1. A photoelectric gas sensor probe comprises a multipoint reflection two-dimensional light path module body, a first plane reflector, a second plane reflector, a parallel light source and a photoelectric detector, wherein the first plane reflector, the second plane reflector, the parallel light source and the photoelectric detector are embedded in the light path module body; a gas absorption pool for containing gas to be detected is formed in the light path module body, and the gas to be detected enters the gas absorption pool from the upper part of the light path module body; the reflection surface of the first plane reflector and the reflection surface of the second plane reflector are oppositely arranged and are parallel to each other, and the centers of the first plane reflector and the second plane reflector are not on the same straight line; the triangular reflector fixture blocks are respectively arranged in the middle of the reflecting surfaces of the first planar reflector and the second planar reflector and used for fixing the first planar reflector and the second planar reflector; the angle of the sharp corner corresponding to the two reflector fixture blocks is consistent with the reflection angle of the parallel light beam emitted by the parallel light source; and the parallel light beams are received by the photoelectric detector after being reflected for multiple times by the first plane reflector and the second plane reflector.

2. The photoelectric gas sensor probe of claim 1, wherein the triangular mirror fixture block has a cross-sectional shape of an isosceles triangle.

3. The photoelectric gas sensor probe of claim 1, wherein the optical path module body is provided with a slot for mounting the first planar reflector and the second planar reflector, and the bottom of the slot is on the same horizontal plane as the bottom of the reflector fixture block.

4. The photoelectric gas sensor probe according to claim 3, wherein heating sheets for heating are respectively disposed on the back surfaces of the first and second flat mirrors, and the heating sheets are respectively disposed on the back surfaces of the first and second flat mirrors.

5. The photoelectric gas sensor probe according to claim 3, wherein the slot is filled with a heat insulating material for covering the first plane mirror, the second plane mirror and the heating plate.

6. The photoelectric gas sensor probe of claim 1, wherein the optical path module body has a sensor at its bottom for detecting the temperature and pressure in the absorption cell, and the output signal of the sensor is used for compensation in calculating the gas concentration.

7. The photoelectric gas sensor probe of claim 5, wherein the collimated light source comprises a laser with a light intensity detector and a collimated light lens, and the laser emits a collimated light beam through the collimated light lens; and a focusing lens is arranged at the front end of the photoelectric detector and is used for focusing the parallel light beams on a photosensitive surface of the photoelectric detector.

8. The optoelectronic gas sensor probe of claim 7, further comprising a probe housing, the probe housing comprising an upper housing and a lower housing, the optoelectronic gas sensor probe disposed within a cavity formed by the upper housing and the lower housing; the lower shell is also embedded with a driving circuit module and a signal processing circuit module, and the parallel light source and the heating plate are respectively electrically connected with the driving circuit module; and the detector, the photoelectric detector and the temperature and pressure sensor of the laser are electrically connected with the signal processing circuit module.

9. The photoelectric gas sensor probe head of claim 8, wherein the driving circuit module further comprises an embedded control module for collecting the output signals of the detector and the photodetector of the laser, analyzing and calculating the output signals, and controlling the heating driving current to control the on/off of the heating sheet driving circuit.

10. An optoelectronic gas sensing device comprising an optoelectronic gas sensor probe as claimed in any one of claims 1 to 9.

Background

At present, in order to meet the increasing requirements of environmental safety detection and production safety monitoring, various photoelectric gas sensors based on Tunable Diode Laser Absorption Spectroscopy (TDLAS) technology are continuously developed and used in actual production to realize real-time and online detection and measurement. The Tunable Diode Laser Absorption Spectrum (TDLAS) technology utilizes the characteristics of tunability and narrow spectral line width of a semiconductor laser, and enables the laser wavelength to be accurately aligned to the absorption peak of the gas to be detected by a method of tuning the laser wavelength at the spectral absorption peak of the gas to be detected, so that the gas concentration can be rapidly detected. Meanwhile, the interference caused by other gases to the measurement is also avoided. In the sensors, advanced digital signal processing technology can not only realize continuous measurement of the concentration of the gas to be measured, but also can carry out real-time measurement on the temperature, the pressure and the humidity of the measured site, and the environmental data can enable the novel gas sensor to have the functions of automatic diagnosis and self-correction, thereby enabling the laser spectrum gas sensors to be widely applied to different production processes and safety precaution fields.

