Gas concentration detection device

Abstract

The utility model relates to the technical field of concentration measurement, in particular to a gas concentration detection device. The gas concentration detection device comprises a detection gas chamber which is internally provided with a light path channel, a gas inlet is formed in the detection gas chamber, the light path channel is communicated with the outside through the gas inlet, and at least one light reflecting piece is fixedly installed in the light path channel; the infrared laser and the infrared sensor are installed at the two ends of the light path channel respectively, infrared laser emitted by the infrared laser irradiates towards the light reflecting pieces, and the infrared laser faces the infrared sensor after being reflected by at least one light reflecting piece. The infrared laser emitted into the detection gas chamber is reflected by the reflecting part, so that the optical path of the infrared laser in a limited space can be prolonged, a longer infrared laser optical path can be obtained in a shorter detection gas chamber, and the calculation accuracy of the concentration of the to-be-detected gas can be greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of concentration measurement, and particularly relates to a gas concentration detection device. Background Art

[0002] When detecting natural gas leakage, it is judged whether the natural gas pipeline leaks by detecting whether the methane concentration exceeds the standard. However, methane is also produced by natural fermentation in nature. Therefore, there is a large false alarm rate in simply judging whether the natural gas pipeline leaks by detecting whether the methane concentration exceeds the standard. Since tetrahydrothiophene is an artificially synthesized odorant and does not exist in nature. Therefore, detecting the concentration of tetrahydrothiophene to monitor gas leakage can greatly reduce the false alarm rate of the system.

[0003] In the prior art, the concentration of tetrahydrothiophene is usually detected by an electro-chemical sensor. It installs an infrared sensor and an infrared light source in the gas chamber, and uses the sensor to monitor the wavelength of the infrared light received in real time, and monitors in real time through the infrared characteristic peak of tetrahydrothiophene. However, due to the short gas chamber of the detection device and the short optical path in the chamber, the accuracy of calculating the concentration of tetrahydrothiophene is poor. Summary of the Utility Model

[0004] Therefore, the technical problem to be solved by the utility model is to overcome the defect of poor accuracy of the tetrahydrothiophene concentration detection device in the prior art, so as to provide a gas concentration detection device.

[0005] To solve the above technical problem, the utility model provides a gas concentration detection device, including:

[0006] A detection gas chamber, which is internally provided with an optical path channel. An air inlet is arranged on the detection gas chamber, and the air inlet communicates the optical path channel with the outside. At least one reflecting member is fixedly installed in the optical path channel;

[0007] An infrared laser and an infrared sensor are respectively installed at both ends of the optical path channel. The infrared laser emits infrared laser light towards the reflecting member, and the infrared laser light is reflected by at least one reflecting member and then towards the infrared sensor.

[0008] Optionally, the optical path channel includes a first cavity and a second cavity that are sequentially connected. The infrared laser is installed at one end of the first cavity, the reflecting member is installed at the other end of the first cavity, and the reflecting member is arranged at an angle with the light emitting direction of the infrared laser. The infrared sensor is installed at one end of the second cavity far from the reflecting member.

[0009] Optionally, the first cavity and the second cavity are arranged in parallel and extend in parallel. Reflecting members are installed at both ends where the first cavity is connected to the second cavity and where the second cavity is connected to the first cavity.

[0010] Optionally, a spacer is provided between the first cavity and the second cavity.

[0011] Optionally, the infrared laser and the infrared sensor are installed on the same side of the detection gas chamber.

[0012] Optionally, an installation groove is provided on the outer side wall of the detection gas chamber. The installation groove communicates with the optical path channel, and the infrared laser and / or the infrared sensor are fixedly installed in the installation groove.

[0013] Optionally, a transmissive filter is installed between the infrared sensor and the optical path channel.

[0014] Optionally, a filter press block is fixedly installed in the installation groove, and the transmissive filter is installed between the filter press block and the installation groove.

[0015] Optionally, a plurality of air inlets are provided on different surfaces of the detection gas chamber.

[0016] Optionally, the central wavelength band of the laser emitted by the infrared laser is 6850 nm.

