Plasma generating device

Abstract

This utility model relates to the field of air purification technology and discloses a plasma generating device. The plasma generating device of this utility model includes: an inner electrode; an insulating layer surrounding the inner electrode, with the outer periphery of the inner electrode in contact with the inner periphery of the insulating layer; and an outer electrode disposed outside the insulating layer, with a hollowed-out area on the outer electrode. In this embodiment of the plasma generating device, a gapless or micro-gap structure is formed between the inner electrode and the insulating layer. During discharge, the hollowed-out area on the outer electrode can replace the air gap between the inner electrode and the insulating layer to generate discharge, thereby avoiding the problems of uneven electric field distribution, excessively high local electric field, and increased corona initiation voltage caused by excessively large air gaps. This overcomes the problems in related technologies where the size of the air gap is difficult to control, easily resulting in filamentary discharge, or uneven electric field distribution leading to excessively high local voltage and excessively high corona initiation voltage.

Description

Technical Field

[0001] This utility model relates to the field of air purification technology, specifically to a plasma generating device. Background Technology

[0002] Dielectric barrier discharge (DBD) is a non-equilibrium gas discharge that occurs under the barrier of an insulating dielectric. It is widely used in fields such as low-temperature plasma generation, materials processing, and environmental protection. In related technologies, plasma generators using the DBD principle include an inner electrode 1', an insulating layer 2' surrounding the inner electrode 1', and an outer electrode 4' surrounding the insulating layer 2'. An air gap 5' is formed between the inner electrode 1' and the insulating layer 2'.

[0003] However, the size of the air gap is difficult to control. If the air gap is too small, it is easy to generate filamentary discharge. When the air gap 5' is too large, it is easy to cause uneven electric field distribution, resulting in excessively high local electric field and excessively high corona voltage. Utility Model Content

[0004] In view of this, the present invention provides a plasma generating device to solve the problems in the related technology, such as the difficulty in controlling the size of the air gap, which easily leads to filamentary discharge, or uneven electric field distribution, which causes excessively high local voltage and excessively high corona initiation voltage.

[0005] This utility model provides a plasma generating device, comprising:

[0006] Internal electrode;

[0007] An insulating layer is provided around the inner electrode, and the outer periphery of the inner electrode is in contact with the inner periphery of the insulating layer;

[0008] The outer electrode is located outside the insulating layer and has a hollowed-out area.

[0009] Beneficial effects: With this configuration, the plasma generating device of this utility model embodiment forms a gapless or micro-gap structure between the inner electrode and the insulating layer.

[0010] During the discharge process, the hollow area on the outer electrode can replace the air gap between the inner electrode and the insulating layer to discharge, thus avoiding the problems caused by the formation of an air gap between the inner electrode and the insulating layer. That is, when the size of the air gap is too large, it is easy to cause uneven electric field distribution, resulting in excessively high local electric field and increased corona voltage; when the air gap changes, it is easy to cause unstable discharge, resulting in problems such as affecting the long-term reliability of the equipment.

[0011] Furthermore, since the plasma generating device of this utility model eliminates the air gap between the inner electrode and the insulating layer, it avoids oxidation, corrosion, and even rust caused by the inner electrode being exposed to the plasma environment. This prevents the increase in the corona voltage of the plasma generating device due to rust, and improves the current stability of the plasma discharge device, making the discharge more uniform and avoiding local overheating or arcing. It is more suitable for scenarios with long-term continuous use.

[0012] Furthermore, because the plasma generator of this embodiment can optimize the electric field distribution, control the discharge intensity, and reduce local high-temperature areas, the ozone generation of the plasma generator of this embodiment is significantly reduced at the same power, which can improve the safety and environmental protection of the equipment. It is particularly suitable for ozone-sensitive application scenarios such as air purification and medical disinfection.

[0013] Therefore, the plasma generating device of this utility model embodiment can overcome the problems existing in related technologies, such as the difficulty in controlling the size of the air gap, the easy generation of filamentary discharge, or uneven electric field distribution, which can lead to excessively high local voltage and excessively high corona initiation voltage.

[0014] In one alternative embodiment, the internal electrode is a conductive liquid or conductive adhesive infused within an insulating layer.

