Atmospheric pressure low-temperature plasma spiral jet device

Abstract

The invention belongs to the technical field of plasmas, and particularly discloses an atmospheric pressure low-temperature plasma spiral jet device which comprises an outer electrode, an inner electrode, a gas supply assembly and a gas inlet assembly, and the inner electrode is located in the outer electrode and connected with the gas inlet assembly; the air supply assembly is located between the inner electrode and the outer electrode, the inner electrode and the outer electrode are insulated through the air supply assembly, a plurality of spiral through grooves are formed in the air supply assembly in the circumferential direction of the air supply assembly, and air supply openings communicated with the spiral through grooves are formed in the end of the air supply assembly. An air inlet and an air outlet are formed in the air inlet assembly, the air inlet is communicated with an air source pipeline, and the air outlet is communicated with the air supply port; the air inlet assembly, the air supply assembly and the outer electrode are mutually connected; a plasma generation area is arranged on the inner side of the outer electrode and located on the side, away from the air inlet assembly, of the air supply assembly, and one end of the inner electrode is located in the plasma generation area. The plasma spiral jet flow can be realized without a mechanical rotating mechanism.

Description

Technical Field

[0001] The present invention relates to the field of plasma technology, in particular to an atmospheric pressure low-temperature plasma spiral jet device. Background Art

[0002] As a key branch of low-temperature plasma technology, atmospheric plasma jets have demonstrated strong potential in numerous fields due to their unique advantages. Their formation process is primarily based on the principle of gas discharge. High-voltage electric fields or high-frequency excitation ionize working gases (such as argon and nitrogen) to form plasma. This technology requires no complex vacuum systems, is simple to set up, and operates stably under atmospheric pressure. The discharge temperature is typically controlled between 100 and 1000°C, significantly lower than traditional thermal plasmas, thus minimizing damage to heat-sensitive materials. During operation, operators precisely control the plasma state by adjusting parameters such as gas flow rate and voltage frequency. The flexible nozzle design allows for adaptability to diverse operating conditions. In the field of material surface modification, plasma jets enhance surface hydrophilicity and adhesion by introducing active particles. In the preparation of nanomaterials, their high-energy environment can be exploited to achieve rapid synthesis and particle size control. In the plasma cleaning process in industries such as semiconductor manufacturing and printing and packaging, plasma jets can effectively remove organic contaminants from material surfaces, providing an ideal substrate for subsequent processes.

[0003] However, traditional plasma jets can only spray along the axis to form a point-like form, and the area of ​​action on the material that can be treated is very small. Current atmospheric plasma jet technology faces significant bottlenecks in large-area processing applications. Due to physical properties, conventional plasma jets are in the form of beam sprays in the axial direction, and their effective area of ​​action is usually only a millimeter-level point-like spot, and the single processing area is extremely limited. If a point-by-point scanning method is used to process large-area materials, the processing efficiency will decrease exponentially with the increase in area, which is difficult to meet the needs of industrial mass production. In existing solutions, in order to adapt to the treatment of large-area surfaces, the jet device usually adopts a rotary spray gun with an eccentric flame hole. The driving mechanism drives the nozzle to rotate and rotate the plasma jet to treat large-area workpiece surfaces; although the rotary spray gun can form a circular scanning trajectory on the workpiece surface through the eccentric flame hole design and the rotating motion of the nozzle, thereby achieving a certain degree of expansion of the processing area, this technical route still has many defects.

[0004] The rotating mechanism requires high-precision servo motors and transmission components, significantly increasing equipment costs. The long-term, high-frequency operation of moving parts can easily lead to mechanical wear and loss of transmission accuracy, resulting in short maintenance cycles and high repair costs. Furthermore, the complexity of the motor drive system increases equipment failure points, making operational stability and reliability difficult to guarantee. Frequent downtime for maintenance, especially in continuous production scenarios, can severely impact production efficiency, hindering the large-scale application of atmospheric plasma jet technology in large-area surface treatment applications.

[0005] Although traditional plasma jet technology is widely used in material surface treatment, it has not yet been applied to large-area and highly uniform jet devices. Summary of the Invention

[0006] The present invention provides an atmospheric pressure low-temperature plasma spiral jet device, the purpose of which is to realize plasma jet without the need for a mechanical rotating mechanism.

