Device and method for detecting electrode leakage of electromagnetic flowmeter

Abstract

The present disclosure relates to a device and method for detecting electrode leakage of an electromagnetic flowmeter. According to one embodiment of the present disclosure, the device includes: a first and a second terminal, which are suitable for being electrically connected to the first and second electrodes of a flow sensor of an electromagnetic flowmeter; a signal generating unit, which is suitable for generating a periodic AC oscillation signal, and the signal generating unit is electrically connected to the first and second electrodes; an amplifier circuit, whose input end is electrically connected to the first node and the second node to amplify the signal from the first node and the second node; a signal detection circuit, which is electrically connected to the amplifier circuit and includes a common mode signal detection circuit, wherein the common mode signal detection circuit is suitable for detecting the common mode signal output by the amplifier circuit as a leakage detection signal; and a processor, which is suitable for determining whether an electrode leakage has occurred by comparing the characterization parameters of the leakage detection signal with the reference parameters. The device and method can conveniently detect electrode leakage of an electromagnetic flowmeter.

Description

Technical Field

[0001] The present disclosure relates generally to flow meters, and more particularly, to an apparatus and method for detecting electrode leakage of an electromagnetic flow meter. Background Art

[0002] As disclosed in CN105277240A, an electromagnetic flow meter is a common flow measurement device, which can measure the flow of a fluid such as sewage.

[0003] Due to electrode wear, lining wear and / or corrosion, improper installation of electrodes and linings, etc., fluid may leak at the junction of the electromagnetic flowmeter electrode and pipeline (also known as measuring tube). This leakage is called electrode leakage of the electromagnetic flowmeter.

[0004] The above leakage is undesirable. Therefore, there is a need in the art for a technology capable of detecting leakage of electrodes of an electromagnetic flowmeter. Summary of the invention

[0005] A brief overview of the disclosure will be given below in order to provide a basic understanding of certain aspects of the disclosure. It should be understood that this overview is not an exhaustive overview of the disclosure. It is not intended to identify key or important parts of the disclosure, nor is it intended to limit the scope of the disclosure. Its purpose is simply to give certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0006] According to one aspect of the present disclosure, there is provided a device for detecting electrode leakage of an electromagnetic flowmeter, comprising: a first terminal, which is suitable for being electrically connected to a first electrode of a flow sensor of the electromagnetic flowmeter; a second terminal, which is suitable for being electrically connected to a second electrode of the flow sensor of the electromagnetic flowmeter; a third terminal, which is suitable for being electrically connected to a sensor housing of the electromagnetic flowmeter; a signal generating unit, which is suitable for generating a periodic AC oscillation signal, the signal generating unit being electrically connected to the first electrode via a first resistor, a first node and a first terminal, and the signal generating unit being also electrically connected to the second electrode via a second resistor, a second node and a second terminal; an amplifier circuit, whose input end is electrically connected to the first node and the second node to amplify signals from the first node and the second node; a signal detection circuit, which is electrically connected to the amplifier circuit and comprises a common mode signal detection circuit, wherein the common mode signal detection circuit is suitable for detecting a common mode signal output by the amplifier circuit as a leakage detection signal; and a processor, which is suitable for determining whether an electrode leakage has occurred by comparing a characterization parameter of the leakage detection signal with a reference parameter.

[0007] According to another aspect of the present disclosure, a method for detecting electrode leakage of an electromagnetic flowmeter is provided, comprising using the aforementioned device to perform the following steps: applying a first signal to a first node and a second node by a signal generating unit under the following circumstances: a pipeline of the electromagnetic flowmeter is filled with a first fluid, and no electrode leakage occurs in the electromagnetic flowmeter; recording a characterization parameter of a leakage detection signal output by a common mode signal detection circuit as a reference parameter; applying a second signal identical to the first signal to the first node and the second node by the signal generating unit when the pipeline contains the first fluid; and determining whether an electrode leakage occurs by comparing the characterization parameter of the current leakage detection signal with the reference parameter.

[0008] With reference to the following description and accompanying drawings, the specific embodiments of the present disclosure are disclosed in detail, indicating the way in which the principles of the present disclosure can be adopted. It should be understood that the embodiments of the present disclosure are not limited in scope. Within the scope of the appended claims, the embodiments of the present disclosure include many changes, modifications and equivalents.

