JP5063622B2 - Silent discharge type plasma generator and method of quenching in silent discharge type plasma generator - Google Patents

Description

  This invention is a large-capacity plasma device using silent discharge, in particular, quickly extinguishing arc discharge generated due to a short circuit between electrodes caused by electrode breakage, etc., without stopping the entire device system, The present invention relates to a silent discharge plasma generator having a new short-circuit protection function that does not use a fuse capable of restarting the apparatus, and a method for extinguishing the apparatus.

  A fuse is generally used for short circuit protection of a silent discharge plasma apparatus typified by an ozone generator. In addition, a superposition system in which a software protection function on the control surface is added to the hardware protection function of the fuse is also employed in cooperation with the short circuit protection control on the drive power source side. However, the fuse used in the plasma device is a special fuse for high voltage, and its size and cost have been a major obstacle to downsizing and cost reduction of the device.

  In the following Patent Document 1, a plasma apparatus as described above is proposed that includes a new short-circuit protection system that does not use a fuse. The system will be described below using an ozone generator as an example. FIG. 14 is a cross-sectional view of a pair of electrode portions of a cylindrical multi-tube ozone generator. In an actual apparatus, a plurality of electrode portions shown in FIG. 14 are connected in parallel in the vertical direction and depth direction of the paper surface of FIG. A source gas containing oxygen is introduced into a space formed between a metal ground electrode 1 and a dielectric (glass tube) 3 having a thin film high voltage electrode 2 having a thickness of 100 μm or less on the inner surface; and Silent discharge plasma is generated by applying a high voltage between both electrodes. This space is referred to as a discharge space 4, in which oxygen molecules are dissociated by collision with electrons and generate ozone.

  The most important feature of this conventional device is that the thin film high voltage electrode 2 formed on the inner surface of the glass tube 3 is generally thick and has a strong adhesion to the glass tube from the viewpoint of ensuring high conductivity. However, it is a conductive thin film contrary to the common sense. For example, in a general cylindrical multi-tube ozone generator having a thick film high voltage electrode, when a glass tube breaks during normal ozone generation, an arc discharge occurs between the ground electrode 1 and the thick film high voltage electrode. Short circuit between the electrodes occurs. This arc discharge lasts as long as the electrode is present and as long as both electrodes are within a predetermined insulation distance, and arc energy continues to be injected into the electrode.

  However, in the above-mentioned conventional apparatus, since the high voltage electrode is formed of a thin film, the high voltage electrode itself is provided so as to secure a sufficient insulation distance for instantaneously stopping the arc discharge by heat input by the arc discharge. It disappears by evaporation or sublimation. That is, the high voltage electrode itself detects the short-circuit phenomenon and recovers the insulation between the electrodes by eliminating the short circuit phenomenon.

  Moreover, in the structure of the said conventional apparatus, since the insulation between electrodes is automatically recovered after the occurrence of a short circuit, the ozone generating apparatus can be restarted without stopping the ozone generating system. Furthermore, as a matter of course, a normal glass tube can continue to generate ozone again at a portion other than the damaged portion even in a broken glass tube. Once a short circuit is detected and the fuse is blown, the fuse cannot be reused, and the glass tube connected to the blown fuse can never contribute to the generation of ozone. It can be said that it has an excellent short-circuit protection / restart function exceeding

  In addition, when a large-capacity ozone generator, that is, when the number of electrodes becomes enormous, there may be a case where the short-circuit current becomes extremely large. It is effective to build a protection system with protection functions superimposed. As described above, the use of the thin-film high-voltage electrode 2 eliminates the need for a fuse that has been indispensable for short-circuit protection, thereby realizing a highly reliable short-circuit protection system and reducing the size and cost of the apparatus.

  In FIG. 14, 5 is a cooling water passage, 7 is a power supply member, and 8 and 9 are tube sheets.

International Publication No. WO2006 / 103945 Pamphlet

  The conventional device as described above provides a short-circuit protection system that does not use a fuse due to the self-disappearance of the thin-film high-voltage electrode. When the short-circuit current is large, the drive power supply side The advantage of superimposing the short-circuit protection function is provided. However, when the short-circuit current becomes a large current of several tens to several hundreds A, the above configuration may not realize sufficient short-circuit protection. In this case, the arc energy injected into the electrode portion becomes extremely large, and the amount of disappearance of the thin film high voltage electrode increases.

  A large amount of evaporated and sublimated fine particles of the thin-film high-voltage electrode give conductivity to the gas in the glass tube, and the arc generated by the short circuit is formed by the disappearance of the thin-film high-voltage electrode through this conductive gas as a route. Even if the insulation distance is secured, the arc is not extinguished, and the metal power supply member (installed outside the discharge space) 7 is continuously reached from the damaged portion (arc generation start point). When the arc reaches the power supply member, the ozone generator is completely short-circuited, and the ozone generating system is stopped and the electrode part that has caused the short-circuit is forced to be replaced.

  Here, arc generation and arc extinction in a cylindrical multi-tube ozone generator (electrode constituent members are formed concentrically and coaxially) will be specifically described with reference to FIGS. When the dielectric (glass tube) 3 breaks at the breakage point 21, a pinhole-like through hole is formed at the breakage point. However, depending on the material of the dielectric 3 and the magnitude of the arc energy injected at the time of breakage, not only pinholes but also secondary breakage such as cracks and cracks may occur. The reason why the electrode of the ozone generator is damaged during operation is that the temperature rises excessively, mechanical stress generated when the dielectric 3 is inserted into the ground electrode 1, scratches generated in the dielectric 3, and manufacturing. It is conceivable that the dielectric breakdown strength of the dielectric 3 generated due to the contained defects is reduced.

  Thus, when the dielectric 3 is damaged, an arc discharge is instantaneously generated between the ground electrode 1 and the thin film high voltage electrode 2 disposed on the inner surface of the dielectric 3, and a short-circuit current flows between the electrodes. When the short-circuit current is small, as shown in FIG. 15, the thin-film high-voltage electrode 2 around the damaged portion 21 is instantly evaporated and sublimated by energy injection by arc discharge and disappears automatically. This disappearance range disappears so as to secure a sufficient insulation distance L to extinguish the arc discharge, the insulation between the electrodes is instantaneously restored immediately after the short circuit, and normal ozone generation is resumed at other than the damaged portion 21. The This is disclosed in Patent Document 1 described above.

