Bracelet type hydrogen detection device and detection method

Abstract

The invention relates to the technical field of hydrogen detection, and provides a bracelet type hydrogen detection device and method, the device comprises a bracelet shell and a flexible circuit board arranged in the shell, and the flexible circuit board is provided with a rigid patch area. And the micro thermal conductivity detector and the Knudsen pump are both mounted on the rigid patch, are electrically connected and are respectively used for detecting the hydrogen concentration and actively pumping gas. The connecting member is made of a flexible thermal insulation material, is connected between the pump and the detector, and is used for air path communication and thermal isolation. The alarm module is arranged on the flexible circuit board and used for giving an alarm when the concentration exceeds a threshold value. According to the device, the micro thermal conductivity detector, the Knudsen pump and the connecting component are integrated on the bracelet, and all the components work cooperatively, so that the hydrogen detection function is integrated into bracelet type equipment; the gas flow path stability, the environment anti-interference performance and the long-term mechanical reliability of the whole structure of the detection unit are difficult to guarantee at the same time under the dynamic bending working condition.

Description

Technical Field

[0001] This application relates to the field of hydrogen detection technology, and in particular to a wristband-type hydrogen detection device and detection method. Background Technology

[0002] Against the backdrop of the rapid development of the hydrogen energy industry, the safety of hydrogen across its entire industrial chain, as a highly efficient and clean energy source, is receiving increasing attention. Hydrogen has an extremely wide explosive limit range and extremely low ignition energy, making it highly susceptible to combustion or explosion in the event of a leak. Therefore, real-time and reliable monitoring of hydrogen leaks is crucial to ensuring the safe operation of related industries. However, current mainstream hydrogen detection technologies, from their application forms to their core principles, still face a series of challenges in meeting the demands for portable, wearable, and highly reliable monitoring.

[0003] In terms of application, existing hydrogen detection devices are mainly divided into fixed, portable, and mobile types. While fixed devices can achieve 24-hour continuous monitoring, their installation and construction are complex, initial construction costs are high, and their coverage area is fixed, making them difficult to adapt to temporary operations or dynamically changing site environments. Portable devices, although offering greater flexibility, are mostly handheld, requiring the user to operate with one hand in practice. This not only fails to provide continuous, close-contact monitoring but may also introduce new safety hazards due to operational limitations. Mobile devices, mounted on vehicles or other platforms, suffer from high costs and are heavily restricted by terrain, making them difficult to widely adopt as personal protective equipment.

[0004] In terms of core detection principles, currently widely used sensors are mainly based on chemical reactions between gases and sensitive materials, each with its inherent limitations. For example, electrochemical sensors typically have a narrow detection range and are prone to saturation failure in high-concentration hydrogen environments; semiconductor sensors require high temperatures to operate, which accelerates material aging and leads to a short lifespan; while catalytic combustion sensors are highly dependent on an oxygen-rich environment, cannot operate in oxygen-free conditions, and face the risk of catalyst poisoning or even burnout in high-concentration hydrogen environments. These chemically based sensors face bottlenecks in achieving long lifespan, wide measurement range, and high safety.

[0005] Furthermore, when attempting to miniaturize hydrogen detection functionality and integrate it into wearable devices such as wristbands, existing technologies face a fundamental integration challenge. Traditional high-precision gas detection typically relies on a detection unit that requires a stable airflow environment and constant temperature operation, along with an auxiliary system to provide that stable airflow. However, under the dynamic bending conditions of frequent wrist movements, how to construct a stable, sealed, and interference-resistant gas flow path and environment for the detection unit within an extremely miniaturized space, while ensuring the overall integrated structure maintains functional reliability under long-term mechanical deformation, is an obstacle that existing technologies struggle to overcome. This contradiction severely restricts the development of truly reliable wearable hydrogen detection devices suitable for long-term, close-fitting monitoring. Summary of the Invention

[0006] In view of this, this application proposes a wristband-type hydrogen detection device and detection method to solve the technical problem that when integrating hydrogen detection function into a wristband-type wearable device, it is difficult to simultaneously ensure the stability of the gas flow path of the detection unit, the environmental anti-interference ability, and the long-term mechanical reliability of the overall structure under dynamic bending conditions.

[0007] The technical solution of this application is implemented as follows: In a first aspect, this application provides a wristband-type hydrogen detection device, comprising: Bracelet housing; A flexible circuit board is disposed inside the wristband housing, and a rigid patch area is provided on the flexible circuit board; A miniature thermal conductivity detector is disposed on the rigid patch area of ​​the flexible circuit board and electrically connected to the flexible circuit board for detecting hydrogen concentration; A Knudsen pump is disposed on the rigid patch area of ​​the flexible circuit board and electrically connected to the flexible circuit board, for actively pumping ambient gas to the miniature thermal conductivity detector. A connecting member, made of flexible thermal insulation material, connects the outlet of the Knudsen pump and the inlet of the miniature thermal conductivity detector to connect the air path and provide thermal insulation; and An alarm module is mounted on and electrically connected to the flexible circuit board, and is used to issue an alarm when the hydrogen concentration reaches a threshold.

[0008] Based on the above technical solution, preferably, the Knudsen pump includes: The pump body has an air inlet and an air outlet; A heat dissipation component is fitted onto the side of the pump body corresponding to the air inlet; A pumping functional layer is disposed within the pump body and located on the gas flow channel between the air inlet and the air outlet; A heating element is disposed within the pump body and electrically connected to the flexible circuit board; The heating element is used to heat the pumping functional layer and, together with the heat sink, forms a temperature gradient on both sides of the pumping functional layer to drive the gas from the inlet to the outlet.

