Problems related to the use of valves in liquefied gases
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Three-piece ball valves are installed in the liquid CO2 pipelines to control flow on and off. Liquid CO2 flows inside the valve ball; when the valve ball rotates 90 degrees to close, the liquid gas inside it gets sealed within the valve body (valve casing), between the two sealing gaskets. If the valve is not used for an extended period of time, the liquid inside may vaporize, resulting in high pressure that can damage the seals, especially those around the valve stem； I would like to ask how everyone handles this situation? If the valve is open, this issue can be ignored, as small holes are drilled in the connecting keyway between the valve ball and the rotating rod; even if high pressure is generated inside, it will flow into the pipeline through these holes, so it won’t cause any problems
If it’s just for controlling on/off, consider a butterfly valve!
I have never used a butterfly valve; is its sealing performance sufficient for use with gases or gas-liquid mixtures?
In many of the situations I’m talking about, ball valves are being used; I’m not sure how those valves can function properly
Look at how much pressure you’re under! Generally, it’s no problem if it’s under 16 kilograms
I’m not sure whether you provide the operating conditions accurately when purchasing valves. For ball valves installed on pipes under high pressure, two small relief valves are designed in the middle chamber ； Alternatively, specify the medium flow direction for the ball valve; the ball and the upstream end are equipped with connection holes to ensure pressure balance.
Is a pressure relief valve installed in the middle chamber to automatically release pressure when it gets high?
Set the pressure relief value for the pressure relief valve according to your operating conditions; it will automatically release pressure when the pressure in the inner chamber exceeds this set value.