Gas sensor

Abstract

The utility model relates to a gas sensor. The gas sensor comprises a driving plate, a shell, a transmitting assembly and a signal processing part, the shell is provided with an air inlet channel, the shell is installed on the driving plate, the shell and the driving plate jointly form a photoacoustic cell, and the photoacoustic cell is communicated with the air inlet channel. The emission assembly is arranged in the photoacoustic cell and used for emitting light into the photoacoustic cell so as to excite gas in the photoacoustic cell. The signal processing part is arranged in the photoacoustic cell, and the signal processing part is used for receiving a signal from the transmitting assembly and outputting a detection result. According to the gas sensor provided by the embodiment of the invention, the transmitting assembly and the signal processing part are arranged in the gas sensor, so that the gas to be detected can be detected, the internal structure of the gas sensor is simplified, the manufacturing difficulty of the gas sensor is reduced, and the manufacturing time of the gas sensor is saved.

Description

Technical Field

[0001] The present application relates to the field of detection technology, and in particular to a gas sensor. Background Art

[0002] Gas sensors are currently a widely used type of sensor, among which gas sensors using the principle of photoacoustic spectroscopy are favored by users due to their good detection sensitivity. Currently, gas sensors using photoacoustic spectroscopy have a complex internal structure, which requires users to spend a lot of time to prepare gas sensors. Utility Model Content

[0003] Based on this, it is necessary to provide a sensor with a simple internal structure that can be prepared in a shorter time to address the problem that the gas sensor has a complex internal structure and takes a long time to prepare.

[0004] A gas sensor, comprising:

[0005] Driver board;

[0006] A housing having an air inlet passage, wherein the housing is mounted on a driving plate and forms a photoacoustic cell together with the driving plate, and the photoacoustic cell is in communication with the air inlet passage;

[0007] An emission component is disposed in the photoacoustic cell and is used to emit light into the photoacoustic cell to excite the gas in the photoacoustic cell;

[0008] The signal processing component is arranged in the photoacoustic cell, and is used for receiving the signal from the transmitting component and outputting the detection result.

[0009] In one of the embodiments, the emission component includes a filter and a light source, the light source is connected to the driving board, and the filter is located on a side of the light source away from the driving board and is arranged toward a light outlet of the light source.

[0010] In one of the embodiments, the filter element is detachably mounted on a side of the light source facing away from the driving board.

[0011] In one embodiment, the filter is bonded to the light source.

[0012] In one embodiment, the filter element is a 4.26 μm filter.

[0013] In one of the embodiments, the gas sensor further includes a waterproof and breathable membrane, which is detachably mounted on the housing and covers the air inlet passage.

[0014] In one embodiment, the waterproof breathable membrane is bonded to the shell.

[0015] In one of the embodiments, the waterproof and breathable membrane is disposed on a surface of the housing facing away from the driving plate.

[0016] In one of the embodiments, the housing and the driving plate are sealed together.

[0017] In one of the embodiments, the outer surfaces of the shell and the drive plate are both covered with an anti-corrosion film.

[0018] The above-mentioned gas sensor is provided with a transmitting component and a signal processing component inside thereof, so as to detect the gas to be detected, thereby simplifying the internal structure of the gas sensor, reducing the manufacturing difficulty of the gas sensor, and saving the manufacturing time of the gas sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the internal structure of a gas sensor is provided for some embodiments of the present application.

[0020] Figure 2 An exploded diagram of a gas sensor is provided for some embodiments of the present application.

[0021] Figure 3 A perspective view of a gas sensor is provided for some embodiments of the present application.

[0022] Description of reference numerals:

[0023] 10. driving board; 20. housing; 21. air inlet channel; 30. photoacoustic cell; 40. transmitting assembly; 41. optical filter; 42. light source; 50. signal processing unit; 60. waterproof breathable membrane; 100. gas sensor. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0025] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0026] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0027] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0028] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0029] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0030] The working principle of the photoacoustic spectroscopy gas sensor is as follows: when a beam of modulated or pulsed laser is irradiated onto the sample, the absorber inside the sample undergoes local thermal expansion after absorbing the light energy, thereby generating mechanical waves and forming outward mechanical waves, which are easily received by the detector placed around the tissue. As the wavelength of the incident laser continues to change, the strength of the signal received by the detector will also change accordingly with the absorption spectrum of the absorber, thereby obtaining the corresponding signal spectrum.

