Isolation valves and control valves
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I would like to ask how to determine in a PID diagram whether it is an electromagnetic pneumatic diaphragm shut-off valve or a control valve
On the first few pages of a PID diagram, there are legends; it’s important to develop the habit of checking these legends when looking at such diagrams. In well-designed diagrams, the legends are quite detailed, and notes are provided on that page for any special symbols
The tag numbers of on-off valves and control valves are different, as are their legends, as well as the signal points they generate.
In general, design institutes use circular die heads for control valves and flat die heads for on/off valves; moreover, many control valves also have a shut-off function
For example, the shut-off valve XV, the control valve FV