A small multi-gas detection system based on incoherent broadband cavity enhanced technology

Abstract

The present invention provides a small multi-gas detection system based on incoherent broadband cavity enhanced technology, which relates to the technical field of gas detection. The system includes a first gas analysis component, a second gas analysis component and a detection component. The first gas analysis component and the second gas analysis component have the same structure and are arranged in parallel. In the present invention, several components such as a radiation source component, an incoherent broadband component, a light source focusing component and a detection component are integrated together, and the detection of gas signals can be completed within one instrument. Compared with the traditional detection form in which the optical path after absorption needs to be introduced into the spectrum through an optical fiber or a retroreflector, the volume and integration degree of the instrument are greatly reduced, realizing the miniaturization of the incoherent broadband cavity enhanced absorption spectroscopy technology as a highly sensitive optical detector, meeting the advantages of high sensitivity, small volume and short response time, and adapting to the complex and changeable gas detection requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas detection, and particularly relates to a small multi-gas detection system based on incoherent broadband cavity enhanced technology. Background Technique

[0002] With the rapid development of fields such as environmental science, industrial safety, and aerospace, the requirements for gas detection technology are getting higher and higher; traditional gas detection methods, such as electrochemistry and chromatography, although to a certain extent can detect specific gases, often have limitations such as low sensitivity, large volume, and long response time, and it is difficult to meet the complex and changeable detection requirements;

[0003] As a highly sensitive optical detection method, incoherent broadband cavity enhanced absorption spectroscopy has received extensive attention in recent years; this technology can effectively increase the absorption optical path by constructing an optical resonator composed of high-reflectivity lenses, thereby improving the detection sensitivity of the gas to be measured; at the same time, due to the use of incoherent broadband light sources, this technology can realize the simultaneous detection of multiple gases, providing the possibility for gas analysis in complex environments; for the current incoherent broadband cavity enhanced absorption spectroscopy technology, it can be divided into the ultraviolet band region and the infrared band region according to the detected gas. In the ultraviolet band region, an LED is often used as the light source. After the absorption path of the optical resonator is increased, the light carrying gas information is introduced into the spectrometer for analysis to obtain the absorption information of the corresponding gas; in the infrared band, a tungsten halogen lamp, a quantum cascade laser, and an SC light source are often used as infrared light sources. After the absorption path of the optical resonator is increased, the light carrying gas information is introduced into the Fourier transform spectrometer for analysis to obtain the corresponding gas absorption information; when the existing instruments based on the incoherent cavity enhancement principle obtain the gas concentration absorption information, they often need to solve the absorbed optical information through spectral analysis, which requires a large amount of calculation, uses more instruments in the processing process, and the used instruments have a large volume, and it is difficult to be effectively applied in the actual measurement environment.

[0004] Therefore, it is very necessary to invent a small multi-gas detection system based on incoherent broadband cavity enhanced technology. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a small multi-gas detection system based on incoherent broadband cavity enhancement technology to solve the technical problems mentioned in the background art section. A small multi-gas detection system based on incoherent broadband cavity enhancement technology includes a first gas analysis component, a second gas analysis component, a detection component, and a data acquisition end. The first gas analysis component and the second gas analysis component have the same structure and are arranged in parallel. The detection component is installed at the ends of the first gas analysis component and the second gas analysis component. The data acquisition end is arranged on the side of the detection component away from the first gas analysis component. The data acquisition end is connected to the mains, a temperature and pressure sensor, and a dual-channel infrared detector through wires, and the data acquisition end collects the temperature and pressure information transmitted by the temperature and pressure sensor and the electrical signal information containing gas concentration information transmitted by the dual-channel infrared detector. By arranging the first gas analysis component and the second gas analysis component with the same structure and replacing the dual-channel infrared detector with different wavelength bands, the simultaneous detection of multi-component gases can be achieved.

