Electric actuated valves are essential components in industrial automation systems. They are used to control the flow of fluids, gases, or other materials through pipelines by using an electric motor to operate the valve mechanism. These valves are a crucial part of modern industrial processes, where precision, reliability, and efficiency are paramount. In this article, we will explore what electric actuated valves are, how they work, their different types, advantages, and the applications where they are most beneficial.

 

Understanding Electric Actuated Valves

An electric actuated valve is a valve that uses an electric actuator to open or close the valve, controlling the flow of materials in a system. The electric actuator typically consists of an electric motor, gear mechanism, and position feedback system. The actuator is powered by electricity, and it moves the valve to a desired position, either fully open or fully closed, or anywhere in between.

Electric actuated valves are commonly used in automated control systems to ensure precise regulation of fluids in processes where consistency and safety are crucial. These valves eliminate the need for manual operation, allowing for faster, more efficient, and often safer control of processes.

 

Working Principle of Electric Actuated Valves

How Electric Actuators Drive Valve Movement

Electric actuators use electrical energy to generate mechanical motion, primarily in the form of rotational or linear movement, depending on the valve’s design. The core of an electric actuator is the electric motor, which converts electricity into mechanical energy. For rotary valves, such as ball or butterfly valves, the motor’s rotational movement is transferred via a gearbox to the valve stem, providing the necessary torque to open or close the valve. For linear valves, the motor typically drives a lead screw or similar mechanism to move the valve plug or gate. The precision of electric actuators ensures that valves can be adjusted with high accuracy and control, enabling automated operations in industrial systems.

Torque and Power Requirements

The torque output of an electric actuator is crucial for ensuring that the valve operates properly. Torque is the rotational force required to turn the valve’s stem and open or close the valve. Electric actuators are designed to deliver a specified amount of torque, which must match the torque requirement of the valve. This is particularly important in large valves or high-pressure systems where significant force is required to initiate movement. Power requirements depend on factors like the valve size, fluid type, and system pressure. Actuators come in various sizes and power ratings, with some designed to handle higher torque and others optimized for faster, more precise movements. The actuator’s motor and gear system work in tandem to achieve the necessary power for proper valve operation​.

Manual Override and Limit Switches

In cases of electrical failure or the need for manual intervention, many electric actuators include a manual override feature. This allows operators to manually adjust the valve by using a handwheel or other mechanism, bypassing the electric motor temporarily. Limit switches are also incorporated into the actuator system to define the range of motion. These switches automatically stop the actuator at predetermined positions, preventing over-rotation or under-rotation of the valve. Limit switches can either be mechanical or electronic, and they are essential for ensuring that the valve operates within its intended range, preventing mechanical damage and ensuring safe, precise control over the valve’s position​.

 

Types of Electric Actuators

There are two main types of electric actuators commonly used in industrial settings:

Linear Electric Actuators

Linear electric actuators convert electrical energy into linear motion, facilitating push or pull actions. They typically consist of an electric motor connected to a screw mechanism, such as a ball screw or lead screw, which translates rotational motion into linear displacement. This design enables precise control over position and speed, making them ideal for applications like valve operation, material handling, and robotics. Linear actuators are valued for their accuracy and repeatability, essential in processes requiring exact positioning.

Rotary Electric Actuators

source:Autorun

Rotary electric actuators convert electrical energy into rotational motion. They comprise an electric motor coupled with gear systems to achieve the desired torque and rotational speed. These actuators are commonly used in applications requiring angular movement, such as operating valves, dampers, or other rotary mechanisms. They offer precise control over angular positioning, speed, and torque, making them suitable for tasks like indexing, positioning, and controlling rotary valves.

 

Components and Features of Electric Actuators

Position Indicators and Feedback Control

Electric actuators often feature position indicators and feedback control systems to provide real-time monitoring of the valve’s position. These components are essential for ensuring precise valve operation, as they help relay the actuator’s current position to a control system. Feedback control mechanisms can include sensors such as potentiometers or encoders, which send information about the actuator’s position back to a central control system. This allows operators to monitor valve status remotely and make adjustments if necessary. In critical applications, this feedback is crucial for maintaining safety and performance, as it ensures the valve reaches its intended position accurately and consistently.