[0015] Beneficial effects: With this configuration, conductive liquid or conductive adhesive can adaptively fill the grooves and holes on the inner circumference of the insulating layer, thereby integrating the inner electrode with the insulating layer to form an integral electrode structure. This avoids the difficulties in installing the inner electrode into the insulating layer, and may even damage the insulating layer. The operation is simple and convenient.

[0016] In one alternative implementation, the internal electrode includes:

[0017] Electrode body;

[0018] A conductive layer is disposed between the electrode body and the insulating layer, and can fill the gap between the electrode body and the insulating layer.

[0019] Beneficial effects: By using this configuration, the gap between the electrode body and the insulating layer is filled by the conductive layer, thereby forming a gapless or micro-gap structure between the inner electrode and the insulating layer. This avoids the defects that occur when the air gap is too small, such as difficulty in installing the inner electrode into the insulating layer, or even damage to the insulating layer.

[0020] In one embodiment, the conductive layer comprises a conductive liquid infused between the electrode body and the insulating layer.

[0021] Beneficial effects: The conductive liquid has fluidity and can completely fill the gap between the electrode body and the insulating layer, avoiding air gaps caused by poor adhesion between the conductive layer and the electrode body or the insulating layer. It can also adaptively fill grooves and holes on the surface of the electrode body or the insulating layer. The process of injecting conductive liquid between the electrode body and the insulating layer is simple and has a low loss rate.

[0022] In one alternative embodiment, the conductive layer includes a conductive coating applied between the electrode body and the insulating layer.

[0023] Beneficial effects: By forming a conductive layer between the electrode body and the insulating layer through the coating process, the thickness of the conductive layer can be precisely controlled, avoiding material waste and eliminating the risk of leakage and volatilization. It is also less likely to cause problems such as freezing and swelling or shrinkage of the conductive layer due to temperature changes, which helps to improve the stability of plasma generator operation.

[0024] In one alternative embodiment, the conductive layer includes a conductive adhesive filled between the electrode body and the insulating layer.

[0025] Beneficial effects: When the conductive layer includes conductive adhesive filling the space between the electrode body and the insulating layer, the conductive adhesive can initially be a semi-fluid, gel-like, or malleable paste, capable of filling the tiny gaps between the electrode body and the insulating layer.

[0026] After the conductive adhesive is filled between the electrode body and the insulating layer, it is cured using curing conditions adapted to the type of conductive adhesive, so that the conductive layer adheres tightly to the electrode body and the insulating layer.

[0027] When conductive adhesive is used to form a conductive layer, the conductive adhesive is both fluid in its initial state, which can fully fill the tiny gaps between the electrode body and the insulating layer, and can also adhere tightly to the inner electrode and the insulating layer after curing, avoiding air gaps caused by poor adhesion.

[0028] Based on this, the cured conductive adhesive also has a certain degree of elasticity, which can absorb the mechanical stress between the electrode body and the insulating layer through its own deformation when the plasma generator is subjected to vibration, impact or temperature change. This avoids the formation of air gaps between the electrode body and the insulating layer due to rigid contact, thereby making the operation of the plasma generator more stable and helping to extend the service life of the plasma generator.

[0029] Furthermore, the conductive adhesive can become solid after curing, without the risk of volatilization or leakage. Liquid leakage can cause corrosion to the insulation layer or interfere with the discharge performance of the plasma generator.

[0030] In one alternative embodiment, the outer electrode is a spiral electrode surrounding the insulating layer, with a hollowed-out area formed between adjacent turns of the spiral electrode; or,

[0031] The outer electrode is a mesh electrode surrounding the insulating layer, with the mesh openings being open areas; or,

[0032] The external electrode includes multiple conductive rings surrounding the insulating layer, and the multiple conductive rings are electrically connected.

[0033] In one alternative embodiment, the internal electrode is a metal wire, a plated metal, or a non-metallic conductive material.

[0034] In one alternative embodiment, the insulating layer is ceramic, glass, or polymer.

[0035] In one optional embodiment, the diameter of the inner electrode is r1, 0.5mm ≤ r1 ≤ 2mm; and / or,

[0036] The inner diameter of the insulation layer is r2, and the outer diameter of the insulation layer is r3. 0.5mm≤r2≤2.5mm, 0.6mm≤r3≤3.5mm.

