Plasma generating device

Abstract

The invention relates to the technical field of air purification, and discloses a plasma generating device, which comprises an inner electrode, an outer electrode and an inner electrode, the insulating layer is arranged outside the inner electrode in a surrounding manner, and the outer periphery of the inner electrode is attached to the inner periphery of the insulating layer; and the outer electrode is arranged outside the insulating layer, and a hollow area is arranged on the outer electrode. According to the plasma generating device provided by the embodiment of the invention, a gapless or micro-gap structure is formed between the inner electrode and the insulating layer, and the hollow area on the outer electrode can replace an air gap between the inner electrode and the insulating layer to discharge in the discharge process, so that the problem that the electric field distribution is not uniform easily when the size of the air gap is too large is avoided; the problems that in the prior art, the size of the air gap is difficult to control, filamentous discharge is prone to being generated, or the electric field distribution is uneven, the local voltage is too high, and the corona onset voltage is too high can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air purification, and particularly relates to a plasma generating device. BACKGROUND

[0002] Dielectric barrier discharge is a kind of non-equilibrium gas discharge under the barrier of insulating medium, which is widely used in low-temperature plasma generation, material processing and environmental protection and other fields. In the related art, the plasma generating device using the dielectric barrier discharge principle includes an inner electrode 1', an insulating layer 2' arranged around the outer side of the inner electrode 1', and an outer electrode 4' arranged outside the insulating layer 2', and 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, filamentary discharge is easily generated, and when the air gap 5' is too large, uneven distribution of electric field is easily caused, which leads to too high local electric field, and causes too high corona inception voltage. SUMMARY

[0004] Therefore, the present application provides a plasma generating device to solve the problems of difficult control of the size of the air gap, easy generation of filamentary discharge, or uneven distribution of electric field, which leads to too high local voltage and causes too high corona inception voltage in the related art.

[0005] The present application provides a plasma generating device, comprising:

[0006] an inner electrode;

[0007] an insulating layer arranged around the outer side of the inner electrode, and the outer periphery of the inner electrode is matched with the inner periphery of the insulating layer;

[0008] an outer electrode arranged outside the insulating layer, and the outer electrode is provided with a hollow region.

[0009] Beneficial effects: through such arrangement, the plasma generating device of the present application forms a structure of no gap or micro-gap between the inner electrode and the insulating layer.

[0010] In the discharge process, the hollow region on the outer electrode can replace the air gap between the inner electrode and the insulating layer to generate discharge, thereby avoiding the problems caused by the formation of the air gap between the inner electrode and the insulating layer, i.e. when the size of the air gap is too large, uneven distribution of electric field is easily caused, which leads to too high local electric field and causes too high corona inception voltage; when the air gap changes, it easily leads to unstable discharge, which causes problems such as affecting the reliability of long-term operation of the equipment.

[0011] On this basis, and because the plasma generating device of the embodiment of the present application cancels the air gap between the inner electrode and the insulating layer, oxidation, corrosion and even rust caused by the exposure of the inner electrode to the plasma environment are avoided, the corona inception voltage of the plasma generating device is increased due to rust, and the current stability of the plasma discharge device is improved, making the discharge more uniform, avoiding local overheating or sparking phenomenon, and being more suitable for long-term continuous use scenarios.

[0012] In addition, the plasma generating device of the embodiment of the present application can optimize the electric field distribution, control the discharge intensity, and reduce the local high temperature area, so that the ozone generation amount of the plasma generating device of the embodiment of the present application is significantly reduced under the same power, the safety and environmental protection of the equipment are improved, and the application scenarios sensitive to ozone such as air purification and medical disinfection are particularly suitable.

[0013] Therefore, the plasma generating device of the embodiment of the present application can overcome the problems of difficult control of the size of the air gap, easy generation of filamentary discharge, or uneven electric field distribution, which causes local voltage to be too high and the corona inception voltage to be too high.

[0014] In an alternative embodiment, the inner electrode is a conductive liquid or conductive glue filled in the insulating layer.

