CN118329332A - Laser multi-gas micro-leakage detection method, system and medium - Google Patents
Laser multi-gas micro-leakage detection method, system and medium Download PDFInfo
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- 238000010521 absorption reaction Methods 0.000 claims abstract description 141
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 43
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 40
- 229910021529 ammonia Inorganic materials 0.000 description 21
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
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- 238000000041 tunable diode laser absorption spectroscopy Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
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- MEKDPHXPVMKCON-UHFFFAOYSA-N ethane;methane Chemical compound C.CC MEKDPHXPVMKCON-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention provides a laser multi-gas micro-leakage detection method, a system and a medium, wherein the method comprises the following steps: determining a target working temperature T Real world 1 of a laser in the laser gas sensor by using a temperature real-time value T and a pre-configured environmental temperature relation model, and dynamically adjusting the laser; determining a response value I corresponding to the first target gas and an absorption peak real-time position P Real world 1, and judging whether the response value I is larger than a first threshold value V1 or not; if yes, judging whether the real-time absorption peak position P Real world 1 is in a preset absorption peak interval of the first target gas, and if yes, obtaining the concentration of the first target gas by using a calibration curve of the first target gas; when the response value II corresponding to the second target gas is larger than a second threshold value V2, the concentration of the second target gas is obtained by using a calibration curve of the second target gas; if not, dynamically adjusting the laser, determining a response value II corresponding to the second target gas and an absorption peak real-time position P Real world 2, judging whether the response value II is larger than a second threshold V2, and if so, obtaining the concentration of the second target gas by using a calibration curve of the second target gas when the absorption peak real-time position P Real world 2 is in a preset absorption peak interval.
Description
Technical Field
The invention relates to the technical field of laser gas detection, in particular to a laser multi-gas micro-leakage detection method, a laser multi-gas micro-leakage detection system and a laser multi-gas micro-leakage detection medium.
Background
The laser gas sensor is a device for detecting the concentration of target gas in the environment by utilizing a laser spectrum technology, and when the temperature of the external environment changes, the blue shift or the red shift of the output wavelength of the laser can be caused, so that the accuracy of gas detection is affected. It should be noted that blue shift and red shift are phenomena that describe in physics the shift of the spectrum in the short-wave direction (blue end) or the long-wave direction (red end), which are mainly due to the change in the thermal expansion coefficient of the material inside the laser caused by the temperature change, and the change in the refractive index inside the optical cavity, resulting in a change in the laser wavelength.
It should be noted that, there may be multiple types of target gases in the environment to be measured, and for gas detection, a laser is generally used to determine the concentration of a specific gas by measuring the absorption of the laser light by the specific gas. Each gas has its specific absorption spectrum, i.e. the degree of absorption of laser light of different wavelengths is different; therefore, if the output wavelength of the laser is shifted due to a temperature change, it may no longer accurately correspond to the absorption peak of the target gas, resulting in a decrease in the accuracy of gas detection, and thus, it is necessary to take measures to reduce the influence of the external environmental temperature change on the output wavelength of the laser, especially in a complex environment where it is necessary to measure a plurality of gas concentrations simultaneously.
It should be further noted that, because there may be multiple types of target gases in the environment, it is important to design a detection device capable of measuring multiple types of gases at the same time, which is not only helpful for users to more comprehensively understand environmental conditions, but also provides critical data support for various applications, such as industrial production, environmental monitoring, safety detection, etc.; while prior art multiparameter gas detectors can measure and monitor multiple gas parameters simultaneously, these devices typically contain multiple lasers inside, one laser for each type of target gas; for example, chinese patent application No. cn202321286801.X discloses a methane-ethane detector based on TDLAS principle, which includes a methane laser and an ethane laser disposed on a circuit board, wherein a light beam emitted by the methane laser and a light beam emitted by the ethane laser are coupled by a beam combiner and then enter an optical path cell, so as to measure methane and ethane content simultaneously based on TDLAS principle. Therefore, the existing multi-parameter gas detector generally performs concentration detection on each gas individually, which results in complex structure and high cost of the whole device.
Therefore, it is necessary to design a detecting apparatus which is simple in structure and suitable for measuring a plurality of gas concentrations at the same time.
In order to solve the above problems, an ideal technical solution is always sought.
Disclosure of Invention
In view of the foregoing, it is desirable to provide a laser multi-gas micro-leakage detection method, system and medium.
