A leak detection device and a leak detection method

Abstract

The application discloses a kind of leakage detection device and leakage detection method, through signal amplification circuit in leakage detection device, realize the three-stage amplification to electric signal, so as to weak electric signal can be effectively amplified, so that processor can be based on amplified signal, judge whether the leakage of to-be-detected container occurs, realize the detection of micro leakage, improve detection sensitivity;And, when to-be-detected container forms acoustic emission source and produces elastic vibration, sensor can detect the vibration frequency of the elastic vibration, then based on the amplification processing of signal amplification circuit, so that processor can detect whether to-be-detected container has leaked, so that the leakage of to-be-detected container can be detected based on acoustic emission technology, nondestructive testing is realized, and secondary damage to to-be-detected container is avoided.

Description

Technical Field

[0001] This invention relates to the field of detection technology, and more particularly to a leak detection device and a leak detection method. Background Technology

[0002] One current method for detecting leaks in pressure vessels is the bubble detection method. This method involves filling the vessel under test with a certain pressure of leak-indicating gas and then placing it in a liquid. The gas enters the surrounding liquid through the leak hole, forming bubbles. The location where the bubbles form is the location of the leak. Based on the bubble formation rate, bubble size, and the physical properties of the gas and liquid used, the leakage rate of the leak can be calculated.

[0003] However, the bubble detection method is a non-destructive testing method, which requires disassembling the container to be tested, which can easily cause secondary damage. In addition, this method uses the human eye as an observation tool to record the number of leaking bubbles, which is time-consuming and labor-intensive and prone to errors. Moreover, the bubble method is even more time-consuming for micro-leakage.

[0004] Therefore, how to implement non-destructive testing methods to avoid secondary damage to the container under test, while also enabling the detection of micro-leakage, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] This invention provides a leak detection device and a leak detection method to achieve non-destructive testing, thereby avoiding secondary damage to the container under test. It can also detect micro-leaks and improve detection sensitivity.

[0006] In a first aspect, embodiments of the present invention provide a leakage detection device, comprising: a sensor, a signal amplification circuit, and a processor;

[0007] The sensor is used to: collect the vibration frequency of the container being tested when it vibrates and convert it into a corresponding electrical signal;

[0008] The signal amplification circuit is used to: amplify the converted electrical signal to obtain an amplified signal;

[0009] The processor is used to: detect whether the container to be tested has leaked based on the amplified signal;

[0010] The signal amplification circuit includes: a first amplification sub-circuit, a second amplification sub-circuit, a filter sub-circuit, and a third amplification sub-circuit;

[0011] The first amplification sub-circuit is used to: perform signal-to-noise ratio enhancement processing and differential processing on the electrical signal to obtain a biphase signal;

[0012] The second amplifier sub-circuit is used to: perform operational amplification and single-to-two-phase conversion processing on the two-phase signal to obtain a single-phase signal;

[0013] The filter sub-circuit is used to: filter the single-phase signal;

[0014] The third amplifier sub-circuit is used to: perform gain processing and load enhancement processing on the filtered single-phase signal and then output the amplified signal.

[0015] Secondly, embodiments of the present invention provide a leakage detection method, including:

[0016] The vibration frequency of the container under test is obtained when it vibrates, and the vibration frequency is converted into a corresponding electrical signal;

[0017] The electrical signal is amplified to obtain an amplified signal;

[0018] Based on a preset sampling frequency, the amplified signal is converted to obtain a frequency domain distribution map;

[0019] The integral area of ​​the curve within the reference frequency range in the frequency domain distribution diagram is determined to obtain the reference area;

[0020] Based on the probability of the relationship between the reference area and the preset area occurring within a preset number of judgments, it is determined whether the container to be detected has leaked;

[0021] The amplified signal is obtained in the following way:

[0022] The electrical signal is subjected to signal-to-noise ratio enhancement and differential processing to obtain a biphase signal;

[0023] The two-phase signal is subjected to operational amplification and single-phase to two-phase conversion to obtain a single-phase signal;

[0024] The single-phase signal is filtered.

[0025] The amplified signal is output after the filtered single-phase signal undergoes gain processing and load boosting processing.

[0026] The beneficial effects of this invention are as follows:

[0027] This invention provides a leakage detection device and method. The leakage detection device utilizes a signal amplification circuit to achieve three-stage amplification of electrical signals, effectively amplifying weak electrical signals. This allows the processor to determine whether a leak has occurred in the container under test based on the amplified signal, enabling the detection of micro-leakage and improving detection sensitivity. Furthermore, when the container under test generates elastic vibrations as an acoustic emission source, the sensor can detect the vibration frequency of these elastic vibrations. After amplification by the signal amplification circuit, the processor can detect whether a leak has occurred in the container under test. This allows for the detection of leaks in the container under test based on acoustic emission technology, achieving non-destructive testing and avoiding secondary damage to the container. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a signal amplification circuit provided in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the first amplification sub-circuit provided in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of the second amplification sub-circuit provided in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the filter sub-circuit provided in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the third amplifier sub-circuit provided in an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the power management sub-circuit provided in an embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of the structure of a leak detection device provided in an embodiment of the present invention;

[0035] Figure 8 This is a top view of the shielding box provided in an embodiment of the present invention;

[0036] Figure 9 This is a control block diagram of the signal acquisition program provided in an embodiment of the present invention;

[0037] Figure 10 A flowchart of a specific embodiment provided in this invention;

[0038] Figure 11 This is a flowchart of a leakage detection method provided in an embodiment of the present invention. Detailed Implementation

[0039] The specific embodiments of a leak detection device and leak detection method provided by the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0040] Current methods for detecting leaks in pressure vessels include non-destructive testing (NDT) and non-destructive testing (NDT). Among these, non-destructive testing methods include bubble detection. This method involves filling the vessel under test with a certain pressure of leak-indicating gas and then immersing it in liquid. The gas enters the surrounding liquid through the leak hole, forming bubbles. The location of the bubble formation indicates the location of the leak. Based on the bubble formation rate, bubble size, and the physical properties of the gas and liquid used, the leakage rate of the leak can be calculated.

[0041] Non-destructive testing methods include: infrared thermal imaging, ultrasonic testing, and acoustic emission testing.

[0042] Infrared thermal imaging: The principle is that when a container under test leaks, the temperature at the leak point will drop, thus lowering the surface temperature of the equipment with the leak and creating a temperature field disturbance. Infrared thermal imaging technology can be used to obtain the temperature field on the surface of the container under test, allowing for leak detection and location by observing the temperature field disturbance caused by the leak.

[0043] Ultrasonic detection method: When the container to be tested contains gas and a leak occurs, the gas will rush out from the leak hole due to the large pressure difference between the inside and outside. When the leak hole is small and the Reynolds number is high, the rushing gas forms turbulence. The turbulence generates sound waves of a certain frequency near the leak hole. The frequency of the sound wave vibration is related to the size of the leak hole. When the leak hole is large, the sound of leaking gas can be heard by the human ear. When the leak hole is very small and the sound wave frequency is greater than 20kHz, the human ear cannot hear it. In this case, leak detection can be performed by capturing high-frequency short-wave signals. At the same time, the directional characteristic of ultrasonic intensity rapidly decreasing with increasing propagation distance can be used to locate the leak.

[0044] Acoustic emission detection method: When the surface of the container to be tested is subjected to stress, an acoustic emission source is formed. The acoustic emission source propagates the acoustic emission signal through the material itself, thereby causing elastic vibration on the material surface. The weak elastic vibration is detected by the acoustic emission sensor and the weak vibration energy is converted into an electrical signal. The electrical signal is amplified by the amplifier and collected by the system. The system analyzes and processes the data, displays and records the characteristic signals, and then uses the characteristic signals to determine whether there are defects in the container to be tested and infers whether the container to be tested has leaked or broken.