  On the other hand, as shown in FIG. 16, when the short-circuit current is several tens of A or more, the energy injected by the arc discharge increases, so the range of the thin-film high-voltage electrode 2 that self-disappears is expanded. Further, the space where the thin film high voltage electrode 2 disappears (inside the dielectric 3) is filled with the conductive gas 22 containing the evaporated and sublimated thin film high voltage electrode fine particles, and the inside of the dielectric 3 is conductive. Space. Therefore, the insulation cannot be recovered instantaneously as shown in FIG. 15, and arc discharge continues using the conductive gas as a medium. The sustained arc continues to evaporate and sublimate the thin-film high-voltage electrode 2 and eventually reaches the power supply member 7 and may cause a complete short circuit (stop of the ozone generation system). And bulk metal with sufficient heat capacity).

  In FIG. 16, in order to superimpose the short-circuit protection function on the drive power supply 6 side on the self-extinguishing effect of the thin-film high-voltage electrode 2 and extinguish the arc, the inverter power supply It is necessary to shut off the gate signal and issue a stop command. However, in the control sequence related to the short circuit protection in the drive power supply 6, the processing time is generally required to be about 100 msec. In particular, when a short circuit occurs at a location very close to the power supply member 7, the gate signal is about 10 msec. If the power supply member 7 is not cut off, the arc reaches the power supply member 7 despite the fact that the power supply member 7 is installed outside the discharge space 4 separated from the end portion of the ground electrode 1 by the insulation distance L or more. The occurrence of an arc, that is, the occurrence of a short circuit, can be easily detected by a decrease in the output voltage. However, unless the processing time can be increased, the arc can be detected after the decrease in the output voltage is detected until the gate is shut off. Is sufficiently sustained and reaches the power supply member 7. That is, the arc may not be extinguished even if the short-circuit protection function on the drive power supply 6 side is superimposed.

  As described above, the thin-film high-voltage electrode itself self-dissipates only the amount corresponding to the insulation distance necessary for arc extinction, and the short-circuit protection function on the drive power supply side is superimposed, even when trying to restore insulation between the electrodes. However, due to the magnitude of the injected arc energy and the presence of the conductive gas, the arc persists without extinguishing, and there is a problem that it reaches the power supply member while losing a large amount of high-voltage electrodes. .

  The present invention does not use a fuse or a complicated and delayed interruption system on the side of the drive power supply control, and forms a space where the arc can be sustained (i.e., a time delay to extinguish the arc), and the arc is supplied to the power supply member. An object of the present invention is to provide a silent discharge plasma generating apparatus capable of completely extinguishing an arc before reaching a point and realizing a reliable recovery of interelectrode insulation, and a quenching method in the apparatus.

The present invention provides a dielectric, a first electrode provided opposite to the dielectric so as to provide a discharge space for generating gas by supplying gas, and the first electrode on the dielectric And a pair of electrodes composed of a second electrode composed of a conductive power supply thin film disposed opposite to each other with the dielectric interposed therebetween, an alternating current power source for applying and discharging an alternating voltage between the pair of electrodes, A power supply member that contacts the second electrode and connects the AC power source to the second electrode; and an arc extinguishing agent that is disposed so as to contact at least the second electrode of the dielectric and the second electrode. And when the dielectric is damaged and an arc discharge occurs between the electrodes, the arc discharge causes the second electrode to partially disappear from the portion where the arc discharge occurs to the portion where the power supply member contacts. At the same time, the arc Discharge in silent discharge type plasma generating apparatus characterized by extinguished.
The invention also includes a method of quenching in the device.

  According to the present invention, it is possible to provide a silent discharge type plasma generator capable of completely extinguishing the arc before it reaches the power supply member and realizing reliable recovery of the interelectrode insulation, and a quenching method in the device. .

It is sectional drawing of a set of electrode part of the cylindrical multi-tube type ozone generator which is a silent discharge type plasma generator by Embodiment 1 of this invention. It is a block diagram of the electric circuit of the ozone generator by this invention. It is a figure which shows the time change of the applied voltage at the time of the breakage occurrence concerning the ozone generator by this invention, and the flowing electric current. It is sectional drawing which shows the modification of the cylindrical multipipe type ozone generator by Embodiment 1 of this invention. It is sectional drawing which shows another modification of the cylindrical multi-tube type ozone generator by Embodiment 1 of this invention. It is sectional drawing of a set of electrode part in the modification of the cylindrical multipipe type ozone generator by Embodiment 1 of this invention. It is sectional drawing of a pair of electrode part of the cylindrical multi-tube type ozone generator by Embodiment 2 of this invention. It is sectional drawing of a set of electrode part by an example of the cylindrical multi-tube type ozone generator by Embodiment 4 of this invention. It is sectional drawing of a set of electrode part by another example of the cylindrical multi-tube type ozone generator by Embodiment 4 of this invention. It is sectional drawing of a set of electrode part of the cylindrical multi-tube type ozone generator by Embodiment 5 of this invention. It is sectional drawing of a set of electrode part by an example of the cylindrical multi-tube type ozone generator by Embodiment 6 of this invention. It is sectional drawing of a set of electrode part by another example of the cylindrical multi-tube type ozone generator by Embodiment 6 of this invention. It is sectional drawing of a set of electrode part of the cylindrical multi-tube type ozone generator by Embodiment 7 of this invention. It is sectional drawing of a pair of electrode part of the conventional cylindrical multi-tube type ozone generator. It is a figure for demonstrating generation | occurrence | production and arc extinction in a cylindrical multi-tube type ozone generator. It is a figure for demonstrating generation | occurrence | production and arc extinction in a cylindrical multi-tube type ozone generator.

  First, the present invention is capable of quickly and reliably interrupting an arc generated due to a short-circuit between electrodes, and extinguishing the arc quickly, even in a silent discharge plasma apparatus represented by an ozone generator having a large capacity (short-circuit current is large). To do. By utilizing the self-extinguishing effect of the thin-film high-voltage electrode disclosed in Patent Document 1 above, by installing an arc coolant at the arc generation site and the continuous path, the generated arc is cooled and the arc reaches the power supply member. The arc is extinguished before

For example, in a cylindrical multi-tube ozone generator using silent discharge with a glass tube as a dielectric as shown in Patent Document 1 above, when the glass tube is broken and an arc is generated,
1) The high voltage electrode formed on the inner surface of the glass tube is a thin film power supply film that is evaporated or sublimated by arc heat,
2) A power supply member that supplies current from the drive power source to the power supply film is in contact with the power supply film outside the discharge space.
3) It is realized by providing an arc extinguishing (cooling) agent in the arc continuous path between the power supply member and the damaged part.

  In the present invention, with the above structure, the arc generated between the electrodes is cooled by the arc extinguishing agent installed in the arc continuous path before reaching the power supply member. The cooled arc instantaneously increases its arc voltage, leading to extinction, i.e. restoring insulation between the electrodes, without stopping the entire ozone generation system (without removing the shorted electrode tube), It is possible to restart the ozone generator that has temporarily stopped discharging.