[0007] The present invention is achieved through the following technical solutions: an atmospheric pressure low-temperature plasma spiral jet device, comprising an outer electrode, an inner electrode, an air delivery assembly and an air intake assembly, wherein the inner electrode is located inside the outer electrode and connected to the air intake assembly; One end of the gas supply assembly is located inside the outer electrode, and the other end of the gas supply assembly extends out of the outer electrode. The gas supply assembly is located between the inner electrode and the outer electrode, and the inner electrode and the outer electrode are insulated by the gas supply assembly. The gas supply assembly is provided with a plurality of spiral grooves along its circumference, and an end of the gas supply assembly is provided with a gas supply port communicating with the spiral grooves. The air inlet assembly is provided with an air inlet and an air outlet, the air inlet is connected to the air source pipeline, and the air outlet is connected to the air supply port; the air inlet assembly, the air supply assembly and the outer electrode are connected to each other; A plasma generating region is provided on the inner side of the outer electrode. The plasma generating region is located on a side of the gas supply component away from the gas inlet component. One end of the inner electrode is located in the plasma generating region.

[0008] Compared with the existing technology, this solution has the following advantages and beneficial effects: In this scheme, the working gas forms a rotating airflow through the spiral groove in the gas supply component, and is ionized by high voltage breakdown in the plasma generation area to generate a low-temperature (non-equilibrium) plasma spiral jet containing atoms, ions and free radicals, which acts on the material surface to achieve material processing or cleaning of material surface contaminants. It can also be used for material modification.

[0009] The gas supply assembly of this solution is located between the inner and outer electrodes, providing insulation between them. Furthermore, the multiple spiral grooves along its circumference divert the gas flowing out of the gas inlet assembly, ensuring stable and uniform gas flow to the plasma generation zone. Furthermore, the spiral grooves in this solution transport the working gas entering the gas inlet assembly in a spiral pattern, guiding it to form a high-speed rotating airflow, fully ionizing it to produce atoms, ions, and free radicals, thereby enhancing material processing and cleaning capabilities.

[0010] In this scheme, spiral gas supply is used to form a plasma rotating arc, the plasma generation efficiency is high, and the process does not require a mechanical rotating mechanism to achieve a plasma jet.

[0011] The turbulent effect created by the rotating airflow in the plasma generation zone increases the contact area between the gas and the electric field, making the ionization process more complete and reducing energy consumption compared to traditional jet devices. Furthermore, the design without mechanical rotating parts reduces equipment maintenance costs and failure rates, extending the device's service life and improving overall economic benefits. Without the need for complex mechanical structures, the device is compact and easy to install, adapting to a variety of working environments. By adjusting the pitch, depth, and gas flow rate of the spiral grooves, the plasma jet temperature and active particle concentration can be flexibly controlled to meet the differentiated processing requirements of different materials (metals, polymers, biomaterials, etc.), including surface etching, coating preparation, and bio-sterilization.

[0012] The spiral groove design has the effect of diverting and guiding the gas, so that the plasma jet forms a uniform treatment surface on the material surface, avoiding the problem of local over-treatment or under-treatment.

[0013] The insulation of the gas supply assembly effectively isolates the inner and outer electrodes, reducing the risk of high-voltage leakage. Furthermore, the stable flow of the spiral gas prevents localized overheating and arc instability in the plasma generation area, ensuring long-term continuous operation of the equipment. Furthermore, the characteristics of non-equilibrium low-temperature plasma eliminate the need for a high-temperature environment during the treatment process, avoiding the risk of thermal damage to materials and broadening the range of applicable materials.

[0014] Furthermore, the gas supply assembly includes a gas supply connecting flange and a spiral column, the gas supply connecting flange is coaxially fixedly connected to the spiral column, multiple spiral grooves are opened on the spiral column, the spiral column is inserted into the interior of the outer electrode and is close to the inner wall of the outer electrode; the gas supply connecting flange is located on the outside of the outer electrode, and the gas supply port is opened on the gas supply connecting flange.

[0015] Beneficial effects: In this solution, the gas supply connection flange is coaxially fixed to the spiral column, ensuring the stability of gas flow in the spiral groove and avoiding uneven airflow due to eccentricity; at the same time, the flange structure facilitates quick connection with the air intake component and the outer electrode, simplifying the assembly process, reducing installation difficulty, and improving equipment assembly efficiency.

[0016] The spiral grooves on the spiral column directly act on the gas flow path. By closely fitting the inner wall of the outer electrode, gas leakage and turbulent loss are minimized, allowing the gas to flow strictly along a spiral trajectory, enhancing the strength and stability of the rotating airflow and providing a stable gas source for efficient plasma ionization.

