Gas leakage detection device

Abstract

The utility model provides a gas leakage detection device, and belongs to the technical field of gas leakage detection. The gas leakage detection device comprises a power supply module, a thermal conductivity chip module, a divider resistor module, an operational amplifier and a micro-control unit. In the application, the differential voltage signal output by the thermal conductivity chip module is subjected to voltage division processing through the divider resistance module and then is input into the operational amplifier, so that the differential voltage signal can be matched with the voltage processing range of the subsequent operational amplifier, and meanwhile, a tiny leakage signal can be located in a high-sensitivity interval of the operational amplifier after being subjected to voltage division; and by combining a subsequent operational amplifier, the capability of distinguishing weak leakage signals can be improved, and the sensitivity of gas leakage detection can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of gas leakage detection, and in particular to a gas leakage detection device. Background Art

[0002] There are many methods for detecting gas leaks, including one that leverages the effect of gas concentration on thermal conductivity. For example, patent application publication number CN116009450A discloses a method for determining changes in gas concentration by detecting changes in the gas's ability to transfer heat. In this method, a differential signal generated and output by a sensing element, in response to changes in gas concentration, is directly input into a microcontroller chip within the data processing circuit, where it performs analog-to-digital conversion and signal amplification. However, existing technologies may result in the differential signal (actually a voltage signal) output by the sensing element not matching the voltage range capable of processing the subsequent data processing circuit. Utility Model Content

[0003] The main purpose of the embodiments of the present application is to provide a gas leak detection device, which aims to set a voltage divider resistor module between the thermal conductivity chip module and the operational amplifier to perform voltage division processing on the differential signal output by the thermal conductivity chip module so that it can match the voltage processing range of the subsequent operational amplifier.

[0004] To achieve the above objectives, the present application provides a gas leakage detection device, comprising: a power supply module, a thermal conductivity chip module, a voltage divider resistor module, an operational amplifier, and a microcontroller unit;

[0005] The voltage output end of the power supply module is connected to the thermal conductivity chip module to supply power to the thermal conductivity chip module;

[0006] The negative output terminal of the thermal conductivity chip module is connected to the input terminal of the voltage divider resistor module, and the positive output terminal of the thermal conductivity chip module is connected to the positive input terminal of the operational amplifier;

[0007] The first output end of the voltage-dividing resistor module is connected to the negative input end of the operational amplifier, and the second output end of the voltage-dividing resistor module is connected to the analog power input end of the operational amplifier;

[0008] The output end of the operational amplifier is connected to the micro control unit.

[0009] In one embodiment of the present application, the power module includes a power control chip and a first capacitor;

[0010] The first pin of the power control chip serves as a voltage input terminal for receiving a power voltage provided by an external device;

[0011] The second pin of the power control chip is grounded, and the third pin of the power control chip serves as an enable control terminal for receiving the output voltage after LDO voltage stabilization;

[0012] The fifth pin of the power control chip is connected to the thermal conductivity chip module as the voltage output terminal. The fifth pin of the power control chip is also connected to the first end of the first capacitor, and the second end of the first capacitor is grounded.

[0013] In one embodiment of the present application, the thermally conductive chip module includes a single thermally conductive chip and a first resistor arranged in series;

[0014] The single thermal conductive chip includes a first heat source pin, a second heat source pin, a positive thermal resistor pin and a negative thermal resistor pin, and a thermopile is connected between the positive thermal resistor pin and the negative thermal resistor pin;

[0015] The positive thermal resistor pin serves as the positive output terminal of the thermal conductivity chip module and is connected to the positive input terminal of the operational amplifier, and the negative thermal resistor pin serves as the negative output terminal of the thermal conductivity chip module and is connected to the input terminal of the voltage divider resistor module;

[0016] The first heat source pin is grounded, the second heat source pin is connected to a first end of the first resistor, and the second end of the first resistor is connected to a voltage output end of the power module.

[0017] In one embodiment of the present application, the first resistor is detachably connected between the second heat source pin and the voltage output end of the power module, and / or the first resistor is an adjustable resistor.