[0009] Where applicable, features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present disclosure may be better understood by referring to the following description given in conjunction with the accompanying drawings, which together with the following detailed description are included in this specification and form a part of this specification. In the drawings:

[0011] Figure 1a is a schematic diagram of a device for detecting electrode leakage of an electromagnetic flowmeter according to an embodiment of the present disclosure;

[0012] Figure 1b It is used to realize Figure 1a An exemplary circuit diagram of the device;

[0013] Figure 2 is a flow chart of a method for detecting electrode leakage of an electromagnetic flowmeter according to one embodiment of the present disclosure; and

[0014] Figure 3 yes Figure 1a Waveform diagram of the signal at the middle node n3 and the waveform diagram of the leakage detection signal. DETAILED DESCRIPTION

[0015] Exemplary embodiments of the present disclosure are described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual embodiments are described in the specification. However, it should be understood that many implementation-specific decisions can be made in the process of developing any such actual embodiments in order to achieve the specific goals of the developer, and these decisions may vary from embodiment to embodiment.

[0016] It is also necessary to explain here that, in order to avoid obscuring the present disclosure due to unnecessary details, only the device structure closely related to the scheme according to the present disclosure is shown in the drawings, while other details that are not closely related to the present disclosure are omitted.

[0017] Below, reference Figure 1a The basic structure of a device for detecting electrode leakage of an electromagnetic flowmeter according to an embodiment of the present disclosure is described.

[0018] Figure 1a 1 is a schematic diagram of a device 100 for detecting electrode leakage of an electromagnetic flowmeter according to an embodiment of the present disclosure. The device 100 includes: a first terminal 101a, which is suitable for being electrically connected to a first electrode (also referred to as Electrode-) 103a of a flow sensor of an electromagnetic flowmeter; a second terminal 101b, which is suitable for being electrically connected to a second electrode (also referred to as Electrode+) 103b of a flow sensor of an electromagnetic flowmeter; a third terminal 105, which is suitable for being electrically connected to a sensor housing 107 of an electromagnetic flowmeter; a signal generating unit 109, which is suitable for generating a periodic AC oscillation signal, the signal generating unit being electrically connected to the first electrode 103a via a first resistor R1, a first node n1 and the first terminal 101a, and the signal generating unit 109 is configured to generate a periodic AC oscillation signal. The generating unit 109 is also electrically connected to the second electrode 103b via the second resistor R2, the second node n2 and the second terminal 101b; an amplifier circuit 111, whose input end is electrically connected to the first node n1 and the second node n2 to amplify the signal from the first node n1 and the second node n2; a signal detection circuit 113, which is electrically connected to the amplifier circuit 111 and includes a common-mode signal detection circuit 113a, wherein the common-mode signal detection circuit 113a is suitable for detecting the common-mode signal output by the amplifier circuit as a leakage detection signal; and a processor 115, which is suitable for determining whether an electrode leakage has occurred by comparing the characterization parameters of the leakage detection signal with the reference parameters.

[0019] The device 100 can be used in an electromagnetic flowmeter, wherein the electromagnetic flowmeter includes a transmitter and a sensor. The first and second electrodes 103a, 103b and the sensor housing are components of the sensor, wherein the sensor housing corresponds to the housing of a pipeline of the flowmeter for accommodating fluid (i.e., a measuring tube of the electromagnetic flowmeter). When detecting a leak, the third terminal 105 is preferably grounded. The first and second resistors R1 and R2 preferably have equal resistance values.

[0020] The waveform of the periodic AC oscillation signal may be a triangular wave, a sine wave or a square wave. The peak-to-peak value of the periodic AC oscillation signal may range from 0.2 to 15 V, and the period of the periodic AC oscillation signal may range from 0.1 to 60 seconds. For example, the waveform is selected as a triangular wave, the peak-to-peak value is selected as 0.5 V, and the period of the triangular wave is selected as 2 seconds.

[0021] Determining whether an electrode leakage occurs by comparing the characteristic parameter of the leakage detection signal with the reference parameter includes: calculating the difference between the reference parameter and the characteristic parameter of the leakage detection signal, and if the absolute value of the difference is greater than a predetermined threshold, determining that an electrode leakage occurs. The determination of the reference parameter will be described in Figure 2 Provide instructions when necessary.

