Valve leakage class
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There is a on/off valve with a leakage rating of level 4; how can it be upgraded to level 5?
The leakage level of the valve is determined by the valve manufacturer in accordance with the requirements of Party A; in such cases, it is usually necessary to replace the valve or even change the valve manufacturer.
Please let the original poster specify what type of control valve it is (ball/disk/gate?) ), metal or soft seal? @jiaguoyun
Follow the pressure testing standards; the standards specify the allowable leakage amount
You can test to find out what the actual leakage level of this valve is. Some valves actually meet the V-grade standard, but the requirement is for a IV-grade standard; therefore, they are specified as such at the time of production. Valves with smaller diameters generally manage to reach the V-grade standard.
It is sufficient to re-grind the valve core and seat; for grades IV to V, normal grinding is enough, unlike grade VI!
Is the requirement too high? Is there still too much leakage?