For example, if a protective door is opened or the emergency stop button is pressed, the electrical control unit will immediately cut off the nanosecond pulse power module 3 from the conveyor belt mechanism 1 to prevent personnel from coming into contact with high-voltage or moving parts and causing injury. Its function is to monitor the safety status in real time during device operation, ensuring that the equipment can only operate when all protective measures are in place and the operating environment is safe, thereby avoiding misoperation and accidents, and protecting the safety of operators and equipment.

[0047] The following is the working process of the device in this embodiment: 1. Grain material loading and spreading The grain raw materials are evenly spread onto the surface 8 of the conveyor belt by a front-end feeding device, such as a screw conveyor or a vibrating distributor. To ensure the processing effect, the surface 8 of the conveyor belt is equipped with a slight height-limiting sidewall to prevent the material from rolling off. The thickness of the grain spread is controlled between 5-20 mm to ensure that the upper surface is fully exposed to the plasma area.

[0048] 2. Plasma excitation and reaction region formation When the conveyor belt reaches the coplanar discharge region, at the high-voltage electrode 6 and the ground electrode 9, the nanosecond pulse power module 3 begins to output a pulsed high voltage, forming a surface dielectric barrier discharge between the coplanar electrodes constructed on the flexible insulating substrate 7. This discharge forms a thin layer of plasma-active region above the surface of the conveyor belt, continuously covering the grain surface.

[0049] This plasma layer contains abundant reactive species, such as: reactive oxygen species (O3, O, OH, ¹O2); reactive nitrogen species (NO, NO2); ultraviolet photons (200~280 nm); low-energy electrons and high-energy neutral molecules; The active species interact chemically and physically with microorganisms (bacteria, molds, yeasts, etc.) on the surface of grains, causing cell wall rupture, protein denaturation, or DNA / RNA chain breaks, thereby achieving highly efficient disinfection.

[0050] 3. Control of operating parameters in the discharge region Conveyor belt speed control: The device can adjust the conveyor belt speed according to the type of grain and disinfection requirements. The normal setting is 0.2-0.8 m / min, and the processing time is usually 15-60 seconds.

[0051] Power supply parameter adjustment: Users can set the output voltage, frequency (10–50 kHz) and duty cycle to optimize discharge intensity and uniformity.

[0052] Atmosphere conditioning: Air is used as the discharge gas by default, but auxiliary gases (such as O2 or N2) can be added to adjust the product composition. For example, adding a small amount of O2 can increase the concentration of O3 and OH.

[0053] 4. Disinfection Mechanism and Process Characteristics Plasma provides a triple treatment effect on the grain surface: a. Physical sterilization: High-energy particles, ultraviolet light, and electric fields damage the structure of microorganisms; b. Chemical sterilization: O3, OH, etc. react with cell components, causing irreversible damage; c. Surface modification: Mild oxidation treatment can reduce the risk of lipid oxidation on the surface of grains and delay spoilage.

[0054] Meanwhile, this process is non-thermal, with minimal temperature increase in the grain (usually not exceeding 40°C), ensuring that nutrients such as starch and protein are not damaged.

[0055] 5. Grain unloading and processing completed. After disinfection, the grain will be conveyed out of the discharge end via a conveyor belt, ready to be connected to the next process (such as packaging, cooling, air separation, etc.). The system supports continuous 24-hour operation, and the electrode structure on the conveyor belt surface is detachable and replaceable, making it easy to maintain.

[0056] The device in this embodiment can achieve automatic shutdown due to abnormal discharge, electrode overheating alarm, self-diagnosis and operation log storage functions through the electronic control unit.

