A portable hydrogen gas sensing device based on quartz-enhanced technology

Abstract

The application discloses a portable hydrogen sensing device based on quartz enhanced photoacoustic spectroscopy (QEPAS) technology, which comprises a box body, a control module, a light source excitation module, an acoustic detection module, a QEPAS gas chamber and a lock-in amplification module. The light source excitation module emits modulated infrared light into the QEPAS gas chamber. In the QEPAS gas chamber, the modulated infrared light generates a photoacoustic effect by taking water vapor as a pump gas. Under the action of the photoacoustic effect, the acoustic detection module detects the to-be-detected gas in real time to obtain a detection signal. The control module and the lock-in amplification module process the detection signal to calculate the hydrogen concentration of the to-be-detected gas. The box body is used as a carrier, so that the portable hydrogen sensing device is convenient to carry and install. Under the action of the photoacoustic effect, the QEPAS gas chamber and the acoustic detection module detect the to-be-detected gas, can accurately and quickly respond to the change of the hydrogen concentration in the external environment, improve the response speed of detecting the hydrogen concentration, and better guarantee the safety of personnel.

Description

Technical Field

[0001] This invention relates to the field of gas sensor technology, and in particular to a portable hydrogen sensing device based on quartz enhancement technology. Background Technology

[0002] Nowadays, the use of hydrogen is becoming more and more common, but deflagration and explosion are very likely to occur during the production, use and storage of hydrogen.

[0003] In existing technologies, portable hydrogen detectors are basically based on electrochemical methods to measure hydrogen, but the detection range is greatly limited, the linearity is not very good, and the lifespan is short. Surface acoustic wave technology has low qualitative and selective properties. Fiber optic hydrogen sensors all have certain drawbacks to varying degrees, such as the inability to produce a linear hydrogen concentration response due to the structure of the sensitive membrane, insufficient sensitivity, and high cost, which prevent them from being put into practical use.

[0004] Therefore, the aforementioned hydrogen detection devices all struggle to achieve sensitive and accurate real-time hydrogen detection while meeting users' safety performance requirements, all while saving costs. Summary of the Invention

[0005] The purpose of this invention is to provide a portable hydrogen sensing device based on quartz enhancement technology to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.

[0006] The solution to the technical problem of this invention is to provide a portable hydrogen sensing device based on quartz enhancement technology, comprising: a housing, a control module, a light source excitation module, an acoustic detection module, a QEPAS gas chamber, and a lock-in amplification module;

[0007] The control module, light source excitation module, QEPAS chamber, and lock-in amplification module are all located inside the enclosure. The acoustic detection module is located in the QEPAS chamber. The control module is connected to the light source excitation module and the lock-in amplification module respectively. The acoustic detection module is connected to the lock-in amplification module. Ventilation openings are provided at the bottom of both sides of the enclosure. The gas to be tested enters the interior of the enclosure through the ventilation openings to enter the QEPAS chamber.

[0008] The control module outputs a modulation signal to the light source excitation module, which emits modulated infrared light according to the modulation signal and horizontally directs the modulated infrared light into the QEPAS gas chamber.

[0009] In the QEPAS gas chamber, the modulated infrared light is used to pump water vapor in the gas to be tested as a pump gas to generate a photoacoustic effect. The acoustic detection module is used to detect the gas to be tested based on the photoacoustic effect and output a detection signal.

[0010] The lock-in amplifier module is used to amplify the detection signal and transmit it to the control module. The control module calculates the hydrogen concentration in the gas to be tested based on the amplified detection signal.

[0011] Furthermore, the QEPAS air chamber includes: a shell, a first transparent mirror, a second transparent mirror, and an H-shaped resonant cavity;

[0012] The housing has an internal air chamber and a ventilation pipe on one side of the housing. The ventilation pipe is connected to the air chamber, and the gas to be tested enters the air chamber through the ventilation pipe.

[0013] The light source excitation module is located at one end of the gas chamber, a fixing component is provided in the middle of the gas chamber, the H-shaped resonant cavity is mounted on the fixing component, the first light-transmitting mirror is located on both sides of the H-shaped resonant cavity, and the second light-transmitting mirror is located at the other end of the gas chamber.

[0014] Furthermore, the H-type resonant cavity includes: a first buffer cavity, a second buffer cavity, and a slit tube;

[0015] The slit tube has a detection port in the center of both sides. One side of the first buffer chamber is connected to the first light-transmitting mirror, and the other side of the first buffer chamber is connected to one end of the slit tube. One side of the second buffer chamber is connected to the other end of the slit tube, and the other side of the second buffer chamber is connected to the first light-transmitting mirror.

