Patent ID: 6677551
Filing Date: 2004-01-13
Classification: B23K,H05H

Abstract:
A process for operating a plasma torch on shut down, the plasma torch having a plasma gas chamber supplied with a plasma gas, an electrode supplied with current for generating a plasma cutting arc by ionization of the plasma gas, and a nozzle disposed in front of the electrode through which the plasma cuffing arc extends to a workpiece, in an operational cutting mode of the torch the plasma gas within the plasma gas chamber having a swirl component imparted thereto by a swirl ring, said process comprising:providing an aluminum jacket surrounding the sidewalls of an electrode element; decreasing the arc current to the electrode from Io to a lesser intermediate value during a time interval from t0 to t2, thereby lowering the temperature of the electrode element; decreasing the nozzle flow rate from t0 to t2 in a substantially proportional correlation to said decreasing arc current; and, shutting off current to the electrode at about t2.