Multi-cavity gas detection device and method

Abstract

The invention discloses a multi-cavity gas detection device and method, and relates to the technical field of gas detection.The device comprises a photoacoustic cell which comprises a plurality of coupled acoustic resonant cavities and is used for bearing to-be-detected gas; the multiband laser output unit is arranged on one side of the photoacoustic cell and is used for emitting a plurality of lasers with specific wavelengths; the sensors are used for detecting photoacoustic signals in the corresponding acoustic resonant cavities; and the function generator is used for controlling the waveform signal of the laser output by the multiband laser output unit. Through the multi-cavity coupling design, synchronous detection of decomposed multi-component gas is realized, and the equipment cost and the maintenance complexity are reduced; a sensor is combined with a photoacoustic effect, so that the signal intensity and the detection precision are remarkably improved; an innovative wavelength feedback control system effectively suppresses light source fluctuation and environmental noise interference, and long-term monitoring stability is ensured; rapid concentration inversion is realized, reliable data support is provided for fault early warning, and the technical effects of reducing cost and increasing efficiency are achieved on the whole.

Description

Technical Field

[0001] The present invention relates to the technical field of gas detection, and in particular to a multi-cavity gas detection device and method. Background Art

[0002] Among traditional gas detection technologies, photoacoustic spectroscopy (FP) detection devices based on the principle of photoacoustic spectroscopy have been widely used in industrial gas monitoring. These devices typically use lasers to excite the gas molecules being tested, causing them to absorb light energy and undergo thermal relaxation, generating a pressure wave or acoustic signal. This acoustic signal is then converted into an electrical signal by an acoustic sensor, amplified by a lock-in amplifier, and processed by a computer to infer the gas concentration. However, existing technologies have significant limitations, particularly in monitoring insulating gases in power equipment. For example, when SF6 gas is used as an insulating medium in high-voltage electrical equipment, partial discharge or overheating can cause it to decompose into various components, such as CO, SO2, and SO2F2. Traditional FP detection devices are typically only capable of detecting a single gas. Monitoring multiple decomposition products requires deploying multiple detection systems with different laser wavelengths, significantly increasing equipment cost and maintenance complexity while also failing to meet the requirements of real-time on-site monitoring. Furthermore, the optical path design of traditional devices often relies on a single resonant cavity, resulting in limited photoacoustic signal strength, insufficient detection sensitivity, and susceptibility to interference from ambient noise. In complex industrial environments, light source power fluctuations, optical path losses, and cross-interference between multiple gases further reduce detection accuracy and reliability. Therefore, a highly sensitive photoacoustic spectroscopy technology with strong anti-interference capabilities and a compact structure is urgently needed to meet the practical needs of power equipment fault diagnosis and online monitoring of gas insulation status. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is that the traditional FP detection device can only detect a single gas and cannot meet the requirements of multi-component simultaneous monitoring, and has high cost and poor anti-interference.

[0004] The above technical problems are solved by the following technical solutions:

[0005] The present invention provides a multi-cavity gas detection device, which comprises a photoacoustic cell, a multi-band laser output unit, a sensor and a function generator.

[0006] In a preferred embodiment of the multi-cavity gas detection device of the present invention, a photoacoustic cell comprises a plurality of coupled acoustic resonant cavities for carrying a gas to be detected, facilitating a photoacoustic effect between the gas to be detected and a laser beam injected into the photoacoustic cell, thereby generating a photoacoustic signal; a multi-band laser output unit is disposed on one side of the photoacoustic cell and is configured to emit lasers of a plurality of specific wavelengths, generating the laser beams and injecting them into each of the acoustic resonant cavities of the photoacoustic cell;

[0007] The sensors are respectively arranged in each acoustic resonant cavity of the photoacoustic cell and are used to detect the photoacoustic signal in the corresponding acoustic resonant cavity; the function generator is connected to the multi-band laser output unit and is used to control the waveform signal of the laser output by the multi-band laser output unit.

