Photoacoustic spectrometry gas measuring instrument with self-calibration function

Abstract

The invention discloses a photoacoustic spectrometry gas measuring instrument with a self-calibration function, and relates to the technical field of gas measurement, the photoacoustic spectrometry gas measuring instrument with the self-calibration function comprises a bearing plate, the bearing plate is provided with a laser, a photoacoustic cell, a multi-gas splitter and a sub-calibration gas cell, a first air pump and a second air pump are installed on the two sides of the multi-air branching device respectively, the multi-air branching device is connected with the sub-standard air pool through a plurality of air pipes, a lens is installed between the laser device and the photoacoustic pool, and when calibration is conducted, the first air pump and the fourth electromagnetic valve are started, the second air pump and the first electromagnetic valve are closed, calibration buffering is completed, and the multi-air branching device is connected with the sub-standard air pool through a plurality of air pipes. A first solenoid valve, a second solenoid valve, a third solenoid valve and a second air pump are opened to form an internal closed loop, then a laser is opened, a pressure-sensitive microphone is used for signal difference to obtain photoacoustic signals, photoacoustic signal coefficients in a model are corrected successively by using known gas concentration and recorded in a measurement system, and single calibration is completed.

Description

Technical Field

[0001] This invention relates to the field of gas measurement technology, specifically a photoacoustic spectrometer with self-calibration function. Background Technology

[0002] With increasing public concern about environmental conditions, the demand for photoelectric monitoring of atmospheric environments is becoming increasingly important. Photoacoustic spectrometers are widely used in urban environmental monitoring departments, especially environmental protection departments, for measurements such as those taken along urban roads or in key areas. Additionally, photoacoustic spectrometers can be used in military departments to measure intelligent environmental characteristic parameters, complete the construction of terrestrial environmental characteristic data, and provide technical and data support for optoelectronic weapons and optoelectronic detection systems. They can also be applied in intelligent research departments and in the measurement of special gases (toxic gases, battlefield smoke), among other related fields. However, the calibration of current photoacoustic spectrometers is complex. On the one hand, it requires professionals with extensive experience and expertise to operate strictly according to cumbersome procedures, which not only consumes a lot of manpower and time but also makes it difficult to guarantee the consistency and accuracy of each calibration. On the other hand, the calibration process often requires multiple high-precision standard samples and professional calibration equipment, which are expensive and require regular calibration and maintenance, further increasing the barrier to entry and operating costs. Furthermore, because the equipment is quite sensitive to environmental conditions (such as temperature, humidity, vibration, etc.), even slight changes in environmental factors can affect the calibration results, resulting in frequent recalibration when testing in different environments, which seriously restricts the efficient application of photoacoustic spectrometers in practical scenarios.

[0003] Therefore, there is an urgent need for a photoacoustic spectroscopy device with closed-loop self-calibration to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide a photoacoustic spectroscopy gas measuring instrument with self-calibration function to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: The photoacoustic spectroscopy gas measuring instrument with self-calibration function includes a support plate. A laser, a photoacoustic cell, a multi-gas splitter, and a marking gas cell are mounted on the support plate. A first gas pump and a second gas pump are respectively mounted on both sides of the multi-gas splitter. The multi-gas splitter and the marking gas cell are connected via multiple gas pipes. A lens is installed between the laser and the photoacoustic cell. The outlet of the photoacoustic cell and the inlet of the first gas pump are connected via a first solenoid valve. The multi-gas splitter and the inlet of the first gas pump are connected via a second solenoid valve. The marking gas cell and the outlet of the second gas pump are connected via a third solenoid valve. The inlet of the photoacoustic cell and the outlet of the second gas pump are connected via a fourth solenoid valve. During measurement, the first gas pump and the fourth solenoid valve are opened to allow gas to enter a buffer tank for buffering before entering the photoacoustic cell. At this time, the first solenoid valve and the second gas pump are opened to maintain the same speed of the two gas pumps. Then, the laser is turned on, and the power between the optical paths is measured using two optical power meters. Attenuation is normalized, and photoacoustic signals are acquired through signal differential using a pressure-sensitive microphone. The acquired photoacoustic signals are compared with the measurement model to extract the concentration of the corresponding gas and other information to complete the measurement. During calibration, the corresponding standard gas is selected and configured in the calibration gas cell. The first gas pump and the fourth solenoid valve are started, while the second gas pump and the first solenoid valve are closed to complete the calibration buffer. Then, the first, second, third, and fourth solenoid valves are opened simultaneously, and the first and second gas pumps are opened to form an internal closed loop. The laser is then turned on, and the power attenuation between the optical path is measured and normalized using two optical power meters. The photoacoustic signals are acquired through signal differential using a pressure-sensitive microphone. The photoacoustic signal coefficients in the model are corrected successively using known gas concentrations and recorded in the measurement system. After completing a single calibration, the first gas pump and the third solenoid valve are closed. Finally, the standard gas is recirculated back to its original position using the second gas pump. After all measurements are completed, the closed-loop self-calibration of the system ends.

