A weak sound wave or tiny gas leakage detection system and method

Abstract

The present invention relates to a weak sound wave or tiny gas leakage detection system and detection method, the detection system includes an acoustic sensor module, a signal operation circuit, an ADC module, and a signal acquisition and real-time processing module. Among them, the acoustic sensor module includes M microphone arrays, each microphone array includes multiple microphones, and the output signal of each microphone is divided into two paths after passing through an isolation capacitor, one path is connected to interface 1 after passing through a first resistor, and serves as the positive output pin of the microphone array; the other path is grounded after passing through a second resistor and connected to interface 2, and serves as the negative output pin of the microphone array; the M microphone arrays output M signals; the signal acquisition and real-time processing module is used to collect and process the digital signals of each microphone array after analog-to-digital conversion, and judge whether each microphone array detects a weak sound wave signal or a tiny gas leakage according to the processing result.

Description

Technical Field

[0001] The present invention relates to the field of gas leakage detection, and in particular to a detection method for weak sound waves or weak air sound wave signals caused by tiny gas leakage. Background Art

[0002] Gas pressure vessels and pipelines are ubiquitous in the fields of oil and gas storage and transportation and industrial production. Gas leaks can cause serious accidents such as poisoning, fire or explosion. Rapid detection of the presence and location of gas leaks is extremely important for preventing leakage disasters. Countries around the world attach great importance to the development of gas leak detection technology and instruments. Common pressure vessel gas leak detection methods include infrared thermal imaging, helium mass spectrometry, bubble method and acoustic method.

[0003] The thermal imaging method uses the radiation intensity or radiation spectrum of a specific infrared band in the target area of ​​the gas leak to identify gas leaks; this method can only detect large leaks and requires the concentration of the leaking gas to accumulate to a certain value. For small leaks, it is necessary to collect and enrich air samples in the monitoring area. Helium mass spectrometry requires helium to be filled into the container, which is used for leak detection of pipelines and pressure vessels that have suspended production. The bubble method requires that the foaming liquid be applied to the detection area of ​​the pressure vessel and the container pressure must be greater than a certain value, and the size and frequency of the bubbles need to be manually observed. The above methods are inconvenient to install and use on site.

[0004] The acoustic method uses the elastic waves of the container wall and the air sound waves caused by the leak to detect and determine the occurrence of the leak and locate the leak, which corresponds to the acoustic emission method and the sound wave method respectively. The elastic wave method is contact-type, and the acoustic emission sensor needs to be pasted on the container wall to receive the elastic waves caused by the leak. The air sound wave method is non-contact, not affected by the leaked material, and has a larger monitoring range. Small leaks occur before catastrophic large leaks, and effective detection of them can prevent them from happening and avoid disasters. The sound wave signals caused by small leaks are very weak, and the sensitivity of traditional acoustic leak detection methods is difficult to meet actual needs. Most of them can only detect leaks with large apertures and large pressure differences, resulting in only large leaks and poor anti-interference capabilities. Summary of the invention

[0005] The purpose of the present invention is to provide a highly sensitive weak sound wave or tiny gas leakage detection system and a detection method. The technical solution is as follows:

[0006] A weak sound wave or tiny gas leakage detection system includes an acoustic sensor module, a signal operation circuit, an ADC module, and a signal acquisition and real-time processing module, wherein:

[0007] The acoustic sensor module includes M microphone arrays, each microphone array includes multiple microphones, and the output signal of each microphone is divided into two paths after passing through the isolation capacitor. One path is connected to the interface 1 after passing through the first resistor, and serves as the positive electrode of the output pin of the microphone array; the other path is grounded after passing through the second resistor and connected to the interface 2, and serves as the negative electrode of the output pin of the microphone array; the M microphone arrays output M signals;

[0008] A signal operation circuit, used for amplifying the output signal of each microphone array through an operational amplifier and then outputting it;

[0009] An ADC module, used for performing analog-to-digital conversion on the output signal of each microphone array after amplification;

[0010] The signal acquisition and real-time processing module is used to collect and process the digital signals of each microphone array after analog-to-digital conversion, and determine whether each microphone array detects a weak sound wave signal or a tiny gas leak based on the processing results.