[0008] In a preferred embodiment of the multi-cavity gas detection device of the present invention, it further comprises a lock-in amplifier connected to the sensor for amplifying and extracting the photoacoustic signal;

[0009] A computer is connected to the lock-in amplifier and is used to receive and process the amplified photoacoustic signal and invert it to obtain the concentration of the gas to be measured.

[0010] In a preferred embodiment of the multi-cavity gas detection device of the present invention, the sensor is an FP optical fiber sensor.

[0011] In a preferred embodiment of the multi-cavity gas detection device of the present invention: it also includes a circulator, connected to the phase-locked amplifier, for controlling the optical fiber to unidirectionally output a characteristic frequency photoacoustic signal; a photodiode, connected to the circulator and the sensor, for photoelectric signal conversion.

[0012] In a preferred embodiment of the multi-cavity gas detection device of the present invention, it further comprises a high-speed data acquisition card connected to the lock-in amplifier and the computer, for acquiring the photoacoustic signal and transmitting it to the computer.

[0013] In a preferred embodiment of the multi-cavity gas detection device of the present invention: the function generator controls the multi-band laser output unit to output a sinusoidal wave signal.

[0014] In a preferred embodiment of the multi-cavity gas detection device of the present invention, it further comprises a feedback module connected to the multi-band laser output unit and stabilizing the output wavelength and frequency of the multi-band laser output unit.

[0015] In a preferred embodiment of the multi-cavity gas detection device of the present invention: the feedback module feeds back the status information of the multi-band laser output unit to the function generator, so that the function generator can adjust the output waveform for the multi-band laser output unit.

[0016] The present invention also proposes a multi-cavity gas detection method, which includes introducing the gas to be detected, emitting a multi-band laser beam, detecting photoacoustic signals and inverting gas concentration.

[0017] In a preferred embodiment of the multi-cavity gas detection method of the present invention, the following steps are performed: introducing the gas to be measured into the photoacoustic cell; emitting a multi-band laser beam, controlling the multi-band laser output unit to emit laser beams of several specific wavelengths, respectively incident on each acoustic resonant cavity of the photoacoustic cell, so that the laser and the gas to be measured undergo a photoacoustic effect to generate a photoacoustic signal; detecting the photoacoustic signal, by using a plurality of sensors respectively arranged in each acoustic resonant cavity of the photoacoustic cell, detecting the photoacoustic signal in the corresponding acoustic resonant cavity; inverting the gas concentration, amplifying and extracting the photoacoustic signal by a phase-locked amplifier, and receiving and processing the amplified photoacoustic signal by a computer to invert and obtain the concentration of the gas to be measured.

[0018] In a preferred embodiment of the multi-cavity gas detection method of the present invention: the emission of the multi-band laser beam includes: a feedback module stabilizing the output wavelength and frequency of the multi-band laser output unit, and feeding back status information of the multi-band laser output unit to a function generator; the function generator controls the multi-band laser output unit to output a sinusoidal wave signal.

[0019] The beneficial effects of the present invention are as follows: synchronous high-sensitivity detection of multi-component gases decomposed by SF6 is achieved through a multi-cavity coupling design, which greatly reduces equipment cost and maintenance complexity; the use of sensors combined with photoacoustic effect significantly improves signal strength and detection accuracy; the innovative wavelength feedback control system effectively suppresses light source fluctuations and environmental noise interference, ensuring long-term monitoring stability; and rapid concentration inversion is achieved to provide reliable data support for fault warning, achieving the overall technical effect of reducing costs and increasing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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.

[0021] Figure 1 shows a schematic diagram of a multi-cavity gas detection device;

[0022] Figure 2 A flow chart of a multi-cavity gas detection method is shown. DETAILED DESCRIPTION

[0023] 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.

[0024] 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.

