Does anyone know anything about the accident switch?
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As the title suggests, how are accident switches (FC and FO) generally used? Are they automatically turned on and off only in the event of an accident? Why do I see that they can also be manually controlled on our P&ID diagrams? Additionally, what type of switches are these usually?
In our city, as for the accident buttons, I’m not sure if they are the ones you’re referring to. When an accident occurs, it is classified into several levels, and by pressing different buttons, the equipment will take corresponding actions through the system based on the button you press. (It was originally automatic in the system, but due to too many false failures, it became impossible to switch to a manual method.) ) This post was last edited by hbzy on 2008-10-28 14:10 ]
1. FC refers to the situation where, in the event of a loss of air supply (for pneumatic valves) or a power failure (for electric valves), the actuator automatically moves the valve’s core to the closed position. 2. FO refers to the situation where, in the event of a loss of air supply (for pneumatic valves) or a power failure (for electric valves), the actuator automatically moves the valve’s core to the open position. 3. FL refers to the situation where, in the event of a loss of air supply (for pneumatic valves) or a power failure (for electric valves), the actuator automatically keeps the valve’s core in its current position, that is, in a held state. Apart from the several individual cases mentioned above, it can also be a combination of 1 and 3 or a combination of 2 and 3 – either option will work! This post was last edited by hbzy on 2008-10-28 14:12]
When the emergency switch is activated, other buttons (such as the start button) become inactive. This prevents the moving equipment from operating accidentally during accident handling.
The explanation on the 4th floor is correct. It represents the safe position allowed by the process in the event of a failure of the control valve.
What was said on the 4th floor is correct... FC and FO refer to fault off and fault on
I see, I’ve had doubts about this before as well
Regarding FC and FO, several of us discussed this issue today, and I eventually asked the supervisor: FC and FO refer to emergency switches, but it doesn’t mean that they cannot be operated under normal conditions; rather, it is for safety reasons that the valve is opened or closed. For example, the anti-surge valve of the main fan unit that we are discussing today. It’s FO, accident start. . . . Protect the crew.
To be precise, it should be the allowable position of the valve in a faulty condition. The fault is merely an air supply issue