[0018] In one embodiment of the present application, the voltage-dividing resistor module includes a second resistor, a third resistor, a fourth resistor and a second capacitor;

[0019] The first end of the second resistor is connected to the analog power input end of the operational amplifier as the second output end of the voltage divider resistor module;

[0020] The second end of the second resistor is connected to the negative input end of the operational amplifier as the first output end of the voltage divider resistor module;

[0021] The negative output terminal of the thermal conductivity chip module is connected to the first end of the third resistor, the second end of the third resistor is connected to the negative input terminal of the operational amplifier, and the second end of the third resistor is also connected to the second end of the second resistor;

[0022] The negative output terminal of the thermal conductivity chip module is also connected to the first end of the fourth resistor, and the second end of the fourth resistor is grounded;

[0023] The second capacitor is connected between the positive input terminal and the negative input terminal of the operational amplifier.

[0024] In one embodiment of the present application, the voltage output terminal of the power supply module can intermittently supply power to the thermal conductive chip module.

[0025] In one embodiment of the present application, the gas leakage detection device further includes an air pressure detection device, and the air pressure detection device is electrically connected to the micro control unit.

[0026] In one embodiment of the present application, the gas leakage detection device further includes a temperature and humidity detection device, and the temperature and humidity detection device is electrically connected to the micro control unit.

[0027] In one embodiment of the present application, the gas leakage detection device further includes a heating module, the heating module includes an electric heating element and an electric heating drive circuit, and the electric heating drive circuit is electrically connected to the micro control unit.

[0028] In one embodiment of the present application, the electrothermal driving circuit includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, and a first transistor;

[0029] The fifth resistor, the sixth resistor, the seventh resistor and the eighth resistor are connected in parallel between the electric heating element and the drain of the first transistor;

[0030] The source of the first transistor is grounded, and the source of the first transistor is also connected to the first end of the ninth resistor. The second end of the ninth resistor is connected to the gate of the first transistor, and the gate of the first transistor is also connected to the micro control unit.

[0031] In the technical solution provided in the embodiments of the present application, a gas leak detection device includes a power supply module, a thermal conductivity chip module, a voltage divider resistor module, an operational amplifier, and a microcontroller unit. The thermal conductivity chip module is capable of sensing the target gas concentration in the measured environment. When the target gas concentration in the measured environment changes, the thermal conductivity chip module generates an electrical signal difference and outputs a differential voltage signal. The output differential voltage signal passes through the voltage divider resistor module and is then input into the operational amplifier for signal amplification to obtain the original signal value. The original signal value is then input into the microcontroller unit for computational processing to obtain a detection result indicating whether a gas leak has occurred. In the present application, the differential voltage signal output by the thermal conductivity chip module is divided by the voltage divider resistor module before being input into the operational amplifier, enabling it to match the voltage processing range of the subsequent operational amplifier. Furthermore, after voltage division, the tiny leakage signal can be placed within the high sensitivity range of the operational amplifier. Combined with the subsequent operational amplifier, this can enhance the resolution of weak leakage signals and improve the sensitivity of gas leak detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a block diagram of the gas leakage detection device provided in Example 1 of the present application.

[0033] Figure 2 This is a circuit diagram of a power module provided in one embodiment of the present application.

[0034] Figure 3 4 is a circuit diagram of a thermal conductive chip module provided in one embodiment of the present application.

[0035] Figure 4 4 is a circuit diagram of a voltage divider resistor module provided in one embodiment of the present application.

[0036] Figure 5 is a circuit diagram of an operational amplifier provided in one embodiment of the present application.

[0037] Figure 6 This is a circuit diagram of a micro control unit provided in one embodiment of the present application.

[0038] Figure 7 This is a block diagram of a gas leakage detection device provided in Example 2 of the present application.

[0039] Figure 8 1 is a circuit diagram of an air pressure detection device provided in one embodiment of the present application.

[0040] Figure 9 This is a block diagram of the gas leakage detection device provided in Example 3 of the present application.

[0041] Figure 10 This is a circuit diagram of a temperature and humidity detection device provided in one embodiment of the present application.

[0042] Figure 11 This is a block diagram of a gas leakage detection device provided in Example 4 of the present application.

[0043] Figure 12 4 is a circuit diagram of an electrothermal drive circuit provided in one embodiment of the present application.

[0044] Figure 13 Schematic diagram of the circuit connection of the thermal conductivity chip module, the voltage divider resistor module and the operational amplifier in one embodiment of the present application.