[0037] In one optional embodiment, the electrode comprises a conductive metal wire spirally wound around the outside of the insulating layer, the diameter of the conductive metal wire being r4, 0.03mm≤r4≤0.15mm; or,

[0038] The external electrode comprises multiple conductive metal wires spirally wound around the outside of the insulating layer. These conductive metal wires are connected in parallel, and the diameter of each conductive metal wire is r5, where 0.03 mm ≤ r5 ≤ 0.15 mm; or...

[0039] The external electrode is a bundle of carbon fibers spirally wrapped around the outside of the insulating layer.

[0040] Beneficial effects: When the external electrode includes multiple conductive metal wires spirally wrapped around the outside of the insulating layer, the multiple metal wires can form a denser and more uniform electric field distribution outside the insulating layer, and avoid uneven discharge caused by local defects in a single metal wire. It can also prevent the plasma generator from shutting down due to the breakage or failure of a single metal wire, making the operation of the plasma generator more reliable.

[0041] In one alternative embodiment, the plasma generator is an air purification device or a disinfection device. Attached Figure Description

[0042] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of a plasma generating device in related technologies;

[0044] Figure 2 A cross-sectional view of a plasma generator in related technologies at one angle;

[0045] Figure 3 This is a cross-sectional view of a plasma generator in the related technology from another angle.

[0046] Figure 4 This is a cross-sectional view of a plasma generating device according to an embodiment of the present invention at one angle;

[0047] Figure 5 This is a cross-sectional view of a plasma generating device according to an embodiment of the present invention from another angle. The inner electrode and the insulating layer are filled with conductive adhesive.

[0048] Figure 6 for Figure 5 Enlarged diagram of point A in the diagram;

[0049] Figure 7 This is a cross-sectional view of a plasma generating device according to an embodiment of the present invention from another angle. A conductive coating is applied between the inner electrode and the insulating layer.

[0050] Figure 8 The image shows a discharge of a plasma generator in the related technology under operating conditions of 18.2 kHz and 3.8 kV.

[0051] Figure 9 The image shows a discharge of a plasma generator in the related technology under operating conditions of 18.2 kHz and 4.2 kV.

[0052] Figure 10 This is a discharge image of a plasma generator according to an embodiment of the present invention under operating conditions of 18.2 kHz and 3.2 kV.

[0053] Figure 11 This is a discharge image of a plasma generator according to an embodiment of the present invention under operating conditions of 18.2 kHz and 3.8 kV.

[0054] Figure 12 The image shows the discharge of a plasma generator in the newly operational state in the relevant technology.

[0055] Figure 13 The image shows the discharge of a plasma generator in the related technology after 100 hours of operation.

[0056] Figure 14 Photographs of the internal electrodes of a plasma generator in related technologies after 100 hours of operation;

[0057] Figure 15 Photograph of the internal electrodes of the plasma generator according to an embodiment of the present invention after 800 hours of operation;

[0058] Figure 16 The image shows the discharge of the plasma generator according to an embodiment of the present invention after 800 hours of operation.

[0059] Figure 17 The image shows the discharge of the plasma generator according to an embodiment of the present invention under operating conditions of 12 Hz and 4.5 kV.

[0060] Figure 18 The image shows the discharge of the plasma generator according to an embodiment of the present invention under operating frequency of 12 Hz and voltage of 5 kV.

[0061] Figure 19 The image shows the discharge of the plasma generator according to an embodiment of the present invention under operating conditions of 12 Hz and 5.5 kV.

[0062] Figure 20 The image shows the discharge of the plasma generator according to an embodiment of the present invention under operating frequency of 12 Hz and voltage of 6 kV.

[0063] Figure 21 The image shows the discharge of a plasma generator in the related technology under operating conditions of 12 Hz and 3 kV.

[0064] Figure 22 The image shows the discharge of a plasma generator in the related technology under operating conditions of 12 Hz and 5 kV.

[0065] Figure 23 The image shows the discharge of a plasma generator in the related technology under operating conditions of 12 Hz and 6 kV.

[0066] Figure 24 The image shows a discharge of a plasma generator in the related technology under operating conditions of 12 Hz and 6.5 kV.