[0031] When a substance absorbs light and is excited, it can return to its initial state through radiative transition or non-radiative transition. The former process produces fluorescence or phosphorescence, while the latter process produces heat. Because the intensity of the absorbed light changes periodically, the pressure fluctuation in the container is also periodic. When the sample is a gas or liquid, it is itself a pressure medium. The electrical signal obtained by synchronously amplifying the mechanical wave sensed by the element is an optical signal. If the signal is recorded as a function of the frequency of the incident light, a spectrum can be obtained.

[0032] The photoacoustic spectroscopy gas sensor is used to detect carbon dioxide in the air, and the detection data obtained has high accuracy. Since the structure of the photoacoustic spectroscopy gas sensor is complex and it takes a lot of time to prepare, there is an urgent need for a photoacoustic spectroscopy gas sensor that is easy to prepare.

[0033] See also Figures 1 to 3 Some embodiments of the present application provide a gas sensor 100. The gas sensor 100 includes a driving board 10, a shell 20, a transmitting assembly 40, and a signal processing component 50. The shell 20 has an air inlet channel 21, the shell 20 is mounted on the driving board 10, and together with the driving board 10, forms a photoacoustic pool 30, and the photoacoustic pool 30 is connected to the air inlet channel 21. The transmitting assembly 40 is disposed in the photoacoustic pool 30, and is used to emit light into the photoacoustic pool 30 to excite the gas in the photoacoustic pool 30. The signal processing component 50 is disposed in the photoacoustic pool 30, and the signal processing component 50 is used to receive a signal from the transmitting assembly 40 and output a detection result.

[0034] The driving board 10 may be a PCB board, and a circuit may be arranged on the PCB board. The photoacoustic cell 30 may be understood as a receiving space formed by the housing 20 and the driving board 10 .

[0035] The signal processing unit 50 is used to collect the thermoacoustic waves in the photoacoustic pool 30. The signal processing unit 50 can be a micro-electromechanical system microphone, i.e., a MEMS microphone. A MEMS microphone can be understood as a capacitor integrated on a micro silicon wafer, which can be manufactured using a surface mount process, can withstand very high reflow soldering temperatures, and is easily integrated with CMOS processes and other audio circuits. MEMS microphones have improved noise elimination performance and electromagnetic interference suppression capabilities.

[0036] During use, the gas sensor 100 can be placed in the area to be detected, and the air in the area to be detected can enter the photoacoustic cell 30 in the gas sensor 100 through the air inlet channel 21 on the housing 20. At this time, the transmitting component 40 located in the photoacoustic cell 30 can emit light in a specific wavelength band into the photoacoustic cell 30. When the gas molecules entering the photoacoustic cell 30 can absorb the light in the wavelength band, the gas molecules can be excited to expand and generate a sound wave. The sound wave can be received by the signal processing component 50 and converted into a digital signal output. In this way, the concentration of the measured gas can be calculated based on the intensity of the output sound wave.

[0037] In this way, by setting the transmitting component 40 and the signal processing component 50 inside the gas sensor 100, the gas to be detected can be detected, which simplifies the internal structure of the gas sensor 100, reduces the manufacturing difficulty of the gas sensor 100, and saves the manufacturing time of the gas sensor 100.

[0038] See also Figure 2 In some embodiments, the emitting component 40 includes a filter 41 and a light source 42 . The light source 42 is connected to the driving board 10 . The filter 41 is located on a side of the light source 42 away from the driving board 10 and is arranged toward a light outlet of the light source 42 .

[0039] The light source 42 may be a MEMS infrared light source 42, which is a new type of infrared light source 42, which is composed of a micro-electromechanical system and an infrared luminescent material. The working principle of the MEMS infrared light source 42 is to control the luminous intensity and spectrum of the infrared luminescent material by controlling the temperature of the infrared luminescent material.

