WO2019228407A1

WO2019228407A1 - Annular multi-point reflective photoelectric gas sensor probe

Info

Publication number: WO2019228407A1
Application number: PCT/CN2019/089037
Authority: WO
Inventors: 刘统玉; 宁雅农; 李艳芳; 金光贤; 张婷婷; 宁凯文
Original assignee: 山东省科学院激光研究所
Priority date: 2018-05-30
Filing date: 2019-05-29
Publication date: 2019-12-05
Also published as: CN108931504A; CN108931504B

Abstract

An annular multi-point reflective photoelectric gas sensor probe, comprising an annular multi-point light reflection ring. The annular multi-point light reflection ring is a hollow cylinder structure, and upper and lower side surfaces of the hollow cylinder structure are each provided with a cover plate. A cavity formed by the hollow cylinder structure and the cover plates thereof is a gas absorption tank that accommodates a gas to be tested, wherein the center of one of the cover plates is provided with a solid cylinder that reduces the total volume of the gas absorption tank. The hollow cylinder structure is provided thereon with a light beam entrance and exit opening, and a parallel light transceiving module is fixedly disposed at the opening. The parallel light transceiving module is used to generate parallel light and transmit the processed parallel light to the gas absorption tank for outputting after a plurality of reflections. The present design for annular multi-point reflection not only reduces the volume of an absorption tank of a sensor probe but also increases the optical path, while simultaneously also greatly improving the stability and reliability of the optical path, and lessens production and processing costs while reducing the difficulty of debugging.

Description

Multi-point reflection type photoelectric gas sensor probe

Technical field

The invention relates to the technical field of laser spectrum gas sensors, in particular to a ring multi-point reflection type photoelectric gas sensor probe.

Background technique

In recent years, with people's increasing requirements for environmental testing and production safety control, many new gas detection technologies and equipment have continuously entered the market. As optoelectronic components are widely used in the optical fiber communication industry, their production costs continue to decline, and their product types continue to increase. As a result, the cost of optoelectronic technology equipment that uses the principle of infrared laser spectral absorption to measure gas components and concentrations has been reduced, the volume has become smaller, and the performance has improved And become more practical.

The increasingly mature tunable diode laser absorption spectroscopy (TDLAS) technology is a gas detection technology with high sensitivity, high selectivity and fast detection.It uses the tunable, narrow linewidth characteristics of semiconductor lasers to detect the absorption of gases in the spectrum. The light absorption at the peak enables rapid detection of the gas concentration and avoids interference of other gases on the measurement. This new type of laser spectrum gas sensor not only has excellent characteristics such as large measurement concentration range and high measurement accuracy, but also has a long calibration interval, which is convenient to use and easy to popularize. These characteristics make the laser spectrum gas sensor can be widely applied to different production processes and safety precautions.

Optical spectral absorption gas sensors include infrared spectral absorption type and infrared laser spectral absorption type. The former uses an infrared broad-spectrum light source as a measurement light source, while the latter uses an infrared laser as its measurement light source. Because different gases have different spectral characteristic absorption peaks in the infrared spectral region, when the measured gas passes through the infrared beam or infrared laser beam, the gas molecules interact with the incident beam, so that the intensity of the emitted light is affected by the characteristic spectral absorption peak. Test gas modulation. Because the amplitude of the light intensity modulation is directly proportional to the concentration of the measured gas, the concentration of the measured gas can be detected by detecting and analyzing the change in light intensity at the infrared absorption peak.