[0006] The first gas analysis component includes a radiation source component, an incoherent broadband component, and a light source focusing component. The incoherent broadband component is installed on the side of the radiation source component close to the detection component. The light source focusing component is installed on the side of the incoherent broadband component close to the detection component. Integrating several parts such as the radiation source component, the incoherent broadband component, the light source focusing component, and the detection component together, the detection of gas signals can be completed within one instrument. Compared with the traditional detection form that needs to introduce the absorbed optical path into the spectrum through optical fibers or retroreflectors, the volume and integration degree of the instrument are greatly reduced, realizing the miniaturization of the incoherent broadband cavity enhanced absorption spectroscopy technology as a high-sensitivity optical detector, meeting the advantages of high sensitivity, small volume, short response time, etc., and adapting to the complex and changeable gas detection requirements.

[0007] The radiation source component includes a light source collimation cavity, an infrared radiation source, a radiation source window piece, and an air inlet. The infrared radiation source is installed on the side of the light source collimation cavity away from the detection component, and the end of the infrared radiation source is located inside the light source collimation cavity. The radiation source window piece is installed on the side of the infrared radiation source close to the detection component. The air inlet is opened on the upper side of the light source collimation cavity. A sealing ring is arranged at the connection between the light source collimation cavity and the infrared radiation source. The infrared radiation source adopts one of an LED light source, an SC light source, and a tungsten halogen light source. The radiation source window piece is used to reduce the influence of the sampling gas entering from the air inlet on the light source of the infrared radiation source. The air inlet is connected to an external pump through a pipeline.

[0008] Preferably, the incoherent broadband component includes an incoherent broadband cavity, a plano-convex collimating lens, a first plano-concave reflector, a temperature and pressure sensor, a second plano-concave reflector, and a first-stage focusing lens. The incoherent broadband cavity is installed on one side of the light source collimating cavity close to the detection component; the temperature and pressure sensor is installed on the upper side of the incoherent broadband cavity, and the detection probe of the temperature and pressure sensor is located inside the incoherent broadband cavity; the plano-convex collimating lens is installed on one side of the inside of the incoherent broadband cavity close to the light source collimating cavity; the first plano-concave reflector is installed on the side of the plano-convex collimating lens facing away from the light source collimating cavity; the first-stage focusing lens is installed inside the incoherent broadband cavity on the side facing away from the light source collimating cavity; the second plano-concave reflector is installed on the side of the first-stage focusing lens close to the light source collimating cavity; ventilation holes are uniformly arranged at the connection between the incoherent broadband cavity and the light source collimating cavity, and the uniformly arranged ventilation holes enable the sampling gas to quickly flush the incoherent broadband cavity; the temperature and pressure sensor is connected to the mains through a wire.

[0009] Preferably, the light source focusing component includes a light source focusing cavity, an air outlet, and a second-stage focusing lens. The light source focusing cavity is installed on one side of the incoherent broadband cavity facing away from the light source collimating cavity; the air outlet is opened on the upper side of the light source focusing cavity; the second-stage focusing lens is installed inside the light source focusing cavity on the side facing away from the incoherent broadband cavity; ventilation holes are uniformly arranged at the connection between the light source focusing cavity and the incoherent broadband cavity; a one-way valve is provided at the air outlet to prevent gas from flowing back into the inside of the light source focusing cavity; the second-stage focusing lens, the infrared radiation source, the radiation source window plate, the plano-convex collimating lens, the first plano-concave reflector, the second plano-concave reflector, and the first-stage focusing lens adopt a coaxial optical path design.

