JP2004247223A - Electrode for gas excitation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode for gas excitation capable of extending its service life, and of reducing its cost. <P>SOLUTION: This electrode 40 for gas excitation includes: a cylindrical core electrode 41; and a cylindrical insulation sheath 42 surrounding the core electrode 41. The cross-sectional area of the sheath 42 is not less than 70% of the area of the cross-sectional circle of the electrode 40. A code 43 is a void part and filled with air. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００３２】
【充填物の評価例】
（１）アルミニウム製芯電極（直径＝１．５ｍｍ）とその芯電極を包囲するガラス製円筒状保護鞘体（外径＝４ｍｍ；ガラス厚さ＝１．２ｍｍ）とから電極を製造した。前記電極の断面積に占める芯電極の面積は１４％であり、円筒状保護鞘体の面積は８４％であり、空隙部の占める面積は２％であった。なお、前記空隙部には、空気又はフッ素系不活性液体（フロリナート；３Ｍ社，米国）を充填した。
また、アルミニウム製芯電極（直径＝２ｍｍ）とその芯電極を包囲するガラス製円筒状保護鞘体（外径＝４ｍｍ；ガラス厚さ＝０．８ｍｍ）とから電極を製造した。前記電極の断面積に占める芯電極の面積は２５％であり、円筒状保護鞘体の面積は６４％であり、空隙部の占める面積は１１％であった。なお、前記空隙部には、空気又はフッ素系不活性液体（フロリナート；３Ｍ社，米国）を充填した。
これらの各電極について、図８に示す方法で、試験電圧１８ｋＶ（一定）又は１８．５ｋＶ（一定）を印加し、電極破壊試験を実施した。
【００３３】
（２）結果を以下の表２に示す。
【表２】

試験の結果、高電圧側電極の保護鞘体のガラス面積比が８４％である電極は、６４％の電極よりもはるかに寿命が長いことがわかった。
【００３４】
【発明の効果】
本発明によれば、気体励起用電極の寿命を延長させ、コスト低減を達成することができる。特には、比較的廉価なガラス製鞘体を有する電極の寿命を延長させることができる。
【図面の簡単な説明】
【図１】本発明の電極が使用可能な保護電極型気体励起装置のハウジングの側壁の一部を切り欠いて示す模式的斜視図である。
【図２】図１の保護電極型気体励起装置の模式的断面図である。
【図３】保護電極型気体励起装置の基本的構造を示す模式的断面図である。
【図４】本発明装置の基本的構造を示す模式的断面図である。
【図５】本発明の電極が使用可能な露出電極型気体励起装置のハウジングの側壁の一部を切り欠いて示す模式的斜視図である。
【図６】図５の露出電極気体励起装置の模式的断面図である。
【図７】本発明による気体励起用電極の構造を模式的に示す断面図である。
【図８】気体励起用電極の破壊試験の実施方法を模式的に示す斜視図である。
【符号の説明】
１・・・ハウジング；１Ａ，１Ｂ・・・支持壁；２・・・流入用開口部；
３・・・排出用開口部；４Ａ・・・保護電極；
４Ａ−１０，４Ａ−２０・・・保護電極列；
４ａ−１１，４ａ−１２・・・保護電極群；
４ａ−２１，４ａ−２２・・・保護電極群；
４Ｂ・・・露出電極；５・・・芯電極；６・・・円筒状鞘体；
７Ａ，７Ｂ・・・電線；８，４８・・・交流電源；１０・・・気体励起装置；
４０・・・気体励起用電極；４０Ａ・・・試験対象保護電極；
４１，４１Ａ・・・円柱状芯電極；４２，４２Ａ・・・円筒状絶縁体鞘体；
４３・・・空隙部；４５・・・端子；５０・・・気体励起装置；
５１・・・ハウジング；５２・・・流入用開口部；
５３・・・排出用開口部；５４（５４Ａ，５４Ｂ）・・・保護電極；
５５・・・芯電極；５６・・・円筒状鞘体；５７Ａ，５７Ｂ・・・電線；
５８・・・交流電源；６０・・・カッター；６１・・・カッターの刃；
６２・・・カッターの端部；
Ｇ・・・被処理気体；Ｃ・・・処理済み気体。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrode for gas excitation. According to the gas excitation electrode of the present invention, the service life can be extended.