[0016] The modulated infrared light passes through the first light-transmitting mirror and horizontally enters the first buffer cavity, passes through the slit tube, and exits horizontally from the second buffer cavity through the first light-transmitting mirror to the second light-transmitting mirror.

[0017] Furthermore, the acoustic detection module includes: a quartz tuning fork and a transimpedance amplifier;

[0018] The quartz tuning fork is connected to a transimpedance amplifier. The quartz tuning fork is equipped with a piezoelectric crystal. The transimpedance amplifier is located at the top of the housing. The top of the housing is equipped with a detection channel. The fork arm of the quartz tuning fork passes through the detection channel and is inserted into the air chamber.

[0019] The slit tube passes through the gap between the forks of the quartz tuning fork, and the forks of the quartz tuning fork are perpendicular to the slit tube, so that the tips of the forks of the quartz tuning fork face the detection port.

[0020] The modulated infrared light passes through the slit tube, and according to the photoacoustic effect, the quartz tuning fork generates an oscillation decay signal. The piezoelectric crystal converts the oscillation decay signal into a current signal, and the transimpedance amplifier outputs the detection signal based on the current signal.

[0021] Furthermore, a portable hydrogen sensing device based on quartz enhancement technology also includes: a temperature and humidity compensator;

[0022] The temperature and humidity compensator is connected to the light source excitation module. The temperature and humidity compensator is used to acquire the current temperature and humidity information, process the temperature and humidity information, and output a compensation signal to the light source excitation module.

[0023] Furthermore, the light source excitation module includes: a DFB laser and a laser driving unit;

[0024] The input terminal of the laser driving unit is connected to the control module, and the DFB laser is connected to the output terminal of the laser driving unit. The laser driving unit outputs a driving signal to the DFB laser according to the modulation signal and the compensation signal, and the DFB laser emits modulated infrared light according to the driving signal.

[0025] Furthermore, a portable hydrogen sensing device based on quartz enhancement technology also includes: a warning light and a buzzer;

[0026] Both the warning light and the buzzer are connected to the control module. The warning light is located on the top of the enclosure. When the hydrogen concentration is higher than the set concentration threshold, the control module controls both the warning light and the buzzer to respond and issue a warning signal.

[0027] Furthermore, a portable hydrogen sensing device based on quartz enhancement technology also includes: a grip and a fixing component;

[0028] The handle is located on the top of the box, and the fixing component is located on one side of the box. The fixing component is used to fix the installation position of the box.

[0029] Furthermore, a portable hydrogen sensing device based on quartz enhancement technology also includes: a human-computer interaction module;

[0030] The human-machine interaction module is connected to the control module. The human-machine interaction module is used to acquire user commands and display hydrogen concentration. According to the user commands, the control module controls the warning light and buzzer to stop responding.

[0031] Furthermore, a portable hydrogen sensing device based on quartz enhancement technology also includes: an exhaust fan;

[0032] The exhaust fans are located on the top of both sides of the housing and are connected to the control module.

[0033] The beneficial effects of this invention are as follows: Modulated infrared light is emitted into the QEPAS gas chamber via a light source excitation module. Within the QEPAS gas chamber, the modulated infrared light, using water vapor as a pump gas, generates a photoacoustic effect. Under the influence of this effect, the acoustic detection module detects the gas to be measured in real time, obtaining a detection signal. This signal is then processed by a lock-in amplification module and a control module to calculate the current hydrogen concentration of the gas to be measured. This invention, by using a housing as a carrier, reduces complex mechanical structures, making it easier for users to carry and install. The modulated infrared light photoacoustic effect technology has low energy consumption, a large measurement range, and strong stability, reducing maintenance costs. Under the influence of the photoacoustic effect, the QEPAS gas chamber and acoustic detection module detect the gas to be measured, enabling accurate and rapid responses to changes in external hydrogen concentration, improving the response speed for hydrogen concentration detection and better ensuring personnel safety. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of a portable hydrogen sensing device based on quartz enhancement technology according to an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the QEPAS air chamber structure provided in one embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of an acoustic detection module and an H-type resonant cavity structure provided in one embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of the cross-sectional structure of an H-type resonant cavity provided in one embodiment of the present invention.