  In the present invention, an arc extinguishing agent is installed in a space surrounded by a glass tube and a thin film high voltage electrode disposed on the inner surface thereof. In the present invention, the arc sustaining path is limited to the space surrounded by the glass tube and the thin-film high-voltage electrode described above, and the arc always continues and progresses from the damaged portion of the glass tube toward the power supply member. That is, by arranging the arc extinguishing agent at least between the power supply member and the discharge space, the generated and sustained arc is always in contact with the arc extinguishing agent. The arc in contact with the arc extinguishing agent is rapidly cooled (increased arc electric field strength, increased arc voltage), and extinguishes.

  As shown in the above-mentioned Patent Document 1, if the power supply member is present in the discharge space, if the glass tube is damaged in the immediate vicinity, an arc is formed between the ground electrode and the power supply member via the damaged portion. Is generated, and a complete short circuit occurs instantaneously, so that it is disposed outside the discharge space.

  Further, in the structure of the present invention, since the high voltage electrode is a thin film, after the occurrence of breakage, the thin film high voltage electrode is self-disappearing due to the self-disappearance, and further due to the conductive gas generated in the glass tube. A time delay until the arc reaches the power supply member is provided. If the arc extinguishing agent is present closer to the point of occurrence of damage, the amount of unnecessary loss of the thin film high voltage electrode can be suppressed and the arc can be extinguished earlier, but the above-mentioned time delay is given. Therefore, from the viewpoint of avoiding a complete short circuit, if the arc extinguishing agent exists only between the power supply member and the discharge space, the amount of disappearance of the high voltage electrode may increase, but the arc is extinguished. The ozone generator does not reach a complete short circuit.

  The silent discharge plasma generator of the present invention is not limited to a so-called cylindrical multi-tube ozone generator, but can be applied to an apparatus using a parallel plate electrode structure. Further, the present invention can be similarly applied not only to an ozone generator but also to a carbon dioxide laser or a harmful gas decomposition apparatus using a similar discharge mode.

  In the present invention, a space that can sustain an arc (that is, a time delay to extinguish the arc) is formed without using a conventionally used fuse or a complicated and delaying system that generates a delay time on the side of the drive power supply control. By installing the arc extinguishing agent, the arc is completely extinguished before the arc reaches the power supply member, so that reliable interelectrode insulation recovery can be realized. Therefore, even when the short-circuit current is large, the self-extinguishing effect of the thin-film high-voltage electrode can be used effectively, and normal ozone generation can be performed again in areas other than the damaged part without stopping the ozone generation system. Can be realized. In addition, it is not necessary to use a fuse that has been an obstacle to downsizing of the ozone generator, and a significant downsizing can be realized.

  Hereinafter, a silent discharge type plasma generator according to the present invention will be described with reference to the drawings according to each embodiment, taking an ozone generator as an example.

Embodiment 1 FIG.
1 is a sectional view of a set of electrode portions of a cylindrical multi-tube ozone generator according to Embodiment 1 of the present invention. In FIG. 1, it has the ground electrode 1 (1st electrode) and the thin film high voltage electrode 2 (2nd electrode) which are the electric power supply thin films arrange | positioned facing predetermined gap length d. In addition, at least one dielectric 3 is disposed between the ground electrode 1 and the thin film high voltage electrode 2, and the ground electrode 1 and the dielectric 3 are concentric coaxial cylindrical tubes. The thin film high voltage electrode 2 is formed in close contact with the inner surface of the dielectric 3. The gap length d is called the discharge gap length, and the space formed by the discharge gap length is called the discharge space 4. The discharge gap length is set to 0.6 mm or less (hereinafter, the present invention will be described using this structure).

  In the discharge space 4, a gas containing oxygen is introduced as a source gas, and the ground electrode 1 and the thin-film high-voltage electrode 2 are connected via a metal power supply member 7 connected to a drive power source 6 that is an AC power source. Silent discharge plasma is generated by applying an alternating high voltage between the two. The power supply member 7 is in contact with the thin film high voltage electrode 2 outside the ground electrode 1, that is, outside the discharge space 4.

  In the plasma generated in the discharge space 4, oxygen molecules in the source gas collide with electrons to dissociate oxygen molecules, and ozone is generated by three-body collision. In FIG. 1, the arrow indicates the direction of gas flow, and ozone generated from the right end of the electrode part on the right side of the drawing is taken out. The ground electrode 1 is a stainless steel tube having both ends fixed to the tube plates 8 and 9, and the plurality of ground electrodes 1 are fixed to each other adjacent ground electrode with a predetermined interval. Furthermore, the tube sheets 8 and 9 are fixed to the container of the ozone generator. A space formed by the tube plates 8 and 9 and the inner wall of the container of the ozone generator (that is, a plurality of cylindrical ground electrodes 1 each housing the dielectric 3 portion) serves as the cooling water passage 5. Further, a glass tube is used for the dielectric 3. The glass tubes used for the dielectric 3 are the product names “DURAN (registered trademark) (8330)”, “AR-Glas (registered trademark) (8350)”, “8250”, “8252” and “8253” sold by SCHOTT. A wall having a thickness of 0.5 mm or more and an outer diameter of 30 mmφ or less was used.

  Further, the end of the glass tube at the ozone outlet is sealed in order to prevent the source gas from passing through the glass tube and contributing to the generation of ozone. For sealing the end of the glass tube, the glass itself may be processed, or a stopper made of silicon rubber or EPDM rubber may be provided. For the thin film high voltage electrode 2, a metal thin film having a thickness of 100 μm or less formed on the inner surface of the glass tube was used. In addition, as the plasma is generated, power is supplied to the discharge space. In the case of ozone generation, approximately 90% of the injected power is released as heat. The ground electrode 1 is in contact with the cooling water passage 5, and the discharge space 4 is cooled by the cooling water flowing through this passage to remove heat.

  A characteristic of this embodiment is that an arc coolant 10 as an arc extinguishing agent is installed in a space surrounded by the dielectric 3 and the thin film high voltage electrode 2. In FIG. 1, the arc coolant 10 is installed from immediately after the power supply member 7 to the entire discharge portion (the entire length of the discharge space 4) and the end portion of the glass tube. This is because the arc's continuous path is limited to the above-mentioned space, so it is surely installed in the arc's continuous / development path. Area). The arc coolant 10 has an action of cooling the generated arc and can extinguish the arc itself. Here, a polymer having a gel-like CH group, for example, a silicone gel (gel-like silicone compound) is used. Since the arc coolant 10 is in the form of a gel, the linear expansion coefficient is extremely small, and thermal stress accompanying the temperature rise of the thin film high voltage electrode 2 during normal ozone generation hardly occurs. Thus, the glass tube is not mechanically damaged.