[0010] Preferably, the detection component includes a signal detection cavity, a stepping motor, a dual-channel infrared detection component, and a chopping modulation sheet. The signal detection cavity is on the side of the light source focusing cavity facing away from the light source focusing cavity; the stepping motor is installed at the middle position on the side of the inside of the signal detection cavity facing away from the light source focusing cavity; the chopping modulation sheet is installed on the output shaft of the stepping motor; two dual-channel infrared detection components are adopted, and the dual-channel infrared detection components are installed inside the signal detection cavity, and the dual-channel infrared detection components are located on the side of the chopping modulation sheet facing away from the light source focusing cavity; ventilation holes are uniformly arranged at the connection between the signal detection cavity and the light source focusing cavity; the stepping motor is connected to the mains through a wire; the chopping modulation sheet is driven by the stepping motor to rotate to chop and modulate the light beam; the entire detection system adopts a fully enclosed detection cavity and a unique gas path layout. Compared with the traditional method of placing the air inlet and outlet on the incoherent broadband cavity, it effectively utilizes the absorption optical path of the light source collimating cavity and the light source focusing cavity parts, eliminates the airflow dead angle of the detection system at the same time, speeds up the response time of the detection system, and makes the measurement result more accurate.

[0011] Preferably, the dual-channel infrared detection component includes a dual-channel infrared detector, a gas measurement channel, a light spot, and a gas reference channel. Two dual-channel infrared detectors are used, and the dual-channel infrared detectors are installed inside the signal detection cavity. The dual-channel infrared detectors are located on the side of the chopping modulation sheet away from the light source focusing cavity. The dual-channel infrared detectors are connected to the mains through wires and are used to convert the modulated light beam into an electrical signal after receiving it. The dual-channel infrared detectors adopt a polarization-axis offset design with a plano-convex collimating lens and a first plano-concave reflector; the gas measurement channel, the light spot, and the gas reference channel are located on the side of the dual-channel infrared detector close to the light source focusing cavity; the dual-channel infrared detectors adopt a polarization-axis offset design method. Compared with the general coaxial design, the off-axis design method enables the gas absorption channel to obtain a higher signal value, making it more sensitive to changes in gas concentration, and improving the sensitivity of the instrument while improving the detection accuracy.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] 1. In the present invention, several components such as the radiation source component, the incoherent broadband component, the light source focusing component, and the detection component are integrated together, and the detection of gas signals can be completed within one instrument. Compared with the traditional detection form in which the absorbed optical path needs to be introduced into the spectrum through optical fibers or folding mirrors, the volume and integration degree of the instrument are greatly reduced, realizing the miniaturization of the incoherent broadband cavity-enhanced absorption spectroscopy technology as a high-sensitivity optical detector, meeting the advantages of high sensitivity, small volume, short response time, etc., and adapting to the complex and changeable gas detection requirements;

[0014] 2. In the present invention, the uniquely designed way to improve the air intake of the optical cavity is to arrange uniformly distributed vent holes connected to the optical cavity around the cavity mirror. Through this arrangement, the sample gas can quickly purge the gas chamber of the optical cavity, realizing the rapid replacement of the gas to be measured in the gas chamber; compared with the traditional method of placing the air inlet and outlet ends on the incoherent broadband cavity, changing the traditional side air intake to end face air intake improves the eddy current distribution caused by side air intake and eliminates the dead zone of concentration exchange, increasing the concentration balance response speed by 8.75 times. This is crucial for improving the spatial resolution of the instrument, enabling the instrument to more effectively respond to the measurement of gas concentration during rapid movement, accelerating the response time of the detection system, and making the measurement results more accurate;

[0015] 3. In the present invention, the dual-channel infrared detectors adopt a polarization-axis offset design method. Compared with the general coaxial design, the off-axis design method enables the gas absorption channel to obtain a higher signal value, making it more sensitive to changes in gas concentration, and improving the sensitivity of the instrument while improving the detection accuracy;

[0016] 4. In the present invention, by arranging the first gas analysis component and the second gas analysis component with the same structure, and replacing the dual-channel infrared detectors with different wavelength bands, the simultaneous detection of multi-component gases can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the present invention.

[0018] Figure 2 is a schematic structural diagram of the interior of the present invention.

[0019] Figure 3 is a schematic structural diagram of the dual-channel infrared detection component of the present invention.

