| 摘要 |
This element comprises: - a refractory mass 2, the said mass being perforated axially by a passage 3 joining the upper and lower faces for the flow of the metal; - a lateral casing 10 surrounding the said refractory mass at a short distance so as to define, between them, a narrow blowing space 8 emerging, at one of its ends, on the upper face of the refractory mass; - spacing means for maintaining the desired separation between the casing and the refractory mass; - and means 12, 13, 14 for joining the said space, via its other end, to a source of pressurised fluid, such as nitrogen or argon. <IMAGE>
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