[0038] Reference numerals: Box 100, Ventilation vent 110, Warning light 120, Handle 130, Fixing component 140, Partition 160, Battery 170;

[0039] QEPAS air chamber 200, housing 210, ventilation pipe 211, air chamber 212, fixing hole 213, fixing piece 214, detection pipe 215, first light transmission lens 220, H-type resonant cavity 230, first buffer cavity 231, second buffer cavity 232, slit tube 233, detection port 234, second light transmission lens 240;

[0040] Light source excitation module 300, control module 400, lock-in amplifier module 500, quartz tuning fork 600, transimpedance amplifier 610. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and should not be construed as limiting the scope of the invention.

[0042] It should be noted that although functional modules are divided in the system diagram, in some cases, the steps shown or described may be executed in a different order than the module division or flowchart shown in the system. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0043] In the description of this invention, it should be noted that, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0044] QEPAS technology, also known as quartz-enhanced photoacoustic spectroscopy, utilizes the high Q value of quartz tuning forks to enhance the signal-to-noise ratio of photoacoustic spectroscopy, effectively improving the anti-interference capability of photoacoustic spectroscopy, but reducing the intensity of the sound signal.

[0045] The photoacoustic effect refers to the phenomenon that a material generates mechanical waves when it is irradiated with light of periodically modulated intensity. When a medium is irradiated with light, the absorption of light by the medium causes changes in its internal temperature and humidity, resulting in structural and volume changes in certain regions of the medium. When a pulsed or modulated light source is used, the rise and fall of the medium's temperature and humidity will cause the medium's volume to expand and contract, thus radiating mechanical waves outward.

[0046] Reference Figure 1 In some embodiments of the present invention, a portable hydrogen sensing device based on quartz enhancement technology includes: a housing 100, a QEPAS gas chamber 200, a control module 400, a light source excitation module 300, an acoustic detection module, and a lock-in amplification module 500.

[0047] The QEPAS chamber 200 is located inside the enclosure 100. The acoustic detection module is located inside the QEPAS chamber 200. The control module 400, the light source excitation module 300, and the lock-in amplifier module 500 are all located inside the enclosure 100.

[0048] The input terminal of the light source excitation module 300 is connected to the control module 400, and the output terminal of the light source excitation module 300 is located in the QEPAS gas chamber 200. The output terminal of the acoustic detection module is connected to the input terminal of the lock-in amplifier module 500, and the output terminal of the lock-in amplifier module 500 is connected to the control module 400.

[0049] The chamber 100 has ventilation openings 110 on both sides. The gas to be tested can flow into the interior of the chamber 100 through the ventilation openings 110, and then into the interior of the QEPAS gas chamber 200.

[0050] The control module 400 provides a modulation signal to the light source excitation module 300. According to the modulation signal, the light source excitation module 300 emits modulated infrared light and horizontally directs the modulated infrared light into the interior of the QEPAS gas chamber 200.

[0051] Inside the QEPAS gas chamber 200, the emitted modulated infrared light passes through the acoustic detection module, using water vapor in the gas under test as the pump gas to generate a photoacoustic effect. Under the action of the photoacoustic effect, the acoustic detection module detects the gas under test and outputs a detection signal to the lock-in amplifier module 500. The pump gas refers to the gas that absorbs laser energy to generate sound waves or sound pressure.

[0052] The lock-in amplifier module 500 extracts the weak detection signal emitted by the acoustic detection module in the QEPAS gas chamber 200, amplifies and converts it, and outputs it to the control module 400 to improve the signal-to-noise ratio of the detection signal. Based on the detection signal after amplification and conversion, the control module 400 calculates the hydrogen concentration in the gas to be tested, thus completing the real-time detection of the gas to be tested.

[0053] The light source excitation module 300 emits modulated infrared light into the QEPAS gas chamber 200. In the QEPAS gas chamber 200, the modulated infrared light, using water vapor as pump gas, generates a photoacoustic effect. Under the action of the photoacoustic effect, the acoustic detection module detects the gas to be measured in real time and obtains the detection signal. The detection signal is processed by the lock-in amplifier module 500 and the control module 400 to calculate the current hydrogen concentration of the gas to be measured.

[0054] This invention reduces complex mechanical structures and product size by using the housing 100 as a carrier, making it easier for users to carry and install. The technology for generating photoacoustic effects by modulating infrared light has low energy consumption, is non-toxic, highly accurate, has a large measuring range, and strong stability. It can reduce maintenance costs, has high safety performance, and does not produce any open flames or high temperatures.