[0025] Reference Figure 1 This embodiment provides a multi-cavity gas detection device, including a photoacoustic cell 3, a multi-band laser output unit 9, a sensor 5 and a function generator 13.

[0026] Specifically, the photoacoustic cell 3 includes several coupled acoustic resonant cavities for carrying the gas to be measured, so that the gas to be measured and the laser beam injected into the photoacoustic cell 3 produce a photoacoustic effect, thereby generating a photoacoustic signal. The photoacoustic cell 3 is the core component of the entire device. It is not a simple cavity, but a plurality of independent acoustic resonant cavities integrated inside. These resonant cavities are coupled to each other to form a whole for accommodating the gas to be measured. When a laser of a specific wavelength is irradiated onto the gas to be measured in the photoacoustic cell, the gas molecules to be measured absorb light energy and release heat, thereby generating sound waves, i.e., the photoacoustic effect. Different gas molecules have different absorption characteristics for light of a specific wavelength. Therefore, by detecting the sound wave signal, the type and concentration of the gas can be analyzed.

[0027] The multi-band laser output unit 9, located on one side of the photoacoustic cell 3, is used to emit lasers of several specific wavelengths. These laser beams are then incident on the various acoustic resonant cavities of the photoacoustic cell 3. The multi-band laser output unit 9 emits a laser light source capable of emitting lasers of multiple specific wavelengths. These laser beams are then directed into the various acoustic resonant cavities within the photoacoustic cell 3, interacting with the gas being measured therein, stimulating the photoacoustic effect. The use of multi-band lasers enables the device to simultaneously detect multiple different gas components, improving detection efficiency.

[0028] Sensors 5 are positioned within each acoustic resonant cavity of the photoacoustic cell 3 to detect the photoacoustic signal within the corresponding cavity. Sensors 5 detect the acoustic wave signals generated by the photoacoustic effect. Because the photoacoustic cell contains multiple independent acoustic resonant cavities, multiple sensors are required, each corresponding to a specific resonant cavity to independently detect the acoustic wave signals within each cavity. This helps distinguish photoacoustic signals generated by different gas components, improving detection accuracy.

[0029] Function generator 13 is connected to multi-band laser output unit 9 and is used to control the waveform signal of the laser light output by multi-band laser output unit 9. Function generator 13 is used to control the waveform of the laser light output, such as a pulse wave or a sine wave. In this embodiment, a sine wave drive is selected. By adjusting the laser light waveform, the generation of the photoacoustic signal can be optimized and the detection sensitivity can be improved.

[0030] When in use, the multi-band laser output unit 9 simultaneously outputs a wave number of 2100cm -1 , 500cm -1 and 1300cm -1 The three wavelengths of laser light correspond to the absorption peaks of CO, SO2 and SO2F2 respectively, and detect the decomposition products of SF6 discharge.

[0031] Reference Figure 1 , this embodiment provides a multi-cavity gas detection device, which is based on the previous embodiment.

[0032] Specifically, the photoacoustic cell 3 includes several coupled acoustic resonant cavities for carrying the gas to be measured, so that the gas to be measured and the laser beam injected into the photoacoustic cell 3 produce a photoacoustic effect, thereby generating a photoacoustic signal. The photoacoustic cell 3 is the core component of the entire device. It is not a simple cavity, but a plurality of independent acoustic resonant cavities integrated inside. These resonant cavities are coupled to each other to form a whole for accommodating the gas to be measured. When a laser of a specific wavelength is irradiated onto the gas to be measured in the photoacoustic cell, the gas molecules to be measured absorb light energy and release heat, thereby generating sound waves, i.e., the photoacoustic effect. Different gas molecules have different absorption characteristics for light of a specific wavelength. Therefore, by detecting the sound wave signal, the type and concentration of the gas can be analyzed.