In order to achieve the above object, a first aspect of the present invention provides a laser multi-gas micro-leakage detection method, comprising: determining a temperature real-time value T in an optical cavity in the laser gas sensor, and determining a target working temperature T Real world 1 of a laser in the laser gas sensor by using the temperature real-time value T and a pre-configured environmental temperature relation model; the environment temperature relation model refers to a relation model between a real-time temperature value in the optical cavity and a target working temperature of the laser;
Dynamically adjusting the laser by taking the target working temperature T Real world 1 as a reference; determining a response value I corresponding to the first target gas and an absorption peak real-time position P Real world 1, and judging whether the response value I is larger than a first threshold value V1 or not;
If so, judging whether the real-time absorption peak position P Real world 1 is in a preset absorption peak interval of the first target gas, and if so, obtaining the concentration of the first target gas by using a calibration curve of the first target gas; determining the absorption peak position of the second target gas based on the real-time absorption peak position P Real world 1 corresponding to the first target gas and the relative absorption peak position difference between the two target gases so as to determine a response value II corresponding to the second target gas, and when the response value II corresponding to the second target gas is greater than a second threshold value V2, obtaining the concentration of the second target gas by using a calibration curve of the second target gas;
if not, dynamically adjusting the laser, determining a response value II corresponding to the second target gas and an absorption peak real-time position P Real world 2, judging whether the response value II is larger than a second threshold V2, and if so, obtaining the concentration of the second target gas by using a calibration curve of the second target gas when the absorption peak real-time position P Real world 2 is in a preset absorption peak interval of the second target gas.
In order to achieve the above object, a second aspect of the present invention provides a laser multi-gas micro-leakage detection system, which includes a processor, a laser driving control circuit, a signal processing circuit and a temperature sensor connected to the processor, and a memory for storing a computer program, where the processor is configured to implement the above-mentioned laser multi-gas micro-leakage detection method when executing the program stored on the memory.
In order to achieve the above object, a third aspect of the present invention provides a readable storage medium having stored thereon instructions, which when executed by one or more processors, cause the processors to perform a laser multi-gas micro-leak detection method as described above.
The beneficial effects of the invention are as follows:
The invention adopts a preconfigured environmental temperature relation model to dynamically adjust the working temperature of the laser, and then selects and adopts different strategies to dynamically adjust the output wavelength of the laser according to whether the first target gas exists in the optical cavity of the laser gas sensor, so that the output wavelength of the laser is matched with the environment to be measured; whether the first target gas exists in the environment to be detected or not, the concentration of the target gas can be rapidly and accurately detected dynamically.
Drawings
FIG. 1 is a schematic flow chart of a laser multi-gas micro-leakage detection method according to the present invention;
FIG. 2 is a flow chart of a laser multi-gas micro-leakage detection method according to the present invention;
FIG. 3 is a schematic diagram of an ambient temperature relationship model in one embodiment;
Fig. 4 is a schematic block diagram of a laser multi-gas micro-leak detection system of the present invention.
Detailed Description
The technical scheme of the invention is further described in detail through the following specific embodiments.
For convenience of understanding, the interactive party and/or the term and/or the custom word related in the present invention are described first in connection with the technical scheme of the present invention:
Laser gas sensor: the invention relates to a sensor for detecting the concentration of target gas in the environment by utilizing a laser spectrum technology, which mainly comprises a laser, an optical cavity, a photoelectric detector, a signal processing circuit for processing and analyzing the electric signal output by the photoelectric detector, and the like; target gases include, but are not limited to, steam and ammonia, methane and ethane, and the like.
Temperature real-time value T: refers to the real-time value of the temperature in the optical cavity of the laser gas sensor, which is related to the external environment where the laser gas sensor is currently located.
Ambient temperature relationship model: refers to a model of the relationship between the real-time value of the temperature within the optical cavity and the target operating temperature of the laser, which is preconfigured and pre-stored in the laser gas sensor;
Target operating temperature of the laser, T Real world 1: refers to an operating temperature that matches a 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 typically used to monitor and adjust the operating temperature of the laser.
Response value: the AD value corresponding to the first target gas is a response value I, and the AD value corresponding to the second target gas is a response value II;
First threshold V1: the method comprises the steps of referring to a preset threshold value of an AD value corresponding to a first target gas, if a response value I is larger than a first threshold value V1, indicating that the first target gas exists in an optical cavity of the laser gas sensor, and if the response value I is smaller than or equal to the first threshold value V1, indicating that the first target gas does not exist in the optical cavity of the laser gas sensor;
Second threshold V2: the threshold value of the AD value corresponding to the second target gas is preset, if the response value II is larger than the second threshold value V2, the second target gas exists in the optical cavity of the laser gas sensor, and if the response value II is smaller than or equal to the second threshold value V2, the second target gas does not exist in the optical cavity of the laser gas sensor.
Preset absorption peak interval of the first target gas: refers to a preconfigured range of standard or theoretical absorption peak positions of the first target gas, for example, a preset absorption peak interval of water vapor is 1512.2 nm-1512.8 nm, and a preset absorption peak interval of methane is 1653.6-1653.8 nm;
preset absorption peak interval of the second target gas: refers to a preconfigured range of standard or theoretical absorption peak positions of the second target gas, for example, the preset absorption peak interval of ammonia is 1512.0 nm to 1512.4 nm, and the preset absorption peak interval of ethane is 1653.9nm to 1654.1nm.