[0015] Beneficial effects: through such a setting, the conductive liquid or conductive glue can self-adaptively fill the grooves and holes on the inner wall of the insulating layer, so that the inner electrode is combined with the insulating layer as a whole to form a whole electrode structure, and the problems of difficult installation of the inner electrode into the insulating layer and even possible damage to the insulating layer during the installation process are avoided, and the operation is simple and convenient.

[0016] In an alternative embodiment, the inner electrode includes:

[0017] An electrode body;

[0018] A conductive layer arranged between the electrode body and the insulating layer and capable of filling the gap between the electrode body and the insulating layer.

[0019] Beneficial effects: through such a setting, the gap between the electrode body and the insulating layer is filled by the conductive layer, so that a gapless or micro-gap structure is formed between the inner electrode and the insulating layer, and the defects of difficult installation of the inner electrode into the insulating layer and even possible damage to the insulating layer during the installation process are avoided when the air gap is too small.

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

[0021] Beneficial effects: The conductive liquid has fluidity, can completely fill the gap between the electrode body and the insulating layer, avoid air gap caused by poor adhesion of the conductive layer to either the electrode body or the insulating layer, and can self-adaptively fill the grooves and holes on the surface of the electrode body or the insulating layer. The process is simple and the loss rate is low.

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

[0023] Beneficial effects: By coating process to form a conductive layer between the electrode body and the insulating layer, the thickness of the conductive layer can be accurately controlled, avoiding material waste and the risk of leakage and volatilization, and the conductive layer is not prone to frost heaving or shrinkage due to temperature changes, which helps to improve the stability of the operation of the plasma generating device.

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

[0025] Beneficial effects: When the conductive layer includes a conductive glue filled between the electrode body and the insulating layer, the conductive glue can be in a semi-liquid, gel-like or shapeable paste state, which can fill the small gap between the electrode body and the insulating layer.

[0026] After filling the conductive glue between the electrode body and the insulating layer, the conductive glue is cured by curing conditions suitable for the type of conductive glue, so that the conductive layer is tightly attached to the electrode body and the insulating layer.

[0027] When using conductive glue to form a conductive layer, the conductive glue can have fluidity in the initial state, can fully fill the small gap between the electrode body and the insulating layer, and can be tightly attached to the inner electrode and the insulating layer after curing, avoiding air gap caused by poor adhesion.

[0028] On this basis, the cured conductive glue also has a certain elasticity, which can absorb mechanical stress between the electrode body and the insulating layer when the plasma generating device is subjected to vibration, impact or temperature change by itself deformation, avoiding air gap between the electrode body and the insulating layer caused by rigid contact, thereby making the operation of the plasma generating device more stable, and helping to prolong the service life of the plasma generating device.

[0029] Again, the conductive glue can become solid after curing, without the risk of volatilization, leakage, etc., which can cause corrosion to the insulating layer or interfere with the discharge performance of the plasma generating device.

[0030] In an alternative embodiment, the outer electrode is a spiral electrode spirally wound outside the insulating layer, and the hollowed-out region is formed between two adjacent turns of the spiral electrode; or,

[0031] The outer electrode is a mesh electrode spirally wound outside the insulating layer, and the mesh holes of the mesh electrode are the hollowed-out regions; or,

[0032] The outer electrode comprises a plurality of conductive rings spirally wound outside the insulating layer, and the plurality of conductive rings are electrically connected in parallel.

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

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

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

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

[0037] In an alternative embodiment, the electrode comprises a conductive metal wire spirally wound outside the insulating layer, and the diameter of the conductive metal wire is r4, 0.03mm≤r4≤0.15mm; or,

[0038] The outer electrode comprises a plurality of conductive metal wires spirally wound outside the insulating layer, and the plurality of conductive metal wires are connected in parallel with each other, and the diameter of each conductive metal wire is r5, 0.03mm≤r5≤0.15mm; or,

[0039] The outer electrode is a carbon fiber bundle spirally wound outside the insulating layer.

