A hydrogen detection device system and method based on photoacoustic effect

Abstract

The present invention provides a hydrogen detection device based on photoacoustic effect, comprising a body; a cavity is provided in the body, and an air inlet, an air outlet, a laser incident port and a microphone connected to the cavity are provided on the body; the air inlet and the air outlet are used to pass the gas to be tested into the cavity; the laser incident port is sealed with a lens for laser entry; a diaphragm is provided in the cavity, and the diaphragm includes a germanium sheet that is deformed when irradiated with laser, and a palladium film that is arranged on the germanium sheet and expands after absorbing hydrogen; the microphone is used to detect the sound waves generated by the deformation of the diaphragm, and convert them into analog signals for output. The present invention adopts the photoacoustic effect of the germanium sheet and superimposes the gas sensitive characteristics of the palladium film, so that the photoacoustic spectroscopy technology can be used to detect hydrogen, filling the gap in this technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of photoacoustic spectroscopy and gas detection, and in particular relates to a hydrogen detection device system and method based on photoacoustic effect. Background Art

[0002] In recent years, with the rapid development of the optical communication industry, the cost of the entire optical device has been reduced, making the industrialization of photoacoustic spectroscopy technology better and better. Photoacoustic spectroscopy is a detection technology based on the principle of gas infrared absorption without background signals, which has the advantages of high sensitivity and short detection time. For example, laser photoacoustic spectroscopy is applied to transformer status monitoring by measuring the concentration of gases such as acetylene, ethane, and methane in the transformer. However, hydrogen does not absorb infrared light, which makes it impossible to detect it with existing photoacoustic spectroscopy technology. Therefore, photoacoustic spectroscopy technology is limited. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a hydrogen detection device system and method based on the photoacoustic effect to fill the gap in this technology.

[0004] The technical solution adopted by the present invention to solve the above technical problems is: a hydrogen detection device based on photoacoustic effect, the device comprises a body; a cavity is provided in the body, and an air inlet, an air outlet, a laser incident port and a microphone connected to the cavity are provided on the body;

[0005] The gas inlet and the gas outlet are used to introduce the gas to be tested into the cavity;

[0006] The laser incident port is sealed with a lens for laser entry;

[0007] A diaphragm is arranged in the cavity, and the diaphragm includes a germanium sheet that is deformed when irradiated by laser, and a palladium film that is arranged on the germanium sheet and expands after absorbing hydrogen;

[0008] The microphone is used to detect the sound waves generated by the deformation of the diaphragm and convert them into analog signal output.

[0009] According to the above device, the laser incident port is arranged at the bottom of the body, the diaphragm is arranged just above the lens, and the microphone is arranged just above the diaphragm.

[0010] According to the above device, the air inlet and the air outlet are arranged on the side of the body.

[0011] According to the above device, in the cavity, film supports are provided on both sides of the lens, and the two ends of the germanium sheet are fixed on the film supports.

[0012] According to the above device, the thickness of the germanium sheet is in the micrometer range, and the eigenfrequency is lower than 20kHz.

[0013] A hydrogen detection system based on photoacoustic effect, the system comprises the device, a laser and a data processing control unit; wherein the data processing control unit controls the emission period of the laser, thereby modulating the frequency of the sound waves emitted by the germanium sheet and the palladium film, and the data processing control unit receives the analog signal output by the microphone and analyzes whether the gas to be detected contains hydrogen.

[0014] According to the above system, the data processing control unit includes a modulator connected to the laser, a signal processor connected to the microphone, and a data processor connected to the signal processor; wherein the modulator is used to modulate the emission period of the laser, the signal processor is used to shape the analog signal of the microphone, and the data processor is used to perform data calculation to determine whether the gas to be tested contains hydrogen.

[0015] According to the above system, the laser is a near-infrared DFB semiconductor laser that can be directly tuned.