[0020] In the figure:

[0021] 1. First gas analysis component; 2. Second gas analysis component; 3. Radiation source component; 31. Light source collimation cavity; 32. Infrared radiation source; 33. Radiation source window piece; 34. Air inlet; 4. Incoherent broadband component; 41. Incoherent broadband cavity; 42. Plano-convex collimating lens; 43. First plano-concave reflector; 44. Temperature and pressure sensor; 45. Second plano-concave reflector; 46. First-stage focusing lens; 5. Light source focusing component; 51. Light source focusing cavity; 52. Air outlet; 53. Second-stage focusing lens; 6. Detection component; 61. Signal detection cavity; 62. Stepper motor; 63. Dual-channel infrared detection component; 631. Dual-channel infrared detector; 632. Gas measurement channel; 633. Light spot; 634. Gas reference channel; 64. Chopper modulation piece; 7. Data acquisition terminal. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The present invention will be further described below with reference to the accompanying drawings:

[0023] Embodiment:

[0024] As shown in the attached Figure 1 to the attached Figure 3 figure

[0025] The present invention provides a small multi-gas detection system based on incoherent broadband cavity enhancement technology, comprising a first gas analysis component 1, a second gas analysis component 2, a detection component 6 and a data acquisition terminal 7. The first gas analysis component 1 and the second gas analysis component 2 adopt the same structure, and the first gas analysis component 1 and the second gas analysis component 2 are arranged in parallel; the detection component 6 is installed at the ends of the first gas analysis component 1 and the second gas analysis component 2; the data acquisition terminal 7 is arranged on the side of the detection component 6 away from the first gas analysis component 1; the data acquisition terminal 7 is connected to the mains, a temperature and pressure sensor 44 and a dual-channel infrared detector 631 through wires, and the data acquisition terminal 7 collects the temperature and pressure information transmitted by the temperature and pressure sensor 44 and the electrical signal information containing gas concentration information transmitted by the dual-channel infrared detector 631.

[0026] In this embodiment, the first gas analysis component 1 includes a radiation source component 3, an incoherent broadband component 4 and a light source focusing component 5. The incoherent broadband component 4 is installed on a side of the radiation source component 3 close to the detection component 6; the light source focusing component 5 is installed on a side of the incoherent broadband component 4 close to the detection component 6;

[0027] In this embodiment, the radiation source assembly 3 includes a light source collimating cavity 31, an infrared radiation source 32, a radiation source window 33 and an air inlet 34. The infrared radiation source 32 is installed on the side of the light source collimating cavity 31 away from the detection assembly 6, and the end of the infrared radiation source 32 is located inside the light source collimating cavity 31; the radiation source window 33 is installed on the side of the infrared radiation source 32 close to the detection assembly 6; the air inlet 34 is opened on the upper side of the light source collimating cavity 31; a sealing ring is provided at the connection between the light source collimating cavity 31 and the infrared radiation source 32; the infrared radiation source 32 adopts one of an LED light source, an SC light source, and a halogen tungsten lamp light source; the radiation source window 33 is used to reduce the influence of the sampling gas entering from the air inlet 34 on the light source of the infrared radiation source 32; the air inlet 34 is connected to an external pump through a pipeline.

[0028] In this embodiment, the incoherent broadband component 4 includes an incoherent broadband cavity 41, a plano-convex collimating lens 42, a first plano-concave reflector 43, a temperature and pressure sensor 44, a second plano-concave reflector 45, and a first-stage focusing lens 46. The incoherent broadband cavity 41 is installed on one side of the light source collimating cavity 31 close to the detection component 6; the temperature and pressure sensor 44 is installed on the upper side of the incoherent broadband cavity 41, and the detection probe of the temperature and pressure sensor 44 is located inside the incoherent broadband cavity 41; the plano-convex collimating lens 42 is installed on one side of the inside of the incoherent broadband cavity 41 close to the light source collimating cavity 31; the first plano-concave reflector 43 is installed on the side of the plano-convex collimating lens 42 facing away from the light source collimating cavity 31; the first-stage focusing lens 46 is installed inside the incoherent broadband cavity 41 on the side facing away from the light source collimating cavity 31; the second plano-concave reflector 45 is installed on the side of the first-stage focusing lens 46 close to the light source collimating cavity 31; uniformly arranged ventilation holes are provided at the connection between the incoherent broadband cavity 41 and the light source collimating cavity 31, and the uniformly arranged ventilation holes enable the sampling gas to quickly flush the incoherent broadband cavity 41; the temperature and pressure sensor 44 is connected to the mains through a wire.

