A truncated ellipsoidal cell for multichannel non-dispersive infrared gas detection

Abstract

The application discloses a truncated ellipsoid type gas chamber for multichannel nondispersive infrared gas detection and relates to the technical field of gas detection. The truncated ellipsoid type gas chamber for multichannel nondispersive infrared gas detection comprises an optical gas chamber unit, a plurality of optical gas chamber units are arranged on a substrate, and a reflection cavity is formed in the optical gas chamber unit by being concave. The side wall of the reflection cavity is in an ellipsoid arc shape, the first focus and the second focus of the side wall are located on the surface of the substrate, the first focus of the ellipsoid side wall of at least two reflection cavities is coincident, a sensor is arranged at the first focus, a light source is arranged at the second focus, and the light emitted by the light source is reflected to the sensor through the side wall of the reflection cavity. According to the technical scheme, the first focus of the reflection cavity of the plurality of ellipsoid arc side walls is coincident, the sensor is arranged at the first focus, and the light source is arranged at the second focus, so that the light path emission paths of the plurality of optical gas chamber units are unified, the calibration difficulty is reduced, and the detection efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of gas detection technology, and in particular to a truncated ellipsoidal gas chamber for multi-channel non-dispersive infrared gas detection. Background Technology

[0002] Non-dispersive infrared (NDIR) gas detection technology inverts concentration by measuring the absorption attenuation of light intensity in the characteristic mid-infrared band of a target gas. It has advantages such as good selectivity, high stability, and suitability for long-term online detection. With the development of environmental monitoring, industrial safety, portable detection, and IoT node applications, NDIR gas sensors are evolving towards miniaturization, multi-gas detection, and board-level integration.

[0003] Among related technologies, there is a multi-gas NDIR integrated optical cell scheme, which realizes multi-gas detection through multiple light sources, filter structures and detection units. However, the complexity of the structure and calibration increases with the increase of the number of system channels. Although there are also ellipsoidal or asymmetric ellipsoidal reflective cells for the detection of gases such as methane, existing ellipsoidal cells are mostly designed for single gases or single optical paths. When performing multi-gas detection, it is difficult to achieve compact integration of multiple channels. Even if multi-gas detection is achieved, it will occupy a lot of space, which is not conducive to the assembly of other structures. Summary of the Invention

[0004] The main objective of this invention is to propose a truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection, aiming to solve the technical problem that existing ellipsoidal reflective gas cells are only suitable for single gas detection and are difficult to achieve compact integration of multiple channels.

[0005] To achieve the above objectives, the present invention proposes a truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection, comprising: An optical air cell unit, wherein multiple optical air cell units are disposed on a substrate, and a reflective cavity is formed in the recess of each optical air cell unit; The sidewall of the reflective cavity is an ellipsoidal arc surface, and the first focus and the second focus of the sidewall are both located on the surface of the substrate. The first focus of at least two of the ellipsoidal sidewalls of the reflective cavity coincides. A sensor is provided at the first focus and a light source is provided at the second focus. Light emitted by the light source is reflected by the sidewall of the reflective cavity to the sensor.

[0006] In one embodiment, the first focal point is located outside the reflecting cavity, and the second focal point is located inside the reflecting cavity.

[0007] In one embodiment, the optical cell unit includes a cell body, which is a quarter-ellipsoidal structure. A first opening is provided on the side of the optical cell unit between the first focal point and the second focal point, and a second opening is provided on the side of the optical cell unit on the side of the second focal point away from the first focal point, so as to retain an effective reflection area. The air chamber body and the substrate together form the reflective cavity.

[0008] In one embodiment, the inner wall of the air chamber body is mirror-plated with gold.

[0009] In one embodiment, the emission angle of the light source is 37°, and the reflection area of ​​the reflecting cavity is adapted to the emission range of the light source.

[0010] In one embodiment, support structures are respectively provided on both sides of the first opening of the air chamber body, and the support structures are connected to the substrate.

[0011] In one embodiment, the number of optical air chamber units is three, the first focal points of the three optical air chamber units are arranged to overlap, and the three optical air chamber units are arranged in an equilateral triangle with the first focal point as the center.

[0012] In one embodiment, the distance between the two support structures of the optical cell unit is less than or equal to 30. mm.

[0013] In one embodiment, the light sources of the three optical air chamber units are respectively provided with filters of different center wavelengths.