[0045] Based on this, in one or more embodiments, acoustic emission detection technology can be used to detect micro-leakage while achieving a non-destructive testing method to avoid secondary damage to the container under test, thereby improving detection sensitivity.

[0046] See Figure 1 The schematic diagram of the signal amplification circuit shown includes: a first amplification sub-circuit 10, a second amplification sub-circuit 20, a filter sub-circuit 30, and a third amplification sub-circuit 40.

[0047] The first amplifier sub-circuit 10 is used to: perform signal-to-noise ratio enhancement and differential processing on the electrical signal to obtain a biphase signal;

[0048] The second amplifier sub-circuit 20 is used to: perform operational amplification and single-to-two-phase conversion on the two-phase signal to obtain a single-phase signal;

[0049] The filter sub-circuit 30 is used to filter single-phase signals;

[0050] The third amplifier sub-circuit 40 is used to: perform gain processing and load enhancement processing on the filtered single-phase signal before outputting it.

[0051] The biphase signal output by the first amplification sub-circuit may include two sub-signals, which are equal in magnitude and opposite in phase.

[0052] In this way, three-stage amplification of the electrical signal can be achieved, which can effectively amplify the weak electrical signal so that the processor can determine whether leakage has occurred in the object to be detected based on the amplified signal, realize the detection of micro-leakage, and improve the detection sensitivity.

[0053] The following sections will provide a detailed introduction to each structure in the signal amplifier circuit.

[0054] 1. First amplifier sub-circuit.

[0055] In one or more embodiments, see Figure 2 The schematic diagram of the first amplification sub-circuit 10 shown includes: a differential processing module 11, a signal-to-noise ratio improvement module 12, a bias voltage generation module w1, and a first filtering module 14.

[0056] There are two signal-to-noise ratio enhancement modules 12 and bias voltage generation modules w1. The first input terminal (e.g., D+) of the first amplification sub-circuit 10 and the differential processing module 11 are respectively provided between the first input terminal (e.g., D-) of the first amplification sub-circuit 10 and the differential processing module 11. The first filtering module 14 is electrically connected to the differential processing module 11 and the power supply terminal VIN respectively.

[0057] The signal-to-noise ratio enhancement module 12 is used to: perform noise reduction, impedance matching and clamping processing on the electrical signal and then input it to the bias voltage generation module w1;

[0058] The bias voltage generation module w1 is used to generate a corresponding first bias voltage signal based on the signal processed by the signal-to-noise ratio improvement module 12.

[0059] The first filtering module 14 is used to filter the power signal provided by the power supply terminal VIN and then output it to the differential processing module 11;

[0060] The differential processing module 11 is used to: map the first bias voltage signal and the signal output by the first filter module 14, and perform differential processing on the mapped signal to obtain a two-phase signal.

[0061] Thus, the differential processing module, signal-to-noise ratio enhancement module, bias voltage generation module, and first filtering module can be used to improve the signal-to-noise ratio and perform differential processing on the electrical signal, enabling the first amplification sub-circuit to output a bi-phase signal. This, in turn, gives the first amplification sub-circuit a high common-mode rejection ratio, improves the signal-to-noise ratio of the electrical signal, and enhances its anti-interference capability.

[0062] In one or more embodiments, such as Figure 2 As shown, the differential processing module 11 includes: a first transistor T1 and a second transistor T2 arranged symmetrically, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a constant current diode D1;

[0063] The differential processing module 11 has a first input terminal, a second input terminal, a first output terminal (i.e., C1 terminal), and a second output terminal (i.e., C2 terminal);

[0064] The base of the first transistor T1 and the base of the second transistor T2 are respectively electrically connected to the two bias voltage generation modules w1 in a one-to-one correspondence. The emitter of the first transistor T1 is electrically connected to the first end of the first resistor R1. The collector of the first transistor T1 is electrically connected to the first end and the first output end of the second resistor R2 respectively.

[0065] The emitter of the second transistor T2 is electrically connected to the first end of the third resistor R3, and the collector of the second transistor T2 is electrically connected to the first end and the second output end of the fourth resistor R4, respectively.

[0066] The second terminal of the first resistor R1 and the second terminal of the third resistor R3 are both electrically connected to the positive terminal of the constant current diode D1.

[0067] The second end of the second resistor R2 and the second end of the fourth resistor R4 are both electrically connected to the power supply terminal VIN and the first filter module 14.

[0068] The negative terminal of the constant current diode D1 is electrically connected to the ground terminal GND.

[0069] Among them, the first transistor T1 and the second transistor T2 can be, but are not limited to, a pair of NPN transistors, in order to reduce the input resistance of the two transistors and improve the sensitivity to electrical signals. Based on the processing of low noise signals, they can be widely used in low noise signal amplification circuits.

[0070] exist Figure 2 In this configuration, the first resistor R1 to the fourth resistor R4 can collectively control the amplification factor. For example, a 5x gain amplification can be achieved through the first transistor T1, the first resistor R1, and the second resistor R2. Therefore, through symmetrical arrangement, the differential processing module 11 can achieve a 10x gain amplification. Of course, in one or more embodiments, the gain amplification factor of the differential processing module 11 is not limited to 10x; this is merely an example.

[0071] Furthermore, continue to combine Figure 2 As shown, the first resistor R1 and the third resistor R3 are both electrically connected to the positive terminal of the constant current diode D1. The constant current diode D1 is affected by the bias voltage of the base of the two transistors and can be in a constant current working state. While amplifying the electrical signal, it can also convert the single-phase electrical signal into a two-phase differential signal (i.e., a two-phase signal), thereby improving the signal-to-noise ratio and improving the anti-interference ability.

[0072] In one or more embodiments, in this differential processing module, the first transistor and the second transistor can feed back the base input signal and map it to the collector output signal, so that the signal output from the collector has the information of the base input signal and has a high signal-to-noise ratio and amplification effect. At the same time, differential processing can be realized to obtain a two-phase signal, thereby realizing the function of the differential processing module.

[0073] In one or more embodiments, the specific structure of the differential processing module 11 is not limited to... Figure 2 As shown, it can also be configured with other structures that can implement the functions of the differential processing module 11, which are not limited here.

[0074] In one or more embodiments, such as Figure 2 As shown, the signal-to-noise ratio enhancement module 12 includes: a magnetic bead FB, a first capacitor C1, a fifth resistor R5, and a clamping diode D2 arranged in series.

[0075] The clamping diode D2 can be, but is not limited to, implemented by two fast-switching diodes connected in series.

[0076] Furthermore, the ferrite bead FB is positioned between the signal input terminal D+ and the first capacitor C1. The ferrite bead FB is used to suppress high-frequency noise and spike interference in the electrical signal and absorb electrostatic pulses, thereby reducing noise. The first capacitor C1 can block DC and pass AC, and the fifth resistor R5 can match the impedance of the electrical signal. The clamping diode D2 can clamp the potential of node N1, so that the voltage range of node N1 can be maintained within the target voltage range (e.g., but not limited to -0.7V to +0.7V). Signals outside this range will be regarded as interference signals, and interference signals can be transmitted to the ground terminal GND through the clamping diode D2, thereby achieving noise reduction, impedance matching, and clamping of the electrical signal.

[0077] In one or more embodiments, the specific structure of the signal-to-noise ratio enhancement module 12 is not limited to... Figure 2 As shown, it can also be configured with other structures that can realize the function of the signal-to-noise ratio improvement module 12, which are not limited here.

[0078] In one or more embodiments, such as Figure 2 As shown, the first filtering module 14 includes a second capacitor C2 and a third capacitor C3 connected in parallel between the ground terminal GND and the differential processing module 11.