[0009] Based on the above technical solution, preferably, the pump body further includes a first glass chip, a second glass chip, and a third glass chip stacked together. Microchannels are etched inside the first glass chip, the second glass chip, and the third glass chip. The microchannels together form a gas flow channel from the air inlet to the air outlet. The pumping functional layer is bonded between the first glass chip and the second glass chip. The heating element is fixedly disposed between the second glass chip and the third glass chip.

[0010] Based on the above technical solution, preferably, the Knudsen pump further includes an air inlet pipe, one end of which passes through the heat sink and is connected to the air inlet on the pump body, and the other end extends to the outside of the wristband housing. A primary coarse filter and a secondary fine filter are sequentially arranged inside the air inlet pipe along the air intake direction.

[0011] Based on the above technical solution, preferably, the pumping functional layer is an integral porous silicon structure with nanoscale through-holes, which is bonded between the first glass chip and the second glass chip, and the nanoscale through-holes constitute part of the gas flow channel.

[0012] Based on the above technical solution, preferably, the connecting member includes: The connecting body is made of flexible thermal insulation material; A first flow channel and a second flow channel are formed within the connecting body. The inlet of the first flow channel is used to connect to the outlet of the Knudsen pump, and the outlet of the second flow channel is used to connect to the inlet of the miniature thermal conductivity detector; and A flexible microtube is embedded within the connecting body and connects the first flow channel to the second flow channel.

[0013] Based on the above technical solution, preferably, the miniature thermal conductivity detector includes: The encapsulation housing has an air inlet and an air outlet, and the air inlet of the encapsulation housing is in fluid communication with the air outlet of the Knudsen pump through the connecting member; A reference cell, which is sealed within the encapsulation housing and filled with a reference gas; The detection pool, disposed within the encapsulation housing, is connected to the second flow channel outlet of the connecting member; and Two thermistors are respectively disposed in the reference cell and the detection cell; wherein the two thermistors are used to connect to a Wheatstone bridge circuit to detect changes in the thermal conductivity of the gas in the detection cell.

[0014] Based on the above technical solution, preferably, the reference gas filled in the reference pool is pure air.

[0015] Based on the above technical solution, preferably, the flexible circuit board is a structure combining a flexible PCB substrate and a partially rigid patch, and a microcontroller and a signal conditioning module are integrated thereon. The microcontroller and signal conditioning module are used to process the signal of the miniature thermal conductivity detector and control the alarm module and the Knudsen pump. The alarm module includes a micro-flat vibration motor, a micro-surface buzzer, and a surface-mount LED. The micro-surface buzzer and the micro-flat vibration motor are disposed on the rigid surface-mount, and the surface-mount LED is disposed in the flexible area of ​​the flexible PCB substrate.

[0016] Secondly, this application discloses a detection method for a wristband-type hydrogen detection device, which uses the wristband-type hydrogen detection device described in the first aspect, and includes the following steps: The Knudsen pump and the miniature thermal conductivity detector are activated, and the ambient gas is pumped into the detection pool through the Knudsen pump; The miniature thermal conductivity detector is initialized and calibrated to eliminate the Wheatstone bridge bias voltage caused by the initial composition difference between the reference gas and the ambient gas. The ambient gas is continuously pumped into the detection cell through the Knudsen pump, and the change in thermal conductivity of the gas in the detection cell is detected by the miniature thermal conductivity detector. When the change in thermal conductivity indicates that the hydrogen concentration in the environment has reached or exceeded a predetermined concentration threshold, the alarm module is controlled to issue an alarm.

[0017] This application has the following advantages over the prior art: 1) The wristband-type hydrogen detection device disclosed in this application achieves close-fitting monitoring through a wearable wristband shell. It utilizes a combination of flexible circuit boards and rigid patches to maintain the stability of core components under dynamic bending. A detector based on thermal conductivity principles enables safe and wide-range detection. An integrated Knudsen pump provides stable and active gas sampling. Flexible, heat-insulating connection components are designed to ensure reliable gas path connectivity and thermal interference isolation. An alarm module provides timely warnings. These components work together to solve the technical problem of simultaneously ensuring the stability of the gas flow path, environmental interference resistance, and long-term mechanical reliability of the overall structure when integrating hydrogen detection functionality into a wristband-type device under dynamic bending conditions.

[0018] 2) The Knudsen pump disclosed in this application establishes and maintains a stable temperature gradient on both sides of the pumping functional layer by constructing a flow channel through the pump body and utilizing a combination of active heating by heating elements and active cooling by heat sinks. This temperature gradient drives the gas to flow continuously and stably from the pump inlet to the outlet based on the thermomolecular flow effect, thereby providing active, controllable gas sampling without moving parts for subsequent miniature thermal conductivity detectors. This structure is compact and reliable, making it ideal for integration into wearable wristband-type detection devices with extremely high requirements for wrist movement adaptability, space constraints, and reliability.

[0019] 3) By incorporating multiple layers of glass chips within the pump body, the synergistic effect of each layer creates and maintains a stable, uniform, and localized temperature field within the micro-pump. This structure ensures, on the one hand, the efficient and reliable formation of the temperature gradient required for directional pumping of the driving gas, thereby achieving stable airflow output; on the other hand, it effectively isolates the thermal crosstalk of the pump body's own operating heat to the downstream sensitive detection unit, ensuring detection accuracy.

[0020] 4) By integrating two-stage filters within the intake pipe, progressive purification and protection of the inhaled gas are achieved. The coarse filter ensures the physical unobstructed flow of the gas, while the fine filter improves the chemical purity of the gas and controls humidity. Working together, these two filters significantly reduce the risk of contamination, interference, and damage to the downstream micro-thermal conductivity detector from complex environmental components. From the perspective of ensuring gas source quality, this greatly improves the accuracy and stability of the detection, as well as the long-term reliability of the entire sensor system in complex industrial environments.

