| 摘要 |
A submerged lance (1) for injecting treatment agents into a bath of molten metal contains a central injection tube (3), a jacket tube (5) arranged concentrically and with a clearance around the injection tube, and a heat exchanger space (6) between these two tubes, through which there flows a heat exchanger fluid. The jacket tube (5), which is formed essentially by a metal tube (9), is provided with a refractory covering (10) at least on its immersed longitudinal portion, while the heat exchanger space (6) is divided by a concentric intermediate tube (12) into a feed space (6a) and a removal space (6b) for heat exchanger fluid; a control device (22) for feeding (18) and removing (20) the heat exchanger fluid is also provided. This submerged lance, which is of simple construction, makes possible reliable feeding and removal of the heat exchanger fluid at all times and reliable heat exchange between the latter and the corresponding parts of the lance. <IMAGE>
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