METHOD FOR OPERATING A CORIOLIS MASS FLOWMETER AND CORIOLIS MASS FLOWMETER
First Claim
1. Method for determining occurrence of a condition affecting accuracy of measurements produced during operation of a Coriolis mass flowmeter that comprises at least one measuring tube, at least one oscillation generator, at least two oscillation sensors, and at least one control and evaluation unit, the oscillation generator and the oscillation sensors being arranged on the measuring tube, the method comprising:
- directing a flow of medium through the measuring tube,causing the oscillation generator to put the measuring tube into a harmonic oscillation with an excitation frequency f0 and an excitation amplitude A0,using the first and the second oscillation sensors to detect the oscillation of the measuring tube,forwarding oscillation detected by the first oscillation sensor to the control and evaluation unit as a first measuring signal,forwarding oscillation detected by the second oscillation sensor to the control and evaluation unit as a second measuring signal, anddetermining at least one comparison measurement signal from at least one of the first measuring signal and the second measuring signal,based on the excitation frequency f0 and the excitation amplitude A0, determining an expected value of at least one of the amplitude, phase and a variable derived therefrom at at least one evaluation frequency,wherein the evaluation frequency corresponds to the excitation frequency f0 and/or at least to a harmonic of the excitation frequency f0,detecting at least one of the amplitude, the phase and the variable derived therefrom of the comparison measurement signal exclusively at the evaluation frequency,comparing the expected value of the at least one of the amplitude, the phase and the variable derived therefrom to a corresponding value of the comparison measurement signal and determining a measure for a deviation of the expected value,issuing an alert when the deviation of the expected value exceeds an upper limit value or falls below a lower limit value, anddetermining the existence of a mechanical problem with the flowmeter when an alert is issued.
1 Assignment
0 Petitions
Accused Products
Abstract
A method for operating a Coriolis mass flowmeter having at least one measuring tube, at least one oscillation generator, at least two oscillation sensors, and at least one control and evaluation unit, the oscillation generator and the oscillation sensors being arranged on the measuring tube, wherein the measuring tube has a medium flowing through it, wherein the oscillation generator puts the measuring tube into a harmonic oscillation with the excitation frequency f0 and the excitation amplitude A0, wherein the first and the second oscillation sensors detect the oscillation of the measuring tube and wherein the first oscillation sensor forwards the oscillation to the control and evaluation unit as first measuring signal and wherein the second oscillation sensor forwards the oscillation to the control and evaluation unit as second measuring signal, and wherein at least one comparison measurement signal is determined from the first measuring signal and/or the second measuring signal.
8 Citations
10 Claims
-
1. Method for determining occurrence of a condition affecting accuracy of measurements produced during operation of a Coriolis mass flowmeter that comprises at least one measuring tube, at least one oscillation generator, at least two oscillation sensors, and at least one control and evaluation unit, the oscillation generator and the oscillation sensors being arranged on the measuring tube, the method comprising:
-
directing a flow of medium through the measuring tube, causing the oscillation generator to put the measuring tube into a harmonic oscillation with an excitation frequency f0 and an excitation amplitude A0, using the first and the second oscillation sensors to detect the oscillation of the measuring tube, forwarding oscillation detected by the first oscillation sensor to the control and evaluation unit as a first measuring signal, forwarding oscillation detected by the second oscillation sensor to the control and evaluation unit as a second measuring signal, and determining at least one comparison measurement signal from at least one of the first measuring signal and the second measuring signal, based on the excitation frequency f0 and the excitation amplitude A0, determining an expected value of at least one of the amplitude, phase and a variable derived therefrom at at least one evaluation frequency, wherein the evaluation frequency corresponds to the excitation frequency f0 and/or at least to a harmonic of the excitation frequency f0, detecting at least one of the amplitude, the phase and the variable derived therefrom of the comparison measurement signal exclusively at the evaluation frequency, comparing the expected value of the at least one of the amplitude, the phase and the variable derived therefrom to a corresponding value of the comparison measurement signal and determining a measure for a deviation of the expected value, issuing an alert when the deviation of the expected value exceeds an upper limit value or falls below a lower limit value, and determining the existence of a mechanical problem with the flowmeter when an alert is issued. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A Coriolis mass flowmeter comprising:
-
at least one measuring tube, at least one oscillation generator on the at least one measuring tube for producing a harmonic oscillation of the at least one measuring tube with an excitation frequency f0 and an excitation amplitude A0, at least two oscillation sensors on at least one measuring tube for detecting oscillation of the measuring tube, and at least one control and evaluation unit, wherein the first and the second oscillation sensors connected to the at least one control and evaluation unit so as to forward the oscillation detected to the control and evaluation unit as first and second measuring signals, respectively, and wherein the at least one control and evaluation unit comprises; means for producing at least one comparison measurement signal using at least one of the first measuring signal and the second measuring signal, means for determining an expected value of at least one of amplitude, phase and at least one variable derived therefrom based on the excitation frequency f0 and the excitation amplitude A0 at at least one evaluation frequency, means for detecting the at least one of the amplitude and the phase and the variable derived therefrom of the comparison measurement signal exclusively at the evaluation frequency, means for comparing the expected value to a corresponding value of the comparison measurement signal and for determining a measure of deviation of the comparison measurement signal from the expected value, and means for issuing an alert when the deviation determined exceeds an upper limit value or falls below a lower limit value. - View Dependent Claims (9, 10)
-
Specification