Patent ID: 6849228

Claim:
Blow-lance nose intended for stirring baths, comprising a central tube for supplying stirring gas, closed at one end turned towards the bath by a first front wall provided with at least one opening, an internal tube forming with the central tube a first annular cavity for the passage of a cooling liquid and closed at one end turned towards the bath by a second front wall having a central opening and one passage orifice per opening provided in the said first front wall, an external tube forming with the internal tube a second annular cavity for the passage of the cooling liquid and closed at one end turned towards the bath by a third front wall having one outlet orifice per opening provided in the said first front wall, a heat exchange space which is situated between on the one hand the said second front wall and the said third front wall and on the other hand the said central opening and the said second annular cavity, and in which the cooling liquid flows, and an outlet conduit for the stirring gas leaving each opening in the said first front wall and going as far as an aforementioned corresponding outlet orifice, passing through an aforementioned corresponding passage orifice in a manner which is impervious to the cooling liquid, wherein the said third front wall has a central depression which is directed towards the said central opening and which has a ratio between height of depression and base of depression equal to or greater than 0.35, and in that the aforesaid heat exchange space has a cross-section for the passage of the cooling liquid which is substantially constant, so as to obtain a speed of passage of the cooling liquid through this space which is approximately constant, in the presence of the said depression.