Regarding PID flowcharts
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Gentle experts, I’m a beginner. What does the circled area in the image represent? Please let me know.
Gauge isolation valve bank. The valve below breaks the connection with the pipeline, while the valve above releases the pressure between the valve below and the pressure gauge, preventing a bang when the pressure gauge is removed~
The two valves in the square should be integrated.
This design is somewhat more clever – the vent is integrated with the pressure gauge
Thank you, I understand a bit more now; it’s really educational. I also want to ask you what PG and PIG stand for respectively. Thank you
Instrument valve assemblies often have several interfaces for various connections.
I’ve really never seen a PIG used; in normal companies, when the same point on a PID requires pressure measurement both at the local level and remotely, a separate PI and PG are used.