[0022] The device 100 may further include an analog-to-digital converter, whose input terminal is electrically connected to the common-mode signal detection circuit 113a, and whose output terminal is connected to the processor 115 via a bus. The analog-to-digital converter is suitable for converting the leakage detection signal into a first digital signal.

[0023] The signal detection circuit 113 may further include a differential signal detection circuit 113b, and the differential signal detection circuit 113b is suitable for detecting the differential signal output by the amplification circuit 111 as a flow signal.

[0024] Preferably, the analog-to-digital converter is a dual-channel analog-to-digital converter, which is also electrically connected to the differential signal detection circuit 113b and is suitable for converting the flow signal into a second digital signal.

[0025] Preferably, the device 100 further comprises: a storage unit, wherein the storage unit is connected to the processor 115 via a bus, and the storage unit is configured to store the first digital signal and the second digital signal. The storage unit can also store more types of data, such as: reference parameters, characterization parameters of the leak detection signal, and characterization parameters of the flow signal.

[0026] Preferably, the processor 115 is further configured to: execute a display routine to display a prompt message and / or execute an alarm routine to sound an alarm when it is determined that an electrode leakage has occurred. That is, a display device and / or an alarm device may also be connected to the bus. The alarm device may emit an audible and / or optical alarm signal.

[0027] When using the flow meter, when a periodic AC oscillation signal is applied to nodes n1 and n2, compared with the case where electrode leakage does not occur, after electrode leakage occurs, due to the conduction of the fluid, the impedance of the first and second electrodes 103a and 103b to the ground changes, thereby changing the potential at the first node n1 and the second node n2. Therefore, by extracting the potential at the first node n1 and the second node n2 and comparing them with the potential when no leakage occurs, it is possible to determine whether electrode leakage occurs.

[0028] For example, the analog-to-digital converter is electrically connected to the common-mode signal detection circuit 113a and is used to convert the leakage detection signal into a first digital signal. The processor 115 receives the first digital signal and stores it in a storage unit; during leakage detection, the processor 115 reads the data of the first digital signal when no leakage occurs and the data of the current first digital signal, and calculates the characterization parameters of the two data (such as the peak-to-peak value of the digital signal waveform): the reference parameter V0, the current characterization parameter Vt; the threshold ΔV can be set based on experience th , when the processor 115 determines that the absolute value of the difference between the reference parameter V0 and the current characterization parameter Vt is greater than the threshold ΔV th When V0 is equal to Vt, the processor 115 outputs an output signal indicating that electrode leakage has occurred, otherwise it outputs an output signal indicating that electrode leakage has not occurred. As a variation, the processor 115 can output data representing the degree of electrode leakage of the electromagnetic flowmeter according to the absolute value of the difference between V0 and Vt.

[0029] It should be noted that, compared with the leakage detection signal when no electrode leakage occurs, when electrode leakage occurs, the leakage detection signal at this time is related to the degree of leakage and the conductivity of the fluid.

[0030] Figure 1b It is used to realize Figure 1a An exemplary circuit diagram of the device in FIG.

[0031] Figure 1b The device includes: a first electrode 103a, a second electrode 103b, an anti-interference circuit 119, a signal generating unit 109', an amplifier circuit 111', a differential signal detection circuit 113b', a common signal detection circuit 113a', an analog-to-digital converter 117, and a CPU 115'. Figure 1bAs shown in , the common-mode signal detection circuit 113a' includes two parts: a left part (used to realize signal amplification, including OA5) and a right part (lifting circuit, including: OA4 and ADR381ARTZ). The first electrode 103a is electrically connected to the first node n1 via the anti-interference circuit 119, and the second electrode 103b is electrically connected to the second node n2 via the anti-interference circuit 119. The anti-interference circuit 119 resists on-site interference to prevent interference signals from entering subsequent circuits and causing malfunctions. The signal generating unit 109' generates a periodic AC oscillation signal, which is simultaneously applied to the first node n1 and the second node n2 through two resistors R1 and R2. The lifting circuit can superimpose a voltage (e.g., 2.5V) equal to half the reference voltage (e.g., 5V) of the analog-to-digital converter 117 on the common-mode signal voltage, and it has a high output impedance characteristic. As shown Figure 1b As shown, the common-mode signal is output to the analog-to-digital converter 117 via the operational amplifier OA5. At the same time, the negative terminal of the operational amplifier OA5 is connected to a voltage half of the reference voltage of the analog-to-digital converter 117. The differential-mode signal detection circuit 113b' is used to extract the differential-mode signal as a flow signal. The common-mode signal detection circuit 113a' is used to extract the leakage detection signal. The analog-to-digital converter 117 is a dual-channel analog-to-digital converter that converts analog input into digital output (i.e., outputs a first digital signal and a second digital signal). The CPU 115' can calculate the flow rate based on the digitized flow signal; it can also determine whether the electromagnetic flowmeter has leaked based on the digitized leakage detection signal. If it is determined that the electromagnetic flowmeter has leaked, an indication can be issued to issue an alarm.