[0011] Furthermore, an air sound wave control structure module can be configured for each microphone array. The air sound wave control structure module is conical in shape and is stacked by multiple diaphragms. The size of each diaphragm gradually decreases along the axial direction of the cone. The microphone array is fixed on a certain diaphragm of the air sound wave control structure module or on the gap between adjacent diaphragms. An air sound wave control structure module can also be configured for each microphone. The air sound wave control structure module is conical in shape and is stacked by multiple diaphragms. The size of each diaphragm gradually decreases along the axial direction of the cone. The microphone is fixed on a certain diaphragm of the air sound wave control structure module or on the gap between adjacent diaphragms.

[0012] Furthermore, a display module is included for visually outputting the detection results of each microphone array for weak sound wave signals or tiny gas leaks.

[0013] Furthermore, the output signal of each microphone array is connected to a signal operation circuit. Assuming that the number of microphones in a certain microphone array is N, it can be specifically: interface 1 is connected to the positive input interface of the operational amplifier, a third resistor is connected between the negative input of the operational amplifier and the output interface 7 of the operational amplifier, a fourth resistor is connected between the negative input of the operational amplifier and the negative pole of the power supply, and the ratio of the third resistor to the fourth resistor is not less than the number of microphones N. Specifically, interface 1 of the microphone array can also be connected to the negative input interface 5 of the operational amplifier, a fifth resistor is connected between the negative input interface 5 of the operational amplifier and the output interface 8, the positive input interface 6 of the operational amplifier is connected to the negative pole of the power supply, and the resistance value of the fifth resistor is not less than the resistance value of the first resistor.

[0014] Furthermore, the signal acquisition and real-time processing module includes a microcontroller and a microprocessor. Under the control of the microcontroller, the digital signals output by each microphone array are collected and stored through the ADC module. The continuous digital signal output by each microphone array is converted into an amplitude-frequency signal through Fourier transform. The microprocessor determines whether each microphone array detects a weak sound wave signal or a tiny gas leak based on the amplitude-frequency signal.

[0015] The method for detecting weak sound waves or tiny gas leaks implemented by the system described in claims 1-6 is characterized in that the continuous digital signal output by each microphone array is converted into an amplitude-frequency signal through Fourier transform, and an amplitude threshold and frequency band are preset. The signal acquisition and real-time processing module compares the amplitude of each frequency point of the amplitude-frequency data with the amplitude threshold, and counts the frequency points whose amplitudes are greater than the amplitude threshold. When the amplitudes of a certain proportion of frequency points within the frequency band of a certain microphone array are greater than the amplitude threshold, it is determined that the microphone array has detected a weak sound wave signal or a tiny gas leak.

[0016] The method for detecting weak sound waves or tiny gas leaks according to claim 8 is characterized in that, for M microphone arrays, a one-dimensional array with M elements is obtained, called a leakage detection result array, each array element stores 0 or 1, 0 indicates no leakage, and 1 indicates leakage; this array is transmitted to a display module for visual display. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic structural diagram of a weak sound wave or tiny gas leakage detection system of the present invention.

[0018] Figure 2 A circuit diagram of the acoustic sensor module 101 according to Embodiment 1 of the present invention.

[0019] Figure 3 The signal operation circuit 102 of the embodiment 1 of the present invention. (a) and (b) are schematic diagrams of two signal operation circuits, which are two implementation forms.

[0020] Figure 4 Small leak detection sensitivity test method.

[0021] Figure 5 Results of sensitivity tests for small leak detection.

[0022] Figure 6 Test method for visual detection of tiny leaks.

[0023] Figure 7 Test results for visual detection of tiny leaks.

[0024] Figure 8The air sound wave control structure module 200 of Example 2.

[0025] Fig. 9 The amplification effect of the air sound wave control structure of Example 2. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention are described in further detail below.