[0016] A gas detection method implemented by using the hydrogen detection system based on photoacoustic effect, the method comprising:

[0017] When there is no hydrogen, by modulating a laser of a certain wavelength, a periodically changing output light is generated, thereby modulating the deformation of the germanium sheet and further generating sound waves; by scanning the modulation frequency, the intrinsic frequency spectrum of the germanium sheet is obtained;

[0018] When detecting gas, the palladium film expands after absorbing hydrogen, changing the intrinsic frequency spectrum of the germanium sheet. By analyzing the sound waves received by the microphone and comparing them with the sound waves when there is no hydrogen, it is possible to analyze whether the gas to be tested contains hydrogen.

[0019] The beneficial effect of the present invention is that by adopting the photoacoustic effect of the germanium sheet and superimposing the gas sensitive characteristics of the palladium film, the photoacoustic spectroscopy technology can be used to detect hydrogen, thus filling the gap in this technology. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0021] Figure 2 Schematic diagram of the detection principle of an embodiment of the present invention.

[0022] In the figure: 1-body, 2-laser, 3-lens, 4-air inlet, 5-air outlet, 6-microphone, 7-germanium sheet, 8-palladium membrane, 9-membrane support. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with specific examples and drawings.

[0024] This embodiment provides a hydrogen detection device based on the photoacoustic effect. Figure 1 and Figure 2 As shown, the device includes a body 1; a cavity is provided in the body 1, and an air inlet 4, an air outlet 5, a laser incident port and a microphone 6 connected to the cavity are provided on the body 1; the air inlet 4 and the air outlet 5 are used to introduce the gas to be measured into the cavity; the laser incident port is sealed with a lens 3 for laser entry; a diaphragm is provided in the cavity, and the diaphragm includes a germanium sheet 7 for being deformed by laser irradiation, and a palladium film 8 arranged on the germanium sheet 7 for absorbing hydrogen and then expanding; the microphone 6 is used to detect the sound waves generated by the deformation of the diaphragm and convert them into analog signals for output.

[0025] In this embodiment, the laser incident port is arranged at the bottom of the body 1, the germanium sheet 7 and the palladium film 8 are arranged just above the lens 3, and the microphone 6 is arranged just above the palladium film 8. The air inlet 4 and the air outlet 5 are arranged on the side of the body 1.

[0026] In the cavity, film supports 9 are provided on both sides of the lens 3 , and two ends of the germanium sheet 7 are fixed on the film supports 9 .

[0027] The germanium sheet 7 has a thickness of micrometer order and an eigenfrequency lower than 20 kHz. Then a palladium film 8 is plated on the germanium sheet 7 .

[0028] This embodiment also provides a hydrogen detection system based on the photoacoustic effect, comprising the above-mentioned device, a laser 2 and a data processing control unit; wherein the data processing control unit controls the emission period of the laser 2, thereby modulating the frequency of the sound waves emitted by the germanium sheet 7 and the palladium film 8, and the data processing control unit receives the analog signal output by the microphone 6 and analyzes whether the gas to be tested contains hydrogen.

[0029] The data processing control unit includes a modulator connected to the laser 2, a signal processor connected to the microphone 6, and a data processor connected to the signal processor. The modulator is used to modulate the emission period of the laser 2, the signal processor is used to shape the analog signal of the microphone 6, and the data processor is used to perform data calculation to determine whether the gas to be tested contains hydrogen.

[0030] In this embodiment, the laser 2 is a directly tunable near-infrared DFB semiconductor laser.

[0031] A hydrogen detection method implemented by using the hydrogen detection system based on photoacoustic effect, the method comprises: when there is no hydrogen, by modulating a laser of a certain wavelength, a periodically changing output light is generated, thereby modulating the deformation of the germanium sheet 7, and further generating sound waves; by scanning the modulation frequency, the intrinsic frequency spectrum of the germanium sheet is obtained; when detecting gas, the palladium film 8 expands after absorbing hydrogen, changing the intrinsic frequency spectrum of the film, and by analyzing the sound waves received by the microphone 6 and comparing them with the sound waves when there is no hydrogen, it is analyzed whether the gas to be tested contains hydrogen.

