Active gas injection device

Abstract

The present disclosure provides an active gas injection device having sufficient cell activation ability, disinfection and sterilization effects, and high healing efficiency. The active gas injection device includes a lance and a supply unit including a power source. The torch includes a plasma generating portion, a housing covering the plasma generating portion, and an injection pipe. The plasma generation unit is provided with: a tubular dielectric that has a part of a first gas flow path therein and into which a working gas is introduced; an internal electrode that is provided inside the tubular dielectric, extends in the tube axis direction of the tubular dielectric, and is separated from the tubular dielectric; and an external electrode provided on the outside of the tubular dielectric and facing the internal electrode across the tubular dielectric. The power supply generates plasma by applying a voltage to the plasma generation unit, the ejection tube has an ejection port for ejecting the active gas at the tip thereof, and the temperature of the active gas at a surface to be ejected, which is 1-10 mm away from the ejection port, exceeds 40 DEG C.

Description

Technical Field

[0001] This disclosure relates to an active gas injection device. Background Technology

[0002] Currently, in medical applications such as dental treatment, devices capable of generating low-temperature plasma are used for anti-inflammatory and therapeutic purposes. For example, Patent Document 1 discloses a plasma therapy device having a flexible tube for air circulation and wire passage, and a handheld part connected to the flexible tube. Low-temperature plasma with a lower temperature is ejected from the front end of the handheld part for dental treatment.

[0003] However, while low-temperature plasma can rapidly kill various bacteria, viruses, and cancer cells, it suffers from insufficient activity, inadequate disinfection and sterilization effects, and room for improvement in treatment efficiency. Therefore, there is room for further improvement in existing plasma therapy devices.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: JP2013-128681A Utility Model Content

[0007] This disclosure was made in consideration of the above circumstances, and its purpose is to provide an active gas injection device with sufficient cell activation capacity, disinfection and sterilization effect and high cure efficiency.

[0008] The disclosed active gas injection device includes a spray gun and a power supply unit connected to the spray gun. The spray gun has a plasma generating section, a housing covering the plasma generating section, and an injection tube disposed at the front end of the housing. The plasma generating section includes: a tubular dielectric having a portion of a first gas flow path inside, through which a working gas is introduced; an internal electrode disposed inside the tubular dielectric, extending along the tube axis of the tubular dielectric and separated from the tubular dielectric; and an external electrode disposed outside the tubular dielectric, facing the internal electrode across the tubular dielectric. The power supply generates plasma by applying a voltage to the plasma generating section. The injection tube has an injection port at its front end from which an active gas activated by the plasma is ejected. The temperature of the active gas at the sprayed surface at a distance of 1 mm to 10 mm from the injection port exceeds 40°C.

[0009] According to the reactive gas injection device of this disclosure, the power supply includes an adjustment unit for adjusting the voltage applied to the plasma generating unit.

[0010] According to the active gas injection device disclosed herein, the adjustment unit adjusts the voltage applied to the plasma generating unit to 13kV or higher.

[0011] According to the active gas injection device disclosed herein, the adjustment unit adjusts the frequency of the voltage applied to the plasma generating unit to 7 kHz or higher.

[0012] According to the active gas injection device disclosed herein, the housing is formed in a tubular shape, the housing comprising: a main body portion which, together with the tubular dielectric, forms a first gas flow path; and a connecting portion disposed at the front end of the main body portion and having a second gas flow path inside, wherein the distance between the end of the external electrode near the injection port and the rear end of the connecting portion is 10-25 mm.

[0013] According to the active gas injection device disclosed herein, the injection tube has a third gas flow path inside and is detachably mounted to the front end of the connector.

[0014] According to the active gas injection device disclosed herein, the inner diameter of the second gas flow path is the same as that of the third gas flow path, and is 1 / 4 to 1 / 12 of the inner diameter of the first gas flow path.

[0015] According to the active gas injection device of this disclosure, the first gas flow path, the second gas flow path, and the third gas flow path are arranged on the same axis along the tube axis direction.

[0016] According to the active gas injection device disclosed herein, the main body includes an outer skin member and an insulating member disposed close to the inner side of the outer skin member, a portion of the insulating member covering the tubular dielectric and the external electrode in a close-fitting manner.

