PROCEDURE CONTROLLING LEVEL OF LIQUID Russian patent published in 2002 - IPC

FIELD: control over level of liquid in fuel tank of aircraft. SUBSTANCE: two temperature-sensitive resistors connected in series are installed for realization of procedure controlling level of liquid in controlled tank, values of their rated resistance are measured, resistors are heated by current of their common power supply source and then their resistance is determined again under steady state. In this case there are employed temperature-sensitive resistors which temperature coefficients have same sign and relation of parameters of heat release and convective heat exchange in gas secures heating of temperature- sensitive resistors by current to different temperatures. Resistance of each temperature- sensitive resistor is measured individually and ratio of values of measured resistance is determined. If it is equal to ratio of rated values of resistance of resistors then judgment on presence of liquid is made. Temperature-sensitive resistors can have different rated values of resistance but their coefficients of convective heat exchange in gas are equal or parameters of convective heat exchange in gas can be different but their rated values of resistance are equal. EFFECT: exclusion of any possibility of generation of false signal on absence of liquid in tank when this procedure is used in wide range of uncorrelated temperatures of gas and liquid. 2 cl, 1 dwg