Fluid MechanicsFull Glossary

Kv (Flow Factor)

European equivalent of Cv. Defined as the flow in m3/h of water at 5–40 degrees C with 1 bar pressure drop. Conversion: Cv = 1.156 x Kv, or Kv = 0.865 x Cv. Used in EN/DIN valve specifications and European process plants.

Related Terms

Control ValveCvPressure Drop

Frequently Asked Questions

What is Kv (Flow Factor) in the context of industrial valves?

European equivalent of Cv. Defined as the flow in m3/h of water at 5–40 degrees C with 1 bar pressure drop. Conversion: Cv = 1.156 x Kv, or Kv = 0.865 x Cv. Used in EN/DIN valve specifications and European process plants.

How does Kv (Flow Factor) affect valve selection and sizing?

European equivalent of Cv. Valve sizing must account for this phenomenon to prevent premature failure, excess noise, and vibration. For control valves, ISA-75.01 and IEC 60534-2-1 cover sizing for incompressible and compressible flow. Vajra Industrial Solutions can assist with valve sizing calculations - contact sales@vajravyuh.com with your process data sheet.

What valve types minimise Kv (Flow Factor) problems?

The choice of valve type and trim significantly affects susceptibility to flow-related problems. Anti-cavitation trims, low-noise cages, multi-stage pressure reduction, and proper Cv sizing reduce velocity-related damage. For critical applications, control valve sizing is performed using the ISA/IEC methodology with FL (liquid pressure recovery factor) and Fd (valve style modifier) for the specific valve geometry.

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