[0006] As a preferred technical solution, the air inlet end of the first air pump and the air outlet end of the second air pump are both equipped with buffer pools for stabilizing airflow, and pressure-sensitive microphones for detecting sound wave signals are installed on the air inlet end and the air outlet end of the photoacoustic pool. The support plate is equipped with a shell for protecting the components.

[0007] As a preferred technical solution, the housing is provided with a buffer component for reducing vibration during measurement, and the housing is also provided with a cleaning component for cleaning the optical window.

[0008] As a preferred technical solution, the buffer assembly includes a rubber clamp, an elastic pad, a cover, a piston, a push rod, and a spring; Rubber clamps are installed at the four corners of the support plate, and elastic pads are provided at the contact points between the rubber clamps and the support plate. The rubber clamps are slidably installed on the inner wall of the outer shell. A cover is installed directly below the rubber clamps, and a piston is slidably installed inside the cover. The bottom of the piston is connected to the bottom of the cover by a spring, and a push rod is installed on the top of the piston. The push rod passes through the top of the cover and is securely connected to the rubber clamps. When gas detection is performed and vibration is encountered, the rubber clamps first reduce the vibration transmitted to the support plate. Then, when the support plate slides up or down, the piston squeezes or stretches the spring and the conical support to further reduce the impact of vibration on the components on the support plate. At the same time, when the piston is pressed down, the air in the cover is squeezed into the hammer-shaped air bladder, so that the hammer-shaped air bladder supports the support plate and restricts the downward sliding of the support plate. Similarly, the principle is reversed when the piston moves up.

[0009] As a preferred technical solution, the buffer assembly further includes a conical support, a connecting block, and a hammer-shaped airbag; Four conical supports are symmetrically installed at the bottom of the outer shell. Each conical support has a chamber. A connecting block is installed at the top of the conical support and the top of the connecting block is connected to the bearing plate. An installation groove is provided at the top of the connecting block. A hammer-shaped airbag is installed in the installation groove. The hammer handle of the hammer-shaped airbag is located in the chamber. An air hole is provided on the cover and the air hole is connected to the pipe of the hammer-shaped airbag.

[0010] As a preferred technical solution, the tapered support is made of rubber.

[0011] As a preferred technical solution, the purging assembly includes a purger, a positioning block, a slot, a protective lens, a swing arm, and a drive box; A purger is installed at the optical window of both the laser and the photoacoustic cell. Each purger has a positioning block with a slot. A drive box is installed on the top of the housing, and two swing arms are rotatably mounted on the drive box. Protective lenses are mounted on both swing arms, and the protective lenses cooperate with the slots. When the measuring instrument is operating in a dusty area and the optical window becomes contaminated, the drive box controls the swing arms to move the protective lenses into the slots. Once fully in place, the purger activates. The blown air blades form an air curtain through the gap between the protective lenses and the optical window, ensuring that the light transmittance of the photoacoustic cell and the laser does not decrease beyond the self-calibrated light intensity compensation limit due to contamination.