[0067] Explanation of reference numerals in the attached figures:

[0068] 1. Internal electrode; 101. Electrode body;

[0069] 2. Insulation layer;

[0070] 3. Conductive layer;

[0071] 4. External electrode; 401. Hollowed-out area;

[0072] 1' Internal electrode;

[0073] 2' Insulation layer;

[0074] 4' External electrode;

[0075] 5', Air gap. Detailed Implementation

[0076] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0077] In the description of this application, it should be understood that the terms "inner" and "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0078] like Figures 1 to 3 As shown, dielectric barrier discharge is a non-equilibrium gas discharge that occurs under the obstruction of an insulating medium. In related technologies, a plasma generator that discharges based on the principle of dielectric barrier discharge includes an inner electrode 1', an insulating layer 2' surrounding the inner electrode 1', and an outer electrode 4' located outside the insulating layer 2'. An air gap 5' is formed between the inner electrode 1' and the insulating layer 2'. During the operation of the plasma generator, the discharge is generated within the air gap.

[0079] During long-term operation, the internal electrode 1' (especially the metal wire) is exposed to the plasma environment, which makes it prone to oxidation, corrosion and even rust.

[0080] Corrosion on the electrode surface can alter its conductivity, leading to an increase in the local electric field strength and thus causing an increase in the corona initiation voltage.

[0081] After the corona initiation voltage increases, the plasma generator becomes difficult to maintain a stable discharge state, which seriously affects its purification function and service life.

[0082] In related technologies, after 100 hours of operation, the corona initiation voltage of a plasma generator increases by more than 20%, and its discharge performance decreases significantly.

[0083] Based on this, in related technologies, during the assembly process of a plasma generator, the inner electrode 1' usually needs to be inserted into the tubular insulating layer 2', but this assembly method makes it difficult to control the size of the air gap 5'.

[0084] For example, if the size of the air gap 5' is too small, it can make the process of installing the inner electrode 1' into the insulating layer 2' more difficult, and may even damage the insulating layer 2'.

[0085] When the size of the air gap 5' is large, it is easy to cause uneven electric field distribution, resulting in excessively high local electric field and increased corona initiation voltage;

[0086] Furthermore, changes in the air gap 5' can lead to unstable discharge, affecting the long-term operational reliability of the equipment.

[0087] For example, non-uniformity in the air gap 5' leads to electric field concentration, generating filamentary discharge and increasing ozone levels. Inserted electrodes, due to non-uniformity in the air gap 5', are prone to forming localized areas of electric field concentration. These areas are susceptible to filamentary discharge, which not only reduces discharge efficiency but also impacts and interferes with the power supply system.

[0088] Filament discharge can also lead to localized high temperatures, further exacerbating electrode corrosion and aging of the insulation layer 2'.

[0089] At the same time, filamentary discharge and strong electric fields can also promote ozone generation, which will bring safety hazards and environmental problems in applications such as air purification.

[0090] The following is combined Figures 4 to 24 The following describes embodiments of the present invention.

[0091] According to an embodiment of the present invention, a plasma generating device is provided, comprising an inner electrode 1, an insulating layer 2, and an outer electrode 4.

[0092] The inner electrode 1 can be connected to a power source. An insulating layer 2 surrounds the inner electrode 1, and the outer periphery of the inner electrode 1 is in contact with the inner periphery of the insulating layer 2. An outer electrode 4 is disposed outside the insulating layer 2, and a hollow area 401 is provided on the outer electrode 4.

[0093] With this configuration, the plasma generating device of this utility model embodiment forms a gapless or micro-gap structure between the inner electrode 1 and the insulating layer 2.

[0094] During the discharge process, the hollow area 401 on the outer electrode 4 can replace the air gap between the inner electrode 1 and the insulating layer 2 to discharge, thereby avoiding the problems caused by the formation of an air gap between the inner electrode 1 and the insulating layer 2. That is, when the size of the air gap is too large, it is easy to cause uneven electric field distribution, resulting in excessively high local electric field and increased corona voltage; when the air gap changes, it is easy to cause unstable discharge, resulting in problems such as affecting the long-term reliability of the equipment.

[0095] Furthermore, since the plasma generating device of this utility model eliminates the air gap between the inner electrode 1 and the insulating layer 2, it avoids oxidation, corrosion, or even rusting caused by the inner electrode 1 being exposed to the plasma environment. This prevents the increase in the corona voltage of the plasma generating device due to rusting, and improves the current stability of the plasma discharge device, making the discharge more uniform and avoiding local overheating or arcing. It is more suitable for scenarios of long-term continuous use.

