Laser multi-gas micro-leak detection method, system and medium

Abstract

The present invention provides a laser multi-gas micro-leak detection method, system and medium, the method comprising: using the real-time temperature value T and a pre-configured ambient temperature relationship model to determine the target operating temperature T of the laser in the laser gas sensor 实1 , dynamically adjust the laser; determine the response value I and the absorption peak real-time position P corresponding to the first target gas 实1 , determine whether the response value I is greater than the first threshold V1; if so, determine the absorption peak real-time position P 实1 Is it within the preset absorption peak range of the first target gas? If so, use the calibration curve of the first target gas to obtain the concentration of the first target gas; when the response value II corresponding to the second target gas is greater than the second threshold V2, use the calibration curve of the second target gas to obtain the concentration of the second target gas; if not, dynamically adjust the laser and then determine the response value II and the real-time position P of the absorption peak corresponding to the second target gas. 实2 , judge whether the response value II is greater than the second threshold value V2, if it is greater than the second threshold value V2, then at the absorption peak real-time position P 实2 When in the preset absorption peak interval, the concentration of the second target gas is obtained using the calibration curve of the second target gas.

Description

Technical Field

[0001] The present invention relates to the technical field of laser gas detection, and in particular to a laser multi-gas micro-leakage detection method, system and medium. Background Art

[0002] Laser gas sensors use laser spectroscopy to detect target gas concentrations in an environment. Temperature fluctuations can cause the laser's output wavelength to blueshift or redshift, affecting gas detection accuracy. It's important to note that blueshift and redshift are physical phenomena that describe the shift of spectral lines toward shorter wavelengths (the blue end) or longer wavelengths (the red end). This phenomenon is primarily due to temperature-induced changes in the thermal expansion coefficient of the laser's internal material and the refractive index within the optical cavity, which in turn alter the laser's wavelength.

[0003] It should be noted that the environment being measured may contain multiple types of target gases. For gas detection, lasers are typically used to determine the concentration of a specific gas by measuring its absorption of laser light. Each gas has its own unique absorption spectrum, meaning it absorbs lasers of different wavelengths to varying degrees. Therefore, if the laser's output wavelength shifts due to temperature changes, it may no longer accurately correspond to the target gas's absorption peak, resulting in a decrease in gas detection accuracy. Therefore, it is necessary to take measures to minimize the impact of ambient temperature changes on the laser's output wavelength, especially in complex environments where multiple gas concentrations need to be measured simultaneously.

[0004] It should also be noted that, since there may be multiple types of target gases in the environment, it is particularly important to design a detection device that can measure multiple types of gases at the same time. This not only helps users to understand the environmental conditions more comprehensively, but also provides key data support for various applications, such as industrial production, environmental monitoring, safety testing, etc.; although the multi-parameter gas detectors in the prior art can measure and monitor multiple gas parameters at the same time, these devices usually contain multiple lasers, one laser corresponding to one type of target gas; for example, the Chinese patent application number CN202321286801.X discloses a methane and ethane detector based on the TDLAS principle, including a methane laser and an ethane laser arranged on a circuit board. The light beam emitted by the methane laser and the light beam emitted by the ethane laser are coupled by a beam combiner and enter the optical path cell, thereby simultaneously measuring the methane and ethane contents based on the TDLAS principle. Therefore, the existing multi-parameter gas detectors usually detect the concentration of each gas separately, which makes the entire device structure complex and costly.

[0005] Therefore, it is very necessary to design a detection device with a simple structure and suitable for measuring the concentrations of multiple gases at the same time.

[0006] In order to solve the above problems, people have been seeking an ideal technical solution. Summary of the Invention

[0007] Based on this, it is necessary to provide a laser multi-gas micro-leak detection method, system and medium to address the above technical problems.

[0008] To achieve the above-mentioned object, the present invention provides a laser multi-gas micro-leak detection method in a first aspect, which comprises: determining a real-time temperature value T in an optical cavity of a laser gas sensor; determining a target operating temperature T of the laser in the laser gas sensor by using the real-time temperature value T and a pre-configured ambient temperature relationship model; 实1 ; Wherein, the ambient temperature relationship model refers to the relationship model between the real-time temperature value in the optical cavity and the target operating temperature of the laser;

[0009] The target operating temperature T 实1 As a benchmark, the laser is dynamically adjusted; the response value I and the absorption peak real-time position P corresponding to the first target gas are determined. 实1 , judging whether the response value I is greater than a first threshold value V1;

[0010] If so, determine the real-time position of the absorption peak P 实1 Whether it is in the preset absorption peak range of the first target gas, if it is in the preset absorption peak range of the first target gas, the concentration of the first target gas is obtained by using the calibration curve of the first target gas; based on the real-time position P of the absorption peak corresponding to the first target gas 实1 and the relative position difference of the absorption peaks between the two target gases, determining the absorption peak position of the second target gas to determine the response value II corresponding to the second target gas, and when the response value II corresponding to the second target gas is greater than the second threshold value V2, using the calibration curve of the second target gas to obtain the concentration of the second target gas;

[0011] If not, the laser is adjusted dynamically, and the response value II and the absorption peak real-time position P corresponding to the second target gas are determined. 实2 , judge whether the response value II is greater than the second threshold value V2, if it is greater than the second threshold value V2, then at the absorption peak real-time position P 实2 When the second target gas is in the preset absorption peak interval, the concentration of the second target gas is obtained using the calibration curve of the second target gas.