[0002]
[Prior art]
Various devices are known as gas excitation devices that generate gas at low temperatures by inducing gas under AC high-pressure discharge conditions, for example, Japanese Patent Application Laid-Open No. 9-199261 (Patent Document 1). And US Pat. No. 5,483,117 (Patent Document 2) also describe a gas excitation device. A typical embodiment of such a conventionally known gas excitation device is shown in FIG. FIG. 1 is a schematic perspective view in which a part of the side wall of the housing 51 of the gas excitation device 50 is cut away. The gas excitation device 50 includes a substantially rectangular parallelepiped housing 51 having an inflow opening 52 for the gas to be processed G and an opening 53 for discharging the processed gas C. In the housing 51, A large number of protective electrodes 54 are provided. As shown in the schematic cross-sectional view of FIG. 2, the protective electrode 54 includes a core electrode 55 and a cylindrical sheath 56 that surrounds the periphery of the core electrode 55. Made of insulator material. Further, the protective electrode 54 is divided into two groups of electrode groups 54A and 54B, which are connected to electric wires 57A and 57B, respectively, and the electric wires 57A and 57B are connected to an AC power source 58. Further, the electric wire 57B connected to the electrode group 54B of one series is grounded. As shown in FIG. 2, each protective electrode 54 </ b> B that is disposed on the outermost side inside the housing 51 and faces the inner wall of the housing 51 is grounded so that no discharge occurs between the inner wall of the housing 51. It is preferable to connect to the electric wire 57B. In principle, it is not necessary to ground the housing 51 itself, but it is preferable to ground the housing 51 from the viewpoint of safety.
[0003]
Furthermore, a deodorizing device and an air purifying device using low temperature non-equilibrium plasma generated by the gas excitation device are known. For example, Japanese Patent Laid-Open No. 2001-293079 (Patent Document 3) discloses a low-temperature plasma deodorization apparatus having a high-pressure discharge section that generates low-temperature plasma and a catalyst section that is disposed downstream of the high-pressure discharge section and is filled with an oxidation promoting catalyst. Is described. In the high-pressure discharge section, radicals are generated by giving dissociation energy to the gas to be treated by high-pressure discharge. That is, the electrons released into the gas by the discharge strike the gas molecules in the odor gas and activate the molecules. Some of the active molecules are dissociated into radicals, which are considered to oxidize and decompose malodorous substances in the odor gas or generate ozone. The ozone generated by radicals is also considered to oxidize malodorous substances and contribute to the treatment of malodorous substances. Also, the odorous substance is oxidatively decomposed by the energy of the discharge itself.
[0004]
[Patent Document 1]
JP-A-9-199261 [Patent Document 2]
US Pat. No. 5,483,117 [Patent Document 3]
Japanese Patent Laid-Open No. 2001-293079
[Problems to be solved by the invention]
In the gas exciter of the type shown in FIG. 1, a relatively inexpensive glass tube has been widely used as an insulator sheath. However, in the conventional glass tube, when the continuous operation is continued for about four months, the breakage rate of the glass tube is rapidly increased. Therefore, electrode replacement work is required, and the running cost is expensive, and the gas excitation device has to be stopped each time.
Therefore, the subject of this invention is extending the lifetime of the electrode for gas excitation of the type shown in FIG. 1, and aiming at cost reduction. In particular, it is to extend the life of an electrode having a relatively inexpensive glass sheath.
[0006]
[Means for Solving the Problems]
According to the present invention, the subject is an electrode for gas excitation including a cylindrical core electrode and a cylindrical insulator sheath surrounding the cylindrical core electrode, and an area of a circle in a cross section of the electrode On the other hand, it can be solved by the electrode, wherein the cylindrical insulator sheath has a cross-sectional area of 70% or more.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The gas excitation electrode according to the present invention can be used by being attached to a gas excitation device. A general gas excitation device includes at least a pair of electrodes connected to an AC power source in a housing having an opening for inflow of a gas to be processed and an opening for discharge of a processed gas. The combination of the pair of electrodes is, for example,
(A) A combination of protective electrodes that includes a core electrode and an insulator sheath that surrounds the core electrode, and the outer surface of the insulator sheath is in contact with the gas to be treated (that is, between the protective electrodes) Or a combination of (B) (1) the protective electrode and (2) an exposed electrode that is in direct contact with the gas to be treated (that is, a combination of the protective electrode and the exposed electrode). In the combination (B), both the exposed electrode and the housing are grounded.
