Internal leakage in the shut-off valve
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The exhaust valve started leaking within half a year of use, with only a slight leakage. Upon inspection, the valve appeared to be in good condition and there were no scratches on its surface. It is a hard-sealed, wear-resistant ball valve operating at a temperature of 180 degrees and under a pressure of 5 kilograms. What could be the cause of this?
What is the leakage rating of a hard-sealed ball valve? How is microleakage detected? The temperature here isn’t too high either; PTFE soft-sealed valves will work just fine
The required leakage level is VI; the process is unstable as there are sometimes small particles present, and an odor is detected after the valves are closed during maintenance
Can a hard-sealed ball valve achieve VI? At such a high level?
What brand of valves? Could you send over the nameplate?
There are still many type 6 hard-sealed ball valves. The visual inspection is good; the gasket and preload can be considered.
Hard-sealed ball valves can achieve a VI level of leakage resistance; for domestic products, it is necessary to grind the valve ball against the valve seat, while manufacturers with advanced technology abroad are said to be able to carry out standardized production (allowing for arbitrary combinations). Such minor leaks are likely to go unnoticed just by visual inspection, so it might be a good idea to start by checking the valve seat system. If it is necessary to determine the source of the problem, a leak test can be performed.
Okay, let’s check more carefully – the valve is too large to undergo a leak test
With such a high sealing rating and no scratches, it’s unlikely to be a leak. Could it be that the actuator takes too long to operate, resulting in a leakage smell during the valve closing process?
Is there a problem with the actuator? Is it possible to fully close it to the off position? Check the tightening bolts of the ball valve to see if they are loose; tighten them