In the face of so many valve classifications and so complex various working conditions, to choose the most suitable valve product for pipeline system installation, we should first understand the characteristics of the valve; Secondly, we should master the steps and basis of selecting valves; Moreover, the principle of selecting valves for petroleum and chemical industries should be followed.

The principle of selecting valves in petroleum and chemical industry: the flow passage is a straight through valve with small flow resistance, which is usually used as the cut-off and opening medium; The valve easy to adjust the flow is used to control the flow; Plug valve and ball valve are more suitable for reversing and shunting; The sliding of the closing piece along the sealing surface with wiping effect is most suitable for the medium with suspended particles.