Plasma torch, plasma spraying device, and method for controlling plasma torch

A plasma torch that rotates a generated plasma along a central axis, ejects the plasma in an axial direction, melts powder of a thermal spraying material with the plasma, and expels the molten powder from a front nozzle opening, the plasma torch comprising:

• a first electrode formed in a cylindrical shape having a first through hole extending in the axial direction at a center, the first electrode having a first discharge surface continuously formed around a front end of the first through hole;
• a second electrode formed in a cylindrical shape having a second through hole extending in the axial direction at a center and located on a front side of the first electrode, the second electrode having a second discharge surface continuously formed around a rear end of the second through hole so as to face the first discharge surface of the first electrode;
• a first magnet provided on a rear side of the first electrode opposite to the first discharge surface;
• a second magnet provided on an outer periphery of the second electrode;
• a third magnet provided on a front side of the second electrode opposite to the second discharge surface;
• a fourth magnet provided on an outer periphery of the first electrode and facing the second magnet in the axial direction;
• a thermal spray material introduction pipe slidably provided in the first through hole along the central axis, that supplies thermal spray material powder from a supply port to a discharge space formed between the first electrode and the second electrode;
• and
• a plasma generation gas supply passage that supplies plasma generation gas to the discharge space from the outer peripheral side of the first electrode,
• wherein a vector, of current flowing between the first discharge surface of the first electrode and the second discharge surface of the second electrode to generate the plasma, and a vector, of magnetic flux of a combined magnetic field generated by the first magnet, the second magnet, the third magnet, and the fourth magnet, are orthogonal.