[0017] According to the active gas injection device disclosed herein, an active gas injection device with sufficient cell activation capacity, disinfection and sterilization effect and high cure efficiency can be provided. Attached Figure Description

[0018] The objects, features, and advantages of this disclosure will become clearer from the following description of embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0019] Figure 1 This is a schematic diagram showing the active gas injection device of this disclosure in use;

[0020] Figure 2 This is a block diagram showing the general structure of the active gas injection device of this disclosure;

[0021] Figure 3 This is a block diagram showing the general structure of the active gas injection device of this disclosure;

[0022] Figure 4 This is a schematic diagram illustrating an example of the active gas injection device of this disclosure;

[0023] Figure 5 This is a partial cross-sectional view of a spray gun illustrating one embodiment of the present disclosure;

[0024] Figure 6 Indicates along Figure 5 A cross-sectional view along line AA;

[0025] Figure 7 The inner diameter relationship of the first to third gas flow paths is schematically shown.

[0026] Explanation of reference numerals in the attached figures

[0027] 1. Active gas injection device;

[0028] 10 spray guns;

[0029] 10A Plasma Generation Unit;

[0030] 11. Tubular dielectric;

[0031] 11X Tube axis direction;

[0032] 12 Internal electrodes;

[0033] 13. External electrodes;

[0034] 10B Housing;

[0035] 14. Main body section;

[0036] 14O outer skin components;

[0037] 14I Insulating components;

[0038] 14F First gas flow path;

[0039] 15. Connecting parts;

[0040] 15F Second Gas Flow Path;

[0041] 10C injection nozzle;

[0042] 16F Third Gas Flow Path;

[0043] 17. Injection nozzle;

[0044] S is the surface being sprayed. Detailed Implementation

[0045] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0046] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “having”, “comprising”, etc., as used herein indicate the presence of the said features, operations, and / or components, but do not exclude the presence or addition of one or more other features, operations, or components.

[0047] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0048] When using expressions such as "at least one of A, B, and C," they should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "an apparatus having at least one of A, B, and C" should include, but is not limited to, having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). A person skilled in the art should also understand that any conjunction and / or phrase that substantially arbitrarily represents two or more alternative items, whether in the specification, claims, or drawings, should be understood to give the possibility of including one of these items, either of these items, or both items. For example, the phrase "A or B" should be understood to include the possibility of "A" or "B," or "A and B."

[0049] In addition, for ease of understanding, the scale and aspect ratio of the actual objects in the attached drawings have been appropriately altered or exaggerated.

[0050] This disclosure provides an active gas injection device. The active gas injection device includes a spray gun and a power supply unit connected to the spray gun. The spray gun has a plasma generating section, a housing covering the plasma generating section, and an injection tube disposed at the front end of the housing. The plasma generating section includes a tubular dielectric, an internal electrode, and an external electrode. The tubular dielectric has a portion of a first gas flow path inside, through which a working gas is introduced. The internal electrode is disposed inside the tubular dielectric, extends along the axis of the tubular dielectric, and is separate from the tubular dielectric. The external electrode is disposed outside the tubular dielectric, facing the internal electrode across the tubular dielectric. The power supply generates plasma by applying a voltage to the plasma generating section. The injection tube has an injection port at its front end from which the active gas activated by the plasma is ejected. The temperature of the active gas at the sprayed surface at a distance of 1 mm to 10 mm from the injection port exceeds 40°C.

[0051] The following is for reference Figures 1 to 7 The active gas injection device disclosed herein will be described.

[0052] The active gas injection device 1 disclosed herein is mainly used for sterilization, disinfection, and healing of wound surfaces and other surfaces to be sprayed. Figure 1 This is a schematic diagram illustrating the operational state of the active gas injection device 1 of this disclosure. The spray gun 10 of the active gas injection device 1, for example, is operated by a doctor or other operator, and has a shape, size, and weight suitable for easy hand-held operation. Figure 1 As shown, the operator holds a spray gun and sprays an active gas from the nozzle onto the surface S being sprayed. This active gas contains active species generated through plasma activation, which has the effect of promoting the healing of external injuries and abnormalities. By irradiating cells, living tissues, or biological individuals with active gas containing active species, it is possible to produce effects such as promoting the cleansing, activation, and healing of the irradiated part. Examples of active species include: hydroxyl radicals, singlet oxygen, ozone, hydrogen peroxide, superoxide anion radicals, and other reactive oxygen species; and nitric oxide, nitrogen dioxide, peroxynitrite, peroxynitrite, and dinitrogen trioxide, and other reactive nitrogen species.

