Technical Article · Ar-Ge Ekibi
How to calculate the Kv value when selecting a control valve
From flow, pressure drop and specific gravity to Kv: four steps to correct sizing.
Kv expresses the water flow through a valve in m³/h at a pressure drop of 1 bar. For liquids the basic formula is Kv = Q × √(SG / ΔP), where Q is flow, SG specific gravity and ΔP the pressure drop across the valve.
A 20–30% margin is added to the result and a model is chosen that stays 60–80% open in normal operation. An oversized valve runs nearly closed, control becomes unstable and seats wear quickly.
