Regarding the opening and closing status of the inlet and outlet valves of the TRV under normal operating conditions
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Hello, everyone! TRV (Thermal Relief Valve): I read in a set of operating procedures that under normal operating conditions, the inlet and outlet valves of this type of valve are closed, and they are opened only during maintenance or shutdown. Isn’t that very dangerous? Please discuss this. :)
I can’t understand why the valves before and after the TRV are closed; they should be open. Otherwise, what will happen due to thermal expansion? How can pressure be released?
I think so too. What’s the flow rate of this type of valve generally?
It is used when the pipeline is not emptied regularly and there is a risk that the valves at both ends might be accidentally closed. It depends on the length of the pipeline you want to protect; I haven’t done any specific calculations yet. For our DN200 pipelines, which are about 100 meters long, we use DN25 TRVs
Is its internal structure very different from that of a regular PSV?
I’m sorry, I haven’t opened it to take a look; I think it’s the same thing – the overpressure caused by temperature ultimately leads to pressure release