valve actuator selection criteria

[masoudinst]

dear experts

A junior colleague asked me about valve actuator selection criteria and i am trying to support her with a reasonable answer.She asked me what are the key criteria to select different types of actuator for process valves although she and me deemed in most occasions spring return pneumatic actuators are the best and most reliable solutions.But still we are not sure about criteria to use pneumatic cylinder and hydrolic acutaro as well as different type of them like scach yoke and rack and penion and also different types of hydrolic actuators.

any clues would be appreciated.

 

[danw2]

Check out this recent debate/commentary thread on pneumatic vs electric actuators

http://www.eng-tips.com/viewthread.cfm?qid=323523

 

[bcd]

Your subject is too broad for a single reply. There are many different types of actuators because there are needs for many different types. The best choice depends upon your needs. What power source is readily available? Compressed air, hydraulic, electric, etc. What type of valve are you operating? on-off or control? Linear or rotary stem movement? Operating environment and temperature range? How fast does the valve need to move? How many cycles does the actuator need to last? How much space do you have around the valve to fit an actuator? What is the fail-safe position of the actuator, as-is, fail open, or fail closed?

As you can see, the best type depends upon what you need the actuator to do. Then you can get into who manufacturers the best of that type.

 

[lacajun]

My experience reflects bcd's post. It always depends on what you're trying to do so it varies from application to application.

Pamela K. Quillin, P.E.
Quillin Engineering, LLC