PURPOSE: To prevent sputters generated associated with the plasma torch processing from fusion attachment to a nozzle by covering it with a cap; to reduce the costs by replacing minimum amount of components when the cap is damaged by sputters.
CONSTITUTION: Plasma arcs generated by electric discharge between an electrode 20 and a work to be processed are spouted out of orifices 21, 23 formed in a nozzle C, wherein a cap D is provided which is secured to a torch body in touch with a tapered portion 24c formed at the tip of the nozzle C where a hole 32d some greater than the orifice 23 is formed while confronting the orifice 23 formed in the nozzle C. The cap D is composed of a covering member 32 positioned as mating with the nozzle C and a cap body 31 to which the covering member 32 is mounted removably. At least the contact surface of the covering member 32 with the nozzle C or the contact surface of the outer nozzle member 24 with the covering member 32 are coated with a ceramic material and ethylene tetrafluoride resin so that electrical insulation is applied.
KOJO AKIRA
OBARA HIROTAKA
