Identification in PID diagrams
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I would like to ask the experts: what do the several valves marked in red on the PID diagram represent? The context is the path from the high-pressure separator to the low-pressure separator
1 is the orifice plate flow meter, 3 is the cylinder valve; the two sets of vertical lines at each end likely represent flanged valves, and 45 is a vent valve equipped with a flange cover.
1. Throttling orifice plate； 2. It should be a mark of 3, I’m not sure about this ； 3. It is a pneumatic valve, which uses instrument air as power to open and close the valve ； 4 and 5. In our factory, these are called drain guides; they have blind caps (flange caps) on top, which are likely used for draining or purging the pipelines during startup and shutdown ； 6. As can be seen from the diagram, it is likely a dual-valve assembly; CSO indicates that the valve needs to remain open at all times, and it should be sealed with a lead seal ； One needs to go to the site in person or check the schematic diagram; dual valve assemblies are usually placed very close to each other. If they are far apart, it might be a regular shut-off valve. It’s not certain though, hehe ； I’ve been at the factory for not long yet; this is just for reference, hehe ；
The first one, I don’t think it’s a orifice plate; it might be a blind plate locator. In other words, normally it’s an open plate, and there’s a corresponding blind plate stored in a warehouse or somewhere else, which is installed when needed by removing the open plate and replacing it with the blind plate.