Diagnostic system

Abstract

To provide a diagnostic system capable of improving accuracy in estimating a deterioration degree of a valve element and a valve seat of a valve.SOLUTION: The diagnostic system includes an acoustic sensor 21 that detects sound generated in the valve body 5 and the valve seat 3 of the gate valve 1, and a diagnostic device 23 that diagnoses the deterioration states of the valve body 5 and the valve seat 3 using a detection signal of the acoustic sensor 21. The diagnostic device 23 extracts the time range set corresponding to the movement of the valve body 5 from the detection signal of the acoustic sensor 21 to extract the sliding sound of the valve body 5 sliding on the valve seat 3, and analyzes the sliding sound to estimate the degree of deterioration of the valve body 5 and the valve seat 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a diagnostic system for diagnosing the deterioration state of a valve disc and a valve seat of a valve. [Background technology]

[0002] A valve has the function of shutting off the flow of fluid by contacting the valve disc with the valve seat. However, because the valve disc slides on the valve seat, the valve disc and valve seat can wear and deteriorate with increasing number of operations or operating time, which can impair the above-mentioned function.

[0003] Patent Document 1 discloses a diagnostic system for diagnosing the deterioration state of a valve disc and valve seat. The diagnostic system in Patent Document 1 includes a first acoustic sensor that detects sounds generated in the valve disc and valve seat, a second acoustic sensor that detects sounds generated in other parts of the valve (more specifically, the valve stem connected to the valve disc and the drive unit that moves the valve disc via the valve stem), and a diagnostic device that diagnoses the deterioration state of the valve disc and valve seat using the detection signals of the first and second acoustic sensors.

[0004] The first acoustic sensor detects not only sounds generated by the valve disc and valve seat, but also sounds generated by other components. Therefore, the diagnostic device extracts the sliding sound of the valve disc sliding on the valve seat by subtracting the detection signal of the second acoustic sensor multiplied by the sound propagation coefficient (more specifically, the sound attenuation rate between the second acoustic sensor and the first acoustic sensor) from the detection signal of the first acoustic sensor. The extracted sliding sound is then analyzed to estimate the degree of deterioration of the valve disc and valve seat (more specifically, surface roughness, etc.). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-115776 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, the sound attenuation rate between the second acoustic sensor and the first acoustic sensor is required. If the accuracy of the sound attenuation rate is low, the accuracy of extracting the sliding sound of the valve disc sliding on the valve seat will also be low. As a result, the accuracy of estimating the deterioration degree of the valve disc and valve seat will also be low.

[0007] An object of the present invention is to provide a diagnostic system that can improve the accuracy of estimating the degree of deterioration of a valve disc and a valve seat of a valve. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides a diagnostic system including an acoustic sensor that detects sounds generated at a valve disc and a valve seat of a valve, and a diagnostic device that diagnoses the deterioration state of the valve disc and the valve seat using the detection signal of the acoustic sensor. The diagnostic device extracts a time range set corresponding to the movement of the valve disc from the detection signal of the acoustic sensor, thereby extracting the sliding sound of the valve disc sliding on the valve seat, and analyzes the sliding sound to estimate the degree of deterioration of the valve disc and the valve seat. [Effects of the Invention]

[0009] According to the present invention, it is possible to improve the accuracy of estimating the degree of deterioration of the valve disc and valve seat of a valve. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram illustrating a configuration of a diagnostic system according to an embodiment of the present invention. [Figure 2] 1 is a diagram showing the structure of a gate valve to be diagnosed in one embodiment of the present invention, together with the arrangement of acoustic sensors. [Figure 3] 10A and 10B are diagrams showing specific examples of detection signals of an acoustic sensor according to an embodiment of the present invention, together with specific examples of detection signals of a displacement sensor. [Figure 4] FIG. 10 is a diagram showing a specific example of a frequency distribution that is an analysis result of sliding noise in one embodiment of the present invention. [Figure 5]FIG. 10 is a diagram illustrating a calculation table showing the relationship between the rate of change in frequency distribution and the degree of deterioration of the valve body and the valve seat in one embodiment of the present invention. [Figure 6] FIG. 10 is a diagram illustrating a calculation table showing the relationship between the deterioration level of the valve body and the valve seat and the risk of leakage in one embodiment of the present invention. [Figure 7] FIG. 4 is a diagram illustrating a calculation table showing the relationship between the degree of deterioration of the valve body and the valve seat and the number of operations or the operating time in one embodiment of the present invention. [Figure 8] 10A and 10B are diagrams showing specific examples of detection signals of an acoustic sensor in a first modified example of the present invention, together with specific examples of signals generated in association with driving of a motor. [Figure 9] FIG. 10 is a diagram showing a specific example of a fractal distribution that is an analysis result of sliding noise in the second modified example of the present invention. [Figure 10] FIG. 10 is a diagram showing the structure of a globe valve to be diagnosed in a third modified example of the present invention, together with the arrangement of acoustic sensors. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the present invention will be described with reference to the drawings.