[0017] The technical solution of the present utility model has the following advantages:

[0018] 1. The gas concentration detection device provided by the present utility model includes: a detection gas chamber, inside which an optical path channel is provided. An air inlet is provided on the detection gas chamber, and the air inlet communicates the optical path channel with the outside. At least one reflecting member is fixedly installed in the optical path channel; an infrared laser and an infrared sensor are respectively installed at both ends of the optical path channel. The infrared laser light emitted by the infrared laser irradiates towards the reflecting member, and the infrared laser light is reflected by at least one reflecting member and then towards the infrared sensor.

[0019] When the gas concentration detection device is working, the infrared laser continuously emits infrared laser light. The infrared laser light is received by the infrared sensor after being reflected by the reflecting member. The infrared sensor monitors the wavelength data of the received infrared laser light in real time. When the gas from the outside enters the detection gas chamber through the air inlet, the infrared rays of some characteristic wavelengths are absorbed by the specific gas in the gas. The intensity of the infrared rays corresponding to the wavelengths monitored by the infrared sensor will decrease, resulting in characteristic peaks appearing in the infrared ray data monitored by the infrared sensor. By reflecting the infrared laser light incident into the detection gas chamber by the reflecting member, the optical path of the infrared laser light in the limited space can be extended. Moreover, by fixedly installing the infrared laser, the infrared sensor and the reflecting member, the optical path of the infrared laser light in the detection gas chamber is fixed, so that a longer optical path of the infrared laser light can be obtained in a shorter detection gas chamber, which can greatly improve the accuracy in calculating the concentration of the gas to be detected.

[0020] 2. The gas concentration detection device provided by the present utility model simplifies the optical path structure of the infrared laser by arranging the first cavity and the second cavity side by side and extending them in parallel, facilitating the calculation of the optical path of the infrared laser.

[0021] 3. In the gas concentration detection device provided by the present utility model, an installation groove is provided on the outer side wall of the detection gas chamber, and the installation groove is communicated with the optical path channel. The infrared laser and / or the infrared sensor are fixedly installed in the installation groove. This improves the installation stability of the infrared laser and the infrared sensor, making the overall gas concentration detection device an integrated connection structure, reducing the detection error caused by the misalignment of the infrared laser, the infrared sensor or the reflector due to equipment vibration, enhancing the overall stability of the device, and enabling the gas concentration detection device to be installed on moving mechanisms such as unmanned aerial vehicles and electric vehicle platforms for application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a schematic structural diagram of the gas concentration detection device provided in the embodiments of the present utility model.

[0024] Figure 2 It is a schematic internal structure diagram of the gas concentration detection device provided in the embodiments of the present utility model.

[0025] Description of the reference numerals: 1, infrared laser; 2, infrared sensor; 3, detection gas chamber; 4, laser mounting block; 5, transmissive filter; 6, filter pressing block; 7, first cavity; 8, second cavity; 9, air inlet; 10, reflector. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will clearly and completely describe the technical solutions of the present utility model with reference to the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present utility model.

[0027] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0028] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0029] In addition, the technical features involved in different embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0030] Figure 1 and Figure 2 As shown, a gas concentration detection device provided by this embodiment includes a detection gas chamber 3, an infrared laser 1 and an infrared sensor 2 fixedly installed on the detection gas chamber 3.

[0031] An optical path channel is provided inside the detection chamber 3. An air inlet 9 is provided on the detection chamber 3, and the air inlet 9 connects the optical path channel with the outside. At least one reflector 10 is fixedly installed in the optical path channel. In this embodiment, three air inlets 9 are provided on the side and top surfaces of the detection chamber 3. The infrared laser 1 and the infrared sensor 2 are fixedly installed at both ends of the optical path channel respectively. The infrared laser beam emitted by the infrared laser 1 irradiates towards the reflector 10, and the infrared laser beam is reflected by at least one reflector 10 and then towards the infrared sensor 2. Specifically, the optical path channel includes a first cavity 7 and a second cavity 8 that are connected in sequence. The infrared laser 1 is installed at one end of the first cavity 7, the reflector 10 is installed at the other end of the first cavity 7, and the reflector 10 is arranged at an angle with the light-emitting direction of the infrared laser 1. The infrared sensor 2 is installed at one end of the second cavity 8 away from the reflector 10. In this embodiment, the gas concentration detection device is used to detect tetrahydrothiophene, so the central wavelength band of the laser emitted by the infrared laser 1 is selected as the main absorption peak of tetrahydrothiophene, which is 6850 nm. In some other embodiments, the gas concentration detection device can also be used to detect other gases such as methane, and the central wavelength band of the laser emitted by the infrared laser 1 is then selected as the corresponding absorption peak band of other gases.