[0032] exist Figure 1b Middle: The signal generating unit 109' can realize Figure 1a The signal generating unit 109 in the embodiment of the present invention comprises a signal output control terminal MT_ON, the output control terminal MT_ON is electrically connected to the inverting input terminal and the output terminal of the operational amplifier OA1 of the signal generating unit, so as to control whether the signal generating unit outputs a periodic AC oscillation signal, that is, whether an oscillation signal is input to the first resistor R1 and the second resistor R2 by inputting a control signal from the output control terminal; the signal generating unit 109' further comprises a signal waveform control terminal MT_PWM, which inputs a modulation signal to generate a periodic AC oscillation signal; the common mode signal detection circuit 113a' is used to implement Figure 1a The common mode signal detection circuit 113a in the differential mode signal detection circuit 113b' is used to realize Figure 1a The differential signal detection circuit 113b in the CPU 115' is used to implement Figure 1a The processor 115 in.

[0033] Figure 22 is a flow chart of a method 200 for detecting electrode leakage of an electromagnetic flowmeter according to an embodiment of the present disclosure. The method 200 uses the aforementioned device for detecting electrode leakage of an electromagnetic flowmeter (such as the device 100) to perform the following steps.

[0034] At step 201 , a first signal is applied to a first node and a second node by a signal generating unit in the following cases: a pipe of an electromagnetic flowmeter is filled with a first fluid, and it is determined that no electromagnetic flowmeter electrode leakage occurs in the electromagnetic flowmeter.

[0035] At step 203, the characteristic parameters of the leakage detection signal output by the common mode signal detection circuit are recorded as reference parameters. The recording may be specifically implemented by storing the digitized characteristic parameters of the leakage detection signal in a storage unit.

[0036] At step 205 , when the pipeline contains the first fluid, a second signal identical to the first signal is applied to the first node and the second node by a signal generating unit.

[0037] At step 207, by comparing the characteristic parameters of the current leakage detection signal with the reference parameters, it is determined whether leakage occurs in the electromagnetic flowmeter electrode.

[0038] The fluid flow rate when determining the reference parameter is preferably close to or equal to the fluid flow rate when applying the second signal; further, the flow rates can be selected to be zero.

[0039] Optionally, the method 200 may further include: after determining that electrode leakage has occurred, issuing an alarm, displaying prompt information, sending prompt information to a user, or storing information related to the electromagnetic flowmeter electrode leakage.

[0040] Figure 3 yes Figure 1a The waveform diagram of the leakage detection signal at the node n3, where the horizontal axis is time and the vertical axis is amplitude. When executing method 200, it can be obtained Figure 3 The waveforms shown in FIG. 301 are the waveforms of the electrical signal at the node n3; the curve 303 is the waveform of the leakage detection signal when no electrode leakage occurs; and the curve 305 is the waveform of the leakage detection signal when electrode leakage occurs. It can be seen that the curves 303 and 305 are different in amplitude and waveform.

[0041] The above-mentioned device and method for detecting electrode leakage of an electromagnetic flowmeter can conveniently detect electrode leakage of an electromagnetic flowmeter without adding electrodes to the pipeline of the electromagnetic flowmeter, affecting flow measurement, and generating no polarization effect.

[0042] Although the present disclosure has been disclosed above by describing the specific embodiments of the present disclosure, it should be understood that those skilled in the art may design various modifications, improvements or equivalents of the present disclosure within the spirit and scope of the appended claims. These modifications, improvements or equivalents should also be considered to be included in the protection scope of the present disclosure.

[0043] It should be emphasized that the term "include / comprise" when used herein refers to the presence of a feature, element or component, but does not exclude the presence or addition of one or more other features, elements or components. The terms "first" or "second" and the like related to ordinal numbers do not indicate the order of implementation or the degree of importance of the features, elements or components defined by these terms, but are merely used to identify between these features, elements or components for the sake of clarity of description.