  A large capacity in which a plurality of electrode parts shown in FIG. 1 are arranged side by side in parallel and the ozone generation amount is several tens kg / h or more, that is, the short-circuit current generated when the glass tube is broken is several tens to several hundreds A A case for generating ozone is formed, and the arc coolant 10 is installed in a space formed by the dielectric 3 and the thin-film high-voltage electrode 2, that is, the arc sustaining / propagating path, and the temperature and voltage value of the ozone generator The operation conditions were changed, and the operation was performed under conditions where dielectric breakdown occurred in the glass tube. As a result, in all cases where dielectric breakdown occurred, due to the self-extinguishing effect of the thin film high voltage electrode 2 and the presence of the arc coolant 10, a complete short circuit did not occur simultaneously with the occurrence of dielectric breakdown.

  Further, the self-dissipation amount of the thin-film high-voltage electrode 2 is stopped at substantially the same level as the self-dissipation amount shown in the above-mentioned Patent Document 1, and even in an ozone generator having a very short-circuit current, The arc was reliably extinguished in the vicinity, and the power supply member 7 was not reached. Therefore, after the arc is extinguished, it is possible to restart the system without stopping the ozone generation system and without replacing the glass tube. It was confirmed that it continued. In addition, as shown also in the said patent document 1, in the case of the thick film to which the high voltage electrode was firmly adhered, even if an arc coolant is installed, the thick film high voltage electrode that does not self-disappear with the ground electrode An arc was generated between them, causing a complete short circuit in an instant, and it was impossible to restart the ozone generator.

  The drive power source 6 in this embodiment that generates large-capacity ozone controls the current flowing into the ozone generator that is a capacitive load, and is driven even if a short circuit occurs between the electrodes of the ozone generator. The power source 6 tries to keep current flowing through the load. FIG. 2 shows a configuration diagram of an electric circuit of the ozone generator according to this embodiment, and FIG. 3 shows changes over time in applied voltage and flowing current when the ozone generator is damaged.

  When a certain electrode portion indicated by a broken electrode portion 19 in FIG. 2 is broken, the current I flowing through the circuit is substantially determined by the reactor 18 (inductive load component) left on the electric circuit. On the other hand, the voltage applied to the ozone generator suddenly drops at the moment of occurrence of damage (time t = t0). In this case, most of the current I flowing through the circuit flows to the broken electrode portion 19 having a low impedance and hardly flows to the unbroken electrode portion 20 having a high impedance. Further, in the damaged electrode portion 19, there is a voltage drop ΔV due to the electric resistance of the thin film high voltage electrode 2 from the power supply member 7 to the damaged position. Since vanishing begins (electrical resistance decreases), ΔV decreases with arc duration.

  When the arc coolant 10 shown in this embodiment is not installed, the voltage finally decreases to Varc (time t = t1) as shown by the broken line of the output voltage in FIG. 3, and the generated arc is fed. The member 7 is reached and a complete short circuit occurs. Time t = t2 indicates the time when the power supply is abnormally stopped due to a complete short circuit. This Varc is a so-called arc voltage, which is about a few tens to a hundred volts, although there are differences depending on the electrode material. On the other hand, during the self-disappearance period (Δt = t1−t0) of the thin film high voltage electrode 2, a voltage of Varc + ΔV obtained by adding the voltage drop ΔV of the thin film high voltage electrode 2 to the arc voltage Varc is applied. In other words, the voltage drops from the normal voltage value to Varc + ΔV immediately after the occurrence of the damage. The arc energy Warc input to the thin film high voltage electrode 2 is expressed as shown in Equation (1).

  Warc = ∫ ((Varc + ΔV) × I) dt (1)

  The arc coolant 10 shown in this embodiment absorbs the arc energy Warc and cuts off the current I. When an arc having a large current is generated and the arc acts on the arc coolant 10, the arc coolant 10 dissociates its chemical bond and generates and releases hydrogen gas having excellent thermal conductivity. Due to the release of hydrogen gas excellent in thermal conductivity and the pressure increase in the arc generation space accompanying the release, the generated arc is rapidly cooled and the arc diameter is reduced. As a result, the electric field strength of the arc increases, and Varc can be increased, leading to arc extinction (interruption of current I). Since the arc extinction needs to be completed before the arc reaches the power supply member 7, the arc needs to act on the arc coolant 10 at a timing from time t = t0 to t = t1. .

  In FIG. 3, the change in voltage and current when the arc coolant 10 is installed is indicated by a solid line, and the arc is extinguished at time t = t0 ′ without reaching time t = t1, and restarted. Has been. Even if the arc coolant 10 is installed, if the high voltage electrode is not a thin film but a thick film that is firmly adhered to the dielectric, there is no time Δt, and the arc is instantaneously generated at the timing of time t = t0. Unless the arc is extinguished, the possibility of a complete short circuit is extremely high. That is, the arc extinguishing agent 10 works effectively in this embodiment because of the unique self-disappearance period generated by the self-disappearance of the thin-film high-voltage electrode 2.

  A small amount of hydrogen is generated during arc extinguishing and does not affect ozone generation. In addition, the damaged part is in the form of a pinhole having a diameter of about 1 mm, and the raw material gas introduced into the ozone generator passes through the inside of the glass tube (3), not the discharge space 4, and is short-passed from the pinhole to the discharge space 4. The amount to be done is very small. In addition, since a large amount of source gas flows in the outer peripheral portion of the glass tube so that the amount of generated hydrogen can be ignored, hydrogen acting on the arc cooling flows out to the outside and does not cause a problem. Furthermore, even when the fracture form is accompanied by cracks or cracks that have further advanced from the pinhole shape, the gel-like arc coolant 10 is in close contact with the inner surface of the glass tube over the entire discharge space, so that the glass is separated. Therefore, the short path of the raw material gas is extremely small, and there is no element that causes an extreme decrease in the ozone generation efficiency in addition to a slight decrease in the ozone generation efficiency due to the stop of the ozone generation at the damaged portion.

  In FIG. 1, since the dielectric 3 sealed on the ozone outlet side on the right side of the drawing is used, it is not necessary to consider at all. However, when the ozone outlet side of the dielectric 3 is an open end, the installed arc coolant 10 Ozone may come into contact with both ends of the glass. The end corresponding to the ozone outlet is naturally exposed to the high-concentration ozone generated, and the raw material gas inlet side may be in contact with ozone diffused to the raw material gas inlet when the ozone generation system is stopped. is there. When a polymer is used as the arc coolant 10, the surface layer may deteriorate due to contact with ozone at a high concentration for a long time.