[0012] As a preferred technical solution, the drive box includes a housing, a rotating frame, gears, a pawl, a rotating shaft, a ratchet, and a gear shaft; The top of the outer casing is fitted with a housing, inside which are installed two sets of rotating frames. Each set of rotating frames has a gear rotatably mounted on it. Each gear has a swing arm mounted on it, and multiple pawls are installed in the mounting holes of each gear. A rotating shaft is rotatably mounted inside the housing, passing through the pivot point of the two gears. Two ratchet wheels are mounted on the rotating shaft, and the two ratchet wheels and the two sets of pawls cooperate with each other in opposite directions. A gear shaft is rotatably mounted inside the housing, meshing with the two gears. When the optical window needs to be cleaned, the rotation direction of the rotating shaft is controlled to control the rotation of the gear closest to the photoacoustic cell or the laser, thereby allowing the corresponding protective lens to enter the slot for cleaning. When there is too much dust, the rotating shaft stops rotating, and the gear shaft is then controlled to rotate, causing the gear shaft to simultaneously drive the two gears to rotate, allowing both protective lenses to enter the slot for cleaning at the same time. This achieves cleaning of the optical window while reducing errors caused by the protective lenses.

[0013] As a preferred technical solution, optical power meters for monitoring lasers are installed on both sides of the photoacoustic cell.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. During calibration, this application selects and configures the corresponding standard gas in the calibration gas cell, starts the first gas pump and the fourth solenoid valve, and closes the second gas pump and the first solenoid valve to complete the calibration buffer. Then, the first, second, third and fourth solenoid valves are opened simultaneously, and the first and second gas pumps are opened to form an internal closed loop. Then, the laser is turned on, and the power attenuation between the optical paths is measured by two optical power meters and normalized. The photoacoustic signal is obtained by signal differential using a pressure-sensitive microphone. The photoacoustic signal coefficients in the model are corrected successively using known gas concentrations and recorded in the measurement system. After completing a single calibration, the first gas pump and the third solenoid valve are closed. Finally, the standard gas is recirculated to its original position using the second gas pump. After all measurements are completed, the closed-loop self-calibration correction of the system ends.

[0015] 2. When gas detection is encountered, the vibration is first initially reduced by the rubber clamp to the bearing plate. Then, when the bearing plate slides up or down, the vibration is further reduced by the piston squeezing or stretching the spring and the conical support. At the same time, when the piston is pressed down, the air in the cover is squeezed into the hammer-shaped air bag, so that the hammer-shaped air bag plays a supporting role for the bearing plate and restricts the bearing plate from sliding down. Similarly, the principle is the opposite when the piston moves up.

[0016] 3. In this application, when the measuring instrument is working in a dusty area and the optical window becomes contaminated, the drive box controls the swing arm to move the protective lens into the slot. After it is fully in, the blower is activated. At this time, the blown air blades form an air curtain under the action of the gap between the protective lens and the optical window, thereby ensuring that the optical window of the photoacoustic cell and the laser will not have its light transmittance decrease beyond the self-calibrated light intensity compensation limit due to contamination. When the optical window needs to be blown, the rotation direction of the rotating shaft is controlled to control the rotation of the gear that is closer to the photoacoustic cell or the laser, so that the corresponding protective lens enters the slot for blowing. When there is too much dust, the rotating shaft stops rotating. At this time, the gear shaft is controlled to rotate, so that the gear shaft drives the two gears to rotate at the same time, so that the two protective lenses enter the slot at the same time for blowing, thereby cleaning the optical window and reducing the error caused by the protective lens. Attached Figure Description

[0017] Figure 1 This is an overall schematic diagram of the present invention; Figure 2 This is a schematic diagram of the internal first-view structure of the present invention; Figure 3 This is a schematic diagram of the internal second-view structure of the present invention; Figure 4 This is a schematic diagram of the internal third-view structure of the present invention; Figure 5 This is a schematic diagram of the purging assembly structure of the present invention; Figure 6 This is a schematic diagram of the internal structure of the drive box of the present invention; Figure 7 for Figure 4 Enlarged structural diagram at point A; Figure 8 for Figure 4 A magnified structural diagram at point B in the middle.