In the design of these gas sensor probes, in order to improve the measurement accuracy, it is usually necessary to increase the total length of the optical path as much as possible in the limited size of the gas absorption cell, and a method is generally adopted in which a plurality of mirrors are used to reflect the optical path in the gas absorption cell for a plurality of times, so as to achieve the purposes of increasing the length of the measurement optical path, and reducing the volume of the gas chamber and the size of the sensing probe, and the mirrors are usually adhered to fixed positions in the gas absorption cell so as to form a fixed optical path. When such gas sensors are used in environments where the temperature varies widely and is highly humid, the environmental conditions of the sensor can have at least two adverse effects on the mirrors, namely condensation of water on the mirrors due to temperature differences and de-wetting of the mirrors due to moisture.

Therefore, when the sensor is applied to a practical application site, the key technical problems which must be solved are how to prevent the reflector from being condensed and how to solve the problem that the viscose is moistened and degummed.

Disclosure of Invention

Therefore, in order to solve the problems in the prior art, one of the objectives of the present invention is to provide an anti-condensation and non-degumming photoelectric gas sensor probe, in which a triangular reflector fixture block is arranged to fix a parallel reflector, and no adhesive reflector is needed, so as to effectively avoid the problem of adhesive being wetted and degummed, reduce the volume of an absorption cell, increase the measurement optical path, greatly improve the stability and reliability of the optical path, and reduce the production and processing costs while reducing the debugging difficulty in production.

Meanwhile, the heating sheet adhered to the rear sides of the two plane reflectors is connected with a heating driving circuit and is controlled by a temperature sensor carried by the sensor and a light intensity difference value detected by a laser light intensity detector and a photoelectric detector, when the light intensity difference value is increased to a preset starting threshold value, the control circuit sends a starting heating signal, and heating driving current keeps the temperature of the mirror surface higher than the ambient temperature through the heating sheet, so that the mirror surface keeps a non-condensation state.

The purpose of the invention is realized by adopting the following technical scheme:

a photoelectric gas sensor probe comprises a multipoint reflection two-dimensional light path module body, a first plane reflector, a second plane reflector, a parallel light source and a photoelectric detector, wherein the first plane reflector, the second plane reflector, the parallel light source and the photoelectric detector are embedded in the light path module body; a gas absorption pool for containing gas to be detected is formed in the light path module body, and the gas to be detected enters the gas absorption pool from the upper part of the light path module body; the reflection surface of the first plane reflector and the reflection surface of the second plane reflector are oppositely arranged and are parallel to each other, and the centers of the first plane reflector and the second plane reflector are not on the same straight line; the triangular reflector fixture blocks are respectively arranged in the middle of the reflecting surfaces of the first planar reflector and the second planar reflector and used for fixing the first planar reflector and the second planar reflector; the angle of the sharp corner corresponding to the two reflector fixture blocks is consistent with the reflection angle of the parallel light beam emitted by the parallel light source; and the parallel light beams are received by the photoelectric detector after being reflected for multiple times by the first plane reflector and the second plane reflector.

As a further explanation of the above scheme, the cross-sectional shape of the triangular mirror fixture block is an isosceles triangle.

As a further explanation of the above scheme, a clamping groove for mounting the first planar reflector and the second planar reflector is arranged on the light path module body, and inner walls on two sides of the clamping groove and the bottom of the reflector clamping block are on the same horizontal plane.

As a further explanation of the above scheme, heating sheets for heating the first planar reflector and the second planar reflector are further respectively arranged in the card slot, and the heating sheets are respectively attached to the back surfaces of the first planar reflector and the second planar reflector.

As a further explanation of the above scheme, the first plane mirror, the second plane mirror, the heating plate, and the mirror fixture block are all fixed on the inner walls of the two sides of the fixture groove by screws.

As a further explanation of the above scheme, a heat insulator for covering the first planar reflector, the second planar reflector and the heating plate is filled in the slot.

As a further explanation of the above scheme, a sensor for detecting the temperature and the air pressure in the absorption cell is arranged at the bottom of the optical path module body, and an output signal of the sensor is used for compensation when calculating the gas concentration.

As a further explanation of the above solution, the collimated light source includes a laser with a light intensity detector and a collimated light lens, and the laser emits a collimated light beam through the collimated light lens; and a focusing lens is arranged at the front end of the photoelectric detector and is used for focusing the parallel light beams on a photosensitive surface of the photoelectric detector.