[0027] Example 1

[0028] like Figure 1 As shown, Embodiment 1 of the present invention is composed of an acoustic sensor module 101, a signal operation circuit 102, an analog-to-digital conversion module (ADC module) 104, a signal acquisition and real-time processing module 106, a host computer display module 107, etc. (excluding the air sound wave control structure module 200 shown in the figure). In this embodiment, the main body of the acoustic sensor module 101 is a weak sound wave detection array composed of M microphone arrays 301 in parallel.

[0029] Acoustic Sensor Module 101:

[0030] like Figure 2 As shown, each microphone array 301 is mainly composed of N MEMS microphone chips connected on a circuit board. The microphone is an analog voltage output type microphone. The output signal of each microphone is connected to a pin of an isolation capacitor, and the other pin of the isolation capacitor is connected to a pin of a second resistor. The other pin of the second resistor is connected to the negative pole of the microphone power supply, as interface 2. The connection point between the isolation capacitor and the second resistor is connected to a pin of the first resistor. The other pin of the first resistor is connected to interface 1. N microphones 1, microphone 2, microphone 3, ..., the other pins of the corresponding first resistors are N in total, connected together, connected to interface 1, and used as the positive output pin of the microphone array 301. N microphones 1, microphone 2, microphone 3, ..., the other pins of the corresponding second resistors are N in total, connected together and connected to the negative pole of the microphone power supply, and at the same time connected to interface 1, as the negative output pin of the microphone array 301. The number of MEMS microphone chips N = 16.

[0031] Signal operation circuit 102:

[0032] like Figure 3 As shown, each microphone array 301 is connected to a signal operation circuit 102, and M microphone arrays 301 are connected to M signal processing circuits to generate M outputs in total.

[0033] The output interface 1 of the microphone array 301 is connected to the positive input interface 3 of the operational amplifier, a third resistor is connected between the negative input terminal of the operational amplifier and the output interface 7 of the operational amplifier, and a fourth resistor is connected between the negative input terminal of the operational amplifier and the negative power supply. The ratio of the third resistor to the fourth resistor is not less than N. N is the number of microphones on the microphone array 301.

[0034] The output interface 1 of the microphone array 301 can also be connected to the negative input interface 5 of the operational amplifier, and a fifth resistor is connected between the negative input interface 5 of the operational amplifier and the output interface 8. The positive input interface 6 of the operational amplifier is connected to the negative electrode of the power supply. The resistance value of the fifth resistor is not less than the resistance value of the first resistor.

[0035] ADC module 104:

[0036] like Figure 1 As shown, the ADC conversion module 104 performs analog-to-digital conversion on the output signals of the M microphone arrays output by the signal operation circuit 102, i.e., the M channels, and the microcontroller 123FPGA collects the data into the microcontroller 123 for analysis and processing. The ADC module 104 is mainly composed of Q P-channel ADC chips 105, where P*Q is greater than M. The ADC chip 105 is a multi-channel synchronous analog-to-digital conversion chip, and multi-chip synchronous acquisition can be achieved through the chip selection function. The ADC chip 105 is connected to the microcontroller 123 through a data transmission line 121 and a chip selection control line 122. The multiple ADC chips 105 can be divided into several groups, and the same data transmission line 121 used by each group transmits data to the microcontroller 123; the chip selection control line 122 is used to distinguish the outputs of different ADC chips.

[0037] Signal acquisition and real-time processing module 106:

[0038] like Figure 1 As shown, the signal acquisition and real-time processing module 106 is mainly composed of a microcontroller 123FPGA and a microprocessor 124ARM. The microcontroller 123 reads the voltage signal of the multi-channel acoustic sensor module 101 and stores it alternately in two DDR areas. When the first area is full of a certain number of points of all channels, the data continues to be stored in the second area, and the data in the first area is transferred to the microprocessor 124 through DMA for Fourier transform processing to obtain amplitude-frequency data. When the Fourier transform of all channel data in the first area is completed, wait for the second area to store data to be full, then start storing data in the first area, and process the data in the second area, and so on. The cycle realizes the real-time acquisition and processing of the voltage signals of the acoustic sensor modules of all channels.

