Vortex flow meter and method for testing a vortex flow meter

Patent metadata

Field	Value
Publication number	US-12306025-B2
Application number	US-202118258029-A
Country	US
Kind code	B2
Filing date	Nov 26, 2021
Priority date	Dec 17, 2020
Publication date	May 20, 2025
Grant date	May 20, 2025

Abstract

A vortex flow meter comprises a measuring tube; a bluff body arranged in the measuring tube; a sensor device, having a paddle, a sensor main body and a piezo element, and an electronic operating circuit. The electronic operating circuit has a measuring circuit comprising an operational amplifier and a capacitor. The first capacitor forms a feedback between the output and the measurement input, wherein the reference input can be supplied with a first reference voltage. The measurement circuit has a first switch, wherein the electronic operating circuit is designed to connect the piezo element via the first switch to the measurement input of the operational amplifier and to charge it with a first charging voltage by means of a second switch position. The electronic operating circuit derives an information relating to a state of the piezo element from a discharge process of the piezo element.

First claim

The invention claimed is:

1. A vortex flow meter for measuring a flow of medium flowing through a pipeline, comprising:
a measuring tube for guiding the medium with a measuring tube wall and a measuring tube lumen formed by the measuring tube wall, wherein the measuring tube wall has an opening;
a bluff body arranged in the measuring tube;
a sensor device designed to detect flow vortices caused by the bluff body, the sensor device including a paddle, a sensor main body, and a piezo element, wherein the sensor main body is arranged in the opening and seals media-tight with the measuring tube wall, wherein the paddle projects into the measuring tube lumen and is designed to be deflected by flow vortices from a force-free resting position, and wherein the piezo element is arranged on a rear side of the sensor main body facing away from the measuring tube and is designed to detect deformations of the sensor main body caused by deflections of the paddle and to convert the deformations into an electrical measurement signal; and
an electronic operating circuit designed to detect and evaluate the measurement signal via an evaluation circuit and to provide flow measurement values,
wherein the electronic operating circuit includes a measuring circuit including an operational amplifier having an inverting input, a non-inverting input and an output, and further includes a first capacitor,
wherein the first capacitor forms a feedback between the output and the inverting input or the non-inverting input, wherein the respective input is a measurement input,
wherein the respective other input is a reference input and can be supplied with a first reference voltage, and wherein the output is connected to the evaluation circuit of the electronic operating circuit,
wherein the piezo element can be supplied with a second reference voltage on a side facing away from the operational amplifier, which is equal to the first reference voltage,
wherein the measuring circuit further includes a first switch having a first position and a second position,

wherein the electronic operating circuit is designed to connect the piezo element via the first position of the first switch to the measurement input of the operational amplifier and to charge the piezo element with a first charging voltage via the second position of the first switch, and
wherein the electronic operating circuit is further designed to derive via the evaluation circuit from a discharge process of the piezo element an information relating to a state of the piezo element, and/or an electrical connection of the piezo element to the electronic operating circuit, and/or a mechanical connection to the sensor main body.

2. The vortex flow meter according to claim 1 ,
wherein the measuring circuit further includes a second capacitor and a second switch, the second switch having a first position and a second position,
wherein the second capacitor can be supplied with the second reference voltage,
wherein the electronic operating circuit is further designed to connect the second capacitor via the first position of the second switch to the measurement input of the operational amplifier and to charge the second capacitor with a second charging voltage via the second position of the second switch,
wherein the first charging voltage and the second reference voltage define a first differential voltage, and wherein the second charging voltage and the second reference voltage define a second differential voltage,
wherein the second differential voltage has a polarity opposite to the first differential voltage, and
wherein the second capacitor and the piezo element can be connected in parallel via the respective first position of the first and second switches.

3. The vortex flow meter according to claim 2 ,
wherein the electronic operating circuit is designed to charge the piezo element with a first charge and the second capacitor with a second charge with respect to the second reference voltage,
wherein an amount of the first charge and an amount of the second charge deviates less than 10% from an average value of the charges.

4. The vortex flow meter according to claim 3 ,
wherein the operational amplifier has an input voltage range with a first limit value and a second limit value and an average value, wherein the first reference voltage deviates from the average value by less than 10%.

5. The vortex flow meter according to claim 4 ,
wherein the piezo element has a maximum capacitance, wherein the second capacitor has a nominal capacitance,
wherein the nominal capacitance of the second capacitor is at least 5% greater than the maximum capacitance of the piezo element.

6. A method for testing a piezo element of a vortex flow meter, the method comprising:
providing the vortex flow meter, including:
a measuring tube for guiding the medium with a measuring tube wall and a measuring tube lumen formed by the measuring tube wall, wherein the measuring tube wall has an opening;
a bluff body arranged in the measuring tube;
a sensor device designed to detect flow vortices caused by the bluff body, the sensor device including a paddle, a sensor main body, and a piezo element, wherein the sensor main body is arranged in the opening and seals media-tight with the measuring tube wall, wherein the paddle projects into the measuring tube lumen and is designed to be deflected by flow vortices from a force-free resting position, and wherein the piezo element is arranged on a rear side of the sensor main body facing away from the measuring tube and is designed to detect deformations of the sensor main body caused by deflections of the paddle and to convert the deformations into an electrical measurement signal; and
an electronic operating circuit designed to detect and evaluate the measurement signal via an evaluation circuit and to provide flow measurement values,
wherein the electronic operating circuit includes a measuring circuit including an operational amplifier having an inverting input, a non-inverting input and an output, and further includes a first capacitor,
wherein the first capacitor forms a feedback between the output and the inverting input or the non-inverting input, wherein the respective input is a measurement input,
wherein the respective other input is a reference input and can be supplied with a first reference voltage, and wherein the output is connected to the evaluation circuit of the electronic operating circuit,
wherein the piezo element can be supplied with a second reference voltage on a side facing away from the operational amplifier, which is equal to the first reference voltage,
wherein the measuring circuit further includes a first switch having a first position and a second position,

wherein the electronic operating circuit is designed to connect the piezo element via the first position of the first switch to the measurement input of the operational amplifier and to charge the piezo element with a first charging voltage via the second position of the first switch, and
wherein the electronic operating circuit is further designed to derive via the evaluation circuit from a discharge process of the piezo element an information relating to a state of the piezo element, and/or an electrical connection of the piezo element to the electronic operating circuit, and/or a mechanical connection to the sensor main body;

switching the first switch from its first position to its second position to charge the piezo element;
switching the first switch to its first position after charging the piezo element to discharge the piezo element; and
detecting the discharge process via the electronic operating circuit and deriving an information relating to a state of the piezo element and/or an electrical connection of the piezo element from

Assignees

• Flowtec Ag

Inventors

• Schirmeier Timo
• Tanner Werner
• Schweizer Dieter

Classifications

• G01F1/3287

  circuits therefor · CPC title

• G01F25/00

  Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume · CPC title

• G01F1/3209

  using Karman vortices · CPC title

• G01F1/3218 Primary

  bluff body design · CPC title

• G01F1/3266 Primary

  by sensing mechanical vibrations · CPC title