In testing process, formation fluid must be led into separator and combustor in a controlled way after flowing to the ground through drill pipe or oil tube. This device is called ground control device, which can control fluid pressure and flow safely and effectively.
 

Control head is connected to the top of testing string, and falls into rotary and irrational. It can be divided into three kinds of pressure, which are 35MPa, 70MPa and 105MPa. Control head can not only drain the high pressure liquid flow in pipe column, but also pump fluid into well. 

 It is used to connect control head, drill floor pipe and the high pressure movable manifold of relief line. It is composed of specially-made ever-thicker seamless steel tube ,unions and elbows.