Electric actuators are one of the essential parts of modern control systems. They range from small, compact units used for domestic and business purposes to large, heavy-duty units for industrial applications. Electric actuators can provide you with the accuracy and efficiency you want in controlling the flow of solids, gases, or fluids. This blog gives you all the information you need about how an electric actuator works, including answers to the question, “How does” an electric actuator work valve?”

Basics of Electric Valve Actuators

Electric valve actuators open and close valves. Ball and butterfly valves move in straight lines or circles. Specific process control systems use instructions to help govern electric valve devices. Instructions determine what actions the actuators have to execute. The regulation of far- or wide-scattered systems becomes easy when electric valve actuators are used.

A central system governs electric motors while forwarding scheduled instructions to them. This simplifies operations and enhances the system’s reliability for organizations. These actuators respond faster, use advanced technology, and are simple to operate.

Essential Components of an Electric Actuator Valve System

Electric Motor:

The actuatoractuator’sntal components are electric motors, which produce the mechanical force (rotational or linear motion) required to operate the valves. The following are the possible types:

• AC motor is suitable for heavy-duty applications that necessitate consistent performance.
• DCmotors are frequently employed in low-power or compact applications.
• Servo motors are used in advanced actuators

Gearbox:

The gearbox converts the high-speed, low-torque motor output into the low-speed, high-torque motion necessary to activate the valve, transferring the motion from the motor to the valve.

Mechanism for Feedback:

The feedback mechanism relies heavily on sensors to observe the valve’s motion. It checks whether the valve is proper by comparing the actuator’s position with the control signal it has and supplies the results as an instantaneous update to the control unit.

Torque and Thrust Sensors:

The sensor monitors the applied rotational force or linear force, referred to as thrust. This allows for modification in the movement of the actuator so that there is no overburden or damage to valve and actuator components.

Monitoring the continuous operation of these sensors would require the critical factor of the duty cycle. It measures the duration an actuator can operate at maximum capacity before necessitating a cooling-down period.

Control Unit:

The actuator control system or device controls the actuator motor to push the valve to its desired position in response to processing the input signal. It works as the actuatoractuator’sIn some more complex setups, the control unit can have connections to PLCs. PLCs permit the control of several actuators at the same time, enable the execution of more complex functions, and can connect the actuator system with other parts of the plant in order to obtain smooth overall control.

Manual Override Mechanism:

This is a secondary control method that enables the actuator to be operated manually in the case of malfunctioning (i.e., poor symptoms in the actuator) or lack of automated control. Thus, operations can be maintained in the event of a failure in the computerized system.

Fail-Safe Mechanism

A safety feature is designed to automatically return the system to a safe state in case of a failure, such as a loss of power or a failure of one of the components.

Battery backup systems automatically power the actuator during power outages, and spring return mechanisms will position the valve in its default or safety position by shoving it wide open or to a completely shut position.

Electric Actuator Valve Working Principle

A modern automated system has to have an electric actuator valve. Electric valves are used more precisely and efficiently to control fluid or gas flow through pipelines or any process. This operation changes electrical energy to mechanical motion, which allows the valve to be placed exactly at different stages after a signal of control is sent.

• Power Supply

The electric actuator valve is operated through an external power supply, typically 24V DC or 110V AC. This power supply is necessary to drive the internal motor that controls the valve. Electric actuators convert electrical energy into mechanical motion to regulate the valve. They are often integrated into automated systems requiring constant energy input for proper function. Backup power, often a battery, will ensure a continuous supply during a blackout. For that reason, uninterrupted power is usually required to maintain the actuator’s viability and keep accurate valve regulation. Loss of positioning of valves might occur upon losing power in operation; however, the stable provision of power allows an efficient function of the actuator with the rated parameters in its operations.

