A microwave atmospheric pressure plasma jet array based on power divider

Abstract

This invention discloses a microwave atmospheric pressure plasma jet array based on a power divider, relating to the field of microwave atmospheric pressure plasma. It includes an outer cavity and an upper cavity disposed at the upper end of the outer cavity, with a metal cover plate at the upper end of the upper cavity. An inner conductor is disposed inside the outer cavity. This microwave atmospheric pressure plasma jet array based on a power divider utilizes microwave low-temperature plasma to enhance the excitation, ionization, and dissociation processes of gas molecules, resulting in a greater number of excited substate atoms. Its ionization and dissociation of gases are an order of magnitude higher than other types of plasma (such as radio frequency electric field plasma). The plasma has high density, high ionization degree, high energy, and strong activity, making it easier to initiate or trigger related physical and chemical reactions. Therefore, it is more efficient in medical applications that rely on the active components of plasma. Applying this plasma beam to a petri dish containing bacteria or a skin wound can kill bacteria, achieving a sterilization effect.

Description

Technical Field

[0001] This invention relates to the field of microwave atmospheric pressure plasma technology, specifically to a microwave atmospheric pressure plasma jet array based on a power divider. Background Technology

[0002] In recent years, research on microwave atmospheric pressure plasma has become increasingly popular, with considerable application value. It has been applied in fields such as biomedicine, materials processing, agricultural production, and pollution reduction.

[0003] In existing technologies, the processing area of ​​a single jet unit under normal pressure is generally small, which cannot meet the requirements of users for efficient, fast, and large-area processing in practical applications.

[0004] To overcome the above shortcomings, a prior art Chinese patent (publication number CN112996209B) discloses a structure and array structure for microwave-excited atmospheric pressure plasma jets. The aim is to provide an electrode-free, low-cost, and easily processed structure for exciting plasma, avoiding secondary pollution of the excited plasma. The structure includes: a coaxial connector; an excitation structure comprising: a feed transmission line structure, a first metal layer, a dielectric substrate layer, and a second metal layer; the first metal layer is connected to the inner conductor of the coaxial connector via the feed transmission line structure, and the second metal layer is connected to the outer conductor of the coaxial connector; multiple metal vias are arranged along the length of the substrate, connecting the first and second metal layers, and the metal vias enclose a dielectric substrate layer region; a quartz tube is inserted into a through-hole in the substrate; first and second metal rings are located outside the quartz tube and are connected to the first and second metal layers, respectively; the coaxial connector transmits microwave signals to the dielectric substrate layer, and the metal vias confine the microwave signals within the dielectric substrate layer region to excite the gas inside the quartz tube into plasma.

[0005] To overcome the above shortcomings, a prior art Chinese patent (publication number CN119155875A) discloses an atmospheric pressure microwave plasma jet device, including an outer conductor, an inner conductor coaxially arranged inside the outer conductor, a nozzle threadedly connected to the bottom end of the outer conductor, a pin at the end of an RF connector connected to the inner conductor via a connecting conductor, a gas pipe connector threadedly connected to the outer conductor, a short-circuit plug threadedly connected to the top end of the outer conductor, a short-circuit reflective surface at the bottom of a connector installed inside the outer conductor, and a gas guide ring nested on the inner conductor and located between the RF connector and the gas pipe connector. This device achieves a stable atmospheric pressure microwave plasma jet without requiring a complex control module to adjust the system's impedance matching, resulting in a more stable gas flow state and avoiding interference with the plasma at the outlet. Furthermore, the short-circuit reflective surface is designed to be threaded up and down, allowing for fine-tuning of the short-circuit reflective surface to achieve impedance matching.

[0006] While existing technologies can overcome the shortcomings mentioned above, other problems still exist in their operation, such as: the area of ​​microwave atmospheric pressure plasma discharge is small, which is not conducive to user operation; at the same time, due to external factors, the discharge is prone to unevenness, and the energy utilization rate is not high. Summary of the Invention

[0007] The purpose of this invention is to provide a microwave atmospheric pressure plasma jet array based on a power divider, in order to solve the problems mentioned in the background art, such as the small area of ​​microwave atmospheric pressure plasma discharge, which is not conducive to user operation, and the uneven discharge caused by external factors during discharge, as well as the low energy utilization rate.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a microwave atmospheric pressure plasma jet array based on a power divider, comprising an outer cavity and an upper cavity disposed at the upper end of the outer cavity, wherein a metal cover plate is disposed at the upper end of the upper cavity;

[0009] An inner conductor is provided inside the outer cavity, and the surface of the inner conductor is located between the outer cavity and the upper cavity. A gap is provided between the outer cavity and the inner conductor. An RF connector is provided on the outside of the inner conductor, and the RF connector is "N" type.

