| 摘要 |
An improved plasma torch having a rugged configuration, which is easier to start, and which eliminates the need for fragile and possibly metal contaminating insulators from the lower end of the plasma torch. To prevent double arcing from occurring and to enable the elimination of costly insulators from the nozzle area, the electrode and nozzle of the plasma torch of a first embodiment of the present invention are rotated as a unit at a speed in the range of 0 to 400 rpm. In a second embodiment of the invention, the nozzle assembly rotates relative to the electrode which is normally stationary. The electrode and nozzle could rotate in opposite directions as well. When the nozzle assembly is rotated, the resident arc time would be of such short duration due to the spinning of the nozzle that serious damage to the nozzle would not occur. The rotating nozzle can be advanced into an area and, should it strike an unexpected obstruction, the possibility of damage to the nozzle or to the outer electrode area will be greatly reduced or, in most cases, eliminated. The rotating nozzle will also enhance torch starting with a pilot are as the arc transferred from the nozzle to the work piece will transfer from the plasma torch electrode to the work piece when the torch is withdrawn or moved to eliminate the double arcing.
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