Duty Cycle and Fail-Safe Features

Electric actuators are often designed with specific duty cycle ratings that define how long they can operate before needing a rest period to avoid overheating. For instance, typical electric actuators may have a duty cycle of 25%, meaning they can operate for 25% of the time and require cooling during the remaining 75% to prevent damage. In safety-critical applications, the actuator may be equipped with fail-safe features such as battery backup systems or spring-loaded mechanisms to ensure the valve moves to a default position (usually closed) during a power failure. This ensures that the actuator and the valve it controls can still function in emergencies, such as in industrial or process settings where valve operation is vital to controlling fluid flow or preventing damage.

Modulation Capabilities

Electric actuators can provide highly precise modulation control, which is important in systems where gradual, continuous adjustment of the valve is necessary. These actuators are often used in applications where the valve’s position must be varied incrementally to control fluid flow, pressure, or temperature. Modulating control can be achieved using various feedback mechanisms, such as 4-20mA signals or advanced controllers that continuously adjust the actuator’s speed and position. This allows for accurate regulation of parameters in automated systems and makes electric actuators suitable for both on/off and proportional control applications, offering versatility and fine control.

Remote Operation and Control

One of the major advantages of electric actuators is their ability to be operated remotely, which is particularly beneficial in hazardous environments or locations that are difficult to access. Electric actuators can be integrated into a larger automation or control system, allowing operators to control the valve’s operation from a safe distance. This remote control capability can include simple on/off switches or more complex systems that provide continuous monitoring and adjustments through a centralized control panel. Communication protocols such as HART, Modbus, or Profibus are commonly used to integrate electric actuators into industrial networks, providing enhanced flexibility and operational efficiency in controlling valve positions across large, automated systems.

 

Advantages of Electric Actuators

Electric actuators offer numerous advantages in industrial applications, particularly in terms of precision, reliability, and integration capabilities.

High Precision and Control in Fluid Flow

Electric actuators provide exceptional precision in controlling fluid flow, enabling accurate positioning and movement. This high level of control is essential in processes requiring exact adjustments, such as in chemical dosing or fluid mixing. The ability to fine-tune operations enhances efficiency and product quality.

Reliability and Durability

Designed for longevity, electric actuators exhibit high reliability and durability. Their robust construction minimizes the need for frequent maintenance, reducing downtime and operational costs. This reliability is crucial in critical applications where consistent performance is mandatory.

Integration with Control Systems for Automation

Electric actuators seamlessly integrate with modern control systems, facilitating advanced automation. They can be easily networked and reprogrammed, offering immediate feedback for diagnostics and maintenance. This compatibility allows for streamlined operations and real-time monitoring, enhancing overall system responsiveness and flexibility.

 

Applications of Electric Actuated Valve

Electric actuated valves are used in a wide range of industries where precise control over fluid flow is needed. Common applications include:

Oil and Gas: Electric actuated valves are used to control the flow of oil, gas, and other fluids in pipelines, refineries, and offshore platforms. Their reliability and ability to operate in hazardous conditions make them ideal for these applications.

Water Treatment: In water treatment plants, electric actuators help regulate the flow of water and chemicals, ensuring the accurate treatment of water for consumption.

Food and Beverage: These valves are used to control the flow of liquids in food processing plants, maintaining strict hygiene and regulatory standards while ensuring efficient production.

Chemical Manufacturing: In chemical plants, electric actuators are used to control the flow of hazardous chemicals, gases, and other substances, with precision and safety being top priorities.

HVAC Systems: In heating, ventilation, and air conditioning systems, electric actuators regulate airflow and temperature, ensuring optimal energy efficiency and comfort.

 

Selecting the Right Electric Actuated Valve

When selecting an electric actuated valve, several factors need to be considered:

Factors to Consider

• Torque Requirements: Ensure the actuator provides sufficient torque to operate the valve under all conditions, including breakaway torque needed to initiate movement. Inadequate torque can lead to operational failures.
• Voltage Compatibility: Match the actuator’s voltage requirements (e.g., DC24V, AC110V, AC220V, AC380V) with your power supply to ensure efficient operation.
• Mounting Connections: Verify that the actuator’s mounting interface is compatible with the valve, adhering to standards like ISO 5211, to facilitate proper installation and alignment.

