FIELD: machine building.
SUBSTANCE: one version of design describes drive (40) that receives the first signal (55) causing the vibration at least of one pipeline (20) at resonance frequency, and the second signal (56) causing the vibration at least of pipeline (20) at the frequency differing from resonance frequency. One version of the design describes the drive (140) that alternates the reception of control signal (155) causing the vibration at least of one pipeline (120) at resonance frequency and signal of sensor (145) for measurement of movement at least of one pipeline (120). The other version of the design describes one or several electronic devices (50, 150) which determine the mode of vibrations at least of one pipeline (20, 120) and compare the determined vibration mode to one or several reference vibration modes for determination of the fact whether the substance flows at least in one pipeline (20, 120).
EFFECT: higher accuracy.
10 cl, 4 dwg