[0012] To achieve the above-mentioned objectives, the second aspect of the present invention provides a laser multi-gas micro-leak detection system, which includes a processor and a laser drive control circuit, a signal processing circuit and a temperature sensor connected to the processor, and also includes a memory for storing computer programs. The processor is used to implement the above-mentioned laser multi-gas micro-leak detection method when executing the program stored in the memory.

[0013] To achieve the above objectives, the third aspect of the present invention provides a readable storage medium having instructions stored thereon, which, when executed by one or more processors, enable the processors to execute the laser multi-gas micro-leak detection method as described above.

[0014] The beneficial effects of the present invention are:

[0015] The present invention first uses a pre-configured ambient temperature relationship model to dynamically adjust the operating temperature of the laser. Then, based on whether a first target gas is present in the optical cavity of the laser gas sensor, different strategies are selected to dynamically adjust the output wavelength of the laser, so that the output wavelength of the laser is adapted to the environment to be measured. Regardless of whether the first target gas is present in the environment to be measured, the concentration of the target gas can be quickly and accurately detected dynamically. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the process of the laser multi-gas micro-leak detection method of the present invention. Figure 1 ;

[0017] Figure 2 This is a schematic diagram of the process of the laser multi-gas micro-leak detection method of the present invention. Figure 2 ;

[0018] Figure 3 is a schematic diagram of an ambient temperature relationship model in a specific embodiment;

[0019] Figure 4 It is a schematic structural diagram of the laser multi-gas micro-leakage detection system of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described in detail below through specific implementation methods.

[0021] For ease of understanding, the interactive parties and / or terms and / or custom words involved in the present invention are first explained in conjunction with the technical solution of the present invention:

[0022] Laser gas sensor: refers to a sensor that uses laser spectroscopy technology to detect the concentration of target gas in the environment. It mainly includes a laser, an optical cavity, a photodetector, and a signal processing circuit for processing and analyzing the electrical signal output by the photodetector. The two response values ​​in the present invention are output by the same signal processing circuit, and the AD value is determined by alternating judgment and time division multiplexing to determine which target gas response value it is. The target gases include but are not limited to water vapor and ammonia, methane and ethane, etc.

[0023] Real-time temperature value T: refers to the real-time temperature value inside the optical cavity of the laser gas sensor, which is related to the current external environment of the laser gas sensor.

[0024] Ambient temperature relationship model: refers to the relationship model between the real-time temperature value in the optical cavity and the target operating temperature of the laser. This relationship model is pre-configured and pre-stored in the laser gas sensor;

[0025] Target operating temperature of the laser T 实1 : Refers to the operating temperature that matches the preset absorption peak position of the first target gas; in order to lock the output wavelength of the laser at a certain absorption peak position, a temperature control device (such as a thermostat or thermocouple) is usually used to monitor and adjust the operating temperature of the laser.

[0026] Response value: refers to the AD value output by the signal processing circuit in the laser gas sensor. The AD value corresponding to the first target gas is response value I, and the AD value corresponding to the second target gas is response value II;

[0027] First threshold V1: refers to the pre-configured threshold of the AD value corresponding to the first target gas. If the response value I is greater than the first threshold V1, it indicates that the first target gas is present in the optical cavity of the laser gas sensor. If the response value I is less than or equal to the first threshold V1, it indicates that the first target gas is not present in the optical cavity of the laser gas sensor.

[0028] The second threshold value V2 refers to the threshold value of the AD value corresponding to the pre-configured second target gas. If the response value II is greater than the second threshold value V2, it indicates that the second target gas is present in the optical cavity of the laser gas sensor. If the response value II is less than or equal to the second threshold value V2, it indicates that the second target gas is not present in the optical cavity of the laser gas sensor.

[0029] The preset absorption peak range of the first target gas refers to the pre-configured standard or theoretical absorption peak position range of the first target gas, such as the preset absorption peak range of water vapor is 1512.2 nm to 1512.8 nm, and the preset absorption peak range of methane is 1653.6 nm to 1653.8 nm;

[0030] The preset absorption peak range of the second target gas refers to the pre-configured standard or theoretical absorption peak position range of the second target gas, such as the preset absorption peak range of ammonia is 1512.0 nm to 1512.4 nm, and the preset absorption peak range of ethane is 1653.9 nm to 1654.1 nm.

