Seeking help with a question regarding how globe valves regulate flow and pressure
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Two operating conditions: 1. The discharge pressure of the pump is high; the pressure is reduced by adjusting the globe valve after the pump. What impact does this have on the flow rate? Does the flow rate decrease as well? 2. The pump has a high flow rate; the flow rate can be reduced by adjusting the globe valve after the pump. What effect does this have on the pressure? Does the pressure also decrease? What is the relationship between pressure and flow rate as a result of adjusting the globe valve? Thank you! Sometimes I want to regulate pressure, and other times I want to regulate flow; I’m not sure when to use a globe valve.
What the poster is referring to is probably a centrifugal pump; positive-displacement pumps cannot have their flow rate adjusted using an outlet valve. During design, the outlet flow rate is generally controlled, while the pressure is determined by the subsequent system. When the outlet flow rate is too high, reducing the outlet valve will naturally lower the flow rate. As for pressure, it will increase slightly before the valve due to throttling (on the pump’s curve, as the flow rate decreases, the head increases); after throttling by the valve, the pressure remains roughly the same as before throttling.
Is it a centrifugal pump, or a variable-frequency pump?； The required head is now much lower than before, and the flow rate does not change significantly ； The current approach is to achieve this by reducing the frequency, which results in particularly low efficiency at that time.
In simple terms, regular valves are used to regulate pressure, while control valves are used to regulate flow. . . Most control valves use globe valves as their valve body. . .
A globe valve is a general term for a type of valve body; most water supply control valves are of this type, as they can be used to regulate both flow rate and pressure, and one such control valve solves the problem