As a further explanation of the above scheme, the photoelectric gas sensor probe further comprises a probe shell, the probe shell comprises an upper shell and a lower shell, and the photoelectric gas sensor probe is arranged in a cavity formed by the upper shell and the lower shell; the lower shell is also provided with a driving circuit module and a signal processing circuit module, and the parallel light source and the heating plate are respectively electrically connected with the driving circuit module; and the detector, the photoelectric detector and the temperature and pressure sensor of the laser are electrically connected with the signal processing circuit module.

As a further explanation of the above scheme, the driving circuit module further includes an embedded control module for acquiring output signals of a detector and a photodetector of the laser, analyzing and calculating the output signals, and controlling the heating driving current to control the on/off of the heating sheet driving circuit.

As a further explanation of the above scheme, a plurality of gas inlet holes are arranged at the top of the upper shell; and a filter screen is also arranged above the gas inlet hole.

As a further explanation of the above scheme, the inner wall and the top of the light path module body are coated with black coating for reducing reflected light.

Another object of the present invention is to provide a photoelectric gas detecting apparatus, which includes the photoelectric gas sensor probe.

Compared with the prior art, the invention has the beneficial effects that:

1. the parallel reflectors are fixed by the triangular reflector fixture blocks and the inner walls of the two sides of the fixture groove of the reflector, the reflector does not need to be adhered by glue, the problem that the glue is affected with damp and degummed is effectively solved, the volume of the absorption pool is reduced, the measuring optical path is increased, the stability and reliability of the optical path are greatly improved, and the production and processing cost is reduced while the debugging difficulty in production is reduced;

2. in addition, the invention adopts the receiving and transmitting design of the parallel light source and the photoelectric detector with the focusing lens, and ensures the precision of the parallel mirror surfaces of the two plane reflectors by utilizing the high precision and the size consistency of precision machinery, thereby reducing the difficulty of adjusting the light path in the actual production; the integral invention design not only reduces the complexity of the production process, but also improves the yield of the product, and is convenient for large-scale production;

3. meanwhile, the heating plate is arranged behind the plane reflector, and the driving circuit of the heating plate is started/shut off by utilizing the temperature information of the air chamber and the difference value of two average light intensities of the parallel laser beams monitored by the light intensity detector and the photoelectric detector of the laser, so that the temperature of the plane reflector is always kept higher than the ambient temperature by the sensor in a low-temperature state, the problem of water condensation on the plane reflector surface is avoided, and the use stability is improved;

4. according to the invention, the two-dimensional light path is formed by multi-point reflection generated by the double parallel reflectors, so that the total detection light path is increased in the absorption cell, and the detection signal-to-noise ratio and the measurement precision are improved; the volume of the sensor probe is reduced due to the multi-point reflection two-dimensional light path, so that the response time of measurement is reduced.

Drawings

Fig. 1 is a schematic diagram of a multi-point reflection two-dimensional optical path of an optical path module body in a photoelectric gas sensor probe according to embodiment 1 of the present invention;

FIG. 2 is a schematic sectional view of an optical path module body in the photoelectric gas sensor probe of embodiment 1 of the present invention;

fig. 3 is a schematic structural diagram of the optical path module body in the photoelectric gas sensor probe of embodiment 1 of the present invention, which is disposed in the probe housing.

In the figure: 1. a light path module body; 11. a card slot; 2. a first planar mirror; 3. a second planar mirror; 4. a collimated light source; 5. a photodetector; 6. a mirror fixture block; 7. a heating plate; 8. a sensor; 9. a screw; 100. a probe housing; 101. an upper housing; 102. a lower housing; 103. an air inlet; 104. filtering with a screen; 105. a driving circuit module; 106. and a signal processing circuit module.

