Selection and sizing of control valves for gases and liquids

摘要

Properly sized contorl valves are essential to obtain good process contorl.Simply secifyign a valve size to match an existing pipe size leaves much to chance and will likely create and imporcticla situation in terms of initial investment and adequacy of contorl.Too small a valve will not pass the requried amount of flow,while too large a valve will be unnecessarily expensive and will create instability poroblmes at low flow rates.