However, for example, even when the arc coolant 10 is in contact with high-concentration ozone of about 200 g / _N m ³ for 1000 hours, only a few millimeters of the surface layer is corroded and hardened, and the traveling speed is extremely small. Therefore, the source gas does not pass through the dielectric 3 without contributing to the generation of ozone, not in the discharge space. That is, since the arc coolant 10 can also serve as an end seal of the dielectric 3, it is not necessary to dare to process the end of the dielectric 3. Further, generally, the end portion on the ozone outlet side of the thin film high voltage electrode 2 exists inside the end portion of the ground electrode 1. In this configuration, creeping discharge (abnormal discharge) occurs from the end of the thin-film high-voltage electrode 2 on the ozone outlet side. Therefore, by applying an insulating or semiconductive material to the end, the occurrence of creeping discharge is prevented. Suppressed. In this embodiment, since the arc coolant 10 exists at the position of the end portion as indicated by reference numeral 10a in FIG. 1, the arc coolant 10 itself contributes to suppression of creeping discharge. Alternatively, it is not necessary to apply a semiconductive material.

  In addition, gel formation and gel placement inside the thin-film high-voltage electrode 2 are easy to fill the dielectric 3 in the atmosphere and fire and mold, but in this case, inside the arc coolant 10 after molding. Air bubbles may occur in When the arc coolant 10 comes into contact with ozone and the deterioration reaches the bubble portion, the bubble portion naturally becomes a space in which no arc coolant exists, and therefore the deterioration further progresses to the inside. Therefore, the arc coolant 10 is preferably formed in a state free of bubbles by defoaming treatment. Furthermore, since the gel is excellent in elasticity, it may be formed into a shape that can be installed in the dielectric 3 outside the ozone generator, and inserted and installed in the dielectric 3 after molding.

  In FIG. 1, the arc coolant 10 is installed almost throughout the dielectric 3. However, as shown in FIG. 4, a glass rod is inserted as the spacer 11, and the spacer 11, the dielectric 3, and the thin film high voltage electrode are inserted. (2) A space surrounded by the inner surface may be filled with silicone gel, and the arc coolant 10 may be molded. In addition, the spacer 11 has a relatively high heat resistance such as ceramics and fluororesin in addition to glass, and by using a rod or pipe made of a lightweight insulator, it is not necessary to remove the spacer 11 after gel molding. It can be incorporated into an ozone generator as it is and discharged.

  Similarly, the arc coolant 10 installed in the space surrounded by the inner surface of the thin film high voltage electrode 2 as shown in FIG. 5 may have a hollow structure. In these cases, the amount of self-dissipation of the thin-film high-voltage electrode 2 differs depending on the thickness of the arc coolant 10, but by setting the thickness to 100 μm or more, the arc can be generated even if breakage occurs in any part of the dielectric 3. The arc can be extinguished instantaneously after the arc is generated without reaching the power supply member 7. However, in the case of FIG. 5, since the arc coolant 10 has a hollow structure, it is impossible to seal the gas flowing inside the glass tube by the arc coolant 10, so one end of the dielectric 3 is closed. Need to be done.

  In the above description, the case where the high voltage electrode is a thin film has been described. However, the same effect can be obtained even when the ground electrode is also formed of a thin film as shown in FIG. In FIG. 6, a dielectric 1b made of, for example, a glass tube is formed on (inner side) the metal tube 1a fixed to the tube plates 8 and 9, and a thin film ground electrode 1c is further formed (inner side) thereon. Other structures are the same as those described above. Since no voltage is applied to the ground-side dielectric 1b, damage due to dielectric breakdown or the like occurs only in the high-voltage side dielectric. In the structure of FIG. 6, since not only the high voltage side electrode but also the ground side electrode is a thin film, the self-extinguishing effect of both electrodes can be used, and the arc duration is reduced. Furthermore, by adding the effect of the arc coolant 10, the arc can be completely extinguished instantaneously. It should be noted that the use of a thin-film ground electrode as the ground electrode can be applied as appropriate in the following embodiments, and has the same effect.

  As described above, since the arc coolant is disposed in the space formed by the dielectric and the thin-film high-voltage electrode, that is, the arc sustaining / propagating path, as shown in the first embodiment, the ozone generator has an extremely short circuit current. Even when it is large, the self-extinguishing effect of the thin-film high-voltage electrode can be used effectively, there is no fusing failure (short circuit protection failure) that occurs in the fuse, and the persistence of the arc generated by the short circuit is suppressed. Can be extinguished quickly. Therefore, no matter how much the dielectric material is damaged, no matter how large the short-circuit current occurs, the arc will continue and will not reach the power supply member. Without using the ozone generator, it is possible to prevent a complete short circuit of the ozone generator, and to greatly contribute to the downsizing and cost reduction of the ozone generator.

  Furthermore, it is not necessary to stop the entire ozone generation system, and the ozone generator can be restarted promptly. In addition, when the arc coolant is installed in almost the entire area inside the dielectric, the arc coolant also has a gas sealing effect to suppress the source gas from passing through the inside of the dielectric, and it is also necessary to seal the end of the dielectric. Absent. Furthermore, when the arc coolant has a hollow structure, the amount of arc coolant used can be reduced, which can contribute to cost reduction of the arc coolant. Furthermore, when the arc coolant is present at the end of the thin film high-voltage electrode at the ozone outlet side, creeping discharge generated from the end can also be suppressed.

Embodiment 2. FIG.
The gist of the present invention is not to prevent the arc from being generated, but to extinguish the generated / sustained arc before reaching the power supply member, thereby preventing a complete short circuit of the ozone generator. Due to the self-disappearance effect of the thin-film high-voltage electrode according to the invention of the above-mentioned Patent Document 1, the ozone generator does not instantaneously short-circuit instantly, but generates time for the thin-film high-voltage electrode to self-disappear in a non-complete short-circuit state. . This self-disappearance time is the time from the occurrence of an arc to a complete short-circuit, in other words, it can be said to be a time delay given to extinguish the arc. Further, as described above, the arc space is limited to a space surrounded by the dielectric and the thin film high voltage electrode.

  FIG. 7 shows a sectional view of a set of electrode portions of a cylindrical multi-tube ozone generator according to Embodiment 2 of the present invention. The same or corresponding parts as those in the above embodiment are denoted by the same reference numerals. In the electrode portion of FIG. 7, the arc coolant 10 is installed only between the power supply member 7 and the ground electrode 1 reflecting the above. That is, the arc coolant 10 is provided only on the outer side of the ground electrode 1, that is, the discharge space 4, adjacent to the power supply member 7. As the arc coolant 10, silicone gel was used as in the first embodiment. The installation amount (installation length) of the arc coolant 10 is related to the disappearance amount of the thin-film high-voltage electrode 2 at the time of arc occurrence. The larger the installation amount or the wider the installation range, the faster the arc can be cooled from the arc generation. From the viewpoint of preventing only complete short-circuiting, as shown in FIG. 7, since the generated arc finally reaches the power supply member 7, it may be installed only immediately after the power supply member 7.