[0012] Fig. 1 is a block diagram showing the configuration of a diagnostic system according to this embodiment. Fig. 2 is a diagram showing the structure of a gate valve to be diagnosed according to this embodiment, together with the arrangement of acoustic sensors.

[0013] First, we will explain the gate valve 1 to be diagnosed. The gate valve 1 comprises a casing 4 having a flow path 2 and a valve seat 3, a valve element 5 arranged inside the casing 4 and capable of closing the flow path 2 by abutting against the valve seat 3, a valve stem 6 connected to the valve element 5 and passing through the casing 4, a gland packing 7 arranged inside the casing 4 and supporting the valve stem 6 so that it can slide, and a drive unit 8 arranged outside the casing 4 and moving the valve element 5 via the valve stem 6.

[0014] The drive unit 8 includes a worm 9, a worm wheel 10 having external teeth (not shown) that mesh with the male thread portion 9a of the worm 9 and internal teeth (not shown) that mesh with the male thread portion 6a of the valve stem 6, a motor 11 connected to the worm 9 via a gear (not shown), and a handle 12 connected to the worm 9 via a gear (not shown).

[0015] The worm 9 is rotated by driving a motor 11 or by manually operating a handle 12. The rotation of the worm 9 is converted into the movement of the valve stem 6 via a worm wheel 10, which moves the valve disc 5 in the vertical direction in Figure 2. When the valve disc 5 moves to the upper side of Figure 2 and separates from the valve seat 3, the flow path 2 is opened, and when the valve disc 5 moves to the lower side of Figure 2 and abuts against the valve seat 3, the flow path 2 is closed. When diagnosing the gate valve 1, it is preferable not to let fluid flow through the flow path 2 and to prevent flow noise.

[0016] The diagnostic system of this embodiment includes an acoustic sensor 21 arranged, for example, at the bottom of the casing 4 of the check valve 1 (i.e., near the valve seat 3), a displacement sensor 22 that detects the displacement of the valve stem 6 connected to the valve body 5 (more specifically, the position of the valve stem 6 in the vertical direction in Figure 2), and a diagnostic device 23 that diagnoses the deterioration state of the valve body 5 and the valve seat 3 using the detection signals of the acoustic sensor 21 and the displacement sensor 22.

[0017] The acoustic sensor 21 is an acoustic emission sensor that detects sound generated at the valve disc 5 and valve seat 3 of the gate valve 1 as acoustic emission (elastic waves). Alternatively, the acoustic sensor 21 is a piezoelectric sensor, a vibration sensor, or an ultrasonic sensor. The acoustic sensor 21 is held by an operator or installed using a jig (not shown). The jig is fixed to the gate valve 1 by a band, magnet, adhesive, welding, or solder, or is fixed to the ground by an arm or tripod. Note that a couplant 24 (more specifically, an acoustic transmission medium such as grease, wax, adhesive, lubricating oil, water, or gel) is disposed between the acoustic sensor 21 and the surface of the casing 4.

[0018] The diagnostic device 23 includes a signal processing unit 25 that processes the detection signal of the acoustic sensor 21, a sliding sound extraction unit 26 that extracts the sliding sound of the valve disc 5 sliding against the valve seat 3 from the detection signal of the acoustic sensor 21 processed by the signal processing unit 25, a sliding sound analysis unit 27 that analyzes the sliding sound extracted by the sliding sound extraction unit 26, an abnormality determination unit 28 that determines whether the valve disc 5 and the valve seat 3 are abnormal based on the analysis results of the sliding sound analysis unit 27, a deterioration degree estimation unit 29 that estimates the degree of deterioration (more specifically, surface roughness, etc.) of the valve disc 5 and the valve seat 3 based on the analysis results of the sliding sound analysis unit 27, and a maintenance timing estimation unit 30 that estimates the maintenance timing of the check valve 1 based on the deterioration degrees of the valve disc 5 and the valve seat 3.

