Patent ID: 6782339
Filing Date: 2004-08-24
Classification: F17C,G01F,Y02E

Abstract:
A method of determining a volume of liquefied gas in a cryogenic storage tank having a liquid space and a head space, comprising the steps of:entering and storing the dimensions and orientation of the storage tank; entering and storing the type of liquefied gas contained in said tank; entering and storing a stratification coefficient; storing a lookup table of density constants, stored according to the estimated average pressure, and liquid type; measuring the differential pressure between the liquid space and the head space; measuring the pressure at the head space; calculating an estimated average pressure using the measured head pressure and the stratification coefficient; reading a liquid density value from the look-up table of density constants using the calculated estimated average pressure and the entered liquid type; and computing a liquid volume in said tank as a function of said differential pressure, liquid density, tank dimensions, tank orientation, and type of liquefied gas.