Patent ID: 6657152
Filing Date: 2003-12-02
Classification: B05B

Abstract:
A torch head for plasma spraying which is inserted into a tube member to form a coating on the inner surface of the tube member by plasma spraying, comprising:a torch body which is inserted into the tube member; a cathode tube which is arranged in the torch body such that the longitudinal axis of the cathode tube is aligned to the longitudinal axis of the torch body and which has a cathode at the distal end of the cathode tube; an anode member which is arranged on the distal end side of the cathode tube; and a spraying material supply tube which opens toward a mouth opening formed in the anode member and which is arranged outside the torch body, wherein, in the anode member, a plasma gas supply chamber in which the front end of the cathode tube is present in a non-contact state, an orifice which communicates with the plasma gas supply chamber and in which the cathode is present in a non-contact state, and a plasma generation chamber which communicates with the orifice, which has a longitudinal axis substantially perpendicular to the longitudinal axis of the torch body, and which has the mouth opening are formed, the opening area of the orifice when the anode is inserted is made &frac13; to {fraction (1/10)} of the opening areas of the plasma generation chamber and the mouth opening so that an arc from the distal end of the cathode is generated within a range of 0Â° to 40Â° with respect to the longitudinal axis of the plasma generation chamber perpendicular to the longitudinal axis of the cathode.