[0045] Reference numerals:

[0046] 100. Power supply module, 200. Thermal conductivity chip module, 300. Voltage divider resistor module, 400. Operational amplifier, 500. Microcontroller unit, 600. Air pressure detection device, 700. Temperature and humidity detection device, 800. Heating module, 810. Electric heating drive circuit. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0048] It should be noted that although the device schematics illustrate functional module divisions and the flowcharts illustrate logical sequences, in certain circumstances, the steps shown or described may be performed in a sequence that differs from the module divisions in the device or the sequence in the flowcharts. The terms "first," "second," and so on, in the specification, claims, and drawings, are used to distinguish similar items and are not necessarily used to describe a specific sequence or precedence.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein are for the purpose of describing the embodiments of this application only and are not intended to limit this application.

[0050] In recent years, various new refrigerants have become extremely popular. New refrigerants are low-priced and environmentally friendly, and have good application prospects for environmental protection and energy conservation.

[0051] In practical applications, new refrigerants can form explosive mixtures when mixed with air, posing a risk of combustion and explosion when exposed to heat or open flames. Reducing the filling volume, isolating ignition sources, preventing leaks, and improving safety measures after leaks can reduce the risk of explosion and damage. Increasing gas leak detection is one of the safety measures.

[0052] There are many methods for gas leak detection, including one that leverages the effect of gas concentration on thermal conductivity. Existing methods that leverage this effect suffer from a mismatch between the differential signal (actually a voltage signal) output by the sensing element and the voltage range capable of subsequent data processing circuitry. Furthermore, existing technologies may be unable to detect weak leakage signals and suffer from insufficient detection sensitivity.

[0053] Based on this, the present invention proposes a gas leak detection device that incorporates a voltage-divider resistor module between a thermal conductivity chip module and an operational amplifier. This resistor divides the differential signal output by the thermal conductivity chip module to match the voltage processing range of the subsequent operational amplifier. Furthermore, this device improves the ability to resolve weak leakage signals and enhances detection sensitivity. Example 1

[0054] Figure 1This is a block diagram of the gas leakage detection device provided in Example 1 of this application. Figure 1 and Figure 13 As shown, the gas leakage detection device includes a power supply module 100 , a thermal conductivity chip module 200 , a voltage divider resistor module 300 , an operational amplifier 400 and a micro control unit 500 .

[0055] The voltage output terminal of the power module 100 is connected to the thermal conductivity chip module 200 to provide independent power to the thermal conductivity chip module 200. The operational amplifier 400 and the microcontroller unit 500 can be powered by a power supply voltage provided by an external device. The external device can be an integrated object of the gas leak detection device. If the gas leak detection device is integrated into an air conditioner, the external device is the air conditioner.

[0056] In this embodiment of the present application, the thermal conductivity chip module 200 is independently powered by the power module 100, effectively suppressing power supply coupling interference and meeting the differentiated voltage requirements for powering the thermal conductivity chip module 200, the operational amplifier 400, and the microcontroller unit 500. Specifically, the thermal conductivity chip module 200 is prone to generating high-frequency ripple during operation. Independent power supply prevents this noise from coupling from the common power supply to the operational amplifier 400 and the microcontroller unit 500, thereby reducing analog signal acquisition errors. During gas leak detection, the thermal conductivity chip module 200 may draw sudden high currents. Independent power supply prevents load fluctuations from causing voltage drops in the microcontroller unit 500 and triggering reset failures.

[0057] The negative output terminal of the thermal conductivity chip module 200 is connected to the input terminal of the voltage divider resistor module 300, and the positive output terminal of the thermal conductivity chip module 200 is connected to the positive input terminal of the operational amplifier 400. The first output terminal of the voltage divider resistor module 300 is connected to the negative input terminal of the operational amplifier 400, and the second output terminal of the voltage divider resistor module 300 is connected to the analog power input terminal of the operational amplifier 400. The output terminal of the operational amplifier 400 is connected to the microcontroller unit 500.

