Small multi-gas detection system based on incoherent broadband cavity enhancement technology

Abstract

The invention provides a small-sized multi-gas detection system based on an incoherent broadband cavity enhancement technology, and relates to the technical field of gas detection, the small-sized multi-gas detection system comprises a first gas analysis assembly, a second gas analysis assembly and a detection assembly, the first gas analysis assembly and the second gas analysis assembly adopt the same structure, the first gas analysis assembly and the second gas analysis assembly are arranged in parallel; according to the invention, the radiation source assembly, the incoherent broadband assembly, the light source focusing assembly, the detection assembly and the like are integrated together, so that gas signal detection can be completed in one instrument; compared with a traditional detection mode that an absorbed light path needs to be introduced into a spectrum through an optical fiber or a turn-back mirror, the size and the integration degree of an instrument are greatly reduced, and miniaturization of an incoherent broadband cavity enhanced absorption spectrum technology serving as a high-sensitivity optical detector is achieved. The advantages of high sensitivity, small size, short response time and the like are met, and the complex and changeable gas detection requirements are met.

Description

Technical Field

[0001] The invention belongs to the technical field of gas detection, and in particular relates to a small multi-gas detection system based on incoherent broadband cavity enhancement technology. Background Art

[0002] With the rapid development of environmental science, industrial safety, aerospace and other fields, the requirements for gas detection technology are getting higher and higher. Although traditional gas detection methods, such as electrochemical method and chromatography, can detect specific gases to a certain extent, they often have limitations such as low sensitivity, large size, and long response time, making it difficult to adapt to complex and changing detection needs. As a highly sensitive optical detection method, incoherent broadband cavity enhanced absorption spectroscopy has received extensive attention in recent years. By constructing an optical resonant cavity composed of high-reflectivity lenses, this technology can effectively increase the absorption optical path, thereby improving the detection sensitivity of the measured gas. At the same time, due to the use of incoherent broadband light sources, this technology can achieve simultaneous detection of multiple gases, making gas analysis in complex environments possible. For the current incoherent broadband cavity enhanced absorption spectroscopy technology, it can be divided into ultraviolet band region and infrared band region according to the different detection gases. In the ultraviolet band region, LED is often used as the light source, and the optical resonant cavity is used to detect the gas. After the absorption path grows, the gas information is introduced into the spectrometer for analysis to obtain the absorption information of the corresponding gas; in the infrared band, halogen tungsten lamps, quantum cascade lasers, and SC light sources are often used as infrared light sources. After the absorption path grows through the optical resonant cavity, the gas information is introduced into the Fourier transform spectrometer for analysis to obtain the corresponding gas absorption information; when existing instruments based on the incoherent cavity enhancement principle obtain gas concentration absorption information, they often need to solve the absorbed optical information through spectral analysis. The required calculation amount is huge, and many instruments are used in the processing process. The instruments used are large in size, making it difficult to be effectively applied in actual measurement environments.

[0003] Therefore, it is very necessary to invent a small multi-gas detection system based on incoherent broadband cavity enhancement technology. Summary of the invention

[0004] In order 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 technology 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 terminal, wherein the first gas analysis component and the second gas analysis component adopt the same structure, and the first gas analysis component and the second gas analysis component 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 terminal is arranged on the side of the detection component away from the first gas analysis component; the data acquisition terminal is connected to the mains, the temperature and pressure sensor and the dual-channel infrared detector through wires, respectively, and the data acquisition terminal collects the temperature and pressure information transmitted by the temperature and pressure sensor and the electrical signal information containing the gas concentration information transmitted by the dual-channel infrared detector; by arranging the first gas analysis component and the second gas analysis component of the same structure and replacing the dual-channel infrared detectors of different bands, the simultaneous detection of multi-component gases can be achieved.

