PROBLEM TO BE SOLVED: To easily change an electrode in a plasma generating nozzle generating NO2 gas.SOLUTION: A plasma generating nozzle 31 has an inner electrode 35 and an outer electrode 36 arranged concentrically. Micro-waves propagated via a waveguide 62 are received by the inner electrode 35 to generate glow discharge between the electrodes 35 and 36, and air supplied between the electrodes 35 and 36 is plasma-processed to generate NO2 gas. To allow changing of the inner electrode 35 to be worn, the inner electrode 35 is held by a holding member 37 made of a material with an insulating property and formed into a cylindrical shape. When a space between an outer periphery of a holding member 37 and an inner periphery of the outer electrode 36 is sealed with an endless annular seal member 373 such as an O-ring to prevent the leakage of the processed gas, the seal member 373 is fitted into a recessed groove 3711 formed in a circumferential direction on the holding member 37 side. Thus, the seal member 373 can be removed together with the holding member 37.COPYRIGHT: (C)2013,JPO&INPIT【課題】NO2ガスを生成するプラズマ発生ノズルにおいて、電極交換を容易にする。【解決手段】同心状に配置される内側電極35および外側電極36を有し、導波管62を介して伝搬されるマイクロ波を内側電極35で受信することで電極35,36間にグロー放電を発生させ、電極35,36間に供給される空気をプラズマ処理してNO2ガスを生成するプラズマ発生ノズル31において、損耗する内側電極35を交換可能にするために、該内側電極35を、絶縁性を有する材料から成り、円筒状に形成される保持部材37によって保持する。そして、保持部材37の外周面と外側電極36の内周面との間を、処理されたガスが漏れないようにOリングなどの無端環状のシール部材373でシールするにあたって、そのシール部材373を保持部材37側の周方向に形成した凹溝3711に嵌め込むようにする。したがって、保持部材37ごとシール部材373を取り外せる。【選択図】図7