[0014] In one embodiment, the truncated ellipsoidal gas chamber for multi-channel non-dispersive infrared gas detection further includes an information processing module connected to the sensor for processing detection information.

[0015] The technical solution of this invention involves mounting multiple optical cell units on a substrate, with the first focal points of the multiple ellipsoidal arc-shaped sidewalls of the reflective cavities coinciding, and multiple second focal points arranged around the first focal point. A sensor is positioned at the first focal point, and a light source is positioned at the second focal point. In other words, the multiple optical cell units are arranged around the sensor, thereby unifying the optical emission paths of the multiple optical cell units, eliminating channel differences, reducing calibration difficulty, and improving detection efficiency. At the same time, a single sensor is shared, and the arrangement of multiple optical cell units around the unified sensor achieves compact integration of multiple channels. Furthermore, the sequential control of the optical cell units facilitates the orderly acquisition and detection of multi-channel gases, further improving detection efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a structural embodiment of a truncated ellipsoidal gas chamber for multi-channel non-dispersive infrared gas detection provided by the present invention. Figure 2 This is a schematic diagram of another embodiment of the truncated ellipsoidal gas chamber for multi-channel non-dispersive infrared gas detection provided by the present invention. Figure 3 This is a schematic diagram of the main structure of the gas chamber in one embodiment of the truncated ellipsoidal gas chamber for multi-channel non-dispersive infrared gas detection provided by the present invention. Figure 4 This is a cross-sectional view of an optical cell unit in one embodiment of a truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection provided by the present invention.

[0018] Explanation of icon numbers: 10. Substrate; 20. Optical air cell unit; 21. Reflection cavity; 22. Air cell body; 23. Bolt; 24. Support structure; 30. Sensor; 40. Light source.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] This invention proposes a truncated ellipsoidal gas chamber for multi-channel non-dispersive infrared gas detection.

[0024] Please see Figure 1 In one embodiment of the present invention, the truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection includes: Multiple optical air cell units 20 are disposed on the substrate 10, and each optical air cell unit 20 has a concave reflective cavity 21 formed therein. The sidewall of the reflective cavity 21 is an ellipsoidal arc surface, and the first focus and the second focus of the sidewall are both located on the surface of the substrate 10. The first focus of at least two ellipsoidal sidewalls of the reflective cavity 21 coincides. A sensor 30 is provided at the first focus, and a light source 40 is provided at the second focus. The light emitted by the light source 40 is reflected by the sidewall of the reflective cavity 21 to the sensor 30.

[0025] like Figure 1 As shown, substrate 10 is the support substrate for multiple optical air cell units 20.

[0026] It is understandable that the optical air chamber unit 20, sensor 30 and light source 40 are all mounted on the same plane of the substrate. By using a unified reference plane, the first focus and the second focus of the sidewall of the ellipsoidal arc surface reflection cavity 21 are ensured to be coplanar, thereby eliminating the alignment deviation caused by assembly.

[0027] like Figure 3 As shown, the optical air cell unit is concave to form a hollow ellipsoidal reflective cavity, and the inner wall of the cavity is a continuous ellipsoidal mirror arc surface.

[0028] It is understandable that the light source 40 is set at the second focal point and the sensor 30 is set at the first focal point. When the light source 40 emits light towards the inner wall of the reflective cavity 21, the light is reflected by the inner wall of the reflective cavity 21 and transmitted to the sensor 30. This serves as the first and second focal points of the fixed focal point, realizing the precise transmission of light and accurately converging it to the first focal point. This achieves lossless directional focusing and improves the accuracy of detection.

[0029] In one embodiment, the light source is an infrared light source, and the sensor can be an infrared photoelectric detector.

[0030] Furthermore, such as Figure 2 As shown, the first focal points of multiple optical cell units 20 coincide, that is, the second focal points of multiple optical cell units 20 are arranged around the same first focal point.

[0031] It is understandable that the light emitted by the light source 40 at the second focal point of the multiple optical air chamber units 20 can converge at the sensor at the first focal point after being reflected by their respective reflection cavities 21.

[0032] In this way, by controlling the operation of each light source 40 in sequence, the light sources 40 of each optical gas chamber unit 20 emit light in sequence, and the reflected light is received by the sensor at the first focal point, thereby facilitating the detection of different gases.

