WO2007105330A1

WO2007105330A1 - Glow plasma generator and method for generating glow plasma

Info

Publication number: WO2007105330A1
Application number: PCT/JP2006/317652
Authority: WO
Inventors: Katsuhisa Kitano; Hironori Aoki; Satoshi Hamaguchi
Original assignee: Juridical Foundation Osaka Industrial Promotion Organization; Osaka University
Priority date: 2006-03-06
Filing date: 2006-09-06
Publication date: 2007-09-20
Also published as: JP4590528B2; JPWO2007105330A1

Abstract

There is provided a glow plasma generator capable of constantly generating glow plasma in a vapor phase contacting with a liquid phase under a condition where a liquid (100) and an ambient gas (101) are mixed with each other. The glow plasma generator (1) comprises a storage (10), which is composed of a dielectric material and capable of internally storing the liquid (100) and the ambient gas (101), gas atmosphere creation apparatuses (4, 6) for having the inside of the storage in a state where the ambient gas is present; a rod-shaped internal electrode (11) provided inside the storage (10); a board-like external electrode (12) provided on the outer peripheral wall (14) of the storage (10) and disposed such that the distance from the internal electrode (11) disposed so as to sandwich the storage (10) varies locally; and a voltage application device (3) for applying a high frequency voltage between the internal and external electrodes and inducing a dielectric barrier discharge between the internal and external electrodes.

Description

Specification

Glow plasma generator and glow plasma generation method

Technical field

TECHNICAL FIELD [0001] The present invention relates to a glow plasma generating apparatus and a glow plasma generating method that are suitably used for plasma polymerization, sterilization, water purification, and the like. More specifically, the present invention relates to a liquid surface or a liquid in a liquid. TECHNICAL FIELD The present invention relates to an apparatus for generating a plasma and a method for generating a glow plasma.

Conventionally, it has been possible to generate plasma in water mainly using high-voltage pulse discharge. For example, JP-T-2005-529455, JP-A-2004-268003, JP-A-2005-21869, etc. disclose an apparatus for generating plasma in a liquid. For example, the device described in JP-T-2005-529455 is a device that inserts a pair of metal electrodes into an electrically conductive liquid and generates plasma in the bubble region using the gas generated by electrolysis as an atmospheric gas. It is. In other words, an electrically conductive aqueous solution is electrolyzed using a high-voltage DC power source to generate hydrogen and oxygen bubbles on the electrode surface. Since bubbles have a higher resistance than aqueous solutions, a high voltage is divided into the bubbles so that discharge occurs in the bubble region.

Disclosure of the invention

Problems to be solved by the invention

[0003] However, in the device that is described in JP-T-2005-529455, it is necessary to generate plasma in the gas bubble region generated by electrolysis, so it is not possible to target any liquid! /, There is a problem!

[0004] In addition, by generating plasma in the gas phase in contact with the liquid phase, new developments in plasma chemistry, bioscience, and the like can be expected. For this purpose, it is preferable to use a low temperature non-equilibrium glow discharge in order to bring the plasma into liquid contact for a long time. However, the above-mentioned devices are mainly streamer discharges and arc discharges in which they are grown, and the plasma parameters produced by these discharges. The data was inherently difficult to control. In addition, since it generates locally high temperature and high density, its application range was limited to sterilization.

[0005] On the other hand, in order to generate a glow plasma in a state where water is mixed with atmospheric gas, it is generally preferable to lower the atmospheric pressure in the container. However, if the atmospheric pressure in the container is lowered, the liquid in the container will boil and the liquid level will be disturbed, and the liquid will come into contact with the electrode and the secondary electron supply from the electrode will be obstructed. There is a possibility that a new problem will occur. In addition, there is a problem that impurities are mixed into the atmospheric gas when liquid vapor is mixed into the atmospheric gas. Therefore, atmospheric pressure plasma, which discharges at a pressure higher than the vapor pressure so that water does not boil, is also being considered.

[0006] In a state where water and atmospheric gas coexist, conditions such as internal atmospheric pressure change every moment due to water evaporation. Therefore, it is difficult to set conditions for generating plasma, and it is extremely difficult to constantly generate glow plasma at atmospheric pressure.

[0007] Therefore, the technical problem to be solved by the present invention is to solve the above-mentioned problems by making globular plasma steady in a gas phase in contact with the liquid phase in a state where the liquid and the atmospheric gas are mixed. It is an object of the present invention to provide a glow plasma generating apparatus and a globe plasma generating method that can be generated in an automatic manner.

Means for solving the problem

In order to solve the above technical problem, the present invention provides a glow plasma generating apparatus having the following configuration.

[0009] According to a first aspect of the present invention, there is provided a glow plasma generator comprising a storage unit configured to store an atmospheric gas, a first electrode, and a second electrode,

At least a part of the storage part is a dielectric part made of a dielectric,

Between the first electrode and the second electrode, at least a part of the atmospheric gas and the dielectric part of the reservoir are interposed,

There is provided a glow plasma generating apparatus in which a distance between the first electrode side and the second electrode side of the at least part of the atmospheric gas is partially different.

[0010] According to the second aspect of the present invention, the dielectric part of the storage part has a first part and a second part. And

The first electrode is provided so as to cover at least a part of the first portion of the storage portion,

The second electrode is provided so as to cover at least a part of the second portion of the storage portion,

Between the first electrode and the second electrode, the at least part of the atmospheric gas, the first part of the storage part and the second part are interposed,

A glow plasma generator according to a first aspect is provided, wherein the distance between the first portion of the reservoir and the second portion of the reservoir is partially different.

[0011] According to the third aspect of the present invention, the first electrode is provided so as to cover the dielectric portion of the storage portion,

Between the first electrode and the second electrode, the at least part of the atmospheric gas and the dielectric portion of the storage portion are interposed,

A glow plasma generator according to a first aspect is provided in which a distance between the dielectric portion of the reservoir and the second electrode side is partially different.

[0012] According to a fourth aspect of the present invention, the storage section has a partition wall that defines an interior for storing the atmospheric gas and an exterior that does not store the atmospheric gas.

The first electrode is provided on the outer side of the partition wall of the storage part, and the second electrode is provided on the inner side of the partition wall of the storage part. A plasma generator is provided.