[0031] It should be noted that in laser gas sensors, the absorption peak position of a gas refers to the peak position of the absorption characteristics of gas molecules to lasers of a specific wavelength. Different gas molecules have different absorption peak positions. Therefore, the relative position difference of the absorption peaks between the two target gases can be pre-stored in the laser gas sensor. Laser gas sensors can usually use phase-locked amplification technology to determine the position of the absorption peak, and the specific method will not be repeated here.

[0032] It should also be noted that the real-time position of the absorption peak will change in real time with time or other external conditions (including environmental conditions, gas concentration, temperature, pressure, and the stability of the laser source itself); therefore, the real-time position P of the absorption peak corresponding to the first target gas in the present invention is 实1 The real-time position P of the absorption peak corresponding to the second target gas 实2 , both refer to the absorption peak position after changes with time or other external conditions.

[0033] Example 1

[0034] As attached Figure 1 and attached Figure 2 As shown, this embodiment provides a specific implementation of a laser multi-gas micro-leakage detection method, which includes:

[0035] Determine the real-time temperature value T in the optical cavity of the laser gas sensor, and use the real-time temperature value T and the pre-configured ambient temperature relationship model to determine the target operating temperature T of the laser in the laser gas sensor. 实1 ; Wherein, the ambient temperature relationship model refers to the relationship model between the real-time temperature value in the optical cavity and the target operating temperature of the laser;

[0036] The target operating temperature T 实1 As a benchmark, the laser is dynamically adjusted;

[0037] Determine the response value I and the real-time position P of the absorption peak corresponding to the first target gas 实1 , judging whether the response value I is greater than a first threshold value V1;

[0038] If so, determine the real-time position of the absorption peak P 实1 Is it in the preset absorption peak range of the first target gas? If the absorption peak real-time position P 实1If the target gas is in the preset absorption peak interval of the first target gas, the concentration of the first target gas is obtained by using the calibration curve of the first target gas; based on the real-time position P of the absorption peak corresponding to the first target gas 实1 and the relative position difference of the absorption peaks between the two pre-stored target gases, determining the absorption peak position of the second target gas to determine the response value II corresponding to the second target gas, and when the response value II corresponding to the second target gas is greater than the second threshold value V2, using the calibration curve of the second target gas to obtain the concentration of the second target gas;

[0039] If not, the laser is adjusted dynamically, and the response value II and the absorption peak real-time position P corresponding to the second target gas are determined. 实2 , judge whether the response value II is greater than the second threshold value V2, if it is greater than the second threshold value V2, then at the absorption peak real-time position P 实2 When the second target gas is in the preset absorption peak interval, the concentration of the second target gas is obtained using the calibration curve of the second target gas.

[0040] In some embodiments, when the response value I is less than or equal to the first threshold value V1, the following is further performed: outputting a detection result indicating that the concentration of the first target gas is 0.

[0041] In some embodiments, when the response value II is less than or equal to the second threshold value V2, the following is further performed: outputting a detection result indicating that the concentration of the second target gas is 0.

[0042] It should be noted that when multiple types of target gases exist simultaneously in the environment to be tested, this embodiment first uses a pre-configured ambient temperature relationship model to dynamically adjust the operating temperature of the laser, and then detects whether the first target gas exists in the optical cavity based on the comparison result of the response value I and the first threshold V1. Then, different strategies are used to detect the concentrations of the two target gases. Regardless of whether the first target gas exists in the environment to be tested, the concentration of the target gas can be dynamically detected quickly and accurately.

[0043] It should also be noted that when the response value I ≤ the first threshold V1, it indicates that the first target gas does not exist in the optical cavity. At this time, the laser needs to be dynamically adjusted again to detect whether the second target gas exists in the optical cavity.

[0044] Example 2

[0045] The difference between this embodiment and embodiment 1 is that the target operating temperature T of the laser in the laser gas sensor is determined by using the temperature real-time value T and the pre-configured ambient temperature relationship model. 实1 When executing:

[0046] Obtain a pre-configured ambient temperature relationship model, wherein the ambient temperature relationship model is expressed as y=-ax2 +bx+c, y represents the target operating temperature that matches a certain temperature real-time value, x represents the real-time temperature value in the optical cavity of the laser gas sensor, a represents the first correction coefficient, b represents the second correction coefficient, and c represents the third correction coefficient;

[0047] The target operating temperature T that matches the current ambient temperature is determined by using the temperature real-time value T and the ambient temperature relationship model. 实1 .

[0048] It should be noted that when the external ambient temperature changes, the output wavelength of the laser will shift. To solve this problem, this embodiment uses a pre-configured ambient temperature relationship model to dynamically adjust the laser. First, the real-time temperature value T in the optical cavity of the laser gas sensor is determined. Then, the target operating temperature T of the laser is determined based on the real-time temperature value T and the ambient temperature relationship model. 实1 , and then dynamically adjust the laser so that the output wavelength of the laser is near the preset absorption peak position of the first target gas, and then detect the first target gas first.

