Plasma torch with a lead-in tube

摘要

PCT No. PCT/NO92/00198 Sec. 371 Date Aug. 12, 1994 Sec. 102(e) Date Aug. 12, 1994 PCT Filed Dec. 11, 1992 PCT Pub. No. WO93/12634 PCT Pub. Date Jun. 24, 1993.A plasma torch has two or more tubular electrodes located co-axially with one inside the other for chemical treatment of a reactant and includes a lead-in tube supplying the reactant and which is located co-axially in the inner electrode; the lead-in tube includes a liquid-cooled tube provided with a heat-insulating layer on the outer surface; the lead-in tube has a longitudinal axis along which the lead-in tube can be moved for positioning the nozzle at its lower end in relation to the plasma flame; the nozzle end is replaceable and is shaped with a conical wall portion to define a venturi passage to increase the exit velocity of the reactant; between the lead-in tube and the inner electrode an annular passage is provided through which plasma-forming gas is introduced which can be used to cool the reactant gas.