[0013] According to a fifth aspect of the present invention, there is provided the glow plasma generating apparatus according to the fourth aspect, wherein the second electrode is provided at a position eccentric from the inner center of the reservoir. .

[0014] According to a sixth aspect of the present invention, there is provided the glove plasma generating device according to the fourth aspect, wherein the second electrode is spiral.

[0015] According to a seventh aspect of the present invention, there is provided the glow plasma generating apparatus according to the fourth aspect, wherein the second electrode comes into contact with an inner side surface of the partition wall of the storage section.

[0016] According to the eighth aspect of the present invention, the distance between the first electrode side and the second electrode side is different in part so as to be distributed discretely. No glow plasma Provide raw equipment.

[0017] According to the ninth aspect of the present invention, the storage section is configured to store a liquid.

The fourth aspect of the present invention provides a glow plasma generator.

[0018] According to a tenth aspect of the present invention, there is provided a method of generating glow plasma by a glow plasma generator,

The glow plasma generator comprises:

A storage portion configured to store an atmospheric gas, a first electrode, and a second electrode, wherein at least a part of the storage portion is a dielectric portion formed of a dielectric;

The distance between the first electrode side and the second electrode side of the at least part of the atmospheric gas is partially different,

The glow plasma generation method includes:

Including a discharge generating step of generating a discharge between the first electrode side and the second electrode side by applying a voltage between the first electrode and the second electrode. A plasma generation method is provided.

[0019] In the configuration described above, in the process of generating the discharge, it is preferable to reduce the pressure in the storage unit while increasing the pressure in the storage unit after the discharge has occurred.

The invention's effect

[0020] According to the glow plasma generator of the present invention, at least a part of the atmospheric gas and the at least a part of the storage part are interposed between the first electrode and the second electrode. The distance between the first electrode side and the second electrode side in the region where at least a part of the atmospheric gas intervenes is partially different.

[0021] Accordingly, among the partially different intervals, an appropriate interval that can maintain the glow plasma in accordance with various conditions (such as pressure) in the reservoir is automatically selected, and the first electrode side and the second electrode are selected. Dielectric barrier discharge occurs between the two sides. As a result, it is possible to set the conditions in the storage section within a wide range. [0022] Further, the first part and the second part of the storage part are dielectrics, and the distance between the first part of the storage part and the second part of the storage part is partially different. The same effect can be obtained in the present embodiment (both-side barrier configuration).

[0023] Furthermore, the same applies to a configuration in which a part of the reservoir is a dielectric, and the distance force between the part of the reservoir and the second electrode side is partially different (a one-side barrier configuration). The effect of can be obtained.

[0024] Further, according to the present invention, the internal electrode and the external electrode provided on the outer peripheral surface of the container are used with the container made of the dielectric material interposed therebetween, and the internal electrode of the container provided with the external electrode is used. A dielectric barrier discharge is generated between the side surface and the internal electrode. Here, the interval between the inner electrode and the inner surface of the portion of the container where the outer electrode is provided is configured to be partially different. Therefore, it is possible to generate and maintain plasma by automatically selecting a region where appropriate glow plasma can be maintained according to various conditions such as pressure in the container. That is, as the pressure increases, the plasma is maintained in a region having a short interval. Accordingly, since the glow plasma can be maintained regardless of the atmospheric pressure state in the container, the pressure in the container can be set in a wide range. In addition, a container made of a dielectric material has two functions of a pressure container and a dielectric barrier, and the structure can be simplified.

[0025] If a high-frequency power source is used as a power source for the voltage applied between the two electrodes in order to generate discharge, the reservoir, which is a dielectric material existing between the two electrodes, causes the high-frequency discharge to be streamered. It functions as a direct current blocking device to maintain a glow plasma without growing into a shape. Therefore, it is easy to generate and maintain the glow plasma on a regular basis, and it is possible to generate the glow plasma over a long period of time.

[0026] Further, in addition to the above effects, if the glow plasma can be generated and maintained in a steady and stable state in a state where the liquid and the atmospheric gas are stored in the storage section, the liquid and the plasma are prolonged. Can be contacted over time. Therefore, when used as a liquid processing apparatus, the efficiency can be increased.

[0027] Further, by maintaining the internal electrode over the entire height direction of the reservoir, the electrode area can be increased, and plasma can be generated over a wide range. Also By configuring the storage part in a cylindrical shape, the distribution of the distance between the electrodes with the external electrodes provided in the periphery becomes substantially uniform, and the condition range for maintaining plasma generation can be widened.

[0028] Further, by arranging the internal electrodes so as to contact the peripheral wall of the container, the distance between the internal electrodes and the external electrodes can be made extremely small, and the range of the distance between the electrodes can be widened. That's right.

[0029] Further, according to the above configuration, since the range of the distance between the electrodes can be widened, it is possible to generate and maintain plasma over a wide pressure range of 0.01 atm. Can

[0030] Further, in order to supply the atmospheric gas from the outside into the storage unit, a usable atmospheric gas can be freely selected by using an apparatus that supplies the atmospheric gas into the storage unit. It becomes possible to select appropriately.

[0031] Further, if the atmospheric pressure in the storage part is made lower than the vapor pressure of the liquid stored in the storage part, the liquid vapor in the storage part can be used as the atmospheric gas, so Impurities are not mixed, and the configuration of the apparatus can be simplified.

[0032] Further, if the second electrode is formed in a spiral shape, in addition to the above effects, bubbles of atmospheric gas are entangled in the spiral second electrode, and a gas phase tends to exist around the second electrode, Plasma can be generated with higher efficiency. In addition, the electrode area can be increased, and plasma can be generated and maintained in a wider range.

[0033] In addition, in the above configuration, by applying a high frequency voltage of 100 MHz from ζ to the voltage application device, it becomes easier to maintain the glow plasma than the streamer discharge or the arc discharge in which it is grown.

Brief Description of Drawings

[0034] These and other objects and features of the invention will become apparent from the following description taken in conjunction with the preferred embodiments with reference to the accompanying drawings. In this drawing,

[FIG. 1] FIG. 1 is a diagram showing a schematic configuration of a glow plasma generating apparatus that works on the first embodiment of the present invention,

[FIG. 2A] FIG. 2A is a diagram showing a configuration of one chamber member used in the glow plasma generator of FIG. Is a schematic diagram showing

[FIG. 2B] FIG. 2B is a cross-sectional view taken along the line ΠΒ in FIG. 2A.

