A flow control valve, abbreviated as FCV, controls the flow of a process stream. This might be in the form of an automatic shutdown valve or it might installed downstream of a centrifugal pump. A flow control valve on the discharge of a pump holds back pressure on the pump, which in turn forces the pump to operate at a specific rate.
To size a flow control valve, the user must know the upstream pressure, required downstream pressure (or differential pressure), and range of flow rates. Ideally, a control valve should operate at 75% of its normal travel.
A flow control valve modulates across a range of flows and the pressure drop across the valve is characterized by the type of trim that is installed.