[0005] The first gas analysis component includes a radiation source component, an incoherent broadband component and a light source focusing component, wherein 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; the radiation source component, the incoherent broadband component, the light source focusing component and the detection component are integrated together, and the gas signal detection can be completed in one instrument. Compared with the traditional detection form that requires the absorbed light path to be introduced into the spectrum through an optical fiber or a reflecting mirror, the size and integration level of the instrument are greatly reduced, and the incoherent broadband cavity enhanced absorption spectroscopy technology is realized as a miniaturized high-sensitivity optical detector, which meets the advantages of high sensitivity, small size, short response time, etc., and adapts to complex and changeable gas detection needs.

[0006] The radiation source assembly includes a light source collimating cavity, an infrared radiation source, a radiation source window and an air inlet, wherein the infrared radiation source is installed on a side of the light source collimating cavity away from the detection assembly, and the end of the infrared radiation source is located inside the light source collimating cavity; the radiation source window is installed on a side of the infrared radiation source close to the detection assembly; the air inlet is opened on the upper side of the light source collimating cavity; a sealing ring is provided at the connection between the light source collimating cavity and the infrared radiation source; the infrared radiation source adopts one of an LED light source, an SC light source and a halogen tungsten lamp light source; the radiation source window 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.

[0007] 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-level converging lens, wherein the incoherent broadband cavity is installed on the 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 the side 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 away from the light source collimating cavity; the first-level converging lens is installed inside the incoherent broadband cavity on the side away from the light source collimating cavity; the second plano-concave reflector is installed on the side of the first-level converging lens close to the light source collimating cavity; the connection between the incoherent broadband cavity and the light source collimating cavity is provided with evenly arranged air holes, and the evenly arranged air holes enable the sampling gas to quickly flush the incoherent broadband cavity; the temperature and pressure sensor is connected to the mains via a wire.

[0008] Preferably, the light source focusing assembly includes a light source focusing cavity, an air outlet and a secondary converging lens, wherein the light source focusing cavity is installed on the side of the incoherent broadband cavity away from the light source collimating cavity; the air outlet is opened on the upper side of the light source focusing cavity; the secondary converging lens is installed on the side of the light source focusing cavity away from the incoherent broadband cavity; the connection between the light source focusing cavity and the incoherent broadband cavity is provided with evenly arranged air vents; the air outlet is provided with a one-way valve to prevent gas from flowing back from the air outlet into the interior of the light source focusing cavity; the secondary converging lens, infrared radiation source, radiation source window, plano-convex collimating lens, first plano-concave reflector, second plano-concave reflector and primary converging lens adopt a coaxial optical path design.

[0009] Preferably, the detection component includes a signal detection cavity, a stepper motor, a dual-channel infrared detection component and a chopper modulator, wherein the signal detection cavity is located on a side of the light source focusing cavity away from the light source focusing cavity; the stepper motor is installed in the middle position of the signal detection cavity away from the light source focusing cavity; the chopper modulator is installed on the output shaft of the stepper motor; the dual-channel infrared detection components are two, and the dual-channel infrared detection components are installed in the signal detection cavity, and the dual-channel infrared detection components are located on the side of the chopper modulator away from the light source focusing cavity; the connection between the signal detection cavity and the light source focusing cavity is provided with evenly arranged vents; the stepper motor is connected to the mains through a wire; the chopper modulator is driven by the stepper motor to rotate so as to chop and modulate the light beam; the entire detection system adopts a fully enclosed detection cavity and a unique air path arrangement, compared with the traditional method of placing the air inlet and outlet ends on an incoherent broadband cavity, it effectively utilizes the absorption optical path of the light source collimating cavity and the light source focusing cavity, while eliminating the airflow dead angle of the detection system, speeding up the response time of the detection system, and making the measurement result more accurate.

