Control Valve · Glossary

What is Installed Characteristic?

flow vs travel in the real systemControl Valve

Installed characteristic is the actual relationship between valve travel and flow once the valve is in its piping system.

Installed Characteristic Explained

In a real system the valve pressure drop changes with flow, because pipe and equipment losses rise as flow increases. This distorts the inherent characteristic.

With low valve authority a linear valve behaves like quick opening, while an equal percentage valve becomes close to linear.

Calculators for Installed Characteristic

CalculatorInstalled Valve CharacteristicFree online calculator with formula and worked example.CalculatorValve Authority CalculatorFree online calculator with formula and worked example.

Free Downloads

Free downloadControl Valve Sizing Excel SheetFree download in Excel and PDF.

Frequently Asked Questions

What is Installed Characteristic?

Installed characteristic is the actual relationship between valve travel and flow once the valve is in its piping system.

Why does the installed characteristic matter?

Loop gain depends on it. A strongly curved installed characteristic makes the loop sluggish at one end and oscillatory at the other.

How do I find it?

Calculate flow at several openings using the system curve, or test the loop at different loads.

Learn more on the blog

Control valve flow coefficient (Cv and Kv)

A practical guide on instrumentationblog.in with more detail on installed characteristic and how it is applied on real plants.

Read Full Article

More Control Valve Terms

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