Detailed Description

In order to facilitate understanding of the present invention, the technical solution and advantages of the photoelectric gas sensor probe according to the present invention will be described in further detail with reference to the accompanying drawings and embodiments. The following description is given by way of example to specific structures and features of an optoelectronic gas sensor probe and should not be construed as limiting the invention in any way. Also, any feature described (including implicit or explicit) in connection with any following discussion, and any feature shown or implicit in the drawings may be combined or subtracted from any other feature described or implicit in any other embodiment to form any further embodiment that may not be mentioned directly or indirectly in the present disclosure. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

In the description of the present invention, unless otherwise specified, the terms "top," "bottom," "left," "right," "relative," and the like, as used herein, are intended to refer to an orientation or positional relationship as shown in the accompanying drawings, which is for convenience and simplicity of description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

EXAMPLE 1 photoelectric gas sensor Probe

As shown in fig. 1-3, a photoelectric gas sensor probe comprises a multi-point reflection two-dimensional light path module body 1, a first plane mirror 2, a second plane mirror 3, a parallel light source 4, and a photoelectric detector 5, which are embedded in the light path module body 1; a gas absorption pool for containing gas to be detected is formed in the light path module body 1, and the volume in the light path module body is used for containing the gas to be detected; the gas to be measured enters the gas absorption cell from the upper part of the light path module body 1; the reflecting surfaces of the first plane reflecting mirror 2 and the second plane reflecting mirror 3 are oppositely arranged and are parallel to each other, and the centers of the first plane reflecting mirror 2 and the second plane reflecting mirror 3 are not on the same straight line; the triangular reflector fixture block 6 is respectively arranged in the middle of the reflecting surfaces of the first plane reflector 2 and the second plane reflector 3 and used for fixing the first plane reflector 2 and the second plane reflector 3; the relative sharp angle angles of the two reflector fixture blocks 6 are consistent with the reflection angle of the parallel light beam emitted by the parallel light source 4; the parallel light beams are received by the photoelectric detector 5 after being reflected for multiple times by the first plane mirror 2 and the second plane mirror 3.

In the embodiment, the triangular reflector fixture block 6 is arranged to fix the parallel reflector, so that the reflector does not need to be adhered by glue, the problem that the glue is wetted and degummed is effectively solved, the volume of the absorption tank is reduced, the optical path measurement is increased, the stability and reliability of the optical path are greatly improved, and the production and processing cost is reduced while the debugging difficulty in production is reduced;

in addition, the invention adopts the receiving and transmitting design of the parallel light source and the photoelectric detector with the focusing lens, and ensures the precision of the parallel mirror surfaces of the two plane reflectors by utilizing the high precision and the size consistency of precision machinery, thereby reducing the difficulty of adjusting the light path in the actual production; the whole invention design not only reduces the complexity of the production process, but also improves the yield of the product, and is convenient for large-scale production.

As shown in fig. 1, in the present embodiment, the reflecting surfaces of the first and second plane mirrors 2 and 3 are oppositely disposed and parallel to each other, and the centers of the first and second plane mirrors 2 and 3 are not in the same line, and there is an offset distance between the centers, when a parallel light beam from the parallel light source is irradiated onto the first plane mirror 2 at an incident angle, its reflected light beam will be directed to the second plane mirror 3 at the same incident angle, and the second reflected light beam will be reflected to the first plane mirror 2 at the same incident angle, and the reflected light beam will continue to be reflected twice between the first and second plane mirrors 2 and 3 until the final reflected light beam is received by a photo detector 5 and the photo detector 5 converts the optical signal into an electronic signal.

The multipoint reflection two-dimensional light path photoelectric gas sensor probe produced by the double parallel reflectors reduces the possibility of change of relative positions of all components and improves the stability of a light path system because the whole two-dimensional light path is embedded in a complete metal or synthetic material module body.

In this embodiment, the optical path module body 1 may be made of a solid material such as metal, plastic, or a composite material, the multi-point light reflection two-dimensional optical path may be formed by machining or precision injection molding, and the multi-point light reflection two-dimensional optical path is composed of five straight optical paths between two plane mirrors and is embedded in the optical path module body 1.

In the invention, after the incident laser received by the photoelectric detector is modulated by the gas to be measured with a certain concentration, the output signal of the laser carries the information of the absorption intensity of the gas to be measured at the absorption spectrum.

In a further preferred embodiment, the cross-sectional shape of the triangular mirror block 6 is an isosceles triangle.