In the laser gas sensor, the absorption peak position of the gas refers to the peak position shown by the absorption characteristic of the gas molecule to the laser with a specific wavelength, and different gas molecules have different absorption peak positions, so that the relative position difference of the absorption peaks between two target gases can be prestored in the laser gas sensor; the laser gas sensor may generally determine the position of the absorption peak by using a lock-in amplification technique, and the specific manner is not described herein.
It should be further noted that, the real-time position of the absorption peak may change in real time with time or other external conditions (including environmental conditions, gas concentration, temperature, pressure, and stability of the laser source itself); therefore, the absorption peak real-time position P Real world 1 corresponding to the first target gas and the absorption peak real-time position P Real world 2 corresponding to the second target gas in the present invention each refer to an absorption peak position after a change with time or other external conditions.
Example 1
As shown in fig. 1 and fig. 2, the present embodiment provides a specific implementation manner of a laser multi-gas micro-leakage detection method, where the laser multi-gas micro-leakage detection method includes:
determining a temperature real-time value T in an optical cavity in the laser gas sensor, and determining a target working temperature T Real world 1 of a laser in the laser gas sensor by using the temperature real-time value T and a pre-configured environmental temperature relation model; the environment temperature relation model refers to a relation model between a real-time temperature value in the optical cavity and a target working temperature of the laser;
Dynamically adjusting the laser by taking the target working temperature T Real world 1 as a reference;
Determining a response value I corresponding to the first target gas and an absorption peak real-time position P Real world 1, and judging whether the response value I is larger than a first threshold value V1 or not;
If so, judging whether the absorption peak real-time position P Real world 1 is in a preset absorption peak interval of the first target gas, and if the absorption peak real-time position P Real world 1 is in the preset absorption peak interval of the first target gas, obtaining the concentration of the first target gas by using a calibration curve of the first target gas; determining the absorption peak position of the second target gas based on the real-time absorption peak position P Real world 1 corresponding to the first target gas and the pre-stored relative absorption peak position difference between the two target gases so as to determine a response value II corresponding to the second target gas, and when the response value II corresponding to the second target gas is greater than a second threshold value V2, obtaining the concentration of the second target gas by using a calibration curve of the second target gas;
if not, dynamically adjusting the laser, determining a response value II corresponding to the second target gas and an absorption peak real-time position P Real world 2, judging whether the response value II is larger than a second threshold V2, and if so, obtaining the concentration of the second target gas by using a calibration curve of the second target gas when the absorption peak real-time position P Real world 2 is in a preset absorption peak interval of the second target gas.
In some embodiments, when the response value i is less than or equal to the first threshold V1, further performing: and outputting a detection result that the concentration of the first target gas is 0.
In some embodiments, when the response value ii is less than or equal to the second threshold V2, further performing: and outputting a detection result that the concentration of the second target gas is 0.
It should be noted that when multiple types of target gases exist in the environment to be detected at the same time, the embodiment adopts the pre-configured environmental temperature relation model to dynamically adjust the working temperature of the laser, then detects whether the first target gas exists in the optical cavity according to the comparison result of the response value I and the first threshold value V1, and then detects the concentrations of the two types of target gases by adopting different strategies, so that the concentration of the target gas can be detected rapidly and accurately no matter whether the first target gas exists in the environment to be detected.
When the response value i is less than or equal to the first threshold value V1, it is indicated that the first target gas is not present in the optical cavity, and at this time, the laser needs to be dynamically adjusted again to detect whether the second target gas is present in the optical cavity.
Example 2
This embodiment differs from embodiment 1 in that: when determining the target working temperature T Real world 1 of the laser in the laser gas sensor by using the temperature real-time value T and a pre-configured environmental temperature relation model, executing the following steps:
Obtaining a preconfigured environmental temperature relation model, wherein the environmental temperature relation model is expressed as y= -ax 2 +bx+c, y represents a target working temperature matched with a certain real-time temperature value, x represents the real-time temperature value in an optical cavity in a laser gas sensor, a represents a first correction coefficient, b represents a second correction coefficient, and c represents a third correction coefficient;
And determining a target working temperature T Real world 1 matched with the current environment temperature by using the temperature real-time value T and the environment temperature relation model.
When the external environment temperature changes, the output wavelength of the laser is shifted; in order to solve the problem, when the laser is dynamically adjusted by adopting a preconfigured environmental temperature relation model, the embodiment determines a real-time temperature value T in an optical cavity in the laser gas sensor, determines a target working temperature T Real world 1 of the laser according to the real-time temperature value T and the environmental temperature relation model, dynamically adjusts the laser to ensure that the output wavelength of the laser is near a preset absorption peak position of the first target gas, and then detects the first target gas.