[0079] The first end of the second capacitor C2 and the first end of the third capacitor C3 are respectively electrically connected to the power supply terminal VIN and the differential processing module 11, and the second end of the second capacitor C2 and the second end of the third capacitor C3 are respectively electrically connected to the ground terminal GND.

[0080] Thus, the power signal input at the power supply terminal VIN can be filtered by the second capacitor C2 and the third capacitor C3 to ensure that the power signal input to the differential processing module 11 is a stable voltage signal.

[0081] In one or more embodiments, the specific structure of the first filtering module 14 is not limited to... Figure 2 As shown, it can also be configured with other structures that can realize the function of the first filtering module 14, which are not limited here.

[0082] In one or more embodiments, such as Figure 2 As shown, the bias voltage generation module w1 includes: an eleventh capacitor C11, a fifteenth resistor R15, and a sixteenth resistor R16;

[0083] The bias voltage generation module w1 has an input terminal (i.e., node N1) and an output terminal;

[0084] The first terminal of the eleventh capacitor C11 is electrically connected to the input terminal, and the second terminal of the eleventh capacitor C11 is electrically connected to the first terminal of the fifteenth resistor R15 and the first terminal of the sixteenth resistor R16, respectively.

[0085] The second terminal of the fifteenth resistor R15 is electrically connected to the power supply terminal VIN.

[0086] The second end of the sixteenth resistor R16 is electrically connected to the ground terminal GND.

[0087] Among them, the eleventh capacitor C11 can be used as a coupling capacitor; the fifteenth resistor R15 and the sixteenth resistor R16 can perform voltage division processing on the power supply signal provided by the power supply terminal VIN, thereby providing bias voltage to the base of the first transistor T1 and the second transistor T2, so that the first transistor T1 and the second transistor T2 have a stable static operating point, enabling them to perform amplification and differential processing without distortion.

[0088] In one or more embodiments, the specific structure of the bias voltage generation module w1 is not limited to... Figure 2 As shown, it can also be configured with other structures that can realize the function of bias voltage generation module w1, which are not limited here.

[0089] In summary, in one or more embodiments, such as Figure 2 As shown, the first amplification sub-circuit 10 can first perform noise reduction, impedance matching, and clamping processing on the electrical signal. Then, through the voltage division effect of the fifteenth resistor R15 and the sixteenth resistor R16, it can provide bias voltage to the base of the first transistor T1 and the second transistor T2. After amplification by the first resistor R1 to the fourth resistor R5, the signal of the base of the first transistor T1 and the second transistor T2 can be mapped to the signal output from the collector, and the interference is eliminated. Amplification and differential processing are realized, thereby realizing the signal-to-noise ratio improvement and differential processing of the electrical signal, and outputting a two-phase signal.

[0090] 2. Second amplifier circuit.

[0091] In one or more embodiments, see Figure 3 The schematic diagram of the second amplifier sub-circuit shown includes: a bias voltage generation module w1, an operational amplifier module 21, a second filter module 23, and an output control module w2;

[0092] The bias voltage generation module w1 is located between the output terminal (such as c1 and c2) of the first amplifier sub-circuit and the operational amplifier module 21; the second filter module 23 is located between the power supply terminal VIN and the operational amplifier module 21; the output control module w2 is located between the output terminal of the operational amplifier module 21 and the filter sub-circuit.

[0093] The bias voltage generation module W1 is used to: generate a corresponding second bias voltage signal based on the biphase signal;

[0094] The second filtering module 23 is used to filter the power signal provided by the power supply terminal VIN and then output it to the operational amplifier module 21;

[0095] The operational amplifier module 21 is used to: activate the operational amplifier function according to the second bias voltage signal, and when the operational amplifier function is activated, perform operational amplification processing and single-phase / dual-phase conversion processing on the second bias voltage signal to obtain a single-phase signal;

[0096] The output control module W2 is used to perform impedance matching processing on single-phase signals.

[0097] Thus, the signal-to-noise ratio can be further improved through the second amplifier sub-circuit, and the two-phase signal can be converted into a single-phase signal to achieve further processing and amplification of the electrical signal, thereby realizing the function of the second amplifier sub-circuit.

[0098] In one or more embodiments, such as Figure 3 As shown, the operational amplifier module 21 includes: a first operational amplifier OT1, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a fourth capacitor C4;

[0099] The first input terminal of the first operational amplifier OT1 is electrically connected to the first terminal of the sixth resistor R6, the first terminal of the seventh resistor R7, and the first terminal of the fourth capacitor C4, respectively. The second input terminal of the first operational amplifier OT1 is electrically connected to the first terminal of the eighth resistor R8 and the first terminal of the ninth resistor R9, respectively. The third input terminal of the first operational amplifier OT1 is electrically connected to the second filter module 23. The fourth input terminal of the first operational amplifier OT1 is electrically connected to the ground terminal GND. The output terminal of the first operational amplifier OT1 is electrically connected to the second terminal of the sixth resistor R6 and the second terminal of the fourth capacitor C4, respectively.

[0100] There are two bias voltage generation modules w1. The second end of the seventh resistor R7 and the second end of the eighth resistor R8 are electrically connected to the two bias voltage generation modules w1 respectively; that is, the second end of the seventh resistor R7 is electrically connected to one of the bias voltage generation modules w1, and the second end of the eighth resistor R8 is electrically connected to the other bias voltage generation module w1.

[0101] The second terminal of the ninth resistor R9 is electrically connected to the ground terminal GND.

[0102] Among them, the first operational amplifier OT1 can be, but is not limited to, selected devices with good symmetry; the sixth resistor R6 to the eighth resistor R8 are used as gain control resistors, which can achieve a gain amplification of n times (for example, but not limited to 2 times); the ninth resistor R9 can be used as a balancing resistor at the second input terminal of the first operational amplifier OT1 to reduce the influence of offset current on the output of the first operational amplifier OT1; the fourth capacitor C4 can be used as a compensation capacitor to avoid self-oscillation of the first operational amplifier OT1, thereby ensuring that the first operational amplifier OT1 can work normally and stably.

[0103] Furthermore, both the first and second input terminals of the first operational amplifier OT1 are electrically connected to the bias voltage generation module w1, so that the second bias voltage generated by the bias voltage generation module w1 can be transmitted to the first operational amplifier OT1. The second bias voltage can provide a static operating point to the first operational amplifier OT1, so that the first operational amplifier OT1 operates in the linear region, thereby realizing the amplification and single-to-two-phase conversion of the two-phase signal to obtain a single-phase signal.

[0104] In one or more embodiments, the specific structure of the operational amplifier module 21 is not limited to... Figure 3 As shown, it can also be configured with other structures that can realize the function of the operational amplifier module 21, which are not limited here.

[0105] In one or more embodiments, such as Figure 3 As shown, the second filter module 23 includes: a fifth capacitor C5, a sixth capacitor C6, and a first inductor L1;

[0106] The first terminal of the fifth capacitor C5 and the first terminal of the sixth capacitor C6 are both electrically connected to the ground terminal GND;

[0107] The second terminal of the fifth capacitor C5 and the second terminal of the sixth capacitor C6 are respectively electrically connected to the first terminal of the first inductor L1 and the operational amplifier module 21;

[0108] The second terminal of the first inductor L1 is electrically connected to the power supply terminal VIN.

[0109] When the operational amplifier module 21 includes an active device (such as the first operational amplifier OT1 being an active device), the second filtering module 23 can filter the power signal supplied by the power supply terminal VIN to the first operational amplifier OT1, ensuring that the power signal output by the power supply terminal VIN to the first operational amplifier OT1 is a stable voltage signal, while also ensuring the accuracy and stability of the signal processing by the first operational amplifier OT1.

[0110] In one or more embodiments, the specific structure of the second filtering module 23 is not limited to... Figure 3As shown, it can also be configured with other structures that can realize the function of the second filtering module 23, which are not limited here.