[0010] 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 detector is located on the side of the chopper modulator away from the light source focusing cavity, wherein the dual-channel infrared detector is connected to the mains through a wire, and the dual-channel infrared detector is used to convert the modulated light beam into an electrical signal after receiving, wherein the dual-channel infrared detector adopts a polarization axis design with a plano-convex collimating lens and a first plano-concave reflector; the gas measurement channel, light spot and 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 detector adopts a polarization axis design, and compared with the general coaxial design, the eccentric design enables the gas absorption channel to obtain a higher signal value, thereby being more sensitive to changes in gas concentration, thereby improving the sensitivity of the instrument while improving the detection accuracy.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. In the present invention, the radiation source component, the incoherent broadband component, the light source focusing component and the detection component are integrated together, and the gas signal detection can be completed in one instrument. Compared with the traditional detection form that requires the absorbed light path to be introduced into the spectrum through an optical fiber or a folding mirror, the volume and integration of the instrument are greatly reduced, and the incoherent broadband cavity enhanced absorption spectroscopy technology is miniaturized as a high-sensitivity optical detector, which meets the advantages of high sensitivity, small size, short response time, etc., and adapts to the complex and changeable gas detection needs; 2. In the present invention, a unique design for improving the air intake of the optical cavity is to arrange air holes connected to the optical cavity evenly distributed around the cavity mirror. This arrangement enables the sample gas to quickly purge the optical cavity air chamber, thereby realizing the rapid replacement of the measured gas in the air chamber. Compared with the traditional method of placing the inlet and outlet ends on an incoherent broadband cavity, the traditional side air intake is changed to end face air intake, which improves the eddy current distribution caused by the side air intake, eliminates the concentration exchange dead zone, and increases the concentration balance response speed by 8.75 times, which is crucial to improving the spatial resolution of the instrument. This also enables the instrument to more effectively respond to gas concentration measurements during rapid movement, speeds up the response time of the detection system, and makes the measurement results more accurate. 3. In the present invention, the dual-channel infrared detector adopts a polarization axis design. Compared with the general coaxial design, the eccentric design enables the gas absorption channel to obtain a higher signal value, thereby being more sensitive to changes in gas concentration, thereby improving the detection accuracy and the sensitivity of the instrument; 4. In the present invention, by arranging the first gas analysis component and the second gas analysis component of the same structure and replacing the dual-channel infrared detectors of different bands, simultaneous detection of multi-component gases can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the present invention.

[0013] Figure 2 It is a schematic diagram of the internal structure of the present invention.

[0014] Figure 3 It is a structural schematic diagram of the dual-channel infrared detection component of the present invention.

[0015] In the figure: 1. First gas analysis component; 2. Second gas analysis component; 3. Radiation source component; 31. Light source collimating cavity; 32. Infrared radiation source; 33. Radiation source window; 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. Primary converging lens; 5. Light source focusing component; 51. Light source focusing cavity; 52. Air outlet; 53. Secondary converging 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 modulator; 7. Data acquisition terminal. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with the accompanying drawings: Example: As attached Figure 1 To Attachment Figure 3 Shown 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.

[0017] 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; 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.

[0018] 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-level converging lens 46. The incoherent broadband cavity 41 is installed on a 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 a side of the incoherent broadband cavity 41 close to the light source collimating cavity 31. side; the first plano-concave reflector 43 is installed on the side of the plano-convex collimating lens 42 away from the light source collimating cavity 31; the first-level converging lens 46 is installed inside the incoherent broadband cavity 41 on the side away from the light source collimating cavity 31; the second plano-concave reflector 45 is installed on the side of the first-level converging lens 46 close to the light source collimating cavity 31; the connection between the incoherent broadband cavity 41 and the light source collimating cavity 31 is provided with evenly arranged air holes, and the evenly arranged air 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.

[0019] In this embodiment, the light source focusing assembly 5 includes 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 the side of the incoherent broadband cavity 41 away from the light source collimating cavity 31; the air outlet 52 is opened on the upper side of the light source focusing cavity 51; the secondary converging lens 53 is installed on the side of the light source focusing cavity 51 away from the incoherent broadband cavity 41; the connection between the light source focusing cavity 51 and the incoherent broadband cavity 41 is provided with evenly arranged air vents; the air outlet 52 is provided with a one-way valve to prevent the gas outlet 52 from flowing back 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.

