What are air-open valves and air-close valves?
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I studied pharmacy, and now I work in a factory where ammonia is synthesized. I don’t know what a gas-on valve is or what a gas-off valve is. Thank you!!! This post was last edited by 3300 on 2007-12-7 at 11:28
The so-called \"air-open, air-close\" refers, as the name implies, to the operation of the valve (opening or closing) when the actuator of the control valve is subjected to air pressure (instrument air). In the air-close type (FO): 1. Forward seat (the valve is closed when the valve stem moves downward): air enters the actuation cylinder (diaphragm head) from the upper side； 2. Reverse valve seat (the valve is open when the valve stem moves downward): Air intake for the actuator cylinder (diaphragm head) is at the lower part ； FO: Turn on in case of failure (state when instrument air is cut off)
This is primarily based on safety considerations, namely ensuring that in the event of a loss of instrument air, the control valve operates in such a way as to prevent the system from overheating or overpressuring.
Air-open valve: It opens only when the compressed air pressure is above a certain value; it closes completely when the pressure falls below that value. Air-close valve: It closes only when the compressed air pressure is above a certain value; it opens completely when the pressure falls below that value. In short, an air-open valve closes completely when the air supply is stopped, while an air-close valve opens completely under the same conditions.
The “air” here refers to instrument air; F is the first letter of the word for accident, O stands for open, and C stands for close
Air-open valve: It opens only when the compressed air pressure is above a certain value; it closes completely when the pressure falls below that value. Air-close valve: It closes only when the compressed air pressure is above a certain value; it opens completely when the pressure falls below that value. In short, an air-open valve closes completely when the air supply is stopped, while an air-close valve opens completely under the same conditions. It seems to be said the opposite way.
Hehe, it was the last sentence that hit the mark, that’s why I gave a rating. A gas-on valve: it opens when there is gas, and closes when there is no gas. It is also called FC, Failure Close. The same is true in reverse.
A gas-on valve opens when there is gas and closes when there is no gas. A pneumatic shut-off valve closes when there is air pressure and opens when there is no air pressure.
Air release valve: FC – Closes in the event of a power outage. It requires compressed air to open, and the valve closes when the air supply is cut off. Air shut-off valve: FO – Opens in the event of a power outage. Compressed air is required to close it; the valve opens when the air supply is cut off. Last edited by 3300 on 2007-12-6 12:24]
This is instrument air, used to control the opening and closing of instruments. Air-operated valves are opened using compressed air, while air-operated shut-off valves are closed using compressed air.
A gas-on valve opens when there is gas and closes when there is no gas. A pneumatic shut-off valve closes when there is air pressure and opens when there is no air pressure. Selection between gas-on and gas-off mode: It is necessary to consider what will happen when there is no gas available. If there is a sudden loss of pressure, the valve that opens will close, and the valve that closes will open. Consider the intended use and choose the safer one. For example, if you want to fill a tank with water, if the outlet valve is closed, the water will overflow; therefore, it’s necessary to open the valve when there is no air present, that is, when the air valve is closed. The inlet valve should be selected to open when there is air present.
Air supply valve – the valve for supplying air is opened； FC is a gas-on valve; gas-off valve – the valve that closes when gas is supplied ； FO is a gas-shut valve and a gas-open valve; the choice between them is determined by the safety requirements when the gas supply is interrupted.
You say they got it wrong, but actually it’s you who’s mistaken. A gas-on valve: it opens when there is gas, and closes when there is no gas. A pneumatic shut-off valve closes when there is air pressure and opens when there is no air pressure. \"Gas\" refers to instrument air (control air).
Air opening valve: The valve opens when there is an air supply; it closes when the air supply is lost. It becomes an FC valve. Air shut-off valve: The valve closes when there is air supply, and it opens when the air supply is lost. Become an FO valve. Determining whether a valve is air-open or air-close depends on its safety status. If the valve being in the open position represents a safe condition, then it must be a air-operated shut-off valve. The same is true in reverse.
Thank you. The day I parked the car, I checked the status of the valves used for adjustment
A gas control valve opens when there is gas present and closes when there is no gas； The air shut-off valve is the exact opposite. Choose between air-open and air-close based on the safety status of the valve
A gas-on valve opens when there is gas and closes when there is no gas. A pneumatic shut-off valve closes when there is air pressure and opens when there is no air pressure.
A gas-controlled valve is one that can be closed only when there is gas present; it opens automatically when there is no gas
A wind-operated valve is one that can be opened only under the action of instrument air when the process is operating normally; in other words, instrument air is necessary to keep it in the open position. If there is a failure and the instrument air supply is interrupted, the valve will then be in the closed position. Therefore, a wind-operated valve is also known as a fault-closed valve, denoted as FC (fault close). A wind-controlled valve, on the other hand, is one that can be closed only under the action of instrument air during normal operation; instrument air is required to maintain it in the closed position. In the event of a failure and the loss of instrument air supply, the valve will switch to the open position. Hence, a wind-controlled valve is also called a fault-open valve, denoted as FO (fault open)