[0058] In the embodiment of the present application, the thermal conductivity chip module 200 can sense the concentration of the target gas in the measured environment. When the target gas concentration in the measured environment changes, the thermal conductivity chip module 200 generates an electrical signal difference and outputs a differential voltage signal. The output differential voltage signal is divided by the voltage divider resistor module 300 and input into the operational amplifier 400, which amplifies the signal to obtain the original signal value. The original signal value is then input into the microcontroller unit 500 for processing to obtain a gas leak detection result. Based on the principle that gas concentration affects thermal conductivity, this application determines the change in gas concentration by detecting changes in the gas's heat transfer ability. This can significantly shorten the warm-up process and detection time, and has lower power consumption. Unlike electrochemical sensors that suffer from material loss, the sensor of this embodiment has an extremely long service life. Furthermore, the differential voltage signal output by the thermal conductivity chip module 200 is divided by the voltage divider resistor module 300 before being input into the operational amplifier 400, ensuring that it matches the voltage processing range of the subsequent operational amplifier. By setting the voltage divider resistor module 300, the tiny leakage signal can be placed in the high sensitivity range of the operational amplifier 400 after being divided by the voltage divider resistor module 300, thereby improving the operational amplifier 400's ability to resolve weak leakage signals and enhancing detection sensitivity.

[0059] Figure 2 : is a circuit diagram of a power module provided in one embodiment of the present application. Figure 2As shown, the power module 100 includes a power control chip U1 and a first capacitor C1. The first pin (i.e., IN pin) of the power control chip U1 serves as a voltage input terminal for receiving a power voltage provided by an external device. The second pin (i.e., GND pin) of the power control chip U1 is grounded. The third pin (i.e., EN / NC pin) of the power control chip U1 serves as an enable control terminal for receiving the regulated output voltage VLDO_EN of an LDO (linear regulator). This regulated output voltage VLDO_EN controls whether the power control chip U1 is active, enabling intermittent power supply to the thermal conductivity chip module 200. For example, when the regulated output voltage VLDO_EN connected to the third pin of the power control chip U1 is high, the power control chip U1 is active, thus providing power to the thermal conductivity chip module 200. However, when the regulated output voltage VLDO_EN connected to the third pin of the power control chip U1 is low, the power control chip U1 is inactive and cannot provide power to the thermal conductivity chip module 200. The fifth pin (i.e., the OUT pin) of the power control chip U1 serves as a voltage output terminal and is connected to the thermal conductivity chip module 200 to supply power to the thermal conductivity chip module 200. The fifth pin of the power control chip U1 is also connected to the first terminal of a first capacitor C1, the second terminal of which is grounded. The first capacitor C1 can directly bypass high-frequency interference from the voltage output terminal to ground, preventing noise from being transmitted to subsequent circuits (i.e., the thermal conductivity chip module 200).

[0060] In this embodiment of the present application, an automotive-grade LDO device is used to convert an unstable input power source (such as a vehicle battery) into a stable, pure output voltage, which is then connected to the power module 100. This converts the fluctuating input into a precise, reliable regulated output, which is then connected to a load circuit such as the thermal conductivity chip module 200. This reduces temperature drift and prevents power supply ripple from contaminating the microvolt-level differential signal output by the thermal conductivity chip module 200.

[0061] Figure 3 : is a circuit diagram of a thermal conductive chip module provided by an embodiment of the present application. Figure 3As shown, the thermal conductivity chip module 200 includes a single thermal conductivity chip U2 and a first resistor R1 arranged in series. The single thermal conductivity chip U2 includes a first heat source pin HEATER1, a second heat source pin HEATER2, a positive thermal resistor pin TH+, and a negative thermal resistor pin TH-. A thermopile is connected between the positive thermal resistor pin TH+ and the negative thermal resistor pin TH-. The positive thermal resistor pin TH+ serves as the positive output terminal of the thermal conductivity chip module 200 and is connected to the positive input terminal (i.e., the SIP pin) of the operational amplifier 400. The negative thermal resistor pin TH- serves as the negative output terminal of the thermal conductivity chip module 200 and is connected to the input terminal of the voltage divider resistor module 300. The first heat source pin HEATER1 is grounded, the second heat source pin HEATER2 is connected to the first terminal of the first resistor R1, and the second terminal of the first resistor R1 is connected to the voltage output terminal of the power module 100, i.e., to the fifth pin of the power control chip U1.

[0062] In an embodiment of the present application, when a specified voltage is applied between the first heat source pin HEATER1 and the second heat source pin HEATER2, a stable heat source is generated between the first heat source pin HEATER1 and the second heat source pin HEATER2, and heat is transferred to the surface of the thermopile through the gas molecules in the measured environment. When the target gas concentration in the measured environment changes, an electrical signal difference can be generated between the positive thermistor pin TH+ and the negative thermistor pin TH-, and the differential signal is detected; the target gas concentration is proportional to the heat carried by the gas molecules in the measured environment.