[0096] Furthermore, because the plasma generator of this embodiment can optimize the electric field distribution, control the discharge intensity, and reduce local high-temperature areas, the ozone generation of the plasma generator of this embodiment is significantly reduced at the same power, which can improve the safety and environmental protection of the equipment. It is particularly suitable for ozone-sensitive application scenarios such as air purification and medical disinfection.

[0097] Therefore, the plasma generating device of this utility model embodiment can overcome the problems existing in related technologies, such as the difficulty in controlling the size of the air gap, which can easily cause damage to the insulation layer 2, generate filamentary discharge, or cause uneven electric field distribution, resulting in excessively high local voltage and excessively high corona voltage.

[0098] Among them, micro-gap structures refer to tiny gaps, typically in the micrometer or even nanometer scale, that exist between different objects or different parts of the same object.

[0099] In one embodiment, the inner electrode 1 is used to connect to high voltage, and the outer electrode 4 is used to ground.

[0100] As a variable implementation, the inner electrode 1 is used for grounding, and the outer electrode 4 is used for connecting to high voltage.

[0101] In one variable implementation, the power supply is an AC power supply, and the inner electrode 1 and the outer electrode 4 are respectively connected to one output terminal of the power supply.

[0102] In one embodiment, the inner electrode 1 is a conductive liquid or conductive adhesive poured into the insulating layer 2.

[0103] With this configuration, conductive liquid or conductive adhesive can adaptively fill the grooves and holes on the inner circumference of the insulating layer 2, thereby integrating the inner electrode 1 with the insulating layer 2 to form an integral electrode structure. This avoids the difficulties in installing the inner electrode 1 into the insulating layer 2, and may even damage the insulating layer 2. The operation is simple and convenient.

[0104] In one embodiment, the inner electrode 1 includes an electrode body 101 and a conductive layer 3. The conductive layer 3 is disposed between the electrode body 101 and the insulating layer 2, and is capable of filling the gap between the electrode body 101 and the insulating layer 2.

[0105] With this configuration, the conductive layer 3 fills the gap between the electrode body 101 and the insulating layer 2, thereby forming a gapless or micro-gap structure between the inner electrode 1 and the insulating layer 2. This avoids the defects that occur when the air gap is too small, making it difficult to install the inner electrode 1 into the insulating layer 2, and even potentially damaging the insulating layer 2.

[0106] In one embodiment, the conductivity of the conductive layer 3 is preferably close to or the same as that of the electrode body 101.

[0107] In one embodiment, the conductive layer 3 comprises a conductive liquid infused between the electrode body 101 and the insulating layer 2.

[0108] The conductive liquid has fluidity and can completely fill the gap between the electrode body 101 and the insulating layer 2, avoiding air gaps caused by poor adhesion between the conductive layer 3 and either the electrode body 101 or the insulating layer 2. It can also adaptively fill grooves and holes on the surface of the electrode body 101 or the insulating layer 2. The process of injecting conductive liquid between the electrode body 101 and the insulating layer 2 is simple and has a low loss rate.

[0109] The conductive liquid includes, but is not limited to, inorganic salt solutions, ionic solutions, or electrolyte solutions.

[0110] In one embodiment, such as Figure 7 As shown, the conductive layer 3 includes a conductive coating applied between the electrode body 101 and the insulating layer 2.

[0111] By forming a conductive layer 3 between the electrode body 101 and the insulating layer 2 through a coating process, the thickness of the conductive layer 3 can be precisely controlled, avoiding material waste and eliminating the risk of leakage and volatilization. It is also less likely to cause problems such as freezing expansion or shrinkage of the conductive layer 3 due to temperature changes, which helps to improve the stability of the plasma generator operation.

[0112] The conductive coating is preferably, but not limited to, being applied between the inner electrode 1 and the insulating layer 2 by means of brushing, spraying, or dipping.

[0113] In one embodiment, the conductive layer 3 includes a conductive adhesive filled between the electrode body 101 and the insulating layer 2.

[0114] When the conductive layer 3 includes conductive adhesive filled between the electrode body 101 and the insulating layer 2, the conductive adhesive can initially be a semi-fluid, gel-like, or malleable paste, capable of filling the tiny gaps between the electrode body 101 and the insulating layer 2.