  The arc coolant 10 is not limited to being installed in all the space cross sections where the arc continues, but may have a hollow structure as shown in the first embodiment. Furthermore, the silicone gel is not filled into the dielectric 3 and then fired and molded, but is fired and molded outside the dielectric 3 (that is, outside the ozone generator) and then inserted into the dielectric 3. May be installed. In this case, by covering the silicone gel with a polyamide resin film or the like, it is possible to reduce the frictional resistance at the time of insertion, and it can be easily inserted into the dielectric 3 (the effectiveness of the polyamide resin will be described in Embodiment 4 described later). Describe). Further, in this configuration, since the area where the thin film high voltage electrode 2 is in contact with high concentration ozone becomes extremely large, from the viewpoint of life, the end of the dielectric 3 on the ozone outlet side is subjected to end sealing, silicon rubber, EPDM. It is better to gas seal with a rubber stopper. Furthermore, unlike Embodiment 1, since there is no arc coolant at the ozone outlet side end of the thin film high voltage electrode 2, an insulating or semiconductive material is applied to the end (not shown), It is preferable to suppress creeping discharge generated from the end.

  Using the arc coolant 10 installed as described above, as shown in the first embodiment, the ozone generator is operated under the condition that the dielectric breakdown is generated in the dielectric glass tube. As a result, the most part of the thin-film high-voltage electrode 2 from the dielectric breakdown occurrence point, that is, from the arc occurrence point to the arc coolant 10 is self-disappearing, but the arc that has continued to reach the arc coolant 10 Is extinguished at the point of contact with the arc coolant 10, never reaches the power supply member 7, and the ozone generator does not fall into a complete short circuit. However, depending on the self-disappearance state of the thin-film high-voltage electrode 2 and the conduction state of the thin-film high-voltage electrode 2 reaching the arc generation site as viewed from the power supply member 7, ozone using the arc coolant 10 in this embodiment is used. In the generator, the glass tube in which the short circuit between the electrodes has occurred may not be able to continue the generation of ozone even after the arc is extinguished. However, all the glass tubes other than the glass tube in which the short circuit between the electrodes has occurred can contribute to ozone generation again without stopping the ozone generator system.

  Although the amount of disappearance of the thin film high voltage electrode is increased by this embodiment, the ozone generator can be prevented from being completely short-circuited as in the first embodiment. The arc can be completely extinguished just before the power supply member by effectively utilizing the time delay to complete short circuit due to the self-extinguishing effect of the thin film high voltage electrode. Therefore, the combination of the thin-film high-voltage electrode and the arc coolant prevents the arc from continuing to reach the power supply member when any short-circuit current occurs. It is possible to prevent the generator from being completely short-circuited, and it is not necessary to stop the entire ozone generation system in order to restart the ozone generator. In addition, by not using a fuse, it is possible to contribute to downsizing and cost reduction of the ozone generator. Furthermore, the cost of the arc coolant can be reduced by limiting the installation location and installation amount of the arc coolant.

Embodiment 3 FIG.
In the first and second embodiments, the case where the arc arc extinguishing agent to be installed is a silicone gel has been described. However, the arc arc extinguishing agent is not limited to a silicone polymer (for example, silicone gel), but a metal such as magnesium hydroxide or aluminum hydroxide. It is good also as the particle | grains or powdery solid containing any of hydroxide, silica sand, boric acid, or these mixtures, and the gelatinized thing. In this case, the same effects as those of the first and second embodiments can be obtained, and the arc cooling / extinguishing action can be effectively extracted from the above-described substances. The arc can be extinguished by installing it in a space where the arc surrounded by the body and the thin-film high-voltage electrode continues.

  As described above, by using the arc extinguishing agent shown in this embodiment, the self-extinguishing effect of the thin-film high-voltage electrode can be obtained even when the short-circuit current of the ozone generator is extremely large as in the first and second embodiments. Can be used effectively, and the duration of the arc generated due to the short circuit can be suppressed and the arc can be extinguished quickly. Therefore, even when a short-circuit current of any magnitude occurs, the arc persists and does not reach the power supply member, so it is possible to prevent a complete short circuit of the ozone generator without using a short-circuit prevention means such as a fuse, This can greatly contribute to the downsizing and cost reduction of the ozone generator. Furthermore, it is not necessary to stop the entire ozone generation system, and the ozone generator can be restarted promptly.

Embodiment 4 FIG.
In addition to the reaction gas and arc extinguishing action from the arc extinguishing agent as shown in the above-described first to third embodiments, the cooling of the arc includes the ablation cooling of the electrode component member (the surroundings during evaporation / sublimation) It is also very effective to use hydrogen generation. In other words, energy is taken away from the arc by latent heat generated when the component material of the electrode part evaporates, sublimates, or dissociates due to heat input from the arc generated between the electrodes, or by hydrogen generation similar to the arc coolant. Cooling), the arc can be extinguished.

8 and 9 are sectional views of a pair of electrode portions of a cylindrical multi-tube ozone generator according to Embodiment 4 of the present invention. The same or corresponding parts as those in the above embodiment are denoted by the same reference numerals. In FIG. 8, an ablation electrode 12 using copper is provided as a thin film high voltage electrode. Copper has an evaporation temperature of 1360 K and an evaporation energy of 4.8 × 10 ⁶ J / kg for arcs that are as high as hundreds or thousands of degrees, and flows into the arc's continuous path above the evaporation temperature. The ablation cooling effect can contribute to the cooling of the arc.

In FIG. 9, the thin film high voltage electrode 2 is covered with a coating layer 13 such as a fluororesin (PTFE), a polyamide resin, or a vinyl chloride resin. For example, in the case of PTFE, in addition to the evaporation temperature 600K and the evaporation energy 5.7 × 10 ⁴ J / kg, the dissociation temperature 3400K and the dissociation energy 1.2 × 10 ⁷ J / kg. Energy can be taken away and the arc can be extinguished. For example, the polyamide resin can also generate hydrogen by acting on the arc, and can further contribute to the arc cooling effect (from this point of view, it is very effective to cover the silicone gel shown in Embodiment 2 with the resin). .

  By the arc extinguishing action of the electrode member as described above, it is possible to extinguish the arc accompanying the short circuit generated in the ozone generator without reaching the power supply member. Further, by using the arc extinguishing agent shown in the first to third embodiments in combination, it is possible to realize further reliable complete short circuit prevention.

