Actuators put a new face on process-control problems

Aug. 8, 2002
Copar rotary actuators provide pneumatic control of ball, butterfly, and throttle valves.

Copar rotary actuators provide pneumatic control of ball, butterfly, and throttle valves.

The challenges of modern process automation are, in a sense, rather basic. Opening, closing, and adjusting valves that control flows and mixing ratios continue to form the foundation of successful industrial, municipal, and laboratory process-control applications.

Pneumatic technology has proven to be an ideal solution in process applications, due to its inherent safety, simplicity, and cost efficiency.

One example is in explosive environments where safety or cost issues prohibit electric motor-driven actuators. Other process-control applications where pneumatics excels include water and sewage treatment and transportation, treatment plants for ultrapure and industrial water, desalination, reverse osmosis, and ion-exchange operations.

Festo, Hauppauge, N.Y., produces a range of process actuators. Its Copar unit, a quarter-turn rotary actuator, is available in single and double-acting designs. Both can directly open and close ball, butterfly, and throttle valves, as well as stop at intermediate positions using closed-loop positioning technology. Pneumatic cylinders drive rack-and-pinion units to rotate the actuator shaft. The actuators are available in 14 sizes with torque ranging from 8 to 8,000 N-m at 6 bar. Maximum operating pressure is 10 bar.

The company's Copac linear pneumatic actuators control gate valves, flat valves, and weirs. They are available in six bore sizes ranging from 80 to 320 mm, with noncontact end-position sensing as a standard option. The double-acting actuators have stroke lengths between 40 and 2,000 mm and produce between 2,800 and 47,500 N of force at 6 bar.

An optional, integrated measuring system positions the actuator anywhere within the stroke range, for precise control of gate valves or weirs. A sturdy housing protects it from damage in harsh environments while maintaining a compact package size.

The Copar and Copac actuators are rated for temperatures between –20 and 80°C, and maximum operating pressure is 10 bar. They operate on lubricated or nonlubricated air, are corrosion resistant, and mount in virtually any orientation. For more information, visit

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