[0040] Beneficial effects: when the outer electrode comprises a plurality of conductive metal wires spirally wound outside the insulating layer, the plurality of metal wires can form a more dense and uniform electric field distribution outside the insulating layer, avoid uneven discharge caused by local defects of a single metal wire, and avoid plasma generation device downtime caused by the breakage or failure of a certain metal wire, thereby making the operation of the plasma generation device more reliable.

[0041] In an alternative embodiment, the plasma generation device is an air purification device or a sterilization device. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the drawings needed to be used in the specific embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0043] Figure 1 A schematic view of a plasma generating device in the related art;

[0044] Figure 2 A sectional view of a plasma generating device in the related art at one angle;

[0045] Figure 3 A sectional view of a plasma generating device in the related art at another angle;

[0046] Figure 4 A sectional view of a plasma generating device in the related art at one angle;

[0047] Figure 5 A sectional view of a plasma generating device in the related art at another angle, in which conductive glue is filled between the inner electrode and the insulating layer;

[0048] Figure 6 A sectional view of a plasma generating device in the related art at another angle, in which conductive glue is filled between the inner electrode and the insulating layer; Figure 5

[0049] Figure 7 A sectional view of a plasma generating device in the related art at another angle, in which conductive glue is filled between the inner electrode and the insulating layer;

[0050] Figure 8 A discharge picture of a plasma generating device in the related art under the condition of a working frequency of 18.2 KHZ and a voltage of 3.8 KV;

[0051] Figure 9 A discharge picture of a plasma generating device in the related art under the condition of a working frequency of 18.2 KHZ and a voltage of 4.2 KV;

[0052] Figure 10 A discharge picture of a plasma generating device in the related art under the condition of a working frequency of 18.2 KHZ and a voltage of 3.2 KV;

[0053] Figure 11 A discharge picture of a plasma generating device in the related art under the condition of a working frequency of 18.2 KHZ and a voltage of 3.8 KV;

[0054] ​Figure 12 A discharge picture of the plasma generating device in the related art in a just running state;

[0055] Figure 13 A discharge picture of the plasma generating device in the related art after running for 100 hours;

[0056] Figure 14 A picture of an inner electrode of the plasma generating device in the related art after running for 100 hours;

[0057] Figure 15 A picture of an inner electrode of the plasma generating device in the related art after running for 800 hours;

[0058] Figure 16 A discharge picture of the plasma generating device in the related art after running for 800 hours;

[0059] Figure 17 A discharge picture of the plasma generating device in the related art under the condition of a working frequency of 12HZ and a voltage of 4.5KV;

[0060] Figure 18 A discharge picture of the plasma generating device in the related art under the condition of a working frequency of 12HZ and a voltage of 5KV;

[0061] Figure 19 A discharge picture of the plasma generating device in the related art under the condition of a working frequency of 12HZ and a voltage of 5.5KV;

[0062] Figure 20 A discharge picture of the plasma generating device in the related art under the condition of a working frequency of 12HZ and a voltage of 6KV;

[0063] Figure 21 A discharge picture of the plasma generating device in the related art under the condition of a working frequency of 12HZ and a voltage of 3KV;

[0064] Figure 22 A discharge picture of the plasma generating device in the related art under the condition of a working frequency of 12HZ and a voltage of 5KV;

[0065] Figure 23 A discharge picture of the plasma generating device in the related art under the condition of a working frequency of 12HZ and a voltage of 6KV;

[0066] Figure 24 A discharge picture of the plasma generating device in the related art under the condition of a working frequency of 12HZ and a voltage of 6.5KV.

[0067] BRIEF DESCRIPTION OF DRAWINGS

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

[0069] 2. Insulation layer;

[0070] 3. Conductive layer;

[0071] 4. External electrode; 401. Hollow area;

[0072] 1', inner electrode;

[0073] 2', insulation layer;

[0074] 4', external electrode;

[0075] 5', air gap. DETAILED DESCRIPTION

[0076] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0077] In the description of this application, it should be understood that the terms "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0078] like Figures 1 to 3 As shown, dielectric barrier discharge is a non-equilibrium gas discharge carried out under the barrier of an insulating medium. In related technologies, a plasma generating device that discharges based on the dielectric barrier discharge principle includes an inner electrode 1', an insulating layer 2' arranged around the outer surface of the inner electrode 1', and an outer electrode 4' arranged outside the insulating layer 2'. An air gap 5' is formed between the inner electrode 1' and the insulating layer 2'. During operation of the plasma generating device, discharge is formed in the air gap.

