Some clients often ask us what is the difference between the control valve and the on-off valve, today we would make a very comprehensive introduction about their difference.
The on/off valve is XV for short, the control valve is usually CV for short, it can also be LV, FV, PV for short
The on/off valve is fully opening or closing valves in the pipeline, it can isolate a fluid totally and provide tight shut-off. Usually, it is used in TSO and ESD conditions, pump discharge, etc. For example, in the processing pipeline, such as cooling water lines, a motorized on/off valve can be applied to allow fully open or stop the fluid flow.
The control valve is to control and regulate the flow according to the process condition, its shut off capabilities is not as good as the on/off valve.
The on/off valve body can be a ball valve, butterfly valve, gate valve, plug valve, or globe control valve. They are often equipped with solenoid valve and cut off accessories, like a limit switch, pressure regulator, and filter.
The control valve is a globe type body with position response and it is assembled with an accurate positioning device.
Differential Installation point
The on/off valve is usually installed at upstream of the control valve, and it is installed in open-loop control.
The control valve is installed downstream of the on/off valve, it is installed in closed-loop control.
Differential open level
The on/off valve should be 100% open or closed.
The control valve open degree depends on the process condition requirement, for example, the tank needs a 30% level, the control valve is installed at the bottom of the tank in the pump discharge. If the tank level increases over 30%, the level control of the tank will open the control valve in the pump discharge to keep the level in the tank.
Differential type of control
The on/off valve only control the flow of fluid
The control valve can regulate and modulate any type of control, such as pressure control, flow control, temperature control, and level control
Differences in precision
Differences on response
The control valve is more faster and accurate for opening or close action.
The on/off valve response is slower than the control valve
The difference between the control element
Control valve: have an analog control element
On/Off valve: a digital control element or manual