AN ELECTRICALLY PASSIVE FLUID LEVEL GAUGE BASED ON AN ACOUSTIC RESONATOR

This paper describes a novel electrically passive fluid level gauge. I t is based on a one-dimensional low-frequency acoustic gas resonator. The acoustical power is delivered to the resonator an the acoustic wav eguide and a fibre-optic microphone is used as an acoustic pressure se nsor. Distances of over 100 m between the electrically passive sensor and the electrically active controller were achieved in practice. The proposed method can be successfully implemented in systems where probl ems of residues, deposits, foams, etc, can be expected.