Patent ID: 7669473
Filing Date: 2010-03-02
Classification: B64D,G01F,G01N

Abstract:
1. A system for dynamically monitoring an amount of a liquid contained in a tank having a tank bottom, the liquid contained in the tank has a level that bounds free space in the tank above the liquid lever, said system comprising: at least one sensor conduit comprising a first fluid-delivery tube extending from a proximal end exterior of the tank to a distal open end located within the tank proximate the tank bottom; a reference conduit comprising a second fluid-delivery tube extending from a proximal end exterior of the tank to a distal open end located within the tank at a predetermined height above the tank bottom which defines a vertical spacing h between the first fluid-delivery tube open end and the second fluid-delivery tube open end; a regulating valve in each of the first and second fluid-delivery tubes exterior of the tank for delivering a substantially constant volume flow of a fluid to the distal open end of each of the first and second fluid-delivery tubes; a pressure sensor in each of the first and second fluid-delivery tubes between the regulating valve and the tank for dynamically measuring a current pressure in each of the sensor conduit and the reference conduit, the pressure sensor in said first fluid-delivery conduit is connected to said free space; and a controller for receiving the current pressure measurements from the pressure sensors in the first and second fluid-delivery tubes and operable for continuously calculating at least one of the current weight of the liquid contained in the tank as a function of the measured current pressure in the sensor conduit, the density of the liquid contained in the tank as a function of a fraction in which the numerator is a pressure difference between the measured pressures in the first and second fluid-delivery tubes and the denominator is the vertical spacing h, and the current volume of the contained liquid as a function of a fraction in which the numerator is the calculated current weight of the contained liquid and the denominator is the calculated density of the contained liquid, wherein the pressure sensor in said first fluid-delivery tube continuously outputs to said controller a pressure difference between said first fluid-delivery conduit and said free space.