[0053] Figure 2 This is a block diagram showing the general structure of the active gas injection device 1 of this disclosure. Figure 2As shown, the active gas injection device 1 may include a spray gun 10 and a supply unit 50 connected to the spray gun 10. The supply unit 50 includes a power supply 20 that supplies power to the spray gun 10. The active gas injection device 1 may also include a gas supply section 30 that supplies working gas to the spray gun 10. The active gas injection device 1 may also include a control unit 40, which can control the spray gun 10, the supply unit 50, and the gas supply section 30 respectively. The control unit 40 may also be connected to an input section, a display section (not shown), via wired or wireless means.

[0054] In another scheme, such as Figure 3 As shown, the gas supply unit 30 may also be included in the supply unit 50.

[0055] Figure 4 This is a schematic diagram illustrating an example of the active gas injection device 1 of this disclosure, visually demonstrating... Figure 3 The connection method between the spray gun 10 and the power supply 20, air supply unit 30, etc. in the supply unit 50 is shown.

[0056] like Figure 4 As shown, the power supply line 210 connecting the power source 20 to the spray gun 10 and the air supply pipe 310 connecting the air supply unit 30 to the spray gun 10 are, for example, housed within a single pipe 32. Similarly, the grounding wire of the spray gun 10 can also be housed within this pipe 32. In other words, the end of the spray gun 10 is connected to the supply unit 50 via only one pipe 32. Therefore, the active gas injection device 1 of this disclosure has a simple structure and is easy to move and use.

[0057] Figure 5 yes Figure 4 A partial cross-sectional view of the spray gun 10 shown.

[0058] like Figure 5 As shown, the spray gun 10 has a plasma generating section 10A, a housing 10B covering the plasma generating section 10A, and a spray pipe 10C disposed at the front end of the housing 10B.

[0059] The plasma generating unit 10A includes a tubular dielectric 11, an internal electrode 12, and an external electrode 13. The tubular dielectric 11 is a cylindrical component extending in the axial direction 11X, and has a portion of a first gas flow path 14F inside, through which a working gas is introduced. The internal electrode 12 is disposed inside the tubular dielectric 11, extends along the axial direction 11X of the tubular dielectric 11, and is separate from the tubular dielectric 11. The external electrode 13 is disposed outside the tubular dielectric 11, and is positioned opposite the internal electrode 12 across the tubular dielectric 11.

[0060] When the active gas injection device 1 is in operation, power is supplied to the plasma generation unit 10A by the power source 20, thereby applying a voltage between the internal electrode 12 and the external electrode 13 of the plasma generation unit 10A. At the same time, the working gas is introduced into a part of the first gas flow path 14F of the tubular dielectric 11. The type of working gas is not particularly limited, and gases such as oxygen, helium, argon, nitrogen, carbon dioxide, and air can be used.

[0061] In this disclosure, the internal electrode 12 and the external electrode 13 are positioned opposite each other in a direction perpendicular to the flow direction of the working gas. When a voltage is applied between the internal electrode 12 and the external electrode 13, the working gas is ionized at the position where the outer peripheral surface of the internal electrode 12 faces the inner peripheral surface of the external electrode 13, becoming plasma. This plasma is then guided sequentially along the first gas flow path 14F, the second gas flow path 15F, and the third gas flow path 16F to the nozzle 17. At the plasma generation section 10A, the plasma generated based on the working gas is an active gas containing ions, electrons, excited molecules and atoms, and a small amount of active species. As the plasma moves away from the plasma generation section 10A, the ionized ions and electrons in the active gas recombine, causing a change in the active components. At the point of being guided to the nozzle 17, the active species become the main active components in the gas. As a result, the active gas activated by the plasma is ejected from the nozzle 17 at the front end of the ejector tube 10C. As mentioned earlier, depending on the type of working gas, reactive gases can include, for example, the following reactive oxygen species: hydroxyl radicals, singlet oxygen, ozone, hydrogen peroxide, superoxide anion radicals, etc.; and reactive nitrogen species: nitric oxide, nitrogen dioxide, peroxynitrite, peroxynitrite, and dinitrogen trioxide, etc. These reactive species exhibit significant activity in the sterilization of sprayed surfaces such as skin, and in the healing of wounds.