[0039] Since the frequency response of the acoustic sensor module 101 and the gas leakage sound are broadband signals, when the microphone array 301 detects a leak, the amplitude at each frequency point will increase. Set an amplitude threshold, compare it with the amplitude of each frequency point of the amplitude-frequency data, count the frequency points whose amplitude is greater than the amplitude threshold, and when the amplitude of a certain proportion of frequency points in the frequency band is greater than the amplitude threshold, it is judged that the channel has detected a leakage signal, and a gas leak has occurred near the microphone of the channel. This ratio can be set to 70%. A one-dimensional array with the same number of elements as the number M of microphone arrays 301 will be obtained, which is called the leakage detection result array. Each array element stores 0 or 1, 0 means no leakage, and 1 means leakage. This array is transmitted to the host computer for display, so as to realize the real-time detection and display of micro-leaks using the acoustic sensor modules 101 of all channels.

[0040] Host computer display module 107:

[0041] The upper computer display module 107 receives the data of the leakage detection result array through the serial port, and uses M Boolean lights to form the upper computer indicator light 108 to display the leakage detection result. The i-th light is on, indicating that the i-th microphone array 301 has detected a leakage signal.

[0042] The following is a test of the detection performance of Example 1.

[0043] (1) Test of weak sound wave amplification effect

[0044] The acoustic wave amplification and detection performance of the acoustic sensor module 101 was tested. The test scheme is: use a speaker to play sound signals of different frequencies, for each frequency, move the position of the acoustic sensor module 101, and record the output amplitude of the acoustic sensor module 101 after connecting to the signal operation circuit 102.

[0045] The test results are shown in Table 1. The first column in the figure is the offset angle of the leakage source relative to the microphone array 301, and the second to fourth columns are the gains of the microphone array 301 at different frequencies, that is, the ratio of the output amplitude after the acoustic sensor module 101 is connected to the signal operation circuit to the output amplitude of a single microphone. It can be seen that the amplification factor is more than 10 times.

[0046] Table 1 Amplification effect of the acoustic sensor module 101.

[0047]

[0048] (2) Leak detection sensitivity test method:

[0049] First, the acoustic sensor module 101 is used to measure the ambient noise signal, perform Fourier transform, and take the average value to obtain the average amplitude Vn of the ambient noise.

[0050] Then, the air pump 801 is used to inflate and pressurize the gas tank 804 through the air inlet valve 802. A pressure gauge 803 and a leakage hole device 805 are installed on the gas tank 804. A total of four leakage hole devices of Φ0.1mm, Φ0.2mm, Φ0.3mm, and Φ0.5mm are processed. When the pressure of the pressure gauge 803 rises to a certain value, the air inlet valve 802 is closed to allow the gas to leak naturally, so that the pressure of the gas tank 804 gradually decreases to 0. At the same time, the value of the pressure gauge 803 is read and the signal after the acoustic sensor module 101 is connected to the signal operation circuit 102 is recorded. The collected signal is Fourier transformed and the average is taken to obtain the average amplitude VA of the leakage sound of the measured pipeline.

[0051] Assume that the volume of gas tank 804 is V0, the ambient temperature is T0, and the atmospheric pressure is p0. When leakage is occurring, assume that the air pressure recorded at time t1 and t2 is p1 and p2. The average leakage rate during this period is:

[0052]

[0053] Test results:

[0054] The change process of the average amplitude VA of the leakage sound and the leakage rate Q measured by the acoustic sensor module 101 under different test conditions. As the leakage rate Q decreases, the intensity of the leakage sound also decreases. When the leakage rate decreases to a certain value, the amplitude VA of the leakage sound no longer changes and is lower than the average amplitude Vn of the ambient noise, indicating that no leakage can be detected. The corresponding leakage rate at this time is the lower limit of leakage detection. The different lower limits of leakage rate detection are summarized into Figure 5 It can be found that when the leakage rate is 4.4234mL / s, 0.04171mL / s, 0.02195mL / s, and 0.0878mL / s, the leakage can be detected after three tests respectively. Therefore, this method can detect gas leakage below 0.1mL / s, and the sensitivity is very high.