[0018] In the diagram: 1. Support plate; 2. Laser; 3. Lens; 4. Photoacoustic cell; 5. Pressure-sensitive microphone; 6. First air pump; 61. Second air pump; 7. Buffer pool; 8. First solenoid valve; 81. Second solenoid valve; 82. Third solenoid valve; 83. Fourth solenoid valve; 9. Multi-gas splitter; 10. Standard gas cell; 11. Housing; 12. Optical power meter; 20. Buffer assembly; 21. Rubber clamp; 22. Elastic pad; 23. Cover; 231. Air vent; 24. Piston; 25. Push rod; 26. Spring; 27. Conical support; 271. Chamber; 28. Connecting block; 281. Mounting groove; 29. ​​Hammer-shaped airbag; 30. Blowing assembly; 31. Blower; 32. Positioning block; 33. Slot; 34. Protective lens; 35. Swing arm; 36. Drive box; 361. Housing; 362. Rotating frame; 363. Gear; 364. Pawl; 365. Shaft; 366. Ratchet; 367. Gear shaft. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example: Figures 1-3As shown, this invention provides a technical solution for a photoacoustic spectroscopy gas measuring instrument with self-calibration function. This instrument includes a support plate 1, on which a laser 2, a photoacoustic cell 4, a multi-gas splitter 9, and a marking gas cell 10 are mounted. A first gas pump 6 and a second gas pump 61 are respectively mounted on both sides of the multi-gas splitter 9. The multi-gas splitter 9 and the marking gas cell 10 are connected by multiple gas pipes. A lens 3 is installed between the laser 2 and the photoacoustic cell 4. The gas outlet of the photoacoustic cell 4 and the gas inlet of the first gas pump 6 are connected by a first solenoid valve 8. The multi-gas splitter 9 and the inlet of the first gas pump 6 are connected via a second solenoid valve 81. The gas separator 10 and the outlet of the second gas pump 61 are connected via a third solenoid valve 82. The inlet of the photoacoustic cell 4 and the outlet of the second gas pump 61 are connected via a fourth solenoid valve 83. During measurement, the first gas pump 6 and the fourth solenoid valve 83 are opened, allowing gas to be buffered in the buffer tank 7 before entering the photoacoustic cell 4. At this time, the first solenoid valve 8 and the second gas pump 61 are opened to maintain the same speed for both pumps. Then, the laser 2 is turned on, and the measurement is performed using two optical power meters 12. The power attenuation between optical paths is normalized. A pressure-sensitive microphone 5 is used to acquire the photoacoustic signal through signal differential analysis. The acquired photoacoustic signal is compared with the measurement model to extract the concentration of the corresponding gas and other information, thus completing the measurement. During calibration, the corresponding standard gas is selected and configured in the calibration gas cell 10. The first gas pump 6 and the fourth solenoid valve 83 are started, while the second gas pump 61 and the first solenoid valve 8 are closed to complete the calibration buffer. Then, the first solenoid valve 8, the second solenoid valve 81, the third solenoid valve 82, and the fourth solenoid valve 83 are opened simultaneously. The first air pump 6 and the second air pump 61 form an internal closed loop. Then, the laser 2 is turned on, and the power attenuation between the optical paths is measured and normalized using two optical power meters 12. The photoacoustic signal is obtained by signal differential using a pressure-sensitive microphone 5. The photoacoustic signal coefficients in the model are corrected successively using known gas concentrations and recorded in the measurement system. After completing a single calibration, the first air pump 6 and the third solenoid valve 82 are turned off. Finally, the standard gas is recirculated to its original position using the second air pump 61. After all measurements are completed, the closed-loop self-calibration correction of the system ends.

[0021] The first air pump 6 and the second air pump 61 are both equipped with buffer pools 7 for stabilizing airflow. The photoacoustic pool 4 is equipped with pressure-sensitive microphones 5 for detecting sound wave signals at both the air inlet and outlet. The support plate 1 is equipped with a housing 11 for protecting the components.

[0022] The housing 11 is equipped with a buffer assembly 20 for reducing vibration during measurement, and a cleaning assembly 30 for cleaning the optical window.