[0111] In one or more embodiments, such as Figure 3 As shown, the bias voltage generation module w1 can also include an eleventh capacitor C11, a fifteenth resistor R15, and a sixteenth resistor R16; that is, the bias voltage generation module w1 in the second amplification sub-circuit 20 and the bias voltage generation module w1 in the first amplification sub-circuit 10 can have the same structure and function, or they can be different. The specific structure can be determined according to actual needs, and no limitation is made here.

[0112] In one or more embodiments, such as Figure 3 As shown, the output control module w2 includes a twelfth capacitor C12 and a seventeenth resistor R17 connected in series.

[0113] Among them, the twelfth capacitor C12 can be used as a coupling capacitor to connect to the next stage, and the seventeenth resistor R17 can be matched with the impedance of the next stage filter sub-circuit, so as to facilitate the filter sub-circuit to process the output single-phase signal.

[0114] In one or more embodiments, the specific structure of the output control module w2 is not limited to... Figure 3 As shown, it can also be configured with other structures that can realize the function of the output control module w2, which are not limited here.

[0115] In summary, in one or more embodiments, the first amplification sub-circuit can perform primary amplification of the electrical signal to improve the signal-to-noise ratio (SNR) of the electrical signal, and the second amplification sub-circuit can further improve the SNR. Thus, after processing by the first and second amplification sub-circuits, the single-phase signal has a high SNR, which facilitates subsequent gain processing to amplify the electrical signal.

[0116] 3. Filter circuit.

[0117] The function of the filter sub-circuit includes filtering out signals other than acoustic emission signals from the electrical signal. Based on the range of the frequency band generated by the acoustic emission of the material during leakage (e.g., 20kHz to 400kHz), a bandpass filter (abbreviated as BPF) can be used. When the bandpass filter includes passive and active filters, passive filters can be used because they are simple to design, inexpensive, small in size, and have low power consumption. This reduces the size and manufacturing cost of the signal amplification circuit, and enables the miniaturization of the signal amplification circuit.

[0118] In one or more embodiments, the filter sub-circuit can be designed based on a fixed-K type normalized low-pass filter (which can be abbreviated as LPF), and the specific design methods include:

[0119] Assuming the target BPF has a bandwidth of 380kHz and a characteristic impedance of 50Ω, a third-order fixed-K type LPF with a cutoff frequency of 380kHz and a characteristic impedance of 50Ω can be designed.

[0120] Then, combine Figure 4 As shown in (a), the capacitor CA and inductor LB in the third-order fixed-K type LPF are transformed to obtain... Figure 4 The BPF shown in (b) is an example; where the center frequency of the BPF can be 210KHz and the frequency band can be from 20KHz to 400KHz.

[0121] Of course, the design method and specific circuit structure of the filter sub-circuit are not limited to the above scope. Other structures that can realize the function of the filter sub-circuit, which are well known to those skilled in the art, are also possible and are not limited here.

[0122] 4. Third amplifier sub-circuit.

[0123] In one or more embodiments, see Figure 5 The schematic diagram of the third amplifier sub-circuit 40 shown includes: a bias voltage generation module w1, an adjustable gain amplifier module 42, a fixed gain amplifier module 43 and an output control module w2 connected in series.

[0124] The bias voltage generation module w1 is used to generate a corresponding third bias voltage signal based on the single-phase signal processed by the filter sub-circuit.

[0125] The adjustable gain amplifier module is used to: perform gain processing on the third bias voltage signal according to a preset gain factor to obtain a gain signal;

[0126] Fixed gain amplifier module 43 is used to: perform load boosting processing on the gain signal;

[0127] The output control module W2 is used to perform impedance matching on the signal processed by the fixed gain amplifier module 43.

[0128] Thus, the adjustable gain amplification module can be used to process the signal gain, and the gain can be dynamically adjusted according to actual needs, thereby meeting the needs of various application scenarios and improving design flexibility. Furthermore, the fixed gain amplification module can be used to improve the signal load capacity, thereby increasing the load capacity of the signal amplification circuit and enabling the signal amplification circuit to have low impedance and high driving capability.

[0129] In one or more embodiments, such as Figure 5As shown, the adjustable gain amplifier module 42 includes: a second operational amplifier OT2, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10, and a switch S1.

[0130] The first input terminal of the second operational amplifier OT2 is electrically connected to the first terminal of the fourteenth resistor R14 and the bias voltage generation module w1, respectively. The second input terminal of the second operational amplifier OT2 is electrically connected to the first terminals of the tenth resistor R10, the eleventh resistor R11, the twelfth resistor R12, the thirteenth resistor R13 and the seventh capacitor C7, respectively. The third input terminal of the second operational amplifier OT2 is electrically connected to the power supply terminal VIN and the first terminal of the ninth capacitor C9, respectively. The fourth input terminal of the second operational amplifier OT2 is electrically connected to the ground terminal GND and the first terminal of the tenth capacitor C10, respectively. The fifth input terminal of the second operational amplifier OT2 is electrically connected to the second terminal of the tenth capacitor C10, respectively. The output terminal of the second operational amplifier OT2 is electrically connected to the second terminal of the tenth resistor R10, the second terminal of the seventh capacitor C7 and the fixed gain amplification module 43, respectively.

[0131] The second terminal of the eleventh resistor R11 and the second terminal of the twelfth resistor R12 are both electrically connected to the first control terminal of switch S1.

[0132] The second terminal of the thirteenth resistor R13 is electrically connected to the second control terminal of switch S1;

[0133] The second end of the fourteenth resistor R14 is electrically connected to the ground terminal GND and the bias voltage generation module w1, respectively.

[0134] The eighth capacitor C8 is electrically connected between the ground terminal GND and the third control terminal of switch S1;

[0135] The second terminal of the ninth capacitor C9 is electrically connected to the ground terminal GND;

[0136] The fourth control terminal of switch S1 is left floating.

[0137] In this circuit, the tenth resistor R10 serves as a feedback resistor and can be paired with the eleventh resistor R11, the twelfth resistor R12, and the thirteenth resistor R13 to control the gain amplification factor of the third amplification sub-circuit 40. In one or more embodiments, the switch S1 has four control terminals. When the third control terminal 3 is connected to the first control terminal 1, the tenth resistor R10, the eleventh resistor R11, and the twelfth resistor R12 affect the gain amplification factor, which can be obtained through in-phase proportional calculation. When the third control terminal 3 is connected to the second control terminal 2, the tenth resistor R10 and the thirteenth resistor R13 affect the gain amplification factor, and the obtained gain amplification factor is the ratio of the resistance values ​​of the tenth resistor R10 and the thirteenth resistor R13. When the third control terminal 3 is connected to the fourth control terminal 4, the adjustable gain amplification module 42 has no gain amplification function and can be used as a follower circuit. Therefore, by controlling the switch S1, the gain amplification factor of the third amplification sub-circuit 40 can be controlled, for example, but not limited to, changes of 100 times, 10 times, and 1 times.

[0138] The fourteenth resistor R14 can be used as a balancing resistor at the first input terminal of the second operational amplifier OT2 to reduce the impact of offset current on the output; the seventh capacitor C7 can be used as a compensation capacitor to prevent the second operational amplifier OT2 from self-oscillating, thereby ensuring that the second operational amplifier OT2 can work normally and stably; the ninth capacitor C9 can be used as a filter capacitor to filter out high-frequency noise; the tenth capacitor C10 can be used as an internal frequency compensation node capacitor; and the eighth capacitor C8 can be used as a filter capacitor.

[0139] In one or more embodiments, the specific structure of the adjustable gain amplification module 42 is not limited to... Figure 5 As shown, it can also be configured with other structures that can realize the function of the adjustable gain amplification module 42, which are not limited here.

[0140] In one or more embodiments, the fixed gain amplifier module 43 includes a follower circuit.