As a further preferred embodiment, the optical path module body 1 is provided with a slot 11 for mounting the first plane mirror 2 and the second plane mirror 3, and inner walls of two sides of the slot 11 and the bottom of the mirror fixture block 6 are on the same horizontal plane. The design has the advantages that when the first plane reflector and the second plane reflector are installed, the reflecting surfaces of the first plane reflector and the second plane reflector can be simultaneously in close contact with the inner walls of the two sides of the corresponding clamping groove and the bottom wall of the reflector clamping block, and then the first plane reflector and the second plane reflector are respectively pressed on the inner walls of the two sides of the corresponding clamping groove and the bottom of the reflector clamping block by using plastic head screws, so that the purpose of fixing the first plane reflector and the second plane reflector on the two sides of the absorption cell can be achieved;

because the first plane reflector 2 and the second plane reflector 3 are mechanically fixed on two sides of the gas absorption cell by the screws 10, the gluing process is not needed, so the design effectively avoids the problem of glue wetting and degumming; another function of the mirror card blocks is to reduce the effective space of the detection air chamber, thereby reducing the measurement response time of the sensor.

In a further preferred embodiment, the card slot 11 is further provided with a heating sheet 7 for heating the first and second flat mirrors 2 and 3, respectively, and the heating sheet 7 is closely attached to the back surfaces of the first and second flat mirrors 2 and 3, respectively.

In the present embodiment, the size of the heating sheet 7 is smaller than the first and second plane mirrors 2 and 3; the heating plate 7 is an ultra-micro Metal ceramic heating element, namely Metal Ceramics Heater (MCH), the element is a high-efficiency, energy-saving and environment-friendly ceramic heating element, and compared with an alloy wire and a PTC ceramic heating element, the MCH has the advantages of corrosion resistance, uncharged surface of the heating element, cold and heat impact resistance, long service life, uniform heating, high heat conduction efficiency, accordance with the environmental protection requirements of European Union RoHS and the like. The micro MCT has high thermal response, and can directly and effectively heat the reflecting part of the reflector by adhering to the back surface of the reflector having insulation property.

In a further preferred embodiment, the first plane mirror 2, the second plane mirror 3, the heating plate 7 and the mirror block 6 are fixed on the inner walls of the two sides of the slot 11 by screws.

In a more preferred embodiment, the heat insulating material for covering the first and second flat mirrors 2 and 3 and the heater chip 7 is filled in the cavity 11. In this embodiment, after the first plane mirror 2, the second plane mirror 3, and the heating plate 7 are installed and debugged, the heat insulating material is filled in the slots, so as to ensure that all the heat generated by the heating plate is used for heating the mirror, thereby effectively reducing the power consumption required for heating. The MCT can heat under low voltage, so that the voltage value on the heating sheet can be controlled in real time, and the dynamic adjustment and switching of the working state and the rest state of the heating sheet are realized, thereby further reducing the power consumption of the whole measuring system.

As a further preferred embodiment, the bottom of the optical path module body 1 is provided with a sensor 9 for detecting the temperature and the air pressure in the absorption cell, and the output signal of the sensor is used for compensation when calculating the gas concentration. In this embodiment, the sensor 9 is arranged to detect in real time the temperature and pressure values in the gas cell, and the measured temperature and pressure information will be used to compensate for parameter variations due to ambient temperature and local pressure fluctuations, in order to further improve the accuracy of the measured gas.

As a further preferred embodiment, the parallel light source 4 includes a laser (not shown in the drawings) with a light intensity detector and a parallel light lens (not shown in the drawings), and the laser emits a parallel light beam through the parallel light lens; and a focusing lens is arranged at the front end of the photoelectric detector and is used for focusing the parallel light beams on a photosensitive surface of the photoelectric detector. The parallel light source is a parallel laser source which is provided with a light intensity detector and can modulate light intensity; the laser source can be a low-power Vertical Cavity Surface Emitting Laser (VCSEL) or a DFB laser; the light intensity detector is installed in the packaging cap of the laser, and the light detector can detect the light intensity change of the laser light source in real time.

As a further preferred embodiment, the photoelectric gas sensor probe further comprises a probe shell 100, wherein the probe shell 100 comprises an upper shell 101 and a lower shell 102, and the photoelectric gas sensor probe is arranged in a cavity formed by the upper shell 101 and the lower shell 102; the lower shell 102 is further provided with a driving circuit module 105 and a signal processing circuit module 106, and the parallel light source 4 and the heating plate 7 are respectively electrically connected with the driving circuit module 105; and the detector, the photoelectric detector and the temperature and pressure sensor of the laser are electrically connected with the signal processing circuit module.

In this embodiment, the temperature sensor and the laser intensity detector of the sensor transmit signals to the driving circuit module by detecting the real-time temperature of the absorption cell, comparing the corresponding dew point temperature, and detecting and comparing the laser intensity received by the laser intensity detector and the photodetector, and control the heating driving current to heat the heating plate, so as to keep the temperature of the mirror surface 2 to 4 ℃ higher than the ambient temperature, thereby keeping the mirror surface in a non-condensed water state.

