How large or small is the line?
Is this for on/off or throttling?
Pneumatic force is normally used within the process industry to move the valve and an electrical signal is used to throttle or switch the pneumatic medium such as an instrument air supply. Solenoid valves can switch the air for on/off applications. For small valves, perhaps less than one-inch, solenoids operate the valve directly. Hydraulic fluid is used for very large forces. Electical motor operated and self-contained electro-hydraulic actuators can control valves where no air supply exists.
Fisher (look for Emerson Process/Fisher-Rosemount, etc.) is among the leaders with good stuff such as a "Control Valve Handbook" on the web.
Maybe try contacting an electronic actuator manufacturer (e.g. Rotork, EIM) to see what sizes of actuator they have that would be suitable for your valve.
If you could figure out how to use a 24Vdc 3-way, 2-position solenoid valve for compressed air or inert gasses from 28" Hg vacuum to 125 psig pressure, here's a bargain I noticed a few days ago: <allelectronics.com> CAT# SV-4
A valve is a piece of metal, plastic, other material, that is in a pipe/line, and provides a "restriction" to flow.
When people say electric valve, it is usuall taken to mean an electric actuator on a valve. An electric actuator uses electricity to move/stroke a valve.
An alternative is to use a pneumatic actuator. In which case, air (or N2, fuel gas, etc.) is used to move/stroke the valve instead of electricity.
Seems like every time I walk up to a package boiler it is festooned with Maxon valves. I have no affiliation or specific experience with these guys, but installed base speaks to their success.