Compared with infrared spectral absorption type gas sensors, infrared laser spectral absorption type gas sensors have higher resistance to gas cross interference. This is because the laser's spectral line is narrow and coincides with the absorption peak line of the gas. Therefore, the infrared laser spectral gas sensor is only sensitive to the locked gas concentration, which makes it have good resistance to gas cross interference. Combined with modern digital electronic processing technology, these sensors can realize continuous testing and automatic operation of the measured gas; and have the characteristics of automatic calibration, high measurement accuracy and fast response time. This type of sensor can be used in many industrial production processes, such as detection and alarm in petrochemical, fermentation industry, pharmaceutical production, mining, semiconductor industry and other industrial and mining production, for example, combustible carbon such as oxygen, carbon monoxide, carbon dioxide, chlorine, methane, acetylene, etc. Hydrogen compounds and the like are the main detection gases. The detection of phosphorus, arsenic, and silane is required in the semiconductor industry. With the widespread application and mass production of such sensors, these sensors can also be used for security detection and alarm in public and home environments. It is mainly used in homes to detect gas, natural gas and liquefied gas leaks and safety alarms.

The gas chamber of a general gas sensor or the gas absorption cell mostly uses the space between the laser source and the detector as a measurement gas chamber. In the case that the volume of the sensor is limited, in order to increase the measurement optical path length, the measurement air chamber is usually implemented by using multiple mirrors or reflectors to reflect the light path in the air chamber multiple times. Such as White reflection cavity, Herriott reflection cavity and CEAS reflection cavity and other programs. A typical White structure multi-reflection cell is a confocal cavity composed of three spherical mirrors. The incident beam is focused on spherical mirror A. After B or C reflection and focusing, the focus still falls on A. A traditional Herriott pool is formed by placing two spherical mirrors (which have the same focal length) face to face to form a multi-reflection cavity. At least one of the two mirrors contains a central hole. Light enters and exits through the holes in the mirror and is reflected multiple times in this pool before returning to its entry point. The reflection cavity of Cavity Enhanced Absorption Spectroscopy (CEAS) is a stable optical resonant cavity composed of about 99.7% of a flat concave mirror as an absorption cell.

Because the above reflection cavity uses multiple optical elements to form the absorption cell, the optical structure of the absorption cell becomes complicated. If the position of any one component is changed relative to the position of other components, the optical path will change accordingly, thereby affecting the measurement accuracy. At the same time, due to the use of many optical components, it is difficult to adjust the optical path, and it also increases the complexity of the production process and reduces the yield, which is not conducive to large-scale production. Therefore, reducing the possibility of changes in the relative position of each element, reducing the difficulty of adjusting the optical path, and improving the stability of the optical path system are urgent problems to be solved in the technical field.

In practical applications, another important factor affecting measurement is the response time of the measured gas concentration. Since the above reflection cavities all adopt a three-dimensional three-dimensional structure, the volume of the gas absorption cell is relatively large, and the time for gas to fill and disperse out of the absorption cell is relatively long, resulting in a long response time for measurement. This factor will limit some practical online inspection applications. Therefore, reducing the volume of the absorption cell, thereby reducing the corresponding measurement time, is also a problem to be solved urgently in the technical field.

Summary of the Invention

In order to solve the shortcomings of the prior art, the present invention provides a ring-shaped multi-point reflection type photoelectric gas sensor probe, which uses a single reflective element to overcome the defects of multiple separate elements in the prior art and makes the optical path very stable; The three-dimensional stereo optical path is changed into a two-dimensional planar optical path, thereby reducing the volume of the absorption cell, reducing the measurement response time, and solving the urgent problems in the technical field.

An annular multi-point reflection type photoelectric gas sensor probe includes an annular multi-point light reflection ring. The annular multi-point light reflection ring is a hollow cylindrical structure, and a cover plate is provided on the upper and lower sides of the hollow cylindrical structure. The cavity formed by the hollow cylinder structure and its cover plate is a gas absorption cell that contains the gas to be measured, and a center of one of the cover plates is provided with a cylinder that reduces the total volume of the gas absorption cell;

The hollow cylinder structure is provided with a beam entrance and exit opening, and a parallel light transceiver module is fixedly arranged at the opening. The parallel light transceiver module is used to generate parallel light and transmit the parallel light to the gas absorption cell for multiple reflections. Output.

In a further preferred technical solution, the cover plate is an upper cover plate and a lower cover plate, and one or both cover plates are provided with a plurality of vent holes, and the gas to be measured diffuses into the gas absorption cell from the vent holes. .

