METHOD OF INDICATING AVAILABILITY OF LIQUID IN RESERVOIR AND DEVICE FOR REALISING SAID METHOD Russian patent published in 2010 - IPC G01F23/00 

FIELD: physics.

SUBSTANCE: in a detecting element - a resonator, which is selected such that its two resonance frequency values when it is partially filled, which are related to corresponding frequency values for the resonator when it is not filled with control liquid f_p1 and f_p2, do not coincide, electromagnetic oscillations are excited on one of the said resonance frequencies and that frequency is measured. Oscillations are excited on the other resonance frequency which is then measured. The linear combination value of the measured resonance frequencies f₁ + a·f₂, where a = -f_p1/ f_p2. Availability of liquid is determined from the value of one of the measured resonance frequencies when this linear combination equals zero. The detecting element is made in form of a closed conductor which is uniformly distributed inside a dielectric pipe. The diametrically opposite points of the said conductor at the butt end of the pipe are connected to capacitor elements which are inserted into each other. There is a switch, through which a signal is transmitted from one of the generators to the input of a threshold element which is controlled by the signal from the zero detector of the linear combination of the measured resonance frequencies.

EFFECT: more reliable indication of availability of liquid in reservoirs and pipes under varying temperature and pressure conditions and properties of the liquid, including under conditions of possible presence of liquid on the detecting element.

2 cl, 3 dwg