A negative pressure drainage type sliding arc discharge plasma seed treatment system and method

Abstract

This invention relates to a negative pressure-guided sliding arc discharge plasma seed treatment system and method. The system includes: a plasma generator comprising a sliding arc electrode and a power supply, the sliding arc electrode being arranged in pairs and connected to the two ends of the power supply to generate plasma gas; a screen, disposed opposite to the plasma generator, the screen having mesh openings sized to prevent seed penetration while allowing plasma gas to pass through; a working area gas guiding device, including a negative pressure source providing negative pressure to guide the plasma gas generated on one side of the screen to the other side; and a flow conduit connected to the negative pressure source, providing a flow channel for the plasma attracted by the negative pressure. This technical solution facilitates the automation of plasma seed treatment applications.

Description

Technical Field

[0001] This invention relates to the field of atmospheric pressure discharge plasma technology, and in particular to a negative pressure induced flow sliding arc discharge plasma seed treatment system and method. Background Technology

[0002] Plasma, as a high-energy state of matter, has seen rapid development and widespread application in fields such as environment and energy, materials, biomedicine, and military science. Low-temperature plasma surface modification technology, due to its moderate power density, high efficiency, low energy consumption, and environmental friendliness, has significant advantages among material surface modification methods. Low-temperature plasma sterilization technology, with its advantages of short processing time, good sterilization effect, and no impact on quality, is a research hotspot in food cold sterilization technology. Plasma gasification technology, due to its high efficiency, environmental friendliness, and high energy conversion rate, is an effective way to harmlessly treat solid waste resources. Atmospheric pressure low-temperature plasma, due to its safety, reliability, and ability to directly act on biological tissues, has seen rapid development in the biomedical field.

[0003] Compared to low-pressure discharge plasma, atmospheric pressure discharge plasma can be generated and applied under open atmospheric pressure conditions. It has advantages such as simple plasma generation and maintenance systems, good mobility, and low manufacturing and maintenance costs, which are conducive to the realization of automation applications and the improvement of work efficiency, and conducive to the continuous expansion of plasma application fields.

[0004] Seeds are the life-sustaining carriers of species, expanding their ecological niche space, and are the most basic agricultural production material, providing indispensable food for humans and animals. In agricultural production, various crop seeds are usually treated in different ways before sowing to improve seed vigor and sowing quality, thus directly affecting germination, production, yield, and the nutritional composition of the fruit. Plasma seed treatment technology uses high-energy aggregated matter to treat seeds before sowing, producing long-lasting positive biological effects on seeds, and has been widely researched and applied. However, existing plasma seed treatment devices are mostly experimental research devices, with limitations such as limited processing capacity and inability to achieve continuous production. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an atmospheric pressure discharge plasma seed treatment system to improve the efficiency and quality of seed treatment.

[0006] To solve the above-mentioned technical problems, the technical solution provided by the present invention includes:

[0007] A negative pressure-guided sliding arc discharge plasma seed treatment system, characterized in that the system comprises: a plasma generator, the plasma generator including a sliding arc electrode and a power supply, the sliding arc electrode being arranged in pairs and respectively connected to the two ends of the power supply to generate plasma gas; a screen, the screen being arranged opposite to the plasma generator, the screen having mesh openings, the size of which is used to prevent seeds from passing through while allowing plasma gas to pass through; a working area gas guiding device, including a negative pressure source, the negative pressure source providing negative pressure to guide the plasma gas generated on one side of the screen to the other side of the screen; and a flow pipeline, the flow pipeline being connected to the negative pressure source for providing a flow channel for the plasma attracted by the negative pressure.

[0008] Preferably, each pair of sliding arc electrodes in the paired arrangement is mirror-image arranged.

[0009] Preferably, the plasma generating device includes multiple pairs of electrodes forming a sliding arc electrode group; the sliding arc electrode group is separated by insulating partitions that separate the pairs of sliding arc electrodes.

