The table above presents the Flow Coefficients (Cv) for Apollo® Top Entry Ball Valves. This number represents the flow (in gallons per minute of water) required to produce a 1 psig pressure drop across the valve. The data shown is for a valve in the full open position. Data for various degrees of open are available upon request. The values shown represent the average for several tests which highlighted the variability of Flow Coefficients. It is not unreasonable to expect a 10% to 20% deviation for a specific valve from the nominal figures shown.

Knowing specific system characteristics; such as line size, flow rate, temperature and pressure and knowing specific fluid characteristics; such as specific gravity, density, or compressibility factor allows the verification of the pressure drop across a known valve. Or conversely, in the absence of a valve size and knowing an acceptable pressure drop under the described flow conditions it is possible to select an appropriately sized valve

Flow of Liquids
or	Where: Q= Flow in US GPM PD= Pressure Drop (PSI) SG= Specific Gravity at Flow Conditions CV= Valve Flow Coefficient

Flow of Gases
or	Where: Q= Flow in US GPM PD= Pressure Drop (PSI) P2= Outlet Pressure PSIA T= Temp. (R°) (F°+460) SG= Specific Gravity at Flow Conditions CV= Valve Flow Coefficient