The electrode for gas excitation according to the present invention is used as a protective electrode in the gas excitation device.
[0008]
In the present specification, the device having the electrode of the combination (A) is hereinafter referred to as “protective electrode type device”, and the device having the electrode of the combination (B) is hereinafter referred to as “exposed electrode type device”. I will decide. The protective electrode type device is conventionally known, but the exposed electrode type device is not known conventionally (see Japanese Patent Application No. 2002-341158). The “protective electrode type device” is, for example, a gas described in Japanese Patent Application Laid-Open No. 9-199261 (Patent Document 1) and US Pat. No. 5,483,117 (Patent Document 2). It is the same device as the excitation device.
[0009]
First, typical aspects of the protective electrode type device will be described with reference to the accompanying drawings. FIG. 1 is a schematic perspective view in which a part of the side wall of the housing 51 of the protective electrode type device 50 is cut away. The protective electrode type device 50 includes an opening 52 for inflow of a contaminated gas (for example, atmosphere) G to be processed in a portion corresponding to the upper surface of a substantially rectangular parallelepiped housing 51, and processing is performed in a portion corresponding to the bottom surface of the housing 51. An opening 53 for discharging the finished gas (for example, the atmosphere) C is provided. In addition, a large number of protective electrodes 54 are provided in the housing 51 where high-pressure discharge treatment is performed. As shown in the schematic cross-sectional view of FIG. 2, the protective electrode 54 includes a cylindrical core electrode 55 and a cylindrical sheath 56 surrounding the core electrode 55. The plurality of protective electrodes 54 are arranged parallel to each other with a space therebetween and in a direction perpendicular to the flow direction of the contaminated gas to be treated, and both ends of each electrode are respectively supported by the support walls of the housing 51. It is supported by 51A and 51B.
[0010]
The plurality of protective electrodes 54 are divided into two systems, each of which is grouped and connected together to the electric wires 57A and 57B, and the electric wires 57A and 57B are connected to the AC power source 58. In addition, the electric wire 57B connected to the protective electrode 54B of one series is grounded. As shown in FIG. 2, each protective electrode 54 </ b> B that is disposed on the outermost side inside the housing 51 and faces the inner wall of the housing 51 is grounded so that no discharge occurs between the inner wall of the housing 51. It is preferable to connect to the electric wire 57B. In principle, it is not necessary to ground the housing 51 itself, but it is preferable to ground the housing 51 from the viewpoint of safety.
[0011]
When, for example, a gas to be processed (for example, the atmosphere) G flows from the inflow opening 52 of the protective electrode type device 50 and a high voltage is applied to the two electrode groups 54A and 54B by the AC power source 58, the two electrode systems A discharge occurs between the groups 54A and 54B, and gas molecules are excited to generate radicals. By these radicals, malodorous substances in the gas to be treated are oxidatively decomposed or ozone is generated, so that the gas to be treated is oxidized. Further, the gas to be treated is discharged from the discharge opening 53 together with the radicals and ozone thus generated, and sent to a catalyst part (not shown) filled with the oxidation promoting catalyst. The reaction can proceed further and the gas treatment can be continued. Further, when a high voltage is applied to the two electrode groups 54A and 54B by the AC power source 58, a discharge occurs between the two electrode groups 54A and 54B, and the surface of each electrode, that is, the cylindrical sheath 56 Suspended particles, particularly suspended particulate matter (SPM) in a gas to be treated (for example, the atmosphere) can be attached to the surface.
[0012]
In the protective electrode type device, the plurality of protective electrode groups are arranged so that discharges are generated almost uniformly in the housing and the gas to be processed passing between the electrodes is processed almost evenly. Yes. However, the plurality of protective electrode groups are arranged parallel to each other with a space therebetween and perpendicular to the flow direction of the gas to be processed, and one protective electrode of one electrode series 54A is connected to the other. It is preferable that the four protective electrodes of the electrode series 54B are surrounded, and conversely, one protective electrode of the other electrode series 54B is arranged in a state of being surrounded by the four protective electrodes of one electrode series 54A.
[0013]
Next, the exposed electrode type device will be described with reference to the accompanying drawings. The exposed electrode type device is an improved version of the conventional type device shown in FIGS. First, differences in the basic structure between the exposed electrode type device and the protective electrode type device will be described with reference to FIGS.