[0019] The signal processing unit 25 is composed of, for example, an amplifier 31 that amplifies the detection signal of the acoustic sensor 21 to a predetermined level, a filter 32 (more specifically, a band-pass filter, high-pass filter, or low-pass filter) that passes specific frequency components in the detection signal processed by the amplifier 31 and cuts out other frequency components, and an A / D converter 33 that digitally converts the detection signal processed by the filter 32.

[0020] The sliding sound extraction unit 26, sliding sound analysis unit 27, abnormality determination unit 28, deterioration level estimation unit 29, and maintenance timing estimation unit 30 are each composed of a processor (not shown) that executes processing according to a program, a memory (not shown) that stores the program and data, and the like.

[0021] The sliding sound extraction unit 26 extracts the sliding sound of the valve disc 5 sliding on the valve seat 3 by extracting a time range set corresponding to the displacement of the valve stem 6 detected by the displacement sensor 22 from the detection signal of the acoustic sensor 21 processed by the signal processing unit 25. The details will be explained using Fig. 3. Fig. 3 is a diagram showing a specific example of the detection signal of the acoustic sensor in this embodiment, together with a specific example of the detection signal of the displacement sensor.

[0022] The detection signal of the displacement sensor 22 in Figure 3 shows a case where the valve stem 6 and valve disc 5 move downward in Figure 2 in response to manual operation of the handle 12. From time t1 to time t2, the valve stem 6 and valve disc 5 move downward in response to manual operation of the handle 12, and from time t2 to time t3, the valve disc 5 is in contact with the valve seat 3. Then, from time t3 to time t4, the valve stem 6 and valve disc 5 move further downward in response to manual operation of the handle 12, that is, the valve disc 5 is pushed into the valve seat 3 and slides.

[0023] 3, the sudden waveform at time t1 is the sound generated at the handle 12. The small waveform between time t1 and time t2 is the sound generated at the worm 9, the worm wheel 10, or the valve stem 6. The sudden waveform between time t3 and time t4 is the sliding sound of the valve disc 5 sliding on the valve seat 3. The sliding sound extraction unit 26 extracts the sliding sound of the valve disc 5 sliding on the valve seat 3 by extracting the range from time t3 to time t4 from the detection signal of the acoustic sensor 21, which corresponds to the displacement of the valve stem 6 detected by the displacement sensor 22 (more specifically, the range from preset position Pa to position Pb).

[0024] The sliding sound analysis unit 27 performs, for example, frequency analysis on the sliding sound extracted by the sliding sound extraction unit 26, and acquires a frequency distribution as shown in Fig. 4. The sliding sound analysis unit 27 stores the initial frequency distribution as shown in Fig. 4 (in other words, before the valve disc 5 and the valve seat 3 deteriorated), and compares the current frequency distribution acquired as described above with the initial frequency distribution to calculate the rate of change in the frequency distribution.

[0025] The abnormality determination unit 28 determines whether the valve element 5 and the valve seat 3 are abnormal based on whether the rate of change in the frequency distribution calculated by the sliding sound analysis unit 27 is equal to or greater than a predetermined threshold value, and then displays the determination result on a display (not shown).

[0026] The deterioration level estimation unit 29 stores, for example, a calculation table (see FIG. 5) showing the relationship between the rate of change in frequency distribution and the deterioration level of the valve disc 5 and the valve seat 3, and uses this calculation table to calculate the deterioration level of the valve disc 5 and the valve seat 3 corresponding to the rate of change in frequency distribution calculated by the sliding sound analysis unit 27. Then, the calculated deterioration level is displayed on a display.

[0027] The maintenance timing estimation unit 30 stores, for example, a calculation table (see FIG. 6 ) showing the relationship between the deterioration level of the valve disc 5 and the valve seat 3 and the leakage risk, and uses this calculation table to calculate the deterioration level of the valve disc 5 and the valve seat 3 for which maintenance should be performed, corresponding to the leakage risk for which maintenance should be performed. The maintenance timing estimation unit 30 also stores, for example, a calculation table (see FIG. 7 ) showing the relationship between the deterioration level of the valve disc 5 and the valve seat 3 and the number of operations or the operating time, and uses this calculation table to calculate the number of operations or the operating time for which maintenance should be performed, corresponding to the deterioration level of the valve disc 5 and the valve seat 3 for which maintenance should be performed, or the current number of operations or the operating time (however, this is not the actual number of operations but takes the degree of deterioration into consideration) corresponding to the deterioration level of the valve disc 5 and the valve seat 3 calculated by the deterioration level estimation unit 29. Then, the maintenance timing is calculated as the difference between the number of operations of the former and the number of operations of the latter, or the difference between the operating time of the former and the operating time of the latter. The calculated maintenance timing is then displayed on a display.