[0010] Preferably, the sliding arc electrode includes a rod-shaped electrode, a circular electrode, a knife-shaped electrode, a triangular electrode, and an arc-shaped electrode.

[0011] Preferably, the knife-shaped electrode has a curved lower edge and an overall knife-shaped cross-section.

[0012] Preferably, the mesh of the sieve is circular or rectangular; when the mesh of the sieve is circular, the diameter of the circular mesh is determined according to the width of the seed; when the mesh of the sieve is oblong, the sieve size is determined according to the thickness of the seed.

[0013] Preferably, the mesh of the sieve is a square mesh with a mesh size of 1mm*1mm.

[0014] Preferably, the screen is connected to a vibration generating mechanism to drive relative vibration between the screen and the seed; the vibration occurs along a direction relative to the plane of the screen, or along a direction perpendicular to the plane of the screen.

[0015] Preferably, a tail gas treatment unit is provided downstream of the negative pressure source, which is used to treat the plasma gas that has finished working to avoid gas pollution.

[0016] as well as

[0017] A negative pressure induced sliding arc discharge plasma seed treatment method is provided, wherein the seed is treated by a negative pressure induced sliding arc discharge plasma seed treatment system as described in any one of the above claims, wherein the seed surface is saturated by continuously conveying the seed to receive sliding arc discharge plasma treatment in two directions.

[0018] The above scheme uses a perforated screen to transport seeds, allowing the working airflow to pass through the screen without forming a large component in the horizontal direction of the transport plane. This avoids disorderly movement of seeds on the transport screen and reduces the difficulty of airflow-driven plasma processing of seeds. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings.

[0020] Figure 1 This is a schematic diagram of a negative pressure drainage sliding arc discharge plasma seed treatment device according to an embodiment of this disclosure;

[0021] Figure 2 This is a schematic diagram of the electrode array of a sliding arc discharge plasma generator according to an embodiment of this disclosure;

[0022] Figure 3a This is a schematic diagram of a sliding arc electrode structure according to an embodiment of the present disclosure;

[0023] Figure 3b This is a schematic diagram of a sliding arc electrode structure according to an embodiment of the present disclosure;

[0024] Figure 3c This is a schematic diagram of a sliding arc electrode structure according to an embodiment of the present disclosure;

[0025] Figure 3d This is a schematic diagram of a sliding arc electrode structure according to an embodiment of the present disclosure;

[0026] Figure 3e This is a schematic diagram of a sliding arc electrode structure according to an embodiment of the present disclosure;

[0027] Figure 4 This is a schematic diagram of the operation of a conveying screen according to an embodiment of the present disclosure;

[0028] Figure 5 This is a schematic diagram of a seed delivery scheme according to an embodiment of the present disclosure;

[0029] Figure 6 This is a schematic diagram of a seed saturation treatment scheme according to an embodiment of this disclosure;

[0030] Figure 7 This is a statistical chart of seed germination related to an embodiment of this disclosure;

[0031] Figure 8 This is a statistical chart of seedling root lengths related to an embodiment of this disclosure.

[0032] Figure Labels

[0033] 1-Negative pressure source; 2-Plasma treatment chamber; 3-Gas flow system for working area; 4-Seed; 5-Plasma; 6-Sliding arc electrode; 7-Plasma power supply; 8-Screen; 9-Exhaust gas treatment section; 10-Insulating partition; 11-Safety screen. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] In the description of the embodiments of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the term "connected" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0036] Throughout the text, the terms “top,” “bottom,” “above,” “below,” and “on top” refer to the relative positions of components of the device, such as the relative positions of the top and bottom substrates within the device. It is understood that the device is multifunctional and independent of its spatial orientation.

[0037] To facilitate understanding of the embodiments of this application, the following will be described in conjunction with the accompanying drawings. Figures 1-8 The following specific embodiments are provided for further explanation and illustration. These embodiments do not constitute a limitation on the embodiments of this application.

[0038] Example 1

[0039] This embodiment discloses a negative pressure drainage sliding arc discharge plasma seed treatment system, which treats plant seeds by sliding arc discharge plasma.