[0029] In this embodiment, the light source focusing component 5 includes a light source focusing cavity 51, an air outlet 52, and a second-stage focusing lens 53. The light source focusing cavity 51 is installed on the side of the incoherent broadband cavity 41 facing away from the light source collimating cavity 31; the air outlet 52 is provided on the upper side of the light source focusing cavity 51; the second-stage focusing lens 53 is installed inside the light source focusing cavity 51 on the side facing away from the incoherent broadband cavity 41; uniformly arranged ventilation holes are provided at the connection between the light source focusing cavity 51 and the incoherent broadband cavity 41; a one-way valve is provided at the air outlet 52 to prevent gas from flowing back into the inside of the light source focusing cavity 51; the second-stage focusing lens 53, the infrared radiation source 32, the radiation source window piece 33, the plano-convex collimating lens 42, the first plano-concave reflector 43, the second plano-concave reflector 45, and the first-stage focusing lens 46 adopt a coaxial optical path design.

[0030] In this embodiment, the detection component 6 includes a signal detection cavity 61, a stepping motor 62, a dual-channel infrared detection component 63, and a chopping modulation sheet 64. The signal detection cavity 61 is on the side of the light source focusing cavity 51 facing away from the light source focusing cavity 51; the stepping motor 62 is installed at the middle position inside the signal detection cavity 61 on the side facing away from the light source focusing cavity 51; the chopping modulation sheet 64 is installed on the output shaft of the stepping motor 62; two dual-channel infrared detection components 63 are adopted, and the dual-channel infrared detection components 63 are installed inside the signal detection cavity 61, and the dual-channel infrared detection components 63 are located on the side of the chopping modulation sheet 64 facing away from the light source focusing cavity 51; uniformly arranged ventilation holes are provided at the connection between the signal detection cavity 61 and the light source focusing cavity 51; the stepping motor 62 is connected to the mains through a wire; the chopping modulation sheet 64 is driven by the stepping motor 62 to rotate to chop and modulate the light beam.

[0031] In this embodiment, the dual-channel infrared detection component 63 includes a dual-channel infrared detector 631, a gas measurement channel 632, a light spot 633, and a gas reference channel 634. Two dual-channel infrared detectors 631 are used, and the dual-channel infrared detectors 631 are installed inside the signal detection cavity 61. The dual-channel infrared detectors 631 are located on the side of the chopper modulation sheet 64 away from the light source focusing cavity 51. The dual-channel infrared detectors 631 are connected to the mains through wires, and the dual-channel infrared detectors 631 are used to convert the modulated light beam into an electrical signal after receiving it. The dual-channel infrared detectors 631 adopt a polarization axis design with the plano-convex collimating lens 42 and the first plano-concave reflector 43; the gas measurement channel 632, the light spot 633, and the gas reference channel 634 are located on the side of the dual-channel infrared detectors 631 close to the light source focusing cavity 51.

[0032] Working principle

[0033] In the present invention, during the sampling process, the gas to be measured is pumped through the intake port 34 into the light source collimation cavity 31 by an external pump. The gas entering the light source collimation cavity 31 enters the incoherent broadband cavity 41 through the uniformly distributed small holes connecting the light source collimation cavity 31 and the incoherent broadband cavity 41. After the gas uniformly fills the incoherent broadband cavity 41, it enters the light source focusing cavity 51 through the uniformly distributed small holes connecting the incoherent broadband cavity 41 and the light source focusing cavity 51, and then is discharged through the outlet port 52.