[0049] In a specific embodiment, when configuring the ambient temperature relationship model, the following steps are taken:

[0050] (1) Before leaving the factory, a test system is built to test the relationship between the absorption peak position of the first target gas and the real-time temperature value T in the optical cavity. The equipment used includes a high and low temperature test chamber (used to change the current ambient temperature of the laser gas sensor), a spectrometer, a first target gas standard gas, an acquisition card and a host computer software. The acquisition card and the host computer software are used to collect data and demodulate the absorption peak position of the first target gas using a phase-locked amplification algorithm;

[0051] (2) First, set the absorption peak position of the first target gas at room temperature, change the temperature of the high and low temperature test chamber (e.g., increase the temperature from -40°C to 70°C at intervals of 10°C), and introduce the first target gas standard gas of the same concentration after each temperature stabilizes for half an hour. By changing the operating temperature of the laser, the absorption peak position of the first target gas at different ambient temperatures is close to the absorption peak position of the first target gas at room temperature;

[0052] (3) Record the operating temperature of the laser and the corresponding absorption peak position of the first target gas when the absorption peak position of the first target gas is close to the absorption peak position of the first target gas at room temperature at different temperatures in the optical cavity, as shown in the following table:

[0053]

[0054] W1 to W7 in the above table represent the absorption peak positions of the first target gas. At this time, the absorption peak positions of the first target gas are within the absorption peak position range of the first target gas at room temperature.

[0055] Then, a relationship model between the laser operating temperature and the ambient temperature is established by using a linear fitting method with the temperature in the optical cavity as the horizontal coordinate and the laser operating temperature as the vertical coordinate, as the ambient temperature relationship model.

[0056] During the field test, the temperature inside the optical cavity is detected in real time based on the thermistor on the laser gas sensor, and then the ambient temperature relationship model obtained by (3) is used to calculate the laser target operating temperature of the first target gas at the current ambient temperature in real time.

[0057] In another specific embodiment, the ambient temperature relationship model is expressed as y=-(4×10 -6 ) x 2 +0.0406x+1139.4, as attached Figure 3 As shown;

[0058] It should be noted that the attached Figure 3 The temperature T in the optical cavity in the ambient temperature relationship model shown is the temperature AD value collected by the processor in the laser gas sensor. Accordingly, the calculated operating temperature needs to be converted into degrees Celsius.

[0059] Example 3

[0060] The difference between this embodiment and the above embodiment is that when the response value I is less than or equal to the first threshold value V1 and the laser is dynamically adjusted, the following steps are executed:

[0061] As attached Figure 1 As shown, according to the difference in absorption spectra corresponding to the two target gases, the current correction coefficient and the real-time operating current of the laser, the target operating current of the laser is determined, and the laser is dynamically adjusted based on the target operating current of the laser;

[0062] or,

[0063] As attached Figure 2 As shown in the figure, the target operating temperature T of the laser is determined based on the absorption line difference of the two target gases, the temperature correction coefficient and the real-time operating temperature of the laser. 实2 , with the target operating temperature T of the laser 实2 Dynamically adjust the laser for the benchmark.

[0064] It should be noted that there is no first target gas in the optical cavity, and the real-time position P of the absorption peak of the first target gas cannot be obtained. 实 1. Real-time position of absorption peak P 实1It may be close to 0. At this time, it is impossible to calculate the real-time position P of the absorption peak corresponding to the first target gas. 实1 and the relative position difference of the absorption peaks of the two target gases to determine the absorption peak position of the second target gas;

[0065] Therefore, when the first target gas does not exist in the optical cavity, the output wavelength of the laser needs to be dynamically adjusted again to match the output wavelength of the laser with the absorption peak position of the second target gas in order to quickly and accurately detect the concentration of the second target gas.

[0066] In a specific embodiment, as shown in the attached Figure 1 As shown, when the response value I ≤ the first threshold V1, the following steps are specifically performed:

[0067] Determine the target operating current of the laser based on the difference in absorption spectra corresponding to the two target gases, the current correction factor, and the real-time operating current of the laser;

[0068] Among them, the target operating current of the laser = the real-time operating current of the laser ± (the difference in the absorption spectrum lines corresponding to the two target gases × the current correction coefficient). The difference in the absorption spectrum lines corresponding to the two target gases refers to the difference in the absorption peak positions of the two target gases stored in advance. For example, the absorption peak position of methane is 1653.7 nm, and the absorption peak position of ethane is 1654 nm. The difference in the absorption spectrum lines corresponding to methane and ethane is 0.3 nm. The current correction coefficient = 1 / peak wavelength current drift coefficient. For example, if the peak wavelength current drift coefficient is 0.01 nm / mA, the current correction coefficient is 100 mA / nm. The target operating current of the laser = the real-time operating current of the laser + 30 mA.