[0063] The size of the specified voltage can be set according to the actual application scenario. Different application scenarios correspond to different specified voltages. Therefore, gas leaks in different application scenarios can be detected, reducing the impact of environmental changes on the accuracy of detection results.

[0064] In the embodiment of the present application, the first resistor R1 is a voltage dividing resistor connected to the fifth pin of the power control chip U1 and can perform voltage dividing processing on the power voltage provided by the power module 100 .

[0065] Specifically, the first resistor R1 can be detachably connected between the second heat source pin HEATER2 of the single thermal conductivity chip U2 and the fifth pin of the power control chip U1, thereby meeting the voltage requirements of different thermal conductivity chip modules 200. Alternatively, the first resistor R1 can be an adjustable resistor, similarly meeting the voltage requirements of different thermal conductivity chip modules 200.

[0066] In the embodiment of the present application, the core principle of the thermal conductivity chip module 200 for detecting gas leaks is based on the physical difference in thermal conductivity of different gases. Leak identification is achieved by measuring the change in thermal conductivity characteristics caused by changes in gas composition. Specifically, different gas molecular structures lead to different thermal conductivity capabilities. The thermal conductivity of gases (such as R134a and R410A) is significantly lower than that of air. When gas leaks, the thermal conductivity of the local gas mixture will be significantly reduced due to the increase in gas concentration. A single thermal conductivity chip U2 can usually adopt a Wheatstone bridge design, that is, two thermistors form a bridge arm, one exposed to the ambient gas (detection end) and the other sealed in a reference gas (compensation end). When gas leaks, the heat dissipation efficiency of the detection end decreases, causing the temperature to rise, thereby generating a change in resistance value, and ultimately causing the bridge to be unbalanced, outputting a differential voltage signal.

[0067] Figure 4 : is a circuit diagram of a voltage divider resistor module provided in one embodiment of the present application. Figure 4 As shown, the voltage divider resistor module 300 includes a second resistor R2, a third resistor R3, a fourth resistor R4, and a second capacitor C2. The first end of the second resistor R2, serving as the second output of the voltage divider resistor module 300, is connected to the analog power input (i.e., the SVDD pin) of the operational amplifier 400. The second end of the second resistor R2, serving as the first output of the voltage divider resistor module 300, is connected to the negative input (i.e., the SIN pin) of the operational amplifier 400. The negative output (i.e., the negative thermal resistor pin TH-) of the thermal conductivity chip module 200 is connected to the first end of the third resistor R3. The second end of the third resistor R3 is connected to the negative input (i.e., the SIN pin) of the operational amplifier 400. The second end of the third resistor R3 is also connected to the second end of the second resistor R2 and then connected to the negative input (i.e., the SIN pin) of the operational amplifier 400. The negative output (i.e., the negative thermal resistor pin TH-) of the thermal conductivity chip module 200 is also connected to the first end of the fourth resistor R4. The second end of the fourth resistor R4 is grounded. Optionally, a common mode voltage VCM is connected between the third resistor R3 and the fourth resistor R4. The second capacitor C2 is connected between the positive input terminal (ie, the SIP pin) and the negative input terminal (ie, the SIN pin) of the operational amplifier 400.

[0068] In this embodiment of the present application, the positive signal output from the positive output terminal of the thermal conductivity chip module 200 (i.e., the positive thermal resistor pin TH+) is directly connected to the non-inverting terminal of the operational amplifier 400. The negative signal output from the negative output terminal of the thermal conductivity chip module 200 (i.e., the negative thermal resistor pin TH-) is divided by a third resistor R3 and then input to the inverting terminal of the operational amplifier 400, forming a standard differential amplification structure. A second capacitor C2 is connected across the positive and negative input terminals of the operational amplifier 400 to form a differential low-pass filter, which suppresses high-frequency noise. The negative signal output from the negative output terminal of the thermal conductivity chip module 200 (i.e., the negative thermal resistor pin TH-) is divided by a third resistor R3 and a second resistor R2 and then coupled to the SVDD pin of the operational amplifier 400. This achieves common-mode tracking and noise cancellation. Specifically, the analog power supply pin can compensate for input common-mode fluctuations, and the analog power supply signal injection can suppress common-mode interference. Especially in weak signal scenarios, this noise elimination and interference suppression can improve the resolution of weak leakage signals and enhance the sensitivity of gas leak detection.