In a further preferred technical solution, the inner wall of the cover plate is coated with a black coating for reducing reflected light.

In a further preferred technical solution, a pressure sensor for measuring a pressure in the gas absorption tank is installed in one of the plurality of ventilation holes;

Or a temperature sensor is installed in a vent hole for measuring the temperature in the gas absorption cell.

In a further preferred technical solution, a material of the ring-shaped multi-point light reflection ring is metal, plastic or synthetic material, and the ring-shaped multi-point light reflection ring is formed by machining or precision injection molding.

In a further preferred technical solution, the inner wall of the ring-shaped multi-point light reflection ring is optically polished by a mirror surface and plated with a reflective film to form a circular-arc mirror surface, or the inner wall of the ring-shaped multi-point light reflection ring is made of a reflective material to make an arc. Mirror surface.

In a further preferred technical solution, the parallel light transmitting and receiving module includes: a parallel laser source, the parallel laser source is connected to a first light intensity detector, and a light intensity change of the parallel laser source is measured by the first light intensity detector And modulated, the second light intensity detector is connected to the reference air chamber, and a beam splitter is arranged between the first light intensity detector and the second light intensity detector;

The parallel beam emitted by the parallel laser source is divided into a reflected beam and a transmitted beam by a beam splitter. The reflected beam is received by the second light intensity detector to form a reference signal during measurement. The transmitted beam is incident on the gas absorption cell for multiple reflections. Light intensity detector output.

In a further preferred technical solution, the parallel laser source and the first light intensity detector are an integrated structure or a separate structure, and the second light intensity detector and the reference air chamber are an integrated structure or a separate structure.

In a further preferred technical solution, a lens for focusing parallel light on a detection sensitive surface is disposed in front of the third light intensity detector.

In a further preferred technical solution, the beam splitter can adjust a ratio of a light intensity of a reflected light beam and a light intensity of the transmitted light beam.

In a further preferred technical solution, when the second light intensity detector is integrated with a reference gas chamber, a packaging cap of the second light intensity detector is filled with a high concentration of a gas to be measured, and the second light intensity detection The incident laser light received by the device is modulated by a high-concentration gas to be measured, and its output signal carries information about the absorption spectrum of the gas to be measured.

In a further preferred technical solution, the transmitted light beam enters the ring-shaped multi-point light reflection ring from the light beam entrance and exit opening, and the transmitted light beam enters the ring-shaped multi-point light reflection ring from the beam entrance and exit opening at a set incident angle and is formed by The circular multi-point light reflection ring has multiple reflections on the circular mirror surface, and the incident angle refers to the angle between the center line of the light reflection ring formed by the incident light beam and the circular reflection mirror surface.

In a further preferred technical solution, the number of reflections of the incident light beam in the light reflection ring is determined by the radius of the light reflection ring and the incident angle, and the number of multi-point reflections determines the measurement of the light beam in the light reflection ring. Total optical path length.

In a further preferred technical solution, the laser light source is connected to its driving circuit, and the first light intensity detector, the second light intensity detector, and the third light intensity detector are all connected to respective signal processing circuits.

In a further preferred technical solution, the above-mentioned annular multi-point reflection type photoelectric gas sensor probe is arranged in a housing with a metal filter.

A further preferred technical solution is a photoelectric gas detection device including the above-mentioned annular multi-point reflection type photoelectric gas sensor probe.

Compared with the prior art, the beneficial effects of the present invention are:

The gas absorption cell of the photoelectric gas sensor probe of the present invention uses a two-dimensional annular multi-point light reflection ring of a single optical element, which reduces the possibility of changes in the relative position of each element and improves the stability of the optical path system.

The invention increases the total detection optical path in the absorption cell through the multiple beam reflection of the two-dimensional light reflection ring, which is beneficial to improve the detection signal-to-noise ratio and measurement accuracy; the sensor probe is reduced by the two-dimensional ring multi-point light reflection ring The volume, thus reducing the response time of the measurement.

