What is the relationship between a self-acting control valve and reference gas?
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Dear experts, may I ask what is the purpose of introducing reference air in a self-acting control valve?
That’s an interesting question; I’ve never seen it before. My analysis is: the opening degree of the self-regulating valve is controlled based on the pressure of the reference gas, so that the pressure of the controlled medium remains constant at the level of the reference gas pressure.
I also thought it was regulated by reference gas, but it seems not to be the case, as self-acting control valves are not regulated by reference gas themselves; I’m a bit confused
Is there no shut-off valve between the self-pressurized medium entering the diaphragm head and the reference gas entering the diaphragm head?
What does this have to do with it? There is no self-acting type; the reference gas is connected directly to the valve. What is the use of the reference gas?
This is sampling: the pressure on the side before or after the control valve is adjusted, and a sample is taken from that side. Once the sampled pressure reaches the set value, the self-acting control valve remains in a stable state. When manufacturing valves, the adjustment range of the self-acting control valve is designed based on the range you need to adjust.