[0020] In this embodiment, the detection component 6 includes a signal detection cavity 61, a stepper motor 62, a dual-channel infrared detection component 63 and a chopper modulator 64. The signal detection cavity 61 is on the side of the light source focusing cavity 51 away from the light source focusing cavity 51; the stepper motor 62 is installed in the middle position of the signal detection cavity 61 away from the light source focusing cavity 51; the chopper modulator 64 is installed on the output shaft of the stepper motor 62; two dual-channel infrared detection components 63 are used, and the dual-channel infrared detection components 63 are installed in the signal detection cavity 61, and the dual-channel infrared detection components 63 are located on the side of the chopper modulator 64 away from the light source focusing cavity 51; the connection between the signal detection cavity 61 and the light source focusing cavity 51 is provided with evenly arranged ventilation holes; the stepper motor 62 is connected to the mains through a wire; the chopper modulator 64 is driven by the stepper motor 62 to rotate so as to chop and modulate the light beam.

[0021] 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 detector 631 is located on the side of the chopper modulator 64 away from the light source focusing cavity 51, wherein the dual-channel infrared detector 631 is connected to the mains through a wire, and the dual-channel infrared detector 631 is used to convert the modulated light beam into an electrical signal after receiving it, wherein the dual-channel infrared detector 631 is designed with a polarization axis of a plano-convex collimating lens 42 and a 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.

[0022] How it works In the present invention, during the sampling process, the gas to be tested is extracted by an external pump and enters the light source collimating cavity 31 through the air inlet 34. The gas entering the light source collimating cavity 31 enters the incoherent broadband cavity 41 through the uniformly distributed small holes connecting the light source collimating 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 air outlet 52. In the gas measurement process, the infrared radiation emitted by the infrared radiation source 32 passes through the radiation source window 33 and enters the light source collimating cavity 31, and 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 time a part of the light passes through the second plano-concave reflector 45, passes through the primary converging lens 46 and the secondary converging lens 53, and the light source is reduced by the primary converging lens 46 and the secondary converging lens 53 to reduce the size of the light spot 633. The stepper motor 62 drives the chopper modulator 64 to rotate to realize chopper modulation of the light beam. The modulated light beam is received by the dual-channel infrared detector 631 and converted into an electrical signal. 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 the gas concentration information transmitted by the dual-channel infrared detector 631.

[0023] Multi-component gas sampling can realize simultaneous detection of multi-component gases by arranging a first gas analysis component 1 and a second gas analysis component 2 of the same structure and replacing a dual-channel infrared detector 631 of different bands.

[0024] Utilizing the technical solution of the present invention, or those skilled in the art designing similar technical solutions inspired by the technical solution of the present invention to achieve the above-mentioned technical effects, all 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) 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 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 opened on the upper side of the light source collimating cavity (31).

2. The small multi-gas detection system based on incoherent broadband cavity enhancement technology as claimed in claim 1, characterized in that: 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-level concave 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-level converging lens (46) is installed on a side of the incoherent broadband cavity (41) away from the light source collimating cavity (31); and the second plano-concave reflecting mirror (45) is installed on a side of the first-level converging lens (46) close to the light source collimating cavity (31).

3. The small multi-gas detection system based on incoherent broadband cavity enhancement technology as claimed in claim 1, characterized in that: 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 opened 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).

4. The small multi-gas detection system based on incoherent broadband cavity enhancement technology as claimed in claim 1, characterized in that: 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).

5. The small multi-gas detection system based on incoherent broadband cavity enhancement technology as claimed in claim 4, characterized in that: 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), wherein 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, wherein the dual-channel infrared detector (631) is designed with a polarization axis corresponding to 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).

6. 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).

7. 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.

8. The small multi-gas detection system based on incoherent broadband cavity enhancement technology as claimed in claim 2, characterized in that: 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.

9. The small multi-gas detection system based on incoherent broadband cavity enhancement technology as claimed in claim 3, characterized in that: 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 sheet (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.

10. The small multi-gas detection system based on incoherent broadband cavity enhancement technology as claimed in claim 4, characterized in that: 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.

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