GB1276930A - Improvements in and relating to plasma apparatus - Google Patents

Abstract

1276930 Plasma apparatus N A CHESNOKOV G P STELMAKH A S SAKHIEV and N N RYKALIN 3 June 1969 28005/69 Heading H5H Plasma apparatus, for effecting chemical or physical transformations of materials in particulate, gaseous or liquid form, comprises a plasma torch 1 mounted so that a plasma jet 2 therefrom coincides with the axis of an annular cross-section anode 3 or 11 and serves as a non- eroding cathode for producing a distributed discharge region 6 within a magnetic field, e.g. of a solenoid magnet 5. The anode is a cylinder 3, or a conical spiral 11, or a cone 9, Fig. 2 (not shown), and the discharge fills the region 6 within the anode. A device 7 for feeding in a cold quenching gas is provided beyond the region 6. A triggering device 28 initiates a discharge between the cathode 16 of torch 1 and an auxiliary anode 19 for ionizing the gas passed through the cooled insulated sections 21 of the torch. Power from a source 13 applied to torch anode 18 then results in generation of the plasma jet 2 to serve as gas cathode for the diffuse or glow discharge in region 6. Prior to triggering the apparatus is evacuated and then a plasma-generating gas at 10 mm. pressure is fed in. When the discharge is established in region 6, the materials to be processed are fed in via tube 30. The electromagnet 5 is energized from a separate power source 27, or from source 13 for torch 1, or from power source 25 for generating the discharge of region 6, source 25 being a D.C. or A.C. generator. Current connection from source 25 to the gas cathode 2 is via the torch anode 18 or via a separate contact ring 24, Fig. 4 (not shown). The conical spiral anode 11 is non-magnetic and co-operates with the cooled magnetic casing 12 to provide the magnetic field for region 6. This embodiment operates at higher pressures, the diffuse discharge pinching to form an arc between the base of cathode 2 (anode 18 of torch 1) and a turn of the anode 11, the arc rotating and travelling along the anode towards its converging end. Additional shunting arcs arise simultaneously on the other turns of the spiral, travelling in a similar manner to the first arc and thus filling the region 6 with a plasma discharge. The torch 1 of Fig. 3 differs from that of Figs. 1, 2, by having a dielectric interelectrode insert 21<SP>1</SP>.