[0033] The multi-band laser output unit 9, located on one side of the photoacoustic cell 3, is used to emit lasers of several specific wavelengths. These laser beams are then incident on the various acoustic resonant cavities of the photoacoustic cell 3. The multi-band laser output unit 9 emits a laser light source capable of emitting lasers of multiple specific wavelengths. These laser beams are then directed into the various acoustic resonant cavities within the photoacoustic cell 3, interacting with the gas being measured therein, stimulating the photoacoustic effect. The use of multi-band lasers enables the device to simultaneously detect multiple different gas components, improving detection efficiency.

[0034] Sensors 5 are positioned within each acoustic resonant cavity of the photoacoustic cell 3 to detect the photoacoustic signal within the corresponding cavity. Sensors 5 detect the acoustic wave signals generated by the photoacoustic effect. Because the photoacoustic cell contains multiple independent acoustic resonant cavities, multiple sensors are required, each corresponding to a specific resonant cavity to independently detect the acoustic wave signals within each cavity. This helps distinguish photoacoustic signals generated by different gas components, improving detection accuracy.

[0035] Function generator 13 is connected to multi-band laser output unit 9 and is used to control the waveform signal of the laser light output by multi-band laser output unit 9. Function generator 13 is used to control the waveform of the laser light output, such as a pulse wave or a sine wave. In this embodiment, a sine wave drive is selected. By adjusting the laser light waveform, the generation of the photoacoustic signal can be optimized and the detection sensitivity can be improved.

[0036] Specifically, it also includes a lock-in amplifier 8 connected to the acoustic sensor 5 for amplifying and extracting the photoacoustic signal.

[0037] The phase-locked amplifier 8 is used to isolate non-correlated noise signals, amplify and extract the photoacoustic signal of the gas being measured, wherein the noise signal is the noise of other people talking or other machine noise in the actual laboratory. The filtering function of the phase-locked amplifier 8 can be used to isolate or remove waveforms that are not characteristic frequencies.

[0038] The computer 14 is connected to the lock-in amplifier 8 and is used to receive and process the amplified photoacoustic signal and invert it to obtain the concentration of the gas to be measured.

[0039] The computer 14 receives the photoacoustic signal processed by the lock-in amplifier 8 and then performs concentration inversion on the photoacoustic signal through fast Fourier transform.

[0040] Specifically, the acoustic sensor 5 is an FP optical fiber sensor.

[0041] The acoustic sensor 5 is used to detect the photoacoustic signal generated when the laser emitted by the multi-band laser output unit 9 acts on the gas to be measured, and then transmit it to the lock-in amplifier 8.

[0042] Specifically, it also includes a circulator 6 connected to a phase-locked amplifier 8 for controlling the optical fiber to unidirectionally output a characteristic frequency photoacoustic signal.

[0043] The photodiode 7 is connected to the circulator 6 and the acoustic sensor 5 and is used for photoelectric signal conversion.

[0044] The circulator 6 is used to guide the optical signal of a specific frequency obtained from the acoustic sensor 5 to the phase-locked amplifier 8 to improve the signal purity and detection efficiency. In order to ensure the reliability and repeatability of the experiment, an acoustic signal of 10 to 100 Hz is generally input with a step size of 10 Hz.

[0045] Specifically, it also includes a high-speed data acquisition card 10, which is connected to the phase-locked amplifier 8 and the computer 14, and is used to collect the photoacoustic signal and transmit it to the computer 14, so that the computer 14 can further process and analyze the photoacoustic signal.

[0046] Specifically, it also includes a feedback module 12, which is connected to the multi-band laser output unit 9 and stabilizes the output wavelength and frequency of the multi-band laser output unit 9; the feedback module 12 also feeds back the status information of the multi-band laser output unit 9 to the function generator 13, so that the function generator 13 can adjust the output waveform for the multi-band laser output unit 9.

[0047] The function generator 13 adjusts the laser driver 11 according to the data fed back by the feedback module 12 , thereby stabilizing the output wavelength and frequency of the multi-band laser output unit 9 .