[0034] During the gas measurement process, the infrared radiation emitted by the infrared radiation source 32 passes through the radiation source window sheet 33 and enters the light source collimation cavity 31. Then, the light beam collimated by the plano-convex collimating lens 42 passes through the second plano-concave reflector 45 and is reflected multiple times in the incoherent broadband cavity 41 composed of the first plano-concave reflector 43 and the second plano-concave reflector 45. Each reflection will have part of the light pass through the second plano-concave reflector 45 and pass through the first-stage focusing lens 46 and the second-stage focusing lens 53. The light source is focused by the first-stage focusing lens 46 and the second-stage focusing lens 53 to reduce the size of the light spot 633. The stepping motor 62 drives the chopper modulation sheet 64 to rotate to perform chopper modulation on the light beam. After the modulated light beam is received by the dual-channel infrared detector 631, it is converted into an electrical signal. The data acquisition terminal 7 acquires the temperature and pressure information transmitted by the temperature and pressure sensor 44 and the electrical signal information containing the gas concentration information transmitted by the dual-channel infrared detector 631.

[0035] For multi-component gas sampling, by arranging the first gas analysis component 1 and the second gas analysis component 2 with the same structure and replacing the dual-channel infrared detectors 631 with different wavelength bands, the simultaneous detection of multi-component gases can be achieved.

[0036] Any technical solution using the technical solution of the present invention or designed by those skilled in the art inspired by the technical solution of the present invention and achieving the above technical effects shall fall within the protection scope of the present invention.