[0062] In this disclosure, the temperature of the active gas at the sprayed surface S, which is 1 mm or more but less than 10 mm away from the injection port 17, exceeds 40°C.

[0063] The inventors of this disclosure have discovered that if the temperature of the sprayed gas is too low, the concentration of active species in the active gas is insufficient, which cannot provide sufficient cell activation capacity and disinfection and sterilization effect, thus affecting the cure efficiency.

[0064] Simultaneously, appropriately heating the skin and other surfaces being sprayed can dilate local blood vessels, increasing blood flow and relieving muscle tension while improving tissue suppleness. Furthermore, the increased blood flow delivers more oxygen, nutrients, and antioxidants, thereby accelerating cell metabolism and enhancing the body's self-healing abilities.

[0065] Therefore, by setting the temperature of the active gas at the sprayed surface S to over 40°C, a synergistic effect can be achieved by the active species outside the body and the vasodilation inside the body, resulting in a high cure rate.

[0066] In particular, the improvement in healing efficiency is more pronounced when the sprayed surface does not show signs of bleeding or inflammation.

[0067] As a preferred embodiment, the temperature of the active gas at the sprayed surface S, which is at a distance of more than 1 mm and less than 10 mm from the injection port 17, exceeds 50°C.

[0068] In this disclosure, because the concentration of active species in the active gas ejected from the active gas ejection device is relatively high, disinfection and sterilization of the sprayed surface such as skin, wound healing, etc., usually only require a few tens of seconds or even a few seconds of spraying, which can speed up the operation. Furthermore, because the spraying time is short, even if the temperature of the active gas is high during spraying, burns will not occur immediately.

[0069] The temperature at which the sprayed surface will not be burned is related to the spraying time. Basically, the shorter the spraying time, the less likely the sprayed surface will be burned. From the point of view of preventing burns, the temperature of the active gas at the sprayed surface S, which is 1 mm or more but less than 10 mm away from the spray nozzle 17, is preferably less than 70°C, more preferably less than 65°C, and even more preferably less than 60°C.

[0070] In order to control the temperature of the reactive gas at the injection surface S within the aforementioned range, in one embodiment, the power supply 20 includes an adjustment unit that adjusts the voltage applied to the plasma generation unit 10A. This adjustment unit can adjust the magnitude and frequency of the voltage applied by the power supply 20 to the plasma generation unit 10A. Therefore, the temperature of the reactive gas can be accurately controlled to the target value.

[0071] In one embodiment, the adjustment unit adjusts the voltage applied by the power supply 20 to the plasma generation unit 10A to 13kV or higher.

[0072] In another embodiment, the adjustment unit adjusts the frequency of the voltage applied by the power supply 20 to the plasma generation unit 10A to 7 kHz or higher.

[0073] This enables the achievement of high plasma generation efficiency, which helps ensure that the temperature of the active gas at the sprayed surface S, which is more than 1 mm but less than 10 mm away from the nozzle 17, exceeds 40°C.

[0074] In this disclosure, the internal electrode 12 is formed in a generally cylindrical or rod-shaped manner, and may have various shapes of protrusions, holes, etc., on the electrode surface opposite the external electrode 13. The cross-sectional shape of the internal electrode 12 perpendicular to the tube axis direction 11X is not particularly limited, and can be, for example, circular, elliptical, quadrilateral, hexagonal, etc. The material of the internal electrode 12 is not particularly limited as long as it is a conductive material; metals used in electrodes of known plasma generating devices can be used. Examples of materials for the internal electrode 12 include stainless steel, copper, tungsten, and carbon.