[0069] Dynamically adjust the output wavelength of the laser based on the target operating current;

[0070] Determine the response value II and the real-time position P of the absorption peak corresponding to the second target gas 实2 , judge whether the response value II is greater than the second threshold value V2, if the response value II> the second threshold value V2, then at the absorption peak real-time position P 实2 When the second target gas is in the preset absorption peak interval, the concentration of the second target gas is obtained using the calibration curve of the second target gas.

[0071] In another specific embodiment, as shown in the attached Figure 2 As shown, when the response value I ≤ the first threshold V1, the following steps are specifically performed:

[0072] The target operating temperature T of the laser is determined based on the difference in the absorption spectra of the two target gases, the temperature correction coefficient, and the real-time operating temperature of the laser. 实2 ;

[0073] Among them, the target operating temperature of the laser is T 实2 = the real-time operating temperature of the laser ± (the difference in the absorption spectra corresponding to the two target gases × the temperature correction coefficient). The difference in the absorption spectra corresponding to the two target gases refers to the difference in the absorption peak positions of the two target gases stored in advance. For example, the absorption peak position of methane is 1653.7 nm, and the absorption peak position of ethane is 1654 nm. The difference in the absorption spectra corresponding to methane and ethane is 0.3 nm. The temperature correction coefficient = 1 / peak wavelength temperature drift coefficient. For example, if the peak wavelength temperature drift coefficient is 0.1 nm / °C, the temperature correction coefficient is 10°C / nm. The target operating temperature T of the laser is 实2 =The real-time operating temperature of the laser + 3°C;

[0074] The target operating temperature T 实2 Dynamically adjust the output wavelength of the laser for the reference;

[0075] Determine the response value II and the real-time position P of the absorption peak corresponding to the second target gas 实2 , judge whether the response value II is greater than the second threshold value V2, if the response value II> the second threshold value V2, then at the absorption peak real-time position P 实2 When the second target gas is in the preset absorption peak interval, the concentration of the second target gas is obtained using the calibration curve of the second target gas.

[0076] Example 4

[0077] The difference between this embodiment and the above embodiment is that:

[0078] As attached Figure 1 and attached Figure 2 As shown, the real-time position P of the absorption peak 实2 When the second target gas is outside the preset absorption peak range, the following steps are also performed:

[0079] Fine-tune the operating temperature of the laser with a preset step size, and re-determine the response value II and the real-time position P of the absorption peak corresponding to the second target gas 实2 , judge whether the new response value II is greater than the second threshold V2, the new absorption peak real-time position P 实2 Whether it is within the preset absorption peak range of the second target gas.

[0080] It should be noted that, in order to improve the accuracy of the detection result of the second target gas concentration, the present invention uses a temperature control device (such as a thermostat or a thermocouple) to monitor and adjust the operating temperature of the laser, and also detects the real-time position P of the absorption peak. 实2Whether it is within the preset absorption peak range of the second target gas; if the real-time position of the absorption peak corresponding to the second target gas is not within the preset absorption peak range, it means that the laser output wavelength, which is dynamically adjusted according to the difference in the absorption spectral lines corresponding to the two target gases, may not be locked within the preset absorption peak range of the second target gas for some reason, and needs to be fine-tuned again until the real-time position of the absorption peak of the second target gas is within the preset absorption peak range.

[0081] It should also be noted that the preset step size is a pre-set step size parameter; generally, the initial preset step size is 5, and the subsequent step sizes may be 3, 2, 1, 0.5, 0.1, etc.;

[0082] When the absorption peak position of the second target gas moves to the right, the operating temperature target value of the laser is reduced by the set step size; when the real-time absorption peak position of the second target gas moves to the left, the operating temperature target value of the laser is increased by the set step size;

[0083] When the above-mentioned fine-tuning steps are repeated, the step size can be dynamically adjusted according to the size of the absorption peak position offset. For example, when the absorption peak position offset decreases, a smaller step size is automatically selected; as the absorption peak of the second target gas gradually approaches the absorption peak position set before leaving the factory, the laser operating temperature is changed with a smaller step size.

[0084] It should also be noted that after using a temperature control device (such as a thermostat or thermocouple) to monitor and adjust the operating temperature of the laser, the real-time position of the absorption peak of the second target gas is also determined. If the real-time position of the absorption peak of the second target gas is within the preset absorption peak range of the second target gas, it means that the detected concentration detection result of the second target gas is accurate.

[0085] Example 5

[0086] The difference between this embodiment and the above embodiment is that:

[0087] As attached Figure 1 and attached Figure 2 As shown, at the real-time position of the absorption peak P 实1 When the target gas is outside the preset absorption peak range, the following steps are also performed:

[0088] Fine-tuning the operating temperature of the laser with a preset step size so that the laser output wavelength is stabilized within a preset absorption peak range of the first target gas;

[0089] And re-determine the response value I and the real-time position P of the absorption peak corresponding to the first target gas 实1 , judge whether the new response value I is greater than the first threshold V1, the new absorption peak real-time position P 实1 Whether it is within the preset absorption peak range of the first target gas.