[0021] 5) This application uses a connecting body made of flexible thermal insulation material, a first and second flow channel with precise internal docking, and an embedded flexible microtube to form a connecting component. Physically, it realizes a reliable air path connection between the Knudsen pump and the micro thermal conductivity detector. Thermally, it effectively isolates the interference of pump body heat on the detector. Mechanically, it ensures the long-term reliability and airtightness of the entire connecting structure under dynamic bending conditions.

[0022] 6) By setting up a miniature thermal conductivity detector, utilizing a differential design between the reference and detection cells, and based on a Wheatstone bridge detection circuit composed of two thermistors, a highly sensitive and interference-resistant gas detection scheme was achieved. This scheme converts the difficult-to-measure gas concentration change into a thermistor temperature difference caused by the difference in gas thermal conductivity, and further into an easily measurable electrical signal difference. This physical detection principle does not rely on chemical reactions, fundamentally avoiding problems such as electrode consumption and catalyst poisoning, and achieving wide-range, long-life, and safe detection. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a three-dimensional structural diagram of the wristband-type hydrogen detection device disclosed in the embodiments of this application; Figure 2 This is a schematic plan view of the assembly structure of the flexible circuit board, miniature thermal conductivity detector, Knudsen pump, connecting components and alarm module disclosed in the embodiments of this application. Figure 3 This is a three-dimensional structural diagram of the miniature thermal conductivity detector and Knudsen pump disclosed in the embodiments of this application; Figure 4 This is a three-dimensional structural diagram of the connecting member disclosed in the embodiments of this application; Figure label: 1. Wristband housing; 2. Flexible circuit board; 3. Miniature thermal conductivity detector; 4. Knudsen pump; 5. Connecting component; 6. Alarm module; 40. Pump body; 41. Heat sink; 42. Pumping functional layer; 43. Heating element; 44. First glass chip; 45. Second glass chip; 46. Third glass chip; L. Microchannel; 47. Air inlet pipe; 48. Primary coarse filter; 49. Secondary fine filter; 51. Connecting body; 52. First flow channel; 53. Second flow channel; 54. Flexible microtube; 31. Encapsulation housing; 32. Reference cell; 33. Detection cell; 34. Thermistor; 21. Flexible PCB substrate; 22. Rigid patch; 23. Microcontroller; 24. Signal conditioning module; 61. Micro-flat vibration motor; 62. Miniature patch buzzer; 63. Patch LED. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0027] In the description of the embodiments of this application, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0029] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0030] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0031] like Figure 1 As shown, combined with Figure 2-4The first embodiment of this application discloses a wristband-type hydrogen detection device, including a wristband housing 1, a flexible circuit board 2, a miniature thermal conductivity detector 3, a Knudsen pump 4, a connecting component 5, and an alarm module 6.

[0032] The wristband housing 1 constitutes the main body of the device, and its ring shape is adapted to fit the wrist. The housing adopts a wearable design, which allows the entire detection device to be worn close to the wrist of the operator, thereby freeing up the hands and realizing all-weather, mobile, continuous monitoring of hydrogen, greatly expanding the flexibility and applicable scenarios of the detection operation.

[0033] The flexible circuit board 2 is disposed inside the wristband housing 1, serving as the electrical and structural integration foundation of the entire device. The flexible circuit board 2 has specific rigid patch areas 22. The flexible substrate allows it to conform to the bending deformation of the wrist, ensuring wearing comfort; while the locally positioned rigid patch areas 22 provide a stable mounting platform for core functional components requiring high installation accuracy and stability, effectively preventing component displacement or connection failure due to substrate deformation under dynamic bending conditions, thus ensuring the long-term mechanical reliability of the overall structure.

[0034] The miniature thermal conductivity detector 3 is disposed on the rigid patch 22 area of ​​the flexible circuit board 2 and electrically connected to the flexible circuit board 2. It serves as the core sensing unit for detecting the hydrogen concentration in the environment. This detector operates based on the significant difference in thermal conductivity between hydrogen and air, belonging to the physical detection principle. When hydrogen-containing gas flows through the detector, it causes changes in the temperature and resistance of its internal thermistor, thereby outputting a corresponding electrical signal. Compared to sensors based on chemical reactions (such as electrochemistry and catalytic combustion), this principle does not require the consumption of electrodes or catalysts, does not rely on an oxygen environment, and poses no risk of open flame, thus fundamentally achieving a wider detection range, higher safety in use, and a longer theoretical working life.

[0035] The Knudsen pump 4 is disposed on the same rigid patch 22 area of ​​the flexible circuit board 2 and electrically connected to the flexible circuit board 2. It serves as an active sampling system to continuously and stably pump ambient gas to the miniature thermal conductivity detector 3. This pump operates based on a thermally driven principle and has no moving mechanical parts during operation. Through active pumping, it provides a stable and controllable gas flow rate to the miniature thermal conductivity detector 3, overcoming the shortcomings of slow speed and unstable gas flow in traditional passive diffusion sampling methods. This ensures rapid gas replacement and response speed within the detection unit, guaranteeing the stability of the gas flow path in the detection unit from the gas source perspective.

[0036] The connecting component 5 is made of flexible thermal insulation material and connects the outlet of the Knudsen pump 4 to the inlet of the miniature thermal conductivity detector 3. This component first serves as a gas passage, transmitting the gas to be tested from the Knudsen pump 4 to the detector without leakage. Secondly, due to the low thermal conductivity of its material, this component, while physically connecting the two core components, also forms an effective thermal isolation barrier between them. This significantly prevents the heat generated by the Knudsen pump 4 during operation from being transferred to the temperature-sensitive miniature thermal conductivity detector 3, thereby ensuring the temperature stability of the detector's operating environment and enhancing its resistance to thermal interference.

[0037] The alarm module 6 is mounted on and electrically connected to the flexible circuit board 2. It receives signals from the miniature thermal conductivity detector 3 and immediately triggers an alarm when the signal processing unit determines that the hydrogen concentration has reached a preset safety threshold. The module's function is to provide the wearer with clear and timely danger warnings, prompting them to take emergency measures, thus completing a full safety loop from detection to warning.