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

[0080] The corrosion of the electrode surface will change its conductivity, resulting in an increase in the local electric field strength, which will cause an increase in the corona inception voltage.

[0081] After the corona inception voltage is raised, the plasma generating device is difficult to maintain a stable discharge state, which seriously affects its purification function and service life.

[0082] In the related art, the corona inception voltage of the plasma generating device rises by more than 20% after 100 hours of operation, and the discharge performance significantly decreases.

[0083] On this basis, in the related art, during assembly, the inner electrode 1' usually needs to be inserted into the tubular insulating layer 2', but such an assembly method causes difficulty in controlling the size of the air gap 5'.

[0084] For example, when the size of the air gap 5' is too small, it is difficult to install the inner electrode 1' into the insulating layer 2', and even the insulating layer 2' can be damaged.

[0085] When the size of the air gap 5' is large, it is easy to cause uneven distribution of the electric field, causing the corona inception voltage to rise;

[0086] In addition, the change of the air gap 5' also causes unstable discharge, affecting the long-term operation reliability of the device.

[0087] For example, uneven air gap 5' causes electric field concentration, generates filamentary discharge, and increases ozone amount. Due to uneven air gap 5', the plug-in electrode is easy to form a local electric field concentration area, which is easy to cause filamentary discharge, not only reducing the discharge efficiency, but also causing impact and interference to the power supply system;

[0088] Filamentary discharge also causes local high temperature, further aggravating electrode corrosion and insulating layer 2' aging.

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

[0090] The embodiments of the present application will be described below in conjunction with Figures 4 to 24 .

[0091] According to the embodiments of the present application, in one aspect, 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 supply. The insulating layer 2 is arranged around the outer electrode 1, and the outer periphery of the inner electrode 1 is fitted with the inner periphery of the insulating layer 2. The outer electrode 4 is arranged outside the insulating layer 2, and the outer electrode 4 is provided with a hollow area 401.

[0093] By such an arrangement, the plasma generating device of the embodiments of the present application forms a gapless or micro-gap structure between the inner electrode 1 and the insulating layer 2.

[0094] During discharging, the hollowed-out area 401 on the outer electrode 4 can replace the air gap between the inner electrode 1 and the insulating layer 2 to cause discharging, thereby avoiding the problems caused by the air gap between the inner electrode 1 and the insulating layer 2, i.e., when the size of the air gap is too large, it is easy to cause uneven electric field distribution, trigger local electric field to be too high, and cause corona onset voltage to rise; when the air gap changes, it is easy to cause unstable discharging, and cause problems affecting the reliability of long-term operation of the equipment.

[0095] On this basis, and because the plasma generating device of the embodiment of the present application cancels the air gap between the inner electrode 1 and the insulating layer 2, it avoids the oxidation, corrosion, and even rust caused by the exposure of the inner electrode 1 to the plasma environment, can avoid the increase of the corona onset voltage of the plasma generating device due to rust, and improves the current stability of the plasma discharge device, makes the discharging more uniform, avoids local overheating or sparking phenomenon, and is more suitable for long-time continuous use scenarios.

[0096] In addition, because the plasma generating device of the embodiment of the present application can optimize the electric field distribution, control the discharging intensity, and reduce the local high-temperature area, under the same power, the ozone generation amount of the plasma generating device of the embodiment of the present application is significantly reduced, which can improve the safety and environmental protection of the equipment, and is particularly suitable for air purification, medical disinfection, and other ozone-sensitive application scenarios.

[0097] Therefore, the plasma generating device of the embodiment of the present application can overcome the problems in the related art that the size of the air gap is difficult to control, it is easy to cause damage to the insulating layer 2, generate filamentary discharge, or uneven electric field distribution, trigger local voltage to be too high, and cause the corona onset voltage to be too high.

