Flow control of centrifugal pumps
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To design a small system that requires control over the mass flow rate of a centrifugal pump, should the flow meter and control valve be installed in the inlet pipe or the outlet pipe of the pump? Thank you
It seems you’re a beginner – the flow control valve cannot be installed at the inlet; the flow meter and control valve must both be installed at the outlet!
The flow control of centrifugal pumps is generally achieved by controlling the outlet valve; when controlling the inlet valve, cavitation can easily occur if the inlet flow is reduced too much.
Flow control is installed at the pump outlet, and there are two common control methods: 1) flow meter + regulator + control valve; in this case, a circulation loop is usually required at the pump outlet, 2) flow meter + regulator + variable frequency drive, which is a more energy-efficient method. However, all designs determine the optimal control scheme based on the actual operating conditions on site.
Since it is a centrifugal pump, the control valve must be installed at the pump outlet, followed by a flow meter; make sure to provide adequate straight sections before and after it. If it is a reciprocating pump, the control valve must be installed in front of the pump.
Based on the characteristics of the pump, reciprocating pumps can only have control valves installed in front of them; they cannot have such valves behind them.