[0055] (3) Test method that can realize visual detection of tiny gas leaks of 0.1 mL / s:

[0056] like Figure 6 As shown, fill the gas cylinder 804 with 50kPa gas, connect the outlet valve 701 on the gas cylinder 804 to the standard leakage rate generator 701 with a hose, and connect the standard leakage rate generator 701 to the leakage head 703 with a hose. The standard leakage rate generator 701 can generate a stable gas leakage of 0.1mL / s at a pressure difference of 50kPa, and apply ultrasonic amplification liquid on the leakage hole of the leakage head 703 to assist in the test. Use multiple acoustic sensor modules 101 to form an array and place it near the leakage head 703. According to Figure 1 The connection method shown is used to detect and display the leakage detection result on the host computer. If the light is on, it means that the acoustic sensor module 101 corresponding to the light has detected a gas leakage of 0.1 mL / s.

[0057] Test results:

[0058] like Figure 7 As shown, when the air outlet valve is opened, a gas leakage of 0.1 mL / s occurs, and the indicator light in the center area of ​​the upper computer indicator light 108 is on, indicating that a gas leakage of 0.1 mL / s is detected, and the leakage point is in the center area of ​​the array composed of the acoustic sensor modules 101; when the air outlet valve 701 is opened and the position of the leakage head 703 is moved, the indicator light in the area to the left of the center of the upper computer indicator light 108 is on, indicating that a gas leakage of 0.1 mL / s is detected, and the position of the leakage point deviates from the center; when the air outlet valve 701 is closed, no leakage occurs, and the upper computer indicator light 108 is completely off, indicating that no gas leakage is detected.

[0059] Example 2

[0060] like Figure 2 As shown, the present invention is composed of an acoustic sensor module 101, a signal operation circuit 102, an analog-to-digital conversion module (ADC module) 104, a signal acquisition and real-time processing module 106, a host computer display module 107, an air sound wave control structure module 200, etc. Embodiment 2 improves on Embodiment 1 by adding an air sound wave control structure module 200 to each microphone in each microphone array 301. The acoustic sensor module 101 of Embodiment 2 becomes a weak sound wave detection array composed of a plurality of air sound wave control structure modules 200 in parallel, and a microphone is embedded in each air sound wave control structure module 200.

[0061] Air sound wave control structure module 200:

[0062] like Figure 8As shown, the air sound wave control structure module 200 has a conical shape and is composed of many stacked diaphragms. The diaphragm can be in a variety of shapes. In this embodiment, it is circular and is called a disc. The diameter of the disc gradually decreases along the axial direction of the cone. These discs are numbered 202, 203 from large to small. . . . In order to ensure sufficient structural strength, the thickness of the disc and the distance between adjacent discs can remain unchanged. All discs are fixedly connected by more than two fixing ribs 201. An operating rod 206 is fixedly connected to the first disc 202 for fixing the air sound wave control structure module 200. A microphone array mounting hole 204 is provided between two adjacent discs. The entire structure can be made by 3D printing. When the sound propagates along the axis of the cone to the gap formed by each disc, sound waves of different frequencies will reside in different gaps and be amplified. When the sound frequency caused by the leakage of the pressure vessel is relatively high, the microphone mounting hole should be set on a disc with a relatively small diameter. When the sound frequency caused by the leakage of the pressure vessel is relatively low, the microphone mounting hole should be set on a disc with a larger diameter.

[0063] The sound wave amplification and detection performance of the sound wave control structure module 200 was tested. The test method is: a wide-band speaker plays sounds of different frequencies, a microphone is installed in the microphone array installation hole 204 of the sound wave control structure module 200, and sound wave signals of different frequencies are received and converted into voltage signals; then the sound wave control structure module 200 is removed, and only the microphone is retained to receive sound wave signals of different frequencies, and finally the amplitudes of the two are divided, which is the amplification factor.

