Control valves incompressible flow

For any control valve design be sure to use one of the modem methods, such as that given here, that takes into account such things as control valve pressure recovery factors and gas transition to incompressible flow at critical pressure drop. 

Sizing of control valves is important because, if the valve is oversized or undersized, accurate control of the flow rate can be poor and a contrain for the flow rate can be contrained. A simplified valve flow equation for an incompressible fluid is given by... 

Control valves in the line will clearly have a major effect, and ways of calculating this effect for both compressible and incompressible flow will be given in Chapter 7. 

Never install two control valves in series in a single liquid-filled line because liquids are essentially incompressible and flow through the hne should be determined by one... 

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