[0090] It should be noted that, in order to improve the accuracy of the detection result of the first target gas concentration, the present invention uses a temperature control device (such as a thermostat or a thermocouple) to monitor and adjust the operating temperature of the laser, and also detects the real-time position P of the absorption peak. 实1 Whether it is within the preset absorption peak range of the first target gas; if the real-time position of the absorption peak corresponding to the first target gas is not within the preset absorption peak range of the first target gas, it means that the laser output wavelength dynamically adjusted according to the real-time temperature value T may not be locked in the preset absorption peak position of the first target gas for some reason, and needs to be fine-tuned again until the real-time position of the absorption peak of the first target gas is within the preset absorption peak range.

[0091] It should also be noted that the preset step size is a pre-set step size parameter, generally the initial preset step size is 5, and the subsequent step sizes can be 3 or 2 or 1 or 0.5 or 0.1, etc.;

[0092] When the absorption peak position of the first target gas moves to the right, the operating temperature target value of the laser is decreased by the set step size. When the real-time absorption peak position of the first target gas moves to the left, the operating temperature target value of the laser is increased by the set step size. When the above-mentioned fine-tuning steps are repeated, the step size can be dynamically adjusted according to the size of the absorption peak position offset.

[0093] Example 6

[0094] The difference between this embodiment and the above embodiment is that when the concentration of the first target gas is obtained by using the calibration curve of the first target gas, the following steps are performed:

[0095] Obtaining a pre-configured concentration calibration curve I; wherein the concentration calibration curve I includes a plurality of first target gas calibration curves at different optical cavity temperatures, and different optical cavity temperatures correspond to different first target gas calibration curves;

[0096] Reading a real-time temperature value T in an optical cavity of the laser gas sensor, and determining whether a first target gas calibration curve corresponding to the real-time temperature value T is pre-stored in the laser gas sensor;

[0097] If so, the first target gas concentration is calculated directly based on the corresponding first target gas calibration curve and response value I;

[0098] If not, two groups of first target gas characteristic points associated with the real-time temperature value T are screened out, and a new first target gas calibration curve is interpolated using the two screened groups of first target gas characteristic points; the response value I is read, and the real-time concentration of the first target gas is calculated through the response value I and the new first target gas calibration curve.

[0099] In some embodiments, when obtaining the concentration of the second target gas using the calibration curve of the second target gas, the following steps are performed:

[0100] Obtaining a pre-configured concentration calibration curve II; wherein the concentration calibration curve II includes a plurality of second target gas calibration curves at different optical cavity temperatures, and different optical cavity temperatures correspond to different second target gas calibration curves;

[0101] Reading a real-time temperature value T in the optical cavity of the laser gas sensor, and determining whether a second target gas calibration curve corresponding to the real-time temperature value T is pre-stored in the laser gas sensor;

[0102] If so, the second target gas concentration is calculated directly based on the corresponding second target gas calibration curve and response value II;

[0103] If not, two groups of second target gas characteristic points associated with the real-time temperature value T are screened out, and a new second target gas calibration curve is interpolated using the two screened groups of second target gas characteristic points; the response value II is read, and the real-time concentration of the second target gas is calculated through the response value II and the new second target gas calibration curve.

[0104] In a specific embodiment, the laser multi-gas micro-leak detection method is described by taking the first target gas as water vapor and the second target gas as ammonia as an example;

[0105] Before leaving the factory, a calibration environment is set up. The equipment used includes a high and low temperature test chamber (used to change the current ambient temperature of the laser gas sensor), an infrared analyzer (used to monitor the accuracy of gas distribution), and a gas distribution instrument (used to achieve target gas output with different gas concentrations). Water vapor or ammonia of different concentrations is introduced at the same ambient temperature. Then, water vapor or ammonia of different concentrations is introduced again after changing the ambient temperature. The AD values ​​(response values, which refer to the ratio of the second harmonic amplitude to the first harmonic amplitude) of water vapor or ammonia at different ambient temperatures are recorded and stored in the laser gas sensor, as shown in the following table:

[0106] Table 1

[0107]

[0108] Table 2

[0109]

[0110] The temperatures t1 to t4 in the table above are the temperature values ​​inside the optical cavity of the laser gas sensor;

[0111] Fit the water vapor calibration curve and ammonia calibration curve at different optical cavity temperatures (the horizontal axis is the AD value, the vertical axis is the concentration value) and store them in the laser gas sensor;

[0112] During on-site testing, for example, the temperature inside the optical cavity of the laser gas sensor is T0. If an ammonia calibration curve corresponding to T0 is pre-stored, the ammonia concentration is calculated based on the real-time AD value and the corresponding ammonia calibration curve.