[0010] The upper end of the radio frequency connector is provided with a coaxial body through the mounting head, and a microwave atmospheric pressure plasma jet unit is provided inside the coaxial body. The microwave atmospheric pressure plasma jet unit is provided with a conductor post, and the conductor post is embedded inside the coaxial body.

[0011] Furthermore, a microwave source is provided at the lower end of the outer cavity, and the upper end of the microwave source is connected to the inner conductor. The outer side of the inner conductor is fixedly installed on the inner side of the outer cavity and the upper cavity through a supporting medium.

[0012] Furthermore, the inner conductor has the shape of a stepped impedance transformation structure with varying diameters, and an isolation dielectric plate is disposed inside the upper cavity, with the conductor probe of the isolation dielectric plate embedded inside the inner conductor.

[0013] Furthermore, the lower end of the coaxial body is connected to the mounting head through a coaxial connecting end, and air guide holes are provided on the left and right sides of the coaxial body, and working medium is provided inside the air guide holes, and the lower end of the working medium is connected to the gas cylinder.

[0014] Furthermore, the upper end of the coaxial body is provided with an open Teflon layer, and a top rotating cap is threaded onto the upper end of the coaxial body.

[0015] Furthermore, the upper end of the conductor post is provided with a discharge tip, and the upper end of the discharge tip is provided with a dielectric layer. The middle end of the conductor post penetrates the interior of the perforated Teflon layer, and the lower end of the conductor post is connected to the upper end of the mounting head.

[0016] Furthermore, a servo motor is fixedly installed on the upper end of the metal cover plate, and a first bevel gear is fixedly installed on the output end of the servo motor. A second bevel gear is meshed on the lower end of the first bevel gear, and a threaded screw is fixedly installed on the outer side of the second bevel gear.

[0017] Furthermore, the left and right ends of the threaded screw are rotatably mounted on the upper end of the metal cover plate via a horizontal plate. The surface of the threaded screw is threaded with movable paddles, and the front and rear ends of the movable paddles are through-mounted with limit guide rods. The left and right ends of the limit guide rods are fixedly mounted on the inner side of the horizontal plate.

[0018] Furthermore, a column plate is fixedly installed on the upper end of the metal cover plate, and a rotating rod is rotatably installed on the upper end of the column plate. A contact plate is fixedly installed on the middle end of the rotating rod, and a sealing adjustment block is sleeved inside the contact plate. The lower end of the sealing adjustment block is rotatably installed on the upper end of the movable lever.

[0019] Furthermore, a grooved positioning plate is fixedly installed on the inner side of the coaxial body, and a striking protrusion plate is slidably connected to the inner side of the grooved positioning plate. Vibration springs are provided between the front and rear ends of the striking protrusion plate and the inner side of the coaxial body, and the inner side of the striking protrusion plate corresponds to the contact plate.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. Microwave low-temperature plasma can further increase the excitation, ionization, and dissociation processes of gas molecules, resulting in more excited substate atoms. Its ionization and dissociation of gases are an order of magnitude higher than other types of plasma (such as radio frequency electric field plasma). The plasma has high density, high degree of ionization, high energy, and strong activity, making it easier to initiate or trigger related physical and chemical reactions. Therefore, it is more efficient in medical applications that rely on plasma active components. By applying the plasma beam to a petri dish containing bacteria or a skin wound, the bacteria can be killed, achieving a sterilization effect.

[0022] 2. This structure is compact, small, portable, easy to assemble and mass-produce. The design of the power divider and its isolation structure ensures that the properties of each plasma jet are consistent. The discharge tip of the conductor in the jet unit is detachable, and the appropriate discharge tip can be replaced according to the frequency of the microwave source. An open-pore Teflon layer is set near the upper part between the conductor column and the coaxial body to help constrain the airflow and stabilize the airflow to a certain extent, making the airflow at the tip more stable, so that the plasma beam can be output stably. When the plasma jet is applied to the plate to be treated, or at a certain distance from the plate, the plasma cleans the surface of the plate through physical and chemical action, achieving a good adhesion effect and facilitating bonding.