[0033] The technical solution of this invention involves placing multiple optical gas chamber units 20 on a substrate 10, with the first focal points of multiple ellipsoidal arc-shaped sidewall reflective cavities 21 coinciding, and multiple second focal points surrounding the first focal point. A sensor 30 is placed at the first focal point, and a light source 40 is placed at the second focal point. In other words, multiple optical gas chamber units 20 are arranged around the sensor 30, so that the light emission paths of multiple optical gas chamber units 20 are unified, thereby eliminating channel differences, reducing calibration difficulty, and improving detection efficiency. At the same time, they share a single sensor 30, and the arrangement of multiple optical gas chamber units 20 around the unified sensor 30 achieves compact integration of multiple channels. Furthermore, the sequential control of the optical gas chamber units 20 facilitates the orderly acquisition and detection of multi-channel gases, further improving detection efficiency.

[0034] In one embodiment, the first focal point is located outside the reflecting cavity 21, and the second focal point is located inside the reflecting cavity 21.

[0035] It should be noted that, in the optical properties of the ellipsoid, light rays emitted from any focus of the ellipsoid will converge at the other focus after being reflected by the sidewall of the ellipsoidal reflecting cavity 21.

[0036] Therefore, the sensor 30 and the light source 40 are respectively set at the first focal point and the second focal point, so that the light emitted by the light source 40 can be received by the sensor 30 after being reflected by the reflection cavity 21. While ensuring that the optical path remains constant, stable optical signal reception is achieved, thereby improving the sensor sensitivity.

[0037] like Figure 4 As shown, the light source 40 is disposed inside the reflective cavity 21, and the sensor 30 is externally disposed outside the reflective cavity 21.

[0038] It is understandable that the external sensor 30 eliminates the obstruction of the internal detection device in the reflective cavity 21, thereby improving the permeability of the reflective cavity 21 and increasing the gas flow cross-sectional area. This increases the gas replacement rate in the reflective cavity 21, shortens the gas concentration equilibrium time, and reduces the sensor's detection response time and improves detection efficiency after the light emitted by the light source is reflected by the inner wall of the reflective cavity 21 to the sensor.

[0039] Meanwhile, because the sensor 30 is external, multiple optical air chamber units 20 share the sensor 30.

[0040] It is understandable that the sensor 30 is external and not constrained by other reflective cavities 21. Relying on the inner wall of the ellipsoidal reflective cavity 21, multiple beams are converged to the same sensor, thereby achieving a multi-channel compact layout on a limited substrate surface, which is conducive to the miniaturization of the device.

[0041] Furthermore, the sensor 30 is externally mounted, which facilitates heat dissipation, reduces the sensor's operating temperature, and improves the stability and lifespan of the sensor during continuous monitoring.

[0042] In one embodiment, the optical air cell unit 20 includes an air cell body 22, which is a quarter-ellipsoidal structure. A first opening is provided on the side of the optical air cell unit 20 between the first focal point and the second focal point, and a second opening is provided on the side of the optical air cell unit 20 on the side of the second focal point away from the first focal point, so as to retain an effective reflection area. The air chamber body 22 and the substrate 10 together form the reflective cavity 21.

[0043] like Figure 3 As shown, a first opening and a second opening are respectively opened on the air chamber body 22 in the direction of the line connecting the first focus and the second focus.

[0044] It is understandable that the effective reflective arc surface required for the light source to be emitted and reflected to the sensor 30 is retained on the gas chamber body 22, while redundant ellipsoidal surfaces are eliminated. This achieves the functions of light path output, gas entry and exit, and assembly avoidance without damaging the ellipsoidal core focusing and reflecting area.

[0045] Meanwhile, the design of the first and second openings allows gas to quickly fill and enter and exit the reflective cavity 21, ensuring the gas replacement rate in the gas chamber.

[0046] The first opening is located between the first focal point and the second focal point, providing a dedicated light transmission channel for the reflected and converging beam. The light reflected from the inner wall of the ellipsoidal reflective cavity 21 can pass through the cavity to the sensor without obstruction, reducing light energy transmission loss and increasing the intensity of the light signal received by the sensor.

[0047] Furthermore, the quarter-ellipsoidal structure of the gas chamber body 22 eliminates redundant parts and forms multi-directional clearance space to facilitate the provision of workpieces for subsequent structural assembly. At the same time, multiple gas chamber bodies 22 are arranged around the first focus to facilitate the detection of various gases.

[0048] In one embodiment, the inner wall of the air chamber body 22 is mirror-plated with gold.

