Saturated Steam

Steam Temperature	Inlet Pressure	Flow Coefficient	Volumetric Flow	Pressure Drop ΔP
Celsius (°C)	mm Water Column	Cv	kg/h	PSI

Air & Gases

Fluids	Inlet Pressure	Flow Coefficient	Volumetric Flow	Pressure Drop ΔP	Fluid Temperature
Ozone	torr = mmHg	kv	m3/h	mWatercolumn	Celsius (°C)

Water & Liquids

Liquids	Inlet Pressure	Flow Coefficient	Volumetric Flow	Pressure Drop ΔP
Diesel Fuel	bar	Kv	bar	m3/h

Approx.Kv Approx.Φ 0,05 1,2mm 0,17 2,4mm 0,45 4,8mm 0,6 6,4mm 1,7 9,0mm 3,0 13,0mm 4,0 16,0mm 4,5 18,0mm 6,5 19,0mm 11,0 25,0mm 15,0 32,0mm 22,0 38,0mm 41,0 51.0mm

100.00 m3/h (Kv) =

1,670.00 l/mn (Kvh) 117.00 US gal/mn (Cv) 97.50 UK gal/mn (Cve)

Valve Sizing Calculation - Theory

Control valve sizing is based on the calculation of flow coefficient for given pressure drop and fluid flow rate. Main equitation that gives relation between flow rate and pressure drop is:

for imperial units, and:
for metric units,

where is:

Cv - flow coefficient in imperial units
Kv - flow coefficient in metric units
Dp - pressure drop through control valve
Q - fluid flow rate
G - specific gravity
ro - relative density

Flow coefficient is defined as the proportional constant between pressure drop and flow rate and it is determined experimentally by the valve manufacture. It is expressed as the flow rate of water in gpm u.s. (m3/h) for a pressure drop of 1 psi (1 bar) across a flow passage. note: (flow coefficient: Cv-imperial, Kv-metric)

Relation between volumetric and mass flow rate is calculated using well known equation:
Also, velocity or pipe diameter can be calculated using following equations:

For all valve sizing calculations please consult one of our friendly staff at Just Valves