Patent ID: 7520180
Filing Date: 2009-04-21
Classification: G01F

Abstract:
1. A method to operate a measuring apparatus ( 1 ) to determine a flow rate of flowable media through a measuring sector ( 3 ), with the measuring apparatus ( 1 ) comprising at least two ultrasonic transceivers ( 4 ) as sensors to expose the measuring sector ( 3 ) to sonic waves in and against a direction of flow and to detect signals, and which is operated via an ultrasonic phase difference method, the sensors are each alternately operated as transmitters and receivers, the sensors are operated with an adjustable alternating current having a constant frequency, with transmitting periods of the transmitter being longer than a receiving period of the receiver, and the flow rate being determined by at least the following steps: exposing the measuring sector ( amplifying the signal, A/D-conversion, forming threshold values, determining and storing a respective phase position H, exposing the measuring sector ( amplifying the signal, A/D-conversion, forming threshold values, determining and storing the respective phase position R, forming a difference of the phase values depending on the direction of flow, correcting the phase difference value with a factor depending on the diameter.