CPC G01F 1/8477 (2013.01) [G01F 1/8422 (2013.01); G01F 1/8427 (2013.01); G01F 1/8436 (2013.01)] | 11 Claims |
1. A measurement pickup for determining the mass flow rate of a liquid measured medium, the measurement pickup comprising:
a measurement tube for carrying the liquid measured medium, wherein the measurement tube has an inlet-side end section and an outlet-side end section;
a support body on which the measurement tube is mounted in a region of the inlet-side end section and in a region of the outlet-side end section;
an exciter for exciting vibrations of the measurement tube in at least one vibration mode;
at least two vibration sensors for detecting vibrations of the measurement tube and for outputting vibration-dependent signals; and
an operating and evaluation circuit for driving the exciter, for receiving the vibration-dependent signals of the at least two vibration sensors, and for calculating a sequence of mass flow rate measured values as a function of a sequence of time-discrete phase difference values between the vibration-dependent signals of the at least two vibration sensors,
wherein the operating and evaluation circuit includes an adaptive low-pass filter for filtering the sequence of the mass flow rate measured values,
wherein the adaptive low-pass filter has a filter parameter dependent on a gas content of the liquid measured medium, and
wherein the operating and evaluation circuit is designed to calculate the filter parameter as a function of a gas-content-dependent fluctuation of a natural frequency of the measurement tube vibration.
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