[0113] If the ammonia calibration curve corresponding to T0 is not pre-stored, the ammonia characteristic point corresponding to T1 (5ppm, AD 1,1 )、(10ppm,AD 1,2 )…(100ppm, AD 1,5 )) and the ammonia characteristic point corresponding to T2 ((5ppm, AD 2,1 )、(10ppm,AD 2,2 )…(100ppm, AD 2,5 )), then use the ammonia characteristic points corresponding to T1 and T2 (T1>T0, T2<T0) to interpolate a new ammonia calibration curve; the corresponding characteristic points on the new ammonia calibration curve are calculated according to the following formula (T1-T2) / (AD 1,1 -AD 2,1 ) = (T0-T2) / (AD x,1 -AD 2,1 ),…,(T1-T2) / (AD 1,5 -AD 2,5 ) = (T0-T2) / (AD x,5 -AD 2,5 ), and obtain 5 characteristic points (5ppm, response value II x,1 ), (10ppm, response value Ⅱ x,2 )…(100ppm, response value Ⅱ x,5 ), and then fit a new ammonia calibration curve, and then calculate the ammonia concentration based on the real-time AD value and the corresponding ammonia calibration curve;

[0114] It should be noted that the specific steps of obtaining the water vapor concentration using the water vapor calibration curve are similar to the specific steps of obtaining the ammonia concentration using the ammonia calibration curve, and will not be repeated here.

[0115] In another specific embodiment, taking the first target gas as methane and the second target gas as ethane as an example, the specific steps of the laser multi-gas micro-leak detection method are similar to the specific steps in the previous specific embodiment, with the following differences: a calibration environment is set up before leaving the factory, the AD values ​​of methane or ethane at different ambient temperatures are recorded, and the methane calibration curve and the ethane calibration curve at different optical cavity temperatures are fitted and stored in the laser gas sensor;

[0116] During field testing, if a methane calibration curve corresponding to the temperature inside the optical cavity of the laser gas sensor is pre-stored, the methane concentration is calculated based on the real-time AD value and the corresponding methane calibration curve. If a methane calibration curve corresponding to the temperature inside the optical cavity is not pre-stored, a new methane calibration curve is interpolated using two sets of methane characteristic points corresponding to temperatures near the optical cavity temperature, and the methane concentration is then calculated based on the real-time AD value.

[0117] It should be noted that the specific steps of obtaining the ethane concentration using the ethane calibration curve are similar to the above specific steps and will not be repeated here.

[0118] Example 7

[0119] Based on the same inventive concept, an embodiment of the present application provides a laser multi-gas micro-leakage detection system for implementing the above-mentioned laser multi-gas micro-leakage detection method.

[0120] As attached Figure 4 As shown, the laser multi-gas micro-leak detection system includes a processor and a laser drive control circuit, a signal processing circuit, and a temperature sensor connected to the processor. The laser drive control circuit is used to dynamically adjust the operating temperature or operating current of the laser. The temperature sensor is used to detect the real-time temperature value in the optical cavity of the laser gas sensor. The signal processing circuit is used to transmit a response value I corresponding to the first target gas and a response value II corresponding to the second target gas to the processor.

[0121] It also includes a memory for storing computer programs, and the processor is used to implement the laser multi-gas micro-leak detection method as described in Example 1, 2, 3, 4, 5, or 6 when executing the program stored in the memory.

[0122] It should be noted that the solution provided by the laser multi-gas micro-leak detection system is similar to the solution described in the above method. For specific limitations, please refer to the limitations of the laser multi-gas micro-leak detection method above, which will not be repeated here.

[0123] Example 8

[0124] Based on the same inventive concept, an embodiment of the present application provides a readable storage medium for implementing the above-mentioned laser multi-gas micro-leak detection method, on which instructions are stored. When executed by one or more processors, the processors execute the laser multi-gas micro-leak detection method as in 1 or 2 or 3 or 4 or 5 or 6.

[0125] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments. In particular, any reference to memory, database, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may be, but are not limited to, general-purpose processors, central processing units (CPUs), graphics processors (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), data processing logic devices based on quantum computing, and the like.

[0126] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solutions of the present invention. They should all be included in the scope of the technical solutions claimed for protection by the present invention.

Claims

1. A laser multi-gas micro-leak detection method, characterized in that: include: Determine the real-time temperature value T in the optical cavity of the laser gas sensor, and use the real-time temperature value T and the pre-configured ambient temperature relationship model to determine the target operating temperature T of the laser in the laser gas sensor. 实1 ; Wherein, the ambient temperature relationship model refers to the relationship model between the real-time temperature value in the optical cavity and the target operating temperature of the laser; The target operating temperature T 实1 As a benchmark, the laser is dynamically adjusted; Determine the response value I and the real-time position P of the absorption peak corresponding to the first target gas 实1 , judging whether the response value I is greater than a first threshold value V1; If so, determine the real-time position P of the absorption peak 实1 Whether it is in the preset absorption peak range of the first target gas, if it is in the preset absorption peak range of the first target gas, the concentration of the first target gas is obtained by using the calibration curve of the first target gas; based on the real-time position P of the absorption peak corresponding to the first target gas 实1 and the relative position difference of the absorption peaks between the two target gases, determining the absorption peak position of the second target gas to determine the response value II corresponding to the second target gas, and when the response value II corresponding to the second target gas is greater than the second threshold value V2, using the calibration curve of the second target gas to obtain the concentration of the second target gas; If not, the laser is adjusted dynamically, and the response value II and the absorption peak real-time position P corresponding to the second target gas are determined. 实2 , judge whether the response value II is greater than the second threshold value V2, if it is greater than the second threshold value V2, then at the absorption peak real-time position P 实2 When the second target gas is in the preset absorption peak interval, the concentration of the second target gas is obtained using the calibration curve of the second target gas.