[0098] The micro-gap structure refers to a micro gap between different objects or different parts of the same object, and the size of the micro gap is usually in the micron level or even nanometer level.

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

[0100] As a convertible embodiment, the inner electrode 1 is used for connecting ground, and the outer electrode 4 is used for connecting high voltage.

[0101] In one convertible embodiment, the power supply is an alternating current power supply, and the inner electrode 1 and the outer electrode 4 are respectively connected to one output end of the power supply.

[0102] In one embodiment, the inner electrode 1 is a conductive liquid or conductive glue filled in the insulating layer 2.

[0103] By so arranging, the conductive liquid or conductive glue can fill the grooves and holes on the inner periphery of the insulation layer 2 adaptively, so that the inner electrode 1 is combined with the insulation layer 2 as a whole to form a whole electrode structure, and the problems of installation difficulty and even possible damage to the insulation layer 2 in the process of installing the inner electrode 1 into the insulation layer 2 are avoided, and the operation is simple and convenient.

[0104] In one embodiment, the inner electrode 1 comprises an electrode body 101 and a conductive layer 3. The conductive layer 3 is arranged between the electrode body 101 and the insulation layer 2 and can fill the gap between the electrode body 101 and the insulation layer 2.

[0105] By so arranging, the gap between the electrode body 101 and the insulation layer 2 is filled by the conductive layer 3, so that a gapless or micro-gap structure is formed between the inner electrode 1 and the insulation layer 2, and the defects of installation difficulty and even possible damage to the insulation layer 2 in the process of installing the inner electrode 1 into the insulation layer 2 are avoided when the air gap is too small.

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

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

[0108] The conductive liquid has fluidity and can completely fill the gap between the electrode body 101 and the insulation layer 2, avoid air gap caused by poor adhesion of the conductive layer 3 to either the electrode body 101 or the insulation layer 2, and adaptively fill the grooves and holes on the surface of the electrode body 101 or the insulation layer 2. The process of filling the conductive liquid between the electrode body 101 and the insulation layer 2 is simple and has low loss rate.

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

[0110] In one embodiment, as shown in Figure 7 The conductive layer 3 comprises a conductive coating coated between the electrode body 101 and the insulation layer 2.

[0111] The conductive layer 3 is formed between the electrode body 101 and the insulation layer 2 by coating process, which can accurately control the thickness of the conductive layer 3, avoid material waste and leakage and volatilization risk, and is not prone to frost heaving or shrinkage of the conductive layer 3 due to temperature change, which helps to improve the stability of the operation of the plasma generating device.

[0112] The conductive coating is preferably but not limited to coated between the inner electrode 1 and the insulation layer 2 by brushing, spraying or dipping, etc.

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

[0114] When the conductive layer 3 comprises conductive glue filled between the electrode body 101 and the insulating layer 2, the conductive glue in the initial state can be semi-fluid, gel-like or malleable paste, which can fill the tiny gap between the electrode body 101 and the insulating layer 2.

[0115] After filling the conductive glue between the electrode body 101 and the insulating layer 2, the conductive glue is cured by curing conditions suitable for the type of conductive glue, so that the conductive layer 3 is tightly attached to the electrode body 101 and the insulating layer 2.

[0116] When using conductive glue to form the conductive layer 3, the conductive glue can have fluidity in the initial state, which can sufficiently fill the tiny gap between the electrode body 101 and the insulating layer 2, and can be tightly attached to the electrode body 101 and the insulating layer 2 after curing, avoiding air gap caused by poor adhesion.

[0117] On this basis, the cured conductive glue also has a certain elasticity, which can absorb the mechanical stress between the electrode body 101 and the insulating layer 2 by deforming itself when the plasma generating device is subjected to vibration, impact or temperature change, avoiding air gap between the electrode body 101 and the insulating layer 2 caused by rigid contact, thereby making the operation of the plasma generating device more stable, which helps to prolong the service life of the plasma generating device.

[0118] Again, the conductive glue can become solid after curing, without hidden dangers such as volatilization and leakage, which can cause corrosion to the insulating layer 2 or interfere with the discharge performance of the plasma generating device.