• Signal Reception

Signal reception is one of the significant steps for operating an electric actuator valve. Typically, control signals are received from a central control system or local switches. Signals can be analog types, such as 4-20 mA, or digital (such as Modbus and BACnet) as a system is designed. These are interpreted as commands by the actuator that sends the commands for the valve’s valves. It regulates fluid flow, pressure, or temperature through a signal from the control system to adjust the position of the valve. This real-time signal reception allows the actuator to correspond to system requirements, enabling accurate adjustment. Communication between the actuator and the control system ensures correct processing and interpretation of signals.

• Signal Processing

This step mainly receives signals for control from a central control system or local switches. The actuator should understand the actuator should understand the input command for actuating the movement of the valve. Control will signal to alter valve position regarding changing fluid flow or pressure. Even with changes in the pressure, flow rates, and temperature, it could interpret and correspond to the position desired to receive the signal correctly. Correct communication processing can ensure signal input between the actuator and control using established protocols.

Motor Activation

The motor activation in an electric actuator valve is done after the signal has been processed. After receiving and processing the control signal, the motor opens or closes the valve. Electric motors are usually DC or stepper motors. These motors create the torque necessary for the motor to rotate. The rotation of the motor converts the electrical signal into mechanical movement, which opens or closes the valve. The motor’s power and speed depend on the type of actuator and design specifications. Activation is very accurate and provides reasonable control over the movement of valves, thereby maintaining the accurate flow. Stepper motors are widely used in cases where precision is critical, whereas DC motors are applied for general applications. The feedback received from the control system guides the motor to ensure that the valve does not overshoot in its position.

• Valve Positioning

When the motor is activated, the actuator moves the valve to the appropriate position based on the received signal. Position feedback mechanisms, such as potentiometers or encoders, monitor the advancement of the actuator. These sensors generate real-time data within the control system, meaning the valve is always in the right position. The actuator constantly controls its motor speed or torque to match the signal from the sensors. When it has reached its target position, the actuator stops and continues to hold this set position. Valve positioning plays a significant role in regulating many processes in various systems, be it pressure, temperature, or fluid flow. Inaccurate positioning leads to under or over-regulation in such systems, producing inefficiencies and damaging some.

• End Limit Detection

Electric actuators integrate limit switches or sensors in their systems that sense the valve’s valves. Such sensors are developed to indicate whether the actuator has hit the mechanical limit of the valve on the open side or closed side. At the detection of the end limit, the actuator will stop motioning so that no over-travel damage will occur. It thus eliminates the need to worry about its valve getting any undue wear due to its inappropriate time for movement cessation. Some physical limit switches use actuators wherein engaging is facilitated upon reaching the end of an actuator shaft.

• Power Cutoff

Power cutoff is among the most critical functions of electric actuator valves to maintain safe operation. This would disconnect the power supply once the actuator has reached its intended position. It would stop the actuator from constantly drawing any power to prevent energy waste and overheating. Power cutoff prevents overheating. Continuous supply to the motor can cause it to overheat. This safety feature can be combined within the controller or a separate actuator relay. On receiving this feedback that the valve has moved to the intended position, it cuts the power supply, ensuring no movement. 

• Continuous Monitoring

This step involves constantly checking the actuator’s motor condition and system status during operation. Feedback sensors track the movement and position of the valve, sending real-time data to the control system. Continuous monitoring also detects anomalies or issues, such as motor overheating or feedback discrepancies. When irregularities are detected, the system can take corrective action, such as adjusting the motor and triggering an alarm.

This feature enhances the actuator’s reliability by ensuring that potential issues are addressed before they cause system failures. In some advanced actuator systems, continuous monitoring is integrated into more extensive predictive maintenance programs, helping to prevent unexpected downtime.

• Safety Mechanisms

Overload protection prevents the motor supplied with an overload actuator from taking in excessive amperage due to current, thus minimizing the risk of motor burnout. In a malfunction, fault detection systems alert operators or automatically close the actuator. Emergency stop functions enable operators to halt the movement of the actuator in emergency stop situations to ensure personnel safety.

Some actuators are also fitted with manual overrides and operate manually in case of a power or system failure. Some designs also include mechanical fail-safes, like spring return mechanisms, which automatically reset the valve to its default position in an emergency.