A method for determining at least one tube wall resonant frequency, as well as clamp - on - ultrasound - flow meter

摘要

A method for determining at least one tube wall resonance frequency of a pipeline in the region of a measuring point by means of a field device process measurement technology with at least a first ultrasonic transducer, which at the measuring point on the pipeline is fixed, comprising the steps of:I providing a first transfer function u_transducer(f) of at least the first or more ultrasonic transducers located in the region of the measuring point;Ii determination of a reception spectrum u_rec(f) from a received signal u_rec(t) after the transmission of an ultrasonic signal;Iii determining a second transfer function u_{Measuring point}(f) from the first transfer function u_transducer(f) of the first or of the plurality of ultrasonic transducer and the reception spectrum u_rec(f), wherein the second transfer function u_{Measuring point}(f) is characteristic for the measurement location; andIv determination of the at least one tube wall resonant frequency f._res, in particular a plurality of resonant frequencies, in the region of the measuring point by evaluation of the second transfer function u_{Measuring point}(f) of step iii,as well as a clamp - on - ultrasound - flow meter, a method for determining a flow rate, a method for determining the change in the measuring point and an identification device.