| 摘要 |
PROBLEM TO BE SOLVED: To provide a top-blown lance for blowing into molten metal which can smoothly supply cooling medium into a furnace separately from oxidizing gas and cooling water in a comparatively simple structure without needing larger size than the conventional triple tubes. SOLUTION: The top-blown lance 4 for blowing into the molten metal is composed of an inner tube 12 for supplying the oxidizing gas, an middle tube 13 for forming a supplying path 2 of cooling water for cooling the inner tube 12, an outer tube 10 for forming a drainage path 3 of the cooling water and a nozzle 5 fitted to the lower end of the inner tube 12 and blowing the oxidizing gas into the molten metal held in a converter type reaction vessel. In such a case, plural tube bodies 14 for forming the flowing path of hydrocarbon base cooling medium 8 are disposed in mutually parting state between the outer tube 10 and the middle tube 13 and opened toward the outside of the outer tube 10 in each tube body, and a sub-nozzle 11 for spouting the cooling medium to the outside of the lance, is fitted.
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