Photoacoustic sensor for detecting SO2F2 based on photoacoustic double-cavity detection method

Abstract

The invention relates to the technical field of gas sensors, in particular to a photoacoustic sensor for detecting SO2F2 based on a photoacoustic double-cavity detection method, which comprises an absorption assembly, a gas inlet assembly, a gas outlet assembly and a gas outlet assembly, the infrared light source is arranged on the surface of the absorption cell; gas is detected through light rays emitted by the infrared light source, interference of other gases can be reduced, the concentration of SO2F2 in various gases can be detected, meanwhile, due to the fact that the gases do not react with chemical substances, gas detection is faster and more stable, and the detection efficiency is improved. The SO2F2 gas in the gas can be detected for a long time.

Description

Technical Field

[0001] The present invention relates to the technical field of gas sensors, in particular to a photoacoustic sensor for detecting SO2F2 based on a photoacoustic double-cavity detection method. Background Art

[0002] In recent years, sulfuryl fluoride (SO2F2) has been widely used as a fumigant insecticide for homes, food and shipping containers, among other things; SO2F2 is neurotoxic and therefore poses a significant hazard to humans, for example to residents of treated homes or workers in the logistics industry, with an occupational exposure limit (OEL) of 5 ppm and a direct danger to life and health starting from 200 ppm.

[0003] In recent years, various sensors have been proposed; many of them are chemical sensors based on different material complexes. However, chemical sensors are designed to detect target gases in a low concentration range, but chemical sensors often have cross-sensitivity to other gases and do not have sufficient long-term stability. In addition to using chemical sensors to detect gases, optical sensors can usually be used to monitor gases, but optical sensors are more complex and more expensive. Therefore, a photoacoustic sensor for detecting SO2F2 based on a photoacoustic dual-cavity detection method is proposed to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method, which aims to solve the problem that the existing chemical sensors have difficulty in detecting the concentration of SO2F2 in mixed gases, resulting in the troublesome detection of SO2F2 gas.

[0005] The present invention proposes the following technical solution: a photoacoustic sensor for detecting SO2F2 based on a photoacoustic double-cavity detection method, which comprises

[0006] An absorption assembly, comprising an absorption tank and an air inlet arranged on the surface of the absorption tank; and

[0007] An infrared light source and a microphone are located in the absorption cell; wherein,

[0008] The gas to be detected can enter the absorption cell through the air inlet, and the microphone can monitor that the light emitted by the infrared light source is absorbed by the gas to be detected.

[0009] As a preferred embodiment of the photoacoustic sensor for detecting SO2F2 based on the photoacoustic double-cavity detection method of the present invention: an air outlet is provided on the surface of the absorption cell.

[0010] As a preferred embodiment of the photoacoustic sensor for detecting SO2F2 based on the photoacoustic double-cavity detection method of the present invention: a detection cell is fixed at one end of the absorption cell.

[0011] As a preferred embodiment of the photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method of the present invention: a window piece is fixed at the connection between the infrared light source and the detection cell.

[0012] As a preferred embodiment of the photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method of the present invention: the microphone is arranged on the surface of the detection cell.

[0013] As a preferred embodiment of the photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method of the present invention: the window piece is a transparent silicon piece.

[0014] As a preferred embodiment of the photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method of the present invention: the absorption cell and the detection cell are made of light-proof materials.

[0015] As a preferred embodiment of the photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method of the present invention: the air inlet and the air outlet are connected to the air inlet pipe and the air outlet pipe respectively.

[0016] As a preferred embodiment of the photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method of the present invention: the air inlet and the air outlet are symmetrically arranged relative to the absorption cell.

[0017] As a preferred embodiment of the photoacoustic sensor for detecting SO2F2 based on the photoacoustic double-cavity detection method of the present invention: the air inlet pipe and the air outlet pipe are made of light-proof material.

[0018] The beneficial effects of the present invention are as follows: by detecting gas through the light emitted by the infrared light source, the interference of other gases can be reduced, and the gas concentration of SO2F2 in multiple gases can be detected. At the same time, since the gas does not react with chemical substances, the gas detection is faster and more stable, and the SO2F2 gas in the gas can be detected for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments of the present invention. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Among them:

[0020] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0022] The terms used in the present invention are those commonly used in the art in view of the functions of the present invention, but these terms may vary according to the intentions of those skilled in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but rather as the meanings of the terms and the overall description of the present invention.