[0023] like Figure 4 , Figure 7 and Figure 8As shown, the buffer assembly 20 includes a rubber clamp 21, an elastic pad 22, a cover 23, a piston 24, a push rod 25, and a spring 26; Rubber clamps 21 are installed at each of the four corners of the support plate 1. Elastic pads 22 are provided at the contact points between the rubber clamps 21 and the support plate 1. The rubber clamps 21 are slidably mounted on the inner wall of the outer casing 11. A cover 23 is installed directly below the rubber clamps 21. A piston 24 is slidably mounted inside the cover 23. The bottom of the piston 24 is connected to the bottom of the cover 23 by a spring 26. A push rod 25 is installed on the top of the piston 24, passing through the top of the cover 23 and securely connected to the rubber clamps 21. When gas detection is performed... When vibration is encountered, the vibration is first initially reduced to the bearing plate 1 by the rubber clamp 21. Then, when the bearing plate 1 slides up or down, the vibration is further reduced to the components on the bearing plate 1 by the piston 24 squeezing or stretching the spring 26 and the conical support 27. At the same time, when the piston 24 presses down, the air in the cover 23 is squeezed into the hammer-shaped airbag 29, so that the hammer-shaped airbag 29 plays a supporting role for the bearing plate 1 and restricts the bearing plate 1 from sliding down. Similarly, the principle is the opposite when the piston 24 moves up.

[0024] The buffer assembly 20 also includes a conical support 27, a connecting block 28, and a hammer-shaped airbag 29; Four conical supports 27 are symmetrically installed at the bottom of the outer shell 11. A chamber 271 is opened inside the conical support 27. A connecting block 28 is installed at the top of the conical support 27, and the top of the connecting block 28 is connected to the bearing plate 1. An installation groove 281 is opened at the top of the connecting block 28. A hammer-shaped airbag 29 is installed in the installation groove 281. The hammer handle of the hammer-shaped airbag 29 is located in the chamber 271. An air hole 231 is opened on the cover 23, and the air hole 231 is connected to the pipe of the hammer-shaped airbag 29.

[0025] The tapered support 27 is made of rubber.

[0026] like Figure 2 , Figure 5 and Figure 6 As shown, the purging assembly 30 includes a purger 31, a positioning block 32, a slot 33, a protective lens 34, a swing arm 35, and a drive box 36; A purger 31 is installed at the optical window of both the laser 2 and the photoacoustic cell 4. A positioning block 32 is installed on each purger 31, and a slot 33 is opened on the positioning block 32. A drive box 36 is installed on the top of the housing 11. Two swing arms 35 are rotatably installed on the drive box 36. A protective lens 34 is installed on each swing arm 35. The protective lens 34 and the slot 33 cooperate with each other. When the measuring instrument is working in a dusty area and the optical window is contaminated, the drive box 36 controls the swing arm 35 to drive the protective lens 34 into the slot 33. After it is fully inserted, the purger 31 is activated. At this time, the blown air blade forms an air curtain under the action of the gap between the protective lens 34 and the optical window, thereby ensuring that the optical window of the photoacoustic cell 4 and the laser 2 will not reduce the light transmittance due to contamination and exceed the upper limit of the self-calibrated light intensity compensation.

[0027] The drive box 36 includes a box body 361, a rotating frame 362, a gear 363, a pawl 364, a rotating shaft 365, a ratchet 366, and a gear shaft 367; A housing 361 is mounted on the top of the outer casing 11. Two sets of rotating brackets 362 are installed inside the housing 361. A gear 363 is rotatably mounted on each set of rotating brackets 362. A rocker arm 365 is mounted on each of the two gears 363. Multiple pawls 364 are installed in the mounting holes of each of the two gears 363. A rotating shaft 365 is rotatably mounted inside the housing 361, passing through the rotating center of the two gears 363. Two ratchet wheels 366 are mounted on the rotating shaft 365. The two ratchet wheels 366 and the two sets of pawls 364 cooperate with each other, with the meshing directions of the two sets of ratchet wheels 366 and pawls 364 being opposite. The rotating shaft 365... Equipped with a gear shaft 367, which meshes with two gears 363, when the optical window needs to be cleaned, the rotation direction of the rotating shaft 365 is controlled to control the rotation of the gear 363 closest to the photoacoustic cell 4 or the laser 2, thereby causing the corresponding protective lens 34 to enter the slot 33 for cleaning. When there is too much dust, the rotating shaft 365 stops rotating. At this time, the gear shaft 367 is controlled to rotate, so that the gear shaft 367 drives the two gears 363 to rotate simultaneously, causing the two protective lenses 34 to enter the slot 33 simultaneously for cleaning, thus cleaning the optical window while reducing the error caused by the protective lens 34.

[0028] Optical power meters 12 for monitoring lasers are installed on both sides of the photoacoustic cell 4.

