Coriolis flowmeter, timing prediction system, and timing prediction method

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 either the fourth output signal or the fixed gain setting voltage;
• a multiplier configured to multiply the second output signal output from the amplifier by the fourth signal or the fixed gain setting voltage selected by the switch to output a fifth output signal to the current amplifier;
• and
• a first hardware processor 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 first hardware processor is configured to:
• obtain a growth ratio of an integral value of a square value of an output value from the Coriolis sensor unit when the switch is caused to select a first gain;
• obtain an attenuation ratio of the integral value of the square value of the output value from the Coriolis sensor unit when the switch is caused to select a second gain which is smaller than the first gain;
• and
• 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 growth ratio, the attenuation ratio, the first gain, and the second gain,
• wherein the calculation device comprises a second hardware processor configured to:
• predict a time required for a state of the vibration tube to become a state requiring maintenance, using the first parameter or a second parameter obtained by performing a predetermined calculation on the first parameter.

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 hardware processor, 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, either the fourth output signal or the fixed gain setting voltage;
• multiplying, by the multiplier, the second output signal output from the amplifier by the fourth signal or the fixed gain setting voltage selected by the switch to output a fifth output signal to the current amplifier;
• controlling the voltage setter and the switch by the hardware processor;
• amplifying, by the current amplifier, the fifth output signal output from the multiplier to generate the drive current;
• obtaining, by the hardware processor, a growth ratio of an integral value of a square value of an output value from the Coriolis sensor unit when the switch is caused to select a gain;
• obtaining, by the hardware processor, an attenuation ratio of the integral value of the square value of the output value from the Coriolis sensor unit when the switch is caused to select a second gain which is smaller than the first gain;
• calculating, by the hardware processor, 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 growth ratio, the attenuation ratio, the first gain, and the second gain;
• and
• predicting, by the hardware processor, a time required for a state of the vibration tube to become a state requiring maintenance, using the first parameter or a second parameter obtained by performing a predetermined calculation on the first parameter.