Method and apparatus for determining a change of the flow state of flowable substances from its static state to its flowing state or vice verse

摘要: A method and apparatus for determining a change of the flow state flowable substance by transmitting ultrasonic or ultrasound waves constant frequency to spatial region substance, receiving backscattered converting into primary signal which is amplitude- phase-modulated in accordance with backscattering demodulating order obtain modulation signal. This can be divided spectrum components different possessing pseudo periods are defined as time intervals between successive momentary values signal, such corresponding one another. The duration predetermined number compared duration.