pneumatic vs electro-pneumatic valves 1

[mae1133]

Having a debate with colleagues whether there is a difference between these two types of pneumatic actuated valves. Can't find a clear definition which would explain the difference, but don't all pneumatic valves have electric solenoids (AC or DC) to control the air flow to the valves cylinder or diaphragm housing (or a positioner if its a modulating valve)? The solenoids require electricity to open or close, so does that not make the whole assembly electro-pneumatic valves (we just refer to them as pneumatic actuated valves or pneumatic valves)? Or is there such thing aa a fully pneumatic valve without requiring electricity of some form to control a solenoid or positioner?

 

[goutam_freelance]

Purely pneumatic CVs have pneumatic positioner (without electrical intervention). Electro-pneumatic valve will receive position signal from an electronic control system or positioner and final control element is pneumatic. It is similar to purely hydraulic vs electro-hydraulic control valves(as normally used for steam/gas turbines).

Engineers, think what we have done to the environment !

https://www.linkedin.com/in/goutam-das-59743b30/

 

[TugboatEng]

There are valves that are operated entirely by air. They are typically called pilot operated valves.

 

[Chandramouli Attili]

i feel definition of pneumatic or electro-pneumatic valves were some what old. As already few experts here expressed, pneumatic valve operates only by means of compressed air and the entire control is done by means of mechanical linkages. An electro-pneumatic valve involves solenoids, motors or any other electrically operated devices to operate the valve and control the valve. However, in present days one can not imagine a pure pneumatic valve to put in any kind of industry, be it cement, chemical, food, manufacturing or any other. Even a presence of solenoid valve in the valve assembly should be treated as electo-pneumatic or electro-hydraulic valve. With this definition, the valve hence forth attracts several other regulations and certifications in addition to mechanical safety. Hope this is helpful!