[0040] The system includes major functional modules such as a sliding arc discharge plasma generator, a working area gas flow device, a plasma processing chamber, and a seed delivery device.

[0041] like Figure 1 As shown, the sliding arc discharge plasma generator mainly consists of a sliding arc electrode 6 and a plasma power supply 7. The plasma power supply 7 is used to drive the sliding arc electrode 6 to discharge and generate plasma 5, which serves as the plasma source for this system and provides plasma gas for the entire system.

[0042] The sliding arc electrode and the screen can be disposed inside the plasma processing chamber 2 so that the plasma gas can process the seed 4 in a relatively sealed space.

[0043] The sliding arc electrode 6 includes paired sliding arc electrode units. The two output terminals of the plasma power supply are each connected to one of the sliding arc electrode units to apply a driving voltage between the paired sliding arc electrode units. The output voltage of the plasma power supply 7 is alternating current (AC), preferably a sine wave. More preferably, the AC output voltage amplitude is 20kV and the frequency is 6kHz.

[0044] Preferably, such as Figure 2 As shown, multiple pairs of electrodes can be configured to form a sliding arc electrode group, expanding the working area and improving working efficiency. The sliding arc electrode group is separated from the paired sliding arc electrodes 6 by an insulating partition 10, ensuring that adjacent sliding arcs do not short-circuit. The sliding arc electrode group is driven by a series circuit, or the paired sliding arc electrodes can be directly driven individually by a plasma power supply.

[0045] The paired sliding arc electrode units are preferably symmetrical in shape, including but not limited to, such as... Figure 3a The rod-shaped electrode, such as Figure 3b The circular electrode, such as Figure 1 and Figure 3c The knife-shaped electrode shown; Figure 3d The triangular electrode shown, and Figure 3e The circular arc-shaped electrode is shown.

[0046] In this specific embodiment, the preferred method is as follows: Figure 1 and stated Figure 3cThe aforementioned knife-shaped electrode has a curved lower edge and an overall knife-shaped cross-section. This type of electrode can output plasma over a relatively wide area, thereby providing a larger processing area and enabling more seed treatment. Furthermore, the curved lower edge of most knife-shaped electrodes can form plasma clusters with a relatively uniform density, resulting in better seed treatment.

[0047] Furthermore, the electrode material of the sliding arc electrode 6 can be copper, tungsten, or stainless steel, with stainless steel being the preferred material due to its stable performance and excellent cost control.

[0048] The seed conveying device includes a conveying screen 8 with a hollow structure, through which seeds are carried, and more preferably, seeds 4 are conveyed through the screen 8.

[0049] The screen is positioned opposite to the sliding arc discharge plasma generator so that the plasma gas flow generated by the sliding arc discharge plasma generator can be sprayed onto the seeds on the screen to complete the seed processing.

[0050] In this specific embodiment, using a screen as the seed carrier allows the plasma gas flow to pass through the conveying screen without forming a large component in the horizontal direction of the conveying plane. This avoids the seeds on the conveying screen moving disorderly under the blowing of the gas flow, and reduces the difficulty of gas flow-driven plasma processing of seeds.

[0051] In this specific embodiment, preferably, the sieve is made of Teflon material, and the mesh is circular or rectangular. The size of the mesh can be determined according to the seed diameter to find an optimal sieve mesh pattern. One preferred determination rule includes that when the sieve mesh is circular, the diameter of the circular mesh is determined according to the seed width; when the sieve mesh is oblong, the sieve size is determined according to the seed thickness. Furthermore, it is also preferable to set the sieve mesh to have square mesh openings with a mesh size of 1mm*1mm.

[0052] In this specific embodiment, the screen can be used as part of a transport vehicle, that is, the screen is movable. Of course, the screen can also be used only as a carrying tool, that is, the screen is immovable during the seed processing.

