Verfahren zur Messung von Strömungsgeschwindigkeiten mit Ultraschall

摘要

1. A method of measuring the rate of flow of a liquid or gaseous medium using ultrasonics, with a measuring section located between two ultrasonic transducers (1, 2) and traversed by the medium whose flow direction includes at least one component in the direction of the measuring section, where the two ultrasonic transducers (1, 2) are periodically operated alternately as transmitter and receiver in order to produce two ultrasonic propagation directions, where the ultrasonic radiation is produced by a voltage-controlled oscillator (3) whose output is connected via a transmitting stage (4) to an ultrasonic transducer (1, 2), and whose frequency is regulated in both propagation directions by a phase-regulating circuit such that the phase position of the received ultrasonic signal is identical in both propagation directions, and the rate of flow is determined by digital analysis of the difference between the two frequencies obtained in this way, characterised in that in each propagation direction, following a settling time of the phase-regulating circuit, the control signal of the oscillator (3) is stored, that the rate of flow is determined by a calculating circuit during a following analysis time (DELTA t1 , DELTA t1 * , DELTA t2 , DELTA t2 * ), and that during the analysis time the transmitting stage (4), the receiver (5) for ultrasonic radiation, and the phase regulator (6) are cut off from the operating voltage, the output of the oscillator (3) is cut off from the following transmitting stage (4), and the control input of the oscillator (3) is cut off from the phase regulator (6).