| 摘要 |
The two combined transmitter/receivers (2,3) are respectively arranged upstream and downstream for the flowing fluid in the measured length (1). The transmitter/receiver transducers are acted on alternately with an ultrasonic frequency generated by a generator (12), and are operated alternately to receive analogous signals in the flow direction and against the flow direction. With the first measurement, the time and/or the phase difference between one or more specified signal levels is given at one of the two timers, during the measuring of the phase fixed reference signal for the transmitter signal. In addition one or more predetermined signal levels are transmitted from the first transducer, received and measured at the second transducer. With the second measurement, both transducers are used in a reversed operating mode. The difference of the two measurements is used for determining the through flow amount of the fluid. |