[0057] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A plasma grain sterilization device, characterized in that: The system includes a conveyor belt mechanism (1), a nanosecond pulse power module (3), an electrical control unit, and a safety protection structure (2). The conveyor belt mechanism (1) includes a conveyor belt and a transmission assembly (5). The conveyor belt is connected to a drive motor (4) through the transmission assembly (5). A flexible insulating substrate (7) is provided on the surface of the conveyor belt. A high-voltage electrode (6) and a grounding electrode (9) are arranged in an alternating manner on the flexible insulating substrate (7). The bottoms of the high-voltage electrode (6) and the grounding electrode (9) are coplanarly embedded in the flexible insulating substrate (7), and their surfaces are insulated to form a periodic micro-slope electrode structure. The safety protection structure (2) is provided on both sides of the conveyor belt. The high-voltage electrode (6) is connected to the nanosecond pulse power supply module (3) to excite surface discharge and generate plasma slip wind; The grounding electrode (9) is connected to the electronic control unit and forms a coplanar discharge circuit with the high-voltage electrode (6); The electronic control unit includes a processing module, a transmission speed control module, a voltage waveform adjustment module, and a humidity monitoring module. The transmission speed control module, voltage waveform adjustment module, and humidity monitoring module are electrically connected to the processing module, respectively, and are used to coordinate the control of plasma generation and seed tumbling behavior. The electronic control unit is electrically connected to the nanosecond pulse power supply module (3) and the conveyor belt mechanism (1).

2. The plasma grain sterilization device according to claim 1, characterized in that: The nanosecond pulse power module (3) includes: a charging port (301), a DC battery (302), a boost module (303), a PWM pulse generator (304), an IGBT switch (305), a high-frequency transformer (306), an equivalent ground terminal (307), and a reactor equivalent load (308). The DC battery (302) is connected in parallel with the charging port (301); the boost module (303) is electrically connected to the DC battery (302), the PWM pulse generator (304), and the high-frequency transformer (306); the PWM pulse generator (304) is electrically connected to the IGBT switch (305); the IGBT switch (305) is electrically connected to the high-frequency transformer (306); the high-frequency transformer (306) is electrically connected to the reactor equivalent load (308); and the high-frequency transformer (306) is electrically connected to the equivalent ground terminal (307).

3. The plasma grain sterilization device according to claim 2, characterized in that: The transmission belt of the conveyor belt mechanism (1) runs at a speed of 0.2–0.4 m / min, enabling the seeds to achieve self-driven tumbling and multi-faceted processing under the action of plasma.

4. The plasma grain sterilization device according to claim 3, characterized in that: The width of the high voltage electrode (6) and the grounding electrode (9) is 0.3-0.5 mm, the spacing is 0.4-0.6 mm, and the height is 0.1-1 mm. The materials of the high voltage electrode (6) and the grounding electrode (9) are silver paste or copper foil, and the material of the flexible insulating substrate (7) is polyimide, PET or PTFE flexible insulating material.

5. The plasma grain sterilization device according to claim 4, characterized in that: The nanosecond pulse power supply module (3) has an output peak voltage of 10-40 kV, a frequency of 1-10 kHz, and a duty cycle of 1%-90%.

6. The plasma grain sterilization device according to claim 5, characterized in that: The safety protection structure (2) on both sides of the conveyor belt is a slight edge-blocking structure, which is used to limit the thickness of the grain spreading material to between 5-20 mm to avoid stacking and obscuring.

7. The plasma grain sterilization device according to claim 6, characterized in that: The electronic control unit also includes an atmosphere conditioning module connected to the processor module, which can be connected to oxygen or nitrogen auxiliary gas to adjust the composition of plasma active species.

8. The plasma grain sterilization device according to claim 7, characterized in that: The conveyor belt mechanism (1) is provided with a degradation zone at the rear, equipped with an exhaust module and an exhaust gas adsorption module, for treating residual ozone and NOx.

9. The plasma grain sterilization device according to claim 8, characterized in that: The high-voltage electrode (6) and the grounding electrode (9) are arranged in an alternating high-voltage-grounding-high-voltage configuration to form a continuous and uniform surface discharge unit with a discharge gap of 3-6 mm.

10. The plasma grain sterilization device according to claim 9, characterized in that: The electronic control unit also includes an infrared detection module connected to the processor module, used to monitor seed temperature and treatment effect in real time, and the data is fed back to the electronic control unit for adaptive parameter adjustment; the electronic control unit also includes a position sensor and an emergency stop button connected to the processor module respectively, which can automatically cut off the high voltage power supply and transmission module when triggered.

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