PID diagram help! What is the difference between the two black and hollow ball valves in the picture?
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As shown in the picture, the ball valve on the left is black, and the ball valve on the right is white and hollow. What is the difference between these two valves?
What is the difference between AA532 and AA013 valves? Is it a different way of connecting the pipes or is it for distinguishing and eye-catching identification? Sincerely seek help~
The white one means that it is always on during normal operation, and the black one means that it is always off during normal operation. Some design institute PIDs will say this. Personally, I think it is unnecessary. It is just a waste of printing toner.
One flange connection and one welded connection. As for black and white, one is always on and the other is always off. See the legend for details
The third and fourth floors made it very clear that valves are marked as normally open and normally closed. There are also markings NO and NC to represent normally open and normally closed. Different design institutes have different characteristics.
The third and fourth floors made it very clear that valves are marked as normally open and normally closed. There are also markings NO and NC to represent normally open and normally closed. Different design institutes have different characteristics.
Different colors represent different switching states of the valve