| 摘要 |
<p>FIELD CONVERTIBLE PLASMA ARC TORCH Disclosed is a plasma arc torch adapted to operate in the nontransfer arc mode and which is characterized by long electrode life. The torch comprises a torch housing with a rear electrode mounted within the housing and comprising a tubular metal member having a closed inner end and an open outer end. A front electrode comprising a tubular metal member having a bore therethrough is mounted within the housing and in coaxial alignment with the rear electrode and has an inner end adjacent the open outer end of the rear electrode and an opposite outer end. There is vortex generating means for generating a vortical flow of a gas at a location intermediate the rear and outer electrodes and which is in coaxial alignment with the rear and front electrodes. Power supply means is operatively connected to the rear and front electrodes for generating an arc which is adapted to extend axially from the rear electrode through the vortical flow of gas and to an attachment point located on the front electrode. The improvement comprehends the bore of the front electrode including an outer end portion which is cup-shaped in cross section to define an outwardly facing radial shoulder, coordinating the vortex generating means and is coordinated with the power supply means such that the arc attaches on the radial shoulder of the front electrode. The attachment of the arc to the radial shoulder results in erosion of the material of the front electrode along an axial path of travel rather than radially through the elctrode, to thereby extend the life of the front electrode.</p> |