[0055] Under the effect of photoacoustic, the QEPAS gas chamber 200 and acoustic detection module can detect the gas to be tested, and can make an accurate and rapid response to changes in the external hydrogen concentration, thereby improving the response speed of hydrogen concentration detection and better ensuring the safety of personnel.

[0056] Compared to existing electrochemical methods for hydrogen measurement, this invention utilizes the photoacoustic effect, resulting in superior performance in terms of measurement range, linearity, and lifespan. Furthermore, compared to fiber optic sensors, this portable hydrogen sensing device is more cost-effective and practical.

[0057] Reference Figures 1 to 3 In some embodiments of the present invention, the QEPAS air chamber 200 includes: a housing 210, a first light-transmitting mirror 220, an H-shaped resonant cavity 230, and a second light-transmitting mirror 240.

[0058] The housing 210 has an internal air chamber 212, and a ventilation pipe 211 is provided on one side of the housing 210. There are two ventilation pipes 211. The ventilation pipes 211 are connected to the air chamber 212, allowing the gas to be tested flowing into the housing 100 from the vent 110 to flow into the air chamber 212 through the ventilation pipes 211. The housing 210 consists of a ventilation housing and a mounting housing. Both the ventilation housing and the mounting housing have fixing holes 213 and corresponding grooves inside. The ventilation housing and the mounting housing are connected through the fixing holes 213 to form the housing, thereby creating the air chamber 212 through the corresponding grooves inside, for photoacoustic effect response.

[0059] The laser emitting end of the light source excitation module 300 is located at one end of the gas chamber 212. Inside the gas chamber 212, the light source excitation module 300 horizontally emits modulated infrared light, which passes through the acoustic detection module and runs through the entire gas chamber 212. A fixing member 214 is provided in the middle of the gas chamber 212. The fixing member 214 is used to fix the H-type resonant cavity 230 so that the modulated infrared light can pass through the H-type resonant cavity 230 and generate a photoacoustic effect in the H-type resonant cavity 230.

[0060] The first transparent mirror 220 is disposed on both sides of the H-shaped resonant cavity 230. That is, the first transparent mirror 220 is provided on one side of the H-shaped resonant cavity 230, and the first transparent mirror 220 is also provided on the other side of the H-shaped resonant cavity 230. The first transparent mirror 220 ensures high transmittance of modulated infrared light, allowing the modulated infrared light to converge into the H-shaped resonant cavity 230, and making the H-shaped resonant cavity 230 semi-sealed. The first transparent mirror 220 and the H-shaped resonant cavity 230 form a semi-sealed sound-enhancing gas cavity, which can effectively enhance the sound pressure generated when the modulated infrared light passes through the gas to be measured and absorbs the gas.

[0061] The second light-transmitting mirror 240 is disposed at the other end of the gas chamber 212, which can converge the modulated infrared light that passes through the entire gas chamber 212, so that the modulated infrared light exits the gas chamber 212, thereby preventing the scattered modulated infrared light from affecting the photoacoustic effect generated by the H-type resonant cavity 230. The mirror surfaces of the first light-transmitting mirror 220 and the second light-transmitting mirror 240 are both perpendicular to the horizontally incident modulated infrared light.

[0062] This can be understood as follows: for the internal structure of the QEPAS air chamber 200, the modulated infrared light passes sequentially through the first transparent mirror 220, the H-type resonant cavity 230, the first transparent mirror 220, and the second transparent mirror 240.

[0063] By configuring the air chamber 212, ventilation pipe 211, first transparent mirror 220, second transparent mirror 240, and H-shaped resonant cavity 230 within the housing 210, a resonant air chamber with high sealing performance and low susceptibility to environmental influences is constructed. Compared to existing technologies that use non-resonant air chambers as the site for photoacoustic effects, non-resonant air chambers may result in poor signal stability due to issues such as poor airtightness and inappropriate modulation parameter selection.

[0064] Reference Figures 1 to 4 In some embodiments of the present invention, the H-type resonant cavity 230 includes: a first buffer cavity 231, a second buffer cavity 232, and a slit tube 233.

[0065] The first buffer cavity 231 is connected to one end of the slit tube 233, and the other end of the slit tube 233 is connected to the second buffer cavity 232 to form an H-type resonant cavity 230. The slit tube 233 is a capillary tube.