[0023] Example 1, reference Figure 1 This embodiment provides a photoacoustic sensor for detecting SO2F2 based on a photoacoustic dual-cavity detection method, comprising:

[0024] The absorption assembly 1 includes an absorption tank 11 and an air inlet 12 provided on the surface of the absorption tank 11; and

[0025] The infrared light source 2 and the microphone 5 are located in the absorption cell 11;

[0026] The gas to be detected can enter the absorption cell 11 through the air inlet 12 , and the microphone 5 can monitor that the light emitted by the infrared light source 2 is absorbed by the gas to be detected.

[0027] The infrared light source 2 emits infrared light of a specific wavelength corresponding to the SO2F2 gas, the specific wavelength being 7.7–8.1 μm or 10.5–12.2 μm, so that the infrared light can only be absorbed by the SO2F2 gas, and the other gases cannot absorb the infrared light. When the infrared light enters the detection cell 4, the light intensity is changed, thereby obtaining the concentration data of the SO2F2 gas inside the absorption cell 11.

[0028] Usage process: The gas to be tested enters the absorption cell 11 from the air inlet 12, and the infrared light source 2 emits infrared light of a specific wavelength corresponding to the SO2F2 gas, so that the infrared light energy is absorbed by the gas molecules and irradiates the gas to be tested. When the gas to be tested contains SO2F2 gas, the light is absorbed by the gas molecules, triggering a photoacoustic effect; the gas molecules expand due to heat and produce periodic pressure waves; which are detected by the microphone 5. The microphone 5 converts the pressure fluctuations into electrical signals, and the signal strength is proportional to the absorbed light intensity, thereby obtaining the SO2F2 gas concentration.

[0029] Example 2, reference Figure 1 , which is the second embodiment of the present invention, differs from the previous embodiment in that it further includes,

[0030] An air outlet 13 is provided on the surface of the absorption tank 11 .

[0031] The gas outlet 13 can discharge the gas inside the absorption cell 11, ensuring that the absorption cell 11 is not interfered by other gases before detection, thereby ensuring the accuracy of the detection result.

[0032] A detection cell 4 is fixed to one end of the absorption cell 11 .

[0033] A window 3 is provided between the detection cell 4 and the absorption cell 11 , so that the gas inside the absorption cell 11 cannot enter the detection cell 4 , while the light inside the absorption cell 11 can enter the detection cell 4 , thereby detecting the light intensity.

[0034] A window piece 3 is fixed at the connection between the infrared light source 2 and the detection cell 4 .

[0035] The window 3 can prevent the gases inside the absorption cell 11 and the detection cell 4 from flowing to each other, while light can pass through the window 3 and enter the detection cell 4 from the absorption cell 11, thereby ensuring the accuracy of the detection result.

[0036] The microphone 5 is arranged on the surface of the detection cell 4 .

[0037] The microphone 5 can detect the periodic pressure waves generated by the thermal expansion of gas molecules, thereby obtaining the light intensity data inside the detection cell 4 and thus obtaining the gas data inside the absorption cell 11 .

[0038] The window piece 3 is a transparent silicon piece.

[0039] Transparent silicon wafers have high clarity, reducing brightness loss caused by light passing through the wafer. At the same time, the thermal deformation of the silicon wafer is small. After the gas expands due to heat, the heat is transferred to the silicon wafer, reducing the impact of the silicon wafer expansion on the periodic pressure waves generated by the thermal expansion of the gas.

[0040] The air inlet 12 and the air outlet 13 are connected to the air inlet pipe and the air outlet pipe respectively.

[0041] The air inlet and outlet pipes can ensure smooth air inlet and outlet, ensuring that the gas can stay stably inside the absorption tank 11 during the detection phase.

[0042] The air inlet 12 and the air outlet 13 are symmetrically arranged relative to the absorption tank 11 .

[0043] The gas outlet 13 is arranged corresponding to the gas inlet 12 to facilitate the normal discharge of gas, reduce the residual gas inside the absorption cell 11, and ensure the accuracy of subsequent detection.

