Old Valves, New Tricks

Whether by Adding Intelligence and Networking or by Refining Traditional Hardware, Actuators and Positioners Continue to Gain New Capabilities to Help Their Users Operate More Efficiently and Reliably

Old dogs may be uncooperative, but you can teach old valves to sit up and roll over. In fact, for technologies that are 80 years old and sometimes older, there’s a lot going on with valves and the actuators and positioners that move and control them.

Sure, everyone knows how valves evolved from manual and motorized actuation, then to relay-based and integral controls, and onward to today’s microprocessor-based, non-intrusive, controls that can perform remote data processing and communicate via field bus, Ethernet and even wireless. But that’s not the end of the story. Traditional valves, actuator and positioner technologies still are being updated and improved, and many versions are more affordable now, so they can be used in smaller applications. And, as field bus-enabled and microprocessor-based valve technologies have gained traction, they too have evolved new capabilities.

Perhaps because many valve, actuator and positioner technologies have been used for decades, they’re often accompanied by some equally persistent problems and technical limits. For example, the fact that air and other gases are inherently compressible means it’s been difficult to control valves using traditional pneumatics. This is mainly because the data signals from these systems also fluctuate, and so it’s hard for their controls and operators to respond as quickly or efficiently as desired or required. Sometimes added pressure is needed to overcome valve stiction, but that pressure may also cause some valves to open too far or close too tightly. Also, compressed air is costly to produce, and its components are subject to leaks. These factors and normal wear can lead directly to inaccurate valve performance, which indirectly reduces end-product quality in many applications.

Electric actuators and positioners have promised more precise control, but these newer methods are limited by the simple fact that they can’t operate without power. So developers have been faced with how to make electrically driven valve components fail-safe.

With an old actuator, a lot of air leaks and over-use of air is a common problem, and so companies are faced with upgrading whole compression systems. With the new B-Torq actuators and complete system packages from BDK, companies no longer have air bleeds, and in certain cases may have excess air capacity without having to upgrade air systems.

Traditional spool-valve positioners will give a response in seconds, but smart positioners can respond in milliseconds, which greatly improves performance. Our actuator is almost precise for all applications, and this is two to four times better than the ±1.0% accuracy that actuators used to have, which means less dead band or slop. This is important because distributed control systems (DCSs) and other control systems are more sophisticated, and so end users must keep installed devices up to the DCS’ new capabilities.

Formulate a game plan for efficiently managed systems in your organization, by answering the following questions:-

• What and where are your critical control loops?

• Which are the critical control valves in those loops?

• Where do you need alerts and alarms and how should you set them up?

• Have you prioritized your loops and their alerts?

• Where are you communicating alerts to?

• Once an alert is received, such as performance is off or a failure is approaching, what’s the next step in your work process and practice?

Remember :- Better Data = Better Performance

To improve your systems you need a reliable partner, speak to a BDK office located near you and see what our actuators and valves can do for you.