[0032] To facilitate the determination of the optical path length of the infrared laser beam propagating in the optical path channel, the first cavity 7 and the second cavity 8 are arranged side by side and extend in parallel. The infrared laser 1 and the infrared sensor 2 are installed on the same side of the detection chamber 3. Reflectors 10 are installed at both ends where the first cavity 7 is connected to the second cavity 8 and where the second cavity 8 is connected to the first cavity 7, and the included angle between the two reflectors 10 is 145°. In this embodiment, the reflector 10 is selected as a reflecting lens. In some other embodiments, the reflector can also be a reflecting surface polished or pasted inside the detection chamber 3. To prevent interference caused by the too-close distance between the first cavity 7 and the second cavity 8, a spacer is provided between the first cavity 7 and the second cavity 8.

[0033] To improve the installation stability of the infrared laser 1 and the infrared sensor 2, mounting grooves are provided on the outer side wall of the detection chamber 3. The mounting grooves communicate with the optical path channel, and the infrared laser 1 and the infrared sensor 2 are fixedly installed in the mounting grooves. To prevent ambient light from affecting the monitoring results, a transmissive filter 5 is installed between the infrared sensor 2 and the optical path channel. To improve the stability of the transmissive filter and prevent it from shaking in the mounting groove, a filter block 6 is fixedly installed in the mounting groove by bolts, and the transmissive filter 5 is installed between the filter block 6 and the mounting groove. The infrared laser 1 is fixedly installed in the corresponding mounting groove through a laser mounting block 4. The laser mounting block 4 is fixedly installed at the bottom of the detection chamber 3 by bolts, and the infrared laser 1 is fixedly installed between the laser mounting block 4 and the mounting groove by bolts.

[0034] In the gas concentration detection device provided in this embodiment, the infrared laser 1 is fixedly connected to the laser mounting block 4 by screw connection, the laser mounting block 4 is fixed to the detection gas chamber 3 by bolts, the reflecting lens is bonded inside the detection gas chamber 3 with ultraviolet UV glue, the transmission filter 5 is fixed to the tail of the detection gas chamber 3 by the filter press block 6, and the infrared sensor 2 is fixed to the outer wall at the tail of the detection gas chamber 3 by bolts. Two reflecting lenses are bonded inside the detection gas chamber 3, and the reflection of the light beam by the reflecting mirror can effectively increase the optical path, which is beneficial to more conveniently calculate the concentration of the gas. The length of the detection gas chamber 3 is lengthened compared with the length of the traditional gas chamber, and its length is 100 mm to achieve the purpose of increasing the optical path, facilitating measurement, and making the monitoring results more accurate. Two reflecting lenses are installed inside the detection gas chamber 3, and at the same time, two sequentially connected cavities are formed inside the detection gas chamber 3, namely the first cavity 7 and the second cavity 8. The structural design of the detection gas chamber 3 enables the infrared laser 1, the detection gas chamber 3, the transmission filter 5, and the infrared sensor 2 to be integrally connected.

[0035] When assembling the gas concentration detection device, first tighten the infrared laser 1 on the laser mounting block 4, align the four threaded holes on the laser mounting block 4 with the corresponding threaded holes on the detection gas chamber 3, and fix the laser mounting block 4 to the tail of the detection gas chamber 3 by bolts. Then place the transmission filter 5 in the circular hole in the mounting groove at the bottom tail of the detection gas chamber 3, then press the filter lens press block on the transmission filter 5, and use bolts to fix the filter lens press block to the detection gas chamber 3. Next, align the two threaded holes on the infrared sensor 2 with the two threaded holes on the filter lens press block, and use bolts to connect the infrared sensor 2 and the filter lens press block.

