Apparatus for the controlled feeding of a refining gas and of a fluid protective medium

In an apparatus for supplying a refining gas and for supplying a fluid protective medium individually to each of a plurality of tuyeres mounted in the refractory masonry of a refining vessel each of said tuyeres consisting of at least two concentric pipes with separate supply lines to supply said refining gas and to supply said protective medium, the refining gas passing through the center pipe and the protective medium passing through the annular spaces between said concentric pipes;

• and including a control valve (3) in the supply lines (1) through which said protective medium is supplied to each of said tuyeres, a pressure reducing valve (4) in each of said supply lines in series with said control valve (3), and a back pressure valve (5) between each of said tuyeres and each of said pressure reducing valves in each supply line of said protective medium, and
• the improvements which comprise:
• means to control each of said pressure reducing valves (4) said means comprising a pressure transmitter (7) operatively connected to a by-pass line (11) of said main refining gas supply line (16) and said pressure transmitter (7) transmitting the pressure fluctuations of the refining gas line to each of the pressure reducing valves (4) mounted in each of said protective medium lines, whereby the pressure of said protective medium flowing to said tuyeres is individually controlled and changed by the pressure reducing valves (4) in relation to the refining gas pressure in such a way that the pressure in each of said protective medium lines cannot exceed the pressure in the refining gas line.