[0141] Among them, the follower circuit can be as follows Figure 5 As shown, it includes a thirteenth capacitor C13 and a third operational amplifier OT3, and the connection method of the thirteenth capacitor C13 and the third operational amplifier OT3 can be as follows: Figure 5 As shown, it will not be elaborated further here.

[0142] Thus, based on the follower circuit, the gain signal output by the adjustable gain amplifier module 42 can be followed and the load-carrying capacity can be improved, thereby reducing the impedance of the third amplifier sub-circuit 40 and improving the load-carrying capacity and high driving capacity of the third amplifier sub-circuit 40 and even the signal amplifier circuit.

[0143] In one or more embodiments, the specific structure of the bias voltage generation module w1 is as described above, and will not be repeated.

[0144] In one or more embodiments, the specific structure of the output control module w2 is as described above, and will not be repeated.

[0145] In summary, by setting the third amplifier sub-circuit, the gain of the third amplifier sub-circuit can be adjusted according to actual needs to meet the requirements of different application scenarios; furthermore, the load-carrying capacity of the third amplifier sub-circuit can be improved, giving it a higher driving capability, thus making the third amplifier sub-circuit have the characteristics of adjustable gain, low output resistance, and high driving capability.

[0146] 5. Other structures.

[0147] The above description mentions a power supply terminal, which can be electrically connected to a power supply device, allowing the power supply device to provide a power signal. If the current value corresponding to the power signal provided by the power supply device is large, it may cause the first to third amplification sub-circuits to burn out. To prevent such an accident, in one or more embodiments, a power management sub-circuit can be provided between the power supply device and the power supply terminal. This power management sub-circuit is used for:

[0148] The power management sub-circuit is used to: restrict the transmission of the power signal to the power supply terminal when the current value corresponding to the power signal provided by the power supply device is greater than a threshold; and transmit the power signal to the power supply terminal when the current value corresponding to the power signal provided by the power supply device is not greater than the threshold.

[0149] In this way, the power management sub-circuit can prevent damage to each amplification sub-circuit caused by excessive current value corresponding to the power signal being directly transmitted to each amplification sub-circuit, thereby protecting each amplification sub-circuit and improving the reliability and safety of the signal amplification circuit.

[0150] In one or more embodiments, see Figure 6 The schematic diagram of the power management sub-circuit 50 shown includes: a current limiting protection module 51, a transmission module 52, and a third filtering module 53.

[0151] The current limiting protection module 51 is electrically connected to the power supply device m1 and the transmission module 52 respectively. The transmission module 52 is also electrically connected to the third filter module 53.

[0152] The current limiting protection module 51 is used to: restrict the transmission of the power signal to the transmission module 52 when the current value corresponding to the power signal provided by the power supply device m1 is greater than the threshold; and to transmit the power signal to the transmission module 52 when the current value corresponding to the power signal provided by the power supply device m1 is not greater than the threshold.

[0153] Transmission module 52 is used to: transmit the received power signal to the power supply terminal VIN;

[0154] The third filtering module 53 is used to filter the signal output by the transmission module 52.

[0155] Thus, when the current value corresponding to the power signal provided by the power supply device is greater than the threshold, it indicates that the current provided by the power supply device is large. At this time, the current limiting protection module restricts the transmission of the power signal to the transmission module, preventing the power signal from being transmitted to each amplifier sub-circuit, thereby achieving current limiting protection for each amplifier sub-circuit.

[0156] In one or more embodiments, such as Figure 6 As shown, the current limiting protection module 51 includes: a current limiting fuse structure G1 and a Schottky diode D3;

[0157] The first terminal of the current limiting fuse structure G1 is electrically connected to the power supply device m1, and the second terminal of the current limiting fuse structure G1 is electrically connected to the negative terminal of the Schottky diode D3 and the transmission module 52, respectively.

[0158] The positive terminal of Schottky diode D3 is electrically connected to ground terminal GND and transmission module 52, respectively.

[0159] Among them, the current-limiting fuse structure G1 can be, but is not limited to, a self-resetting current-limiting fuse. When the current value of the power signal is greater than the threshold, the current-limiting fuse structure G1 is in a high-resistance state, thereby limiting the current flow. The Schottky diode D3 can absorb the surge caused by the transient large current and protect the subsequent circuit from damage.

[0160] In one or more embodiments, the specific structure of the current limiting protection module 51 is not limited to... Figure 6 As shown, it can also be configured with other structures that can realize the function of current limiting protection module 51, which are not limited here.

[0161] In one or more embodiments, such as Figure 6 As shown, the third filter module 53 includes: a thirteenth capacitor C13 and an eighteenth resistor R18;

[0162] The first terminal of the thirteenth capacitor C13 is electrically connected to the ground terminal GND, and the second terminal of the thirteenth capacitor C13 is electrically connected to the first terminal of the eighteenth resistor R18.

[0163] The second end of the eighteenth resistor R18 is electrically connected to the power supply terminal VIN and the transmission module 52, respectively.

[0164] Among them, the thirteenth capacitor C13 and the eighteenth resistor R18 can filter the power signal output by the transmission module 52 to ensure the stability of the power signal.

[0165] In one or more embodiments, the specific structure of the third filtering module 53 is not limited to... Figure 6 As shown, it can also be configured with other structures that can realize the function of the third filter module 53, which are not limited here.

[0166] In one or more embodiments, such as Figure 6 As shown, the transmission module 52 includes: a relay G2.

[0167] The specific structure of relay G2, and the connection relationship between each pin of relay G2 and the third filter module 53 and the current limiting protection module 51, can be described as follows: Figure 6 As shown, it will not be elaborated further here.

[0168] exist Figure 6 In the process, when the current value corresponding to the power signal provided by the power supply device m1 is not greater than the threshold, the power signal enters the relay G2 through the current limiting fuse structure G1. At this time, pins 3 and 4 of the relay G2 are closed, and pins 7 and 8 are closed, so that the power signal is transmitted to the power supply terminal VIN through pins 7 and 8.

[0169] When the current value corresponding to the power signal provided by the power supply device m1 is greater than the threshold, the current limiting fuse structure G1 restricts the power signal from passing through. At this time, it can be considered that the relay G2 has no power signal input, so that pins 2 and 3, pins 8 and 9 in the relay G2 are closed, and the power supply VIN has no signal output.

[0170] When the power supply device m1 does not provide a power signal, the relay G2 will still have pins 2 and 3 closed, pins 8 and 9 closed, and the power supply VIN will not output a signal.

[0171] In this way, under the action of relay G2, the power signal can be transmitted to the power supply terminal VIN, and the current value corresponding to the output power signal can be avoided to be too large, thus protecting each amplifier sub-circuit.

[0172] In one or more embodiments, the specific structure of the transmission module 52 is not limited to... Figure 6 As shown, it can also be configured with other structures that can realize the function of transmission module 52, which are not limited here.

[0173] In summary, by configuring the three amplification sub-circuits, the filtering sub-circuit, and the power management sub-circuit, weak electrical signals can be amplified, the gain can be dynamically adjusted, the load capacity can be improved, and the safety and reliability of the signal amplification circuit can be enhanced. Thus, the signal amplification circuit can have more comprehensive functions and a wider range of applications.

[0174] Based on the same inventive concept, embodiments of the present invention provide a leakage detection device, such as... Figure 7 As shown, it includes: a sensor 710, a signal amplification circuit 720, and a processor 730; the signal amplification circuit 720 is the same as the signal amplification circuit provided in the embodiments of the present invention.

[0175] Sensor 710 is used to: collect the vibration frequency when the container under test vibrates and convert it into a corresponding electrical signal;

[0176] The signal amplifier circuit 720 is used to amplify the converted electrical signal to obtain an amplified signal;

[0177] The processor 730 is used to detect whether a leak has occurred in the container to be tested, based on the amplified signal.

