Plasma torch of high cooling performance and components therefor

摘要

An object is to provide a plasma torch having a function to achieve fully satisfactory cooling of the nozzle and shield cap. A plasma torch 1 comprises a nozzle 17 positioned at the front end portion of the torch 1 so as to cover an electrode 13, with a plasma gas passage 37 interposed therebetween. A shield cap 21 is mounted at the front end of the nozzle 17, and these components 13, 17 and 21 are accommodated in a retainer cap 23. Assist gas passages 45, 55 are formed in the wall of the retainer cap 23, and feed assist gas to the vicinity of the plasma arc 81. A space enclosed by the retainer cap 23, nozzle 17 and shield cap 21 is a cooling water passage 63. The retainer cap 23, nozzle 17 and shield cap 21 faces the cooling water passage 63, and hence directly and powerfully water-cooled.