[0075] In this disclosure, the shape of the external electrode 13 is not particularly limited as long as it can be oriented to face the internal electrode 12 along the tubular dielectric 11. Examples of suitable shapes include cylindrical, rod-shaped, and plate-shaped electrodes. Preferably, the external electrode 13 is cylindrical, allowing it to fit snugly against the outer peripheral surface of the tubular dielectric 11. By making the external electrode 13 cylindrical, the inner peripheral surface of the external electrode 13 can be reliably aligned with the outer peripheral surface of the internal electrode 12, improving plasma generation efficiency. The material of the external electrode 13 is not particularly limited as long as it is a conductive material; metals used in electrodes of known plasma generation devices can be used. Examples of suitable materials for the external electrode 13 include stainless steel, copper, tungsten, and carbon.

[0076] In one embodiment of this disclosure, the entire surface of the external electrode 13 is opposed to the internal electrode 12 in the tube axis direction 11X, thereby maximizing the area of ​​the opposing region between the external electrode 13 and the internal electrode 12, and further improving the plasma generation efficiency which is positively correlated with this area.

[0077] The cross-sectional shape of the tubular dielectric 11 disclosed herein, perpendicular to the tube axis direction 11X, is not particularly limited. For example, it can be circular, elliptical, quadrilateral, hexagonal, or similar shapes, corresponding to the aforementioned internal electrode 12. However, the tubular dielectric 11 is preferably cylindrical or similar shapes that allow it to fit tightly against the inner circumferential surface of the external electrode 13. The material of the tubular dielectric 11 is not particularly limited, and dielectric materials used in known plasma generating devices can be used. Examples of materials for the tubular dielectric 11 include glass, ceramics, and synthetic resins.

[0078] In this disclosure, considering the plasma generation efficiency and the temperature of the ejected active gas, the tubular dielectric 11 is preferably characterized by a high relative permittivity and a thin thickness.

[0079] like Figure 6 As shown in the cross-sectional view, preferably, the cylindrical housing body 14, the cylindrical external electrode 13, the cylindrical tubular dielectric 11, and the cylindrical internal electrode 12 are arranged in concentric circles from the outside towards the center.

[0080] In one embodiment of this disclosure, the housing 10B is formed in a tubular shape. The housing 10B includes a main body portion 14 and a connecting portion 15 disposed at the front end of the main body portion 14. The main body portion 14 of the housing 10B and the tubular dielectric 11 of the plasma generating portion 10A together form a first gas flow path 14F, the connecting portion 15 of the housing 10B has a second gas flow path 15F inside, and the injection pipe 10C has a third gas flow path 16F inside.

[0081] The main body 14 in the housing 10B can be made of an insulating material. However, the main body 14 can also be made of a non-insulating material such as metal. In this case, the main body 14 includes a metal outer skin member 14O and an insulating member 14I disposed close to the inside of the outer skin member. The insulating member 14I is used to separate the metal external electrode 13 disposed inside the housing 10B from the metal outer skin member 14O of the housing 10B. Furthermore, a portion of the insulating member 14I covers the tubular dielectric 11 and the external electrode 13 in a close-fitting manner.

[0082] In the spray gun 10 of the active gas injection device 1, the distance L between the end of the external electrode 13 near the injection port 17 and the rear end of the connecting part 15 is 10-25 mm.

[0083] In this disclosure, the diameter of the first gas flow path 14F is larger than the diameters of the second gas flow path 15F and the third gas flow path 16F. Therefore, by setting the distance L between the end of the external electrode 13 near the injection port 17 and the rear end of the connecting portion 15 to 10-25 mm, the plasma generated at the plasma generation unit 10A can first pass through the larger diameter first gas flow path 14F, thereby ensuring space for efficient conversion of plasma into reactive gas and improving plasma conversion efficiency.

[0084] Furthermore, the connecting portion 15 in the housing 10B can also be made of insulating or non-insulating material. When the connecting portion 15 is made of a non-insulating material such as metal, by setting the aforementioned distance L to 10-25 mm, it is also possible to prevent the connecting portion 15 from affecting the plasma generation effect at the plasma generation unit 10A.

[0085] In this disclosure, the injection pipe 10C is detachably mounted to the front end of the connector 15.