[0053] When the screen is configured as a movable conveyor, the direction of screen movement includes horizontal conveying and climbing conveying (see attached image). Figure 4 Alternatively, seeds can be transported downhill to meet the different environmental requirements for seed transport. Orderly transport of seeds within the plasma working area improves the effectiveness and efficiency of plasma seed processing.

[0054] More preferably, the seeds and the sieve can be relatively stationary or substantially relatively stationary, or the sieve can be connected to a vibration generating mechanism to drive relative vibration between the sieve and the seeds. The vibration can occur along the plane of the sieve, or along a plane perpendicular to the sieve, or can form a combined motion as needed.

[0055] For situations where seeds accumulate or obstruct each other on the conveyor screen, a vibration conveying system can be used to evenly and orderly transport the seeds onto the screen into the working area for plasma seed treatment. This improves the quality of seed treatment and also increases work efficiency.

[0056] Below the screen, on the side opposite to the sliding arc electrode, a working area gas guiding device is provided. The gas guiding device is equipped with a working area gas flow device. The working area gas guiding device is mainly used to guide the gas in the working area to flow in a predetermined direction, so that the gas flow field in the working area is uniform and stable, thereby improving the quality of seed treatment.

[0057] In this specific embodiment, the working area gas diversion device includes a negative pressure source that provides negative pressure to guide the plasma gas on the upper surface of the screen to below the screen. It also includes a flow conduit opposite the screen and connected to the negative pressure source, providing a flow channel for the plasma attracted by the negative pressure.

[0058] More preferably, a tail gas treatment unit is provided downstream of the negative pressure source. The tail gas treatment unit 9 is used to treat the plasma gas after it has finished working to prevent gas pollution. The plasma gas tail gas can be treated by means of recycling, etc. The nitrogen oxides in the working tail gas are converted into raw materials for preparing liquid nitrogen fertilizer by recycling and absorption. These can be achieved by existing technology, so they will not be described in detail in this specific embodiment.

[0059] A gas diversion device in the working area guides the plasma discharge along the sliding arc electrode, generating a large volume of plasma under atmospheric pressure. Negative pressure diversion is used to directionally guide the gas in the working area, with the gas flow direction aligned with the development direction of the sliding arc. On the flow plane containing the sliding arc electrodes, the two electrodes are mirror-image distributed, with the line connecting them perpendicular to the gas flow direction. The uniformity and stability of the flow field ensure a uniform and continuous plasma distribution in the working area. This achieves laminar flow of gas along the development direction of the sliding arc while maintaining the uniformity and stability of the flow field in the working area.

[0060] More preferably, in this specific embodiment, the gas flow in the plasma working area is driven by negative pressure, and the gas flow is a uniformly distributed laminar flow with a flow velocity of 5 m / s.

[0061] Example 2

[0062] This embodiment 2 provides a negative pressure induced flow sliding arc discharge plasma seed treatment method, which is implemented using a negative pressure induced flow sliding arc discharge plasma seed treatment system described in embodiment 1.

[0063] In this embodiment, the negative pressure drainage type sliding arc discharge plasma seed treatment method includes the following steps:

[0064] Step 1: Start the seed delivery system, sliding arc discharge plasma generator, and working area gas flow system in sequence.

[0065] Step 2: Turn on the plasma power supply to drive the sliding arc electrode to discharge and generate plasma.

[0066] Step 3: Turn on the induced draft fan to induce negative pressure flow so that the plasma discharge on the sliding arc electrode side passes through the conveying screen, thereby achieving the coverage of both sides of the conveying screen by the sliding arc discharge plasma working area.

[0067] Step 4: Adjust the output voltage and frequency of the plasma power supply and wait for the sliding arc discharge plasma generator to stabilize.

[0068] Step 5: The seeds are evenly distributed on the conveyor screen through seeding, sorting, and dropping.

[0069] Step 6: The seeds are conveyed by the conveying screen into the stable negative pressure induced flow sliding arc discharge plasma working area.

[0070] Step 7: Adjust the working speed of the conveying screen to control the time it takes for the seeds to pass through the plasma working area.