[0066] The slit tube 233 has detection ports 234 located at the center of both sides. A first transparent lens 220 is connected to one side of the first buffer cavity 231, the other side of the first buffer cavity 231 is connected to one end of the slit tube 233, the other end of the slit tube 233 is connected to one side of the second buffer cavity 232, and the other side of the second buffer cavity 232 is connected to another first transparent lens 220. This forms a semi-closed sound-enhancing gas cavity, which can effectively enhance the sound pressure generated when modulated infrared light passes through the gas to be measured and absorbs the gas.

[0067] This can be understood as follows: In the air chamber 212, modulated infrared light is horizontally incident into the first buffer chamber 231 through a first light-transmitting mirror 220, enters the slit tube 233 from the first buffer chamber 231, passes out from the slit tube 233, enters the second buffer chamber 232, exits from the second buffer chamber 232, passes through another first light-transmitting mirror 220 and horizontally exits to the second light-transmitting mirror 240, and finally exits the air chamber 212.

[0068] In this embodiment, a first light-transmitting mirror 220 is provided on one side of the first buffer cavity 231 and the other side of the second buffer cavity 232 to enhance the modulation of infrared light. This allows the sound pressure generated when the modulation of infrared light passes through the gas to be tested and absorbs the gas to be focused into the slit tube 233. In other words, by sequentially and horizontally arranging the first light-transmitting mirror 220, the first buffer cavity 231, the slit tube 233, the second buffer cavity 232, and the first light-transmitting mirror 220, a semi-closed sound-enhancing resonant gas cavity is formed, which can effectively enhance the sound pressure generated when the modulation of infrared light passes through the gas to be tested and absorbs the gas, and focus it into the slit tube 233.

[0069] In this embodiment, a first buffer cavity 231 and a second buffer cavity 232 are respectively provided on both sides of the slit tube 233 to improve the signal-to-noise ratio of the acoustic signal and further improve the detection accuracy of QEPAS technology. The first buffer cavity 231 and the second buffer cavity 232 can be constructed using 3D printing technology. Because the inner diameter of the resonant tube in the prior art is extremely small, there are extremely high requirements for processing precision. Therefore, it was difficult to apply this method to QEPAS technology in the past. However, now the first buffer cavity 231 and the second buffer cavity 232 can be constructed using 3D printing technology.

[0070] Reference Figures 1 to 4 In some embodiments of the present invention, the acoustic detection module includes a quartz tuning fork 600 and a transimpedance amplifier 610.

[0071] The surface of the quartz tuning fork 600 is provided with a piezoelectric crystal. The tail end of the quartz tuning fork 600 is connected to and fixed on the transimpedance amplifier 610. The transimpedance amplifier 610 is installed on the top of the housing 210. A detection channel 215 is provided on the top of the housing 210. Through the detection channel 215, the fork arm of the quartz tuning fork 600 is inserted into the air chamber 212 inside the housing 210 to detect the sound pressure generated by the photoacoustic effect in the semi-sealed QEPAS air chamber 200.

[0072] The slit tube 233 passes through the gap between the fork arms of the quartz tuning fork 600 and is perpendicular to the fork arms of the quartz tuning fork 600, so that the tip of the fork arm of the quartz tuning fork 600 can be at the same horizontal position as the detection port 234 of the slit tube 233, and the arm surface of the tip of the fork arm can face the detection port 234; that is, the modulated infrared light in the slit tube 233 generates a photoacoustic effect through water vapor as pump gas, and the sound pressure generated by the photoacoustic effect can be sensed by the fork arm of the quartz tuning fork 600 through the detection port 234, and a frequency shift phenomenon is generated.

[0073] In this embodiment, the method for detecting the gas to be tested is as follows: BF-QEPAS (beat frequency-quartz enhanced photoacoustic spectroscopy) is combined with the sound velocity method to detect the gas to be tested and output a detection signal, thereby indirectly obtaining the hydrogen concentration; the sound velocity method for hydrogen detection is based on the four-fold difference in sound velocity between hydrogen and air.

