When you have a question about process automation that needs a short answer, let us know with #WishIknew and @Visaya! We’ll reply with a #WishIknew post. It’ll give a quick explanation, then some related articles, videos, or reviews if you want to know more.

I wish I knew What parts do control valves have?

Back in the day, I used to say that control valves exist in a different universe from the usual instrumentation, and you need to live in that world to know how to handle them. You can learn a ton in school, but some details you’ll learn only when you work with them.

Okay, let’s talk control valves and their parts, which break down into three parts.  The valve itself means the actuator and the body. Those units break down into smaller mechanical pieces to make everything work properly. They also have gaskets here and there to prevent leakage.

The third relevant part of a valve assembly is the positioner. This unit receives a signal from the control system if the product level doesn’t match spec. In a pneumatic valve, it sends air to move the valve according to the system’s request.

control valves
Courtesy of ISA

A control valves actuator can be pneumatic, electric, and hydraulic. The valve bodies can have different types as well, such as globe, ball, butterfly, diaphragm, and gate. And control valves can have other variations, such as different flow characteristics, quick openings, or liners. And that covers most control valve assemblies in a nutshell!

This video will tell you more about valves in general:

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