How to choose the diameter of a control valve?
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The design institute provides a data sheet for control valves, and then the manufacturer selects a specific model based on that sheet. For example, if the original pipe diameter is DN100, the manufacturer might choose a valve with a diameter of DN40. This represents a significant reduction in diameter; according to standard 20507, the diameter of control valves should not be reduced as much as this. How should one communicate with the manufacturer to ask them to select a different model, or should they go with the valve suggested by the manufacturer?
Come and discuss your solutions.
This post was last edited by hfrs on 2017-12-26 at 15:59. If it’s a path coefficient, it cannot be less than half. Without specific data tables, it is impossible to calculate. Besides, the path analysis calculations should be provided by the design institute – didn’t your design institute provide them?
First, the manufacturer should provide a calculation sheet; once you have it, compare it with the calculation sheet prepared by the design institute. Check whether the values such as the calculated CV and opening degree from the design institute differ significantly from those provided by the manufacturer. The difference is too large; it’s likely that one of the parties made a mistake in the calculations. Then look at the rated CV selection; different manufacturers have different rated CV values. If the manufacturer has large-diameter models with the same rated CV, simply communicate with them to have it replaced. If not, report the situation to the design institute; consider changing the model, or there may be issues with the data provided by the manufacturing process, so have the design institute verify it again. Finally, if the process conditions are correct and it’s not possible to find a valve that meets the requirements, there is no alternative but to use a valve with a diameter smaller than half of the pipe diameter.
In this case, you can only bring it up to check whether there are any issues on the part of the design institute and the manufacturer; if indeed there are no problems, there’s no need to stick strictly to the regulations.
The size of the valve provided by the manufacturer must be confirmed by us before it can be installed and used; I’m not sure what you mean
Do you mean by changing the model later that having the manufacturer select a new model based on the data sheet?