[0036] When using the gas concentration detection device to detect the concentration of tetrahydrothiophene, make the gas to be measured enter the detection gas chamber 3 through the air inlet 9, start the infrared laser 1 to emit infrared laser, pass through the gas to be measured in the first cavity 7 of the detection gas chamber 3, and the infrared laser reaches the reflecting lens installed at the end of the second cavity 8 after being reflected by the reflecting lens at the end of the first cavity 7. After being reflected twice, it passes through the second cavity 8, and then passes through the filtering of the transmission filter 5 to reach the infrared sensor 2. Finally, the infrared sensor 2 is connected to the data analysis unit through a circuit to analyze and calculate the concentration of tetrahydrothiophene. By reflecting the infrared laser incident into the detection gas chamber 3 through the reflector 10, the optical path of the infrared laser in the limited space can be extended, and by fixedly installing the infrared laser 1, the infrared sensor 2, and the reflector 10, the optical path of the infrared laser in the detection gas chamber 3 is fixed, so that a longer infrared laser optical path can be obtained in the shorter detection gas chamber 3, which can greatly improve the accuracy when calculating the concentration of the gas to be detected.

[0037] As an alternative embodiment, the optical path channel can also be set as multiple chambers, and multiple reflecting lenses are installed in the multiple chambers. It is only necessary to ensure that the infrared laser emitted by the infrared laser 1 can be received by the infrared sensor 2 after being reflected by the reflecting lenses.

[0038] Obviously, the above embodiments are only examples given for clear illustration, rather than limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or alterations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or alterations derived therefrom are still within the protection scope of the present invention.

Claims

1. A gas concentration detection device, characterized in that: include: A detection air chamber (3) having an optical path channel disposed therein, an air inlet (9) disposed on the detection air chamber (3), the air inlet (9) connecting the optical path channel with the outside, and at least one reflector (10) fixedly mounted in the optical path channel; An infrared laser (1) and an infrared sensor (2) are respectively mounted at two ends of the optical path; the infrared laser (1) emits infrared laser light toward the reflector (10); and the infrared laser light is reflected by at least one of the reflectors (10) and then directed toward the infrared sensor (2).

2. The gas concentration detection device according to claim 1, characterized in that: The optical path comprises a first cavity (7) and a second cavity (8) which are connected in sequence, the infrared laser (1) is mounted at one end of the first cavity (7), the reflector (10) is mounted at the other end of the first cavity (7), the reflector (10) is arranged at an angle with respect to the light emitting direction of the infrared laser (1), and the infrared sensor (2) is mounted at one end of the second cavity (8) away from the reflector (10).

3. The gas concentration detection device according to claim 2, characterized in that: The first cavity (7) and the second cavity (8) are arranged side by side and extend in parallel, and the reflective element (10) is installed at one end of the first cavity (7) connected to the second cavity (8) and at one end of the second cavity (8) connected to the first cavity (7).

4. The gas concentration detection device according to claim 2 or 3, characterized in that: A partition is provided between the first cavity (7) and the second cavity (8).

5. The gas concentration detection device according to any one of claims 1 to 3, characterized in that: The infrared laser (1) and the infrared sensor (2) are installed on the same side of the detection gas chamber (3).

6. The gas concentration detection device according to any one of claims 1 to 3, characterized in that: An installation groove is provided on the outer side wall of the detection air chamber (3), the installation groove is communicated with the optical path channel, and the infrared laser (1) and / or the infrared sensor (2) are fixedly installed in the installation groove.

7. The gas concentration detection device according to claim 6, characterized in that: A transmission filter (5) is installed between the infrared sensor (2) and the optical path channel.

8. The gas concentration detection device according to claim 7, characterized in that: A filter pressing block (6) is fixedly installed in the installation groove, and the transmission filter (5) is installed between the filter pressing block (6) and the installation groove.

9. The gas concentration detection device according to any one of claims 1 to 3, characterized in that: A plurality of air inlets (9) are arranged on different surfaces of the detection air chamber (3).

10. The gas concentration detection device according to any one of claims 1 to 3, characterized in that: The central wavelength band of the laser light emitted by the infrared laser (1) is 6850 nm.

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