[0069] In this embodiment of the present application, when a gas leak occurs, the thermal conductivity chip module 200 may output a high-voltage differential signal (e.g., ±5V), exceeding the input voltage range of the operational amplifier 400 (typically ±3.3V). The voltage divider resistor module 300 proportionally attenuates the signal to match the voltage handling range of the operational amplifier 400, preventing input saturation or damage to the operational amplifier 400. Furthermore, the thermal conductivity chip module 200 has a high output impedance, and direct connection to the high input impedance of the operational amplifier 400 can easily cause signal reflections. The voltage divider resistor module 300 acts as a buffer layer, reducing signal distortion caused by sensor loading. To address the wide dynamic range of both minute leakage signals (mV level) and large leakage signals (V level), the voltage divider resistor module 300 allows for adjustable amplification. For example, in the high-voltage range, enabling voltage division prevents overloading of the operational amplifier 400. In the low-voltage range, bypassing the voltage divider resistor allows for direct amplification of weak signals, improving resolution and detection sensitivity.

[0070] Figure 5 This is a circuit diagram of an operational amplifier provided in one embodiment of the present application. In some embodiments, operational amplifier 400 is an instrumentation-grade programmable operational amplifier. This instrumentation-grade programmable operational amplifier allows real-time gain adjustment via a digital interface without the need to replace external resistors, achieving a gain error of less than 0.01%, thus avoiding the accuracy loss associated with traditional op amps due to resistor temperature drift.

[0071] In some embodiments, the voltage output terminal of the power module 100 can intermittently power the thermal conductivity chip module 200. The thermal conductivity chip module 200 only requires high current heating during the detection cycle. Intermittent power supply allows it to enter a microampere-level sleep state when idle, thereby reducing power consumption and extending device life. The power module 100 can be linked with the microcontroller unit 500 to achieve on-demand power supply.

[0072] Figure 6 This is a circuit diagram of a microcontroller unit 500 provided in one embodiment of the present application. In some embodiments, the microcontroller unit 500 is connected to an operational amplifier 400 to receive the original signal value obtained through signal amplification processing by the operational amplifier 400. The microcontroller unit 500 performs computations on the detected original signal value to ultimately determine a leakage determination result. The microcontroller unit 500 performs computations on the detected original signal value to ultimately determine a leakage determination result, which is conventional technology and will not be further described here. Example 2

[0073] Reference Figure 7-Figure 8 , Figure 7 is a block diagram of a gas leakage detection device provided in Example 2 of the present application, Figure 8 : is a circuit diagram of an air pressure detection device provided by an embodiment of the present application. Figure 7 As shown, the gas leak detection device includes, in addition to a power module 100, a thermal conductivity chip module 200, a voltage divider resistor module 300, an operational amplifier 400, and a microcontroller unit 500, an air pressure detection device 600. The air pressure detection device 600 is electrically connected to the microcontroller unit 500 and can also be electrically connected to an external device, that is, the external device can provide power to the air pressure detection device 600.

[0074] In some embodiments, reference Figure 8 , the air pressure detection device 600 can be a barometer. The air pressure detection device 600 is used to measure the air pressure value in the measured environment and feed back the measured air pressure value to the micro control unit 500. Taking into account that the thermal conductivity of the gas will be different at different air pressures, by electrically connecting the air pressure detection device 600 to the micro control unit 500, the micro control unit 500 can obtain the air pressure value in the measured environment, so that air pressure compensation can be performed according to the air pressure value in the measured environment, which can significantly improve the accuracy of leak detection. Specifically, the thermal conductivity of the gas shows a nonlinear relationship with the change of air pressure. Especially in the low air pressure range (<100kPa), the rate of decrease of thermal conductivity is accelerated. When air pressure compensation is not performed, the drop in air pressure may cause the output signal of the thermal conductivity chip module 200 to deviate, resulting in a false alarm.

[0075] It is understood that the specific pressure compensation calculation can refer to the Chinese patent with publication number CN109696412A and invention name "Infrared gas sensor and pressure compensation method based on AGNES optimized BP neural network". Example 3

[0076] Reference Figure 9-10 , Figure 9 is a block diagram of a gas leakage detection device provided in Example 3 of the present application, Figure 10 This is a circuit diagram of a temperature and humidity detection device provided by an embodiment of the present application. Figure 9 As shown, the gas leakage detection device includes, in addition to a power module 100, a thermal conductivity chip module 200, a voltage divider resistor module 300, an operational amplifier 400, a microcontroller unit 500, and an air pressure detection device 600, a temperature and humidity detection device 700. The temperature and humidity detection device 700 is electrically connected to the microcontroller unit 500 and can also be electrically connected to an external device, that is, the external device can provide power to the temperature and humidity detection device 700.

