CORIOLIS FLOWMETER, TIMING PREDICTION SYSTEM, AND TIMING PREDICTION METHOD

• US 20190242737A1
• Filed: 01/08/2019
• Published: 08/08/2019
• Est. Priority Date: 02/05/2018
• Status: Active Grant

• Current Assignee: Yokogawa Electric Corporation
• Original Assignee: Yokogawa Electric Corporation
• Inventors: CHIKEN, Yoshihiro
• Granted Patent: US 11,536,600 B2
• Time in Patent Office: Days
• CPC Class Codes: G01F 1/8436 signal processing
• CPC Class Codes: G01F 1/8459 vibrating means being located inside the measuring conduits
• CPC Class Codes: G01F 25/10 of flowmeters

Abstract

A Coriolis flowmeter includes a change ratio obtainer configured to obtain a change ratio of vibration of a vibration tube when the vibration tube is vibrated with a constant driving force by causing a switch to select a fixed gain setting voltage, a calculator configured to calculate a first parameter indicating at least one of a spring constant of the vibration tube and a damping coefficient of the vibration tube on the basis of the change ratio obtained by the change ratio obtainer and the constant driving force, and a predictor configured to predict at least one of a time, an operating time, and an integrated flow rate of a fluid flowing in the vibration tube required for a state of the vibration tube to become a state requiring maintenance, using the first parameter calculated by the calculator or a second parameter obtained by performing a predetermined calculation on the first parameter.

Claims

1. A Coriolis flowmeter comprising:

a Coriolis sensor unit configured to detect a vibration of a vibration tube to output a first output signal;

a current amplifier configured to supply a drive current for vibrating the vibration tube to the Coriolis sensor unit;

an amplifier configured to amplify the first output signal output from the Coriolis sensor unit to output a second output signal;

a smoother configured to smooth the second output signal output from the amplifier to output a third output signal;

a control amplifier configured to amplify a difference between the third output signal output from the smoother and a target voltage to output a fourth output signal;

a voltage setter configured to output a fixed gain setting voltage;

a switch configured to select one signal of the fourth output signal output from the control amplifier and the fixed gain setting voltage output from the voltage setter;

a multiplier configured to multiply the second output signal output from the amplifier by the signal selected by the switch to output a fifth output signal to the current amplifier; and

a calculation controller configured to control the voltage setter and the switch,

wherein the current amplifier is configured to amplify the fifth output signal output from the multiplier to generate the drive current,

wherein the calculation controller comprises;

a change ratio obtainer configured to obtain a change ratio of the vibration of the vibration tube when the vibration tube is vibrated with a constant driving force by causing the switch to select the fixed gain setting voltage;

a calculator configured to calculate a first parameter indicating at least one of a spring constant of the vibration tube and a damping coefficient of the vibration tube on the basis of the change ratio obtained by the change ratio obtainer and the constant driving force; and

a predictor configured to predict at least one of a time, an operating time, and an integrated flow rate of a fluid flowing in the vibration tube required for a state of the vibration tube to become a state requiring maintenance, using the first parameter calculated by the calculator or a second parameter obtained by performing a predetermined calculation on the first parameter.

2. The Coriolis flowmeter according to claim 1,

wherein the predictor is configured to calculate an approximate straight line or an approximate curve indicating a change with time of the first parameter or the second parameter or a change of the first parameter or the second parameter with respect to the integrated flow rate of the fluid, and

wherein the predictor is configured to predict at least one of the time, the operating time, and the integrated flow rate of the fluid required for the approximate straight line or the approximate curve to reach a threshold value defined as a state requiring the maintenance.

3. The Coriolis flowmeter according to claim 2,

wherein the predictor is configured to calculate the approximate straight line or the approximate curve using at least two of the first parameters or the second parameters obtained at different time.

4. The Coriolis flowmeter according to claim 2,

wherein the calculator is configured to calculate a spring constant of the vibration tube as the first parameter,

wherein the predictor is configured to calculate a first approximate straight line or a first approximate curve showing a change with time of the first parameter or the second parameter related to the spring constant or a change of the first parameter or the second parameter related to the spring constant with respect to the integrated flow rate of the fluid, and

wherein the predictor is configured to calculate at least one of the time, the operating time, and the integrated flow rate of the fluid required for the first approximate straight line or the first approximate curve to reach a first threshold value which is related to the spring constant and defined as a state requiring the maintenance.