[0178] Thus, when the container under test generates elastic vibration by forming an acoustic emission source, the sensor can detect the vibration frequency of the elastic vibration. After amplification by the signal amplification circuit, the processor can detect whether the container under test has leaked. Therefore, the leakage of the container under test can be detected based on acoustic emission technology, realizing non-destructive testing and avoiding secondary damage to the container under test.

[0179] Furthermore, by processing the electrical signal through a signal amplification circuit, three-stage amplification of the electrical signal can be achieved, thereby effectively amplifying the weak electrical signal. This allows the processor to determine whether leakage has occurred in the object to be detected based on the amplified signal (i.e., the amplified signal), thus realizing the detection of micro-leakage and improving detection sensitivity.

[0180] In one or more embodiments, when selecting a sensor, the selection can be based on factors such as the characteristics of the acoustic emission signal of the metal material and the frequency range of the acoustic emission signal during leakage, so that the sensor can collect the vibration frequency of the container to be detected.

[0181] In one or more embodiments, due to the presence of various electromagnetic waves in the air, a shielding box can be installed to prevent these electromagnetic waves from interfering with the signal amplification circuit, such as... Figure 8The shielding box 740 shown can house the signal amplification circuit 720. The shielding box 740 can shield external electromagnetic waves, thereby improving the signal-to-noise ratio of the signal amplification circuit 720.

[0182] In one or more embodiments, such as Figure 8 As shown, the shielding box 740 has:

[0183] The base 741 has a first mounting hole t1, through which the signal amplification circuit 720 can be mounted and positioned in the base 741 to facilitate movement of the signal amplification circuit 720; furthermore, the base 741 has a grounding terminal. Figure 8 (not shown in the image), the signal amplification circuit 720 can be electrically connected to the ground terminal through the base 741;

[0184] The cover (not shown in the figure) can be fixedly connected to the base 741 through the second mounting hole t2. The cover and the base 741 form a cavity with an internal space. When the signal amplification circuit 720 is placed in the cavity, it can shield external electromagnetic interference.

[0185] The input / output interface 742 has a shielding layer to prevent external electromagnetic waves from interfering with the input and output signals; the input / output interface 742 may, but is not limited to, use a low-noise BNC interface.

[0186] The input signal selection switch 743 can control whether a signal is input to the signal amplifier circuit 720, so as to control whether the signal amplifier circuit 720 works. Therefore, the input signal selection switch 743 can also be understood as the start switch of the signal amplifier circuit 720.

[0187] Gain selection switch 744 can be connected to the switch in the adjustable gain amplifier module mentioned above, so that the user can select the gain amplification factor;

[0188] And other structures.

[0189] Furthermore, the size of the shielding box can be set according to factors such as the size of the signal amplification circuit, and is not limited here.

[0190] In one or more embodiments, before determining whether a leak has occurred in the sensor to be detected, the processor may first acquire the amplified signal output by the signal amplification circuit, and combine it with... Figure 9 The block diagram of the signal acquisition program shown uses DMA (Direct Memory Access) interrupt control for signal acquisition; combined with... Figure 9The block diagram shown illustrates the specific signal acquisition process, which includes:

[0191] Step 1.1: The acquisition unit acquires the input amplified signal according to the preset sampling frequency and transmits it to the DMA interrupt program through the drive unit;

[0192] Step 1.2: The detection unit detects the function key selected by the user and assigns a value to work_state;

[0193] The function keys may include:

[0194] When the leak detection device includes a display, button 1 can correspond to the timing information of the data displayed on the display; at this time, the corresponding work_state = 1;

[0195] When the leakage detection device includes a display, button 2 can display the frequency domain information of the data on the display; at this time, the corresponding work_state = 2;

[0196] Button 3 enables remote interaction; in this case, work_state = 3.

[0197] Button 4 can be used for data storage to facilitate data storage on the SD memory card; at this time, the corresponding work_state = 4.

[0198] Of course, function keys are not limited to the four mentioned above; they can also include keys used to perform other functions. This is just an example of these four types, and no further limitation is made here.

[0199] For example, in step 1.2, assuming that the user selects button 2, the value of work_state can be assigned to 2.

[0200] Step 1.3: Based on the correspondence between the work_state value and the preset function, execute the operation of the preset function corresponding to the work_state after the value was assigned in Step 1.2;

[0201] Step 1.4: Determine if the user chooses to exit; if yes, exit and return to step 1.1; if no, return to step 1.3.

[0202] The user can choose to exit in the following ways:

[0203] An exit button is specifically provided for user convenience;

[0204] Alternatively, an exit function can be added to a button in addition to the original button; for example, when the exit function is added to button 3, pressing button 3 once indicates remote interaction, and pressing button 3 twice indicates exit.

[0205] Furthermore, in Figure 9 In this system, when remote interaction is selected, data can be directly transmitted to the remote data debugging terminal via data transmission; when data storage is selected, the data is first stored in the SD memory card and then indirectly transmitted to the remote data debugging terminal, thus realizing data storage and interaction.

[0206] In one or more embodiments, the processor, when performing a leak determination, may specifically include:

[0207] Step 2.1: Based on the preset sampling frequency, perform conversion processing on the amplified signal to obtain the frequency domain distribution map;

[0208] In the frequency domain distribution diagram, the horizontal axis represents frequency, and the vertical axis represents the intensity of the corresponding frequency; the distribution curve can be obtained through the discrete points in the frequency domain distribution diagram.

[0209] Furthermore, when performing conversion processing on the amplified signal, Fourier transform can be used, but is not limited to.

[0210] Step 2.2: Determine the integral area of ​​the curve within the reference frequency range in the frequency domain distribution diagram to obtain the reference area;

[0211] The frequencies corresponding to leaks with different aperture sizes are different, and there is a certain correspondence between the two. Therefore, a reference frequency can be selected based on this correspondence so that the aperture size of the leak can be determined at the same time as whether the container under test has leaked.

[0212] Step 2.3: Determine whether the container to be tested has leaked based on the probability of the relationship between the reference area and the preset area within the preset number of judgments.

[0213] Thus, since the amplified signal has a high signal-to-noise ratio and a high gain after being processed by the signal amplification circuit, a lot of interference can be removed. Based on this amplified signal, the accuracy of the judgment can be effectively improved. Furthermore, when the judgment is based on the probability of the relationship between the size of the reference area and the preset area within a preset number of judgments, the accuracy of the judgment result can be further improved and the probability of misjudgment can be reduced.

[0214] In one or more embodiments, the specific implementation of step 2.3 above may include:

[0215] When the reference area is greater than the preset area, increment the first count value by one; when the reference area is not greater than the preset area, increment the second count value by one.

[0216] If, within the preset number of judgments, the first count value is greater than the second count value, it is determined that the container under test has leaked.

[0217] If the first count value is not greater than the second count value within the preset number of judgments, it is determined that the container under test has not leaked.

[0218] Thus, within a preset number of judgments, if the first count value is greater than the second count value, it indicates that the probability of leakage is relatively high within a limited number of judgments, and the container under test can be considered to have leaked; if the first count value is not greater than the second count value, it indicates that the probability of leakage is low within a limited number of judgments, and there may be a misjudgment, so the container under test can be considered not to have leaked. This can effectively improve the accuracy of the judgment results and reduce the chance of misjudgment.

[0219] The leakage determination process will be explained below with reference to specific embodiments.

[0220] Combination Figure 10 The flowchart shown.

[0221] S1001. Acquire the amplified signal and perform conversion processing on the acquired amplified signal to obtain the frequency domain distribution map;

[0222] At the initial moment, the current number of judgments is set to 0, and both the first and second count values ​​are set to 0.