  By using the electrode component shown in this embodiment as described above, even when the short-circuit current of the ozone generator is extremely large, the self-disappearance effect of the thin-film high-voltage electrode can be effectively used. It is possible to suppress the arc that has occurred due to the short circuit and to extinguish the arc quickly. For this reason, no matter how large the short circuit current occurs, no matter how large the short circuit current occurs, the arc will continue and will not reach the power supply member. Without using it, it is possible to prevent a complete short circuit of the ozone generator and greatly contribute to the downsizing and cost reduction of the ozone generator. Furthermore, it is not necessary to stop the entire ozone generation system, and the ozone generator can be restarted promptly.

Embodiment 5 FIG.
FIG. 10 shows a cross-sectional view of a set of electrode portions of a cylindrical multi-tube ozone generator according to Embodiment 5 of the present invention. The same or corresponding parts as those in the above embodiment are denoted by the same reference numerals. In FIG. 10, the hydrogen storage alloy electrode 14 is used for the thin film high voltage electrode. It is extremely effective for cooling the arc. As the hydrogen storage alloy electrode 14, a hydride containing any one or more of magnesium, titanium, vanadium, and lanthanum is used. Hydrogen is occluded in the hydrogen storage alloy electrode 14, and when a short circuit occurs between the ground electrode 1 and the hydrogen storage alloy electrode 14 and an arc is generated, the arc heat is used to make the inside of the hydrogen storage alloy electrode 14 The hydrogen stored in can be easily released. The arc is cooled by utilizing the high thermal conductivity of the released hydrogen, and the insulation between the electrodes can be recovered without continuing until the arc reaches the power supply member 7.

  The thin film high voltage electrode 2 uses the metal thin film shown in the first to fourth embodiments, the ground electrode 1 is formed of the hydrogen storage alloy electrode 14, and the surface of the ground electrode 1 in contact with the discharge space 4 stores hydrogen. Even if the alloy (14) is formed, the same effect as described above can be obtained. By using these configurations in combination with the configurations shown in the first to fourth embodiments, it is possible to realize a more reliable complete short circuit prevention.

  By using the hydrogen storage alloy shown in this embodiment as described above for the thin film high voltage electrode, even when the short-circuit current of the ozone generator is extremely large, the self-extinguishing effect of the thin film high voltage electrode is effectively used. It is possible to suppress the persistence of the arc generated due to the short circuit and to extinguish the arc quickly. For this reason, no matter how large the short circuit current occurs, no matter how large the short circuit current occurs, the arc will continue and will not reach the power supply member. Without using it, it is possible to prevent a complete short circuit of the ozone generator and greatly contribute to the downsizing and cost reduction of the ozone generator. Furthermore, it is not necessary to stop the entire ozone generation system, and the ozone generator can be restarted promptly.

Embodiment 6 FIG.
Even when the arc extinguishing gas enclosed inside the dielectric and the thin film high voltage electrode is used for cooling the arc, the arc generated by the short-circuit between the electrodes does not reach the power supply member as in the first embodiment. Can be arced.

FIG. 11 shows a sectional view of a set of electrode portions of a cylindrical multi-tube ozone generator according to Embodiment 6 of the present invention. The same or corresponding parts as those in the above embodiment are denoted by the same reference numerals. In FIG. 11, arc extinguishing gas 15, which is an arc extinguishing agent, is sealed inside dielectric 3 and thin film high voltage electrode 2, and both ends of dielectric 3 are gas sealed. As the arc extinguishing gas, hydrogen, helium, sulfur hexafluoride, carbon dioxide, CF ₃ I (trifluoroiodomethane), and a gas obtained by mixing a plurality of these are effective. Conductivity and arc extinction can be used. The arc extinguishing gas 15 is more effective for arc extinction if it is sealed at a high pressure, preferably the operating pressure of the ozone generator. It was confirmed that it works well for arc extinguishing. The sealing pressure needs to be selected depending on the shape of the dielectric 3 to be used, particularly the thickness and the structure of the gas seal portion.

  In particular, in the case of being sealed at a high pressure, the arc extinguishing gas 15 acts on the arc extinction at the moment when the dielectric 3 is broken, and at the same time, flows out from the dielectric 3 to the discharge space 4, so that the thin film high voltage The conductive gas generated when the electrode 2 evaporates and sublimates passes through the discharge space and is discharged out of the ozone generator. Therefore, the gas in the arc sustaining / developing path does not increase the conductivity. Therefore, arc extinction can be completed with a very small amount of disappearance of the thin film high voltage electrode 2. In addition, when arc extinguishing occurs, these arc extinguishing gases 15 may be discharged together with ozonated oxygen as an output gas of the ozone generator, but because it is extremely small compared to ozonated oxygen, There is no major problem in the supply of ozonated oxygen. Furthermore, when the arc extinguishing method shown in the first to fifth embodiments is combined with this embodiment, it is possible to realize arc extinguishing at higher speed and more reliably.

  Further, as shown in FIG. 12, the arc extinguishing gas 15 is sealed in a container 16 and is placed in the dielectric 3 and the thin film high voltage electrode 2, particularly adjacent to the power supply member 7 and in the outer portion of the ground electrode 1, that is, the discharge space 4. Even if installed, the arc can be extinguished without reaching the power supply member 7. It is preferable that the container 16 is partially melted by heat input from an arc, such as a resin capsule. It is still more preferable to use the resin shown in Embodiment 4 as the container material. Further, arc-extinguishing gas may be enclosed in the molded silicone gel shown in the first embodiment and installed in the same manner as the container 16. In these cases, it is not necessary to perform gas sealing on the source gas side of the dielectric 3. Further, these configurations can be used in combination with the configurations shown in the first to fifth embodiments, thereby realizing a more reliable complete short circuit prevention.

  The arc-extinguishing gas shown in this embodiment as described above is enclosed in the space formed by the dielectric and the thin-film high-voltage electrode, that is, the arc sustaining / propagating path, so that the short-circuit current of the ozone generator is extremely low. Even when it is large, the self-extinguishing effect of the thin-film high-voltage electrode can be effectively used, and the persistence of the arc generated due to the short circuit can be suppressed and the arc can be extinguished quickly. For this reason, no matter how large the short circuit current occurs, no matter how large the short circuit current occurs, the arc will continue and will not reach the power supply member. Without using it, it is possible to prevent a complete short circuit of the ozone generator and greatly contribute to the downsizing and cost reduction of the ozone generator. Furthermore, it is not necessary to stop the entire ozone generation system, and the ozone generator can be restarted promptly.

Embodiment 7 FIG.
In the present invention, the conductive gas generated with the disappearance of the thin film high voltage electrode is responsible for the formation of a continuous path of the arc, and means for extinguishing the arc before reaching the power supply member is described in the first to the first embodiments. This is shown in FIG. In this embodiment, the conductive gas itself is removed from the arc sustaining space and is extinguished immediately after the arc is generated.