[FIG. 3A] FIG. 3A is a diagram showing a modification of the arrangement relationship between the internal electrode and the external electrode,

[FIG. 3B] FIG. 3B is a diagram showing a modification of the arrangement relationship between the internal electrode and the external electrode,

[FIG. 4] FIG. 4 is a diagram showing a configuration of a rectifier used for rectification adjustment.

FIG. 5 is a view showing another embodiment of a chamber member used in the glow plasma generator of FIG.

[FIG. 6] FIG. 6 is a cross-sectional view taken along line VI—VI in FIG.

FIG. 7 is a view showing still another embodiment of a chamber member used in the glow plasma generator of FIG.

[FIG. 8] FIG. 8 is a partially enlarged cross-sectional view of FIG.

[FIG. 9] FIG. 9 is a graph showing the relationship between time and concentration as an experimental result when methylene blue was decomposed using the glow plasma generator according to this embodiment. [FIG. 10A] FIG. 10A is a schematic view showing a modified example of one member of a chamber used in the glow plasma generator of FIG.

[FIG. 10B] FIG. 10B is a schematic diagram showing a further modification of a chamber member used in the glow plasma generator of FIG.

[FIG. 10C] FIG. 10C is a schematic diagram showing a further modification of a chamber member used in the glow plasma generator of FIG.

[FIG. 10D] FIG. 10D is a schematic view showing a further modification of one member of the chamber used in the glow plasma generator of FIG.

[FIG. 11A] FIG. 11A is a schematic view showing a further modification of a chamber member used in the glow plasma generator of FIG.

[FIG. 11B] FIG. 11B is a schematic view showing a further modification of a chamber member used in the glow plasma generator of FIG.

FIG. 12 is a schematic view showing a further modification of a chamber member used in the glow plasma generator of FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Before the description of the present invention is continued, the same reference numerals are given to the same components in the accompanying drawings. Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

[0036] FIG. 1 is a diagram showing a schematic configuration of a glow plasma generator according to a first embodiment of the present invention. The glow plasma generator 1 includes a chamber member 2 and a voltage applying device 3, and an atmosphere gas tank 4, which is an example of a gas atmosphere generation device for supplying the atmosphere gas stored in the chamber member 2. A liquid tank 5 for supplying the liquid stored in the chamber member 2 into the chamber member, a pressure gauge 7 for measuring the pressure in the chamber member 2, and adjusting the pressure in the chamber member 2 It is connected to a vacuum pump 8 which is an example of a gas atmosphere generating device for the purpose. The atmospheric gas tank 4 and the liquid tank 5 are connected to the chamber member 2 through a valve 8 so as to be openable and closable, and can supply atmospheric gas and liquid into the chamber member as necessary. The chamber member 2 may include a discharge port that can discharge the liquid stored in the inside. That is, while supplying the liquid from the liquid tank 5 and discharging the discharge loca liquid, the plasma may be generated while continuously supplying and discharging the liquid.

[0037] As shown in FIG. 2A, the chamber member 2 has a cylindrical container 10 made of a dielectric material as an example of a reservoir. In the present embodiment, a glass member having a diameter of 40 mm is used. In the present embodiment, the container 10 used as a member of the chamber is entirely made of glass, but may be configured such that a dielectric material is partially provided. For example, only a portion where an external electrode 12 described later is provided can be used as a dielectric material. The container 10 may have a prismatic shape in addition to the cylindrical shape.

The container 10 has a structure that is substantially sealed by an upper wall 13a and a lower wall 13b positioned above and below the peripheral wall 14. The upper wall 13a and the lower wall 13b may be configured by members such as lids provided as separate members on the upper and lower sides of the container, or may be configured integrally with the container 10. Further, the upper wall 13a and the lower wall 13b are not necessarily made of a dielectric material. For example, a metal or the like can be used.

[0039] Liquid and atmospheric gas can be stored inside the sealed container. Liquid and atmosphere The gas gas storage ratio is not particularly limited, but it is preferable to store about half of the capacity of the container and to use half of the gas as the atmospheric gas. The liquid 100 stored in the chamber member 2 is not particularly limited, and can store the liquid to be processed when the glow plasma generator is used in a liquid processing apparatus or the like as will be described later. As will be described later, since the liquid stores the target liquid used for liquid processing, for example, when the liquid processing is not performed, that is, when only glow plasma is generated. Need not store liquid in the container. It should be noted that, without storing liquid, as described later, according to the glow plasma generator that works on this embodiment, it is possible to generate and maintain a steady globe plasma!

[0040] The atmospheric gas 101 can be subjected to a plasma process using various gases such as a monomer gas and a reactive gas that are not particularly limited. However, since noble gases such as helium and argon have a particularly high quasi-stable excited state compared to other molecular gases, the mixed gas can be efficiently dissociated and the subsequent chemical reaction can be easily caused. . For example, water vapor generated by boiling a liquid (for example, water) stored by lowering the pressure in the container can be used as the atmospheric gas. In this case, since the atmospheric gas is supplied from the liquid tank, it is not necessary to provide a separate fuel tank.

[0041] The chamber member 2 is provided with an internal electrode 11 as an example of a second electrode arranged so as to penetrate the upper wall 13a and the lower wall 13b. The internal electrode has a circular cross-section and is composed of straight wire rods! The material of the internal electrode is not particularly limited as long as it is a metal, and can be appropriately selected according to the application. For example, tanta- sten or stainless steel that is relatively hard and resistant to corrosion can be used. Further, a material having a large secondary electron emission coefficient may be applied to the surface. The internal electrode 11 is provided at a position eccentric to the central axis of the container so as to be parallel to the central axis. Therefore, the distance in the height direction of the container 10 between the internal electrode and the inside of the peripheral wall 14 of the container 10 is the same regardless of the position in the extending direction of the internal electrode 11. On the other hand, the distance in the circumferential direction between the internal electrode and the peripheral wall of the container 10 varies depending on the circumferential direction around the internal electrode. In the present embodiment, a stainless steel wire (Φ

5 mm), and is arranged close enough to contact the inside of the peripheral wall 14. By disposing the internal electrode 1 1 in contact with the inner surface of the peripheral wall 14 of the container, the electrode The range of the distance can be widened, and the discharge path can be made very short to make it easy to generate globe plasma even at high pressure.