5. The Coriolis flowmeter according to claim 2,

wherein the calculator is configured to calculate a damping coefficient of the vibration tube as the first parameter,

wherein the predictor is configured to calculate a second approximate straight line or a second approximate curve showing a change with time of the first parameter or the second parameter related to the damping coefficient or a change of the first parameter or the second parameter related to the damping coefficient with respect to the integrated flow rate of the fluid, and

wherein the predictor is configured to calculate at least one of the time, the operating time, and the integrated flow rate of the fluid required for the second approximate straight line or the second approximate curve to reach a second threshold value which is related to the damping coefficient and defined as a state requiring the maintenance.

6. The Coriolis flowmeter according to claim 1, further comprising:

a disgnoser configured to diagnose a state of the vibration tube on the basis of the first parameter calculated by the calculator.

7. The Coriolis flowmeter according to claim 1,

wherein the calculation controller further comprises:

a measurer configured to measure the flow rate of the fluid flowing in the vibration tube on the basis of the second output signal output from the amplifier.

8. The Coriolis flowmeter according to claim 1,

wherein the calculator configured to calculate an entire mass of the vibration tube on the basis of the change ratio obtained by the change ratio obtainer and the constant oscillation feedback gain.

9. The Coriolis flowmeter according to claim 8,

wherein the change ratio obtainer configured to:

calculate the change ratio α

1 on the basis of the second output signal output from the amplifier when the oscillation feedback gain is G1;

calculate the change ratio α

2 on the basis of the second output signal output from the amplifier when the oscillation feedback gain is G2; and

calculate the entire mass M of the vibration tube by dividing (G1−

G2) by (α

1−

α

2).

10. The Coriolis flowmeter according to claim 9,

wherein the change ratio obtainer is configured to measure an angular frequency ω

of the vibration of the vibration tube on the basis of the second output signal output from the amplifier, and

wherein the calculator is configured to calculate the spring constant K by multiplying M and ω

².

11. The Coriolis flowmeter according to claim 9,

wherein the change ratio obtainer is configured to measure an angular frequency ω

of the vibration of the vibration tube on the basis of the second output signal output from the amplifier, and

wherein the calculator is configured to calculate the damping coefficient D by subtracting a value obtained by multiplying α

1 and M from G1.

12. A timing prediction system comprising:

a Coriolis flowmeter; and

a calculation device connected to the Coriolis flowmeter,

wherein the Coriolis flowmeter comprises;

a Coriolis sensor unit configured to detect a vibration of a vibration tube to output a first output signal;

a current amplifier configured to supply a drive current for vibrating the vibration tube to the Coriolis sensor unit;

an amplifier configured to amplify the first output signal output from the Coriolis sensor unit to output a second output signal;

a smoother configured to smooth the second output signal output from the amplifier to output a third output signal;

a control amplifier configured to amplify a difference between the third output signal output from the smoother and a target voltage to output a fourth output signal;

a voltage setter configured to output a fixed gain setting voltage;

a switch configured to select one signal of the fourth output signal output from the control amplifier and the fixed gain setting voltage output from the voltage setter;

a multiplier configured to multiply the second output signal output from the amplifier by the signal selected by the switch to output a fifth output signal to the current amplifier; and

a calculation controller configured to control the voltage setter and the switch,

wherein the current amplifier is configured to amplify the fifth output signal output from the multiplier to generate the drive current,

wherein the calculation controller comprises;

a change ratio obtainer configured to obtain a change ratio of the vibration of the vibration tube when the vibration tube is vibrated with a constant driving force by causing the switch to select the fixed gain setting voltage; and

a calculator configured to calculate a first parameter indicating at least one of a spring constant of the vibration tube and a damping coefficient of the vibration tube on the basis of the change ratio obtained by the change ratio obtainer and the constant driving force,

wherein the calculation device comprises;

a predictor configured to predict at least one of a time, an operating time, and an integrated flow rate of a fluid flowing in the vibration tube required for a state of the vibration tube to become a state requiring maintenance, using the first parameter calculated by the calculator or a second parameter obtained by performing a predetermined calculation on the first parameter.

