Tuyere for metallurgical vessels

Claim 1

A process for operating a refractory lined refining vessel for the refining of molten metals, wherein at least one stream of refining gas is introduced into a bath of molten metal in said vessel, said refining gas being introduced into said metal together with a sheath of protective media surrounding the stream of refining gas, through a multiple pipe tuyere, and wherein, as a result of the introduction of said refining gas, the mouth of the tuyere and the refractory lining adjacent to the mouth of the tuyere become eroded, threatening the useful life of the refining vessel, the improvement which comprises providing a tuyere which includes a sheath pipe embedded in the refractory lining of the refining vessel and at least two pipes axially slidable inside said sheath pipe for introducing said refining gas and said protective medium into said bath, and after said refractory lining and said tuyere have been eroded, advancing said axially slidable pipes into said vessel so that they extend into the vessel and project beyond the refractory lining, and applying refractory to build up the worn away lining at least to about the distance to which the axially slidable tuyere pipes project into the vessel.