US 11,788,875 B2
Measurement pickup for determining the mass flow rate of a liquid
Hao Zhu, Freising (DE); and Rémy Scherrer, Oberdorf (FR)
Assigned to Endress+Hauser Flowtec AG, Reinach (CH)
Appl. No. 16/629,071
Filed by Endress+Hauser Flowtec AG, Reinach (CH)
PCT Filed Jun. 19, 2018, PCT No. PCT/EP2018/066273
§ 371(c)(1), (2) Date Jan. 7, 2020,
PCT Pub. No. WO2019/007679, PCT Pub. Date Jan. 10, 2019.
Claims priority of application No. 10 2017 115 251.2 (DE), filed on Jul. 7, 2017.
Prior Publication US 2020/0191632 A1, Jun. 18, 2020
Int. Cl. G01F 1/84 (2006.01)
CPC G01F 1/8477 (2013.01) [G01F 1/8422 (2013.01); G01F 1/8427 (2013.01); G01F 1/8436 (2013.01)] 11 Claims
OG exemplary drawing
 
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.