[0017] The tight fit between the spiral column and the inner wall of the outer electrode, combined with the sealing design of the flange structure, effectively prevents gas leakage and maintains stable gas pressure in the plasma generation area. At the same time, the gas supply assembly serves as the insulating medium between the inner and outer electrodes. Its tight assembly further enhances the insulation performance, reduces the risk of short circuits during high-voltage discharge, and ensures safe equipment operation.

[0018] Furthermore, one end of the spiral column is fixedly connected to a connecting column, which is coaxially connected to the gas supply connecting flange. The diameter of the connecting column is smaller than the diameter of the spiral column, and an annular buffer cavity is formed between the connecting column and the inner wall of the outer electrode.

[0019] Beneficial effects: The annular buffer chamber in this solution provides a temporary storage space for the gas before entering the spiral groove, effectively alleviating the pressure fluctuation of the output airflow of the air inlet component, allowing the gas to flow smoothly into the spiral groove, avoiding uneven flow velocity in the spiral groove due to airflow impact, and ensuring the stability and consistency of the airflow in the plasma generation area.

[0020] The temporary storage and diffusion of gas in the buffer cavity can balance the local pressure difference when the gas enters the spiral groove, reduce the turbulent noise generated by the gas flow, and at the same time reduce the impact of sudden pressure changes on the gas supply components and electrode structure, thereby extending the service life of the equipment.

[0021] The buffer chamber adjusts the gas residence time within the chamber to accommodate various gas flow rates, depending on the operating conditions. When the air intake is high, the buffer chamber temporarily stores the gas to prevent overloading of the spiral grooves. When the air intake is low, the buffer chamber maintains a stable gas output, improving the device's adaptability under varying operating conditions.

[0022] Furthermore, the bottom of the gas supply connection flange protrudes outward to form a connection boss, and the connection boss is inserted into the interior of the outer electrode.

[0023] Beneficial effects: The connection boss in this solution cooperates with the external electrode to form a mechanical locking structure, ensuring the coaxiality of the gas supply component and the external electrode. During assembly, the external electrode interface can be quickly aligned through the connection boss, reducing installation difficulty, shortening equipment assembly time, and reducing assembly errors.

[0024] Furthermore, a buffer groove is provided at the top of the air supply connection flange, and the air supply port and the air outlet are both communicated with the buffer groove.

[0025] Beneficial effect: The setting of the buffer groove can reduce the difficulty of processing the air supply port and the air outlet. The gas discharged from the air outlet first enters the buffer groove and then is discharged from the air supply port. In this way, the air supply port does not need to be completely aligned with the air outlet, which reduces the processing requirements.

[0026] Furthermore, the air intake assembly includes an air intake connecting flange and a cylinder, the cylinder is connected to the air intake connecting flange, the air inlet is located at the top of the cylinder, and the air outlet is opened on the air intake connecting flange; the air intake connecting flange and the air supply connecting flange overlap with each other and are connected to the top of the outer electrode.

[0027] Beneficial Effects: In this solution, gas flows vertically downward from the inlet at the top of the cylinder to the internal buffer, then flows out through the outlet on the inlet flange and into the spiral groove. This structure facilitates the connection and fixation of the inlet flange to the gas supply assembly and the outer electrode, while the cylinder acts as a buffer space, buffering the working gas and ensuring stable gas delivery.

[0028] Furthermore, an outer electrode flange is fixedly connected to the top of the outer electrode, the air intake connecting flange, the air supply connecting flange and the outer electrode flange are connected to each other, and seals are provided between the air intake connecting flange and the air supply connecting flange and between the air supply connecting flange and the outer electrode flange.

[0029] Beneficial effects: In this solution, the outer electrode flange is fixed on the top of the outer electrode, which facilitates detachable connection with the connecting flanges on the air inlet assembly and the air supply assembly through bolts, making it easy to assemble and facilitate subsequent maintenance and disassembly.

[0030] In addition, in this solution, seals are provided between the air inlet connecting flange and the air supply connecting flange, and between the air supply connecting flange and the outer electrode flange, so as to ensure the airtightness of the connection between the various components and avoid leakage of the working gas.

[0031] Furthermore, the inner electrode includes a coaxially connected electrode head and an electrode column, one end of the electrode column away from the electrode head coaxially passes through the gas supply component and is connected to the gas inlet component, the electrode head is threadedly connected to the electrode column, and one end of the electrode head is located in the plasma generation area.