[0223] S1002. Determine the integral area of ​​the curve within the reference frequency range in the frequency domain distribution diagram to obtain the reference area;

[0224] S1003. Determine if the current number of judgments is equal to the preset number of judgments; if not, proceed to S1004; if yes, proceed to S1007.

[0225] S1004. Determine if the reference area is greater than the preset area; if not, proceed to S1005; if yes, proceed to S1006.

[0226] S1005, Increment the second count by 1, and increment the current number of judgments by 1; Return to S1001;

[0227] S1006, Increment the first count value by 1, and increment the current number of judgments by 1; Return to S1001;

[0228] S1007. Determine if the first count value is greater than the second count value; if not, proceed to S1008; if yes, proceed to S1009.

[0229] S1008. Confirm that the container under test has not leaked; end the process.

[0230] S1009. It has been determined that the container to be tested has leaked.

[0231] In one or more embodiments, the determination of whether the current number of determinations is equal to the preset number of determinations in S1003 can also be performed after the amplified signal is acquired. In this way, when the current number of determinations is equal to the preset number of determinations, there is no need to perform conversion processing and determine the reference area, which can reduce the amount of calculation and reduce the power consumption of the device.

[0232] In one or more embodiments, when a container under test experiences a slight leak, the time-domain waveform is not obvious, but there is a significant change in a specific frequency band in the frequency domain. Therefore, by setting a suitable preset area based on the size of a certain frequency band in the frequency domain, it can be determined whether the container under test has a leak. Since the working environment of the field equipment may be subject to interference, to improve the accuracy of the judgment, the reference area within the reference frequency range is compared with the preset area multiple times. If the reference area is larger than the preset area, a leak exists; if it is smaller than the preset area, there is no leak. After multiple comparisons, the case with the highest number of comparisons is taken as the judgment result, thereby improving the accuracy of the judgment result.

[0233] In one or more embodiments, the function of a leak detection device can be realized by the combined use of a sensor, a signal amplification circuit, and a processor. At the same time, based on the structure of the signal amplification circuit and the small size and light weight of the sensor, the size and weight of the leak detection device can be effectively reduced, realizing the portable design of the leak detection device.

[0234] Based on the same inventive concept, this invention provides a leakage detection method. The implementation principle of this detection method is similar to that of the aforementioned leakage detection device. For specific implementation methods of this detection method, please refer to the specific embodiments of the aforementioned leakage detection device. Repeated details will not be repeated.

[0235] In one or more embodiments, the leakage detection method provided by the embodiments of the present invention, such as Figure 11 As shown, it includes:

[0236] S1101. Obtain the vibration frequency when the container under test vibrates, and convert the vibration frequency into a corresponding electrical signal;

[0237] S1102. Amplify the electrical signal to obtain an amplified signal;

[0238] S1103. Based on the preset sampling frequency, the amplified signal is converted and processed to obtain the frequency domain distribution map;

[0239] S1104. Determine the integral area of ​​the curve within the reference frequency range in the frequency domain distribution diagram to obtain the reference area;

[0240] S1105. Based on the probability of the relationship between the reference area and the preset area occurring within a preset number of judgments, determine whether the container to be tested has leaked.

[0241] The amplified signal in step S1102 above is obtained in the following way:

[0242] The electrical signal is processed to improve the signal-to-noise ratio and perform differential processing to obtain a biphase signal;

[0243] The two-phase signal is subjected to operational amplification and single-phase to two-phase conversion to obtain a single-phase signal;

[0244] Filtering of single-phase signals;

[0245] The filtered single-phase signal is amplified by performing gain processing and load boosting processing to output an amplified signal.

[0246] In one or more embodiments, determining whether the container to be detected has leaked based on the probability of the relationship between the size of the reference area and the preset area occurring within a preset number of judgments includes:

[0247] When the reference area is greater than the preset area, increment the first count value by one; when the reference area is not greater than the preset area, increment the second count value by one.

[0248] If, within the preset number of judgments, the first count value is greater than the second count value, it is determined that the container under test has leaked.

[0249] If the first count value is not greater than the second count value within the preset number of judgments, it is determined that the container under test has not leaked.

[0250] In summary, the technical solutions provided by the embodiments of the present invention have the following advantages:

[0251] 1. A signal amplification circuit for acoustic emission designed for weak signals, capable of providing high gain amplification and adjustable gain according to actual needs. To improve noise immunity, differential amplification, shielding, and filtering sub-circuits are employed, giving the signal amplification circuit high noise immunity.

[0252] 2. Leakage detection method: The system collects data multiple times, compares the results multiple times, and takes the result with the highest number of comparisons as the output result. The maximum likelihood method is used to improve the accuracy of the leakage detection device.

[0253] 3. No disassembly of the container to be tested is required. Testing can be performed while the container is in operation. Simply fix the sensor to the outer wall of the container to be tested to achieve non-destructive testing. As a portable device, it only requires a small 12V battery for power supply, so it can be used in places where power is unavailable. It is easy to operate and can quickly and in real time provide test results.

[0254] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A leak detection device, characterized in that, include: Sensors, signal amplification circuits, and processors; The sensor is used to: collect the vibration frequency of the container being tested when it vibrates and convert it into a corresponding electrical signal; The signal amplification circuit is used to: amplify the converted electrical signal to obtain an amplified signal; The processor is used to: detect whether the container to be tested has leaked based on the amplified signal; The signal amplification circuit includes: a first amplification sub-circuit, a second amplification sub-circuit, a filter sub-circuit, and a third amplification sub-circuit; The first amplification sub-circuit is used to: perform signal-to-noise ratio enhancement processing and differential processing on the electrical signal to obtain a biphase signal; The second amplifier sub-circuit is used to: perform operational amplification and single-to-two-phase conversion processing on the two-phase signal to obtain a single-phase signal; The filter sub-circuit is used to: filter the single-phase signal; The third amplifier sub-circuit is used to: perform gain processing and load boosting processing on the filtered single-phase signal and then output the amplified signal; The processor is specifically used to: convert the amplified signal based on a preset sampling frequency to obtain a frequency domain distribution map; determine the integral area of ​​the curve within a reference frequency range in the frequency domain distribution map to obtain a reference area; and determine whether the container to be detected has leaked based on the probability of the relationship between the reference area and the preset area occurring within a preset number of judgments.

2. The leakage detection device as described in claim 1, characterized in that, The first amplification sub-circuit includes: a differential processing module, a signal-to-noise ratio improvement module, a bias voltage generation module, and a first filtering module; There are two of each of the signal-to-noise ratio (SNR) enhancement module and the bias voltage generation module. The SNR enhancement module and the bias voltage generation module are sequentially arranged between the first input terminal of the first amplification sub-circuit and the differential processing module, and between the second input terminal of the first amplification sub-circuit and the differential processing module. The first filtering module is electrically connected to the differential processing module and the power supply terminal, respectively. The signal-to-noise ratio enhancement module is used to: perform noise reduction, impedance matching, and clamping processing on the electrical signal before inputting it to the bias voltage generation module; The bias voltage generation module is used to: generate a corresponding first bias voltage signal based on the signal processed by the signal-to-noise ratio improvement module; The first filtering module is used to: filter the power signal provided by the power supply terminal and then output it to the differential processing module; The differential processing module is used to: perform mapping processing on the first bias voltage signal and the signal output by the first filtering module, and perform differential processing on the mapped signal to obtain the biphase signal.

