The difference between an electric actuator for regulated valves and an electric actuator for on/off valves
As an important Actuator in the industrial automation control system, the electric actuator can be controlled centrally from a long distance to meet the needs of computer program control. Quarter-turn Electric Actuators are used to control 0°~270° rotation valves and other similar products, such as butterfly valves, ball valves, dampers, baffle valves, plug valves, louver valves, etc., which can be widely used in petroleum, chemical, water treatment, shipbuilding, papermaking, power station, heating, light industry and other industries. It uses 380V/220V/110V AC power supply as the driving power supply, and 4-20mA current signal or 0-10V DC voltage signal as the control signal, which can make the valve move to the desired position and realize its automatic control, with a maximum output torque of 4000N·m.
When selecting the Electric Ball Valve actuator, in addition to paying attention to the compatibility with the valve and other components, it is also necessary to consider the control mode of the valve electric actuator. In terms of control modes, there are two common types of valve electric actuators: on-off valve electric actuators and regulating valve electric actuators, and their differences need to be understood in detail.
1. Regulating valve electric actuator
Regulating valve electric actuator is also called closed-loop valve electric actuator, this valve electric actuator not only has the control function of valve switch, but also can control the opening amount of the valve to achieve the control of the medium flow. In terms of working form, regulating valve electric actuators are divided into electric opening valve electric actuators and electric closing valve electric actuators. For example, the regulating electric actuator of VTON is used for Electric Butterfly Valve and electric ball valve, which uses 380V/220V/110V AC power supply as the driving power supply, and 4-20mA current signal or 0-10V DC voltage signal as the control signal, which can make the valve move to the required position and realize its automatic control, with a maximum output torque of 4000N·m.
The working control signal of the electric actuator of the electric opening valve and the electric actuator of the electric closed valve is different, and the working form of the electric actuator of the valve should be determined when selecting the model, otherwise it is not suitable in the control system and is difficult to modify.
When the actuator is unable to accept the signal due to line failure or other reasons, it will open and close the Control Valve by itself, usually the valve is fully open, fully closed or kept in place.
2. On-off valve electric actuator:
Switch-type valve electric actuator is also known as open-loop Control Valve electric actuator, this actuator only has two actions when performing valve operation, opening and closing, that is, it can only make the valve fully open or fully closed. Switch-type valve electric actuators cannot control the amplitude of the valve switch, and therefore cannot control the flow of the medium. There are two types of electric actuator construction methods: split structure and integrated structure.
The on/off valve electric actuator of split structure must be equipped with a control unit to complete the control operation, so it is not convenient for the overall installation of the system, and the investment cost is large, the failure rate is high, and it is not conducive to diagnosis and maintenance.
The integrated valve electric actuator is a combination of the control unit and the electric actuator into one structure, and there is no need to match the control unit to complete the operation of the valve. The integrated valve electric actuator supports remote control, as long as the control information is output to the valve electric actuator, it can complete the operation task by itself.
3. The difference between on-off valve electric actuator and regulating valve electric actuator
The difference between on-off electric valves and regulating electric valves is that on-off electric valves are only used for the medium on the pipeline, usually fully open or fully closed. On the other hand, the regulating electric valve can be used not only for switching, but also for adjusting (4~20mA or 0-10V) signal input and output. Therefore, when selecting imported electric actuators for valves, we must pay attention to whether the on-site use requirements are switch type or regulation type.