[0077] In some embodiments, reference Figure 10 , the temperature and humidity detection device 700 may be a thermometer and hygrometer. The temperature and humidity detection device 700 is used to measure the humidity in the measured environment and feed back the measured humidity to the microcontroller unit 500. Taking into account that the thermal conductivity of the gas will be different at different humidity, by electrically connecting the temperature and humidity detection device 700 to the microcontroller unit 500, the microcontroller unit 500 can obtain the humidity in the measured environment, so that humidity compensation can be performed according to the humidity in the measured environment, which can significantly improve the accuracy of leakage detection. Specifically, the thermal conductivity of dry air is about 0.026W / (m·K), while the thermal conductivity of water vapor is 0.59W / (m·K). An increase in humidity will cause the thermal conductivity of the mixed gas to increase. When humidity compensation is not performed, an increase in humidity may cause the output signal of the thermal conductivity chip module 200 to deviate, resulting in a misjudgment of leakage detection.

[0078] It is understood that for specific temperature compensation and humidity compensation calculations, reference may be made to the Chinese patent publication number CN119001034A, entitled “A MEMS Hydrogen Sensor and Its Temperature Compensation Method”. Example 4

[0079] Reference Figure 11-12 , Figure 11 is a block diagram of a gas leakage detection device provided in Example 4 of the present application, Figure 12 : is a circuit diagram of an electrothermal drive circuit provided by an embodiment of the present application. Figure 11As shown, the gas leak detection device includes, in addition to a power module 100, a thermal conductivity chip module 200, a voltage divider resistor module 300, an operational amplifier 400, a microcontroller unit 500, an air pressure detection device 600, and a temperature and humidity detection device 700, a heating module 800. The heating module 800 includes an electric heating element (not shown) and an electric heating drive circuit 810, which is electrically connected to the microcontroller unit 500.

[0080] In some embodiments, reference Figure 12 The electrothermal drive circuit 810 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a first transistor Q1. The fifth resistor R5, the sixth resistor R6, the seventh resistor R7, and the eighth resistor R8 are connected in parallel between the electrothermal element HTR and the drain of the first transistor Q1. The source of the first transistor Q1 is grounded, and the source of the first transistor Q1 is also connected to the first end of the ninth resistor R9. The second end of the ninth resistor R9 is connected to the gate of the first transistor Q1. The gate of the first transistor Q1 is also connected to the micro-control unit 500.

[0081] In the embodiment of the present application, considering that the thermal conductivity chip module 200 needs to operate in a non-condensing environment, a heating module 800 is designed, and the electrothermal drive circuit 810 in the heating module 800 is electrically connected to the microcontroller unit 500. This prevents water vapor from condensing into water droplets in low-temperature environments, which could affect the operation of the thermal conductivity chip module 200 and thus affect gas leak detection. Specifically, when the microcontroller unit 500 detects that the measured environment may enter a condensing state, it can send a control signal to the gate of the first transistor Q1 to control the electrothermal drive circuit 810 to drive the electrothermal element HTR to operate, thereby heating the measured environment and ensuring that the thermal conductivity chip module 200 operates in a non-condensing environment.

[0082] It can be understood that the judgment of the specific condensation state of the measured environment can refer to the record in paragraph 0025 of the Chinese patent specification with publication number CN119001034A and invention name "A MEMS hydrogen sensor and its temperature compensation method".

[0083] The embodiments described in the embodiments of this application are intended to more clearly illustrate the technical solutions of the embodiments of this application and do not constitute a limitation on the technical solutions provided by the embodiments of this application. Those skilled in the art will appreciate that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0084] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer steps than shown in the figures, or a combination of certain steps, or different steps.

[0085] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, i.e., they may be located in one place or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of this embodiment.

[0086] Those skilled in the art will appreciate that all or some of the steps in the methods, systems, and functional modules / units in the devices disclosed above may be implemented as software, firmware, hardware, or appropriate combinations thereof.