In addition, an external electrode 12 as an example of a first electrode is provided on the outer surface of the peripheral wall 14 of the container 10. The external electrode 12 is a plate-like electrode provided along the outer peripheral surface of the peripheral wall 14. In the present embodiment, the container is provided in an intermediate part in the height direction of the container and in a part of the peripheral wall 14 in the circumferential direction over a half circumference. When the external electrode is partially provided, it is preferable that at least a part of the electrode is arranged so as to be higher than the liquid level of the liquid stored in the container 10. The external electrode may be provided over the entire circumference of the peripheral wall 14 in the circumferential direction, or may be provided over the entire height direction of the container 10. By providing the external electrode 12, the distance between the internal electrode 11 and the external electrode 12 is continuously distributed.

[0043] The positional relationship between the internal electrode 11 and the external electrode 12 is shown in FIG. 2B. 2B is a cross-sectional view taken along line ΠΒ-ΠΒ in FIG. 2A. In the present embodiment, the external electrode 12 covers a part (dielectric part) of the container 10. Between the external electrode 12 (first electrode) and the internal electrode 11 (second electrode), at least a part of the atmospheric gas and at least a part of the container 10 (reservoir) are interposed. The internal electrode 11 is disposed so as to be positioned near the end of the external electrode 12. By arranging both electrodes in this way, the distance between the electrodes is changed from a very short distance (closely in the shortest state) as shown by symbol A to a long distance (maximum at maximum) as shown by symbol B. Various electrode distances can also be realized, up to approximately the diameter of the container 10). As described above, since the range of the distance between the inner electrode and the inner electrode can be widened for each portion of the outer electrode, a steady glow plasma can be generated and maintained under various conditions as described later.

Note that the interelectrode distance in the present embodiment refers to the distance between the internal electrode 11 and the inner side surface of the peripheral wall of the container 10 (at least a part of the atmospheric gas) rather than the distance between the internal electrode and the external electrode. It is essential to mean the distance between the outer electrode 12 side and the inner electrode 11 side of the existing region. Details will be described later.

[0045] As described above, the glow plasma generator that works on the first embodiment of the present invention has been described with reference to FIGS. 1, 2A, and 2B. In the glow plasma generating apparatus according to the first embodiment of the present invention, the container 10 corresponds to the “reservoir”, and the dielectric portion of the container 10 corresponds to the “dielectric portion of the reservoir”. The external electrode 12 corresponds to the “first electrode”, and the internal electrode 11 corresponds to the “second electrode”. Further, the distance between the side of the external electrode 12 and the side of the internal electrode 11 (symbol A, symbol B shown in FIG. 2B) of at least a part of the atmospheric gas is partially different.

Note that the glow plasma generator of the first embodiment of the present invention is not limited to the contact between the external electrode 12 and the dielectric portion of the container 10. Between the external electrode (first electrode) and the internal electrode (second electrode), at least a part of the atmospheric gas and the dielectric part of the container 10 (reservoir) are interposed. As long as the distance between the first electrode side and the second electrode side is partially different, the external electrode 12 and the induction portion of the container 10 may be non-contact.

[0048] Furthermore, it is not limited that all of the container 10 is a dielectric. As long as at least a part of the atmospheric gas and at least a part of the container 10 are interposed between the external electrode and the internal electrode, at least a part of the container 10 may be a dielectric part.

FIG. 3A and FIG. 3B show a modification of the arrangement relationship between the internal electrode and the external electrode. In FIG. 3A, the external electrode 12 is arranged over the entire circumference of the container 10 and two internal electrodes 11 are used. In this example, the range of the distance between the electrodes can be widened, but the surface area ratio between the internal electrode and the external electrode is greatly different, so that a plurality of internal electrodes are used and a large number of discharge paths are secured. In FIG. 3B, the external electrode is provided about half a circumference with respect to the circumferential direction of the container 10, but the internal electrode 11 is located in the circumferential intermediate portion of the external electrode 12. As a result, the range of the distance between the electrodes cannot be widened, but it is possible to take discharge paths that are separated by the same distance between the electrodes in various directions with respect to the internal electrodes, thereby generating more plasma. be able to.

The voltage application device 3 is a power source 3 for supplying high frequency power to the internal electrode 11 and the external electrode 12. In this embodiment, 13.56 MHz is used because of the usable frequency, and high frequency power of 20-100 W and 1000 V is used. The frequency used as a high-frequency power supply is preferably about 10 kHz to 100 MHz, and if it deviates significantly from these ranges, it may easily adversely affect the generation of steady glow discharge. . Further, as will be described later, the glow plasma generator 1 which is effective in this embodiment can also generate glow plasma in a state where the liquid phase and the gas phase coexist, and the water content of the liquid phase can be generated. Since the load inductance of the high frequency power supply changes due to the influence, it is preferable to perform rectification adjustment.

[0051] Fig. 4 shows the configuration of a rectifier used for rectification adjustment. In order to efficiently apply the energy output from the high-frequency power supply 30 to the electrode serving as a load, it is necessary to match the impedance of the load with the impedance of the power supply. If the matching is V ヽ, all energy is not consumed by the load, but is reflected and returned to the high frequency power supply 30. This is not only inefficient in energy but can also lead to destruction of the power supply. For this purpose, a reactance component of the load can be obtained by inserting a matching box that also includes lossless circuit element force, such as variable capacity capacitors 33, 34 and variable capacity coil 32, between the high frequency power supply and the load. Is canceled and impedance matching is performed. The output terminal 36 for the matching box force is connected to the electrode of the chamber member 2.

[0052] Next, the operation of the glow plasma generating apparatus that works according to the present embodiment will be described. As described above, the glow plasma generating apparatus 1 that is effective in the present embodiment is characterized in that the distance between the internal electrode and the internal electrode has a different configuration depending on the location of the external electrode. A voltage is applied between both electrodes by voltage application device 3. At this time, since the distance between the electrodes has a distribution and is not constant as described above, the distance between the rod-shaped internal electrode and the inner surface of the container where the external electrode is provided depends on the pressure state in the chamber member. Thus, a discharge path is determined spontaneously, and a dielectric barrier discharge is generated from the determined specific discharge path.

