“Is the method of \"increasing the open degree of the control valve to extend its service life\" also applicable to diagonal-stroke control valves or gate control valves?
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What I’ve seen is that the control valve should operate at its maximum opening degree from the start, such as 90%. In this way, damages such as cavitation and erosion occur on the head of the valve core. As the valve core is damaged, the flow rate increases, so the valve closes a little more.” However, the sealing surfaces of the valve core in control gate valves and V-ball control valves are different from those in globe valves; it’s not clear whether the same principle applies here as well
It makes no sense to operate at 90% opening! As a result, the valve has poor adjustability. The ideal valve opening is around 50%; for valves with equal characteristics, it can be a bit lower.
If the control valve is set to 90% opening, then what is the purpose of using a control valve at all? Above 60-80, the control valve no longer offers much in terms of adjustability
Theoretically, all of them are applicable, but the optimal range for the opening degree of the control valve should be between 20% and 85%
What you’re talking about is just a state of dealing with things based on past experience, right? Vapor erosion in valves can be addressed through the design of the valve’s internal structure and by applying hardening treatments; for example, if the flowing medium causes vaporization or erosion, sleeves or cages can be used to eliminate such issues, and the sealing surfaces can be hardened as well. If, as you said, the opening is first set to a large value and then adjusted to a smaller value based on the cavitation erosion situation using empirical methods, then the leakage rate of the valve will definitely be very high. I’ve never heard of a regulating gate valve; gate valves are usually used for shutting off flow, not for regulation. The V-ball can be adjusted.