IP Ratings and Enclosure Protection

• Ingress Protection (IP) Ratings: Assess the actuator’s IP rating to determine its resistance to dust and water ingress. For instance, an IP67 rating indicates protection against dust and temporary immersion in water, suitable for harsh environments.
• Environmental Considerations: Consider factors such as exposure to chemicals, humidity, and temperature extremes. Selecting actuators with appropriate enclosure protection ensures durability and reliable performance in specific operating conditions.

Application-Specific Considerations

• Operational Environment: Evaluate the specific conditions where the valve will operate, including temperature ranges, pressure levels, and the nature of the fluid (e.g., corrosive, abrasive).
• Control Requirements: Determine whether the application requires simple on/off control or precise modulation. This will influence the choice between actuators designed for binary operation versus those capable of fine adjustments.
• Safety and Compliance: Ensure the actuator meets relevant industry standards and certifications, especially for applications in hazardous areas, to maintain safety and regulatory compliance.

 

Maintenance and Troubleshooting of Electric Actuators

Routine Maintenance Requirements

• Visual Inspections: Regularly examine external surfaces, control knobs, and valve stems for signs of wear or damage. Ensure that paint finishes are intact to prevent corrosion.
• Lubrication Checks: Monitor and replenish oil levels as necessary to maintain smooth operation of moving parts.
• Fastener Integrity: Inspect mounting bolts, nuts, washers, and screws for tightness and signs of corrosion or damage.
• Manual Operation Verification: Test the manual handwheel to confirm it operates correctly and that there is physical movement of the valve.
• Electrical Connections: Remove terminal covers to check for tightness and inspect compartments for moisture ingress. Replace ‘O’ ring seals as needed to maintain enclosure integrity.

Common Issues and How to Address Them

• Brake System Malfunctions: Improper brake adjustments can lead to operational inefficiencies. Ensure the brake lining maintains a high friction coefficient and that lubricants do not compromise braking performance.
• Output Lag: Misalignment between the actuator’s output shaft and the valve can cause delays. Verify that the actuator output angle matches the valve body angle, and ensure correct correlation of feedback signals.
• Sensitivity Settings: Incorrect servo amplifier sensitivity can affect response speed and stability. Adjust sensitivity settings to achieve desired performance levels.
• Vibration Interference: External vibrations can disrupt actuator function. Install actuators away from vibration sources and secure them on sturdy foundations to minimize interference.
• Feedback Signal Errors: Inaccurate feedback can lead to positioning errors. Regularly calibrate feedback systems and ensure the error margin between the feedback signal and actual valve position remains within acceptable limits.

 

Electric vs Pneumatic Actuators Chart

Aspect	Electric Actuators	Pneumatic Actuators
Power Source and Operation	Convert electrical energy into mechanical motion, offering precise positioning control.	Utilize compressed air for movement, providing rapid response times.
Control and Precision	Excel in high-accuracy applications; finely tunable for specific positions.	Responsive but less precise due to air compressibility; suited for on/off control.
Maintenance and Environment	Require less maintenance; operate quietly but sensitive to temperature and moisture.	Robust in harsh conditions but need regular air system upkeep to avoid leaks and contamination.

 

Solenoid-Actuated vs Electric Actuators Chart

Aspect	Electric Actuators	Pneumatic Actuators
Power Source and Operation	Convert electrical energy into mechanical motion, offering precise positioning control.	Utilize compressed air for movement, providing rapid response times.
Control and Precision	Excel in high-accuracy applications; finely tunable for specific positions.	Responsive but less precise due to air compressibility; suited for on/off control.
Maintenance and Environment	Require less maintenance; operate quietly but sensitive to temperature and moisture.	Robust in harsh conditions but need regular air system upkeep to avoid leaks and contamination.

 

Conclusion

Electric actuated valves are a critical technology for modern industrial automation, offering precise, reliable, and energy-efficient solutions for controlling fluid flow. By understanding how they work, their types, and their advantages, you can make more informed decisions when selecting electric actuators for your systems. Whether you’re working in oil and gas, chemical processing, or water treatment, the benefits of electric actuators—such as improved precision, lower maintenance, and seamless automation integration—make them an excellent choice for a wide range of applications.

When choosing an electric actuated valve, it is important to consider factors such as torque, power requirements, and environmental conditions to ensure you select the best option for your specific needs. Tanggong Valve Group offers industry-leading electric actuated valves tailored to your needs—contact us today to find the perfect solution for your application!