In one embodiment, when the environmental temperature relationship model is configured, the following steps are adopted:
(1) Before leaving the factory, a relation test system between the absorption peak position of the first target gas and a temperature real-time value T in the optical cavity is built, and used equipment comprises a high-low temperature test box (used for changing the current environment temperature of a laser gas sensor), a spectrometer, the first target gas standard gas, a collection card and upper computer software, wherein the collection card and the upper computer software are used for collecting data and the absorption peak position of the first target gas by using a lock-in amplification algorithm Jie Diaochu;
(2) Firstly, setting the absorption peak position of a first target gas at normal temperature, changing the temperature of a high-low temperature test box (for example, heating from-40 ℃ to 70 ℃ at intervals of 10 ℃), introducing the first target gas standard gas with the same concentration after each temperature is stabilized for half an hour, and enabling the absorption peak position of the first target gas to be near the absorption peak position of the first target gas at normal temperature by changing the working temperature of a laser;
(3) Recording the working 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 near the absorption peak position of the first target gas at normal temperature at different temperatures in the optical cavity, as shown in the following table:
W 1 to W 7 in the above table represent absorption peak positions of the first target gas at which the absorption peak positions of the first target gas are within the absorption peak position interval range of the first target gas at normal temperature.
And then establishing a relation model of the working temperature of the laser and the environmental temperature by using a linear fitting method and taking the temperature in the optical cavity as an abscissa and the working temperature of the laser as an ordinate, and taking the relation model as the environmental temperature relation model.
And (3) during field test, detecting the temperature in the optical cavity in real time according to a thermistor on the laser gas sensor, and then calculating the laser target working temperature of the first target gas at the current environment temperature in real time by using the environment temperature relation model obtained in the step (3).
In another embodiment, the ambient temperature relationship model is expressed as y= - (4× -6) x2 +0.0406x+1139.4, as shown in fig. 3;
It should be noted that, the temperature T in the optical cavity in the environmental temperature relationship model shown in fig. 3 is a temperature AD value collected by the processor in the laser gas sensor, and the calculated working temperature needs to be converted into the temperature after conversion.
Example 3
The difference between this embodiment and the above embodiment is that: when the response value I is smaller than or equal to a first threshold value V1 and the laser is dynamically adjusted, executing the following steps:
as shown in fig. 1, determining a target working current of a laser according to an absorption spectrum line difference value, a current correction coefficient and a real-time working current of the laser corresponding to two target gases, and dynamically adjusting the laser by taking the target working current of the laser as a reference;
Or alternatively
As shown in fig. 2, the target working temperature T Real world 2 of the laser is determined according to the absorption line difference value, the temperature correction coefficient and the real-time working temperature of the laser corresponding to the two target gases, and the laser is dynamically adjusted with the target working temperature T Real world 2 of the laser as a reference.
It should be noted that, the first target gas does not exist in the optical cavity, the real-time absorption peak position P Real world of the first target gas cannot be obtained, the real-time absorption peak position P Real world 1 may be close to 0, and at this time, the absorption peak position of the second target gas cannot be determined based on the real-time absorption peak position P Real world 1 corresponding to the first target gas and the relative absorption peak position difference between the two target gases;
Therefore, in the case that the first target gas is not present in the optical cavity, the output wavelength of the laser needs to be dynamically adjusted again so that the output wavelength of the laser matches the absorption peak position of the second target gas, so as to rapidly and accurately detect the concentration of the second target gas.
In one embodiment, as shown in fig. 1, when the response value i is less than or equal to the first threshold value V1, the following steps are specifically performed:
determining the target working current of the laser according to the absorption spectrum line difference value, the current correction coefficient and the real-time working current of the laser corresponding to the two target gases;
wherein, the target working current of the laser=real-time working current of the laser ± (absorption line difference value corresponding to two target gases×current correction coefficient), the absorption line difference value corresponding to two target gases refers to the absorption peak position difference value of two target gases stored in advance, for example, the absorption peak position of methane is 1653.7 nm, the absorption peak position of ethane is 1654 nm, and the absorption line difference value corresponding to methane and ethane is 0.3nm; the current correction coefficient=1/peak wavelength current drift coefficient, if the peak wavelength current drift coefficient is 0.01nm/mA, the current correction coefficient is 100 mA/nm, and the target working current of the laser=the real-time working current of the laser +30 mA;
dynamically adjusting the output wavelength of the laser by taking the target working current as a reference;
And determining a response value II and an absorption peak real-time position P Real world 2 corresponding to the second target gas, judging whether the response value II is larger than a second threshold value V2, and if the response value II is larger than the second threshold value V2, when the absorption peak real-time position P Real world 2 is in a preset absorption peak interval of the second target gas, obtaining the concentration of the second target gas by using a calibration curve of the second target gas.