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

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

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

[0122] By such arrangement, in the discharge process of the plasma generating device, the discharge can be formed on the surface of the insulating layer 2 and located between the adjacent two turns of the spiral electrode.

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

[0124] By so arranging, in the process of discharging, the discharging can be formed on the surface of the insulating layer 2 and located in the mesh hole of the mesh electrode.

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

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

[0127] In one embodiment, the outer electrode 4 comprises a plurality of conductive rings surrounding the insulating layer 2, and the plurality of conductive rings are conductively connected.

[0128] By so arranging, in the process of discharging, the discharging can be formed on the surface of the insulating layer 2 and located between the adjacent two conductive rings.

[0129] In one embodiment, the conductive connection between the plurality of conductive rings is preferably but not limited to series connection or parallel connection.

[0130] In the description of the present application, the meaning of "plurality" is two or more, unless otherwise explicitly and specifically limited.

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

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

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

[0134] When the dielectric constant of the insulating layer 2 is in the above range, the risk of short circuit and electric leakage can be effectively prevented, and a stable electric field can be more easily formed at the working voltage of the electrode, taking into account 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 coating or electroplating.

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

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

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

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

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

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

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

[0143] In one embodiment, the outer electrode 4 comprises a spiral of conductive wire wound around the outside of the insulating layer 2, the diameter of the conductive wire being r4, 0.03 mm ≤ r4 ≤ 0.15 mm.

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

[0145] When the outer electrode 4 comprises a spiral of conductive wire wound around the outside of the insulating layer 2, the spiral of conductive wire can form a more dense and uniform electric field distribution outside the insulating layer 2, and can avoid uneven discharge caused by local defects of a single wire, and can avoid plasma device downtime caused by breakage or failure of a single wire, and can make the operation of the plasma generating device more reliable.

[0146] In one embodiment, the outer electrode 4 is a carbon fiber bundle wound in a spiral around the outside of the insulating layer 2.

[0147] In one embodiment, the carbon fiber bundle comprises 1000 carbon fibers, and the diameter of a single carbon fiber is 7 um.

[0148] Experiment 1:

[0149] The applicant recorded the discharge voltage and discharge phenomenon of the plasma generating device filled with conductive glue in the embodiments of the application, and compared it with the same type of product in the related art.

[0150] In the experiment, the inner electrode 1 was selected as a stainless steel wire with a diameter of 0.9 mm, the inner diameter of the insulating layer 2 was 1 mm, the thickness was 0.5 mm, and the outer electrode 4 was a carbon fiber bundle wound in a spiral around the outside of the insulating layer 2, the carbon fiber bundle was about 1000, and the diameter of a single carbon fiber was 7 um.

[0151] The applicant compared the discharge voltage and discharge brightness of the plasma generating device in the application and in the related art under the same conditions, and recorded the test results as follows:

[0152] Using a Su Man AC power supply, the discharge parameters were adjusted under the condition of a frequency of 18 KHZ. Through comparison, it can be seen that the single electrode is compared, such as Figure 10 andFigure 11 As shown in the condition that the conductive layer 3 is formed between the inner electrode 1 and the insulation layer 2, the striking voltage of the plasma generating device is 3.2KV;

[0153] As shown in the condition that the conductive layer 3 is formed between the inner electrode 1 and the insulation layer 2, the striking voltage of the plasma generating device is 3.2KV; Figure 8 And Figure 9 As shown in the condition that the conductive layer 3 is not formed, the striking voltage of the plasma generating device is 3.8KV, and the striking voltage difference is at least 600V;

[0154] Different materials and thicknesses of the insulation layer 2 have different effects on the striking voltage.

[0155] Experiment 2:

[0156] Figure 12 The discharge picture of the plasma generating device in the related art when it is just running under the condition of a voltage of 3.2KV, a working frequency of 10KHZ, a current of 170.5MA and a power of 31.2W.

[0157] Figure 13 The discharge picture of the plasma generating device in the related art after running for 100 hours, as shown in Figure 13 It can be seen that the single electrode of the plasma generating device in the related art is obviously weakened after running for 100 hours, and the voltage needs to be increased to 3.8KV, 10KHZ, and there are still some positions that do not discharge.