[0032] Beneficial effects: In this solution, the inner electrode includes an electrode head and an electrode column. The setting of the electrode column provides a connection support position for the installation of the electrode head, and the electrode head is threadedly connected to the electrode column. The length of the electrode head can be fine-tuned by adjusting the screw-in depth of the electrode head thread, and electrode heads of different sizes and materials can be replaced according to the application conditions.

[0033] Furthermore, the plasma generation region is an axisymmetric scaling cavity structure composed of two conical surfaces, and the plasma generation region includes a contracting cone section, a throat and an expanding cone section. The contracting cone section and the expanding cone section are connected in series along the axial direction to form a variable cross-section channel, and the connection between the contracting cone section and the expanding cone section is the throat; the contracting cone section is close to the gas supply assembly, and the end of the inner electrode away from the gas inlet assembly extends out of the contracting cone section.

[0034] Beneficial effects: In this scheme, the inner wall of the outer electrode is a plasma generation zone with a double-conical structure. Its inner diameter first contracts to form a contracting cone section, and then changes to form an expanding cone section. The contracting cone section increases the flow rate of the rotating gas and improves the ionization efficiency; the throat between the contracting cone section and the expanding cone section is the intermediate breakdown area, and the high-frequency pulse breaks through the gas in this area to generate high-density plasma; the expanding cone section can expand the contact area between the plasma and the nuclear fuel surface, forming a wide-area reaction area and guiding the spiral RF ejection, which can effectively increase the plasma area.

[0035] Furthermore, the half cone angle of the contraction cone section is , the semi-cone angle of the expansion cone segment is , and Set to the same angle or different angles, and and The value range is between 25° and 75°.

[0036] Beneficial effects: This solution can be adjusted according to different requirements. and The different angle ratios can be used to adjust the plasma spray area and plasma spray distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings: Figure 1 This is a perspective view of an embodiment of an atmospheric pressure low-temperature plasma spiral jet device of the present invention; Figure 2 This is a longitudinal cross-sectional view of an embodiment of an atmospheric pressure low-temperature plasma spiral jet device of the present invention; Figure 3 An exploded schematic diagram of an atmospheric pressure low-temperature plasma spiral jet device according to an embodiment of the present invention from one perspective; Figure 4 This is an exploded schematic diagram of another perspective of an embodiment of an atmospheric pressure low-temperature plasma spiral jet device of the present invention; Figure 5 This is a longitudinal cross-sectional view of another embodiment of an atmospheric pressure low-temperature plasma spiral jet device of the present invention.

[0038] Markings and corresponding parts names in the accompanying drawings: External electrode 1, external electrode flange 101, contraction cone section 102, expansion cone section 103, throat section 104; Electrode head 2, electrode column 3; Air supply assembly 4, air supply connecting flange 41, groove 410, connecting protruding column 411; spiral column 42, spiral through groove 421, connecting column 422, buffer cavity 423; air supply port 43, buffer groove 44; Air intake assembly 5, cylinder 51, air intake connecting flange 52, air inlet 53, air outlet 54, threaded hole 55; Mounting flange 6; Sealing groove 7. DETAILED DESCRIPTION

[0039] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0040] like Figure 1-Figure 2 As shown, as an embodiment of the present application, an atmospheric pressure low-temperature plasma spiral jet device is provided, including an outer electrode 1, an inner electrode, an air supply component 4 and an air intake component 5. The inner electrode is located inside the outer electrode 1 and is connected to the air intake component 5. The inner electrode includes a coaxially connected electrode head 2 and an electrode column 3. The inner electrode and the outer electrode 1 are respectively connected to the two ends of an existing power supply output.

[0041] The inner electrode and the outer electrode 1 are both made of metal materials such as stainless steel, copper, and nickel; the air supply component 4 is made of insulating material, which uses insulating materials such as polyetheretherketone, polytetrafluoroethylene, alumina ceramics or 316L stainless steel surface sprayed with alumina coating, so that the air supply component 4 as a whole has an insulating effect; the air intake component 5 is made of metal.

[0042] One end of the gas supply component 4 is located inside the outer electrode 1, and the other end of the gas supply component 4 extends out of the outer electrode 1. The gas supply component 4 is located between the inner electrode and the outer electrode 1. The inner electrode and the outer electrode 1 are insulated by the gas supply component 4. A plurality of spiral grooves 421 are provided on the gas supply component 4 along its circumference, and a gas port 43 communicating with the spiral groove 421 is provided at the end of the gas supply component 4.

[0043] The air inlet assembly 5 is provided with an air inlet 53 and an air outlet 54 . The air inlet 53 is connected to the air source pipeline, and the air outlet 54 is connected to the air supply port 43 . The air inlet assembly 5 , the air supply assembly 4 and the outer electrode 1 are connected to each other.