  FIG. 13 shows a sectional view of a set of electrode portions of a cylindrical multi-tube ozone generator according to Embodiment 7 of the present invention. The same or corresponding parts as those in the above embodiment are denoted by the same reference numerals. In FIG. 13, an adsorbent 17 for conductive gas generated with the occurrence of an arc is installed inside the dielectric 3 and the thin film high voltage electrode 2. As the adsorbent, it is effective to use zeolite, molecular sieves, carbon and the like.

  As the arc is generated, the adsorbent 17 adsorbs and absorbs the conductive gas particles of the thin-film high-voltage electrode 2 scattered in the space, thereby suppressing the arc duration without increasing the conductivity of the arc duration space. be able to. Therefore, the arc cannot be propagated continuously through the space, the arc is extinguished when the thin film high-voltage electrode 2 self-disappears according to the required insulation distance, and the power supply member 7 is not reached, There is no complete short circuit of the ozone generator. In addition, a metal ion neutralizer is installed in place of the adsorbent to neutralize and remove ionic species that maintain the conductivity of the persistent space, and use a ceramic base material that is used for commercial deodorizing applications. The same effect can be obtained by using a granular or honeycomb catalyst. In addition, these structures can be used in combination with the arc extinguishing method shown in the first to sixth embodiments, thereby realizing further reliable complete short circuit prevention.

  The conductive gas removing agent (adsorbent, metal ion neutralizing agent, deodorizing particulate, generic name for honeycomb catalyst) shown in this embodiment as described above is a space formed by a dielectric and a thin film high voltage electrode, In other words, even when the short circuit current of the ozone generator is extremely large due to the installation in the arc sustaining / propagating path, the conductive gas generated by the self-dissipation of the thin film high voltage electrode is adsorbed or decomposed. The duration of the generated arc can be suppressed and the arc can be quickly extinguished. For this reason, no matter how large the short circuit current occurs, no matter how large the short circuit current occurs, the arc will continue and will not reach the power supply member. Without using it, it is possible to prevent a complete short circuit of the ozone generator and greatly contribute to the downsizing and cost reduction of the ozone generator. Furthermore, it is not necessary to stop the entire ozone generation system, and the ozone generator can be restarted promptly.

  The present invention is not limited to the above embodiments, and it goes without saying that all possible combinations of these embodiments are included as described above.

  1 ground electrode, 1a metal tube, 1b dielectric, 1c thin film ground electrode, 2 thin film high voltage electrode, 3 dielectric (glass tube), 4 discharge space, 5 cooling water passage, 6 drive power supply (AC power supply), 7 power supply Member, 8, 9 Tube plate, 10 Arc coolant (arc extinguishing agent), 11 Spacer, 12 Ablation electrode, 13 Coating layer, 14 Hydrogen storage alloy electrode, 15 Arc extinguishing gas, 16 Container, 17 Adsorbent, 18 Reactor, 19 Damaged electrode part, 20 Undamaged electrode part, 21 Damaged part.

Claims (8)

A dielectric,
A first electrode provided opposite to the dielectric so as to provide a discharge space for generating a plasma by supplying gas, and opposed to the first electrode on the dielectric with the dielectric interposed therebetween A set of electrodes comprising a second electrode comprising an electrically conductive power supply thin film disposed;
An alternating current power source for applying and discharging an alternating voltage between the set of electrodes;
A power supply member that contacts the second electrode and connects the AC power source to the second electrode;
An arc extinguishing agent disposed to contact at least a second electrode of the dielectric and the second electrode;
With
When the dielectric is damaged and an arc discharge occurs between the electrodes, the arc discharge causes the second electrode to partially disappear from the portion where the arc discharge occurs to the portion where the power supply member contacts, A silent discharge type plasma generator, wherein arc discharge is extinguished by the arc extinguishing agent.   2. The silent discharge plasma generator according to claim 1, wherein the arc extinguishing agent is formed of a silicone compound.   2. The silent discharge plasma generator according to claim 1, wherein the arc extinguishing agent contains at least one material selected from the group consisting of aluminum hydroxide, magnesium hydroxide, silica sand, and boric acid.   The silent discharge type according to claim 1, wherein the arc extinguishing agent includes at least one gas selected from the group of gas materials of hydrogen, helium, sulfur hexafluoride, carbon dioxide, and trifluoroiodomethane. Plasma generator.   A coating layer made of any one of a fluororesin, a polyamide resin, and a vinyl chloride resin is provided along at least one of the second electrode and the arc extinguishing agent. The silent discharge type plasma generator according to the item.   The AC power supply is connected to the second electrode outside the discharge space via the power supply member, and the power supply member and the power supply member side of the first electrode disposed to face the second electrode The silent discharge type plasma generator according to any one of claims 1 to 5, wherein the arc extinguishing agent is installed between the ends of the silent discharge plasma generator.   A dielectric,
  A first electrode provided opposite to the dielectric so as to provide a discharge space for generating a plasma by supplying gas, and opposed to the first electrode on the dielectric with the dielectric interposed therebetween A set of electrodes comprising a second electrode comprising an electrically conductive power supply thin film disposed;
  An alternating current power source for applying and discharging an alternating voltage between the set of electrodes;
  A power supply member that contacts the second electrode and connects the AC power source to the second electrode;
  A conductive gas removing agent that is disposed in a space formed by the dielectric and the second electrode and removes a conductive gas generated due to the disappearance of the second electrode;
  With
  When the dielectric is damaged and an arc discharge occurs between the electrodes, the arc discharge causes the second electrode to partially disappear from the portion where the arc discharge occurs to the portion where the power supply member contacts, A silent discharge type plasma generator characterized in that the conductive gas generated due to the extinction of the second electrode is removed by the conductive gas removing agent to eliminate arc discharge.   1 comprising a first electrode provided to face a dielectric so as to provide a discharge space, and a second electrode disposed on the dielectric so as to face the first electrode and the dielectric. A method of quenching in a silent discharge plasma generator that includes a set of electrodes and an AC power source that discharges by applying an AC voltage between the electrodes, and supplies gas to the discharge space to form plasma,
  When the second electrode is formed of a conductive thin film and the dielectric is damaged and an arc discharge occurs between the electrodes, the second electrode is removed from the portion where the arc discharge is generated by arc discharge. A part of the power supply member that is in contact with the second electrode and in contact with the second electrode is contacted with the second electrode,
  At the same time, an arc extinguishing agent is disposed so as to contact at least the second electrode of the dielectric and the second electrode to extinguish the arc discharge.
  A method for extinguishing a silent discharge plasma generator characterized by the above.

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