2. The laser multi-gas micro-leak detection method according to claim 1, characterized in that: The target operating temperature T of the laser in the laser gas sensor is determined by using the temperature real-time value T and the pre-configured ambient temperature relationship model. 实1 When executing: Obtain a pre-configured ambient temperature relationship model, wherein the ambient temperature relationship model is expressed as y=-ax 2 +bx+c, y represents the target operating temperature that matches a certain temperature real-time value, x represents the real-time temperature value in the optical cavity of the laser gas sensor, a represents the first correction coefficient, b represents the second correction coefficient, and c represents the third correction coefficient; The target operating temperature T that matches the current ambient temperature is determined by using the temperature real-time value T and the ambient temperature relationship model. 实1 .

3. The laser multi-gas micro-leakage detection method according to claim 1 or 2, characterized in that: When the response value I is less than or equal to the first threshold value V1 and the laser is dynamically adjusted, the following steps are executed: According to the difference in the absorption spectra corresponding to the two target gases, the current correction coefficient and the real-time operating current of the laser, the target operating current of the laser is determined, and the laser is dynamically adjusted based on the target operating current of the laser; or, The target operating temperature T of the laser is determined based on the difference in the absorption spectra of the two target gases, the temperature correction coefficient, and the real-time operating temperature of the laser. 实2 , with the target operating temperature T of the laser 实2 Dynamically adjust the laser for the benchmark.

4. The laser multi-gas micro-leak detection method according to claim 3, characterized in that: At the absorption peak real-time position P 实2 When the second target gas is outside the preset absorption peak range, the following steps are also performed: Fine-tune the operating temperature of the laser with a preset step size, and re-determine the response value II and the real-time position P of the absorption peak corresponding to the second target gas 实2 , judge whether the new response value II is greater than the second threshold V2, the new absorption peak real-time position P 实2 Whether it is within the preset absorption peak range of the second target gas.

5. The laser multi-gas micro-leakage detection method according to claim 4, characterized in that: At the real-time position of the absorption peak P 实1 When the target gas is outside the preset absorption peak range, the following steps are also performed: Fine-tune the operating temperature of the laser with a preset step size, and re-determine the response value I and the absorption peak real-time position P corresponding to the first target gas 实1 , judge whether the new response value I is greater than the first threshold V1, the new absorption peak real-time position P 实1 Whether it is within the preset absorption peak range of the first target gas.

6. The laser multi-gas micro-leak detection method according to claim 1, characterized in that: When the response value I is less than or equal to the first threshold V1, further executing: Output a detection result indicating that the concentration of the first target gas is 0.

7. The laser multi-gas micro-leakage detection method according to claim 1, characterized in that: When the response value II is less than or equal to the second threshold value V2, further executing: Output the detection result that the concentration of the second target gas is 0.

8. The laser multi-gas micro-leak detection method according to claim 1, characterized in that: When using the calibration curve of the first target gas to obtain the concentration of the first target gas, execute: Obtaining a pre-configured concentration calibration curve I; wherein the concentration calibration curve I includes a plurality of first target gas calibration curves at different optical cavity temperatures; Reading a real-time temperature value T in an optical cavity of the laser gas sensor, and determining whether a first target gas calibration curve corresponding to the real-time temperature value T is pre-stored in the laser gas sensor; If so, the first target gas concentration is calculated directly based on the corresponding first target gas calibration curve and response value I; If not, two groups of first target gas characteristic points associated with the real-time temperature value T are screened out, and a new first target gas calibration curve is interpolated using the two screened groups of first target gas characteristic points; the response value I is read, and the real-time concentration of the first target gas is calculated through the response value I and the new first target gas calibration curve.

9. A laser multi-gas micro-leakage detection system, characterized in that: The system comprises a processor and a laser drive control circuit, a signal processing circuit and a temperature sensor connected to the processor, and also comprises a memory for storing computer programs. The processor is configured to implement the laser multi-gas micro-leak detection method according to any one of claims 1 to 8 when executing the program stored in the memory.

10. A readable storage medium, characterized in that: Instructions are stored thereon, which, when executed by one or more processors, enable the processors to execute the laser multi-gas micro-leak detection method according to any one of claims 1 to 8.

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