The present invention reduces the difficulty of adjusting the optical path by adopting the design of the parallel optical transceiver module; the overall invention design reduces the complexity of the production process and improves the production yield, which is beneficial to large-scale production.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings that form a part of the present application are used to provide further understanding of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application.

FIG. 1 is a schematic structural diagram of a multi-point reflection photoelectric gas sensor probe provided by the embodiment of the invention; FIG.

FIG. 2 is a first implementation of a light path structure in a multi-point reflection photoelectric gas sensor probe according to the embodiment of the invention (short detection optical path scheme); FIG.

3 is a second implementation manner of the optical path structure in the photoelectric gas sensor probe of the embodiment of the invention (a long detection optical path scheme);

4 is a top cover of a photoelectric gas sensor probe according to an embodiment of the invention;

5 is a lower cover plate of a ring-shaped photoelectric gas sensor probe according to the embodiment of the invention;

6 is a schematic structural diagram of a parallel optical transceiver mode according to the embodiment of the invention;

FIG. 7 is a circular photoelectric gas sensor probe according to the embodiment of the invention, which is arranged in a housing with a metal filter;

In the figure, 1, the first light intensity detector, 2, the beam splitter, 3, the second light intensity detector, 4, the third light intensity detector, 5, the connector that controls the angle of incidence, and 6, the metal filter.

Detailed ways

It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanation of the present application. Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It should be noted that the terminology used herein is only for describing specific embodiments and is not intended to limit the exemplary embodiments according to the present application. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise, and it should also be understood that when the terms "including" and / or "including" are used in this specification, they indicate There are features, steps, operations, devices, components, and / or combinations thereof.

The technical scheme and advantages of the annular photoelectric gas sensor probe of the invention will be further described in detail below with reference to FIGS. 1 to 7 and embodiments. What is described here is only used to explain the design of the ring type of the present invention, and is not intended to limit the design of the present invention.

It should be emphasized that the following describes the specific structure and characteristics of the photoelectric gas sensor probe by way of example, which should not constitute any limitation to the present invention. At the same time, any one of the technical features mentioned below (including implicit or public), and any one of the technical features directly displayed or implied in Figures 1 to 7, can be included in these technical features (or their equivalents) Any combination or deletion is continued between them), so as to form many other embodiments that may not be directly or indirectly mentioned in the present invention.

Please refer to the basic structure of the embodiment of the annular photoelectric gas sensor probe shown in FIGS. 1 to 7.

A typical implementation example of the present application. In this embodiment, the ring-shaped photoelectric gas sensor probe includes: a ring-shaped photoelectric gas sensor probe upper cover (see FIG. 4), and a ring-shaped photoelectric gas sensor probe lower cover (see FIG. 5). ), The light reflection ring of the ring-shaped photoelectric gas sensor probe (see Figure 1), the reflected light path in the ring-shaped photoelectric gas sensor probe (see Figures 2 and 3), and the parallel optical transceiver mode (see Figure 6). The annular photoelectric gas sensor probe is placed in the sensor housing (see Figure 7) to form a sensor that can perform gas detection.