[0048] During use, the gas to be measured is introduced into a photoacoustic cell 3 containing several coupled acoustic resonant cavities. Then, under the control of a function generator 13, the multi-band laser output unit 9 emits laser beams of several specific wavelengths, which are incident on each resonant cavity of the photoacoustic cell 3, interacting with the gas to be measured to generate photoacoustic signals. Sensors within each resonant cavity detect these photoacoustic signals, which are converted into electrical signals by a circulator 6 and a photodiode 7, and then amplified and extracted by a lock-in amplifier 8. A high-speed data acquisition card 10 transmits the processed photoacoustic signals to a computer 14, which analyzes these signals and ultimately infers the concentration of the gas to be measured. Simultaneously, a feedback module 12 monitors and stabilizes the output characteristics of the laser and feeds back status information to the function generator 13. The function generator 13 adjusts the laser driver 11 based on the data fed back by the feedback module 12, thereby stabilizing the output wavelength and frequency of the multi-band laser output unit 9, optimizing the laser output waveform, and ensuring detection accuracy.

[0049] Reference Figure 2 This embodiment provides a multi-cavity gas detection method, including introducing the gas to be tested, emitting a multi-band laser beam, detecting photoacoustic signals and inverting gas concentration.

[0050] Specifically, the gas to be tested is introduced into the photoacoustic cell 3, and the gas to be tested is introduced from the air inlet 2 of the photoacoustic cell 3 through an air pump connected to the solenoid valve 1, and then the gas is discharged from the air outlet 3 after passing through the acoustic resonance cavity in the photoacoustic cell 3 and also passing through another solenoid valve 1, and the exhaust gas after detection is recovered.

[0051] Emitting multi-band laser beams, controlling the multi-band laser output unit 9 to emit several laser beams of specific wavelengths, respectively incident on each acoustic resonant cavity of the photoacoustic pool 3, so that the laser and the gas to be detected produce a photoacoustic effect. The laser beam has multiple bands, and each band of the laser beam corresponds to a gas to be detected. The output wave number is 2100cm -1 , 500cm -1 and 1300cm -1 The three wavelengths of laser light correspond to the absorption peaks of CO, SO2 and SO2F2 respectively, and detect the decomposition products of SF6 discharge.

[0052] Generate a photoacoustic signal; detect the photoacoustic signal, and detect the photoacoustic signal in the corresponding acoustic resonant cavity through multiple sensors 5 respectively arranged in each acoustic resonant cavity of the photoacoustic pool 3; the sensor 5 can monitor the photoacoustic signal generated by the gas absorbing the laser in the corresponding resonant cavity in real time.

[0053] To invert gas concentration, the lock-in amplifier 8 amplifies and extracts the photoacoustic signal, which is then received and processed by the computer 14 to invert the concentration of the gas being measured. The amplified and extracted photoacoustic signal from the lock-in amplifier 8 is transmitted to the computer 14 via the high-speed data acquisition card 10. The computer 14 analyzes the photoacoustic signals of varying intensities generated by laser excitation at different wavelengths and, combined with the spectral characteristics of the gas, ultimately calculates and displays the concentration information for each component in the gas being measured.

[0054] Emitting a multi-band laser beam includes: the feedback module 12 stabilizes the output wavelength and frequency of the multi-band laser output unit 9, and feeds back the status information of the multi-band laser output unit 9 to the function generator 13; the function generator 13 controls the multi-band laser output unit 9 to output a sine wave signal.

[0055] During the laser beam emission process, to ensure the accuracy and reliability of the experiment, the laser output by the multi-band laser output unit 9 must have a stable wavelength and frequency. The feedback module 12 continuously detects the wavelength and frequency of the laser beam actually emitted by the multi-band laser output unit 9 and feeds this information back to the function generator 13. Once drift or fluctuation in the output wavelength or frequency of the multi-band laser output unit 9 is detected, the function generator 13 issues an adjustment command to adjust the output of the multi-band laser output unit 9 to stabilize the wavelength and frequency of the laser beam.