[0074] The specific implementation method of determining hydrogen concentration by combining BF-QEPAS (beat frequency-quartz enhanced photoacoustic spectroscopy) with the sound velocity method is as follows: Modulated infrared light is used, and water vapor is used as the pump gas to generate a photoacoustic effect, exciting a quartz tuning fork 600 to vibrate. Due to the frequency shift caused by hydrogen, the quartz tuning fork 600 generates an oscillation decay signal in a very short time. This oscillation decay signal is converted into a weak current signal by a piezoelectric crystal and output to a transimpedance amplifier 610. The transimpedance amplifier 610 amplifies and converts the current signal into a detection signal, which is then output to a lock-in amplifier module 500 for a second amplification. Based on the detection signal after the second amplification, the control module 400 calculates the hydrogen concentration.

[0075] The detection signal is a voltage signal, which includes the amplitude of the oscillation decay signal and the time interval between adjacent peaks and troughs in the oscillation decay signal. In other words, the control module 400 can calculate the resonant frequency of the quartz tuning fork 600 and the pump gas concentration at this time based on the amplitude of the oscillation decay signal and the time interval between adjacent peaks and troughs in the oscillation decay signal, thereby quickly detecting the hydrogen concentration.

[0076] In this embodiment, the beat frequency quartz tuning fork 600 enhancement technology is used for hydrogen detection, which can achieve a response speed of 10ms. This response speed is relatively rare among existing hydrogen detection sensors, indicating that it can accurately and quickly respond to changes in the external hydrogen concentration, thereby improving the response speed of hydrogen concentration detection and better ensuring personnel safety.

[0077] Reference Figures 1 to 3 In some embodiments of the present invention, a portable hydrogen sensing device based on quartz enhancement technology further includes a temperature and humidity compensator.

[0078] The output of the temperature and humidity compensator is connected to the input of the light source excitation module 300. The temperature and humidity compensator is used to acquire the current temperature and humidity information in the environment of the gas to be measured. Based on the current temperature and humidity information, it outputs a compensation signal to the light source excitation module 300. The compensation signal includes a temperature compensation signal and a humidity compensation signal.

[0079] Due to the rapid detection of the resonant frequency (10ms) by the BF-QEPAS, its combination with the sound velocity method for measuring hydrogen concentration can be applied in practical work. However, ambient temperature and humidity will affect the frequency shift of the quartz tuning fork 600, so temperature compensation signals and humidity compensation signals are also required for practical applications.

[0080] Reference Figures 1 to 3 In some embodiments of the present invention, the light source excitation module 300 includes a DFB laser and a laser driving unit.

[0081] The input end of the laser drive unit is electrically connected to the control module 400, and the output end of the laser drive unit is electrically connected to the input end of the DFB laser. The laser emitting end of the DFB laser is fixedly installed at one end of the gas chamber 212.

[0082] The control module 400 sends a modulation signal to the laser drive unit, and the temperature and humidity compensator sends a compensation signal to the laser drive unit. Based on the modulation and compensation signals, the laser drive unit sends a drive signal to the DFB laser. According to the drive signal, the laser emitting end of the DFB laser horizontally emits corresponding modulated infrared light into the gas chamber 212. This allows for targeted modulation of the emitted infrared light based on the changing trend of the gas to be measured, improving the accuracy of hydrogen concentration detection.

[0083] In this embodiment, the light source excitation module 300 also includes a laser protection unit, which can protect the back-end circuit unit when the DFB laser is short-circuited.

[0084] A DFB (Distributed Feedback Laser) is a side-emitting semiconductor laser. The most significant characteristics of a DFB laser are its excellent monochromaticity (i.e., spectral purity), with linewidths typically below 1 MHz, and a very high side-mode suppression ratio (SMSR). In this embodiment, the DFB laser is capable of emitting modulated infrared laser light. For hydrogen detection devices requiring high precision, the spectral purity of the DFB laser is more suitable for this invention compared to other lasers. Utilizing this linewidth and SMSR improves the range and linearity of hydrogen concentration measurement in this invention. Furthermore, infrared photoacoustic spectroscopy technology is energy-efficient, non-toxic, highly accurate, has a large range, superior long-term stability, a long lifespan, and requires minimal maintenance, reducing subsequent maintenance costs. Moreover, infrared photoacoustic spectroscopy is very safe, producing no open flames or high temperatures.

[0085] Reference Figures 1 to 3 In some embodiments of the present invention, a portable hydrogen sensing device based on quartz enhancement technology further includes: a warning light 120 and a buzzer.

[0086] The output of the control module 400 is electrically connected to the warning light 120, and the output of the control module 400 is electrically connected to the buzzer. The warning light 120 is installed on the top of the enclosure 100. There are no restrictions on the installation position of the buzzer within the enclosure 100.

