ELECTRIC-ARC PLASMATRON Russian patent published in 2004 - IPC

FIELD: electric-arc plasmotrons. SUBSTANCE: proposed plasmatron provided with interelectrode insert is designed for coating or plasma hardening surfaces at difficult-to-get-at places, such as inner surfaces of pipes whose clear diameter is comparable with distances adopted for evaporation (100-300 mm) and can operate on different plasma-forming gases, including active gases (air doped with hydrocarbon gas). Plasmatron has water-cooled end cathode, hollow interelectrode insert electrically insulated on both ends and provided with annular channel communicating with plasma-forming gas source, hollow air-cooled anode, pipe union for feeding plasma-forming gas to gaps between interelectrode insert and anode and between interelectrode insert and cathode, all of them being arranged in tandem. Pipe union used for feeding all plasma-forming gas is connected directly to annular channel of interelectrode insert; additionally installed swirlers function to bifurcate plasma-forming gas stream and are made on interelectrode insert in the form of channels organized by multistart thread with exit on either side of interelectrode insert to gaps between interelectrode insert and cathode and between interelectrode insert and anode; mentioned gaps open to axial (arc) channel of plasmatron; ratio of interelectrode insert length to its diameter is within 0.5-3 and ratio of total cross-sectional area of channels passing plasma-forming gas to gap between interelectrode insert and cathode to total cross-sectional area of channels passing gas to gap between interelectrode gap and anode is within 1-5. EFFECT: enhanced specific power and reduced axial size of plasmatron. 3 cl, 1 dwg