pressure control valve

[qeqe]

I want know any kind of usual pressure control valve and information about those in detail whith figure and control circuit.if anyone have information about those item please described to me as bellow step
step1:how does it work in detail with airset,actouator,positioner
step2:how does it controlles the pressure
step3:figure and control circut whith describtion.
Thank you very much
email:sh_khoshmanesh2002@yahoo.com

 

[ChasBean1]

Here's an example:

http://www.thermal-solution.com/Dungs/Pressure_Regulators/FRG/FRG_SD.htm

There's not a functional description in this diagram, but if you look at it, it's pretty simple. Outlet pressure drops, it's sensed as reduced force under the diaphragm - spring pushes stem down, opening reverse seated valve. Pressure rises and exceeds spring force, re-seating valve.

-CB