As a further preferred embodiment, the driving circuit module further includes an embedded control module (not shown in the figure) for acquiring output signals of the detector and the photodetector of the laser, analyzing and calculating the output signals, and controlling the heating driving current to control the on/off of the heating sheet driving circuit.

In this embodiment, the heating control principle and process of the heating sheet after the sensor transmits the signal are specifically that the sensor works in a low-temperature and high-humidity environment, when the temperature of the air chamber is lower than a preset dew point temperature, and meanwhile, if the light intensity measured by the light intensity detector of the laser is not changed, the light intensity of the parallel light beams after multiple reflections detected by the photoelectric detector is weakened, that is, the difference between the light intensities detected by the two detectors is increased, which indicates that trace water condensation may be generated at the specular reflection point; if the light intensity value of the laser obtained by the photoelectric detector is reduced to a preset value or the light intensity difference value detected by the two detectors is increased to a starting preset value, the circuit for controlling the heating sheet starts to start, the driving current of the heating sheet is gradually increased, so that the heating sheet locally heats the reflection point of the reflector surface until the light intensity value of the parallel light beam obtained by the photoelectric detector is increased back to the original normal value or the light intensity difference value detected by the two detectors is reduced to a switching-off preset value, and the heating sheet control circuit gradually reduces the current applied to the heating sheet again, so that the local heating is reduced or even the heating is stopped. By detecting the temperature of the air chamber and detecting and comparing the laser intensity values obtained by the laser detector and the photoelectric detector, the working state of the heating sheet can be effectively and dynamically adjusted and controlled, the laser value obtained by the detector is ensured to be always larger than a normal value, namely, the mirror reflection point is ensured not to generate water condensation which influences the laser intensity through the local heating of the heating sheet, so that the aim of preventing water condensation is fulfilled.

In summary, the start and the shutdown of the driving circuit of the heating plate are controlled by the embedded control module, and the start or the shutdown is determined by the actually measured temperature value of the air chamber and the difference value between the light intensity value measured by the detector of the laser and the average light intensity value of the parallel laser beam monitored by the photoelectric detector (when the average light intensity is smaller than or larger than the preset value, the driving circuit of the heating plate is started/shut down). When the temperature of the air chamber is lower than a preset temperature value, when the average light intensity difference value monitored by a detector of the laser and a photoelectric detector is larger than a preset threshold value, starting the heating sheet; when the average light intensity difference is smaller than the light intensity threshold value, the heating sheet is switched off. The invention can effectively and dynamically adjust and control the working state of the heating sheet; the intelligent control is more accurate, and simultaneously, the working energy consumption of the sensor probe is also reduced.

As a further preferred embodiment, a plurality of gas inlet holes 103 are arranged on the top of the upper shell 101; a filter screen 104 is also arranged above the gas inlet hole 103.

In this embodiment, the filter screen 104 is a metal sintered filter screen, and the gas to be measured diffuses into the gas absorption cell through the sintered filter screen 104; the filter screen 104 is used for preventing dust, impurities and the like from entering the absorption cell to pollute optical elements in an optical path, can be replaced during maintenance and is convenient to operate.

As a further preferred embodiment, the inner wall and the top of the light path module body 1 are coated with black coating layers for reducing reflected light; so as to reduce the interference of stray light and to function as corrosion protection.

The working principle of the photoelectric gas sensor probe of the embodiment 1 is as follows: when one parallel light beam irradiates the first plane mirror at an incident angle from the parallel light source, the reflected light beam of the parallel light beam irradiates the second plane mirror at the same incident angle, the reflected light beam of the second parallel light beam reflects at the same incident angle to the first plane mirror, and the reflected light beam continuously reflects twice between the first plane mirror and the second plane mirror until the final reflected light beam is received by a photoelectric detector, and the photoelectric detector converts the optical signal into an electronic signal.

EXAMPLE 2 photoelectric gas detection device

The present invention also provides a photoelectric gas detection apparatus including the photoelectric gas sensor probe of embodiment 1 described above.

The above-described embodiments are merely preferred embodiments of the present invention and the scope of the present invention should not be limited thereto, and it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations can be made thereto without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.