[0049] It is understandable that after surface treatment on the inner wall of the reflective cavity 21 of the air chamber body 22, a flat, smooth and uniform mirror surface is formed on the ellipsoidal arc-shaped sidewall, thereby suppressing diffuse reflection, improving the convergence of the reflected beam, and thus improving the accuracy of detection.

[0050] It should be noted that the main body of the air chamber 22 is made of aluminum alloy substrate.

[0051] Therefore, after the inner wall of the gas chamber body 22 is mirror-plated with gold, the oxidation and corrosion of the inner wall by the gas is effectively avoided, thus ensuring the flatness of the inner wall surface of the ellipsoidal reflective cavity 21 during long-term use, thereby ensuring the stability of the reflective performance and extending the service life.

[0052] In one embodiment, the emission angle of the light source 40 is 37°, and the reflection area of ​​the reflecting cavity 21 is adapted to the emission range of the light source.

[0053] Understandably, the emission angle of the light source 40 is limited to 37°, and the reflection area of ​​the reflection cavity 21 is adapted to the emission range of the light source. This allows the light emitted by the light source 40 to be reflected by the reflection area of ​​the reflection cavity 21 and converged at the sensor 30 at the first focal point. In this way, the quarter-ellipsoidal structure of the air chamber body 22 achieves total internal reflection of the light source while saving space, and also avoids light energy dissipation, thereby maximizing the intensity of the light signal received by the sensor and improving the accuracy of the detection results.

[0054] In one embodiment, support structures 24 are respectively provided on both sides of the first opening of the air chamber body 22, and are connected to the substrate 10 through the support structures.

[0055] like Figure 3As shown, support structures 24 are provided on both sides of the first opening of the air chamber body 22.

[0056] It is understandable that when the bottom surface of the support structure 24 is attached to the surface of the substrate 10, and the gas chamber body 22 is installed on the surface of the substrate 10, the bottom surface of the gas chamber body 22 is attached to the surface of the substrate 10, so that the reflective cavity 21 formed by this enclosure is relatively closed, and the gas enters and exits the reflective cavity 21 through the first opening and the second opening.

[0057] In one embodiment, a plurality of first connection holes are formed on the substrate 10, and a plurality of second connection holes are formed on the support structure 24. When the support structure 24 is disposed on the substrate 10, the first connection holes are directly opposite the second connection holes, and the support structure 24 is connected to the substrate 10 by bolts 23 or the like.

[0058] In another embodiment, the support structure is integrally formed with the air chamber body 22.

[0059] In one embodiment, there are three optical air chamber units 20, and the first focal points of the three optical air chamber units 20 are arranged to overlap. The three optical air chamber units are arranged in an equilateral triangle with the first focal point as the center.

[0060] like Figure 1 and Figure 2 As shown, there are three optical air cell units 20, and the three optical air cell units 20 are arranged in an equilateral triangle to form a multi-channel air cell structure of "single detector-multiple light source architecture".

[0061] It is understandable that the three optical chamber units 20 are arranged in an equilateral triangle so that the first focal points of the three ellipsoidal arc-shaped sidewalls coincide, thereby enabling the three optical chamber units to have independent optical path paths, and enabling the reflected light paths of the three optical chamber units to converge to the sensor at the first focal point, thus achieving compact convergence of multiple channels and realizing the detection of three gases at the same time.

[0062] Furthermore, the three optical gas chamber units 20 are arranged in an equilateral triangle with central symmetry so that the distance and relative angle between each optical gas chamber unit and the sensor 30 are the same. The optical path and light energy loss of the ellipsoidal reflective arc sidewalls of each channel are suppressed, thereby greatly reducing the calibration compensation parameters for multi-gas detection and simplifying the overall calibration process.

[0063] Meanwhile, the three optical air cell units 20 arranged around the equilateral triangle of the first focal point occupy a smaller substrate area, saving redundant space, improving space utilization, and making it easier to adapt to miniaturized sensing devices.

[0064] In one embodiment, the distance between the two support structures 24 of the optical cell unit 20 is less than or equal to 30. mm.

[0065] like Figure 4 As shown, the major axis of the arc-shaped sidewall of the ellipsoidal reflecting cavity 21 is 50mm, and the focal length is 30mm.

