Method for operating a coriolis mass flowmeter and respective coriolis mass flowmeter

Patent metadata

Field	Value
Publication number	US-2017016751-A1
Application number	US-201615210216-A
Country	US
Kind code	A1
Filing date	Jul 14, 2016
Priority date	Jul 17, 2015
Publication date	Jan 19, 2017
Grant date	—

Abstract

Described and shown is a method for operating a Coriolis mass flowmeter ( 1 ) having at least one measuring tube ( 2 ), an oscillation exciting device ( 3 ) for exciting the measuring tube ( 2 ) to an oscillation ( 4 ), at least a first oscillation sensor ( 5 ) and a second oscillation sensor ( 6 ) and at least a first sensor signal path and a second sensor signal path. The object of the invention is to provide a method in which the measuring accuracy is increased compared to the prior art. The object is achieved in that at least one first test signal is generated having at least one first test signal frequency, that the at least first test signal is fed at least into the first sensor signal path and into the second sensor signal path, that the at least first test signal is guided by the first sensor signal path over the first oscillation sensor ( 5 ) and by the second sensor signal path over the second oscillation sensor ( 6 ), that a test signal propagation time difference of at least the first test signal is determined at least between the first sensor signal path and the second sensor signal path, and that a sensor signal propagation time difference between a first sensor signal and a second sensor signal is compensated with the test signal propagation time difference. Additionally, the invention relates to a corresponding Coriolis mass flowmeter.

First claim

What is claimed is:

1 . Method for operating a Coriolis mass flowmeter ( 1 ) having at least one measuring tube ( 2 ), an oscillation exciting device ( 3 ) for exciting the measuring tube ( 2 ) to an oscillation ( 4 ), at least a first oscillation sensor ( 5 ) and a second oscillation sensor ( 6 ) and at least a first sensor signal path and a second sensor signal path,
characterized in that at least one first test signal is generated having at least one first test signal frequency, that the at least first test signal is fed at least into the first sensor signal path and into the second sensor signal path, that the at least first test signal is guided by the first sensor signal path over the first oscillation sensor ( 5 ) and by the second sensor signal path over the second oscillation sensor ( 6 ), that a test signal propagation time difference of at least the first test signal is determined at least between the first sensor signal path and the second sensor signal path, and that a sensor signal propagation time difference between a first sensor signal and a second sensor signal is compensated with the test signal propagation time difference.

2 . Method according to claim 1 , characterized in that the frequency dependency of the transmission behavior of at least the first sensor signal path is taken into account during compensation of the sensor signal propagation time difference.

3 . Method according to claim 1 , characterized in that at least the first test signal is generated having a frequency spectrum that is free of the frequency of the oscillation.

4 . Method according to claim 3 , characterized in that at least the first test signal is generated having a frequency spectrum that is below the frequency of the oscillation and at least a second test signal is generated having a frequency spectrum that is above the frequency of the oscillation.

5 . Method according to claim 4 , characterized in that the sensor signal propagation time difference is determined by interpolation using at least the test signal propagation time difference of the first test signal and the test signal propagation time difference of the second test signal.

6 . Method according to claim 4 , characterized in that the transmission function of the first signal path is determined using at least the test signal propagation time difference of the first signal and the test signal propagation time difference of the second test signal.