[0044] A plasma generating region is provided on the inner side of the outer electrode 1 . The plasma generating region is located on the side of the gas supply component 4 away from the gas inlet component 5 . One end of the inner electrode is located in the plasma generating region.

[0045] In one embodiment, combined Figure 2-Figure 5 As shown, the air supply assembly 4 includes an air supply connection flange 41 and a spiral column 42. The air supply connection flange 41 and the spiral column 42 are coaxially fixedly connected, as shown in FIG. Figure 3 and Figure 4 As shown, multiple spiral grooves 421 are all opened on the spiral column 42. The spiral grooves 421 are spiral groove structures opened along the outer side of the spiral column 42. Both ends of the groove body pass through the spiral column 42. Figure 2 As shown, the spiral column 42 is inserted into the outer electrode 1 and is close to the inner wall of the outer electrode 1, that is, the diameter of the spiral column 42 matches the inner diameter of the outer electrode 1, and the outer side of the spiral column 42 is close to the outer electrode 1, which can improve the sealing performance of the cooperation between the two and prevent gas leakage, so that the gas can be transported along the spiral groove 421; the gas supply connection flange 41 is located on the outer side of the outer electrode 1, and the gas supply port 43 is opened on the gas supply connection flange 41.

[0046] In one embodiment, Figure 4 As shown, one end of the spiral column 42 is fixedly connected to a connecting column 422, and the connecting column 422 is coaxially connected to the gas supply connecting flange 41. In this embodiment, the bottom of the gas supply connecting flange 41 protrudes outward to form a connecting protrusion 411. The diameter of the connecting protrusion 411 matches the inner diameter of the outer electrode 1. Figure 2 As shown, the connecting boss 411 is inserted into the interior of the outer electrode 1 and matches the interior of the outer electrode 1. The connecting boss 411 can guide and position the installation position of the entire gas supply assembly 4, thereby improving the assembly efficiency and assembly accuracy of the gas supply assembly 4. In this embodiment, the diameter of the connecting column 422 is smaller than the diameter of the spiral column 42, and the connecting column 422 is coaxially connected to the connecting protrusion 411 at the bottom of the gas supply connecting flange 41. In this embodiment, the gas supply assembly composed of the gas supply connecting flange 41 and the spiral column 42 is integrally formed and made of insulating material. Since the diameter of the connecting column 422 is smaller than the spiral column 42, an annular gap is formed between the spiral column 42 and the connecting protrusion 411. In this way, when the spiral column 42 is inserted into the outer electrode 1 and is tightly attached to the outer electrode 1, as shown in FIG. Figure 2 As shown, an annular buffer cavity 423 is formed between the connecting pillar 422 and the inner wall of the outer electrode 1 .

[0047] In one embodiment, the length of the entire air supply component 4 is 30-40 mm, the width of the spiral groove 421 is 2-6 mm, the depth of the spiral groove 421 is 1-5 mm, and the spiral direction of the spiral groove 421 is 30°-60° left or right.

[0048] In one embodiment, Figure 3 and Figure 4 As shown, the air intake assembly 5 includes an air intake connecting flange 52 and a cylinder 51. The cylinder 51 is coaxially connected to the air intake connecting flange 52. In this embodiment, the cylinder 51 and the air intake connecting flange 52 are integrally formed. The cylinder 51 is located in the center of the air intake connecting flange 52 and is hollow inside. The air inlet 53 is located at the top of the cylinder 51. Figure 3 As shown, the gas outlet 54 is opened on the gas inlet connecting flange 52 ; the gas inlet connecting flange 52 and the gas supply connecting flange 41 overlap with each other and are connected to the top of the outer electrode 1 .

[0049] In one embodiment, Figure 2 As shown, the top of the outer electrode 1 is fixedly connected to the outer electrode flange 101. The outer electrode flange 101, the air intake connecting flange 52, and the air supply connecting flange 41 are all provided with a plurality of circumferentially arranged flange holes. The air intake connecting flange 52, the air supply connecting flange 41 and the outer electrode flange 101 overlap with each other and are connected to each other by bolts.

