Electric valve actuators are employed to control the valve openings in various industrial processes. The actuator’s purpose is to convert electrical current into mechanical energy. But how exactly does an electric valve actuator work? Let’s take a look!
Electric valve actuators typically use an electric motor, which can be either AC or DC, to convert electrical energy into rotary or linear movement. The motor is connected to the valve stem via a mechanical transmission link, such as a gearbox, belt, chain, or direct drive linkage. This transmission link converts the rotary or linear movement of the motor into linear or rotary motion at the valve stem.
When the electric valve is energized, the motor drives the transmission link and the valve stem moves the valve plug or disc to open or close the valve. The amount of movement is typically limited by a mechanical stop or by the open / close limit switches in the electric actuator. The position of the valve stem relative to the valve opening can often be monitored by a position transducer such as a potentiometer, encoder, or other sensors.
Electric valve actuators can be stand-alone unit with an integral motor and transmission link combination, or they can be modular, where the motor and transmission are separate components linked together. Modular actuators are typically adjustable in their speed, torque and stroke, making them a versatile and flexible option.
Motor types used in electric valve actuators include synchronous and asynchronous motors. Synchronous motors are more expensive, but are smaller and lighter than asynchronous types and provide accurate positioning and steady operation. Asynchronous motors are more rugged and less expensive than synchronous types, but are typically noisier and less accurate.
Electric valve actuators offer a wide range of control options to adjust torque, speed and stroke as needed. They can be operated remotely via a handheld remote or a PLC, and can also be tied into SCADA systems for automated operation. Sophisticated systems can include self-tuning feedback loops to adjust the performance of the unit for optimal operation and efficiency.
Electric actuators are the workhorses of the industrial process control field, providing reliable and efficient operation. When selecting an electric actuator for any of your automated process needs, it is important to select one that is tailored to match the process conditions and requirements, such as media, temperature, flow rate and pressure. The electric valve actuator must also be designed to meet any additional requirements, such as safety feature or other environmental conditions.
To sum up, electric valve actuators convert electrical energy into linear or rotary movement to control valve openings. This is accomplished by connecting an electric motor to the valve stem, either directly or through a mechanical transmission element. Electric actuators offer a wide range of control options, such as adjustable speed, torque and stroke. In addition, they can be integrated with a variety of control systems such as SCADA and PLCs. Lastly, when selecting an electric actuator it is important to select one that is well suited to the process conditions and requirements, as well as any additional safety or environmental conditions that may be required.