In another embodiment, as shown in fig. 2, when the response value i is less than or equal to the first threshold value V1, the following steps are specifically performed:
Determining a target working temperature T Real world 2 of the laser according to the difference value of the absorption spectrum lines corresponding to the two target gases, the temperature correction coefficient and the real-time working temperature of the laser;
The target working temperature T Real world 2 of the laser=real-time working temperature of the laser ± (absorption line difference value corresponding to two target gases×temperature correction coefficient), the absorption line difference value corresponding to two target gases refers to the absorption peak position difference value of two target gases stored in advance, for example, the absorption peak position of methane is 1653.7 nm, the absorption peak position of ethane is 1654 nm, and the absorption line difference value corresponding to methane and ethane is 0.3nm; the temperature correction coefficient=1/peak wavelength temperature drift coefficient, if the peak wavelength temperature drift coefficient is 0.1 nm/DEG C, the temperature correction coefficient is 10 ℃/nm, the target working temperature T Real world 2 of the laser=the real-time working temperature +3 ℃ of the laser;
Dynamically adjusting the output wavelength of the laser by taking the target working temperature T Real world 2 as a reference;
And determining a response value II and an absorption peak real-time position P Real world 2 corresponding to the second target gas, judging whether the response value II is larger than a second threshold value V2, and if the response value II is larger than the second threshold value V2, when the absorption peak real-time position P Real world 2 is in a preset absorption peak interval of the second target gas, obtaining the concentration of the second target gas by using a calibration curve of the second target gas.
Example 4
The difference between this embodiment and the above embodiment is that:
As shown in fig. 1 and fig. 2, when the absorption peak real-time position P Real world 2 is outside the preset absorption peak interval of the second target gas, further performing:
And fine-tuning the working temperature of the laser with a preset step length, determining a response value II and an absorption peak real-time position P Real world 2 corresponding to the second target gas again, and judging whether the new response value II is larger than a second threshold value V2 or not and whether the new absorption peak real-time position P Real world 2 is in a preset absorption peak interval of the second target gas or not.
It should be noted that, in order to improve the accuracy of the second target gas concentration detection result, after the working temperature of the laser is monitored and adjusted by using the temperature control device (such as a thermostat or a thermocouple), whether the real-time absorption peak position P Real world 2 is within the preset absorption peak interval of the second target gas is also detected; if the real-time position of the absorption peak corresponding to the second target gas is not in the preset absorption peak interval, the output wavelength of the laser after dynamic adjustment according to the difference value of the absorption spectrum lines corresponding to the two target gases is indicated, and may be unlocked in the preset absorption peak interval of the second target gas for some reasons, and fine adjustment is needed again until the real-time position of the absorption peak of the second target gas is in the preset absorption peak interval.
The preset step length is a preset step length parameter; typically, the initial preset step length is 5, and the subsequent step length can be 3 or 2 or 1 or 0.5 or 0.1, etc.;
When the absorption peak position of the second target gas moves right, the working temperature target value of the laser is reduced by a set step length, and when the real-time absorption peak position of the second target gas moves left, the working temperature target value of the laser is enlarged by the set step length;
When the fine tuning step is repeatedly executed, the step length can be dynamically adjusted according to the position deviation of the absorption peak, and if the position deviation of the absorption peak is reduced, a smaller step length is automatically selected; when the second target gas absorption peak gradually approaches the absorption peak position set before delivery, the working temperature of the laser is changed in a smaller step size.
It should be further noted that, after the working temperature of the laser is monitored and adjusted by using a temperature control device (such as a thermostat or a thermocouple), the real-time position of the absorption peak of the second target gas is also determined, and if the real-time position of the absorption peak of the second target gas is within the preset absorption peak interval of the second target gas, it is indicated that the detected concentration detection result of the second target gas is accurate.
Example 5
The difference between this embodiment and the above embodiment is that:
as shown in fig. 1 and fig. 2, when the absorption peak real-time position P Real world 1 is outside the preset absorption peak interval of the first target gas, further performing:
Trimming the working temperature of the laser with a preset step length so as to ensure that the output wavelength of the laser is stabilized in a preset absorption peak interval of the first target gas;
And determining a response value I and an absorption peak real-time position P Real world 1 corresponding to the first target gas again, and judging whether the new response value I is larger than a first threshold value V1 and whether the new absorption peak real-time position P Real world 1 is in a preset absorption peak interval of the first target gas.
It should be noted that, in order to improve the accuracy of the detection result of the concentration of the first target gas, after the working temperature of the laser is monitored and adjusted by using the temperature control device (such as a thermostat or a thermocouple), whether the real-time position P Real world 1 of the absorption peak is within the preset absorption peak interval of the first target gas is also detected; if the real-time position of the absorption peak corresponding to the first target gas is not within the preset absorption peak interval of the first target gas, it is indicated that the output wavelength of the laser after being dynamically adjusted according to the temperature real-time value T may be unlocked at the preset absorption peak position of the first target gas for some reasons, and fine adjustment is needed again until the real-time position of the absorption peak of the first target gas is within the preset absorption peak interval.