FIG. 3 is a schematic cross-sectional view showing the basic structure of the protective electrode type device shown in FIGS. As described above, the protective electrode type device 50 includes the housing 51 having the inflow opening 52 for the contaminated gas G to be processed and the opening 53 for discharging the processed gas C. , Protective electrodes 54A, 54B, 54B are provided. The protective electrodes 54 </ b> A, 54 </ b> B, 54 </ b> B each include a core electrode 55 and a sheath body 56 that surrounds the core electrode 55. The electrode 54A is connected to the electric wire 57A, the electrodes 54B and 54B are connected to the electric wire 57B, and the electric wires 57A and 57B are connected to the AC power source 58. Moreover, since the electrodes 54B and 54B are arrange | positioned on the outer side in the housing 51, and oppose the inner wall of the housing 51, the electric wire 57B connected to them is earth | grounded.
[0014]
On the other hand, FIG. 4 is a schematic cross-sectional view showing the basic structure of the exposed electrode type device. The exposed electrode type device 10 includes a housing 1 having an inflow opening 2 for a contaminated gas G to be treated and an opening 3 for discharging a treated gas C. Inside the housing 1, a protective electrode 4A is provided. And exposed electrodes 4B and 4B. As described above, the protective electrode type device 50 includes the protective electrodes 54A, 54B, and 54B, whereas the exposed electrode type device 10 includes the exposed electrodes 4B and 4B instead of the protective electrodes 54B and 54B. Is different. The protective electrode 4 </ b> A includes a core electrode 5 and a sheath body 6 that surrounds the core electrode 5, similarly to the protective electrode type device 50. The protective electrode 4A is connected to the electric wire 7A, the exposed electrodes 4B and 4B are connected to the electric wire 7B, and the electric wires 7A and 7B are connected to the AC power source 8. Moreover, the electric wire 7B connected to the exposed electrodes 4B and 4B is grounded. Further, in the exposed electrode type device 10, the housing 1 also needs to be grounded, which is also different from the protective electrode type device 50 in this respect. In the exposed electrode type device 10, since it is preferable to apply a high voltage to the protective electrode 4A side, it is not preferable to dispose the protective electrode 4A on the outermost side inside the housing 1. That is, as shown in FIG. 4, the exposed electrodes 4 </ b> B and 4 </ b> B are preferably arranged on the outermost side inside the housing 1 so as to face the inner wall of the housing 1.
[0015]
In the protective electrode type device shown in FIG. 3, discharge occurs between the core electrode 55 in the protective electrode 54A and the core electrodes 55 in the protective electrodes 54B on both sides. In this discharge, two layers of insulator layers of the two sheath bodies 56 are interposed between the pair of core electrodes 55 and 55. On the other hand, in the exposed electrode type device 10 shown in FIG. 4, discharge occurs between the core electrode 5 in the protective electrode 4A and the exposed electrodes 4B on both sides. In this discharge, only one insulator layer of one sheath body 6 is interposed between one core electrode 5 and the exposed electrode 4B, and the excitation capability is improved. The amount of ozone generated increases. In the exposed electrode type device 10 shown in FIG. 4, since the housing 1 and the exposed electrodes 4B and 4B are both grounded, no discharge occurs between the housing 1 and the exposed electrodes 4B and 4B.
[0016]
As shown in FIG. 4, in the exposed electrode type device 10, a combination of the protective electrode 4A and the exposed electrode 4B is used instead of the pair of protective electrodes 54A and 54B in the protective electrode type device 50 shown in FIGS. There are only differences. Therefore, a certain aspect of the exposed electrode type device will be described with reference to FIGS. That is, FIG. 5 is a schematic perspective view in which a part of the side wall of the housing 1 of the exposed electrode type apparatus 10 is cut away, and FIG. 6 is a schematic cross-sectional view thereof.