[0032] After the germanium sheet 7 absorbs the 1550nm laser, its temperature rises and deformation occurs. By modulating the laser, a periodically changing output light is generated, thereby modulating the deformation of the germanium sheet 7 and further generating sound waves. By scanning the modulation frequency, the response spectrum of the germanium sheet 7 is plotted. When the palladium film 8 absorbs hydrogen, it expands, changing the intrinsic frequency spectrum of the germanium sheet 7 and the palladium film 8 as a whole. By analyzing the spectrum of the sound signal received by the microphone 6, it is analyzed whether the gas to be tested contains hydrogen.

[0033] The idea of ​​the present invention is to combine the palladium film 8 with the photoacoustic effect to realize the detection of hydrogen by photoacoustic spectroscopy. Compared with the fiber grating coating sensing structure and the fiber interference structure, the present invention has a smaller volume and higher working environment redundancy. The present invention also solves the problem of gas detection with no or weak absorption of infrared light using photoacoustic spectroscopy.

[0034] The above embodiments are only used to illustrate the design ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design ideas disclosed by the present invention are within the protection scope of the present invention.

Claims

1. A hydrogen detection device based on photoacoustic effect, characterized in that: The device comprises a body; a cavity is arranged in the body, and an air inlet, an air outlet, a laser incident port and a microphone which are connected to the cavity are arranged on the body; The gas inlet and the gas outlet are used to introduce the gas to be tested into the cavity; The laser incident port is sealed with a lens for laser entry; A diaphragm is arranged in the cavity, and the diaphragm includes a germanium sheet for deforming when irradiated by laser, and a palladium film arranged on the germanium sheet for expanding after absorbing hydrogen; The microphone is used to detect the sound waves generated by the deformation of the diaphragm and convert them into analog signal output.

2. The device according to claim 1, characterized in that: The laser incident port is arranged at the bottom of the body, the diaphragm is arranged just above the lens, and the microphone is arranged just above the diaphragm.

3. The device according to claim 2, characterized in that: The air inlet and the air outlet are arranged on the side of the main body.

4. The device according to claim 2, characterized in that: In the cavity, film supports are arranged on both sides of the lens, and the two ends of the germanium sheet are fixed on the film supports.

5. The device according to claim 1, characterized in that: The thickness of the germanium sheet is in the micrometer range, and the intrinsic frequency is lower than 20kHz.

6. A hydrogen detection system based on photoacoustic effect, characterized in that: The system comprises the device as described in any one of claims 1 to 5, and also comprises a laser and a data processing control unit; wherein the data processing control unit controls the emission period of the laser, thereby modulating the frequency of the sound waves emitted by the germanium sheet and the palladium film, and the data processing control unit receives the analog signal output by the microphone and analyzes whether the gas to be tested contains hydrogen.

7. The system according to claim 6, characterized in that: The data processing control unit includes a modulator connected to the laser, a signal processor connected to the microphone, and a data processor connected to the signal processor; wherein the modulator is used to modulate the emission period of the laser, the signal processor is used to shape the analog signal of the microphone, and the data processor is used to perform data calculation to determine whether the gas to be tested contains hydrogen.

8. The system according to claim 6, characterized in that: The laser is a near-infrared DFB semiconductor laser which can be directly tuned.

9. A method for hydrogen detection using the hydrogen detection system based on photoacoustic effect as claimed in any one of claims 6 to 8, the method comprising: When there is no hydrogen, by modulating a laser of a certain wavelength, a periodically changing output light is generated, thereby modulating the deformation of the germanium sheet and further generating sound waves; by scanning the modulation frequency, the intrinsic frequency spectrum of the germanium sheet is obtained; When detecting gas, the palladium film expands after absorbing hydrogen, changing the intrinsic frequency spectrum of the germanium sheet. By analyzing the sound waves received by the microphone and comparing them with the sound waves when there is no hydrogen, it is possible to analyze whether the gas to be tested contains hydrogen.

10. The method according to claim 9, characterized in that: The certain wavelength is an infrared wavelength.

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