SIS loop independence issue
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There is an SIS loop: when the pressure is high, the interlock activates the butterfly valve to release pressure; when the pressure is low, the valve is opened to supply air. The same pressure transmitter, the same valve. There’s always something that feels off. Please ask an expert to analyze it.
Is the pressure relief and pressure restoration done by the same valve, on the same pipeline?
Is the pressure relief and pressure restoration done by the same valve, on the same pipeline?
1. What is the safe position of the valve when it has lost air pressure? Should it be opened? Should it stay closed? 2. According to you: both pressure H and pressure L need to be activated in sequence, with the intermediate pressure valve closed (like a breather valve). Is the point at which pressure is released and the point at which pressure is replenished the same device?
There’s nothing wrong with that, but are you saying that a butterfly valve can function as a three-way valve? Is there such a butterfly valve?
High pressure and low pressure are two scenarios. So I think it’s independent.
Shouldn’t there be one intake valve and one exhaust valve? How does a valve work? Three-way valve?
Reserving seats in advance seems achievable to me.
Is this analysis correct? Can’t it be reduced within process control? How can it return to a state of intrinsic safety when in danger?