Valve Cv Si Units
Cv and kv are singles values in units of flowrate that may be used to characterise the relationship between flowrate and pressure loss for fittings and equipment.
Valve cv si units. Such as the renault number (reynolds number), flow rate (flow), the shock (choking), the involved joints in pipes (fitting) and the other by the values of these. It is defined as the flow rate in us gallons per minute [gpm] of water at a temperature of 60º fahrenheit with a pressure drop across the valve of 1 psi. Online calculator to quickly determine valve and orifice cv & kvs values for air.
Valves are tested by running water through it before publishing the cv value. Cv = valve sizing coeffecient q = flow in gallons per minute u = viscosity in centipoise sg = density liquid / density water @ 60f p1 = upstream pressure in psi (psi) p2 = downstream pressure in psi (psi) n1 = 1.0, units constant n10 = 52.3, units constant fp = 1.0, correction factor for piping around valve (adjust for your conditions) fr = 1.0. Q = valve flow rate in gallons per minute (us gpm) δp = difference between upstream and downstream pressure in
The sg and psi units are the same as for the american cv. If flow capacity required is known and valve selection is desired, to calculate cv with the following formulaes and select appropriate valve from the manufacturers cv factor chart (at 15 °c) with a delta p of 1 bar across the valve.
For example, you can calculate required control valve capacity (cv or kv) for minimum, normal, maximum and one additional flow condition. In metric units, the same valve with cv = 1 pass 0.864 m3/hr. Flow for a given cv is typically calculated from the following formula.
The units of cv (in the us) are usgpm/(psi 0.5). Cv by definition is the number of gallons per minute (gpm) a valve will flow with a 1 psi pressure drop across the valve. Cv is the flow coefficient in imperial units.
It describes the relationship between the pressure drop across an orifice valve or other assembly and the corresponding flow rate. [m3/h] for a pressure drop of 1 psi [1 bar] across a flow passage [flow coefficient: Gallons per minute that passes through a valve at a pressure drop of 1 psi.