[0050] Seals are provided between the air inlet connection flange 52 and the air supply connection flange 41 and between the air supply connection flange 41 and the outer electrode flange 101. Figure 3 and Figure 4 As shown, an annular sealing groove 7 is provided at the top end of the outer electrode flange 101 and at the bottom end of the air inlet connecting flange 52. The sealing member in this embodiment is an O-ring, and sealing rings are installed in both sealing grooves 7. In this way, when the air inlet connecting flange 52, the air supply connecting flange 41 and the outer electrode flange 101 are overlapped and connected to each other, they can play a sealing role between each other, thereby ensuring the air tightness of the entire device.

[0051] In another embodiment, Figure 5As shown, this embodiment provides another structure in which the air intake connecting flange 52, the air supply connecting flange 41 and the outer electrode 1 are interconnected. In this embodiment, the structure is simplified, and the air supply connecting flange 41 is fixedly connected to the top of the outer electrode 1. The connection method of the air supply connecting flange 41 and the outer electrode 1 is selected according to the material of the air supply connecting flange 41. It can be connected by bonding, mechanical structure connection (clamping, crimping, etc.), welding, etc., and then the air intake connecting flange 52 and the air supply connecting flange 41 are connected to each other by bolts to achieve the connection and fixation of the three.

[0052] In one embodiment, Figure 2 、 Figure 3 and Figure 4 As shown, a buffer groove 44 is provided at the top of the air supply connection flange 41 , and the buffer groove 44 is located in the center of the air supply connection flange 41 , and the air supply port 43 and the air outlet 54 are both communicated with the buffer groove 44 .

[0053] In one embodiment, Figure 4 As shown, there are multiple air outlets 54, and the multiple air outlets 54 are evenly distributed in the center of the air inlet connecting flange 52. Figure 3 As shown, a plurality of air supply ports 43 are provided, and the plurality of air supply ports 43 are evenly distributed circumferentially in the center of the air supply connection flange 41 and located inside the buffer groove 44 .

[0054] In one embodiment, Figure 2 and Figure 3 As shown, a groove 410 is provided at the top of the air supply connecting flange 41, and the flange hole of the air supply connecting flange 41 is located in the groove 410. The air intake connecting flange 52 in the air intake assembly 5 matches the size of the groove 410, and the air intake connecting flange 52 is coaxially embedded in the groove 410 and then connected to the air supply connecting flange 41 by bolts, which can improve the assembly accuracy and quality of the device.

[0055] In one embodiment, the end of the electrode column 3 of the inner electrode away from the electrode head 2 coaxially passes through the gas supply component 4 and is connected to the gas inlet component 5. Specifically: Figure 4 As shown, a threaded hole 55 is provided in the center of the air intake connection flange 52 , and one end of the electrode column 3 away from the electrode head 2 is threadedly connected to the threaded hole 55 in the center of the air intake connection flange 52 , which facilitates installation and disassembly.

[0056] like Figure 2 As shown, the electrode head 2 is threadedly connected to the electrode column 3, and one end of the electrode head 2 is located in the plasma generation area. The electrode head 2 is threadedly connected to the electrode column 3. This makes it easy to fine-tune the length of the electrode head 2 by adjusting the depth of the thread of the electrode head 2. In addition, the threaded connection between the electrode head 2 and the electrode column 3 can actually replace electrode heads of different sizes and materials according to the application conditions.

[0057] In one embodiment, Figure 2 As shown, the plasma generation region is an axisymmetric scaling cavity structure composed of two conical surfaces, that is, the plasma generation region includes a contraction cone section 102, a throat section 104, and an expansion cone section 103. The inner diameter of the lower portion of the outer electrode 1 in the plasma generation region is first contracted to increase the gas flow rate to form the contraction cone section 102, and then the diameter is changed to form the expansion cone section 103, which can effectively increase the plasma area. The contracting cone section 102 and the expanding cone section 103 are connected in series along the axial direction to form a variable cross-section channel. The connection between the contracting cone section 102 and the expanding cone section 103 is the throat 104, that is, the throat 104 is the minimum inner diameter cross-section of the entire plasma generation area, and the area near the throat 104 is the intermediate breakdown zone. The high-frequency pulse breaks down the gas in this area to generate high-density plasma.

[0058] The contraction cone section 102 is close to the gas supply component 4, and the end of the inner electrode away from the gas inlet component 5 extends out of the contraction cone section 102. Specifically, the end of the electrode head 2 of the inner electrode away from the electrode column 3 exceeds the contraction cone section 102, and the spiral airflow coming out of the spiral groove 421 is ionized in the contraction area, and continues to ionize and spirally eject in the area between the electrode head 2 of the inner electrode and the expansion cone section 103 of the outer electrode 1, forming a plasma arc with spiral ejection of plasma.

