CHARACTERIZATION OF A TWIN-TORCH TRANSFERRED DC ARC

The results of a twin-torch transferred dc arc study are presented. The arc system consists of two torches of opposite polarity and a coupling zone of plasma jets located between them. The torch configuration increases the system reliability and efficiency during material plasma processing. The results of the study present data for the voltage-current characteristics, general behavior of the twin-torch arc, and spatial distribution of the plasma parameters. The plasma parameters have been measured using optical emission spectroscopy for a 200 A (20 kW) dc are at atmospheric pressure, with argon and nitrogen introduced as plasma-forming gases into the anode and the cathode units, respectively. The measurement technique used has allowed the determination of local electron density and temperature values in an inhomogeneous plasma volume having no axial symmetry. The data obtained illustrate the novel features of the twin-torch transferred dc arc for its applications in plasma processing.