Valve selection
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I would like to ask about how to choose a pneumatic diaphragm control valve: should it have a sleeve, a cage design, cut-off functionality, or a pilot system? What are the criteria for making such a choice?
My feeling is to choose based on the actual pressure difference before and after, as well as the maximum cut-off pressure difference. The general pressure difference for pilot types is relatively small, while it is somewhat larger for sleeve and cage types. I’m not sure if what I said is correct, haha. You can ask the engineers for advice
Cut-off function of control valves is rarely used; single-seat valves can achieve cut-off, while cage-type valves are quite good if they can achieve leakage levels of 4 or 5
It depends on the medium, as well as the pressure difference before and after the valve. The flow capacity of sleeve and cage types is not good; it seems they can resist flashing and similar phenomena.
This post was last edited by gratcn on 2016-9-21 14:04: Is there a shut-off function for the control valve? Isn’t this contradictory?
Study* study!* ! ! ! ! ! ! ! ! ! !
You can take a look at the information on control valves
It’s the type with a valve core that includes a seal, resulting in an extremely low leakage rate
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Control valves cannot be used for shut-off purposes; since they are control valves, they have specified leakage values, and as long as the leakage does not exceed the **standard allowable leakage value, it is acceptable