| 摘要 |
PURPOSE:To prevent magnetic powder from sticking to an orifice by providing a coil to melt the magnetic powder by a plasma arc and generate a magnetic field in the direction of a plasma arc column around the orifice to discharge it from the lower part of the orifice. CONSTITUTION:Inert gas is supplied from a supply pipe 27 to fill the inside of an arc restrained nozzle 22 and is discharged from the orifice 28 of the lower part. In this state, a pilot arc is generated between a tungsten electrode 21 and the arc constrained nozzle 22. Next, the inert gas is supplied from a pipe 37 and shielded sufficiently and a straight polarity main arc is generated in an interval with base metal. Next, in a state that an electric current is allowed to flow to the coil 26 so that its lower part is made to an N pole, the magnetic powder is sent in by mixing it in the inert gas from pipes 23a and 23b. The magnetic powder is attracted in the direction of the plasma arc column by the magnetic field generated by the coil 26 and molten by the plasma arc without sticking to the vicinity of the orifice and made to a nonmagnetic material and discharged without being influenced by the magnetic field of the coil 26.
|
