Control Valve and Flange Question


Thread Starter

Irfan Choudary

dear friends,

i have one question regarding control valve. can you give me this question answer. why use the reducer before control valve flanged? i have seen many control valves in industry they used reducer before control valve.
Because process piping is frequently oversized for the needed flow range, a correctly sized valve will frequently have a smaller valve body size than the line size.

Since the purpose of a control valve is to use up or take out energy in the flow stream (create a pressure drop), using a valve body smaller than the line size just works towards that end.

Asok Kumar Hait

David is right. However, just to mention here that if the control valve size is equal to the pipe size that doesn't mean that the valve sizing is wrong. For a particular flow valve size depends on the pressure drop considered across the valve. Depending on the pressure drop considered across valve, the selected valve may be equal or less than the pipe size. Majority of the cases valve size is less than the pipe size.