[0071] Step 8: Collect the seeds after plasma seed treatment by dropping, collecting, and packaging.

[0072] Using the above method, this embodiment utilizes the uniform and stable plasma flow field of the negative pressure induced sliding arc discharge plasma seed treatment system to process seeds, enabling batch processing of seeds and achieving excellent processing results.

[0073] Example 3

[0074] The present invention relates to a method for seed treatment using plasma, which can be performed using the system described in Example 1 and the method described in Example 2 when operating the system.

[0075] In this embodiment, the seed treatment method includes the following steps:

[0076] Before plasma seed treatment, seeds should be sorted to remove impurities such as stones, stems, and broken leaves. Seeds that are dry, have damaged seed coats, are incomplete, or are insect-eaten should be screened out to improve seed purity.

[0077] The sorting method is as follows: The seeds are winnowed 2-3 times using a winnowing machine; the winnowed seeds are then screened a second time using a combination of sieves with different mesh sizes to complete the seed sorting. For optimal selection, gravity separation, image recognition, and other methods can be used to further improve seed purity, remove bad seeds, and select plump, highly mature seeds. The seeds to be treated should be carefully selected, and their purity, cleanliness, moisture content, and germination rate should meet national standards.

[0078] The plasma seed treatment process involves selecting parameter combinations based on seed type. Controlled parameters include plasma parameters such as electron temperature and electron number density, energy parameters coupled to the plasma such as discharge voltage and current, and plasma power, as well as processing time and working gas parameters such as gas type and ratio. Plasma parameters such as electron temperature and electron number density are adjusted according to seed type. Plasma parameters are achieved by changing electrical parameters, discharge electrode parameters, and working gas parameters. The plasma discharge voltage and current are adjusted via the plasma power supply. A discharge voltage of 20kV is preferred. The processing time is controlled by adjusting the speed of the conveyor screen, regulating the seed's transit time within the plasma working area. A processing time of 10s is preferred. A gas distribution system, consisting of gas cylinders, gas lines, valves, and pressure gauges, is used to modify the type and ratio of the working gas within the plasma treatment chamber, thereby controlling the gas parameters in the working area. Atmospheric pressure is preferred, and air and helium are preferred working gases.

[0079] More preferably, such as Figure 7 As shown, the seed surface can be saturated by continuously feeding seeds to receive sliding arc discharge plasma treatment in two directions. Figure 7 In the view described, the plasma gas flows from top to bottom during the first treatment and from bottom to top during the second treatment. To prevent the airflow from scattering the seeds, a safety screen is placed above the screen carrying the seeds during the second treatment to prevent the seeds from being blown away.

[0080] Taking bellflower seeds as an example, bellflower is a perennial herb with economic value in terms of ornamental, edible, and medicinal uses. China, as the largest exporter of bellflower, has a planting area of ​​36 km². 2 The total yield was 70,000 tons. The crop seeds used in this example were bellflower seeds, which were treated with sliding arc discharge plasma. Indoor germination experiments were conducted to determine germination potential, germination rate, and seedling root length.

[0081] Indoor germination experiments were conducted using the paper germination method. Each plasma treatment group was replicated five times, with 50 plasma-treated Platycodon grandiflorus seeds placed in each replicate. A blank control group was set up, with 50 untreated Platycodon grandiflorus seeds placed in the seedbed, replicated five times. Seed germination was recorded starting from the day of sowing. Germination potential was assessed on day 7, and germination rate and seedling root length were assessed on day 18.

[0082] Figure 8 The germination statistics show that the germination potential of the treatment group was 13%, which was stronger than the 3% germination potential of the control group. The germination rate of the treatment group was slightly higher than that of the control group. The root length of the seedlings in the treatment group (52.0925 mm) was greater than that of the control group (49.307 mm). The germination test results indicate that the germination speed and uniformity of the seeds in the sliding arc discharge plasma treatment group were better than those in the blank control group.