Claims

1. A small multi-gas detection system based on incoherent broadband cavity enhancement technology, characterized by: The invention comprises a first gas analysis component (1), a second gas analysis component (2), a detection component (6) and a data acquisition terminal (7), wherein the first gas analysis component (1) and the second gas analysis component (2) have the same structure, and the first gas analysis component (1) and the second gas analysis component (2) are arranged in parallel; the detection component (6) is installed at the ends of the first gas analysis component (1) and the second gas analysis component (2); and the data acquisition terminal (7) is arranged on a side of the detection component (6) away from the first gas analysis component (1); The first gas analysis component (1) comprises a radiation source component (3), an incoherent broadband component (4) and a light source focusing component (5); the incoherent broadband component (4) is mounted on a side of the radiation source component (3) close to the detection component (6); the light source focusing component (5) is mounted on a side of the incoherent broadband component (4) close to the detection component (6); The radiation source assembly (3) comprises a light source collimating cavity (31), an infrared radiation source (32), a radiation source window sheet (33) and an air inlet (34); the infrared radiation source (32) is mounted on a side of the light source collimating cavity (31) facing away from the detection assembly (6), and a distal end of the infrared radiation source (32) is located inside the light source collimating cavity (31); the radiation source window sheet (33) is mounted on a side of the infrared radiation source (32) close to the detection assembly (6); and the air inlet (34) is disposed on an upper side of the light source collimating cavity (31); The incoherent broadband component (4) comprises an incoherent broadband cavity (41), a plano-convex collimating lens (42), a first plano-concave reflecting mirror (43), a temperature and pressure sensor (44), a second plano-concave reflecting mirror (45) and a first-order converging lens (46); the incoherent broadband cavity (41) is mounted on a side of the light source collimating cavity (31) close to the detection component (6); the temperature and pressure sensor (44) is mounted on the upper side of the incoherent broadband cavity (41), and the detection probe of the temperature and pressure sensor (44) is located at the bottom of the incoherent broadband cavity. (41); the plano-convex collimating lens (42) is installed on a side of the incoherent broadband cavity (41) close to the light source collimating cavity (31); the first plano-concave reflecting mirror (43) is installed on a side of the plano-convex collimating lens (42) away from the light source collimating cavity (31); the first-stage concave focusing lens (46) is installed on a side of the incoherent broadband cavity (41) away from the light source collimating cavity (31); the second plano-concave reflecting mirror (45) is installed on a side of the first-stage converging lens (46) close to the light source collimating cavity (31); The light source focusing assembly (5) comprises a light source focusing cavity (51), an air outlet (52) and a secondary converging lens (53); the light source focusing cavity (51) is installed on a side of the incoherent broadband cavity (41) away from the light source collimating cavity (31); the air outlet (52) is provided on the upper side of the light source focusing cavity (51); and the secondary converging lens (53) is installed inside the light source focusing cavity (51) on a side away from the incoherent broadband cavity (41); The detection assembly (6) comprises a signal detection cavity (61), a stepper motor (62), a dual-channel infrared detection assembly (63) and a chopper modulation plate (64); the signal detection cavity (61) is located on a side of the light source focusing cavity (51) away from the light source focusing cavity (51); the stepper motor (62) is installed at a middle position of the signal detection cavity (61) on a side away from the light source focusing cavity (51); the chopper modulation plate (64) is installed on an output shaft of the stepper motor (62); two dual-channel infrared detection assemblies (63) are used, and the dual-channel infrared detection assemblies (63) are installed inside the signal detection cavity (61), and the dual-channel infrared detection assemblies (63) are located on a side of the chopper modulation plate (64) away from the light source focusing cavity (51); The dual-channel infrared detection assembly (63) comprises a dual-channel infrared detector (631), a gas measurement channel (632), a light spot (633) and a gas reference channel (634). Two dual-channel infrared detectors (631) are used, and the dual-channel infrared detectors (631) are installed inside the signal detection cavity (61). The dual-channel infrared detector (631) is located on the side of the chopper modulation plate (64) away from the light source focusing cavity (51). The dual-channel infrared detector (631) is connected to the mains via a wire, and the dual-channel infrared detector (631) is used to receive the modulated light beam and convert it into an electrical signal. The dual-channel infrared detector (631) is designed with a polarization axis that is consistent with the plano-convex collimating lens (42) and the first plano-concave reflector (43). The gas measurement channel (632), the light spot (633) and the gas reference channel (634) are located on the side of the dual-channel infrared detector (631) close to the light source focusing cavity (51). The connection between the incoherent broadband cavity (41) and the light source collimating cavity (31) is provided with evenly arranged vent holes, and the evenly arranged vent holes enable the sampled gas to quickly flush the incoherent broadband cavity (41); the temperature and pressure sensor (44) is connected to the mains via a wire; The connection between the light source focusing cavity (51) and the incoherent broadband cavity (41) is provided with evenly arranged vent holes; the gas outlet (52) is provided with a one-way valve for preventing gas from flowing back from the gas outlet (52) into the interior of the light source focusing cavity (51); the secondary converging lens (53), the infrared radiation source (32), the radiation source window (33), the plano-convex collimating lens (42), the first plano-concave reflector (43), the second plano-concave reflector (45) and the primary converging lens (46) adopt a coaxial optical path design; The connection between the signal detection cavity (61) and the light source focusing cavity (51) is provided with evenly arranged ventilation holes; the stepping motor (62) is connected to the mains via a wire; and the chopper modulation plate (64) is driven by the stepping motor (62) to rotate, thereby chopping and modulating the light beam.

2. The small multi-gas detection system based on incoherent broadband cavity enhancement technology as claimed in claim 1, characterized in that: The data acquisition end (7) is connected to the mains, the temperature and pressure sensor (44) and the dual-channel infrared detector (631) respectively through wires, and the data acquisition end (7) collects temperature and pressure information transmitted by the temperature and pressure sensor (44) and electrical signal information containing gas concentration information transmitted by the dual-channel infrared detector (631).

3. The small multi-gas detection system based on incoherent broadband cavity enhancement technology as claimed in claim 1, characterized in that: A sealing ring is provided at the connection between the light source collimating cavity (31) and the infrared radiation source (32); the infrared radiation source (32) adopts one of an LED light source, an SC light source, and a halogen tungsten lamp light source; the radiation source window sheet (33) is used to reduce the influence of the sampling gas entering from the air inlet (34) on the light source of the infrared radiation source (32); the air inlet (34) is connected to an external pump through a pipeline.

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