[0087] When the set concentration threshold is lower than the hydrogen concentration calculated by the control module 400, the control module 400 sends a first control signal to the warning light 120, controlling the warning light 120 to respond and emit a flashing light warning; the control module 400 sends a second control signal to the buzzer, controlling the buzzer to respond and emit an audible warning, so that when the hydrogen concentration is too high and causes danger, the warning light flashes and the buzzer sounds to issue a warning signal in a timely manner.

[0088] Reference Figures 1 to 3 In some embodiments of the present invention, a portable hydrogen sensing device based on quartz enhancement technology further includes a human-computer interaction module.

[0089] The human-machine interface module is electrically connected to the control module 400, and the human-machine interface module is mounted on the enclosure 100. The control module 400 sends the obtained hydrogen concentration to the human-machine interface module, which then displays the hydrogen concentration.

[0090] The human-computer interaction module receives and responds to user commands, sending a stop signal to the control module 400. Based on the stop signal, the control module 400 controls the warning light 120 to stop responding and the buzzer to stop responding, thereby canceling the warning signal.

[0091] In this embodiment, the human-machine interface module can be an LCD screen. The control module 400 is also equipped with a high-speed DA / AD unit and a wireless communication unit. The high-speed DA / AD unit enables high-speed data acquisition and conversion; the wireless communication unit and the human-machine interface module can be networked, allowing users to remotely monitor hydrogen concentration trends and receive early warnings of abnormal situations, helping them eliminate safety hazards before accidents occur.

[0092] Reference Figures 1 to 3 In some embodiments of the present invention, a portable hydrogen sensing device based on quartz enhancement technology further includes a grip 130 and a fixing member 140.

[0093] A handle 130 is provided on the top of the housing 100, which allows the user to lift the housing 100 to carry the hydrogen sensor with them, thus improving convenience.

[0094] A fixing member 140 is provided on one side of the enclosure 100. The fixing member 140 is used to fix the installation position of the enclosure 100. In other words, the user can fix the enclosure 100 to the wall or shelf through the fixing member 140.

[0095] Reference Figures 1 to 3 In some embodiments of the present invention, a portable hydrogen sensing device based on quartz enhancement technology further includes an exhaust fan 150.

[0096] Exhaust fans 150 are located on both sides of the enclosure 100, above the vents 110, and connected to the control module 400. The control module 400 controls the operation of the exhaust fans 150, which expel the gas to be tested from inside the enclosure 100, thus allowing for the circulation of the gas and monitoring the hydrogen concentration trend. In other words, the gas to be tested can flow into the enclosure 100 through the vents 110 and then out through the exhaust fans 150.

[0097] It should be noted that, referring to Figures 1 to 3 In some embodiments of the present invention, a portable hydrogen sensing device based on quartz enhancement technology further includes a separator 160 and a battery 170.

[0098] The partition 160 is horizontally positioned inside the housing 100. The battery 170 is positioned below the partition 160 and installed at the bottom of the housing 100. The height of the vent 110 is the same as the height from the partition 160 to the bottom of the housing 100, in order to dissipate heat from the battery 170. The exhaust fan 150, control module 400, light source excitation module 300, temperature compensator, acoustic detection module, QEPAS chamber 200, and phase-locked amplifier module 500 are all positioned above the partition 160. By horizontally positioning the partition 160, the light source excitation module 300 can horizontally emit modulated infrared light.

