Flow & Pressure Control

Yes.

tell me about it

It depends entirely on your application.
In the 'staying alive' application, the human lung and repiratory tract work together to control both, even when there is quite severe lung damage.
But one could argue that it's two devices, and I'd say that is generally true, a pump/blower/fan to generate pressure and some sort of baffle/restrictor/valve to control flow.
Del

Much is dependent on what your wanting to do. How many CFM, PSI etc are you wanting to control. 1/4" - 4" line? Manufactures for various products are Numatics, SMC, Parker, list goes on and on. Look on Global Spec and you should be able to find what you need if you know the above answers.

You can put an upper limit on both pressure and flow, or (with a variable load) you can keep the pressure constant while the flow varies, or keep the flow constant while the pressure varies (both of these up to the limit of your input air supply.

But (with a variable load), you can't keep both the flow and pressure constant. Think about it.

I would direct you to a forum I posted recently discussing mass flow controllers. Pressure control is better done independently.

http://cr4.globalspec.com/thread/59039/High-Precision-Flow-Meter

Yes. Please intimate inlet upstream pressure psi, downstream pressure psi and air flow required cfm min & maximum.