[0017]
As shown in FIGS. 5 and 6, the exposed electrode type device 10, like the protective electrode type device 50, is used for inflow of a gas to be processed (for example, atmospheric air) G into a portion corresponding to the upper surface of the substantially rectangular parallelepiped housing 1. An opening 2 is provided, and a portion corresponding to the bottom surface of the housing 1 is provided with an opening 3 for discharging treated gas (for example, the atmosphere) C. In addition, in the housing 1 where the high-pressure discharge treatment is performed, a plurality of cylindrical protective electrodes 4A and a plurality of cylindrical exposed electrodes 4B are parallel to each other with a space therebetween, and the contamination gas to be treated ( For example, both ends of each electrode are supported by support walls 1A and 1B of the housing 1, respectively.
[0018]
On the other hand, the cylindrical exposed electrode 4B has substantially the same dimensions as the cylindrical sheath 6 of the protective electrode 4, and the electrode surface is exposed, so that it directly contacts the gas to be treated (for example, the atmosphere). The plurality of protective electrodes 4 </ b> A and the plurality of exposed electrodes 4 </ b> B are grouped and connected together to the electric wires 7 </ b> A and 7 </ b> B, and the electric wires 7 </ b> A and 7 </ b> B are connected to the AC power supply 8. The exposed electrode 4B is disposed on the outermost side in the housing 1, and the electric wire 7B connected to the plurality of exposed electrodes 4B is grounded. Furthermore, the housing 1 is also grounded.
[0019]
When a contaminated gas (for example, the atmosphere) G is introduced from the inflow opening 2 of the exposed electrode type device 10 and a high voltage is applied to the two electrode groups 4A and 4B by the AC power supply 8, the two electrode groups. A discharge occurs between 4A and 4B, and gas molecules are excited to generate radicals. By these radicals, malodorous substances in the gas to be treated are oxidatively decomposed or ozone is generated, so that the gas to be treated is oxidized. Further, the gas to be treated is discharged from the discharge opening 3 together with the radicals and ozone thus generated, and sent to a catalyst part (not shown) filled with the oxidation promoting catalyst. The reaction can proceed further and the gas treatment can be continued. Further, when a high voltage is applied to the two electrode groups 4A and 4B by the AC power supply 8, a discharge occurs between the two electrode groups 4A and 4B, and the surface of the exposed electrode 4B and the surface of the protective electrode 4A, that is, Suspended particles in gas (for example, the atmosphere), in particular, suspended particulate matter (SPM) can be attached to the surface of the cylindrical sheath body 6.
[0020]
The exposed electrode used in the exposed electrode type device can be composed of any conductive material, and examples thereof include aluminum or an alloy thereof, copper, a carbonaceous material, iron or an alloy thereof, and tungsten. The exposed electrode is in direct contact with the gas to be treated (for example, contaminated atmosphere), and thus has corrosion resistance and is easy to perform maintenance such as cleaning operation and replacement operation, such as stainless steel (for example, SUS). ) Is preferably used.
Further, the shape of the exposed electrode is not particularly limited, but is manufactured by twisting a rod-shaped body (for example, a cylindrical body or a columnar body, particularly a cylindrical body or a columnar body), or a conductive wire. It can also be a stranded wire electrode.
[0021]
In the exposed electrode type apparatus, the plurality of exposed electrode groups and the plurality of protective electrode groups are arranged so that discharges are generated almost uniformly in the housing, and the contaminated atmosphere to be processed passing between the electrodes is substantially uniform. Are arranged to be processed. However, a plurality of exposed electrode groups and a plurality of protective electrode groups are arranged parallel to each other with a space therebetween, and in a direction perpendicular to the flow direction of the contaminated atmosphere to be treated. It is preferable that the protective electrode is disposed so as to be surrounded by the protective electrode, and that one protective electrode is surrounded by the four exposed electrodes.
[0022]
As described above, the gas excitation electrode according to the present invention can be used as a protective electrode in, for example, the protective electrode type or exposed electrode type gas excitation device.
The structure of the gas excitation electrode according to the present invention is schematically shown in FIG. 7 (cross-sectional view). That is, the gas excitation electrode 40 according to the present invention includes a columnar core electrode 41 and a cylindrical insulator sheath 42 surrounding the columnar core electrode 41. Further, a gap 43 may be included between the columnar core electrode 41 and the cylindrical insulator sheath 42.
[0023]
In the gas excitation electrode according to the present invention, the cross-sectional area occupied by the cylindrical insulator sheath is 70% or more with respect to the area of the circle of the cross section. When the cross-sectional area occupied by the cylindrical insulator sheath is less than 70%, the service life for long-term continuous use is shortened. The cross-sectional area occupied by the cylindrical insulator sheath is preferably 75% or more, and more preferably 80% or more.