Claims

1. A device for detecting electrode leakage of an electromagnetic flowmeter, comprising: A first terminal, which is suitable for being electrically connected to a first electrode of a flow sensor of the electromagnetic flowmeter; A second terminal, which is suitable for being electrically connected to a second electrode of the flow sensor of the electromagnetic flowmeter; A third terminal, which is suitable for being electrically connected to a sensor housing of the electromagnetic flowmeter; a signal generating unit, adapted to generate a periodic AC oscillation signal for generating a leakage detection signal, the signal generating unit being electrically connected such that: the periodic AC oscillation signal is applied to the first electrode via a first path including a third node, a first resistor, a first node and the first terminal connected in sequence, and the periodic AC oscillation signal is also applied to the second electrode via a second path including the third node, a second resistor, a second node and the second terminal connected in sequence, and neither the first path nor the second path includes a capacitor; an amplifier circuit, whose input terminal is electrically connected to the first node and the second node to amplify signals from the first node and the second node; a signal detection circuit, which is electrically connected to the amplifying circuit and comprises a common-mode signal detection circuit, wherein the common-mode signal detection circuit is adapted to detect a common-mode signal output by the amplifying circuit as the leakage detection signal; as well as A processor is adapted to determine whether the electrode leaks by comparing a characteristic parameter of the leak detection signal with a reference parameter.

2. The device according to claim 1, wherein: The waveform of the periodic AC oscillation signal is a triangle wave, a sine wave or a square wave, the peak-to-peak value of the periodic AC oscillation signal ranges from 0.2 to 15 V, and the period of the periodic AC oscillation signal ranges from 0.1 to 60 seconds.

3. The device according to claim 1, wherein: The signal generating unit comprises an output control terminal, and the output control terminal is electrically connected to the inverting input terminal and the output terminal of the operational amplifier of the signal generating unit, so as to control whether the signal generating unit outputs the periodic AC oscillation signal by inputting a control signal from the output control terminal.

4. The device according to claim 1, wherein: Determining whether the electrode leakage occurs by comparing the characteristic parameter of the leakage detection signal with a reference parameter includes: calculating the difference between the reference parameter and the characteristic parameter of the leakage detection signal, and determining that the electrode leakage occurs if the absolute value of the difference is greater than a predetermined threshold.

5. The apparatus according to claim 1, further comprising: An analog-to-digital converter, whose input end is electrically connected to the common-mode signal detection circuit, whose output end is connected to the processor via a bus, is suitable for converting the leakage detection signal into a first digital signal.

6. The device according to claim 5, wherein: The signal detection circuit further comprises a differential mode signal detection circuit, and the differential mode signal detection circuit is suitable for detecting the differential mode signal output by the amplification circuit as a flow signal.

7. The device according to claim 6, wherein: The analog-to-digital converter is a dual-channel analog-to-digital converter, which is also electrically connected to the differential signal detection circuit and is suitable for converting the flow signal into a second digital signal.

8. The apparatus according to claim 7, further comprising: A storage unit, wherein the storage unit is connected to the processor via the bus, and the storage unit is configured to store the first digital signal and the second digital signal.

9. The device according to claim 1, wherein the processor is further configured to: execute a display routine to display a prompt message and / or execute an alarm routine to sound an alarm after determining that the electrode leakage occurs.

10. A method for detecting electrode leakage of an electromagnetic flowmeter, comprising using the device according to any one of claims 1 to 9 to perform the following steps: In the following cases, the signal generating unit applies the first signal to the first node and the second node: the pipeline of the electromagnetic flowmeter is filled with the first fluid, and the electromagnetic flowmeter does not have the electrode leakage; Recording the characteristic parameters of the leakage detection signal output by the common mode signal detection circuit as reference parameters; In a case where the pipeline contains the first fluid, the signal generating unit applies a second signal identical to the first signal to the first node and the second node; and By comparing the characteristic parameter of the current leakage detection signal with the reference parameter, it is determined whether the electrode leakage occurs.

11. The method according to claim 10, further comprising: After determining that the electromagnetic flowmeter electrode is leaking, an alarm is issued, prompt information is displayed, and / or information related to the electrode leakage is stored.

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