[0115] After the conductive adhesive is filled between the electrode body 101 and the insulating layer 2, the conductive adhesive is cured under curing conditions that are compatible with the type of conductive adhesive, so that the conductive layer 3 is tightly bonded to the electrode body 101 and the insulating layer 2.

[0116] When conductive adhesive is used to form conductive layer 3, the conductive adhesive is both fluid in the initial state, which can fully fill the tiny gap between electrode body 101 and insulating layer 2, and can also adhere tightly to electrode body 101 and insulating layer 2 after curing, avoiding air gaps caused by poor adhesion.

[0117] Based on this, the cured conductive adhesive also has a certain degree of elasticity, which can absorb the mechanical stress between the electrode body 101 and the insulating layer 2 by its own deformation when the plasma generator is subjected to vibration, impact or temperature change, thus avoiding the formation of air gaps between the electrode body 101 and the insulating layer 2 due to rigid contact, thereby making the operation of the plasma generator more stable and helping to extend the service life of the plasma generator.

[0118] Furthermore, the conductive adhesive can become solid after curing, without the risk of volatilization or leakage. Liquid leakage can prevent corrosion of the insulation layer 2 or interference with the discharge performance of the plasma generator.

[0119] Among them, the preferred curing conditions include, but are not limited to, room temperature curing, heat curing, or ultraviolet light curing.

[0120] Among them, the conductive adhesive is preferably, but not limited to, silver paste or carbon-based conductive adhesive.

[0121] In one embodiment, the outer electrode 4 is a spiral electrode surrounding the insulating layer 2, and a hollowed-out region 401 is formed between two adjacent turns of the spiral electrode.

[0122] With this configuration, during the discharge process, the plasma generator can form a discharge on the surface of the insulating layer 2 and between two adjacent spiral electrodes.

[0123] In one embodiment, the outer electrode 4 is a mesh electrode surrounding the insulating layer 2, and the mesh of the mesh electrode is a hollow area 401.

[0124] With this configuration, during the discharge process, the plasma generator can generate a discharge on the surface of the insulating layer 2 and within the mesh of the mesh electrode.

[0125] In one embodiment, the mesh electrode is preferably, but not limited to, a metal mesh woven from conductive wires.

[0126] In one embodiment, the mesh electrode is a perforated metal mesh.

[0127] In one embodiment, the external electrode 4 includes a plurality of conductive rings surrounding the insulating layer 2, and the plurality of conductive rings are electrically connected.

[0128] With this configuration, during the discharge process, the plasma generator can form a discharge on the surface of the insulating layer 2 and between two adjacent conductive rings.

[0129] The conductive connection between multiple conductive rings is preferably, but not limited to, a series or parallel connection.

[0130] In the description of this application, "multiple" means two or more, unless otherwise expressly and specifically defined.

[0131] In one embodiment, the internal electrode 1 is a metal wire, a plated metal, or a non-metallic conductive material.

[0132] In one embodiment, the insulating layer 2 is ceramic, glass, or polymer.

[0133] In one embodiment, the insulating layer 2 is alumina or zirconia ceramic with a dielectric constant between 7 and 10.

[0134] When the dielectric constant of the insulating layer 2 is within the above range, it can effectively prevent the risk of short circuit and leakage, and it is easier to form a stable electric field under the voltage of the electrode operation, thus taking into account both the stability of the electric field and the control of energy consumption.

[0135] In one embodiment, the insulating layer 2 can also be formed by means of coating or electroplating.

[0136] In one embodiment, such as Figure 5 and Figure 6 As shown, the diameter of the inner electrode 1 is r1, 0.5mm≤r1≤2mm.

[0137] In one embodiment, r1 = 0.9 mm.

[0138] In one embodiment, r1 = 0.95 mm.

[0139] The inner diameter of the insulation layer 2 is r2, and the outer diameter of the insulation layer 2 is r3. 0.5mm≤r2≤2.5mm, 0.6mm≤r3≤3.5mm.

[0140] In one embodiment, r2 = 1 mm and r3 = 1.5 mm.

[0141] In one embodiment, r2 = 0.95 mm and r3 = 1.05 mm.

[0142] In one embodiment, the external electrode 4 includes a conductive metal wire spirally wound around the outside of the insulating layer 2, the diameter of the conductive metal wire being r4, 0.03mm≤r4≤0.15mm.

