Thinning problem of control valves
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Hello everyone. I would like to ask that, according to SH/T 3005, in item 10.1.4.3g), the diameter of the control valve shall not be larger than that of the pipeline. In order to reduce stress in the pipeline, the maximum reduction in diameter of the control valve shall not exceed two stages, and it shall also not be less than half of the pipeline’s diameter； According to the regulations, if the process pipeline is 20 inches in diameter, what is the minimum diameter for the control valve? I see some 10-inch options on site; do they still meet this standard? “How should the “maximum diameter reduction of the control valve” be understood? Thank you for the reply and discussion.
1) Select the diameter of the control valve based on the physical properties and parameters of the fluid； 2) Then connect the corresponding piping. Generally, the valve diameter is smaller than the pipe diameter, with the two connected by reducers. As for smaller calibers, it’s not necessarily the case ； I am engaged in valve research and technical support; please add me on WeChat at 924549064
This diameter reduction indeed cannot exceed two stages. For example, if your process pipeline is 20 inches in diameter, the diameter of the control valve should be at least 16 inches; 18 inches represents one stage, while 16 inches also represents one stage. Of course, this is a single diameter change; it’s also possible to achieve a transition from 20 inches to 10 inches by making multiple diameter changes along the same pipe, but this requires increasing the length of the pipe between the two diameter changes in order to meet the requirements.