[0023] 3. When the device is working, the servo motor is started. The start of the servo motor, through the meshing of the first and second bevel gears at its output end, causes the second bevel gear to drive the threaded screw to rotate. As the threaded screw rotates inside the horizontal plate, it drives the movable block connected to its surface threaded connection. Limited by the guide rod, the movable block moves left and right with the rotation of the threaded screw. During this movement, the movable block drives the upper rotating sealing adjustment block, which pulls the outer contact plate. With the rotating rod, the contact plate rotates along the column plate. Therefore, as the movable block moves, the upper end of the contact plate contacts the striking protrusion plate. After being pressed by the contact plate, the striking protrusion plate strikes the coaxial body along the groove positioning plate. The vibration spring enhances the striking effect, ensuring vibration efficiency and preventing blockage. This prevents internal blockage due to impurities when outputting waveforms within the coaxial body, ensuring the device's efficiency and preventing it from becoming unusable due to impurities. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention;

[0025] Figure 2 This is a schematic diagram of the structure of the present invention from a bottom view;

[0026] Figure 3 This is a three-dimensional structural diagram of the upper cavity of the present invention viewed from below;

[0027] Figure 4 This is a frontal sectional view of the three-dimensional structure of the present invention;

[0028] Figure 5 This is a schematic diagram of the three-dimensional structure of the outer cavity and the upper cavity of the present invention.

[0029] Figure 6 This is a schematic diagram of the three-dimensional structure of the coaxial main body of the present invention;

[0030] Figure 7 This is a side sectional view of the three-dimensional structure of the coaxial main body of the present invention;

[0031] Figure 8 This is a schematic diagram of the three-dimensional structure of the servo motor of the present invention;

[0032] Figure 9 For the present invention Figure 8 Enlarged structural diagram at point A in the middle;

[0033] Figure 10 This is a bottom-view three-dimensional structural diagram of the threaded lead screw of the present invention;

[0034] Figure 11 This is a schematic diagram of the three-dimensional structure of the groove positioning plate of the present invention.

[0035] In the diagram: 1. Outer cavity; 2. Upper cavity; 3. Metal cover plate; 4. Microwave source; 5. Inner conductor; 6. Supporting medium; 7. RF connector; 8. Isolation medium plate; 9. Mounting head; 10. Coaxial body; 11. Vent hole; 12. Working fluid; 13. Top rotating cover; 14. Perforated Teflon layer; 15. Conductor column; 16. Discharge tip; 17. Dielectric layer; 18. Servo motor; 19. First bevel gear; 20. Second bevel gear; 21. Threaded screw; 22. Horizontal plate; 23. Limiting guide rod; 24. Column plate; 25. Movable lever; 26. Sealing adjustment block; 27. Rotating rod; 28. Contact plate; 29. ​​Groove positioning plate; 30. Striking protrusion plate; 31. Vibration spring. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1: As Figures 1-5The technical solution shown is a microwave atmospheric pressure plasma jet array based on a power divider. To address the problems of small discharge area in microwave atmospheric pressure plasma, which is inconvenient for users, uneven discharge due to external factors, and low energy utilization, the solution discloses: an outer cavity 1 and an upper cavity 2 located at the upper end of the outer cavity 1. A metal cover 3 is located at the upper end of the upper cavity 2. An inner conductor 5 is located inside the outer cavity 1, with its surface positioned between the outer cavity 1 and the upper cavity 2. A gap exists between the outer cavity 1 and the inner conductor 5. An RF connector 7, in an "N" shape, is located on the outer side of the inner conductor 5. A coaxial body 10 is located at the upper end of the RF connector 7 via a mounting head 9. A microwave atmospheric pressure plasma jet unit is located inside the coaxial body 10, and the microwave atmospheric pressure plasma jet unit has conductor posts 15 embedded within the coaxial body 10. A microwave source 4 is installed at the lower end of cavity 1, and the upper end of microwave source 4 is connected to inner conductor 5. The outer side of inner conductor 5 is fixedly installed on the inner side of outer cavity 1 and upper cavity 2 through support medium 6. The inner conductor 5 is a stepped impedance transformation structure with different diameters. An isolation medium plate 8 is installed inside upper cavity 2, and the conductor probe of isolation medium plate 8 is embedded inside inner conductor 5. The lower end of coaxial body 10 is connected to mounting head 9 through coaxial connection end, and conductive openings are provided on the left and right sides of coaxial body 10. The gas vent 11 has a working medium 12 inside, and the lower end of the working medium 12 is connected to the gas cylinder. The upper end of the coaxial body 10 has an open Teflon layer 14 inside, and the upper end of the coaxial body 10 is threaded with a top rotating cap 13. The upper end of the conductor post 15 has a discharge tip 16, and the upper end of the discharge tip 16 has a dielectric layer 17. The middle end of the conductor post 15 penetrates the interior of the open Teflon layer 14, and the lower end of the conductor post 15 is connected to the upper end of the mounting head 9.