[0028] According to the diagnostic system of this embodiment, the deterioration state of the valve disc 5 and valve seat 3 of the gate valve 1 can be diagnosed without disassembling the gate valve 1. Furthermore, in the diagnostic system of this embodiment, as described above, the sliding sound of the valve disc 5 sliding on the valve seat 3 is extracted by extracting a time range set corresponding to the displacement of the valve stem 6 detected by the displacement sensor 22 from the detection signal of the acoustic sensor 21. Therefore, unlike Patent Document 1, there is no need to install multiple acoustic sensors. Furthermore, the extraction accuracy is improved compared to when the sliding sound of the valve disc 5 sliding on the valve seat 3 is extracted using the sound attenuation rate between multiple acoustic sensors. As a result, the accuracy of estimating the deterioration degree of the valve disc 5 and valve seat 3 is also improved.

[0029] In the above embodiment, the sliding sound extraction unit 26 of the diagnostic device 23 extracts the sliding sound of the valve disc 5 sliding on the valve seat 3 by extracting a time range set corresponding to the displacement of the valve stem 6 detected by the displacement sensor 22 from the detection signal of the acoustic sensor 21, but this is not limiting. That is, the sliding sound extraction unit 26 of the diagnostic device 23 may extract the sliding sound of the valve disc 5 sliding on the valve seat 3 by extracting a time range set corresponding to the movement of the valve disc 5 from the detection signal of the acoustic sensor 21. A first modified example will now be described.

[0030] The diagnostic system of the first modified example includes a sensor (not shown, for example, an acoustic sensor that detects sounds generated by the motor 11, or a current sensor that detects the current that drives the motor 11) that detects signals generated as the motor 11 is driven, instead of the displacement sensor 22. A sliding sound extraction unit 26 of the diagnostic device 23 extracts the sliding sound of the valve disc 5 sliding on the valve seat 3 from the detection signal of the acoustic sensor 21 within a time range set in accordance with the drive of the motor 11. Details of this will be explained using FIG. 8. FIG. 8 is a diagram showing a specific example of a detection signal of the acoustic sensor in this modified example, together with a specific example of a signal generated as the motor is driven.

[0031] The signal generated in association with the driving of the motor in Fig. 8 shows the case where the valve stem 6 and valve disc 5 move downward in Fig. 2 in response to the driving of the motor 11. The motor 11 is driven in the time range (Δt1 + Δt2), and the valve disc 5 slides against the valve seat 3 in the time range Δt2.

[0032] 8, the sudden waveform in the time range Δt2 is the sliding sound of the valve disc 5 sliding on the valve seat 3. The sliding sound extraction unit 26 extracts the sliding sound of the valve disc 5 sliding on the valve seat 3 by extracting the time range Δt2 set in accordance with the driving of the motor 11 from the detection signal of the acoustic sensor 21. Even in such a modified example, the same effect as in the above embodiment can be obtained.

[0033] In the above embodiment, the sliding sound analysis unit 27 of the diagnostic device 23 performs frequency analysis on the sliding sound extracted by the sliding sound extraction unit 26, but this is not limiting. A second modified example will now be described.

[0034] The sliding sound analysis unit 27 of the diagnostic device 23 of the second modified example performs a fractal analysis on the sliding sound extracted by the sliding sound extraction unit 26 to obtain a fractal distribution as shown in Fig. 9. The sliding sound analysis unit 27 stores the initial fractal distribution as shown in Fig. 9 (in other words, before the valve disc 5 and the valve seat 3 deteriorate), and compares the current fractal distribution obtained as described above with the initial fractal distribution to calculate the rate of change in the fractal distribution.

[0035] The abnormality determination unit 28 determines whether the valve disc 5 and the valve seat 3 are abnormal based on whether the rate of change in the fractal distribution calculated by the sliding sound analysis unit 27 is equal to or greater than a predetermined threshold. The deterioration level estimation unit 29 stores, for example, a calculation table (not shown) indicating the relationship between the rate of change in the fractal distribution and the degree of deterioration of the valve disc 5 and the valve seat 3, and uses this calculation table to calculate the degree of deterioration of the valve disc 5 and the valve seat 3 corresponding to the rate of change in the fractal distribution calculated by the sliding sound analysis unit 27. Even in such a modified example, the same effects as those of the above embodiment can be obtained.