It should be further noted that, the preset step length is a preset step length parameter, generally, the initial preset step length is 5, and the subsequent step length may be 3 or 2 or 1 or 0.5 or 0.1, etc.;
When the absorption peak position of the first target gas moves right, the working temperature target value of the laser is reduced by a set step length, and when the real-time absorption peak position of the first target gas moves left, the working temperature target value of the laser is enlarged by the set step length; and when the fine tuning step is repeatedly executed, the step length can be dynamically adjusted according to the position deviation of the absorption peak.
Example 6
The difference between this embodiment and the above embodiment is that: when the concentration of the first target gas is obtained using the calibration curve of the first target gas, performing:
obtaining a pre-configured concentration calibration curve I; the concentration calibration curve I comprises a plurality of first target gas calibration curves under different optical cavity temperatures, and the different optical cavity temperatures correspond to the different first target gas calibration curves;
reading a temperature real-time value T in an optical cavity in a laser gas sensor, and judging whether a first target gas calibration curve corresponding to the temperature real-time value T is pre-stored in the laser gas sensor or not;
if so, directly calculating the concentration of the first target gas based on the corresponding first target gas calibration curve and the response value I;
If not, screening two groups of first target gas characteristic points associated with the temperature real-time value T, and interpolating a new first target gas calibration curve by using the screened two groups of first target gas characteristic points; and reading a response value I, and calculating the real-time concentration of the first target gas through the response value I and a new first target gas calibration curve.
In some embodiments, using the calibration curve of the second target gas, when obtaining the concentration of the second target gas, performing:
Acquiring a pre-configured concentration calibration curve II; the concentration calibration curve II comprises a plurality of second target gas calibration curves under different optical cavity temperatures, and the different optical cavity temperatures correspond to different second target gas calibration curves;
Reading a temperature real-time value T in an optical cavity in the laser gas sensor, and judging whether a second target gas calibration curve corresponding to the temperature real-time value T is pre-stored in the laser gas sensor or not;
if so, directly calculating the concentration of the second target gas based on the corresponding second target gas calibration curve and the response value II;
If not, screening two groups of second target gas characteristic points associated with the temperature real-time value T, and interpolating a new second target gas calibration curve by using the screened two groups of second target gas characteristic points; and reading a response value II, and calculating the real-time concentration of the second target gas through the response value II and a new second target gas calibration curve.
In a specific embodiment, taking the first target gas as water vapor and the second target gas as ammonia gas as an example, the laser multi-gas micro-leakage detection method is described;
Setting up a calibration environment before leaving a factory, wherein the used equipment comprises a high-low temperature test box (used for changing the current environment temperature of a laser gas sensor), an infrared analyzer (used for monitoring the accuracy of gas distribution) and a gas distribution instrument (used for realizing the output of target gases with different gas concentrations); and (3) introducing water vapor or ammonia with different concentrations under the same environment temperature, then changing the environment temperature, introducing the water vapor or ammonia with different concentrations again, recording AD values (response values refer to the ratio of the second harmonic amplitude to the first harmonic amplitude) of the water vapor or ammonia with different environment temperatures, and storing the AD values to a laser gas sensor, wherein the AD values are shown in the following table:
TABLE 1
TABLE 2
The temperatures t1 to t4 in the table are the temperature values in the optical cavity of the laser gas sensor;
Fitting a water vapor calibration curve and an ammonia calibration curve (the abscissa is an AD value and the ordinate is a concentration value) under different optical cavity temperatures, and storing the water vapor calibration curve and the ammonia calibration curve into a laser gas sensor;
when in field test, if the temperature in 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;
if the ammonia calibration curve corresponding to T0 is not pre-stored, the ammonia characteristic points ((5 ppm, AD 1,1）、（10ppm,AD1,2）…（100ppm,AD1,5)) corresponding to T1 and the ammonia characteristic points ((5 ppm, AD 2,1）、（10ppm,AD2,2）…（100ppm,AD2,5)) corresponding to T2 are pre-stored, and a new ammonia calibration curve is interpolated by utilizing the ammonia characteristic points (T1 is more than T0 and T2 is less than T0) corresponding to T1 and T2; corresponding characteristic points on the new ammonia calibration curve are obtained according to the following formula （T1－T2）/（AD1,1－AD2,1）=（T0－T2）/（ADx,1－AD2,1）、…、（T1－T2）/（AD1,5－AD2,5）=（T0－T2）/（ADx,5－AD2,5）,, 5 characteristic points (5 ppm, response value II x,1), (10 ppm, response value II x,2) … (100 ppm, response value II x,5) are obtained, a new ammonia calibration curve is fitted, and then the ammonia concentration is calculated based on the real-time AD value and the corresponding ammonia calibration curve;
it should be noted that, the specific step of obtaining the water vapor concentration by using the water vapor calibration curve is similar to the specific step of obtaining the ammonia concentration by using the ammonia calibration curve, and will not be described herein.