[0040] The simulation method of the MEMS infrared light source 42 mainly includes optical simulation and thermal simulation. Optical simulation studies the optical performance of the MEMS infrared light source 42 by simulating the propagation and imaging process of the optical system. Thermal snow simulation studies the thermal performance of the MEMS infrared light source 42 by simulating the heat conduction process of the infrared luminescent material.

[0041] When the transmitting assembly 40 is in operation, the light source 42 emitted by the MEMS infrared light source 42 can pass through the filter 41 and form a light of a specific wavelength. At the same time, the modulated MEMS infrared light source 42 can quickly and continuously provide energy to the gas in the photoacoustic cell 30 with light pulses of precise wavelength, so that the gas can be heated and cooled, causing the gas to expand and contract due to heat, thereby generating thermoacoustic pressure.

[0042] It should be noted that the sound waves and resonant waves in the photoacoustic cell 30 can form standing waves, which can play a role in resonance amplification. The frequency of the modulated light source 42 matches (coincides with) the intrinsic frequency in the chamber to form resonance. The photoacoustic signal will be amplified after resonance. After the amplified photoacoustic signal is output, it is received and analyzed by the analysis device. Among them, the high sensitivity of the resonant photoacoustic cavity plays a key role in the stable output of the photoacoustic signal. The larger the photoacoustic signal in the resonance process, the higher the gas concentration value in the cavity, and the signal amplitude is proportional to the gas concentration.

[0043] In this way, the matched MEMS infrared light source 42 and the filter 41 are used to excite the gas molecules of the gas to be detected entering the photoacoustic cell 30, and the concentration of the gas within the absorption specific wavelength can be detected to improve the accuracy of the detection.

[0044] Specifically, the filter 41 is a 4.26 μm filter. Since the wavelength range of carbon dioxide mainly absorbs is 4.2 μm to 4.4 μm, the filter 41 is set as a 4.26 μm filter, so that the light passing through the filter 41 can form a light with a specific wavelength of 4.26 μm and a fixed frequency of 42.5 Hz to detect the concentration of carbon dioxide in the gas to be detected, thereby improving the accuracy of the obtained detection data.

[0045] It is understandable that when the wavelength of the light filtered by the filter 41 changes, it can be used to detect the concentration of the corresponding gas.

[0046] Furthermore, in some embodiments, the filter 41 is detachably mounted on a side of the light source 42 facing away from the driving board 10 .

[0047] The filter 41 can be installed on the light source 42 by, but not limited to, snap-fitting or other methods. The filter 41 and the light source 42 are arranged to be detachable, and when at least one of the filter 41 and the light source 42 is damaged, the damaged part can be replaced with a new part. This is equivalent to replacing the filter 41 and the light source 42 together, and only replacing the damaged part can reduce the maintenance cost of the gas sensor 100.

[0048] Furthermore, in some embodiments, the filter 41 is bonded to the light source 42. In this way, the assembly method of the filter 41 is further simplified and the assembly speed of the filter 41 is accelerated.

[0049] like Figure 3 As shown, in some embodiments, the gas sensor 100 further includes a waterproof and breathable membrane 60 , which is detachably mounted on the housing 20 and covers the air inlet passage 21 .

[0050] When the gas sensor 100 is used, the gas to be detected can enter the photoacoustic cell 30 through the air inlet channel 21. Because the air inlet channel 21 is provided with a waterproof breathable membrane 60, impurities such as dust carried by the gas to be detected can be blocked by the waterproof breathable membrane 60, which can reduce the dust and other impurities carried by the gas to be detected from entering the photoacoustic cell 30, thereby adversely affecting the components arranged in the photoacoustic cell 30 and even affecting the detection results. Such a setting can not only improve the accuracy of the detection results, but also protect the components arranged in the photoacoustic cell 30, so as to extend the service life of the gas sensor 100.

