Ball valve leakage rating
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I would like to ask fellow sailors: can the leakage resistance level of domestic ball valves with hard seals reach grade 6?
Few places can achieve it; generally, it’s level 5. Only a few companies in China are capable of reaching level 6
This post was last edited by Baihui Ch set on 2010-6-26 at 20:43. Currently, most companies claim to be able to achieve this standard verbally; in reality, it is not possible in China to maintain a VI level of performance with hard-sealed designs for extended periods of time. After all, metal surfaces come into contact with each other, and due to the varying operating conditions of different users, the sealing efficiency varies as well. During testing, it is possible to reach level VI; virtually all manufacturers are able to do this. However, after a few months it no longer works. The testing methods and standards for V VI are also different; pressure and diameter need to be taken into account. Just as the standard for domestic zero-leak butterfly valves purchased by petrochemical giants will also be achieved in the short term.
The claim by manufacturers that control valve butterfly valves (with two or three eccentricities) have a hard seal up to grade 6 is mostly exaggerated; in actual testing, it is very rare for such levels of sealing to be achieved. Even if new valves pass the inspection initially, they stop functioning after being in use for some time, and maintaining them is complicated and requires sophisticated hardware. Therefore, I suggest that for large-diameter butterfly valves, too much emphasis should not be placed on their cutting capability, as their primary function should be regulation.
That level 6 can still be achieved when new products come out
I wonder which standard specifies this?