In another 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-leakage detection method are similar to those in the previous embodiment, except that: setting up a calibration environment before leaving a factory, recording AD values of methane or ethane at different environment temperatures, fitting a methane calibration curve and an ethane calibration curve at different optical cavity temperatures, and storing the methane calibration curve and the ethane calibration curve into a laser gas sensor;
When in field test, if a methane calibration curve corresponding to the temperature in an optical cavity of the laser gas sensor is prestored, calculating the methane concentration based on the real-time AD value and the corresponding methane calibration curve; if the methane calibration curve corresponding to the temperature in the optical cavity is not pre-stored, a new methane calibration curve is interpolated by utilizing two groups of methane characteristic points corresponding to the temperature near the temperature of the optical cavity, and then the methane concentration is calculated based on the real-time AD value;
it should be noted that, the specific steps for obtaining the ethane concentration by using the ethane calibration curve are similar to the specific steps described above, and will not be described herein.
Example 7
Based on the same inventive concept, the embodiment of the application provides a laser multi-gas micro-leakage detection system for realizing the above-mentioned laser multi-gas micro-leakage detection method.
As shown in fig. 4, the laser multi-gas micro-leakage detection system comprises a processor, a laser driving control circuit, a signal processing circuit and a temperature sensor, wherein the laser driving control circuit, the signal processing circuit and the temperature sensor are connected with the processor, the laser driving control circuit is used for dynamically adjusting the working temperature or the working current of a laser, the temperature sensor is used for detecting a real-time temperature value in an optical cavity in the laser gas sensor, and the signal processing circuit is used for transmitting a response value I corresponding to a first target gas and a response value II corresponding to a second target gas to the processor;
The laser multi-gas micro-leakage detection method in the embodiment 1 or2 or 3 or 4 or 5 or 6 is realized when the processor is used for executing the program stored on the memory.
It should be noted that, the implementation scheme of the solution provided by the laser multi-gas micro-leakage detection system is similar to the implementation scheme described in the above method, and specific limitation may be referred to the above limitation of the laser multi-gas micro-leakage detection method, which is not repeated here.
Example 8
Based on the same inventive concept, embodiments of the present application provide a readable storage medium for implementing the laser multi-gas micro-leakage detection method referred to above, having instructions stored thereon, which when executed by one or more processors, cause the processors to perform the laser multi-gas micro-leakage detection method as in 1 or 2 or 3 or 4 or 5 or 6.
Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, database, or other medium used in embodiments provided herein may include at least one of non-volatile and volatile memory. The nonvolatile Memory may include Read-only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical Memory, high density embedded nonvolatile Memory, resistive random access Memory (ReRAM), magneto-resistive random access Memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric Memory (Ferroelectric Random Access Memory, FRAM), phase change Memory (PHASE CHANGE Memory, PCM), graphene Memory, and the like. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, and the like. By way of illustration, and not limitation, RAM can be in various forms such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (DynamicRandomAccess Memory, DRAM), etc. The databases referred to in the embodiments provided herein may include at least one of a relational database and a non-relational database. The non-relational database may include, but is not limited to, a blockchain-based distributed database, and the like. The processor referred to in the embodiments provided in the present application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, or the like, but is not limited thereto.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same; while the invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that: modifications may be made to the specific embodiments of the present invention or equivalents may be substituted for part of the technical features thereof; without departing from the spirit of the invention, it is intended to cover the scope of the invention as claimed.
Claims (10)
1. A method for laser multi-gas micro-leakage detection, comprising:
determining a temperature real-time value T in an optical cavity in the laser gas sensor, and determining a target working temperature T Real world 1 of a laser in the laser gas sensor by using the temperature real-time value T and a pre-configured environmental temperature relation model; the environment temperature relation model refers to a relation model between a real-time temperature value in the optical cavity and a target working temperature of the laser;
Dynamically adjusting the laser by taking the target working temperature T Real world 1 as a reference;
Determining a response value I corresponding to the first target gas and an absorption peak real-time position P Real world 1, and judging whether the response value I is larger than a first threshold value V1 or not;
If so, judging whether the real-time absorption peak position P Real world 1 is in a preset absorption peak interval of the first target gas, and if so, obtaining the concentration of the first target gas by using a calibration curve of the first target gas; determining the absorption peak position of the second target gas based on the real-time absorption peak position P Real world 1 corresponding to the first target gas and the relative absorption peak position difference between the two target gases so as to determine a response value II corresponding to the second target gas, and when the response value II corresponding to the second target gas is greater than a second threshold value V2, obtaining the concentration of the second target gas by using a calibration curve of the second target gas;
if not, dynamically adjusting the laser, determining a response value II corresponding to the second target gas and an absorption peak real-time position P Real world 2, judging whether the response value II is larger than a second threshold V2, and if so, obtaining the concentration of the second target gas by using a calibration curve of the second target gas when the absorption peak real-time position P Real world 2 is in a preset absorption peak interval of the second target gas.
