Normal open and emergency open of the valve
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When purchasing pneumatic valves, some manufacturers require that it be specified whether the valve is normally open or normally closed, while others require indication of whether it should open in an emergency or close in an emergency. Are these two things the same?
In principle, it should be the same thing – both involve a power outage and the state of the valve when there is no air supply
It’s different. Normal open means it opens in case of an accident; the status is different
It’s the same, just with different titles.
Pneumatic valves do not have a normally open or normally closed state; they only operate in modes of opening when air pressure is lost, closing when air pressure is lost, or maintaining their position when air pressure is lost. Normally open or normally closed is a concept in electrical engineering.
Node signals have the concepts of normally open and normally closed. Control valves are generally air-operated for normal operation, or fail-operated in case of an accident
Literally speaking, if the valve is in accident open mode, it remains in a closed state; if it is in accident close mode, it remains in an open state. What was said on the 5th floor is correct.