[0064] Test results such as Fig. 9 As shown, it can be seen that the amplification factor is 2-8 times in a wide frequency band. Then a sound signal of a certain frequency is played, the microphone is installed in the sound wave control structure, the structure is rotated, and its directivity is tested. The result is shown in the figure. It can be seen that after the microphone is installed in the sound wave control structure module 200, it has good directivity without losing sensitivity, and can be used to distinguish leakage sound sources in different directions.

[0065] Example 2

[0066] like Figure 2As shown, the present invention is composed of an acoustic sensor module 101, a signal operation circuit 102, an analog-to-digital conversion module (ADC module) 104, a signal acquisition and real-time processing module 106, a host computer display module 107, an air sound wave control structure module 200, etc. Example 2 improves Example 1 by adding an air sound wave control structure module 200 to each microphone in each microphone array 301. The specific structure of the acoustic sensor module 101 of Example 2 is changed as follows: Each microphone array includes N parallel air sound wave control structure modules 200, and each air sound wave control structure module 200 is embedded with a microphone. The different embedded positions of the microphones can improve the sensitivity of detecting weak sound wave signals of different frequencies. Then, the entire weak sound wave detection array is formed by M microphone arrays in parallel.

[0067] Air sound wave control structure module 200:

[0068] like Figure 8 As shown, the air sound wave control structure module 200 has a conical shape and is composed of many stacked diaphragms. The diaphragm can be in a variety of shapes. In this embodiment, it is circular and is called a disc. The diameter of the disc gradually decreases along the axial direction of the cone. These discs are numbered 202, 203 from large to small. . . . In order to ensure sufficient structural strength, the thickness of the disc and the distance between adjacent discs can remain unchanged. All discs are fixedly connected by more than two fixing ribs 201. An operating rod 206 is fixedly connected to the first disc 202 for fixing the air sound wave control structure module 200. A microphone array mounting hole 204 is provided between two adjacent discs. The entire structure can be made by 3D printing. When the sound propagates along the axis of the cone to the gap formed by each disc, sound waves of different frequencies will reside in different gaps and be amplified. When the sound frequency caused by the leakage of the pressure vessel is relatively high, the microphone mounting hole should be set on a disc with a relatively small diameter. When the sound frequency caused by the leakage of the pressure vessel is relatively low, the microphone mounting hole should be set on a disc with a larger diameter.

[0069] The sound wave amplification and detection performance of the sound wave control structure module 200 was tested. The test method is: a wide-band speaker plays sounds of different frequencies, a microphone is installed in the microphone array installation hole 204 of the sound wave control structure module 200, and sound wave signals of different frequencies are received and converted into voltage signals; then the sound wave control structure module 200 is removed, and only the microphone is retained to receive sound wave signals of different frequencies, and finally the amplitudes of the two are divided, which is the amplification factor.

[0070] Test results such as Fig. 9As shown, it can be seen that the amplification factor is 2-8 times in a wide frequency band. Then a sound signal of a certain frequency is played, the microphone is installed in the sound wave control structure, the structure is rotated, and its directivity is tested. The result is shown in the figure. It can be seen that after the microphone is installed in the sound wave control structure module 200, it has good directivity without losing sensitivity, and can be used to distinguish leakage sound sources in different directions.

[0071] Example 3

[0072] This embodiment also adds multiple air sound wave control structure modules 200. Different from Embodiment 2, the number of air sound wave control structure modules 200 in this embodiment is M, and one air sound wave control structure module 200 is configured for each microphone array 301. The acoustic sensor module 101 of Embodiment 2 becomes a weak sound wave detection array composed of multiple air sound wave control structure modules 200 arranged in parallel, and a microphone array 301 is embedded in each air sound wave control structure module 200.

[0073] Unless otherwise specified, the models of the components in the embodiments of the present invention are not limited, and any device that can perform the above functions may be used.

