Patent ID: 6498317
Filing Date: 2002-12-24
Classification: B23K,G06F,H05H

Abstract:
A process for starting a plasma torch, 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 cutting 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 start up process comprising:increasing an arc current at a first upslope rate for a first time interval (t2 to t4); introducing an operational nozzle gas flow and pressure at t3; increasing the upslope rate of the arc current increase during a second time interval (t4 to t5), said upslope rate increase thereby regulating the nozzle flow to prevent the nozzle flow from exceeding an operational flow rate Fo during start up; and, establishing an operational arc current and an operational nozzle flow rate.