[0038] Connect the microwave source 4 at the lower end of the device to the power divider, and then inject the working fluid 12 through the two gas guide holes 11. Turn on the microwave source 4, and the microwave energy is evenly distributed to each plasma jet array unit through the power divider and focused at the annular slit at the upper end of the device, making the electric field intensity at this point very high. Adjust the output power of the microwave source 4, and when it reaches a certain value, the electric field intensity at the tip annular slit breaks down the nearby gas, generating plasma. Because the device uses a gradient structure to excite the plasma, the required excitation microwave power is low, so the plasma temperature within the electromagnetic wave is low. The plasma jets of multiple jet units can handle a large area. The design of the power divider and the isolation structure in the outer cavity 1 and the upper cavity 2 ensures that the properties of each plasma jet are consistent. The discharge tip 16 of the jet unit conductor post 15 is detachable, and the appropriate discharge tip 16 can be replaced according to the frequency of the microwave source 4. An open-pore Teflon layer 14 is set near the upper part between the conductor post 15 and the coaxial body 10 to help constrain the airflow and stabilize the airflow to a certain extent, making the airflow at the tip more stable, thereby enabling the plasma beam to be output stably.

[0039] Example 2: Figures 1-7 The technical solution shown, based on Embodiment 1, discloses the following to address the problem of blockage and unusability: a servo motor 18 is fixedly mounted on the upper end of the metal cover plate 3, and a first bevel gear 19 is fixedly mounted on the output end of the servo motor 18. A second bevel gear 20 is meshed on the lower end of the first bevel gear 19, and a threaded screw 21 is fixedly mounted on the outer side of the second bevel gear 20. The left and right ends of the threaded screw 21 are rotatably mounted on the upper end of the metal cover plate 3 via a horizontal plate 22. A movable lever 25 is threaded onto the surface of the threaded screw 21, and a limit guide rod 23 is installed through the front and rear ends of the movable lever 25. The left and right ends of the limit guide rod 23 are fixedly mounted on the metal cover plate 3. A column plate 24 is fixedly installed on the upper end of the metal cover plate 3, and a rotating rod 27 is rotatably installed on the upper end of the column plate 24. A contact plate 28 is fixedly installed on the middle end of the rotating rod 27. A sealing adjustment block 26 is sleeved inside the contact plate 28. The lower end of the sealing adjustment block 26 is rotatably installed on the upper end of the movable lever 25. A groove positioning plate 29 is fixedly installed on the inner side of the coaxial body 10. A striking protrusion plate 30 is slidably connected to the inner side of the groove positioning plate 29. A vibration spring 31 is provided between the front and rear ends of the striking protrusion plate 30 and the inner side of the coaxial body 10. The inner side of the striking protrusion plate 30 corresponds to the contact plate 28.

[0040] When the device is working, the servo motor 18 is started. The start of the servo motor 18, through the meshing of the first bevel gear 19 and the second bevel gear 20 at its output end, causes the second bevel gear 20 to drive the threaded screw 21 to rotate. When the threaded screw 21 rotates inside the horizontal plate 22, it drives the movable lever 25 connected to its surface threadedly. Under the limitation of the guide rod 23, the movable lever 25 moves left and right as the threaded screw 21 rotates. When the movable lever 25 moves, it drives the upper rotating sealing adjustment block 26, which pulls the outer connecting... The contact plate 28, under the setting of the rotating rod 27, can rotate along the column plate 24. Therefore, with the movement of the movable toggle block 25, under the movement of the sealing adjustment block 26, the upper end of the contact plate 28 is driven to contact the striking protrusion plate 30. After being squeezed by the contact plate 28, the striking protrusion plate 30 strikes the coaxial body 10 along the groove positioning plate 29. With the setting of the vibration spring 31, the striking effect can be improved, the vibration efficiency can be guaranteed, and the anti-blocking effect can be achieved. This avoids the internal blockage caused by impurities when the output wave rate is output inside the coaxial body 10, ensuring the efficiency of the device and preventing the device from becoming unusable due to impurities.

