Thursday, September 24, 2015

Why Do We Debate Air vs. Electric Powered Valve Actuators?

Rotork Industrial Valve
Industrial Process Control Valve
Courtesy Rotork
Which is better, air or electric? We're talking about valve actuators here. Just for perspective on how original this article might turn out to be, I commanded my friendly Google search engine to look for "air vs. electric actuators". Google always finds something, no matter what you ask, giving the humble user an impression that the big "G" has all the answers....and they truly may. Don't misunderstand me. I am a big Google fan. Someday I might even pay for something that they provide me. Anyway, I was humbled by the avalanche of search returns on my the subject, 17,200,000 articles. That's a large number, even for a Google search. Many of the articles related to industrial machinery automation, not valves. Changing my search to "electric vs pneumatic valve actuator" shaved the returns down to 236K, a more manageable volume.
Dutifully reading the highest ranked articles and following threads in forums, I started to wonder why, like figurative gladiators, we pit these two valve actuator motive power sources against one another. There is not a single winner in this case. One is not universally better, more advantageous, than the other. Both methodologies have instances where they can be used to best advantage. A good recommendation is to not be too influenced by the past, by what your own industrial process control experience may have been. The manufacturers of these products are continuously modifying designs and releasing products with newer technologies and better performance that may eliminate some shortcomings of the past.

Your best course of action is to consider the following:

  • What is the expected useful life of the process? Short term, long term, permanent?
  • Will existing air supply and piping system accommodate the anticipated additional pneumatic valve load, if that type actuator seems otherwise advantageous?
  • Are there sufficient maintenance and technical resources in place to keep either system in top operating condition and successfully deal with operational and repair issues that will arise? Does the current maintenance staff have sufficient knowledge and training to perform needed tasks?
  • Are there rated hazardous zones where valves will be located?
  • What needs to happen to valve position if motive power (air pressure or electricity) fails?
  • What valve positioning requirements are associated with proper control of the process?
  • What interfaces with any existing control systems, if any, need to be accomplished?
Carefully consider these points, add several of you own. Consult with knowledgeable sales engineers that specialize in valve automation. Combine experience and knowledge from a number of sources and a good solution will materialize.