[0143] In one embodiment, the external electrode 4 includes multiple conductive metal wires spirally wound around the outside of the insulating layer 2. The multiple conductive metal wires are connected in parallel with each other, and the diameter of each conductive metal wire is r5, where 0.03mm≤r5≤0.15mm.

[0144] In one embodiment, the metal wire is a tungsten wire, and r5 = 0.05 mm.

[0145] When the external electrode 4 includes multiple conductive metal wires spirally wrapped around the outside of the insulating layer 2, the multiple metal wires can form a denser and more uniform electric field distribution outside the insulating layer 2, and avoid uneven discharge caused by local defects in a single metal wire. It can also prevent the plasma generator from shutting down due to the breakage or failure of a single metal wire, making the operation of the plasma generator more reliable.

[0146] In one embodiment, the external electrode 4 is a carbon fiber bundle spirally wrapped around the insulating layer 2.

[0147] In one embodiment, the carbon fiber bundle comprises 1000 carbon fibers, each with a diameter of 7 μm.

[0148] Experiment 1:

[0149] The applicant recorded the discharge voltage and discharge phenomenon of the plasma generator filled with conductive adhesive in the embodiments of this application and compared it with similar products in related technologies.

[0150] The inner electrode 1 is made of stainless steel wire with a diameter of 0.9 mm, the inner diameter of the insulation layer 2 is 1 mm and the thickness is 0.5 mm, and the outer electrode 4 is a carbon fiber bundle spirally wrapped around the insulation layer 2. Each carbon fiber bundle contains about 1000 fibers, and the diameter of a single carbon fiber is 7 μm.

[0151] The applicant compared the discharge voltage and discharge brightness of the plasma generator in this application with those in related technologies under the same conditions, and recorded the test results as follows:

[0152] Using a Suman AC power supply at a frequency of 18kHz, the discharge parameters were adjusted. A comparison shows that, compared to a single electrode, [the following is an example / detail]. Figure 10 and Figure 11 As shown, with a conductive layer 3 formed between the inner electrode 1 and the insulating layer 2, the corona initiation voltage of the plasma generator is 3.2KV.

[0153] like Figure 8 and Figure 9 As shown, without conductive layer 3, the corona initiation voltage of the plasma generator is 3.8KV, and the corona initiation voltage difference is at least 600V.

[0154] Different insulating layer materials and thicknesses have different effects on corona initiation voltage.

[0155] Experiment 2:

[0156] Figure 12 This is a discharge image of a plasma generator in related technologies just starting up under the conditions of 3.2KV voltage, 10KHZ operating frequency, 170.5MA current, and 31.2W power.

[0157] Figure 13 These are discharge images of a plasma generator in related technologies after 100 hours of operation. Figure 13 It can be seen that the discharge of a single electrode in the plasma generator in the relevant technology weakens significantly after 100 hours of operation, requiring the voltage to be increased to 3.8KV and 10KHZ, and some positions still do not discharge.

[0158] like Figure 14 As shown, the internal electrode 1 of the plasma generator in the related technology showed obvious corrosion on its surface after 100 hours of operation.

[0159] Figure 15 The photograph shows the inner electrode 1 of the plasma generator according to an embodiment of this application after 800 hours of operation. It can be seen that the inner electrode 1 of this embodiment of the application has almost no corrosion.

[0160] Figure 16 These are discharge images of the plasma generator according to an embodiment of this application under conditions of 3.2 kV voltage and 10 kHz operating frequency. Figure 16 As can be seen, the discharge images of the plasma generator in this application embodiment have not changed significantly, indicating that the injection of conductive adhesive can effectively prevent corrosion of the inner electrode 1.

[0161] Experiment 3:

[0162] The applicant recorded the discharge voltage and discharge phenomenon of the plasma generator in which the inner electrode 1 is a conductive liquid in the embodiment of this application, and compared it with the plasma generator in the related art (the scheme of inserting the inner electrode 1 into the insulating layer 2).

[0163] After comparison, such as Figures 17 to 24 As shown, the corona initiation voltage of the plasma generator in this embodiment is much lower than that of plasma generator solutions in related technologies.

[0164] The corona initiation voltage of the plasma generator in this embodiment is 12kHz, 4.5kV;

[0165] The corona initiation voltage of the plasma generator in the related technology is 12kHz, 6.0kV.

