Selection of air-closed and air-open control valves
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Please tell me the selectivity of the air-closing valve and the air-opening valve of the regulating valve you have used. Where are air valves used? Where to use air shut-off valve? Tell me why this type of valve is used? What factors have been considered?
The selection of air-to-open and air-to-close valves is mainly based on safety considerations. If you want the valve to be open in an accident state (such as power outage, water, etc.), select the air-off valve (FO), otherwise select the air-open valve (FC).
I am engaged in the oil refining industry. I think the choice of air valves and air duct valves is mainly based on safety and process needs. Generally, in order to avoid pumping out, the hydraulic control valve needs to keep the regulating valve closed when the air is stopped. Generally, the flow control valve is selected to remain open when the air is stopped. Generally, in order to avoid holding back pressure, the pressure control valve needs to keep the regulating valve open when the air is stopped. This is generally the case. Special treatment should be given to special cases and cannot be generalized.
As mentioned on the 2nd floor, opening of Qi means closing of accident, and closing of Qi means opening of accident. Mainly from the perspective of production safety. For example, for the anti-surge valves of the low-pressure cylinder and high-pressure cylinder of ice machines, in the event of an accident, it is hoped that the valves will be open to prevent surge caused by low inlet flow, so the accident-open or air-close valves are used.
The selection of air-to-open and air-to-close valves is mainly based on safety considerations. Generally, air is used to open the valve for liquid level adjustment, and air is used to close the valve for the gas phase. This kind of regulating valve uses instrument air as the air source. When the instrument air is interrupted, the air opening valve is fully closed and the air closing valve is fully opened to ensure the liquid level of the equipment and prevent high pressure from flowing into low pressure, causing accidents.
That's very good. Let me talk about the ammonia synthesis tower position. We are a fully cold-shock ammonia synthesis tower. 1. The cold-shock gas regulating valve is a gas-opening valve, because when the gas source is cut off, the valve will automatically close. If an air-closing valve is used, the air source will be fully opened, and the sudden increase in air conditioning will overwhelm the temperature of the catalyst layer. 2. The drain valve is an air-opening valve. In this way, when the air source is cut off and the valve is closed, it will not cause high pressure and low pressure, and avoid explosion. At the same time, the bypass valve can be opened, so that the synthesis tower will not carry liquid. 3. The waste boiler water adding valve is a gas-closing valve, which will not cause the waste boiler to dry out. 4. The shortcut of the system is a gas-closing valve to prevent the tower temperature from being overwhelmed. At this time, the cold quench gas can be used to adjust the tower temperature and the circulation machine to adjust the tower temperature.