Solenoid and Process Valve Engineering Data. We have compiled a list of liquid flow and air flow formulae to allow users to calculate solenoid valve flow and pressure drop which are the key factors when choosing any solenoid, angle seat or process valve. This helps make sure systems will have sufficient flow, the correct valve size so avoiding additional costs or valve failure. A complete media viscosity cross reference guide as liquid media thickness can be measured in various formats so in this way engineers will avoid installing a solenoid or process valve that would not be compatible with the media being controlled. The compete IP Ingress Protection Chart, pressure, volume, flow, temperature and length cross reference guides to help.  Liquid Flow Formulae  Air Flow Formulae  Q=Kv x Square Root of (DP/d) or DP=d(Q/Kv)^{2}  Where DP less than P1/2  Where DP equal to P1/2  Q=1.69Kv x Sq Rt (DPxP^{2})  Q = 0.84Kv x P^{1}  Q = Flow L/Min DP = Pressure Drop (Bar) d = density i.e. Water = 1 Kv = flow factor coefficient of valve (L/Min) (N.B. DP 5  10% is preferred)  Q = Flow (M^{3 }Hr) DP = Pressure Drop (Bar) Kv = flow factor coefficient of valve (M^{3 }Hr) P1 = inlet pressure + 1 bar P² = absolute downstream pressure =(inlet pressure + 1 bar  DP)  Saybolt Universal (seconds)  Engler (degrees)  Kinematic (centistokes)  Saybolt Universal (seconds)  Engler (degrees)  Kinematic (centistokes)    1.05*  1.5  103  3.0  21.3  34  1.15*  2.5  109  3.2  22.8  37  1.25*  3.4  115  3.4  24.1  40  1.3*  4.2  125  3.7  26.7  42  1.4*  5.0  137  4.0  29.2  45  1.45*  5.7  148  4.3  31.7  50  1.6*  7.5  160  4.6  34.2  57  1.8*  9.4  171  4.9  36.8  62  1.9  11.0  183  5.2  39  68  2.1  12.6  205  5.9  44  74  2.2  14.2  242  7  50  79  2.4  15.5  256  7.3  55  85  2.6  17.0  285  8.1  62  92  2.7  18.6  313  8.9  68  98  2.9  20.0  342  9.8  74 
 PRESSURE 1 Bar = 14.5 PSI 1 Bar = 100 kPa (Kilopascal) 1 PSI = 6.9 kPa 1 Kg/cm² = 0.98 Bar 1 Atmosphere = 1.013 Bar 1 Inch Water gauge = 2.49 mbar 1 mm Mercury = 1.33 mbar 1 Ton / in² = 154 Bar Volume 1 Gallon (UK) = 4.54 Litres 1 Gallon (USA) = 3.79 Litres 1 Pint (UK) = 0.57 Litres 1 Pint (USA) = 0.47 Litres 1 Fluid Once (UK) = 28.4 cm³ 1 Fluid Once (USA) = 29.6 cm³ FLOW 1 CFM = 0.472 Litres a second 1 CFM = 0.000472 m³/Sec 1 CFM = 28.32 Litres a minute Temperature From °F to C° Add 40 then multiply by 5 then divide by 9 then 40 From C° to F° Multiply by 9 then –40 divide by 5 then +40 Length 1 Inch = 25.4mm 1/16” Inch = 1.5875mm 1 foot = 0.305 Meters 1 Mile = 1.609 Kilometre  Degrees Of Protection Provided By Electrical Enclosures (IP rating  1st No  Definition  Test Type  2nd No  Definition  Test Type  1  Protected against objects Ø 50mm   1  Protected against vertically falling water drops   2  Protected against objects Ø 12.5mm   2  Protected against vertically falling water drops up to 15 degrees inclination   3  Protected against objects Ø 2.5mm   3  Protected against vertically falling water drops up to 60 degrees inclination   4  Protected against objects Ø 1mm   4  Protected against splashed water in any direction   5  Dust Protected   5  Protected against water jets from any direction   6  Dust Tight   6  Protected against powerful water jets from any direction      7  Protected against temporary water immersion      8  Protected against the effects of submersion  

Definitions and conversion factors for the three valve flow coefficients Kv, Cv and Qn. 1. What is the Kv Value? 2. What is the Cv Value? 3. What is the Qn Value? 4. Converting between Kv, Cv & Qn 1. What is the Kv Value? Kv value is the metric measure for the flow of a valve. It is defined as: The volume flow in cubic metres per hour of water at a temperature of between 5° and 40° Celsius with a pressure drop across the valve of 1 bar. 2. What is the Cv Value?
Cv is the imperial measure for the flow of a valve. It is defined as: The volume flow in US gallons per minute of water at a temperature of 60° Fahrenheit with a pressure drop across the valve of 1 psi. 3. What is the Qn Value?
Qn value is used in pneumatics to define the flow of a valve. It is defined as: The volume flow in litres per minute of air at a temperature of 20° Celsius, with an input pressure of 6 bar and a pressure drop across the valve of 1 bar. 4. Converting between Kv, Cv & Qn
Kv = 0.86 x Cv Kv = Qn / 1078
Cv = Kv / 0.86 Cv = Qn x 0.0008
Qn = Kv x 1078 Qn = Cv / 0.0008   