[0024]
The cylindrical insulator sheath is not particularly limited as long as it is made of an insulator, but the outer surface of the cylindrical sheath is in direct contact with the gas to be treated (for example, contaminated atmosphere). Therefore, it is preferable to use a material having corrosion resistance and easy maintenance such as a cleaning operation and a replacement operation, for example, a synthetic resin (for example, polytetrafluoroethylene) or ceramics, and is made of glass, And it is more preferable from the viewpoint of cost. Although any glass can be used as the glass, for example, borosilicate glass is preferable in terms of heat resistance and strength.
[0025]
The cylindrical core electrode can be made of any conductive material, and examples thereof include aluminum or an alloy thereof, copper, a carbonaceous material, iron or an alloy thereof, and tungsten. In addition, since the said core electrode does not contact with a to-be-processed contaminated gas directly, it does not need to have corrosion resistance in particular. The shape of the core electrode is not particularly limited, but is manufactured by twisting a rod-shaped body (for example, a cylindrical body or a columnar body, particularly a cylindrical body or a columnar body), or a conductive wire. It can also be a stranded wire electrode.
[0026]
Since the core electrode generally expands at the time of discharge, it is preferable to provide a gap between the surface of the core electrode and the inner surface of the cylindrical sheath body so as to provide an interval of at least 0.05 mm. The void can be filled with air, a suitable inert gas (eg, nitrogen gas, argon gas), or an insulating liquid (eg, a fluorine-based inert liquid), or a reduced pressure or vacuum state. You can also. As will be described later, it is preferable to fill with air. In addition, the space between the surface of the core electrode and the inner surface of the cylindrical sheath is too wide. For example, when the thickness is 1.0 mm or more, discharge occurs between the surface of the core electrode and the inner surface of the cylindrical sheath. This is not preferable.
[0027]
In the gas excitation electrode according to the present invention, the size of the electrode is not particularly limited, but in an electrode that is generally widely used, the outer diameter of the electrode is about 3 mm to 10 mm. Further, the length of the electrode is not particularly limited, but in the case of a generally widely used electrode, the length is about 50 mm to 1000 mm.
[0028]
【Example】
EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but these do not limit the scope of the present invention.
[Electrode breakdown test]
In the electrode breakdown test, discharge was performed under conditions more severe than those of an actual gas excitation device, and durability was evaluated in a short time. Specifically, as shown in FIG. 8, a test object protection electrode 40A including a columnar core electrode 41A and a cylindrical insulator sheath 42A is placed on the blade 61 of the cutter 60 at a right angle, and the protection electrode A terminal 45 provided at one end of 40 </ b> A was connected to an AC power supply 48, and further connected to an end 62 of the cutter 60 from the AC power supply 48. The AC power supply 48 and the cutter 60 were grounded. Note that the gap between the cylindrical core electrode 41A and the cylindrical insulator sheath 42A is not shown.
[0029]
[Evaluation example of glass thickness]
(1) Ten electrodes were manufactured from an aluminum core electrode (diameter = 1.5 mm) and a glass cylindrical protective sheath (outer diameter = 4 mm; glass thickness = 1.2 mm) surrounding the core electrode. . The area of the core electrode in the cross-sectional area of the electrode was 14%, the area of the cylindrical protective sheath body was 84%, and the area occupied by the gap was 2%. The gap was filled with air. About these electrodes, the test voltage 18.1 kV (constant) was applied by the method shown in FIG. 8, the electrode destruction test was implemented, and the time until a glass-made cylindrical protective sheath body destroyed was measured.
[0030]
(2) Ten electrodes were manufactured from an aluminum core electrode (diameter = 2 mm) and a glass cylindrical protective sheath (outer diameter = 4 mm; glass thickness = 0.8 mm) surrounding the core electrode. The area of the core electrode in the cross-sectional area of the electrode was 25%, the area of the cylindrical protective sheath body was 64%, and the area occupied by the gap was 11%. The gap was filled with air. For these electrodes, as in the previous item (1), a test voltage of 18.1 kV (constant) was applied by the method shown in FIG. 8 to conduct an electrode destruction test, and the glass cylindrical protective sheath body was destroyed. The time until was measured.
[0031]
(3) The results are shown in Table 1 below.