[0029] Working principle of the invention: During measurement, the first air pump 6 and the fourth solenoid valve 83 are opened to allow gas to pass through the buffer tank 7 for buffering before entering the photoacoustic cell 4. At this time, the first solenoid valve 8 and the second air pump 61 are opened to maintain the same pump speed. Then, the laser 2 is turned on, and the power attenuation between optical paths is measured and normalized using two optical power meters 12. The photoacoustic signal is acquired through signal differential analysis using a pressure-sensitive microphone 5. The acquired photoacoustic signal is compared with the measurement model to extract the concentration of the corresponding gas and other information, thus completing the measurement. During calibration, the corresponding standard gas is selected and configured in the standard gas cell 10. The first air pump 6 and the fourth solenoid valve 83 are started, while the second air pump 61 and the first solenoid valve 83 are closed. After completing the calibration buffer, the first solenoid valve 8, the second solenoid valve 81, the third solenoid valve 82, and the fourth solenoid valve 83 are opened simultaneously, and the first air pump 6 and the second air pump 61 are opened to form an internal closed loop. Then, the laser 2 is turned on, and the power attenuation between the optical paths is measured by two optical power meters 12 and normalized. The photoacoustic signal is obtained by signal differential using the pressure-sensitive microphone 5. The photoacoustic signal coefficients in the model are corrected successively using the known gas concentration and recorded in the measurement system. After completing a single calibration, the first air pump 6 and the third solenoid valve 82 are closed. Finally, the standard gas is recirculated to its original position using the second air pump 61. After all measurements are completed, the closed-loop self-calibration correction of the system ends.

[0030] When gas detection is encountered, vibration is first initially reduced by the rubber clamp 21 to reduce the vibration transmitted to the support plate 1. Then, when the support plate 1 slides up or down, the piston 24 squeezes or stretches the spring 26 and the conical support 27 to further reduce the impact of vibration on the components on the support plate 1. At the same time, when the piston 24 presses down, the air in the cover 23 is squeezed into the hammer-shaped airbag 29, so that the hammer-shaped airbag 29 plays a supporting role for the support plate 1 and restricts the support plate 1 from sliding down. Similarly, the principle is the opposite when the piston 24 moves up.

[0031] When the measuring instrument is working in a dusty area and the optical window becomes contaminated, the drive box 36 controls the swing arm 35 to drive the protective lens 34 into the slot 33. After it is fully in, the blower 31 is activated. At this time, the blown air blades form an air curtain under the action of the gap between the protective lens 34 and the optical window, thereby ensuring that the optical windows of the photoacoustic cell 4 and the laser 2 will not have their light transmittance reduced beyond the self-calibrated light intensity compensation limit due to contamination. When the optical window needs to be blown, the rotation direction of the rotating shaft 365 is controlled to control the rotation of the gear 363 that is closer to the photoacoustic cell 4 or the laser 2, so that the corresponding protective lens 34 enters the slot 33 for blowing. When there is too much dust, the rotating shaft 365 stops rotating. At this time, the gear shaft 367 is controlled to rotate, so that the gear shaft 367 drives the two gears 363 to rotate at the same time, so that the two protective lenses 34 enter the slot 33 at the same time for blowing, thereby cleaning the optical window and reducing the error caused by the protective lens 34.

[0032] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A photoacoustic spectroscopy gas measuring instrument with self-calibration function, characterized in that: The photoacoustic spectroscopy gas measuring instrument with self-calibration function includes a support plate (1). A laser (2), a photoacoustic cell (4), a multi-gas splitter (9), and a labeling gas cell (10) are installed on the support plate (1). A first gas pump (6) and a second gas pump (61) are installed on both sides of the multi-gas splitter (9). The multi-gas splitter (9) and the labeling gas cell (10) are connected by multiple gas pipes. A lens (3) is installed between the laser (2) and the photoacoustic cell (4). The outlet of the photoacoustic cell (4) and the inlet of the first gas pump (6) are connected by a first solenoid valve (8). The multi-gas splitter (9) and the inlet of the first gas pump (6) are connected by a second solenoid valve (81). The outlet of the labeling gas cell (10) and the second gas pump (61) are connected by a third solenoid valve (82). The inlet of the photoacoustic cell (4) and the outlet of the second gas pump (61) are connected by a fourth solenoid valve (83).