[0038] The wristband-type hydrogen detection device disclosed in this application achieves close-fitting monitoring through a wearable wristband shell 1. It utilizes a combination of a flexible circuit board 2 and a rigid patch 22 to maintain the stability of core components under dynamic bending. A detector based on thermal conductivity principles achieves safe and wide-range detection. An integrated Knudsen pump 4 provides stable and active gas sampling. A flexible, heat-insulating connection component 5 is designed to ensure reliable gas path connectivity and thermal interference isolation. An alarm module 6 is equipped for timely warnings. These components work together to solve the technical problems encountered when integrating hydrogen detection functionality into a wristband-type device, namely, the difficulty in simultaneously ensuring the stability of the gas flow path of the detection unit, environmental interference resistance, and the long-term mechanical reliability of the overall structure under dynamic bending conditions.

[0039] In some embodiments, this application discloses the specific structure of a Knudsen pump 4, which includes a pump body 40, a heat sink 41, a pumping functional layer 42, and a heating element 43.

[0040] The pump body 40 forms the main structural frame of the pump, with an inlet and an outlet at each end. The inlet receives gas from the external environment, while the outlet outputs the pumped gas to the subsequent connecting component 5 and the detection unit. The design of the pump body 40 ensures that the gas can be confined within a specific flow channel, providing a basic structural channel for the pumping function.

[0041] The heat sink 41 is fitted onto the side of the pump body 40 corresponding to the air inlet. The heat sink 41 is made of a material with good thermal conductivity, such as an aluminum profile with fins. The function of the heat sink 41 is to actively dissipate heat accumulated or conducted from the air inlet side of the pump body 40 into the surrounding air by increasing the heat exchange area with the external environment of the pump body 40. The purpose of the heat sink 41 is to actively create a relatively low-temperature region in terms of physical structure, which is one of the keys to forming a stable temperature gradient with the internal heating area of ​​the pump body 40.

[0042] The pumping functional layer 42 is disposed within the pump body 40, and its physical position is located on the gas flow channel between the air inlet and the air outlet, which ensures that all pumped gas must flow through this layer. In this embodiment, the pumping functional layer 42 is made of a material with a nanoscale or microscale porous structure. Its core function is that when there is a temperature difference on both sides of the porous structure, the movement of gas molecules within the pores will generate a directional net flow rate, i.e., based on the Knudsen effect or the principle of heat escape, thereby realizing active gas pumping without mechanical moving parts. It is a direct functional carrier for converting thermal energy into gas kinetic energy.

[0043] Heating element 43 is also disposed within the pump body 40 and electrically connected to the flexible circuit board 2. The function of heating element 43 is to generate heat when energized, and the heat energy generated by heating element 43 can be effectively transferred to the pumping functional layer 42, thereby heating a specific area thereon. Through the power supply and control of the flexible circuit board 2, the power of heating element 43 can be adjusted, thereby precisely controlling the heating temperature and pumping airflow rate of the pumping functional layer 42.

[0044] The heating element 43 is used to heat the pumping functional layer 42, and works in conjunction with the heat sink 41 to form a temperature gradient on both sides of the pumping functional layer 42. Specifically, the heating element 43 continuously heats one side of the pumping functional layer 42, while the heat sink 41 located on the inlet side strives to maintain the corresponding other side of the pumping functional layer 42 at a temperature close to ambient temperature, thereby establishing a stable temperature gradient from the cold side to the hot side along the airflow direction throughout the pumping functional layer 42. This temperature gradient is the fundamental physical driving force that drives the gas to flow directionally from the inlet (cold end) to the outlet (hot end) of the pump body 40.

[0045] The Knudsen pump 4 disclosed in this application constructs a flow channel through the pump body 40 and establishes and maintains a stable temperature gradient on both sides of the pumping functional layer 42 by combining active heating with heating element 43 and passive cooling with heat sink 41. This temperature gradient drives the gas to flow continuously and stably from the pump inlet to the outlet based on the thermomolecular flow effect, thereby providing active, controllable gas sampling without moving parts for the subsequent miniature thermal conductivity detector 3. This structure is compact and reliable, making it ideal for integration into wearable wristband-type detection devices with extremely high requirements for wrist movement adaptability, space constraints, and reliability.

[0046] In some embodiments, the pump body 40 further includes a first glass chip 44, a second glass chip 45, and a third glass chip 46 stacked together.

[0047] In this embodiment, borosilicate glass is used as the chip material, which has a moderately low thermal conductivity. This characteristic helps reduce unnecessary heat loss, thereby facilitating the formation and maintenance of a stable temperature gradient within the pump body 40, providing an ideal basic material for heat-driven pumping principles. Simultaneously, the glass chip itself is a good insulator and thermal insulator. When placed in a suitable position within the pump, it can effectively achieve thermal isolation between devices, prevent unnecessary thermal crosstalk, and ensure the stability of the temperature field in the core functional areas.

[0048] The interiors of the first glass chip 44, the second glass chip 45, and the third glass chip 46 are all etched with precise microchannels L using mature microfabrication technology. This microfabrication process can be wet or dry etching. These microchannels L, located within each chip layer, are aligned and connected after the chips are stacked and bonded, collectively forming a complete, sealed gas flow channel extending from the inlet to the outlet of the pump body 40.