Based on the working principle, the annular photoelectric gas sensor probe is explained as follows: The annular multi-point reflective photoelectric gas sensor probe includes a circular light reflection ring with an inner wall as a reflecting mirror surface (see Fig. 1): the inside of the light reflection ring of the photoelectric gas sensor The cavity forms the gas absorption cell of the gas sensor, and its internal volume is used to contain the gas to be measured; its reflective mirror surface will reflect the parallel laser beam incident at a specific angle multiple times, forming dense multiple reflections in the light reflection ring Light (see Figures 2 and 3). The material for making the light reflection ring may be a solid material such as metal, plastic, and synthetic material. The inner wall of the light reflection ring is optically polished on a mirror surface and plated with a reflection film to form a working surface of the light reflection ring. The side of the gas absorption cell is provided with a plurality of ventilation holes, and the measured gas will diffuse into the absorption cell through the plurality of ventilation holes on the side of the through hole. A special optical transceiver module is installed at the entrance and exit of the light reflection ring. The optical transceiver module includes at least a tunable parallel laser source with a light intensity detector, a beam splitter, a light detector with a reference gas chamber, and a conventional light detector. The light intensity change of the tunable parallel laser source can be measured by a built-in light intensity detector, and the parallel beam emitted by the parallel laser source is divided into a reflected beam and a transmitted beam through the beam splitter; The light beam is measured and received by the photodetector with a reference gas chamber; the transmitted light beam reaches the light entrance and exit of the light reflection ring and enters the light reflection ring, and then reaches the reflection working surface of the light reflection ring; the reflected light passes through the reflection mirror Multiple reflections from the working surface are finally emitted from the beam entrance and exit and measured and received by the light detector.

These components are described in detail below.

The material of the light reflection ring can be metal, plastic, synthetic material, etc. The light reflection ring can be formed by mechanical processing or precision injection molding. The inner wall of the light reflection ring is optically polished by a mirror surface, and a reflective film is plated to form a working surface of the light reflection ring. The light reflection ring has a hollow cylindrical structure.

The upper cover of the ring-shaped photoelectric gas sensor probe is set on the top of the light reflection ring; the lower cover of the ring-shaped photoelectric gas sensor probe is set on the bottom of the light reflection ring. The upper and lower cover plates are provided with gas through holes, as shown in FIGS. 4 and 5. The gas absorption cell is composed of the inner cavity of the light reflection ring and the cavity between the upper and lower cover plates.

In this embodiment, the upper and lower covers are square covers.

In the ring-shaped photoelectric gas sensor probe, as shown in FIG. 6, the parallel light transmitting and receiving mode is a parallel laser source with a modifiable light intensity with a built-in light intensity detector (the built-in light intensity detector is the first light intensity Detector 1), a beam splitter 2, a light intensity detector with a reference gas chamber (the light intensity detector here is the second light intensity detector 3), and a third photoelectric detection It is composed of a connector 4 and a connector 5 for controlling the angle of incidence.

It should be noted that the parallel laser source capable of modulating light intensity with a light intensity detector; the laser source may be a low-power consumption vertical cavity surface emitting laser (VCSEL), or a DFB laser.

A light intensity detector (the first light intensity detector 1) is installed in the packaging cap of the laser light source, and the light detector can detect the light intensity change of the laser light source in real time.

The beam splitter of the parallel light transceiver module is used to divide the parallel beam emitted by the parallel laser light source into a reflected beam and a transmitted beam; the ratio of the intensity of the reflected beam and the intensity of the transmitted beam can be adjusted according to different design requirements . In general, the intensity of the reflected beam should be less than the intensity of the transmitted beam.

A detector with a high concentration of the gas to be measured is filled in the packaging cap of the second light intensity detector 3. Therefore, the incident laser light received by the photodetector is modulated by a high-concentration gas to be measured, and its output signal carries information about the absorption spectrum of the gas to be measured.

In another embodiment of the present invention, a photodetector with a reference gas chamber may also be replaced by a combination of a separate reference gas chamber and a photodetector.

In another embodiment of the present invention, two square cover plates on both sides of the light reflection ring can be provided with vent holes, and the measured gas diffuses from the vent holes into the gas absorption cell through a metal filter.

When the annular photoelectric gas sensing probe is in working state, the parallel laser source of the parallel light transceiver module is tuned and emits parallel light. The parallel beam is divided into a reflected beam and a transmitted beam by a beam splitter in the transceiver mode; the intensity of the reflected beam The ratio to the intensity of the transmitted light beam can be adjusted according to different design requirements.

The reflected light beam reflected by the beam splitter is received by a light intensity detector with a reference gas chamber to form a reference signal.