[0083] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above description is only a specific embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A negative pressure induced flow sliding arc discharge plasma seed treatment system, characterized in that, The system includes: A plasma generating device, comprising a sliding arc electrode and a power supply, wherein the sliding arc electrodes are arranged in pairs and are respectively connected to the two ends of the power supply to generate plasma gas; A conveying screen, serving as a seed carrier, carries seeds on the side opposite to the plasma generator; the screen is positioned opposite the plasma generator, and the screen has mesh openings of a size designed to prevent seeds from passing through while allowing plasma gas to pass through; The working area gas diversion device includes a negative pressure source that provides negative pressure to guide the plasma gas generated on one side of the screen to the other side of the screen; and a flow pipeline connected to the negative pressure source to provide a flow channel for the plasma attracted by the negative pressure. The gas flow in the plasma working area is driven by the negative pressure, and the gas flow is a uniformly distributed laminar flow with a flow velocity of 5 m / s. The airflow in the working area can pass through the conveying screen without forming a large component in the horizontal direction of the conveying plane, avoiding disordered movement of seeds on the conveying screen, reducing the difficulty of plasma treatment of seeds under airflow drive, and improving the efficiency and quality of seed treatment. The working speed of the conveying screen is controlled to regulate the time the seeds pass through the plasma working area; the processing time is 10 seconds. By continuously feeding seeds to receive sliding arc discharge plasma treatment in two directions, the seed surface is saturated. In the first treatment, the plasma gas flows from top to bottom, and in the second treatment, the plasma gas flows from bottom to top. In order to prevent the airflow from blowing away the seeds, a safety screen is set above the screen carrying the seeds in the second treatment to prevent the seeds from being blown away.

2. The negative pressure drainage type sliding arc discharge plasma seed treatment system according to claim 1, characterized in that, The paired sliding arc electrodes are mirror-image arranged in each pair.

3. The negative pressure drainage type sliding arc discharge plasma seed treatment system according to claim 1, characterized in that, The plasma generator comprises multiple pairs of electrodes forming a sliding arc electrode group; the sliding arc electrode group is separated by insulating partitions that separate the pairs of sliding arc electrodes.

4. The negative pressure drainage type sliding arc discharge plasma seed treatment system according to claim 1, characterized in that, The sliding arc electrode includes rod-shaped electrodes, circular electrodes, knife-shaped electrodes, triangular electrodes, and arc-shaped electrodes.

5. The negative pressure drainage type sliding arc discharge plasma seed treatment system according to claim 4, characterized in that, The knife-shaped electrode has a curved lower edge and an overall knife-shaped cross-section.

6. The negative pressure drainage type sliding arc discharge plasma seed treatment system according to claim 1, characterized in that, The mesh of the sieve is circular or rectangular; when the mesh of the sieve is circular, the diameter of the circular mesh is determined according to the width of the seed; when the mesh of the sieve is oblong, the sieve size is determined according to the thickness of the seed.

7. The negative pressure drainage type sliding arc discharge plasma seed treatment system according to claim 6, characterized in that, The screen has square mesh openings with a mesh size of 1mm*1mm.

8. The negative pressure drainage type sliding arc discharge plasma seed treatment system according to claim 1, characterized in that, The screen is connected to a vibration generating mechanism to drive relative vibration between the screen and the seed; the vibration occurs along a direction relative to the plane of the screen, or along a direction perpendicular to the plane of the screen.

9. The negative pressure drainage type sliding arc discharge plasma seed treatment system according to claim 1, characterized in that, A tail gas treatment unit is provided downstream of the negative pressure source. The tail gas treatment unit is used to treat the plasma gas that has finished working to prevent gas pollution.

10. A method for treating plasma seeds of a negative pressure-guided sliding arc discharge, characterized in that, The method employs a negative pressure drainage sliding arc discharge plasma seed treatment system as described in any one of claims 1-9 to treat the seeds, wherein the seed surface is saturated by continuously conveying the seeds to receive sliding arc discharge plasma treatment in two directions.

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