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Progress in Plasma Processing of Materials, 1999

ISBN:
1-56700-126-2 (Print)

INDUSTRIAL TRANSFERRED ARC PLASMA TORCH FOR METALLURGICAL APPLICATIONS

Mihail K. Mihovsky
“PLASMALAB” - Plasma Metallurgy Research Laboratory, University of Chemical Technology and Metallurgy - Sofia, 8 “Kliment Ohridsky” Blvd., 1156, Sofia, Bulgaria

Tzonio P. Tzonev
University of Chemical Technology and Metallurgy, PLASMALAB, 1156 Sofia, 8 Kl. Ohridsky Blvd., Bulgaria

Biserka I. Lucheva
University of Chemical Technology and Metallurgy, PLASMALAB, 1156 Sofia, 8 Kl. Ohridsky Blvd., Bulgaria

Abstract

The industrial metallurgical transferred arc plasma torch for metallurgical applications has been designed and manufactured by PLASMALAB for continuous operation in a 2.5-tons plasma-induction furnace at Kremikovtsi Ltd. The plasma torch parameters are: Maximum working transferred arc current - 3000 A; maximum non-transferred arc current - 400 A; plasma gas (argon, nitrogen or their mixture) flow rate - 7-16 m3/h; plasma gas pressure - 0.4 MPa; cooling water flow rate 6-10 m3/h; cooling water pressure - 0.6-1.0 MPa.
The main units (cathode and anode) are shown as drawings and the construction features are described: Original design of easily removable water-cooled copper nozzle; original design of nozzle sealing in plasma torch body placed in the furnace at high temperature; easily removable thoriated or lantanited tungsten cathode and possibility for its fine axial positioning and fixing toward the torch nozzle in operation.
Very efficient water cooling and new nozzle and cathode design provide reliable continuous operation of over 300 hours. The plasma torch designed and manufactured by PLASMALAB can be used in any type of plasma melting furnace.