[0041] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A microwave atmospheric pressure plasma jet array based on a power divider, comprising an outer cavity (1) and an upper cavity (2) disposed at the upper end of the outer cavity (1), wherein a metal cover plate (3) is disposed at the upper end of the upper cavity (2). Its features are: The outer cavity (1) is provided with an inner conductor (5), and the surface of the inner conductor (5) is provided between the outer cavity (1) and the upper cavity (2), and a gap is provided between the outer cavity (1) and the inner conductor (5). The outer side of the inner conductor (5) is provided with a radio frequency connector (7), and the radio frequency connector (7) is "N" type. The upper end of the radio frequency connector (7) is provided with a coaxial body (10) through the mounting head (9), and a microwave atmospheric pressure plasma jet unit is provided inside the coaxial body (10), and the microwave atmospheric pressure plasma jet unit is provided with a conductor post (15), and the conductor post (15) is embedded inside the coaxial body (10). A microwave source (4) is provided at the lower end of the outer cavity (1), and the upper end of the microwave source (4) is connected to the inner conductor (5); The inner conductor (5) is a stepped impedance transformation structure with different diameters. An isolation dielectric plate (8) is provided inside the upper cavity (2), and the conductor probe of the isolation dielectric plate (8) is embedded inside the inner conductor (5). A servo motor (18) is fixedly installed on the upper end of the metal cover plate (3), and a first bevel gear (19) is fixedly installed on the output end of the servo motor (18), and a second bevel gear (20) is meshed on the lower end of the first bevel gear (19), and a threaded screw (21) is fixedly installed on the outer side of the second bevel gear (20). The left and right ends of the threaded screw (21) are rotatably mounted on the upper end of the metal cover plate (3) via the horizontal plate (22). The threaded screw (21) is threaded with a movable paddle (25), and the front and rear ends of the movable paddle (25) are through-mounted with a limit guide rod (23), and the left and right ends of the limit guide rod (23) are fixedly mounted on the inner side of the horizontal plate (22). The upper end of the metal cover plate (3) is fixedly installed with a column plate (24), and the upper end of the column plate (24) is rotatably installed with a rotating rod (27), and the middle end of the rotating rod (27) is fixedly installed with a contact plate (28), and a sealing adjustment block (26) is sleeved inside the contact plate (28), and the lower end of the sealing adjustment block (26) is rotatably installed on the upper end of the movable lever block (25); A groove positioning plate (29) is fixedly installed on the inner side of the coaxial body (10), and a striking protrusion plate (30) is slidably connected to the inner side of the groove positioning plate (29). Vibration springs (31) are provided between the front and rear ends of the striking protrusion plate (30) and the inner side of the coaxial body (10), and the inner side of the striking protrusion plate (30) corresponds to the contact plate (28).

2. The microwave atmospheric pressure plasma jet array based on a power divider according to claim 1, characterized in that: The outer side of the inner conductor (5) is fixedly installed on the inner side of the outer cavity (1) and the upper cavity (2) by a support medium (6).

3. The microwave atmospheric pressure plasma jet array based on a power divider according to claim 1, characterized in that: The lower end of the coaxial body (10) is connected to the mounting head (9) through the coaxial connection end, and air guide holes (11) are provided on the left and right sides of the coaxial body (10), and working medium (12) is provided inside the air guide hole (11), and the lower end of the working medium (12) is connected to the gas cylinder.

4. A microwave atmospheric pressure plasma jet array based on a power divider according to claim 3, characterized in that: The coaxial body (10) has an open Teflon layer (14) inside its upper end, and a top rotating cover (13) is threaded onto the upper end of the coaxial body (10).

5. A microwave atmospheric pressure plasma jet array based on a power divider according to claim 4, characterized in that: The upper end of the conductor post (15) is provided with a discharge tip (16), and the upper end of the discharge tip (16) is provided with a dielectric layer (17). The middle end of the conductor post (15) penetrates the interior of the perforated Teflon layer (14), and the lower end of the conductor post (15) is connected to the upper end of the mounting head (9).

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