[0087] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0088] It should be understood that in this application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0089] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the above-mentioned units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0090] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0091] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and essence of the present invention should be within the scope of the present invention.

Claims

1. A gas leak detection device, characterized in that: include: Power supply module, thermal conductivity chip module, voltage divider resistor module, operational amplifier and micro control unit; The voltage output end of the power supply module is connected to the thermal conductivity chip module to supply power to the thermal conductivity chip module; The negative output terminal of the thermal conductivity chip module is connected to the input terminal of the voltage divider resistor module, and the positive output terminal of the thermal conductivity chip module is connected to the positive input terminal of the operational amplifier; The first output end of the voltage-dividing resistor module is connected to the negative input end of the operational amplifier, and the second output end of the voltage-dividing resistor module is connected to the analog power input end of the operational amplifier; The output end of the operational amplifier is connected to the micro control unit.

2. The gas leakage detection device according to claim 1, characterized in that: The power module includes a power control chip and a first capacitor; The first pin of the power control chip serves as a voltage input terminal for receiving a power voltage provided by an external device; The second pin of the power control chip is grounded, and the third pin of the power control chip serves as an enable control terminal; The fifth pin of the power control chip is connected to the thermal conductivity chip module as the voltage output terminal. The fifth pin of the power control chip is also connected to the first end of the first capacitor, and the second end of the first capacitor is grounded.

3. The gas leakage detection device according to claim 1, wherein: The thermal conductivity chip module includes a single thermal conductivity chip and a first resistor arranged in series; The single thermal conductive chip includes a first heat source pin, a second heat source pin, a positive thermal resistor pin and a negative thermal resistor pin, and a thermopile is connected between the positive thermal resistor pin and the negative thermal resistor pin; The positive thermal resistor pin serves as the positive output terminal of the thermal conductivity chip module and is connected to the positive input terminal of the operational amplifier, and the negative thermal resistor pin serves as the negative output terminal of the thermal conductivity chip module and is connected to the input terminal of the voltage divider resistor module; The first heat source pin is grounded, the second heat source pin is connected to a first end of the first resistor, and the second end of the first resistor is connected to a voltage output end of the power module.

4. The gas leakage detection device according to claim 3, characterized in that: The first resistor is detachably connected between the second heat source pin and the voltage output terminal of the power module, and / or the first resistor is an adjustable resistor.

5. The gas leakage detection device according to claim 1, wherein: The voltage-dividing resistor module includes a second resistor, a third resistor, a fourth resistor and a second capacitor; The first end of the second resistor is connected to the analog power input end of the operational amplifier as the second output end of the voltage divider resistor module; The second end of the second resistor is connected to the negative input end of the operational amplifier as the first output end of the voltage divider resistor module; The negative output terminal of the thermal conductivity chip module is connected to the first end of the third resistor, the second end of the third resistor is connected to the negative input terminal of the operational amplifier, and the second end of the third resistor is also connected to the second end of the second resistor; The negative output terminal of the thermal conductivity chip module is also connected to the first end of the fourth resistor, and the second end of the fourth resistor is grounded; The second capacitor is connected between the positive input terminal and the negative input terminal of the operational amplifier.

6. The gas leakage detection device according to claim 1, characterized in that: The voltage output end of the power supply module can intermittently supply power to the thermal conductive chip module.

7. The gas leakage detection device according to claim 1, characterized in that: The gas leakage detection device further includes an air pressure detection device, and the air pressure detection device is electrically connected to the micro control unit.

8. The gas leakage detection device according to claim 1, wherein: The gas leakage detection device further includes a temperature and humidity detection device, which is electrically connected to the micro control unit.

9. The gas leakage detection device according to any one of claims 1 to 8, characterized in that: The gas leakage detection device further includes a heating module, which includes an electric heating element and an electric heating drive circuit, and the electric heating drive circuit is electrically connected to the micro control unit.

10. The gas leakage detection device according to claim 9, characterized in that: The electrothermal driving circuit includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a first transistor; The fifth resistor, the sixth resistor, the seventh resistor and the eighth resistor are connected in parallel between the electric heating element and the drain of the first transistor; The source of the first transistor is grounded, and the source of the first transistor is also connected to the first end of the ninth resistor. The second end of the ninth resistor is connected to the gate of the first transistor, and the gate of the first transistor is also connected to the micro control unit.

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