[0049] The pumping functional layer 42 is bonded between the first glass chip 44 and the second glass chip 45. This design has several important functions: First, from a process implementation perspective, placing the first glass chip 44 between the pumping functional layer 42 and the outer heat sink 41 avoids the process difficulties of directly bonding dissimilar materials with high reliability, thus improving manufacturing feasibility. Second, and more importantly, the first glass chip 44, as a stable thermal buffer and temperature homogenization layer, can isolate the non-uniform or unstable temperature field that may be generated by the metal heat sink due to factors such as fluctuations in ambient airflow, thereby ensuring that the temperature transferred to the cold side (inlet side) of the pumping functional layer 42 is uniform and stable. This is a key prerequisite for maintaining a precise temperature gradient on both sides of the functional layer.

[0050] A heating element 43 is fixedly disposed between the second glass chip 45 and the third glass chip 46. In this embodiment, the heating element 43 is a Ti / Pt thermistor 34, which is fixed to the surface of the second glass chip 45. The second glass chip 45, as a uniform thermally conductive substrate, can uniformly conduct the heat generated by the heating element 43 to the hot side (outlet side) of the pumping functional layer 42 bonded to it, avoiding the problem of uneven temperature field caused by local overheating at the heating point, thereby establishing a uniform and controllable high-temperature region on the hot side of the functional layer. The third glass chip 46 is located between the heating element 43 and the outlet of the pump body 40. Utilizing the low thermal conductivity of the glass material, it can effectively block the excessive transfer of heat generated by the heating element 43 during operation to the downstream of the pump body 40 and the connecting member 5. This design avoids thermal crosstalk caused by the working heat of the pump body 40 itself to the downstream gas path and the finally connected temperature-sensitive miniature thermal conductivity detector 3, thereby ensuring the environmental thermal stability of the detection end and guaranteeing the detection accuracy.

[0051] By incorporating multiple layers of glass chips within the pump body 40, the synergistic effect of each layer creates and maintains a stable, uniform, and localized temperature field within the micro-pump body 40. This structure ensures, on the one hand, the efficient and reliable formation of the temperature gradient required for directional pumping of the driving gas, thereby achieving stable airflow output; on the other hand, it effectively isolates the thermal crosstalk of the pump body 40's own operating heat to the downstream sensitive detection unit, ensuring detection accuracy.

[0052] In some embodiments, the Knudsen pump 4 further includes an air inlet pipe 47, one end of which passes through the heat sink 41 and connects to the air inlet on the pump body 40, thus forming an inlet channel for the gas flow from the outside of the pump to the inside of the pump body 40. The other end of the air inlet pipe 47 extends to the outside of the wristband housing 1. This design allows the end of the air inlet pipe 47 to be directly exposed to the ambient air to be monitored, serving as the physical interface for the entire device to actively collect ambient gas samples. Its function is to establish a controlled sampling path, ensuring that the ambient gas can be directed and efficiently guided to the air inlet of the Knudsen pump 4, providing a gas source for subsequent active pumping and detection.

[0053] The air intake pipe 47 contains a primary coarse filter 48 and a secondary fine filter 49 arranged sequentially along the air intake direction, forming a multi-stage filtration system. When ambient gas is drawn in by the Knudsen pump 4, it first flows through the primary coarse filter 48. The primary coarse filter 48 mainly uses a material with relatively large mesh sizes, such as a miniature stainless steel woven mesh. Its function is to perform primary physical interception, filtering out larger particles such as dust, pollen, and fibers suspended in the air. This prevents large particles of impurities from directly entering and potentially clogging the subsequent precision microchannels L or contamination sensors.

[0054] The gas, after coarse filtration, then passes through a secondary fine filter 49, which performs even finer filtration, going beyond simple particulate interception. This secondary fine filter includes a polytetrafluoroethylene (PTFE) membrane with a microporous structure and / or an activated carbon filter. The PTFE membrane further filters out finer particles, and its hydrophobic properties also provide dehumidification, effectively reducing interference from gaseous water, water mist, and tiny droplets in subsequent detection. The activated carbon filter, utilizing its large specific surface area and abundant micropores, selectively adsorbs gaseous interfering substances such as organic vapors with larger molecular weights and higher boiling points from the air, primarily through physical adsorption, while adsorbing almost no small molecules of non-polar hydrogen. This combined design ensures that the gas entering the detection system is as clean and dry as possible, and that the main interfering components are pre-removed.

[0055] By integrating two-stage filters within the intake pipe 47, progressive purification and protection of the inhaled gas are achieved. The coarse filter ensures the physical unobstructed flow of the gas, while the fine filter improves the chemical purity of the gas and controls humidity. Working together, these two filters significantly reduce the risk of contamination, interference, and damage to the downstream miniature thermal conductivity detector 3 caused by complex environmental components. From the perspective of ensuring gas source quality, this greatly improves the accuracy and stability of the detection, as well as the long-term reliability of the entire sensor system in complex industrial environments.

[0056] In some embodiments, the pumping functional layer 42 is an integral porous silicon structure with nanoscale through-holes, which is bonded between the first glass chip 44 and the second glass chip 45, and the nanoscale through-holes constitute part of the gas flow channel.

[0057] In this embodiment, the monolithic porous silicon structure means that the pumping functional layer 42 is not composed of multiple separate porous sheets stacked together, but rather a monolithic, integrated silicon material structure with a continuous silicon framework and uniform pores, formed internally through micromachining or specific processes. This monolithic design endows it with excellent mechanical structural stability and thermal conductivity consistency, avoiding the problems of uneven thermal resistance or bonding failure that may arise from interlayer interfaces.

[0058] These channels, spanning the entire silicon structure, have nanoscale pore sizes. This ensures that the mean free path of gas molecules within the channels is comparable to or larger than the channel size, thus satisfying the fundamental operating conditions of the Knudsen pump based on molecular flow effects. This allows for the effective driving of directional net gas flow when a temperature gradient is applied across the channels. Furthermore, the design incorporates a large number of these nanoscale interconnected channels throughout the structure, which work in parallel to form a high-throughput gas flow path from the inlet to the outlet. This design cleverly resolves the limitation of flow rate in a single microchannel, significantly increasing the total gas flow rate that can pass through and be transmitted to the subsequent detection element per unit time without increasing the device's planar size, thereby improving the overall detection system's inlet efficiency and response speed.

