Newbie seeking help
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In a triple-eccentric hard-sealed butterfly valve without any mechanical stop mechanism, at a pressure of around 30 kilograms in the pipeline, will the sealing surface of the valve disc close completely? Thank you to the seniors for helping to clarify my doubts.
I don’t think so. By the time it is closed, the butterfly valve is already perpendicular to the pipeline, and the forces are in balance.
The sealing performance of butterfly valves is among the worst among various types of valves. However, with advances in technology, the sealing performance of 3-eccentric valves has improved significantly, though it is still inferior to that of ball valves and similar valves； Using a butterfly valve under a pressure of 30 kilograms is no problem – it can provide a good seal. However, it is essential to use a composite sealing system that combines hard sealing with soft sealing for the sealing surfaces, and it is better to choose manufacturers with experience; smaller factories may not be able to do this properly
Thank you. It’s originally a pneumatic model with a manual controller; at the site, the limits for both the manual controller and the cylinder were set to their extreme positions, which meant that the limits no longer functioned. So I was worried that the valve plate might close too far. I think a triple-eccentric design shouldn’t pose too many problems, but I’m still concerned.
Excessive closing can cause damage to the eccentric sealing surface; it is recommended to slowly adjust it back to a satisfactory closing position before resetting the limit.
The triple-eccentric butterfly valve, without limit plates or driving mechanisms, will not close beyond its limit during the closing process, as the sealing surface is perpendicular to the centerline of the valve stem. It will only get tighter the more it’s restricted.