FIELD: checking technology. SUBSTANCE: device has two inclined acoustic transducers (radiator and receiver of ultrasonic signal) positioned on external surface of reservoir and spaced at some definite distance from each other in plane parallel to surface of liquid being checked, and electronic device. Ultrasonic signal is formed and divided into two components: normal and longitudinal. Ultrasonic signal is received by identical acoustic receiver. Place of receiver installation is determined by input point of longitudinal wave. Received signal is amplified, and amplitude values of every wave are separated in it by strobing. Then they are detected, normalized, states of zeros "O" and units "1" are assigned to normalized values. Then these states are compared, summed up logically, integrated, compared with preset threshold, and respective signal is generated at output. EFFECT: higher reliability and accuracy. 2 dwg
