| 摘要 |
A coherent jet lance (3 fig 2) has a lance face 6 and at least one nozzle opening 4 surrounded by a first ring of ports 30 and a second ring of ports 31 radially spaced but aligned with respect to the first ring of ports. Fuel is provided from one ring of ports and oxidant from the other ring of ports in order for combustion to occur, and the at least one nozzle provides a coherent gas jet. The lance face is extensionless and therefore in operation does not form a recirculation zone. The gas jet may exit at supersonic velocity, and the fuel and oxidant flow from the ring of ports may be sonic or supersonic in velocity. The gas jet emitted from the lance may be used to treat molten metal, and the coherent gas jet may travel a distance equivalent to at least 20 nozzle diameters. When a plurality of nozzles (2 fig 2) is used, these may be aligned at a divergent angle with respect to the lance centreline. The gas jet may be oxygen, nitrogen, argon, carbon dioxide, hydrogen, helium, steam, a hydrocarbon, or mixtures thereof. |