[0051] Specifically, in some embodiments, the waterproof breathable membrane 60 is bonded to the housing 20. When the waterproof breathable membrane 60 needs to be replaced, it is convenient for the user to replace the waterproof breathable membrane 60, thereby reducing the difficulty of disassembling and assembling the waterproof breathable membrane 60.

[0052] More specifically, if Figure 3 As shown, in some embodiments, the waterproof breathable membrane 60 is disposed on the surface of the housing 20 away from the driving board 10. Since one side of the waterproof breathable membrane 60 is disposed toward the outside, when the user disassembles and assembles the waterproof breathable membrane 60, it is not necessary to remove the housing 20 from the driving board 10, and the waterproof breathable membrane 60 can be directly removed from the housing 20, which further simplifies the disassembly and assembly steps of the waterproof breathable membrane 60.

[0053] In some embodiments, the housing 20 and the drive plate 10 are sealed and connected. Exemplarily, the housing 20 and the drive plate 10 can be fixed using epoxy resin. Epoxy resin itself has the advantages of strong adhesion, high strength and good corrosion resistance. In this way, the connection between the housing 20 and the drive plate 10 can be sealed, reducing the probability that the external gas or liquid enters the photoacoustic cell 30 through the connection between the housing 20 and the drive plate 10 and adversely affects the components in the photoacoustic cell 30, thereby affecting the accuracy of the detection data.

[0054] Of course, the connection between the housing 20 and the driving board 10 can also be reinforced to improve the connection strength between the two. When the gas sensor 100 is impacted by external force, the probability of the housing 20 and the driving board 10 being separated, thereby rendering the gas sensor 100 unusable, is reduced.

[0055] In some embodiments, the outer surfaces of the housing 20 and the driving plate 10 are covered with an anti-corrosion film. When the housing 20 and / or the driving plate 10 are in contact with corrosive liquids, the probability that the housing 20 and / or the driving plate 10 are corroded and the gas sensor 100 cannot be used normally can be reduced, and the service life of the gas sensor 100 can be extended.

[0056] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0057] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A gas sensor, characterized in that: include: A driving plate (10); A housing (20) having an air inlet passage (21), wherein the housing (20) is mounted on a driving plate (10) and forms a photoacoustic pool (30) together with the driving plate (10), wherein the photoacoustic pool (30) is in communication with the air inlet passage (21); An emission component (40) is disposed in the photoacoustic cell (30) and is used to emit light into the photoacoustic cell (30) to excite the gas in the photoacoustic cell (30); A signal processing component (50) is disposed in the photoacoustic cell (30), and the signal processing component (50) is used to receive a signal from the transmitting component (40) and output a detection result.

2. The gas sensor according to claim 1, characterized in that The emission component (40) comprises a filter (41) and a light source (42); the light source (42) is connected to the driving board (10); the filter (41) is located on a side of the light source (42) away from the driving board (10) and is arranged toward a light outlet of the light source (42).

3. The gas sensor according to claim 2, characterized in that: The filter element (41) is detachably mounted on a side of the light source (42) facing away from the driving plate (10).

4. The gas sensor according to claim 3, characterized in that: The optical filter (41) is bonded to the light source (42).

5. The gas sensor according to claim 2, characterized in that: The optical filter (41) is a 4.26 μm filter.

6. The gas sensor according to claim 1, characterized in that The gas sensor (100) further comprises a waterproof and breathable membrane (60), wherein the waterproof and breathable membrane (60) is detachably mounted on the housing (20) and covers the air inlet passage (21).

7. The gas sensor according to claim 6, characterized in that: The waterproof and breathable membrane (60) is bonded to the housing (20).

8. The gas sensor according to claim 6, characterized in that: The waterproof and breathable membrane (60) is arranged on a surface of the housing (20) facing away from the driving plate (10).

9. The gas sensor according to claim 1, characterized in that: The housing (20) and the driving plate (10) are sealed and connected.

10. The gas sensor according to claim 1, characterized in that The outer surfaces of the housing (20) and the driving plate (10) are both covered with an anti-corrosion film.

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