[0059] In some embodiments, this application illustrates a specific structural configuration of the connecting member 5.

[0060] Specifically, the connecting component 5 includes a connecting body 51, which is made of a flexible thermal insulation material. In specific implementations, the connecting body 51 can be made of high-performance polymers such as polyimide (PI). Such materials have excellent flexibility and can adapt to repeated bending deformation when worn on the wrist; at the same time, they have extremely low thermal conductivity and are excellent thermal insulators. The core purpose of using a flexible thermal insulation material as the body is to simultaneously achieve the three functions of mechanical connection, adaptability to bending, and efficient thermal insulation when physically connecting the two core heating / temperature sensing elements, the Knudsen pump 4 and the miniature thermal conductivity detector 3.

[0061] Within the connecting body 51, a first flow channel 52 and a second flow channel 53 are formed. The inlet of the first flow channel 52 is configured to connect to the outlet of the Knudsen pump 4, and the outlet of the second flow channel 53 is configured to connect to the inlet of the micro thermal conductivity detector 3. These flow channels can be precisely fabricated within a flexible thermal insulation material substrate using micromachining techniques, such as reactive ion etching. Their function is to construct bridges and docking channels for gas transport. The first flow channel 52 is responsible for smoothly receiving the accelerated airflow from the outlet of the Knudsen pump 4, and the second flow channel 53 is responsible for smoothly guiding the airflow and injecting it into the inlet of the detection cell 33 of the micro thermal conductivity detector 3.

[0062] The connecting member 5 further includes a flexible microtube 54, which is embedded within the connecting body 51 and connects the first flow channel 52 with the second flow channel 53. The flexible microtube 54 is a gas transmission channel and is made of materials such as polytetrafluoroethylene (PTFE) that have both extremely low thermal conductivity and excellent flexibility.

[0063] The flexible microtube 54 serves several purposes: First, it acts as the final gas flow channel, completing the gas path connection from the pump to the detector. Second, utilizing its extremely low thermal conductivity, similar to that of the connecting body 51, it forms a thermal barrier with the body, greatly blocking the direct heat conduction from the Knudsen pump 4 to the temperature-sensitive micro thermal conductivity detector 3, effectively solving the problem of thermal crosstalk within the small integrated space. Third, its flexibility ensures that even when the entire bracelet bends due to wrist movement, this core gas path channel can deform accordingly without breaking or leaking, maintaining airtightness.

[0064] This application uses a connecting body 51 made of flexible thermal insulation material, first and second flow channels 53 with internal precision docking, and embedded flexible microtubes 54 to form a connecting component 5. Physically, it realizes a reliable air path connection between the Knudsen pump 4 and the micro thermal conductivity detector 3. Thermally, it effectively isolates the interference of the heat of the pump body 40 on the detector. Mechanically, it ensures the long-term reliability and airtightness of the entire connecting structure under dynamic bending conditions.

[0065] In some embodiments, this application illustrates a specific structural configuration of a miniature thermal conductivity detector 3.

[0066] Specifically, the miniature thermal conductivity detector 3 includes a housing 31, which has independent air inlet and outlet, forming a sealed chamber. The air inlet is fluidly connected to the outlet of the Knudsen pump 4 via the aforementioned connecting member 5, and the outlet is used to provide an outlet for discharging the gas after detection.

[0067] Within the encapsulation housing 31, a reference cell 32 is sealed. This reference cell 32 is permanently sealed after being filled with a pure gas of known composition during manufacturing, ensuring that its internal gas composition remains constant and no longer exchanges with the external environment. The core function of the reference cell 32 is to provide a stable and unchanging physical benchmark. The thermal conductivity of the gas sealed within it serves as a constant reference value for comparison with the gas flowing through the detection cell 33, whose composition may vary.

[0068] Alongside the reference cell 32, a detection cell 33 is also disposed within the encapsulation housing 31. This detection cell 33 is in fluid communication with the external environment through the housing's air inlet, thereby continuously receiving ambient gas samples actively pumped by the Knudsen pump 4. The detection cell 33 serves as a window for interaction with the environment under test, and the thermal conductivity of the gas inside changes with variations in the composition of the ambient gas, particularly the hydrogen concentration.

[0069] The miniature thermal conductivity detector 3 also includes two thermistors 34, which are respectively disposed inside the reference cell 32 and the detection cell 33. Thermistors 34 are elements extremely sensitive to temperature changes, and their resistance changes with their own temperature. These two thermistors 34 are designed to have highly consistent thermoelectric characteristics. They are used in a Wheatstone bridge circuit. In this circuit, the thermistors 34 in the reference cell 32 and the detection cell 33 are located in two adjacent arms of the bridge. When the thermal conductivity of the gases in both cells is the same, the heat exchange rate flowing through the thermistors 34 is consistent, their resistances are the same, the bridge is in equilibrium, and the output voltage is zero. When the thermal conductivity of the detection cell 33 increases due to the introduction of hydrogen gas (whose thermal conductivity is much higher than that of air), the heat dissipation conditions of the thermistors 34 in the detection cell 33 will be better than those in the reference cell 32, resulting in a temperature difference between the two and consequently, a difference in their resistance values. This tiny resistance difference will be detected by a highly sensitive Wheatstone bridge circuit and converted into a weak differential voltage signal.

[0070] By setting up a miniature thermal conductivity detector 3, utilizing the differential design of the reference cell 32 and the detection cell 33, and based on a Wheatstone bridge detection circuit composed of two thermistors 34, a highly sensitive and highly interference-resistant gas detection scheme is realized. This scheme converts the difficult-to-measure gas concentration change into a temperature difference in the thermistors 34 caused by the difference in gas thermal conductivity, and further converts this into an easily measurable electrical signal difference. This physical detection principle does not rely on chemical reactions, fundamentally avoiding problems such as electrode consumption and catalyst poisoning, and achieving wide-range, long-life, and safe detection.