[0066] Therefore, when the emission angle of the light source is 37°, the side light emitted by the light source still illuminates the curved reflective surface, thus ensuring the rational and effective use of the reflective surface and avoiding the retention of excess reflective surface, which is conducive to the miniaturization of the detection equipment. Furthermore, the distance between the two support structures 24 is less than or equal to 30. mm, so that when the three air chamber bodies 22 are arranged around the overlapping first focal point, the support structure, work station, and light source assembly of adjacent optical air chamber units 20 will not interfere with each other.

[0067] In one embodiment, the light sources 40 of the three optical air chamber units 20 are respectively provided with filters of different center wavelengths.

[0068] It should be noted that the three optical gas chamber units 20 are used for the detection of acetylene, methane, and carbon dioxide, respectively.

[0069] To this end, corresponding dedicated narrowband filters were set on the three light sources 40, and the three filters were set with different center wavelengths to match the mid-infrared characteristic absorption peaks of acetylene (3.05μm), methane (3.31μm), and carbon dioxide (4.26μm).

[0070] Understandably, when a mixed gas exists, by using filters with different center wavelengths, the optical path in each optical cell unit 20 can only output the characteristic wavelength band of the corresponding gas, while the other gases do not have significant absorption in their respective wavelength bands. This allows an optical cell unit 20 to reflect only the concentration of the corresponding single gas. When detecting a mixed gas, the three optical cell units 20 are detected independently, thereby avoiding measurement errors caused by cross-absorption of gases and improving the accuracy of mixed gas detection.

[0071] In one embodiment, the truncated ellipsoidal gas chamber for multi-channel non-dispersive infrared gas detection further includes an information processing module connected to the sensor 30 for processing detection information.

[0072] The information processing module includes an infrared photodetector transimpedance amplifier circuit, an STM32 control and ADC acquisition module, and an OLED display module.

[0073] Understandably, the three light sources are lit sequentially in a time-division multiplexing manner under the control of the STM32, and the common detector 30 receives infrared signals from different truncated ellipsoidal channels in different time slices, thereby realizing the sequential acquisition and differentiation of multi-channel gas signals.

[0074] The above description is merely an exemplary embodiment of the present invention and does not limit the scope of protection of the present invention. Any equivalent structural transformations made based on the technical concept of the present invention and the contents of the specification and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present invention.

Claims

1. A truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection, characterized in that, include: An optical air cell unit, wherein multiple optical air cell units are disposed on a substrate, and a reflective cavity is formed in the recess of each optical air cell unit; The sidewall of the reflective cavity is an ellipsoidal arc surface, and the first focus and the second focus of the sidewall are both located on the surface of the substrate. The first focus of at least two of the ellipsoidal sidewalls of the reflective cavity coincides. A sensor is provided at the first focus and a light source is provided at the second focus. Light emitted by the light source is reflected by the sidewall of the reflective cavity to the sensor.

2. The truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection as described in claim 1, characterized in that, The first focal point is located outside the reflecting cavity, and the second focal point is located inside the reflecting cavity.

3. The truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection as described in claim 2, characterized in that, The optical cell unit includes a cell body, which is a quarter-ellipsoidal structure. A first opening is provided on the side of the optical cell unit between the first focal point and the second focal point. A second opening is provided on the side of the optical cell unit on the side of the second focal point away from the first focal point, so as to retain an effective reflection area. The air chamber body and the substrate together form the reflective cavity.

4. The truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection as described in claim 3, characterized in that, The inner wall of the air chamber body is mirror-plated with gold.

5. The truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection as described in claim 3, characterized in that, The emission angle of the light source is 37°, and the reflection area of ​​the reflection cavity is adapted to the emission range of the light source.

6. The truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection as described in claim 3, characterized in that, Support structures are respectively provided on both sides of the first opening of the air chamber body, and are connected to the substrate through the support structures.

7. The truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection as described in any one of claims 1 to 6, characterized in that, The optical air cell unit consists of three units, with their first focal points overlapping. The three units are arranged in an equilateral triangle around the first focal point.

8. The truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection as described in claim 7, characterized in that, The distance between the two supporting structures of the optical cell unit is less than or equal to 30. mm.

9. The truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection as described in claim 7, characterized in that, Each of the three optical air chamber units has a filter with a different center wavelength on its light source.

10. The truncated ellipsoidal gas cell for multi-channel non-dispersive infrared gas detection as described in any one of claims 1 to 6, characterized in that, The truncated ellipsoidal gas chamber for multi-channel non-dispersive infrared gas detection also includes an information processing module, which is connected to the sensor to process the detection information.

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