Installation of control valve assemblies
Thread Content
According to requirement 10.3.7 of the \"SH3012-2011 Code for Design of Layout of Metal Piping in Petrochemical Industries\", it is specified that during the installation of valve assemblies, the shut-off valves should not be installed in a straight line with the control valves. In my opinion, this is done to prevent the shut-off valves from causing turbulence in the fluid flow, which could lead to unstable operation of the control valves. What are other possible reasons? Is this understanding correct?
Copy Haiyou’s previous answer. The reason why two shut-off valves and a control valve should not be arranged in a straight line is that during maintenance on the straight pipe section, the forces resulting from thermal expansion and contraction of the pipeline are concentrated at the flanges used for operation, which can prevent the control valve from being removed or result in the flanges being far apart when reinstalling it (by several dozen millimeters). At the same time, flanges with uneven surfaces or tenon-and-socket joints require some clearance for the pipes to operate; it is difficult to align two such flanges in a straight line, but it becomes much easier when a elbow is used, as the two flanges are no longer in a straight line. I asked before as well, and their reply was that it’s not convenient for on-site installation