The transmitted light beam enters the light reflection ring from the light entrance and exit of the light reflection ring. The transmitted parallel light beam is incident into the light reflection ring at a specific design angle of incidence, and the working surface of the light reflection ring is reflected multiple times according to the designed number of reflections. The incident angle refers to the angle between the incident beam and the centerline of the light reflection ring. The size of the incident angle is controlled by the incident angle connector according to the design scheme, as shown in FIG. 6. The number of reflections of the incident light beam in the light reflection ring is determined by the incident angle. The number of multi-point reflections and the radius of the light reflection ring determine the total measured optical path length of the light beam in the light reflection ring, as shown in FIGS. 2 and 3.

After the reflected light beam has undergone its last reflection in the light reflection ring, it exits the light reflection ring from the light entrance and exit of the light reflection ring at the designed angle and is received by the third light intensity detector 4. The repeatedly reflected laser beam received by the detector is modulated by the gas to be measured, and its output signal carries information about the absorption spectrum of the gas to be measured to form a measurement signal for measuring the gas concentration.

In the ring-shaped photoelectric gas sensor probe, the inner wall of the upper and lower cover plates is coated with a black anti-reflection light coating in order to reduce the interference of stray light and play a role of preventing corrosion.

One of the multiple vent holes in the lower cover is equipped with a temperature sensor to detect the temperature in the gas absorption tank in real time. This temperature information will be used to compensate for parameter changes caused by ambient temperature fluctuations in order to further improve the measured gas. Precision.

A pressure sensor is provided in one of the plurality of vent holes in the lower cover plate, which is used to detect the pressure in the gas absorption tank in real time. This pressure information will be used to compensate for parameter changes caused by changes in air pressure at the sensor location, in order to further Improve measurement gas accuracy.

The solid cylinder on the lower cover is used to reduce the invalid volume inside the light reflection ring, which in turn reduces the total volume of the gas absorption cell in order to further reduce the measurement response time. The diameter of the solid cylinder is determined based on the size of the different angles of incidence. The radius of the cylinder should be less than the vertical distance from the first incident light to the center of the ring.

In this implementation example, when the condition "the radius of the cylinder should be smaller than the vertical distance from the first incident light to the center of the ring" is satisfied, all the reflected light beams satisfy this condition, and when adjusting the optical path, the first A beam of light is relatively easy.

In another embodiment of the present invention, the solid cylinder may be replaced with a hollow cylinder or a barrel structure.

The annular photoelectric gas sensor probe is arranged in a housing with a metal filter. The metal filter 6 is an optical element used to prevent dust, impurities and the like from entering the pollution light path inside the absorption cell, and it can be replaced during maintenance. The measured gas can be diffused from the vent hole into the gas absorption cell through a casing provided with a metal filter.

The annular photoelectric gas sensor probe is also provided with an electronic processing circuit for modulating the luminous intensity of the laser source and amplifying and adjusting the measurement signals of the three photodetectors.

The driving circuit of the laser light source of the present invention and the signal processing circuit of the three photodetectors can adopt the specific circuit structure described in the patent "A VCSEL-based low power consumption gas detection device and method" (CN102967580A).

The embodiment of the present invention further provides a photoelectric gas detection device, including the photoelectric gas sensor probe of the above embodiment.

The design of the circular multi-point reflection not only reduces the volume of the sensor probe absorption cell and increases the optical path length, but also greatly improves the stability and reliable behavior of the optical path, while reducing the difficulty of debugging and reducing Production and processing costs.

The above description is only a preferred embodiment of the present application, and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement, or improvement made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

A ring-shaped multi-point reflection type photoelectric gas sensor probe is characterized in that it includes a ring-shaped multi-point light reflection ring. The ring-shaped multi-point light reflection ring is a hollow cylindrical structure, and the upper and lower sides of the hollow cylindrical structure are respectively provided. There is a cover plate, a hollow cylinder structure and a cavity formed by the cover plate are gas absorption cells that contain the gas to be measured, and a center of one of the cover plates is provided with a cylinder that reduces the total volume of the gas absorption cell;