[0053] The generated discharge is generated between the inner electrode and the inner surface of the peripheral wall of the container in contact with the outer electrode. The force is in a DC-insulated relationship. The container, which is a dielectric material, is brought into a high electrical energy state by the external electrode, and the dielectric barrier discharge is generated. Therefore, the distance between the electrodes in this embodiment is not the distance between the internal electrode and the external electrode, but the distance between the internal electrode and the inner surface of the peripheral wall of the container that touches the external electrode (atmospheric gas). Is essentially the distance between the external electrode side and the internal electrode side of at least a part of the above. The generated barrier discharge is the globe It spreads in the region of the discharge path with a distance between the electrodes that can be maintained as a laser, and discharge is continuously performed over the region.

[0054] That is, it is considered that a Paschen condition that is a condition for starting a discharge is generally required as a requirement for generating a plasma discharge. Although this law is not completely satisfied under special conditions such as high-pressure discharge under high pressure, the discharge starting voltage is minimized when the product of the pressure and the distance between electrodes is a certain value. That is, for example, the distance between the electrodes needs to be extremely small under high atmospheric pressure such as atmospheric pressure. Therefore, since the glow plasma generator that is useful in this embodiment has a wide range of distances between the electrodes, the conditions for starting the discharge are automatically selected, and the discharge generated in the selected discharge path gradually increases. It spreads. Therefore, it is possible to maintain the steady generation of glow plasma in a wide, wide, and range from a high vacuum state where plasma is generally generated to a high pressure state. Specifically, a glow plasma can be generated and maintained constantly under conditions of about 0.01 to 10.0 atm.

[0055] According to the above-mentioned Passing Law, in order to start discharge with an appropriate applied voltage under atmospheric pressure, the distance between the electrodes needs to be in the millimeter order, and the plasma becomes extremely small. Therefore, in the Glow Discharge Disclosure, the plasma is ignited by the pump 6 with the pressure inside the container 10 slightly lowered, and then the atmosphere gas is supplied from the atmosphere gas tank 4 to increase the gas pressure. Even so.

It should be noted that the glow plasma generator that works in the present embodiment has an advantage that it can constantly generate glow plasma in a wide pressure range. Therefore, it is preferable to appropriately design the chamber member 2 according to the purpose based on the property that the distance between the electrodes that can be maintained as a glow plasma varies depending on various conditions such as the pressure inside the chamber member 2. For example, if the diameter of the container 10 is increased, the range of the distance between the internal electrode and the external electrode is naturally widened. Therefore, a large amount of plasma can be generated using the large container if the purpose is to be used only in an environment where the atmospheric pressure is low so that the glow plasma can be generated even at the large distance between the electrodes. However, if it is intended to be used at high pressures near atmospheric pressure, even if a large vessel is used, plasma can only be discharged through a part of the discharge path, and as a result, one plasma in the vessel can be obtained. Plasma only in the department May not occur. Even in this case, it is possible to lengthen the discharge path by adjusting the amount of high-frequency power.

[0057] In addition, the glow plasma generator according to the present embodiment has an internal electrode that is wide and wide in the height direction in the container 10, and is therefore very close to the liquid level of the liquid in the container. Plasma is generated over a wide area in the height direction of the container, that is, a wide area in the gas phase in contact with the liquid phase. Therefore, for example, by lowering the atmospheric pressure in the container 10, the liquid 10 in the container boils and the internal electrode 11 is partially wetted. Even when the plasma is extinguished, the glow plasma spreads and is maintained by the discharge generated by the partial force of the internal electrode not wetted. Therefore, even if the electrode is somewhat wet, the discharge can be maintained and the glow plasma can be maintained, which is advantageous when used for plasma treatment to liquids. Therefore, the development of new plasma processes for plasma chemistry and bioscience can be expected.

FIG. 5 is a view showing another embodiment of a chamber member used in the glow plasma generator of FIG. Unlike the chamber member shown in FIGS. 2A and 2B, the chamber member 2A is supplied while flowing the liquid in a state where the atmosphere gas is published in the liquid that does not store the liquid in the container. The configuration is such that glow plasma is generated in the atmospheric gas phase in the container.

[0059] The chamber 1A 2A shown in FIG. 5 is composed of a cylindrical container 10a made of a dielectric material arranged in the horizontal direction. The liquid is continuously supplied from the right side in FIG. 5 to the container 10a and flows to the left side in the figure. It is preferable to prevent the liquid flow at this time from becoming laminar. For example, a baffle plate is provided in the container to disturb the liquid flow.

[0060] The container 10a is connected to an atmosphere gas supply pipe 16 for supplying an atmosphere gas, and the atmosphere gas is supplied into the container 10a from a nozzle 17 provided at the end of the atmosphere gas supply pipe 16. Further, since the nozzle is provided on the lower surface of the container 10a, the liquid is easily disturbed by bubbles of the atmospheric gas. In FIG. 5, the nozzle 17 is provided only at one location. However, a plurality of nozzles 17 may be provided, and a large number of fine bubbles are generated. A hole nozzle or various bubblers may be used. Examples of bubblers include those that stir bubbles with a probe, those that use lapar nozzles, and those that create microbubbles using the shearing force of fluid. Increasing the number of bubbles discharged into the liquid disturbs the flow of the liquid, and can increase the contact between the plasma and the liquid in the plasma processing described later.

[0061] Inside the container 10a, an internal electrode 11a is arranged along the extending direction of the container. The internal electrode 11a is provided on the upper side with respect to the center of the container 10, specifically, at the highest position on the inner wall of the container 10a so as to extend in parallel with the central axis, and is provided through the container 10a. Connected to the outside through hole 18.

[0062] Further, an outer electrode 12a, which is a plate-like electrode provided along the outer peripheral surface, is provided on the outer peripheral surface of the container 10a. The external electrode 12a is disposed so as to cover the outer peripheral surface 14 at a position where the internal electrode 11a is provided. In the present embodiment, the internal electrode 11a is located at an intermediate position between the external electrodes. In addition, the external electrode is provided on a part of the peripheral wall 14 in the circumferential direction of the container 10a over a half circumference. The external electrode 14a may be provided over the entire circumference of the peripheral wall 14 in the circumferential direction of the container 10a! /.

FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. In the present embodiment, the liquid 100 flows in the container 10a, that is, the atmosphere gas from the nozzle 17 is upstream of the internal electrode 11a in the liquid supplied to the container 10a. Is supplied, becomes bubbles 102 in the liquid 100, and flows in the container as the liquid 100 flows.