[0074] Those skilled in the art will appreciate that the accompanying drawing is only a schematic diagram of a preferred embodiment, and the serial numbers of the embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A weak sound wave or tiny gas leakage detection system, including an acoustic sensor module, a signal operation circuit, an ADC module, a signal acquisition and real-time processing module and an air sound wave control structure module, wherein: The acoustic sensor module includes M microphone arrays, each microphone array includes multiple microphones, and the output signal of each microphone is divided into two paths after passing through the isolation capacitor. One path is connected to the interface 1 after passing through the first resistor, and serves as the positive electrode of the output pin of the microphone array; the other path is grounded after passing through the second resistor and connected to the interface 2, and serves as the negative electrode of the output pin of the microphone array; the M microphone arrays output M signals; A signal operation circuit, used for amplifying the output signal of each microphone array through an operational amplifier and then outputting it; An ADC module, used for performing analog-to-digital conversion on the output signal of each microphone array after amplification; The signal acquisition and real-time processing module is used to collect and process the digital signals of each microphone array after analog-to-digital conversion, and determine whether each microphone array detects a weak sound wave signal or a small gas leak based on the processing results; An air sound wave control structure module is configured for each microphone array. The air sound wave control structure module is conical in shape and is composed of multiple stacked diaphragms. The size of each diaphragm gradually decreases along the axial direction of the cone, and a microphone array mounting hole is arranged between two adjacent diaphragms for fixing the microphone array module. When the sound propagates along the axis of the conical air sound wave control structure module to the gap formed by each diaphragm, sound waves of different frequencies reside in different gaps and are amplified and picked up by the microphone array. When the sound frequency caused by the leakage of the pressure vessel is relatively high, the microphone array mounting hole should be set on an adjacent diaphragm with a smaller diameter; when the sound frequency caused by the leakage of the pressure vessel is relatively low, the microphone array mounting hole should be set on an adjacent diaphragm with a larger diameter.

2. The weak sound wave or tiny gas leakage detection system according to claim 1, characterized in that: The output signal of each microphone array is connected to a signal operation circuit. Assuming that the number of microphones in a certain microphone array is N, specifically: interface 1 is connected to the positive input interface of the operational amplifier, a third resistor is connected between the negative input terminal of the operational amplifier and the output interface 7 of the operational amplifier, a fourth resistor is connected between the negative input terminal of the operational amplifier and the negative pole of the power supply, and the ratio of the third resistor to the fourth resistor is not less than the number of microphones N.

3. The weak sound wave or tiny gas leakage detection system according to claim 1, characterized in that: The signal acquisition and real-time processing module includes a microcontroller and a microprocessor. Under the control of the microcontroller, the digital signals output by each microphone array are collected and stored through the ADC module. The continuous digital signal output by each microphone array is converted into an amplitude-frequency signal through Fourier transform. The microprocessor determines whether each microphone array detects a weak sound wave signal or a tiny gas leak based on the amplitude-frequency signal.

4. The weak sound wave or tiny gas leakage detection system according to claim 1, characterized in that: It also includes a display module for visually outputting the detection results of each microphone array for weak sound wave signals or tiny gas leaks. For M microphone arrays, a one-dimensional array with M elements is obtained, called the leakage detection result array, and each array element stores 0 or 1, 0 indicates no leakage, and 1 indicates leakage; this array is transmitted to the display module for visual display.

5. The method for detecting weak sound waves or tiny gas leaks implemented by the system according to any one of claims 1 to 4, characterized in that: The continuous digital signal output by each microphone array is converted into an amplitude-frequency signal through Fourier transform. The amplitude threshold and frequency band are preset. The signal acquisition and real-time processing module compares the amplitude of each frequency point of the amplitude-frequency data with the amplitude threshold, and counts the frequency points with amplitudes greater than the amplitude threshold. When the amplitudes of a certain proportion of frequency points within the frequency band of a certain microphone array are greater than the amplitude threshold, it is determined that this microphone array has detected a weak sound wave signal or a tiny gas leak.

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