[0056] 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 multi-cavity gas detection device, characterized in that: include, The photoacoustic cell (3) comprises a plurality of coupled acoustic resonant cavities for carrying a gas to be measured, so as to facilitate the photoacoustic effect produced by the gas to be measured and the laser beam injected into the photoacoustic cell (3), thereby generating a photoacoustic signal; A multi-band laser output unit (9) is arranged on one side of the photoacoustic cell (3) and is used to emit lasers of several specific wavelengths, generate the laser beams and respectively inject them into the acoustic resonant cavities of the photoacoustic cell (3); Sensors (5) are respectively arranged in each acoustic resonance cavity of the photoacoustic cell (3) and are used to detect the photoacoustic signal in the corresponding acoustic resonance cavity; The function generator (13) is connected to the multi-band laser output unit (9) and is used to control the waveform signal of the laser output by the multi-band laser output unit (9).

2. The multi-cavity gas detection device according to claim 1, characterized in that: It also includes a lock-in amplifier (8), connected to the sensor (5), for amplifying and extracting the photoacoustic signal; A computer (14) is connected to the lock-in amplifier (8) and is used to receive and process the amplified photoacoustic signal and invert the signal to obtain the concentration of the gas to be measured.

3. The multi-cavity gas detection device according to claim 2, characterized in that: The sensor (5) is an FP optical fiber type sensor.

4. The multi-cavity gas detection device according to claim 3, characterized in that: It also includes a circulator (6) connected to the phase-locked amplifier (8) and used to control the optical fiber to unidirectionally output a characteristic frequency photoacoustic signal; A photodiode (7) is connected to the circulator (6) and the sensor (5) and is used for photoelectric signal conversion.

5. The multi-cavity gas detection device according to claim 4, characterized in that: It also includes a high-speed data acquisition card (10) connected to the phase-locked amplifier (8) and the computer (14) for acquiring the photoacoustic signal and transmitting it to the computer (14).

6. The multi-cavity gas detection device according to claim 5, characterized in that: The function generator (13) controls the multi-band laser output unit (9) to output a sine wave signal.

7. The multi-cavity gas detection device according to claim 6, characterized in that: It also includes a feedback module (12) connected to the multi-band laser output unit (9) and stabilizing the output wavelength and frequency of the multi-band laser output unit (9).

8. The multi-cavity gas detection device according to claim 7, characterized in that: The feedback module (12) feeds back the state information of the multi-band laser output unit (9) to the function generator (13), so that the function generator (13) can adjust the output waveform for the multi-band laser output unit (9).

9. A multi-cavity gas detection method, characterized by: The multi-cavity gas detection device applicable to any of claims 1 to 8 comprises: Introducing a gas to be measured into the photoacoustic cell (3); Emitting a multi-band laser beam, controlling the multi-band laser output unit (9) to emit a plurality of laser beams of specific wavelengths, respectively incident on each acoustic resonant cavity of the photoacoustic cell (3), causing the laser to generate a photoacoustic effect with the gas to be measured, and generating a photoacoustic signal; Detecting the photoacoustic signal by using a plurality of sensors (5) respectively arranged in each acoustic resonance cavity of the photoacoustic cell (3) to detect the photoacoustic signal in the corresponding acoustic resonance cavity; The gas concentration is inverted, the photoacoustic signal is amplified and extracted by a phase-locked amplifier (8), and the amplified photoacoustic signal is received and processed by a computer (14), and the concentration of the gas to be measured is inverted.

10. The multi-cavity gas detection method according to claim 9, characterized in that: The emitting multi-band laser beam includes a feedback module (12) stabilizing the output wavelength and frequency of the multi-band laser output unit (9), and feeding back state information of the multi-band laser output unit (9) to a function generator (13); The function generator (13) controls the multi-band laser output unit (9) to output a sine wave signal.

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