Whether a bypass is needed for the control valve
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In our facility, basically none of the control valves are equipped with bypasses. During our routine inspections and maintenance checks, we raised this issue with the design institute, which replied that their control valves would not fail, so bypasses were not necessary. Do we really need to have a bypass? On the one hand, it is to prevent the control valve from breaking down and failing to function ； The first reason is to eliminate the difference between the design value and the theoretical value.
Control valves generally require bypasses – you must have turned to an inferior design firm! Unless those that are not used frequently can be equipped with a handwheel for operation ； For applications with high precision requirements, where safety and environmental protection are at stake, a bypass may not be necessary.
The control valve requires a bypass to be installed； However, if the control valve is truly not faulty, it may not be necessary to install it; this requires a guarantee from the design institute...
A few days ago, a crack suddenly appeared in our instrument air line; without a connection to the air valve, stopping the supply of instrument air would force a shutdown of the operation.
A bypass valve should be installed.
High-pressure systems rarely have bypasses designed~~~
The bypass is provided to facilitate the maintenance of the control valve. Who can guarantee that the control valve will never have any problems? Even if the control valve itself is of high quality, issues may arise with the air supply system or other accessories. However, bypasses are not installed in some special situations, such as the compressor anti-surge valve and the valves inside the air separation cryogenic tank.
It depends on the user’s requirements, as well as factors such as the adjustment accuracy and whether integrated control is needed. For our applications, we require a high level of adjustment accuracy, and since PID control is used, there is no bypass system. There is also the option to manually adjust it in case it gets damaged, so no bypass circuit was designed.
Who can guarantee that the control valve won’t break? If it does, production has to stop for repairs, resulting in losses for the company – who will be responsible for those losses? It doesn’t seem scientific. .