[0071] In some embodiments, the reference gas filled in the reference pool 32 is specifically pure air. Specifically, during the manufacturing or initialization phase, purified clean air with known and stable composition is sealed and injected into the reference pool 32, permanently isolating it from the external environment, thereby forming a constant gaseous environment inside the reference pool 32.

[0072] Choosing pure air as the reference gas is based on a comprehensive consideration of its physicochemical properties and ease of access. First, pure air is mainly composed of nitrogen, oxygen, and small amounts of inert gases, and its thermal conductivity under normal environmental conditions is a stable and known physical constant. This provides a reliable and unchanging benchmark for the entire differential detection system.

[0073] In some embodiments, the flexible circuit board 2 is a structure combining a flexible PCB substrate 21 and locally rigid patches 22. This structure is optimized for wearable wristbands, with the flexible PCB substrate 21 as its main body, allowing it to naturally bend to conform to the contours of the wrist, thus ensuring a good fit and comfort, and avoiding the wrist discomfort and restriction of movement caused by purely rigid circuit boards. Simultaneously, rigid patches 22 are locally provided in key areas on the flexible substrate. These rigid patches 22 provide a robust and flat mounting platform for core functional components that require high installation accuracy, mechanical stability, or heat dissipation.

[0074] The flexible circuit board 2 also integrates a microcontroller 23 and a signal conditioning module 24. The microcontroller 23 executes the core control logic: it receives and processes the raw electrical signal from the miniature thermal conductivity detector 3 through the signal conditioning module 24, amplifying and filtering the signal, and executing algorithms such as temperature compensation, concentration calculation, and threshold judgment. Simultaneously, it generates control signals to drive and control the coordinated operation of the alarm module 6 and the Knudsen pump 4. The signal conditioning module 24 acts as a pre-processor, responsible for initially purifying and enhancing the weak analog signal output from the sensor to improve the signal-to-noise ratio, providing high-quality input for the microcontroller 23's accurate judgment. Their integration constitutes a complete closed loop of detection, processing, and control.

[0075] The alarm module 6 includes a micro-flat vibration motor 61, a miniature patch buzzer 62, and a patch LED 63, forming a multimodal alarm system. The micro-flat vibration motor 61 generates a strong tactile response, ensuring reliable alarm detection even in noisy or brightly lit environments; the miniature patch buzzer 62 provides an audible alarm; and the patch LED 63 provides a visual indication through light emission. This combination ensures that at least one alarm mode can effectively attract the wearer's attention in any complex industrial environment, greatly improving alarm reliability and personnel response speed.

[0076] In this embodiment, the miniature patch buzzer 62 and the micro-flat vibration motor 61 are mounted on the rigid patch 22. This is because the miniature patch buzzer 62 and the micro-flat vibration motor 61 will vibrate during operation or require stable support to efficiently transmit vibration. Mounting them on the rigid patch 22 can prevent the deformation of the flexible substrate from affecting their working efficiency or causing abnormal noise, thus ensuring the reliability and quality of alarm execution. The patch LED 63 is disposed in the flexible area of ​​the flexible PCB substrate 21. LEDs mainly provide static or flashing light signals, and the rigidity requirements of the mounting platform are relatively low. Arranging them in the flexible area is conducive to achieving a more flexible and uniform light distribution and indication design, while reducing the layout difficulty.

[0077] The second embodiment of this application also discloses a detection method for a wristband-type hydrogen detection device, including the following steps: The Knudsen pump 4 and the miniature thermal conductivity detector 3 are started, and the ambient gas is pumped into the detection pool 33 through the Knudsen pump 4.

[0078] The miniature thermal conductivity detector 3 is initialized and calibrated to eliminate the Wheatstone bridge bias voltage caused by the initial composition difference between the reference gas and the ambient gas.

[0079] In this step, Knudsen pump 4 pumps ambient air into detection cell 33, while reference cell 32 is already sealed with pure air. Due to manufacturing tolerances and minor fluctuations in the background gas composition, even though both cells are initially filled with air, the output of the Wheatstone bridge is typically not absolutely zero; an inherent bias voltage exists. Microcontroller 23 acquires this initial voltage value through signal conditioning module 24, records it, and compensates for it to zero. The core purpose of this step is to eliminate the inherent static error of the system and accurately calibrate the detected electrical zero point to an air reference, thus laying the foundation for subsequent accurate detection of minor changes in thermal conductivity caused by hydrogen.

[0080] The ambient gas is continuously pumped into the detection pool 33 by the Knudsen pump 4, and the change in thermal conductivity of the gas in the detection pool 33 is detected by the miniature thermal conductivity detector 3.

[0081] The miniature thermal conductivity detector 3 operates continuously, with its internal Wheatstone bridge constantly comparing the resistance difference of the thermistor 34 in the reference cell 32 and the detection cell 33. If hydrogen gas mixes into the ambient air, its thermal conductivity is much higher than that of air, causing a sudden increase in the heat dissipation capacity of the gas flowing through the thermistor 34 in the detection cell 33. This results in a drop in the temperature and a change in the resistance of the thermistor 34, disrupting the bridge balance and generating a differential voltage signal proportional to the hydrogen concentration. The microcontroller 23 continuously samples and processes this signal, calculating in real time the change in thermal conductivity reflecting the change in hydrogen concentration.

[0082] When the change in thermal conductivity indicates that the hydrogen concentration in the environment has reached or exceeded a predetermined concentration threshold, the alarm module 6 is controlled to issue an alarm.

