Preparation of homogeneous gas mixtures with SF.sub.6

A mixing station for producing a substantially homogeneous mixture of sulfur hexafluoride and nitrogen, said mixing station comprising a first gas line for conveying sulfur hexafluoride from a SF.sub.6 source to a premixing point;

• a second gas line for conveying nitrogen from a N.sub.2 source to said premixing point;
• a static mixer;
• a gas line for conveying a gas premixture from said premixing point to said static mixer;
• a buffer tank;
• a gas line for conveying a gas mixture from said static mixer to said buffer tank;
• a compressor for compressing and homogenizing a gas mixture;
• a gas line for conveying a gas mixture from said buffer tank to said compressor;
• a discharge for discharging a compressed and homogenized gas mixture from said compressor;
• a recycle line connected between said compressor discharge and said buffer tank for recycling a portion of the compressed and homogenized gas discharged from said compressor to said buffer tank, and a control valve connected to said recycle line for regulating the proportion of the compressed and homogenized gas discharged from said compressor which is recycled to said buffer tank.