Patent ID: 7347089

Claim:
A method for determining a liquid volume (V C ) in a container, said container containing at least one compressible gas and the liquid, independent of the shape of the container and any structures therein and independent of temperature, said method comprising: producing a volumetric displacement (ΔV G ) in the container, and measuring a pressure change (ΔP) caused therein; determining the liquid volume (V C ) with the following formula: V C =V T −V G wherein: V T is the reference container volume, and V G is the gas volume measurement correlation (K P ΔV G /ΔP), wherein K is in a range from 1 to C P /C V , wherein C P is the constant pressure heat capacity of the gas and C V is the constant volume heat capacity of the gas, wherein when said gas is a real gas, K equals 1+ZR/C V , wherein Z is the gas compressibility factor and R is the gas constant.