3. The leakage detection device as described in claim 2, characterized in that, The differential processing module includes: a first transistor and a second transistor symmetrically arranged, a first resistor, a second resistor, a third resistor, a fourth resistor, and a constant current diode; the differential processing module has a first input terminal, a second input terminal, a first output terminal, and a second output terminal; the bases of the first transistor and the second transistor are respectively electrically connected to the two bias voltage generation modules one-to-one; the emitter of the first transistor is electrically connected to the first end of the first resistor; the collector of the first transistor is electrically connected to the first end of the second resistor and the first output terminal, respectively; the emitter of the second transistor is electrically connected to the first end of the third resistor; the collector of the second transistor is electrically connected to the first end of the fourth resistor and the second output terminal, respectively; the second ends of the first resistor and the third resistor are both electrically connected to the anode of the constant current diode; the second ends of the second resistor and the fourth resistor are both electrically connected to the power supply terminal and the first filter module; the cathode of the constant current diode is electrically connected to the ground terminal; And / or, the signal-to-noise ratio enhancement module includes: a magnetic bead, a first capacitor, a fifth resistor, and a clamping diode arranged in series.

4. The leakage detection device as described in claim 1, characterized in that, The second amplification sub-circuit includes: a bias voltage generation module, an operational amplification module, a second filtering module, and an output control module; The bias voltage generation module is located between the output terminal of the first amplification sub-circuit and the operational amplification module; the second filtering module is located between the power supply terminal and the operational amplification module; the output control module is located between the output terminal of the operational amplification module and the filtering sub-circuit. The bias voltage generation module is used to: generate a corresponding second bias voltage signal based on the biphase signal; The second filtering module is used to: filter the power signal provided by the power supply terminal and then output it to the operational amplifier module; The operational amplifier module is used to: activate the operational amplifier function according to the second bias voltage signal, and when the operational amplifier function is activated, perform the operational amplification processing and the single-phase to dual-phase conversion processing on the second bias voltage signal to obtain the single-phase signal; The output control module is used to perform impedance matching processing on the single-phase signal.

5. The leakage detection device as described in claim 4, characterized in that, The operational amplifier module includes: a first operational amplifier, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, and a fourth capacitor; the first input terminal of the first operational amplifier is electrically connected to the first terminals of the sixth resistor, the seventh resistor, and the fourth capacitor, respectively; the second input terminal of the first operational amplifier is electrically connected to the first terminals of the eighth resistor and the ninth resistor, respectively; the third input terminal of the first operational amplifier is electrically connected to the second filter module; the fourth input terminal of the first operational amplifier is electrically connected to ground; and the output terminal of the first operational amplifier is electrically connected to the second terminals of the sixth resistor and the fourth capacitor, respectively; there are two bias voltage generation modules, and the second terminals of the seventh resistor and the eighth resistor are electrically connected to the two bias voltage generation modules one-to-one; the second terminal of the ninth resistor is electrically connected to the ground.

6. The leakage detection device as described in claim 1, characterized in that, The third amplifier sub-circuit includes: a bias voltage generation module, an adjustable gain amplifier module, a fixed gain amplifier module, and an output control module connected in series. The bias voltage generation module is used to generate a corresponding third bias voltage signal based on the single-phase signal processed by the filter sub-circuit. The adjustable gain amplification module is used to: perform the gain processing on the third bias voltage signal according to a preset gain factor to obtain a gain signal; The fixed gain amplification module is used to: perform the load boosting process on the gain signal; The output control module is used to perform impedance matching processing on the signal processed by the fixed gain amplification module.

7. The leakage detection device as described in claim 6, characterized in that, The adjustable gain amplification module includes: a second operational amplifier, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, and a switch; The first input terminal of the second operational amplifier is electrically connected to the first terminal of the fourteenth resistor and the bias voltage generation module, respectively. The second input terminal of the second operational amplifier is electrically connected to the first terminals of the tenth resistor, the eleventh resistor, the twelfth resistor, the thirteenth resistor, and the seventh capacitor, respectively. The third input terminal of the second operational amplifier is electrically connected to the power supply terminal and the first terminal of the ninth capacitor, respectively. The fourth input terminal of the second operational amplifier is electrically connected to the ground terminal and the first terminal of the tenth capacitor, respectively. The fifth input terminal of the second operational amplifier is electrically connected to the second terminal of the tenth capacitor, respectively. The output terminal of the second operational amplifier is electrically connected to the second terminal of the tenth resistor, the second terminal of the seventh capacitor, and the fixed gain amplification module, respectively. The second end of the eleventh resistor and the second end of the twelfth resistor are both electrically connected to the first control terminal of the switch; The second terminal of the thirteenth resistor is electrically connected to the second control terminal of the switch; The second end of the fourteenth resistor is electrically connected to the grounding terminal and the bias voltage generation module, respectively. The eighth capacitor is electrically connected between the ground terminal and the third control terminal of the switch; The second terminal of the ninth capacitor is electrically connected to the ground terminal; The fourth control terminal of the switch is left floating.

8. The leakage detection device according to any one of claims 2-4, characterized in that, It also includes a power management sub-circuit, which is located between the power supply terminal and the power supply device; The power management sub-circuit is used to: restrict the transmission of the power signal to the power supply terminal when the current value corresponding to the power signal provided by the power supply device is greater than a threshold; and transmit the power signal to the power supply terminal when the current value corresponding to the power signal provided by the power supply device is not greater than the threshold.

9. The leakage detection device as described in claim 8, characterized in that, The power management sub-circuit includes: a current limiting protection module, a transmission module, and a third filtering module; The current limiting protection module is electrically connected to the power supply device and the transmission module respectively, and the transmission module is also electrically connected to the third filtering module; The current limiting protection module is used to: restrict the transmission of the power signal to the transmission module when the current value corresponding to the power signal provided by the power supply device is greater than the threshold; and to transmit the power signal to the transmission module when the current value corresponding to the power signal provided by the power supply device is not greater than the threshold. The transmission module is used to: transmit the received power signal to the power supply terminal; The third filtering module is used to filter the signal output by the transmission module.

10. The leakage detection device as described in claim 9, characterized in that, The current limiting protection module includes: a current limiting fuse structure and a Schottky diode; The first end of the current-limiting fuse structure is electrically connected to the power supply device, and the second end of the current-limiting fuse structure is electrically connected to the negative terminal of the Schottky diode and the transmission module, respectively. The positive terminal of the Schottky diode is electrically connected to both the ground terminal and the transmission module.

11. The leakage detection device as described in claim 1, characterized in that, The processor is specifically used for: When the reference area is greater than the preset area, the first count value is incremented by one; when the reference area is not greater than the preset area, the second count value is incremented by one. If, within the preset number of judgments, the first count value is greater than the second count value, it is determined that the container to be detected has leaked. If the first count value is not greater than the second count value within the preset number of judgments, it is determined that the container to be tested has not leaked.

12. A leakage detection method, characterized in that, include: The vibration frequency of the container under test is obtained when it vibrates, and the vibration frequency is converted into a corresponding electrical signal; The electrical signal is amplified to obtain an amplified signal; Based on a preset sampling frequency, the amplified signal is converted to obtain a frequency domain distribution map; The integral area of ​​the curve within the reference frequency range in the frequency domain distribution diagram is determined to obtain the reference area; Based on the probability of the relationship between the reference area and the preset area occurring within a preset number of judgments, it is determined whether the container to be detected has leaked; The amplified signal is obtained in the following way: The electrical signal is subjected to signal-to-noise ratio enhancement and differential processing to obtain a biphase signal; The two-phase signal is subjected to operational amplification and single-phase to two-phase conversion to obtain a single-phase signal; The single-phase signal is filtered. The amplified signal is output after the filtered single-phase signal undergoes gain processing and load boosting processing.

13. The leakage detection method as described in claim 12, characterized in that, Based on the probability of the relationship between the reference area and the preset area occurring within a preset number of judgments, determine whether the container to be detected has leaked, including: When the reference area is greater than the preset area, the first count value is incremented by one; when the reference area is not greater than the preset area, the second count value is incremented by one. If, within the preset number of judgments, the first count value is greater than the second count value, it is determined that the container to be detected has leaked. If the first count value is not greater than the second count value within the preset number of judgments, it is determined that the container to be tested has not leaked.

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