[0059] In one embodiment, Figure 2 As shown, the half cone angle of the contraction cone section 102 is , the half cone angle of the expansion cone section 103 is , and Set to the same angle or different angles, i.e. The angle size and The angles of can be set to the same angle or different angles; and and The value range of is between 25° and 75°. By adjusting different angle ratios, the area and distance of plasma spray can be adjusted.

[0060] In one embodiment, the distance between the contraction cone section 102 in the outer electrode 1 and the inner electrode can be adjusted by using inner electrodes of different diameters, and the diameter range of the inner electrode is 1-5 mm.

[0061] In one embodiment, the distance that the end of the electrode head 2 of the inner electrode extends beyond the contraction cone section 102 of the outer electrode 1 can be effectively adjusted by the connection thread between the electrode head 2 and the electrode column 3 and the screwing depth of the thread, and the adjustment distance is 0-15 mm.

[0062] According to the application conditions, the distance between the inner electrode and the outer electrode 1 can be fine-tuned by adjusting the screw thread depth between the electrode head 2 and the electrode column 3. The distance between the inner electrode and the outer electrode 1 can also be adjusted by replacing the electrode head 2 of different lengths.

[0063] In one embodiment, Figure 1 As shown, a mounting flange 6 is coaxially connected to the outside of the outer electrode 1, and can be connected to the downstream system through the mounting flange 6. For example, if it is necessary to collect the substances produced by the reaction, the mounting flange 6 can be connected to the reaction chamber, or when the exhaust gas is toxic and harmful and needs to be discharged safely, the mounting flange 6 can be connected to the exhaust treatment system.

[0064] Working principle of the present invention: The working gas forms a rotating airflow through the spiral groove 421 in the gas supply component 4, and is ionized by high-voltage breakdown in the double-conical plasma generation area of ​​the axisymmetric scaling cavity structure, generating a low-temperature (non-equilibrium) plasma spiral jet containing atoms, ions and free radicals, which acts on the surface of the material to achieve material processing or cleaning of contaminants on the material surface, and can also be used for material modification.

[0065] In the present invention, the gas inlet assembly 5 is made of metal, and the electrode column 3 of the inner electrode is threadedly connected to the gas inlet connection flange 52 of the gas inlet assembly 5. Therefore, by applying a plasma generating power source, such as a pulsed high-frequency pulse power source, to the gas inlet assembly 5, a plasma rotating jet can be generated in the plasma generation region between the electrode head 2 and the outer electrode 1. The single-point plasma generated relative to the axis is generated. This structure of the present invention makes the plasma generation efficiency higher and the treatment surface area can be significantly increased. In practice, the power source is suitable for a DC power source or a high-frequency pulse power source, that is, the device can be used as a cathode / anode discharge jet or as a non-polar electrode discharge jet.

[0066] DC or high-frequency pulse non-polarity breakdown: It can be flexibly applied to DC high voltage and DC high-voltage breakdown, and adopts traditional cathode / anode; when high-frequency pulse is selected, the traditional cathode / anode is cancelled, and high-frequency pulse is used to achieve efficient ionization in the middle area of ​​the double-cone plasma generation area.

[0067] Free radical generation technology: spiral gas supply combined with different working gases or air to generate highly active particle types in a targeted manner.

[0068] Adaptive spiral plasma jet without external drive: spiral gas supply combined with airflow compression-ionization-expansion is used to effectively form a spiral uniform plasma, effectively expanding the plasma action area.

[0069] In the present invention, the spiral jet temperature is controlled within the range of 50°C to 350°C by adjusting key control parameters such as gas flow rate (2-10 L / min) and discharge parameters. This achieves low-temperature control (jet temperature 50°C to 350°C) and avoids high-temperature decomposition of the generated material.

[0070] The present invention does not require mechanical drive, and achieves large-area uniform spiral injection through gas dynamic design (spiral groove + plasma generation zone with axisymmetric scaling cavity structure). The use of spiral gas supply to form a plasma rotating arc has high plasma generation efficiency, and the plasma treatment area can be increased without the need for a drive mechanism, and the uniformity is improved. The entire device has no drive mechanism, so the structure is simple, easy to assemble, convenient to adjust, and low in cost. By replacing the electrode head 2, it can meet different discharge conditions.

[0071] The invention is compatible with various gases, generating highly reactive atoms, ions, and free radicals that can be used to efficiently decompose solid compounds. The gas free radicals can effectively decompose specific contaminants on the surface of materials or solid materials.