[0044] Usage process: The infrared light source 2 emits infrared light of a specific wavelength, covering the absorption band of the target gas and its alternative gas (such as R227ea); the gas to be measured enters the absorption cell 11 through the air inlet 12 and interacts with the infrared light in the absorption cell 11; the target gas molecules absorb light energy of a specific wavelength, causing the light intensity to attenuate, and the light is absorbed by the gas molecules, triggering a photoacoustic effect; the gas molecules expand due to heat and produce periodic pressure waves; which are detected by the microphone 5, and the microphone 5 converts the pressure fluctuations into electrical signals. The signal strength is proportional to the absorbed light intensity, thereby obtaining the gas concentration of SO2F2.

[0045] Example 3, reference Figure 1 , which is the third embodiment of the present invention, is different from the previous embodiment in that it further includes:

[0046] The absorption cell 11 and the detection cell 4 are made of light-proof materials.

[0047] The absorption cell 11 and the detection cell 4 are made of light-proof materials to reduce the influence of external light, and at the same time prevent the infrared light of the infrared light source from being transmitted to the external environment, which may cause errors in the detection structure.

[0048] The air inlet and outlet pipes are made of light-proof materials.

[0049] The air inlet pipe and the air outlet pipe are directly connected to the air inlet 12 and the air outlet 13, and the use of light-proof materials can reduce the influence of external light as much as possible.

[0050] Usage process: The absorption pool 11 and the detection pool 4 are made of light-proof materials to reduce the influence of external light, and at the same time prevent the infrared light of the infrared light source from being transmitted to the external environment, resulting in errors in the detection structure. The air inlet pipe and the air outlet pipe are directly connected to the air inlet 12 and the air outlet 13. The use of light-proof materials can minimize the influence of external light.

[0051] Working principle: The infrared light source 2 emits infrared light of a specific wavelength, covering the absorption band of the target gas and its alternative gas (such as R227ea); the gas to be measured enters the absorption cell 11 through the air inlet 12, and interacts with the infrared light in the absorption cell 11; the target gas molecules absorb the light energy of a specific wavelength, resulting in the attenuation of the light intensity, and the light passes through the window 3 along the absorption cell 11 and enters the detection cell 4. The detection cell 4 is filled with pure target gas or alternative gas (such as R227ea), and its absorption spectrum partially overlaps with that of SO2F2; the light is absorbed by the gas molecules in the detection cell 4, triggering a photoacoustic effect; the gas molecules expand due to heat and produce periodic pressure waves; which are detected by the microphone 5. The microphone 5 integrated in the detection cell 4 converts the pressure fluctuations into electrical signals, and the signal strength is proportional to the absorbed light intensity, thereby obtaining the gas concentration of SO2F2, and the detected gas is discharged from the air outlet 13.

[0052] Finally, it should be pointed out that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways without departing from the scope of the present invention.

Claims

1. A photoacoustic sensor for detecting SO2F2 based on a photoacoustic dual-cavity detection method, characterized in that: include, An absorption assembly (1) comprises an absorption tank (11) and an air inlet (12) arranged on the surface of the absorption tank (11); and An infrared light source (2) and a microphone (5) are located in the absorption cell (11); wherein, The gas to be detected can enter the absorption cell (11) through the air inlet (12), and the microphone (5) can monitor that the light emitted by the infrared light source (2) is absorbed by the gas to be detected.

2. The photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method according to claim 1, characterized in that: An air outlet (13) is provided on the surface of the absorption tank (11).

3. The photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method according to claim 2, characterized in that: A detection cell (4) is fixed to one end of the absorption cell (11).

4. The photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method according to claim 3, characterized in that: A window piece (3) is fixed at the connection between the infrared light source (2) and the detection cell (4).

5. The photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method according to claim 4, characterized in that: The microphone (5) is arranged on the surface of the detection pool (4).

6. The photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method according to claim 5, characterized in that: The window piece (3) is a transparent silicon piece.

7. The photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method according to claim 6, characterized in that: The absorption cell (11) and the detection cell (4) are made of light-proof materials.

8. The photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method according to claim 7, characterized in that: The air inlet (12) and the air outlet (13) are connected to the air inlet pipe and the air outlet pipe respectively.

9. The photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method according to claim 8, characterized in that: The air inlet (12) and the air outlet (13) are symmetrically arranged relative to the absorption tank (11).

10. The photoacoustic sensor for detecting SO2F2 based on the photoacoustic dual-cavity detection method according to claim 9, characterized in that: The air inlet pipe and the air outlet pipe are made of light-proof materials.

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