[0064] Also in the present embodiment, the interelectrode distance from the internal electrode 11a is characterized in that it has a different configuration depending on the location of the external electrode 12a. When a voltage is applied between the two electrodes by the voltage application device 3, the distance between the electrodes is not constant as described above. Therefore, the outer surfaces of the rod-shaped internal electrode 11a and the container 10a are changed according to the pressure state in one member of the chamber. A discharge path is spontaneously determined between the external electrodes 12a provided along the line, and a dielectric barrier discharge is generated from the determined specific discharge path.

[0065] In the present embodiment, the pressure in the container 10a is substantially equal to the atmospheric pressure, so it is difficult for a portion having a large interelectrode distance to be a discharge path. Therefore, bubble size It is preferable that the bubble 102 of this size exists between the electrodes. Therefore, it is preferable to reduce the diameter of the container 10a so that the surface of the liquid flowing in the container 10a contacts the glow plasma. Specifically, the inner diameter of the container 10a is preferably kept at about φ20 mm.

[0066] The glow plasma apparatus according to the present embodiment can generate and maintain glow plasma in a steady manner inside the bubbles present in the container. In addition, since it is preferable to reduce the bubble size as described above, the contact area between the gas phase and the liquid phase can be increased, which is advantageous when used for applications such as plasma treatment to liquids.

Note that the glow plasma generator according to the present embodiment allows the liquid phase to flow only in a part of the inside of the container so that the gas phase exists around the internal electrode 11a in the container. Can also be used. In this case, since the internal electrode 11a is provided extending in the direction of the central axis in the container 10a, the internal electrode 11a is partially wetted, and as a result, the supply of secondary electrons from the electrode surface is reduced. As a result, even if the plasma in the relevant part is extinguished, the glow plasma is spread and maintained by the discharge generated by the partial force that is not wetted of the internal electrode. Therefore, even if the electrode is slightly wet, the discharge can be maintained and the globular plasma can be maintained, which is advantageous when used for applications such as plasma treatment to liquids. Therefore, the development of new plasma processes for plasma chemistry and bioscience can be expected.

[0068] FIG. 7 is a diagram showing a schematic configuration of a glow plasma generator according to the second embodiment of the present invention. This glow plasma generator includes a chamber member 2B. Similarly to the one chamber member shown in FIG. 5, the one-chamber member 2B supplies the liquid and the atmospheric gas in a mixed state while flowing and supplies the globe plasma into the atmospheric gas gas phase in the container. It is the structure which is generated.

[0069] The chamber apparatus 2B in FIG. 7 includes a cylindrical container 10b made of a dielectric material arranged in a vertical direction. In FIG. 7, an atmospheric gas supply pipe 22 that supplies atmospheric gas from the lower side and a liquid supply pipe 24 that supplies liquid are connected to the inside 10b of the container. At the end of the atmosphere gas supply pipe 22, a fine nozzle 23 is provided to form fine bubbles in the liquid supplied from the liquid supply pipe 24. For forming bubbles in the liquid The configuration is not limited to the single nozzle 23, and various configurations used as a bubbler can be used. Examples of bubblers include those that stir bubbles with a propeller, those that use a rubber nozzle, and those that create microbubbles using the shearing force of a fluid.

[0070] The internal electrode unit 20 is disposed in the container 10b. The internal electrode unit 20 has a structure in which the internal electrode Lib is fixed in a spiral manner along the outer peripheral surface of a rod-shaped support member 19 made of a dielectric material. The internal electrode unit 20 preferably has an outer diameter dimension substantially equal to the inner diameter of the container 10b. Specifically, it may be designed such that the sum of the outer dimensions of the support member 19 and the diameter of the wire constituting the internal electrode l ib is approximately equal to the inner diameter of the container 10b. A space formed between the container 10b and the support member 19 of the internal electrode unit is a flow space 20 in which the liquid and the atmospheric gas supplied to the container 10b flow as described above.

[0071] In the present embodiment, since the internal electrode is configured using a metal rod having a circular cross section, the interelectrode distance with the external electrode is different from the circumferential direction of the internal electrode 1 lb. . That is, the distance between the electrodes is the shortest at the location where the internal electrode l ib is in contact with the inner peripheral surface of the container 10b, and the distance between the electrodes with the external electrode 12b increases as the positional force also increases in the vertical direction. Constructed. As described above, the distance between the electrodes is configured to have a range for each portion of the external electrode, and as described above, the distance between the electrodes is provided along the outer peripheral surface of the internal electrode and the container according to the pressure state of the gas phase. A discharge path is spontaneously determined between the external electrodes, and a dielectric barrier discharge is generated from the determined specific discharge path.

[0072] As in the case described with reference to FIG. 1, FIG. 2A, and FIG. 2B, in the description of the glow plasma generator that works on the second embodiment of the present invention, The distance between the internal electrode and the inner surface of the peripheral wall of the container rather than the distance between the internal electrode and the external electrode (the distance between the external electrode side and the internal electrode side of at least a part of the atmosphere gas) It is essential to mean.

[0073] In addition, an outer electrode 12b, which is a plate-like electrode provided along the outer peripheral surface, is provided on the outer peripheral surface of the container 10b. The external electrode is at the position where the internal electrode 11a is provided. It arrange | positions so that an outer peripheral surface may be coat | covered. In the present embodiment, the inner electrode l ib is provided on a part of the peripheral wall 14 in the circumferential direction of the container 10a so as to cover the height direction region of the container 10b, and is provided over about a half circumference. The external electrode 14b may be provided over the entire circumference of the peripheral wall 14 in the circumferential direction of the container 10b! /.

FIG. 8 is a partially enlarged cross-sectional view of FIG. The liquid and the atmospheric gas supplied into the container 10b rise through the flow space 21. At this time, since the bubbles 102 of the atmospheric gas 101 rise while entangled with the internal electrode l ib, the surroundings of the internal electrode l ib tend to be in a gas phase. Further, since the internal electrode l ib is circular in cross section, the distance from the inner peripheral surface of the container 10b differs in the circumferential direction. In this state, when a high frequency voltage is applied from the voltage application device 3 between the internal electrode l ib and the external electrode 12b, the internal electrode l ib and the outer peripheral surface 14 of the container 10b according to the pressure state in the gas phase. A discharge path is spontaneously determined between the external electrodes 12b provided along the line, and a dielectric barrier discharge is generated from the determined specific discharge path.

