Can a three-eccentric butterfly shut-off valve regulate flow? What is the maximum pressure difference it can handle?
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Can a three-eccentric butterfly shut-off valve regulate flow? What is the maximum pressure difference it can handle? Our plant has a cut-off valve designed for emergency shutdown, which is a triple-eccentric butterfly valve. Recently, the manual valve located ahead of it has been leaking severely, and it’s not possible to stop production for repairs. We are considering using this triple-eccentric butterfly valve as a manual alternative, with the flow rate controlled via an on-site handwheel. I’m not sure if this will work; the pressure before the valve is 50 bar and the fluid is in liquid form, while the pressure after the valve is 5 bar, meaning there is a pressure reduction. I wonder whether this butterfly valve can withstand such a pressure difference If it’s possible to carry this out practically, what should be taken into consideration? :)
A valve positioner should allow for flow regulation; it is generally used for shut-off valves.
Based on the situation described by the poster, it’s possible.
This post was last edited by lyqing1980 on 2017-2-15 at 14:58. Using a triple-eccentric positioning device as a control valve is a well-established approach; however, it is suitable only for rough adjustment and not for precise control applications. The maximum pressure that a butterfly valve can handle is 10 Mpa
It depends on the design pressure of the butterfly valve itself, as well as whether it is a hard-sealed butterfly valve; since soft-sealed valves cannot withstand erosion under such operating conditions； The triple-eccentric hard-sealed butterfly valve is designed with a regulating function, but its precision is not high.
This can be adjusted, but precise adjustment is not possible; the damage caused by flash vapor erosion and cavitation to the valve must also be taken into account
The triple eccentricity can be adjusted roughly, and since this is for emergency use, there’s no problem
It’s absolutely not allowed; it cannot be controlled at all, and voltage crossover between the high-voltage and low-voltage systems can lead to accidents.
How did you relieve stress before? With a hand valve? From 5MPA to 5 kilograms? Will it work?
I haven’t tried it. The manufacturer says it’s possible, but we don’t dare to give it a try either; it’s the final safeguard. If something goes wrong and high voltage leaks into the low voltage side, everything will be ruined!