2. The method for detecting laser multi-gas micro-leakage according to claim 1, wherein when determining the target operating temperature T Real world 1 of the laser in the laser gas sensor by using the temperature real-time value T and a pre-configured environmental temperature relation model, performing:
Obtaining a preconfigured environmental temperature relation model, wherein the environmental temperature relation model is expressed as y= -ax 2 +bx+c, y represents a target working temperature matched with a certain real-time temperature value, x represents the real-time temperature value in an optical cavity in a laser gas sensor, a represents a first correction coefficient, b represents a second correction coefficient, and c represents a third correction coefficient;
And determining a target working temperature T Real world 1 matched with the current environment temperature by using the temperature real-time value T and the environment temperature relation model.
3. The method for detecting laser multi-gas micro-leakage according to claim 1 or 2, wherein when the response value i is equal to or smaller than a first threshold V1, dynamically adjusting the laser is performed by:
determining target working current of the laser according to the absorption spectrum line difference value, the current correction coefficient and the real-time working current of the laser corresponding to the two target gases, and dynamically adjusting the laser by taking the target working current of the laser as a reference;
Or alternatively
And determining a target working temperature T Real world 2 of the laser according to the absorption spectrum line difference value, the temperature correction coefficient and the real-time working temperature of the laser corresponding to the two target gases, and dynamically adjusting the laser by taking the target working temperature T Real world 2 of the laser as a reference.
4. The laser multi-gas micro-leakage detection method according to claim 3, wherein when the absorption peak real-time position P Real world 2 is outside a preset absorption peak interval of the second target gas, further performing:
And fine-tuning the working temperature of the laser with a preset step length, determining a response value II and an absorption peak real-time position P Real world 2 corresponding to the second target gas again, and judging whether the new response value II is larger than a second threshold value V2 or not and whether the new absorption peak real-time position P Real world 2 is in a preset absorption peak interval of the second target gas or not.
5. The method according to claim 4, further comprising, when the absorption peak real-time position P Real world 1 is outside a preset absorption peak interval of the first target gas:
And fine-tuning the working temperature of the laser with a preset step length, determining a response value I corresponding to the first target gas and an absorption peak real-time position P Real world 1 again, and judging whether the new response value I is larger than a first threshold value V1 or not and whether the new absorption peak real-time position P Real world 1 is in a preset absorption peak interval of the first target gas or not.
6. The laser multi-gas micro-leak detection method according to claim 1, wherein when the response value i is equal to or smaller than the first threshold value V1, further performing:
and outputting a detection result that the concentration of the first target gas is 0.
7. The laser multi-gas micro-leak detection method according to claim 1, wherein when the response value ii is equal to or smaller than the second threshold value V2, further performing:
And outputting a detection result that the concentration of the second target gas is 0.
8. The method for detecting the micro leakage of the laser light multiple gases according to claim 1, wherein when the concentration of the first target gas is obtained by using the calibration curve of the first target gas, performing:
obtaining a pre-configured concentration calibration curve I; the concentration calibration curve I comprises a plurality of first target gas calibration curves under different optical cavity temperatures;
reading a temperature real-time value T in an optical cavity in a laser gas sensor, and judging whether a first target gas calibration curve corresponding to the temperature real-time value T is pre-stored in the laser gas sensor or not;
if so, directly calculating the concentration of the first target gas based on the corresponding first target gas calibration curve and the response value I;
If not, screening two groups of first target gas characteristic points associated with the temperature real-time value T, and interpolating a new first target gas calibration curve by using the screened two groups of first target gas characteristic points; and reading a response value I, and calculating the real-time concentration of the first target gas through the response value I and a new first target gas calibration curve.
9. A laser multi-gas micro-leakage detection system, comprising a processor, a laser driving control circuit, a signal processing circuit and a temperature sensor which are connected with the processor, and a memory for storing a computer program, wherein the processor is used for realizing the laser multi-gas micro-leakage detection method according to any one of claims 1 to 8 when executing the program stored on the memory.
10. A readable storage medium, characterized by: stored thereon instructions which, when executed by one or more processors, cause the processors to perform the laser multi-gas micro-leak detection method of any of claims 1 to 8.
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| Publication Number | Publication Date |
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| CN118329332A true CN118329332A (en) | 2024-07-12 |
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