Patent ID: 7370528
Filing Date: 2008-05-13
Classification: G01F

Abstract:
1. System for detecting the level of a liquid in a tank, comprising: at least two electrodes extending into the inside of said tank, in contact with said liquid, said electrodes constituting a capacitor, the capacitance of which is variable in relation to the level of the liquid in said tank, detecting means electrically connected to said electrodes, and a control unit suitable for controlling said detecting means, wherein said detecting means comprise a resistance connected in series to said capacitor and a current generator connected in series between said resistance and said capacitor, said current generator being suitable for being activated by said control unit for powering said resistance and for charging said capacitance with said current until a predefined voltage is reached on the terminals of said capacitance, during a corresponding charge time, representative of the current level of said liquid in said tank, and wherein said control unit is prearranged for storing said charge time in a memory and for activating at later times said generator for a duration equal to said stored charge time, so that said capacitance is charged with a current such as to produce on said capacitance a voltage drop proportional to the variation of said capacitance caused by a corresponding variation of the level of said liquid.