[0158] As shown in Figure 14 The surface of the inner electrode 1 of the plasma generating device in the related art appears obvious corrosion after running for 100 hours.

[0159] Figure 15 The inner electrode 1 picture of the plasma generating device in the embodiment of the application after running for 800 hours, it can be seen that the inner electrode 1 of the embodiment of the application has almost no corrosion.

[0160] Figure 16 The discharge picture of the plasma generating device in the embodiment of the application under the condition of a voltage of 3.2KV and a working frequency of 10KHZ, as shown in Figure 16 It can be seen that the discharge picture of the plasma generating device in the embodiment of the application has not changed basically, which shows that the conductive glue can effectively avoid the corrosion of the inner electrode 1.

[0161] Experiment 3:

[0162] The applicant records the discharge voltage and discharge phenomenon of the plasma generating device in the embodiment of the application whose inner electrode 1 is a conductive liquid, and compares it with the plasma generating device in the related art (the scheme of inserting the inner electrode 1 into the insulation layer 2).

[0163] After comparison, as shown inFigures 17 to 24 As shown, the striking voltage of the plasma generating device in the embodiment of the present application is much lower than that in the related art.

[0164] The striking voltage of the plasma generating device in the embodiment of the present application is 12 KHZ, 4.5 KV;

[0165] The striking voltage of the plasma generating device in the related art is 12 KHZ, 6.0 KV.

[0166] Through multiple experiments, it can be seen that the striking voltage of the electrode of the plasma generating device in the embodiment of the present application is greatly reduced, and the uniform stability of discharge is better.

[0167] Experiment 4:

[0168] The electrode structure with sealing conductive glue between the inner electrode 1 and the insulation layer 2 and the electrode structure without sealing conductive glue are respectively operated in a small cabin of 3 cubic meters for 2 hours, and the ozone concentration is compared.

[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 electrode structure without conductive glue is 48 PPB, which shows that filling the air gap with conductive glue can reduce the ozone concentration generated by discharge.

[0171] Through the test current pattern, it can also be seen that the current fluctuation of air gap discharge is larger, and the discharge is more unstable.

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

[0173] In summary, the plasma generating device in the embodiment of the present application can overcome the problems in the related art that the size of the air gap is difficult to control, the insulation layer 2 is easily damaged, filamentary discharge is generated, or the electric field distribution is uneven, which causes the local voltage to be too high, and the striking voltage to be too high.

[0174] Although the embodiments of the present application are described in conjunction with the drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope of the present application.

Claims

1. A plasma generating device, characterized in that: include: inner electrode (1); an insulating layer (2) arranged around the outer surface of the inner electrode (1), wherein 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 provided outside the insulating layer (2), and a hollow area (401) is provided on the external electrode (4).

2. The plasma generating device according to claim 1, characterized in that The inner electrode (1) is a conductive liquid or conductive glue poured into the insulating layer (2).

3. The plasma generating device according to claim 1, wherein The inner electrode (1) comprises: an electrode body (101); The conductive layer (3) is provided 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 according to claim 3, characterized in that The conductive layer (3) includes a conductive liquid injected between the electrode body (101) and the insulating layer (2).

5. The plasma generating device according to claim 3, characterized in that The conductive layer (3) includes a conductive coating layer coated between the electrode body (101) and the insulating layer (2).

6. The plasma generating device according to claim 3, characterized in that The conductive layer (3) includes conductive glue 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 outside of the insulating layer (2), and the hollow area (401) is formed between two adjacent turns of the spiral electrode; or, The outer electrode (4) is a mesh electrode arranged around the outside of the insulating layer (2), and the mesh holes of the mesh electrode are the hollow areas (401); or, The outer electrode (4) comprises a plurality of conductive rings surrounding the outside of the insulating layer (2), and the plurality of conductive rings are conductively connected.

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

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

12. The plasma generating device according to any one of claims 1 to 6, characterized in that: The plasma generating device is an air purification device or a disinfection device.

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