7 . Coriolis mass flow meter ( 1 ) having at least one measuring tube ( 2 ), an oscillation exciting device ( 3 ) for exciting the measuring tube ( 2 ) to an oscillation ( 4 ), at least a first oscillation sensor ( 5 ) and a second oscillation sensor ( 6 ), an evaluation unit ( 7 ) and at least a first sensor signal path and a second sensor signal path,
wherein each of the oscillation sensors ( 5 , 6 ) is arranged at a measuring tube point ( 8 , 9 ), has a first sensor connection ( 10 , 11 ) and a second sensor connection ( 12 , 13 ) and is designed for output of a sensor signal representing the oscillation ( 4 ) at the measuring tube point ( 8 , 9 ) between the first sensor connection ( 10 , 11 ) and the second sensor connection ( 12 , 13 ), wherein the evaluation unit ( 7 ) has a digitization unit ( 14 ) having at least a first digitization channel ( 15 ) and a second digitization channel ( 16 ), wherein each of the digitization channels ( 15 , 16 ) has at least a first analog signal input ( 17 , 18 ), wherein each of the sensor signal paths has an output signal path ( 19 , 20 ) and an input signal path ( 21 , 22 ), wherein the beginning of each of the output signal paths ( 19 , 20 ) is located in the evaluation unit ( 7 ) and the end of each of the output signal paths ( 19 , 20 ) is connected to a respective first sensor connection ( 10 , 11 ) of one of the oscillation sensors ( 5 , 6 ) and the beginning of each of the input signal paths ( 21 , 22 ) is each connected to a respective second sensor connection ( 12 , 13 ) of one of the oscillation sensors ( 5 , 6 ) and the end of each of the input signal paths ( 21 , 22 ) is connected to a respective first analog signal input ( 17 , 18 ) of one of the digitization channels ( 15 , 16 ), wherein the beginning of each of signal sensor paths coincides with the beginning of the respective output signal path ( 19 , 20 ) and the end of each of the sensor signal paths coincides with the end of the respective input signal path ( 21 , 22 ), and wherein the evaluation unit ( 7 ) is designed for determining a mass flow of a medium ( 23 ) flowing through the measuring tube ( 2 ) using the phase difference caused by the flow of the medium ( 23 ) between at least the first sensor signal and the second sensor signal, characterized in that the evaluation unit ( 7 ) has a test signal generator ( 24 ) having a test signal output ( 25 ), a test signal path ( 26 ) and a signal connecting device ( 27 ) having at least a first signal connecting input ( 28 ) and a signal connecting output ( 29 ), that the test signal generator ( 24 ) is designed to generate at least a first test signal having at least a first test signal frequency, that the test signal path ( 26 ) is connected to the test signal output ( 25 ) and to the first signal connecting input ( 28 ), that the signal connecting output ( 29 ) is connected at least to the beginning of the first output signal path ( 19 ) and the beginning of the second output signal path ( 20 ), that the evaluation unit ( 7 ) is designed to determine a test signal propagation time difference of at least the first test signal at least between the first sensor signal path and the second sensor signal path and to compensate a sensor signal propagation time difference between a first sensor signal and a second sensor signal with the test signal propagation time difference.

8 . Coriolis mass flowmeter ( 1 ) according to claim 7 , characterized in that the evaluation unit ( 7 ) is designed to take into account the frequency dependency of the transmission behavior of at least the first sensor signal path in compensating the sensor signal propagation time difference.

9 . Coriolis mass flowmeter ( 1 ) according to claim 7 , characterized in that the test signal generator ( 24 ) is designed to generate at least the first test signal having a frequency spectrum that is free of the frequency of the oscillation ( 4 ).

10 . Coriolis mass flowmeter ( 1 ) according to claim 9 , characterized in that the test signal generator ( 24 ) is designed to generate at least a first test signal with a frequency spectrum that is below the frequency of the oscillation ( 4 ) and is designed to generate at least a second test signal with a frequency spectrum that is above the frequency of the oscillation ( 4 ).

11 . Coriolis mass flowmeter ( 1 ) according to claim 10 , characterized in that the evaluation unit ( 7 ) is designed to determine the sensor signal propagation time difference by interpolation using at least the test signal propagation time difference of the first test signal and the test signal propagation time difference of the second test signal.

12 . Coriolis mass flowmeter ( 1 ) according to claim 10 , characterized in that the evaluation unit ( 7 ) is designed to determine the transmission function of at least the first signal path using at least the test signal propagation time difference of the first test signal and the test signal propagation time difference of the second test signal.

13 . Coriolis mass flowmeter ( 1 ) according to claim 7 , characterized in that the test signal generator ( 24 ) has a digital-to-analog converter for generating the test

Assignees

• Krohne Messtechnik Gmbh

Inventors

• Erkelenz Alexander
• STROM Ralf

Classifications

• G01F1/849

  having straight measuring conduits · CPC title

• G01F1/8422 Primary

  exciters · CPC title

• G01F1/8436

  signal processing · CPC title

• G01F1/8431 Primary

  electronic circuits · CPC title

• G01F25/10

  of flowmeters · CPC title