[0086] For example, the spray nozzle 10C can be installed in a detachable manner at the front end of the connector 15 by plugging or threading. This facilitates the installation and removal of the spray nozzle 10C, allowing for timely replacement and cleaning of the spray nozzle 10C after each use of the spray gun 10.

[0087] The material of the spray nozzle 10C is not particularly limited; it may or may not be insulating. In cases of repeated use, the material of the spray nozzle 10C is preferably a material with excellent wear resistance and corrosion resistance. Examples of materials with excellent wear resistance and corrosion resistance include metals such as stainless steel.

[0088] In one embodiment of this disclosure, such as Figure 7 As shown, the inner diameters of the second gas flow path 15F and the third gas flow path 16F are the same, and are 1 / 4 to 1 / 12 of the inner diameter of the first gas flow path 14F. Therefore, the gas that achieves efficient conversion of active species in the first gas flow path 14F is compressed during its passage through the second gas flow path 15F and the third gas flow path 16F, resulting in an increase in the content and concentration of active species. Furthermore, the velocity of the active gas as it is ejected from the nozzle 17 to the surface S increases, thus better enabling it to perform its functions of cleaning, activation, and healing.

[0089] Additionally, in one of the solutions disclosed herein, such as Figure 7 As shown, the first gas flow path 14F, the second gas flow path 15F, and the third gas flow path 16F are arranged on the same axis along the tube axis direction 11X.

[0090] In this way, the centers of each gas flow path are aligned on the same straight line, resulting in minimal energy loss during the process of the working gas transforming into plasma and then into active gas.

[0091] In summary, the active gas injection device disclosed herein can provide an active gas injection device with sufficient cell activation capacity, disinfection and sterilization effect, and high cure efficiency.

[0092] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0093] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. An active gas injection device comprising a spray gun and a power supply unit connected to the spray gun, characterized in that, The spray gun has a plasma generating section, a housing covering the plasma generating section, and a spray pipe disposed at the front end of the housing. The plasma generating unit includes: A tubular dielectric having a portion of a first gas flow path inside, through which a working gas is introduced; An internal electrode is disposed inside the tubular dielectric, extends along the tube axis of the tubular dielectric, and is separate from the tubular dielectric. as well as An external electrode is disposed on the outside of the tubular dielectric, facing the internal electrode across the tubular dielectric. The power source generates plasma by applying voltage to the plasma generating unit. The injection pipe has an injection port at its front end for ejecting the active gas obtained by the activation of the plasma. The temperature of the active gas at the sprayed surface, which is more than 1 mm but less than 10 mm away from the injection port, exceeds 40°C.

2. The active gas injection device according to claim 1, characterized in that, The power supply includes an adjustment unit that adjusts the voltage applied to the plasma generating unit.

3. The active gas injection device according to claim 2, characterized in that, The adjustment unit adjusts the voltage applied to the plasma generating unit to 13kV or higher.

4. The active gas injection device according to claim 2, characterized in that, The adjustment unit adjusts the frequency of the voltage applied to the plasma generating unit to 7 kHz or higher.

5. The active gas injection device according to any one of claims 1 to 4, characterized in that, The shell is formed in a tubular shape. The housing includes: a main body portion that, together with the tubular dielectric, forms the first gas flow path; and a connecting portion disposed at the front end of the main body portion and having a second gas flow path internally. The distance between the end of the external electrode near the nozzle and the rear end of the connector is 10-25 mm.

6. The active gas injection device according to claim 5, characterized in that, The injection pipe has a third gas flow path inside and is installed at the front end of the connector in a detachable manner.

7. The active gas injection device according to claim 6, characterized in that, The second gas flow path has the same inner diameter as the third gas flow path, and is 1 / 4 to 1 / 12 of the inner diameter of the first gas flow path.

8. The active gas injection device according to claim 6, characterized in that, The first gas flow path, the second gas flow path, and the third gas flow path are arranged on the same axis along the tube axis direction.

9. The active gas injection device according to claim 5, characterized in that, The main body includes an outer skin component and an insulating component disposed close to the inner side of the outer skin component. A portion of the insulating member covers the tubular dielectric and the external electrode in a close-fitting manner.

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