[0036] In the above embodiment and the above modified example, the abnormality determination unit 28 of the diagnostic device 23 performs only one of determining whether the rate of change in the frequency distribution is equal to or greater than a predetermined threshold and determining whether the rate of change in the fractal distribution is equal to or greater than a predetermined threshold. However, this is not limiting. The abnormality determination unit 28 of the diagnostic device 23 may perform both the former determination and the latter determination. If the rate of change in the frequency distribution is equal to or greater than a predetermined threshold and the rate of change in the fractal distribution is equal to or greater than a predetermined threshold, the abnormality determination unit 28 determines that the valve 5 and the valve seat 3 are abnormal. If the rate of change in the frequency distribution is equal to or greater than a predetermined threshold and the rate of change in the fractal distribution is less than a predetermined threshold, the abnormality determination unit 28 determines that the valve 5 and the valve seat 3 are a sign of abnormality. If the rate of change in the frequency distribution is less than a predetermined threshold and the rate of change in the fractal distribution is less than a predetermined threshold, the abnormality determination unit 28 determines that the valve 5 and the valve seat 3 are normal. If the rate of change in the frequency distribution is less than a predetermined threshold and the rate of change in the fractal distribution is equal to or greater than a predetermined threshold, the abnormality determination unit 28 determines that a system error has occurred.

[0037] In the above embodiment, the diagnosis target has been described as a gate valve 1, but this is not limited thereto and other valves may be used. For example, as shown in Fig. 10, the diagnosis target may be a globe valve 1A. The globe valve 1A includes a casing 4A having a flow path 2A and a valve seat 3A, a valve element 5A arranged inside the casing 4A and capable of closing the flow path 2A by abutting against the valve seat 3A, a valve stem 6A connected to the valve element 5A and penetrating the casing 4A, a gland packing 7A that slidably supports the valve stem 6A, a valve stem (not shown) arranged outside the casing 4A and having a male thread portion (not shown) that screws into a female thread portion (not shown) of the valve stem 6A, and a handle 12A connected to the valve stem.

[0038] The valve stem is rotated by manually operating the handle 12A. The rotation of the valve stem is converted into the movement of the valve stem 6A, which moves the valve disc 5A up and down in Fig. 10. When the valve disc 5A moves upward in Fig. 10 and separates from the valve seat 3A, it opens the flow path 2A, and when the valve disc 5A moves downward in Fig. 10 and contacts the valve seat 3A, it closes the flow path 2A.

[0039] The acoustic sensor 21 is disposed, for example, on the side of the casing 4A of the globe valve 1A (that is, in the vicinity of the valve seat 3A). Even in such a modified example, the same effects as those of the above embodiment can be obtained. [Explanation of symbols]

[0040] 1. Gate valve 1A globe valve 3,3A valve seat 5,5A Valve body 6,6A valve stem 11 Motor 21 Acoustic Sensor 22 Displacement Sensor 23 Diagnostic equipment

Claims

1. an acoustic sensor that detects sounds generated at the valve disc and valve seat of the valve; a diagnostic device that diagnoses a deterioration state of the valve body and the valve seat using a detection signal from the acoustic sensor, The diagnostic device extracts a sliding sound of the valve disc sliding on the valve seat by extracting a time range set corresponding to the movement of the valve disc from the detection signal of the acoustic sensor, and analyzes the sliding sound to estimate the degree of deterioration of the valve disc and the valve seat.

2. 10. The diagnostic system of claim 1, a displacement sensor that detects the displacement of a valve stem connected to the valve body; The diagnostic device extracts the sliding sound by extracting a time range set corresponding to the displacement of the valve stem detected by the displacement sensor from the detection signal of the acoustic sensor.

3. 10. The diagnostic system of claim 1, a motor that moves the valve body; The diagnostic system is characterized in that the diagnostic device extracts the sliding sound by extracting a time range set corresponding to the driving of the motor from the detection signal of the acoustic sensor.

4. 10. The diagnostic system of claim 1, The diagnostic system is characterized in that the diagnostic device estimates a maintenance timing based on the degree of deterioration of the valve body and the valve seat.

5. 10. The diagnostic system of claim 1, The diagnostic system is characterized in that the diagnostic device analyzes the sliding sound to determine whether the valve body and the valve seat are abnormal.

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