13. The timing prediction system according to claim 12,

wherein the predictor is configured to calculate an approximate straight line or an approximate curve indicating a change with time of the first parameter or the second parameter or a change of the first parameter or the second parameter with respect to the integrated flow rate of the fluid, and

wherein the predictor is configured to predict at least one of the time, the operating time, and the integrated flow rate of the fluid required for the approximate straight line or the approximate curve to reach a threshold value defined as a state requiring the maintenance.

14. The timing prediction system according to claim 13,

wherein the predictor is configured to calculate the approximate straight line or the approximate curve using at least two of the first parameters or the second parameters obtained at different time.

15. The timing prediction system according to claim 13,

wherein the calculator is configured to calculate a spring constant of the vibration tube as the first parameter,

wherein the predictor is configured to calculate a first approximate straight line or a first approximate curve showing a change with time of the first parameter or the second parameter related to the spring constant or a change of the first parameter or the second parameter related to the spring constant with respect to the integrated flow rate of the fluid, and

wherein the predictor is configured to calculate at least one of the time, the operating time, and the integrated flow rate of the fluid required for the first approximate straight line or the first approximate curve to reach a first threshold value which is related to the spring constant and defined as a state requiring the maintenance.

16. The timing prediction system according to claim 13,

wherein the calculator is configured to calculate a damping coefficient of the vibration tube as the first parameter,

wherein the predictor is configured to calculate a second approximate straight line or a second approximate curve showing a change with time of the first parameter or the second parameter related to the damping coefficient or a change of the first parameter or the second parameter related to the damping coefficient with respect to the integrated flow rate of the fluid, and

wherein the predictor is configured to calculate at least one of the time, the operating time, and the integrated flow rate of the fluid required for the second approximate straight line or the second approximate curve to reach a second threshold value which is related to the damping coefficient and defined as a state requiring the maintenance.

17. The timing prediction system according to claim 12, further comprising:

a disgnoser configured to diagnose a state of the vibration tube on the basis of the first parameter calculated by the calculator.

18. The timing prediction system according to claim 12,

wherein the calculation controller further comprises:

a measurer configured to measure the flow rate of the fluid flowing in the vibration tube on the basis of the second output signal output from the amplifier.

19. The timing prediction system according to claim 12,

wherein the calculator configured to calculate an entire mass of the vibration tube on the basis of the change ratio obtained by the change ratio obtainer and the constant oscillation feedback gain.

20. A timing prediction method using a Coriolis flowmeter which comprises a Coriolis sensor unit, a current amplifier, an amplifier, a smoother, a control amplifier, a voltage setter, a switch, a multiplier, and a calculation controller, the timing prediction method comprising:

detecting, by the Coriolis sensor unit, a vibration of a vibration tube to output a first output signal;

supplying, by the current amplifier, a drive current for vibrating the vibration tube to the Coriolis sensor unit;

amplifying, by the amplifier, the first output signal output from the Coriolis sensor unit to output a second output signal;

smoothing, by the smoother, the second output signal output from the amplifier to output a third output signal;

amplifying, by the control amplifier, a difference between the third output signal output from the smoother and a target voltage to output a fourth output signal;

outputting a fixed gain setting voltage by the voltage setter;

selecting, by the switch, one signal of the fourth output signal output from the control amplifier and the fixed gain setting voltage output from the voltage setter;

multiplying, by the multiplier, the second output signal output from the amplifier by the signal selected by the switch to output a fifth output signal to the current amplifier;

controlling the voltage setter and the switch by the calculation controller; and

amplifying, by the current amplifier, the fifth output signal output from the multiplier to generate the drive current,

wherein the calculation controller comprises a change ratio obtainer, a calculator, and a predictor, and

wherein the timing prediction method further comprises;

obtaining, by the change ratio obtainer, a change ratio of the vibration of the vibration tube when the vibration tube is vibrated with a constant driving force by causing the switch to select the fixed gain setting voltage;

calculating, by the calculator, a first parameter indicating at least one of a spring constant of the vibration tube and a damping coefficient of the vibration tube on the basis of the change ratio obtained by the change ratio obtainer and the constant driving force; and

predicting, by the predictor, at least one of a time, an operating time, and an integrated flow rate of a fluid flowing in the vibration tube required for a state of the vibration tube to become a state requiring maintenance, using the first parameter calculated by the calculator or a second parameter obtained by performing a predetermined calculation on the first parameter.