[0075] The generated discharge is generated between the inner electrode and the inner surface of the peripheral wall of the container in contact with the outer electrode. The force is in a DC-insulated relationship. The container, which is a dielectric material, is brought into a high electrical energy state by the external electrode, and the dielectric barrier discharge is generated. The generated barrier discharge spreads in the region of the discharge path having a distance between the electrodes that can be maintained as a glow plasma, and discharge is continuously performed in the region. With reference to FIG. 7 and FIG. 8, a glow plasma generating apparatus provided with an internal electrode having a curvature has been described. Since the atmosphere gas and liquid flow through the internal electrode with curvature, the reaction efficiency increases.

[0076] Further, in the glow plasma generator according to the present embodiment, since the internal electrode rib is in the container 10b and the electrode area is large, the plasma is generated over a wide area in the gas phase. appear. The gas phase is in contact with the liquid, and the liquid and the plasma come into contact with each other. Therefore, even if the electrode is somewhat wet, the discharge can be sustained and the glow plasma can be maintained, and the contact area between the gas phase and the liquid phase can be increased. This is advantageous when used in Therefore, it is possible to supply radicals, high-energy atoms, ultraviolet rays, etc. into water-soluble substances when the plasma comes into contact with the liquid, and new developments in plasma chemistry, biosciences, etc. are expected to develop plasma processes. so wear. The glow plasma generator that is useful in this embodiment can generate plasma even when the pressure inside the container is high, and is also compatible with biological materials and the like because it does not require evacuation.

[0077] By performing discharge using the glow plasma generator having the configuration of one chamber member that is effective in each of the above embodiments, a glow discharge is realized on the liquid surface and in the liquid. It is possible to supply energy uniformly in various forms to the liquid. As a result, it has become possible to perform a plasma process for chemical reactions in liquids, which has been difficult in the past, and new technological developments are expected.

[0078] As described above, referring to FIGS. 2A, 2B, 3A, 3B, 5 to 8, 10A to 10D, 11A, and 11B, an internal electrode is provided inside the container, In the above description, the external electrode is provided outside the container.

[0079] However, in the present invention, the position force of each of the two electrodes is not limited to being positioned inside and outside the container. At least part of the atmospheric gas and the dielectric part of the container (reservoir) are interposed between one (first electrode) and the other (second electrode) of the two electrodes. As long as the distance between the first electrode side and the second electrode side of the part is partially different, the two electrodes may be located outside the container, or located inside the container. May be.

FIG. 12 shows one embodiment of the present invention (glow plasma generator 120). The glow plasma generator 120 includes a first electrode 102, a second electrode 104, and a container 106. An atmosphere gas is stored inside the container 106. The first electrode 102 and the second electrode 104 are provided outside the container 106.

[0081] The container 106 has a first portion 108 and a second portion 110. The first portion 108 and the second portion 110 of the container 106 are dielectrics.

[0082] The first electrode 102 is provided so as to cover at least a part of the first part 108 of the container 106, and the second electrode 104 is provided so as to cover at least a part of the second part 110 of the container 106. It is provided.

[0083] Between the first electrode 102 and the second electrode 104, at least a part of the atmospheric gas and the first portion 108 and the second portion 110 of the container 106 are interposed. In addition, the wall of the first part 108 of the container 106 The thickness varies depending on the location. The wall thickness of the second part 110 of the container 106 does not vary depending on the location. The first electrode 102 and the second electrode 104 are parallel to each other. As a result, the distance between the side 108a of the first electrode 102 and the side 110a of the second electrode 104 of the container 106 is partially different.

[0084] For example, from a very short distance (closely in the shortest state) as indicated by reference symbol C to a long distance as indicated by reference symbol D (maximum, it can be made substantially equal to the width dimension of the container 10). Up to this point, the distance between the side 108a of the first electrode 102 and the side 110a of the second electrode 104 of the container 106 can be configured to be partially different.

[0085] As a result, the range of the distance between the first electrode 102 side 108a and the second electrode 104 side 110a of the container 106 is widened, and a steady glow plasma is generated and maintained under various conditions. Can have.

Example

[0086] In order to evaluate the chemical reactivity of water contact plasma as a performance evaluation when the glow plasma generator using the chamber apparatus shown in FIGS. 2A and 2B is used as a plasma processing apparatus, methylene blue was used. (Dye) decomposition experiment was performed in water contact plasma. Methylene blue is suitable for quantitative evaluation because it is not decomposed by ultraviolet light and its concentration can be easily measured optically. The experimental conditions are as follows.

[0087] Using the apparatus shown in Figs. 2A and 2B, an aqueous solution in which methylene blue was dissolved at an initial concentration of 20 gZml as a liquid phase was stored in a container, and helium was used as an atmospheric gas at 0.1 atm. A high frequency voltage of 13.56 MHz, 80 W, 2000 V was applied from the voltage application device. Glow plasma was generated between the internal and external electrodes, and plasma in contact with the liquid phase surface was confirmed. The voltage application was stopped every 10 minutes, the methylene blue solution was sampled, and the concentration of the methylene blue solution was measured with a spectrophotometer. The result is shown in Fig. 9.

[0088] As shown in FIG. 9, it was confirmed that the concentration of methylene blue decreased exponentially with time. It can be inferred that by irradiating the aqueous solution with plasma, water molecules decompose and OH radicals with strong and oxidizing power are generated, which destroys (oxidizes) the benzene ring of the Cyan blue.

As described above, according to the glow plasma generator that works on the present embodiment, the liquid is It is possible to create a Xinjiang reaction field that is in contact with ma. Examples of the application range of the plasma process include biopolymers. Since biopolymers are inseparable from the water environment, it has been difficult to apply the low-pressure plasma process that is performed under the conventional vapor pressure. Since the glow plasma generator that works in this embodiment can generate plasma in a controllable form at atmospheric pressure, the glow plasma can be brought into constant contact with water over a long period of time. A plasma process for liquids can be performed.