[Table 1]

[0032]
[Evaluation example of packing]
(1) An electrode was manufactured from an aluminum core electrode (diameter = 1.5 mm) and a glass cylindrical protective sheath (outer diameter = 4 mm; glass thickness = 1.2 mm) surrounding the core electrode. The area of the core electrode in the cross-sectional area of the electrode was 14%, the area of the cylindrical protective sheath body was 84%, and the area occupied by the gap was 2%. The voids were filled with air or a fluorine-based inert liquid (Fluorinert; 3M Company, USA).
In addition, an electrode was manufactured from an aluminum core electrode (diameter = 2 mm) and a glass cylindrical protective sheath (outer diameter = 4 mm; glass thickness = 0.8 mm) surrounding the core electrode. The area of the core electrode in the cross-sectional area of the electrode was 25%, the area of the cylindrical protective sheath body was 64%, and the area occupied by the gap was 11%. The voids were filled with air or a fluorine-based inert liquid (Fluorinert; 3M Company, USA).
About each of these electrodes, the test voltage 18 kV (constant) or 18.5 kV (constant) was applied by the method shown in FIG. 8, and the electrode destruction test was implemented.
[0033]
(2) The results are shown in Table 2 below.
[Table 2]

As a result of the test, it was found that the electrode having the glass area ratio of the protective sheath body of the high voltage side electrode of 84% has a much longer life than the electrode of 64%.
[0034]
【The invention's effect】
According to the present invention, it is possible to extend the life of the gas excitation electrode and achieve cost reduction. In particular, the life of an electrode having a relatively inexpensive glass sheath can be extended.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a part of a side wall of a housing of a protective electrode type gas excitation device in which an electrode of the present invention can be used.
2 is a schematic cross-sectional view of the protective electrode type gas excitation device of FIG. 1. FIG.
FIG. 3 is a schematic cross-sectional view showing the basic structure of a protective electrode type gas excitation device.
FIG. 4 is a schematic cross-sectional view showing the basic structure of the device of the present invention.
FIG. 5 is a schematic perspective view showing a part of a side wall of a housing of an exposed electrode type gas excitation device in which the electrode of the present invention can be used.
6 is a schematic cross-sectional view of the exposed electrode gas excitation device of FIG.
FIG. 7 is a cross-sectional view schematically showing the structure of a gas excitation electrode according to the present invention.
FIG. 8 is a perspective view schematically showing a method for carrying out a destructive test of a gas excitation electrode.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Housing; 1A, 1B ... Support wall; 2 ... Inflow opening part;
3 ... opening for discharge; 4A ... protective electrode;
4A-10, 4A-20 ... protective electrode array;
4a-11, 4a-12 ... protective electrode group;
4a-21, 4a-22 ... protective electrode group;
4B ... exposed electrode; 5 ... core electrode; 6 ... cylindrical sheath;
7A, 7B ... Electric wires; 8, 48 ... AC power supply; 10 ... Gas excitation device;
40 ... Electrode for gas excitation; 40A ... Protective electrode to be tested;
41, 41A ... cylindrical core electrode; 42, 42A ... cylindrical insulator sheath;
43: Gaps; 45 ... Terminals; 50 ... Gas excitation device;
51 ... Housing; 52 ... Inflow opening;
53 ... opening for discharge; 54 (54A, 54B) ... protective electrode;
55 ... core electrode; 56 ... cylindrical sheath; 57A, 57B ... electric wire;
58 ... AC power supply; 60 ... Cutter; 61 ... Cutter blade;
62 ... end of cutter;
G: treated gas; C: treated gas.

Claims (4)

A gas excitation electrode comprising a cylindrical core electrode and a cylindrical insulator sheath surrounding the cylindrical core electrode, wherein the cylindrical insulator has an area of a circle of a cross section of the electrode. The electrode described above, wherein the sheath has a cross-sectional area of 70% or more. The electrode according to claim 1, wherein the cylindrical insulator sheath is made of glass. The cross-sectional area which the space | gap part of the said cylindrical core electrode and the said cylindrical insulator sheath occupies is 2 to 30% with respect to the area of the circle | round | yen of the cross section of the said electrode. electrode. The electrode according to any one of claims 1 to 3, wherein air is filled in a gap between the columnar core electrode and the cylindrical insulator sheath.

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