[0072] The present invention can be applied to the surface treatment of other materials (e.g., surface modification of polymer materials, decontamination of cut surfaces of nuclear fuel rods, etc.); the technology can be transferred to ozone generators or VOC waste gas treatment equipment.

[0073] It should be noted that the above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An atmospheric pressure low temperature plasma spiral jet device, characterized in that: It includes an outer electrode, an inner electrode, an air supply assembly and an air intake assembly, wherein the inner electrode is located inside the outer electrode and connected to the air intake assembly; One end of the gas supply assembly is located inside the outer electrode, and the other end of the gas supply assembly extends out of the outer electrode. The gas supply assembly is located between the inner electrode and the outer electrode, and the inner electrode and the outer electrode are insulated by the gas supply assembly. The gas supply assembly is provided with a plurality of spiral grooves along its circumference, and an end of the gas supply assembly is provided with a gas supply port communicating with the spiral grooves. The air inlet assembly is provided with an air inlet and an air outlet, the air inlet is connected to the air source pipeline, and the air outlet is connected to the air supply port; the air inlet assembly, the air supply assembly and the outer electrode are connected to each other; A plasma generating region is provided on the inner side of the outer electrode. The plasma generating region is located on a side of the gas supply component away from the gas inlet component. One end of the inner electrode is located in the plasma generating region.

2. The atmospheric pressure low temperature plasma spiral jet device according to claim 1, characterized in that: The gas supply assembly includes a gas supply connecting flange and a spiral column. The gas supply connecting flange is coaxially fixedly connected to the spiral column. Multiple spiral grooves are opened on the spiral column. The spiral column is inserted into the interior of the outer electrode and is close to the inner wall of the outer electrode; the gas supply connecting flange is located on the outside of the outer electrode, and the gas supply port is opened on the gas supply connecting flange.

3. The atmospheric pressure low temperature plasma spiral jet device according to claim 2, characterized in that: One end of the spiral column is fixedly connected to a connecting column, which is coaxially connected to the gas supply connecting flange. The diameter of the connecting column is smaller than that of the spiral column, and an annular buffer cavity is formed between the connecting column and the inner wall of the outer electrode.

4. The atmospheric pressure low temperature plasma spiral jet device according to claim 2, characterized in that: The bottom of the gas supply connection flange protrudes outward to form a connection boss, and the connection boss is inserted into the interior of the outer electrode.

5. The atmospheric pressure low temperature plasma spiral jet device according to claim 2, characterized in that: A buffer groove is provided at the top of the air supply connection flange, and the air supply port and the air outlet are both communicated with the buffer groove.

6. The atmospheric pressure low temperature plasma spiral jet device according to claim 2, characterized in that: The air intake assembly includes an air intake connecting flange and a cylinder, the cylinder is connected to the air intake connecting flange, the air inlet is located at the top of the cylinder, and the air outlet is opened on the air intake connecting flange; the air intake connecting flange and the air supply connecting flange overlap with each other and are connected to the top of the outer electrode.

7. The atmospheric pressure low temperature plasma spiral jet device according to claim 6, characterized in that: The top of the outer electrode is fixedly connected to an outer electrode flange, the air intake connecting flange, the air supply connecting flange and the outer electrode flange are connected to each other, and seals are provided between the air intake connecting flange and the air supply connecting flange and between the air supply connecting flange and the outer electrode flange.

8. The atmospheric pressure low temperature plasma spiral jet device according to claim 1, characterized in that: The inner electrode includes a coaxially connected electrode head and an electrode column. One end of the electrode column away from the electrode head coaxially passes through the gas supply component and is connected to the gas inlet component. The electrode head is threadedly connected to the electrode column. One end of the electrode head is located in the plasma generation area.

9. The atmospheric pressure low-temperature plasma spiral jet device according to any one of claims 1 to 8, characterized in that: The plasma generation region is an axisymmetric scaling cavity structure composed of two conical surfaces. The plasma generation region includes a contracting cone section, a throat, and an expanding cone section. The contracting cone section and the expanding cone section are connected in series along the axial direction to form a variable cross-section channel. The connection between the contracting cone section and the expanding cone section is the throat. The contracting cone section is close to the gas supply assembly, and the end of the inner electrode away from the gas inlet assembly extends out of the contracting cone section.

10. The atmospheric pressure low-temperature plasma spiral jet device according to claim 9, characterized in that: The half cone angle of the contraction cone section is , the semi-cone angle of the expansion cone segment is , and Set to the same angle or different angles, and and The value range is between 25° and 75°.

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