I would like to ask about the usage method of the pressure relief valve assembly
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This is a pressure relief valve assembly on the nitrogen line leading to the tank area; it is used for nitrogen sealing of several tanks once inside the tank area. The blue one in the middle should be the pressure relief valve, right? There is a gate valve on each side of the pressure reducing valve. I observed that the personnel in the tank area kept both gate valves open, using the pressure reducing valve in between to control the flow rate. Is this method of operation correct?
That’s right; the inlet and outlet gate valves are used only for shutdown during maintenance. There should be a bypass valve; that’s what constitutes a set of pressure relief valves.
There should be an additional bypass pipe outside the two stop valves, with a gate valve on that pipe. Only in this way can a valve assembly be formed; during normal operation, the gate valves on both sides of the pressure reducing valve remain open, while the cross-line gate valve remains closed. With the pipeline still in operation after replacing the pressure reducing valve, open the cross-line gate valve and close the gate valves on both sides of the pressure reducing valve, then replace the pressure reducing valve.
Okay, I understand. Thank you for the guidance
Correct, the inlet and outlet gate valves are only used to shut off the pipeline during maintenance