Why Electric Actuators Matter in Modern Process Plants
Electric actuators convert electrical energy into controlled rotary or linear motion. Compared to hydraulic actuators or pneumatic devices powered by compressed air, electric actuators can reduce energy use, maintenance, and contamination risks. This makes them beneficial in food and beverage, chemical, and pharmaceutical-adjacent processes.
Strahman Group brings decades of experience with industrial process valves and valve automation. Through BI-TORQ Valve Automation, Strahman offers electric actuators and complete valve packages for demanding industrial applications.
Advantages:
- Precise control and repeatable positioning
- Clean, quiet operation
- Reliable PLC and DCS integration
Fundamentals of Electric Actuators and Linear Motion
An electric actuator uses an AC or DC motor to create rotary motion. A gearbox manages the speed and torque, while internal controls direct the actuator to the necessary position. In a quarter-turn design, the output drive transfers that rotational motion to the valve stem, rotating it 90 degrees between open and closed positions.
Some common components include the motor, gearbox, housing, bearings and feedback devices. Limit switches define the fully open and fully closed positions, while thermal overload protection protects the motor during a stall condition. Depending on the configuration, positioners, feedback transmitters and torque sensors can add more control and operating data.
Rotary actuators produce rotational motion around an axis, and linear actuators deliver a straight push or pull. A rotary electric actuator therefore matches their required movement without adding a separate linear-motion mechanism.
BI-TORQ electric actuators also use permanently lubricated, heavy-duty gearing, reducing routine lubrication while helping the actuator withstand demanding industrial service.
Main Types of Electric Actuators by Motion: Rotary, Multi-Turn, Quarter-Turn, and Linear
The four main types of electric actuators are classified by motion: continuous rotary, multi-turn, quarter-turn, and linear motion.
Rotary actuators offer continuous or limited rotational motion around a fixed axis. Rotary electric actuators with feedback provide precise angular displacement.
Multi-turn actuators rotate through several revolutions, often five to 20 turns or even more. They operate rising-stem gate and globe valves, where the stem threads convert rotation into linear motion.
Quarter-turn actuators move 90 degrees, although some designs offer up to 180 degrees. Their response time and compact size are good for ball, butterfly and plug valves.
Linear actuators create push-and-pull movement for valve stems, louvers, diverter gates and positioning slides.
For the valve types offered in BI-TORQ’s automated packages, quarter-turn actuation provides the best mechanical match. Quarter-turn actuators are the smart choice when the valve itself is designed for around 90-degree rotational motion.
Electric vs. Hydraulic and Pneumatic Actuators: Pros, Cons, and Use Cases
Electric, hydraulic, and pneumatic devices are the three most common actuator categories.
Hydraulic actuators rely on pressurized fluid, often at several thousand psi. Some designs can even generate 15,000 lbf or more. Typical types are single-acting, double-acting, telescopic, and rotary hydraulic actuators. While they provide high force for presses and large gates, leaks, fluid service, and contamination can still lead to problems.
Pneumatic actuators use compressed air. They respond quickly and have lower component costs, making them common for quarter-turn ball and butterfly valves. Pneumatic actuators typically offer less positioning accuracy than electric models, and compressors and air leaks also add on to energy costs.
Electric actuators offer precise control, programmability, and easy digital integration. Some electromechanical designs reach 75% to 80% efficiency, although actual performance can vary. Self-locking linear actuators can hold loads without drawing power.
Key distinctions:
- Force: hydraulic systems deliver the highest force density
- Speed: pneumatic systems suit rapid on/off movement
- Precision: electric systems provide accurate positioning
- Maintenance: electric systems eliminate fluid and air service
- Cleanliness: electric systems fit sanitary production
How to Choose the Right Electric Actuator for Valves and Process Equipment
Refer to this checklist when comparing electric actuator types:
- Load and torque: Calculate thrust or torque from valve size, media, differential pressure, and seat friction. Apply a reasonable safety factor without oversizing enough to damage the valve.
- Motion: Determine whether the application demands linear or rotary motion. Ball and butterfly valves usually require quarter-turn rotary actuators, while gate and globe valves use multi-turn units or linear actuators.
- Speed and stroke: Define travel distance and opening or closing time. These affect motor size, gearing and screw selection.
- Duty cycle: Record cycles per hour and peak operating periods. Frequent cycling favors ball screw linear actuators over lead screw models.
- Environment: Review ambient temperature, washdown frequency, chemicals, steam, and hazardous-area classifications. Compare the IP ratings, seals, and stainless-steel options.
- Space: Check the complete operating envelope; parallel electric actuators use spur gears, right-angle models are quieter, and in-line units fit narrower spaces. Electric sliding actuators allow movement without an outer tube.
- Control: Choose between simple open/close operation or modulating service with analog or digital feedback.
BI-TORQ can integrate actuation packages with ball valves, butterfly valves, and specialty valve assemblies.
BI-TORQ’s Perspective: Electric Actuators in Valve Automation Solutions
Electric actuators can complement BI-TORQ’s valve automation solutions and thermal shut-off safety valves, as well as Strahman’s process valves. The best applications include food and beverage sanitation, chemical-process modulation, and safety-oriented packages for high-temperature or fire-safe service.
Strahman Group’s ISO 9001:2015-certified manufacturing facility promotes consistent production. All packages are engineered with precision and made for performance, with long service life and ownership cost prioritized.
Our coordinated approach gives engineers a tested assembly with components selected properly for the process.
Contact Strahman Group about a custom valve automation package today.