[0166] Multiple experimental comparisons show that the corona initiation voltage of the electrodes of the plasma generator in this application embodiment is greatly reduced, and the uniformity and stability of the discharge are better.

[0167] Experiment 4:

[0168] The ozone concentration was compared between two electrode structures: one with conductive sealant between the inner electrode 1 and the insulating layer 2, and the other without conductive sealant.

[0169] It can be concluded that, under the same discharge brightness conditions, the ozone concentration generated by the electrode structure with conductive glue is 30 PPB.

[0170] The ozone concentration generated by the un-glued electrode structure was 48 PPB, indicating that filling the air gaps with conductive adhesive can reduce the ozone concentration generated by discharge.

[0171] The test current graph also shows that the current fluctuations during discharge in the air gap are greater and the discharge is less stable.

[0172] In one embodiment, the plasma generator is an air purification device or a disinfection device.

[0173] In summary, the plasma generating device of this utility model embodiment can overcome the problems existing in related technologies, such as the difficulty in controlling the size of the air gap, which can easily cause damage to the insulation layer 2, generate filamentary discharge, or cause uneven electric field distribution, resulting in excessively high local voltage and excessively high corona voltage.

[0174] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and all such modifications and variations fall within the scope of protection claimed by the present invention.

Claims

1. A plasma generating device, characterized by comprising: include: Internal electrode (1); An insulating layer (2) is disposed around the inner electrode (1), and the outer periphery of the inner electrode (1) is in contact with the inner periphery of the insulating layer (2); An external electrode (4) is disposed outside the insulating layer (2), and a hollow area (401) is provided on the external electrode (4).

2. The plasma generating device of claim 1, wherein, The inner electrode (1) is a conductive liquid or conductive adhesive poured into the insulating layer (2).

3. The plasma generating device of claim 1, wherein The internal electrode (1) includes: Electrode body (101); A conductive layer (3) is disposed between the electrode body (101) and the insulating layer (2), and is capable of filling the gap between the electrode body (101) and the insulating layer (2).

4. The plasma generating device of claim 3, wherein The conductive layer (3) includes a conductive liquid poured between the electrode body (101) and the insulating layer (2).

5. The plasma generating device of claim 3, wherein The conductive layer (3) includes a conductive coating applied between the electrode body (101) and the insulating layer (2).

6. The plasma generating apparatus according to claim 3, characterized in that, The conductive layer (3) includes conductive adhesive filled between the electrode body (101) and the insulating layer (2).

7. The plasma generating device according to any one of claims 1 to 6, characterized in that, The outer electrode (4) is a spiral electrode surrounding the insulating layer (2), and the hollowed-out area (401) is formed between two adjacent turns of the spiral electrode; or, The outer electrode (4) is a mesh electrode surrounding the insulating layer (2), and the mesh openings of the mesh electrode are the hollow areas (401); or, The outer electrode (4) includes a plurality of conductive rings surrounding the insulating layer (2), and the plurality of conductive rings are electrically connected.

8. The plasma generating device according to any one of claims 1 to 6, characterized in that, The internal electrode (1) is a metal wire, a plated metal, or a non-metallic conductive material.

9. The plasma generating device according to any one of claims 1 to 6, characterized in that, The insulating layer (2) is made of ceramic, glass or polymer.

10. The plasma generating device of any one of claims 1 to 6, wherein, The diameter of the inner electrode (1) is r1, 0.5mm ≤ r1 ≤ 2mm; and / or, The inner diameter of the insulating layer (2) is r2, and the outer diameter of the insulating layer (2) is r3, where 0.5mm≤r2≤2.5mm and 0.6mm≤r3≤3.5mm.

11. The plasma generating device of any one of claims 1 to 6, wherein, The external electrode (4) includes a conductive metal wire spirally wound around the outside of the insulating layer (2), the diameter of the conductive metal wire being r4, 0.03mm≤r4≤0.15mm; or, The external electrode (4) comprises multiple conductive metal wires spirally wound around the insulating layer (2), the multiple conductive metal wires being connected in parallel, and the diameter of each conductive metal wire being r5, 0.03mm≤r5≤0.15mm; or, The external electrode (4) is a carbon fiber bundle spirally wrapped around the insulating layer (2).

12. The plasma generating device of any one of claims 1 to 6, wherein, The plasma generator is an air purification device or a disinfection device.

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