Radiation power emitted from Ar torch short plasma as a function of in-putpower in several kW

When the waste would be reduced by the are plasma, the radiation power shou ld be put down, because it is a great deal of loss. On the other hand, we c an use it as a clean source for heating materials in a vacuum chamber. In t his case, it is expected that the radiation becomes greater. In both cases the radiation power emitted from the are plasmas has to be precisely contro lled. We measured the radiation power emitted from a plasma torch as a func tion of the electric in-put power. The radiation power was measured to be 2 00-700 W for an in-put power of 2-4.4 kW and increased in proportion to the 1.8th power of the current or near 1.6th power of the in-put power. Theref ore, the radiation power increases steeply with the in-put power. The radia tion efficiency for a wall-stabilized are model was 31% in the condition of 2 cm appearance plasma length, 100 A current and 4400 W in-put power. An e quipment using a vacuum chamber for the plasma treatment of the hazardous w astes due to the radiation power emitted from torch plasma is proposed. (C) 2000 Elsevier Science Ltd. All rights reserved.