Am currently doing an investigative analysis to find out where I can save more with regards to valves. im choosing whether to use electric actuated valves or pnuematic actuated valves

Which is more cost effective and why?

 

You'll have to clarify a few things first about you intended installation for me-

Do you need to get an indication signal back to a PLC or SCADA system?

You don't say if they are to be straight simple open-closed valves or "controlled".

How long would the run be if cable was used?

Are they in a "hazardous" area?

 

Red:
If you have some communication going with the local reps in the area, they will probably hand you a multitude of documentation.
Undoubtly, some filtering will be in order?
Some questions.
Do you have a variety of valve types and sizes?
Size is a major impact?
Safety considerations for the same is pertinent as well.
Another factor relative to size and type. What reaction time is necessary for the final control element?
Which valves are open and closes versus throttling?
Torque and speed for opening and closing of the valve will direct your thinking for motor operator or pneumatic actuator.

Some typicals:
Air actuation can handle higher torque and reaction is faster.
Air quality is an important issue, as well as all the ancilliary equipment to provide the air.
The motor operator eliminates the air ancilliary equipment necessary.
Some look at the whole air compressor, dryer, filtration, capacity and so forth as a major headache.
With the motor operator, consider the control concept of the valve, if for no other reason than the backlash issues with the mechanism.
Just some brief thoughts.
Good luck.
Regards,
Paul Dackermann

 

I beleive that for simple control tasks electrical actuated control valves are more cost effective as you will be saving energy at the air compressors.

 

If these are emergency shutdown valves, you might want to also consider gas over oil (hydraulic) The control logic can also be important in the application whether you are using electric, hydraulic or pneumatic. If the valve is critical, make sure you have good shut off systems/logic.

Your best bet would be to talk to someone who has had previous experience problems with valves. A peer of mine had a problem (for example) when his refinery caught on fire and burnt through the electric actuator cables. All the electric actuators failed to close during the fire and more fuel got burnt up. I am not saying that you should not use electric actuators. I am just saying that there are considerations that need to be met.

 

Regarding electric vs. pneumatic actuators. You need to provide additional information specific to your application. Fail-Safe electric actuators will eliminate the issue that took place at the refinery.

As a manufacturer of 1/4 turn electric actuators, Valvcon can provide network capable product, actuators that are NEMA 4,4x,7&9, fail-safe, modulating, etc. Pneumatic will provide quicker cycling times then electric. Is air close by? will the size of your project force the need for additional compressors? Visit us at http://www.valvcon.com.