[0099] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A portable hydrogen sensing device based on quartz enhancement technology, characterized in that, Includes: enclosure, control module, light source excitation module, acoustic detection module, QEPAS chamber and lock-in amplifier module; The control module, light source excitation module, QEPAS chamber, and lock-in amplification module are all located inside the enclosure. The acoustic detection module is located in the QEPAS chamber. The control module is connected to the light source excitation module and the lock-in amplification module respectively. The acoustic detection module is connected to the lock-in amplification module. Ventilation openings are provided at the bottom of both sides of the enclosure. The gas to be tested enters the interior of the enclosure through the ventilation openings to enter the QEPAS chamber. The control module outputs a modulation signal to the light source excitation module, which emits modulated infrared light according to the modulation signal and horizontally directs the modulated infrared light into the QEPAS gas chamber. In the QEPAS gas chamber, the modulated infrared light is used to pump water vapor in the gas to be tested as a pump gas to generate a photoacoustic effect. The acoustic detection module is used to detect the gas to be tested based on the photoacoustic effect and output a detection signal. The lock-in amplifier module is used to amplify the detection signal and transmit it to the control module. The control module calculates the hydrogen concentration in the gas to be tested based on the amplified detection signal. The QEPAS air chamber includes: a shell, a first transparent mirror, a second transparent mirror, and an H-shaped resonant cavity; The housing has an internal air chamber, the light source excitation module is located at one end of the air chamber, a fixing member is located in the middle of the air chamber, the H-shaped resonant cavity is mounted on the fixing member, the first light-transmitting mirror is located on both sides of the H-shaped resonant cavity, and the second light-transmitting mirror is located at the other end of the air chamber. The H-type resonant cavity includes: a first buffer cavity, a second buffer cavity, and a slit tube; The slit tube has a detection port in the center of both sides. One side of the first buffer chamber is connected to the first light-transmitting mirror, and the other side of the first buffer chamber is connected to one end of the slit tube. One side of the second buffer chamber is connected to the other end of the slit tube, and the other side of the second buffer chamber is connected to the first light-transmitting mirror. The modulated infrared light passes through the first light-transmitting mirror and horizontally enters the first buffer cavity, passes through the slit tube, and exits horizontally from the second buffer cavity through the first light-transmitting mirror to the second light-transmitting mirror.

2. The portable hydrogen sensing device based on quartz enhancement technology according to claim 1, characterized in that, A ventilation pipe is provided on one side of the housing, and the ventilation pipe is connected to the gas chamber. The gas to be tested enters the gas chamber through the ventilation pipe.

3. A portable hydrogen sensing device based on quartz enhancement technology according to claim 1, characterized in that, The acoustic detection module includes: a quartz tuning fork and a transimpedance amplifier; The quartz tuning fork is connected to a transimpedance amplifier. The quartz tuning fork is equipped with a piezoelectric crystal. The transimpedance amplifier is located at the top of the housing. The top of the housing is equipped with a detection channel. The fork arm of the quartz tuning fork passes through the detection channel and is inserted into the air chamber. The slit tube passes through the gap between the forks of the quartz tuning fork, and the forks of the quartz tuning fork are perpendicular to the slit tube, so that the tips of the forks of the quartz tuning fork face the detection port. The modulated infrared light passes through the slit tube, and according to the photoacoustic effect, the quartz tuning fork generates an oscillation decay signal. The piezoelectric crystal converts the oscillation decay signal into a current signal, and the transimpedance amplifier outputs the detection signal based on the current signal.

4. A portable hydrogen sensing device based on quartz enhancement technology according to claim 1, characterized in that, Also includes: Temperature and humidity compensator; The temperature and humidity compensator is connected to the light source excitation module. The temperature and humidity compensator is used to acquire the current temperature and humidity information, process the temperature and humidity information, and output a compensation signal to the light source excitation module.

5. A portable hydrogen sensing device based on quartz enhancement technology according to claim 4, characterized in that, The light source excitation module includes: a DFB laser and a laser driving unit; The input terminal of the laser driving unit is connected to the control module, and the DFB laser is connected to the output terminal of the laser driving unit. The laser driving unit outputs a driving signal to the DFB laser according to the modulation signal and the compensation signal, and the DFB laser emits modulated infrared light according to the driving signal.

6. A portable hydrogen sensing device based on quartz enhancement technology according to claim 1, characterized in that, Also includes: Warning lights and buzzers; Both the warning light and the buzzer are connected to the control module. The warning light is located on the top of the enclosure. When the hydrogen concentration is higher than the set concentration threshold, the control module controls both the warning light and the buzzer to respond and issue a warning signal.

7. A portable hydrogen sensing device based on quartz enhancement technology according to claim 1, characterized in that, Also includes: Handle and fixing components; The handle is located on the top of the box, and the fixing component is located on one side of the box. The fixing component is used to fix the installation position of the box.

8. A portable hydrogen sensing device based on quartz enhancement technology according to claim 6, characterized in that, Also includes: Human-computer interaction module; The human-machine interaction module is connected to the control module. The human-machine interaction module is used to acquire user commands and display hydrogen concentration. According to the user commands, the control module controls the warning light and buzzer to stop responding.

9. A portable hydrogen sensing device based on quartz enhancement technology according to claim 1, characterized in that, Also includes: Exhaust fan; The exhaust fans are located on the top of both sides of the housing and are connected to the control module.

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