The hollow cylinder structure is provided with a beam entrance and exit opening, and a parallel light transceiver module is fixedly arranged at the opening. The parallel light transceiver module is used to generate parallel light and transmit the parallel light to the gas absorption cell for multiple reflections. Output.
The annular multi-point reflection type photoelectric gas sensor probe according to claim 1, wherein the cover plate is an upper cover plate and a lower cover plate, and one or both cover plates are provided with a plurality of cover plates. A vent hole, the gas to be measured diffuses from the vent hole into the gas absorption cell;

The inner wall of the cover plate is coated with a black coating for reducing reflected light.
The annular multi-point reflection type photoelectric gas sensor probe according to claim 2, wherein a pressure sensor for measuring the pressure in the gas absorption cell is installed in one of the plurality of ventilation holes;

Or a temperature sensor is installed in a vent hole for measuring the temperature in the gas absorption cell.
The ring-shaped multi-point reflection type photoelectric gas sensor probe according to claim 1, wherein the material of the ring-shaped multi-point light reflection ring is metal, plastic or synthetic material, and the ring-shaped multi-point light reflection ring Formed by machining or precision injection;

The inner wall of the annular multi-point light reflection ring is optically polished by a mirror surface, and is coated with a reflective film to form an arc reflecting mirror surface, or the inner wall of the annular multi-point light reflection ring is pasted with a reflective material to form an arc reflecting mirror surface.
The annular multi-point reflection type photoelectric gas sensor probe according to claim 1, wherein the parallel light transmitting / receiving module comprises: a parallel laser source, and the parallel laser source is connected to a first light intensity detector, The light intensity change of the parallel laser source is measured and modulated by a first light intensity detector, a second light intensity detector is connected to the reference gas chamber, and a light splitting is provided between the first light intensity detector and the second light intensity detector mirror;

The parallel beam emitted by the parallel laser source is divided into a reflected beam and a transmitted beam by a beam splitter. The reflected beam is received by the second light intensity detector to form a reference signal during measurement. The transmitted beam is incident on the gas absorption cell for multiple reflections. Light intensity detector output.
The annular multi-point reflection type photoelectric gas sensor probe according to claim 5, wherein the parallel laser source and the first light intensity detector are an integrated structure or a separate structure, and the second light intensity detection The device and the reference air chamber are an integrated structure or a separate structure;

A lens for focusing parallel light on a detection sensitive surface is provided in front of the third light intensity detector;

The beam splitter can adjust the ratio of the light intensity of the reflected light beam to the light intensity of the transmitted light beam.
The annular multi-point reflection type photoelectric gas sensor probe according to claim 5, wherein when the second light intensity detector and the reference gas chamber are integrated, the package of the second light intensity detector The cap is filled with a high-concentration gas to be measured. The incident laser light received by the second light intensity detector is modulated by the high-concentration gas to be measured, and its output signal carries information about the absorption spectrum of the gas to be measured.
The ring-shaped multi-point reflection type photoelectric gas sensor probe according to claim 5, wherein the transmitted light beam enters the ring-shaped multi-point light reflection ring through the beam exit opening, and the transmitted light beam is set at a predetermined The incident angle enters into the ring-shaped multi-point light reflection ring from the beam entrance and exit opening and is reflected multiple times by the circular mirror surface of the ring-shaped multi-point light reflection ring. The angle of incidence refers to the light reflection formed by the incident beam and the circular mirror The angle of the centerline of the ring;

The number of reflections of the incident light beam in the light reflection ring is determined by the radius of the light reflection ring and the incident angle, and the number of multi-point reflections determines the total length of the measured optical path of the light beam in the light reflection ring.
The annular multi-point reflection type photoelectric gas sensor probe according to claim 5, wherein the laser light source is connected to its driving circuit, a first light intensity detector, a second light intensity detector, and a third light intensity The detectors are connected to their respective signal processing circuits.
A photoelectric gas detection device, comprising the annular multi-point reflection type photoelectric gas sensor probe according to any one of claims 1-9.