[0083] The microcontroller 23 compares the real-time calculated change in thermal conductivity with a preset safe concentration threshold. This threshold corresponds to a safe percentage of the lower explosive limit of hydrogen. Once the detected signal reaches or exceeds this preset threshold, the microcontroller 23 immediately determines that a dangerous leak has occurred and then controls the alarm module 6 to issue an alarm.

[0084] The detection method disclosed in this application utilizes the physical difference principle of the miniature thermal conductivity detector 3 and the stable sample injection capability of the Knudsen pump 4 to achieve instant safety alarms without measurement through reliable threshold comparison. The entire method is efficient, reliable, and has controllable power consumption, perfectly meeting the requirements of wearable devices for real-time performance, accuracy, and long battery life, providing continuous, close-fitting, and reliable safety protection for staff.

[0085] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A wristband-type hydrogen detection device, characterized in that, include: Bracelet casing; A flexible circuit board is disposed inside the wristband housing, and a rigid patch area is provided on the flexible circuit board; A miniature thermal conductivity detector is disposed on the rigid patch area of ​​the flexible circuit board and electrically connected to the flexible circuit board for detecting hydrogen concentration; A Knudsen pump is disposed on the rigid patch area of ​​the flexible circuit board and electrically connected to the flexible circuit board, for actively pumping ambient gas to the miniature thermal conductivity detector. A connecting component, made of flexible thermal insulation material, is connected between the outlet of the Knudsen pump and the inlet of the miniature thermal conductivity detector to connect the air path and provide thermal insulation. An alarm module is mounted on and electrically connected to the flexible circuit board, and is used to issue an alarm when the hydrogen concentration reaches a threshold.

2. The wristband-type hydrogen detection device as described in claim 1, characterized in that: The Knudsen pump includes: The pump body has an air inlet and an air outlet; A heat dissipation component is fitted onto the side of the pump body corresponding to the air inlet; A pumping functional layer is disposed within the pump body and located on the gas flow channel between the air inlet and the air outlet; A heating element is disposed within the pump body and electrically connected to the flexible circuit board; The heating element is used to heat the pumping functional layer and, together with the heat sink, forms a temperature gradient on both sides of the pumping functional layer to drive the gas from the inlet to the outlet.

3. The wristband-type hydrogen detection device as described in claim 2, characterized in that: The pump body further includes a first glass chip, a second glass chip, and a third glass chip stacked together. Microchannels are etched inside the first glass chip, the second glass chip, and the third glass chip. The microchannels together form a gas flow channel from the air inlet to the air outlet. The pumping functional layer is bonded between the first glass chip and the second glass chip. The heating element is fixedly disposed between the second glass chip and the third glass chip.

4. The wristband-type hydrogen detection device as described in claim 2 or 3, characterized in that: The Knudsen pump also includes an air intake pipe, one end of which passes through a heat sink and is connected to an air inlet on the pump body, and the other end extends to the outside of the wristband housing. A primary coarse filter and a secondary fine filter are sequentially arranged inside the air intake pipe along the air intake direction.

5. The wristband-type hydrogen detection device as described in claim 3, characterized in that: The pumping functional layer is an integral porous silicon structure with nanoscale through-holes, which is bonded between the first glass chip and the second glass chip, and the nanoscale through-holes constitute part of the gas flow channel.

6. The wristband-type hydrogen detection device as described in claim 1, characterized in that: The connecting component includes: The connecting body is made of flexible thermal insulation material; A first flow channel and a second flow channel are formed within the connecting body. The inlet of the first flow channel is used to connect to the outlet of the Knudsen pump, and the outlet of the second flow channel is used to connect to the inlet of the miniature thermal conductivity detector; and A flexible microtube is embedded within the connecting body and connects the first flow channel to the second flow channel.

7. The wristband-type hydrogen detection device as described in claim 6, characterized in that: The miniature thermal conductivity detector includes: The encapsulation housing has an air inlet and an air outlet, and the air inlet of the encapsulation housing is in fluid communication with the air outlet of the Knudsen pump through the connecting member; A reference cell, which is sealed within the encapsulation housing and filled with a reference gas; The detection pool, which is disposed within the encapsulation housing and communicates with the second flow channel outlet of the connecting member; and Two thermistors are respectively disposed in the reference cell and the detection cell; wherein the two thermistors are used to connect to a Wheatstone bridge circuit to detect changes in the thermal conductivity of the gas in the detection cell.

8. The wristband-type hydrogen detection device as described in claim 7, characterized in that: The reference gas filled in the reference pool is pure air.

9. The wristband-type hydrogen detection device as described in claim 1, characterized in that: The flexible circuit board is a structure combining a flexible PCB substrate and a partially rigid patch. It also integrates a microcontroller and a signal conditioning module. The microcontroller and signal conditioning module are used to process the signal of the miniature thermal conductivity detector and control the alarm module and the Knudsen pump. The alarm module includes a micro-flat vibration motor, a micro-surface buzzer, and a surface-mount LED. The micro-surface buzzer and the micro-flat vibration motor are disposed on the rigid surface-mount, and the surface-mount LED is disposed in the flexible area of ​​the flexible PCB substrate.

10. A detection method using the wristband-type hydrogen detection device as described in claim 7 or 8, characterized in that, Includes the following steps: The Knudsen pump and the miniature thermal conductivity detector are activated, and the ambient gas is pumped into the detection pool through the Knudsen pump; The miniature thermal conductivity detector is initialized and calibrated to eliminate the Wheatstone bridge bias voltage caused by the initial composition difference between the reference gas and the ambient gas. The ambient gas is continuously pumped into the detection cell through the Knudsen pump, and the change in thermal conductivity of the gas in the detection cell is detected by the miniature thermal conductivity detector. When the change in thermal conductivity indicates that the hydrogen concentration in the environment has reached or exceeded a predetermined concentration threshold, the alarm module is controlled to issue an alarm.

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