Note that the present invention is not limited to the above-described embodiment, and can be implemented in various other modes. For example, in the above embodiment, the wall thickness of the container made of the dielectric material is constant, and the distance between the electrodes (at least part of the atmosphere gas of the external electrode is set by shifting the position of the internal electrode from the center). The distance between the inner electrode and the side of the internal electrode) The distance between the internal electrode and the surface of the container by changing the wall thickness of the container The distance between the electrode side and the internal electrode side) may be different. For example, as disclosed in FIG. 10A, the internal electrode 1 lc and the external electrode 12c are plate electrodes arranged in parallel to each other, and the wall 22c wall thickness of the container 10c arranged therebetween is partially different. Accordingly, the distance between the internal electrode (the internal electrode side of the atmospheric gas) and the inner surface 23c of the container (the external electrode side of the atmospheric gas) can be made different. As a result, the distance between the internal electrode and the inner surface 23c of the container has a distribution.

In addition, as shown in FIG. 10B, a plate-like external electrode 12 d may be provided along the outer wall of the container 10 d having a rectangular cross section, and a plate-like internal electrode may be provided diagonally in the container interior 25. .

Furthermore, as shown in FIG. 10C, a container 10e having the same configuration as the container 10 used for the chamber member 2 shown in FIG. 2A is used, and the internal electrode l ie is also inclined with the central axial force of the container 10e. It may be arranged. Further, as shown in FIG. 10D, a container 10f having a configuration similar to that of the chamber partial member 2 shown in FIG. 2A may be used, and the external electrode 12f provided intermittently in the circumferential direction may be provided over the entire circumference. . By providing the external electrode 12f intermittently, the interelectrode distance between the internal electrode 1 If and the external electrode 12f (distance between the external electrode 12f side of the atmospheric gas and the internal electrode 1 If side) is discrete. Distributed. [0093] One chamber member as shown in FIG. 11A and FIG. 1IB may be used. Similar to the chamber member 2b shown in FIG. 7, this chamber member is configured to allow liquid and bubbles to flow inside. Specifically, the inside of a flat container 10g having a rectangular cross section is defined as a flow space 2 lg of bubbles of liquid and atmospheric gas, and a bent wire-like internal electrode l lg is disposed in the flow space 2 lg. The plate-like external electrode 12g is provided along the outer peripheral wall of the container 10g. The diameter of the internal electrode 1 lg is configured to be approximately equal to the width in the short direction of the flow space 21g. Bubbles sent together with the liquid into the flow space 21g are entangled with the internal electrode l lg, and the periphery of the internal electrode l lg is a gas phase. It becomes easy to become.

As described above, according to the glow plasma generating apparatus of the present invention, depending on the shape of the internal electrode itself, the location of the internal electrode, the location of the external electrode, or a combination of these plural configurations. The distance between the internal electrode and the inner periphery of the container is partially different. Therefore, it is possible to spontaneously select the distance between the electrodes according to the use environment and start the discharge, and then the glow plasma can be widened and constantly maintained in the region.

Industrial applicability

[0095] The glow plasma generator according to the present invention can generate glow plasma even when the pressure in the container is high, and the glow plasma can be brought into contact with a liquid. With the availability of For example, it can be suitably used as a sterilization apparatus that sterilizes precision medical instruments and the like using hydroxy radicals generated by contact with plasma water. In addition, since each chamber member can be realized in a small size, it is possible to process a large amount of liquid by modularly arranging the chamber members in series or in parallel. You can select the process. Further, by circulating using a fluid pump, the target liquid can be continuously processed, and can be suitably used for a circulating water treatment apparatus. It can also be used to synthesize biopolymers with new functions. For example, in a chemical polymer synthesis method, it is also possible to carry out polymerization using force plasma that requires a specific reactive group such as a double bond in a monomer as a starting material. By using this device, functional polymers containing biochemical substances in aqueous solutions are synthesized by polymerizing monomers in the liquid. According to this device, under atmospheric pressure, And since the rise in Balta temperature is small, it has the potential to develop biomaterials with new functions that have very good affinity with biological materials.

[0096] It should be noted that by appropriately combining any of the various embodiments described above,

, Each effect can be achieved.

[0097] Although the present invention has been fully described in connection with preferred embodiments with reference to the accompanying drawings, various changes and modifications will be apparent to those skilled in the art. Such changes and modifications are to be understood as being included therein, so long as they do not depart from the scope of the present invention as defined by the appended claims.

Claims

The scope of the claims

[1] A glow plasma generator comprising a reservoir configured to store an atmospheric gas, a first electrode, and a second electrode,

At least a part of the storage part is a dielectric part made of a dielectric,

A glow plasma generating apparatus, wherein a distance between the first electrode side and the second electrode side of the at least part of the atmospheric gas is partially different.

[2] The dielectric part of the storage part has a first part and a second part,

2. The glow plasma generating apparatus according to claim 1, wherein the distance between the first part of the storage part and the second part of the storage part is provided so as to be partially different.

[3] The first electrode is provided so as to cover the dielectric portion of the reservoir,

2. The glow plasma generating device according to claim 1, wherein a distance between the dielectric portion of the storage portion and the second electrode side is partially different.

[4] The storage section has a partition wall that defines an inside for storing the atmospheric gas and an outside for not storing the atmospheric gas,

The said 1st electrode is provided in the exterior side of the said partition wall of the said storage part, The said 2nd electrode is provided in the interior side of the said partition wall of the said storage part. Glow plasma generator.

[5] The second electrode is provided at a position eccentric from the inner center of the reservoir. The glow plasma generator according to claim 4.

6. The glow plasma generating apparatus according to claim 4, wherein the second electrode has a spiral shape.

7. The glow plasma generating apparatus according to claim 4, wherein the second electrode is in contact with an inner side surface of the partition wall of the storage section.

8. The glow plasma generator according to claim 1, wherein the distance between the first electrode side and the second electrode side is partially different so as to be distributed continuously. .

9. The glow plasma generator according to claim 1, wherein the distance between the first electrode side and the second electrode side is partially different so as to be distributed discretely. .

[10] The globe plasma generating apparatus according to [4], wherein the storage section is configured to store a liquid.

[11] A method of generating glow plasma by a glow plasma generator,

The glow plasma generator comprises:

The glow plasma generation method includes:

Including a discharge generating step of generating a discharge between the first electrode side and the second electrode side by applying a voltage between the first electrode and the second electrode. Plasma generation method.