2. The photoacoustic spectrometer with self-calibration function according to claim 1, characterized in that: The first air pump (6) and the second air pump (61) are both equipped with a buffer pool (7) for stabilizing airflow. The photoacoustic pool (4) is equipped with a pressure-sensitive microphone (5) for detecting sound wave signals at both the air inlet and outlet. The support plate (1) is equipped with a housing (11) for protecting the components.

3. A photoacoustic spectrometer with self-calibration function according to claim 2, characterized in that: The housing (11) is provided with a buffer assembly (20) for reducing vibration during measurement, and the housing (11) is also provided with a cleaning assembly (30) for cleaning the optical window.

4. A photoacoustic spectrometer with self-calibration function according to claim 3, characterized in that: The buffer assembly (20) includes a rubber clamp (21), an elastic pad (22), a cover (23), a piston (24), a push rod (25), and a spring (26). Rubber clamps (21) are installed at the four corners of the bearing plate (1). Elastic pads (22) are provided at the contact points between the rubber clamps (21) and the bearing plate (1). The rubber clamps (21) are slidably installed on the inner wall of the outer shell (11). A cover (23) is installed directly below the rubber clamps (21). A piston (24) is slidably installed inside the cover (23). The bottom of the piston (24) is connected to the bottom of the cover (23) by a spring (26). A push rod (25) is installed on the top of the piston (24). The push rod (25) passes through the top of the cover (23) and is fastened to the rubber clamps (21).

5. A photoacoustic spectrometer with self-calibration function according to claim 4, characterized in that: The buffer assembly (20) also includes a conical support (27), a connecting block (28), and a hammer-shaped airbag (29). The bottom of the outer shell (11) is symmetrically equipped with four conical supports (27), each conical support (27) has a chamber (271) inside, and a connecting block (28) is installed on the top of the conical support (27). The top of the connecting block (28) is connected to the bearing plate (1). The top of the connecting block (28) has an installation groove (281). A hammer-shaped airbag (29) is installed in the installation groove (281). The hammer handle of the hammer-shaped airbag (29) is located in the chamber (271). An air hole (231) is opened on the cover (23), and the air hole (231) is connected to the pipe of the hammer-shaped airbag (29).

6. A photoacoustic spectrometer with self-calibration function according to claim 5, characterized in that: The tapered support (27) is made of rubber.

7. A photoacoustic spectrometer with self-calibration function according to claim 3, characterized in that: The purging assembly (30) includes a purger (31), a positioning block (32), a slot (33), a protective lens (34), a swing arm (35), and a drive box (36). A purger (31) is installed at the optical window of both the laser (2) and the photoacoustic cell (4). A positioning block (32) is installed on each of the two purgers (31). A slot (33) is provided on the positioning block (32). A drive box (36) is installed on the top of the outer shell (11). Two swing arms (35) are rotatably installed on the drive box (36). A protective lens (34) is installed on each of the two swing arms (35). The protective lens (34) cooperates with the slot (33).

8. A photoacoustic spectrometer with self-calibration function according to claim 7, characterized in that: The drive box (36) includes a box body (361), a rotating frame (362), a gear (363), a pawl (364), a rotating shaft (365), a ratchet (366), and a gear shaft (367). The top of the outer casing (11) is fitted with a housing (361), and two sets of rotating frames (362) are installed inside the housing (361). Each set of rotating frames (362) is rotatably fitted with a gear (363). Each of the two gears (363) is fitted with a rocker arm (35). Multiple pawls (364) are installed in the mounting holes of the two gears (363). A rotating shaft (365) is rotatably fitted inside the housing (361). The rotating shaft (365) passes through the rotating center of the two gears (363). Two ratchet wheels (366) are mounted on the rotating shaft (365). The two ratchet wheels (366) and the two sets of pawls (364) cooperate with each other. The two sets of ratchet wheels (366) and pawls (364) mesh in opposite directions. A gear shaft (367) is rotatably fitted inside the housing (361). The gear shaft (367) meshes with the two gears (363).

9. A photoacoustic spectrometer with self-calibration function for gas measurement according to claim 1, characterized in that: Both sides of the photoacoustic cell (4) are equipped with optical power meters (12) for monitoring lasers.

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