There are many types of dampers and blade orientations. Regardless, control dampers are used to control air flow in a process and require a modulating actuator to manipulate flow.
When it comes to control performance however, the damper performance is only as good as the performance of the damper actuator. It is a well-documented fact that many industrial control loops function poorly as a result of actuation problems. Common applications where this can occur include louvers, butterflies, and radial inlet vanes on ID fans, FD fans, primary air, windboxes, overfire air, coal mills, and many other control dampers. Unfortunately, the harsh environment where these dampers reside often makes it difficult to keep them operating freely. Actuators ideally suited for this environment should provide better control and reliability, and lower the cost attributed to overall operation.
When selecting a damper actuator, the actuator should have performance characteristics that will enable a control system to perform as designed.
The key damper performance characteristics are as follows:
- Precise, repeatable positioning typically better than 0.15% of span.
- The ability to start and stop instantaneously without dead time or position overshoot.
- Continuous duty rating without limitations on the number of starts per minute.
- Perform consistently and unaffected by load.
- Rugged industrial design capable of operating in difficult environments without an effect on performance.
- Minimal periodic maintenance required.
A damper actuator designed with these characteristics provides two extremely important advantages:
- An ability to follow the demand signal from the controller precisely and instantly. This ensures that the actuator responds exactly as directed by the controller. Thus, the actuator is not the limiting factor in the control loop and the controller can function to its optimal levels.
- A high degree of maintenance-free reliability. An actuator designed to function as outlined above by default is more rugged than typical actuators. By design, then, it is capable of a much higher degree of reliability.
Beck electric actuators provide the necessary control and reliability that is required for many damper applications. The Group 11 actuator product line is often found on low to medium torque applications (20 lb-ft to 5,200 lb-ft). Group 22 actuators are utilized for high torque applications (3,000 lb-ft to 8,000 lb-ft), and Group 31 compact rotary actuators are utilized on low torque applications (15 lb-ft to 30 lb-ft).
Investments in control systems and field instrumentation are only as useful as the performance of the final control element actuators allow. Installing damper actuators designed for the rigors of continuous modulating process control is the key to optimal control and sustainable improvements.