Reference probe and gas detection device

Abstract

A reference probe for gas detection. The reference probe is provided with a first cavity, and the first cavity is a closed cavity. The reference probe comprises a first detection element. The first detection element comprises a first thermistor, and the first thermistor is located in the first cavity. The thermal conductivity of a gas in the first cavity is higher or lower than that of the air. The reference probe of the present application is applied to a gas detection device. The gas detection device is provided with a first cavity and a second cavity. The first cavity is a closed cavity, and the second cavity is an open cavity. There is a significant difference in the thermal conductivities of a gas in the closed cavity and a gas to be tested. Since the difference in gas thermal conductivity is proportional to the difference in gas concentration, when the concentration difference between the gas in the closed cavity and the gas to be tested increases, the relative concentration of the gas to be tested rises, thereby improving the detection accuracy of the gas detection device.

Description

Reference probes and gas detection devices

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on July 28, 2023, with application number 202310943536.6 and invention name “Reference probe and gas detection device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of measurement technology, and in particular to a reference probe and a gas detection device. Background Art

[0003] The gas detection device includes a first cavity, a second cavity, a first detection element, a second detection element and a circuit board. The first housing has a first cavity, and the second housing has a second cavity, wherein the second cavity is ventilated and connected to the external environment. The first cavity is a closed cavity, and both cavities contain a thermistor-type sensing element. Traditional closed cavities are generally injected with air or nitrogen with the same thermal conductivity as air. When the cavity is opened to enter the gas to be detected, when there is a difference in the thermal conductivity of the two chambers, a difference will appear in the two thermistor-type sensing elements. When the difference reaches a certain size, the sensor device will issue an alarm. One of the requirements of the gas detection device is to be able to accurately detect the gas to be detected. Therefore, it is necessary to improve the accuracy of the sensor device in detecting the gas to be detected.

[0004] Summary of the Invention

[0005] In order to solve the above technical problems, the present application provides a reference probe capable of improving the detection accuracy of a gas detection device and a gas detection device with high accuracy.

[0006] A first aspect of the present application provides a reference probe for gas detection, the reference probe having a first cavity, the first cavity being a sealed cavity, the reference probe including a first detection element, the first detection element including a first thermistor, the first thermistor being located in the first cavity;

[0007] The thermal conductivity of the gas in the first cavity is higher or lower than the thermal conductivity of air.

[0008] The reference probe provided in the first aspect of the present application has a thermal conductivity of the gas in the first cavity that is higher or lower than the thermal conductivity of air. The reference probe of the present application can be used for gas detection to be more clearly compared with the detection probe, thereby improving the detection accuracy of the gas detection device.

[0009] A second aspect of the present application provides a gas detection device, the gas detection device comprising a first cavity and a second cavity, the first cavity being a closed cavity, and the second cavity being in communication with the external gas of the gas detection device;

[0010] The gas detection device includes a first thermistor and a second thermistor, the first thermistor is located in the first cavity, and the second thermistor is located in the second cavity;

[0011] The thermal conductivity of the gas in the first cavity is higher or lower than the thermal conductivity of air.

[0012] The gas detection device provided in the second aspect of the present application includes a first cavity and a second cavity, the first cavity is a closed cavity, and the second cavity is an open cavity. A gas with a thermal conductivity different from that of air is injected into the closed cavity, so that a large difference occurs in the thermal conductivity of the gas in the closed cavity and the gas to be measured. Since the difference in gas thermal conductivity is proportional to the difference in gas concentration, the greater the difference in concentration between the gas in the closed cavity and the gas to be measured, the higher the relative concentration of the gas to be measured will be, and the detection accuracy of the gas detection device will be improved.

[0013] A third aspect of the present application provides a gas detection device, comprising an outer shell, a circuit board, and a reference probe, wherein the reference probe is electrically connected to the circuit board, and the circuit board is at least partially located within the outer shell;

[0014] The reference probe includes a first shell and a first thermistor. The first shell has a first cavity, which is a closed cavity. The first thermistor is located in the first cavity. The thermal conductivity of the gas in the first cavity is higher or lower than the thermal conductivity of air.

[0015] The reference probe included in the gas detection device provided in the third aspect of the present application has a closed cavity, and the thermal conductivity of the gas in the closed cavity is higher or lower than the thermal conductivity of air, which is conducive to improving the detection accuracy of the gas detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a schematic diagram of an explosion of a gas detection device provided in one embodiment of the present application;

[0017] FIG2 is a schematic diagram of an explosion of a gas detection device provided in one embodiment of the present application;

[0018] FIG3 is a cross-sectional schematic diagram of a gas detection device provided in one embodiment of the present application;

[0019] FIG4 is a schematic diagram of an explosion of a gas detection device provided in one embodiment of the present application;

[0020] FIG5 is a schematic diagram of a gas detection device provided in one embodiment of the present application;

[0021] FIG6 is a cross-sectional schematic diagram of the gas detection device provided in FIG5 ;

[0022] FIG7 is a schematic cross-sectional view of a gas detection device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0024] It should be understood that the embodiments described are only a portion of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] At present, the relevant gas detection device will have a detection probe 2 and a reference probe 1. The detection probe 2 includes a second detection element 21. The detection probe 2 has a second cavity 22. The second cavity 22 is an open cavity. The reference probe 1 includes a first detection element 11. The reference probe 1 has a first cavity 12. The first cavity 12 is a sealed cavity. The first cavity 12 is generally injected with air. When the gas to be detected enters the first cavity 12, the difference between the second detection element 21 and the first detection element 11 will cause the electrical signal to change, thereby triggering the gas detection device 7 to issue an alarm prompt. The detection accuracy of the gas detection device 7 is crucial.

[0026] The present application provides a reference probe 1 that can improve the detection accuracy of a gas detection device 7. In one embodiment, as shown in FIG1 , the reference probe 1 has a first cavity 12, which is a sealed cavity. The reference probe 1 includes a first detection element 11, which includes a first thermistor 111. The first detection element 11 is at least partially located in the first cavity 12, and the first thermistor 111 is located in the first cavity 12. The thermal conductivity of the gas in the first cavity 12 is higher or lower than the thermal conductivity of air.

[0027] In order to improve the detection accuracy of the gas detection device 7, the present application provides a gas detection device 7, which has a first cavity 12 and a second cavity 22, the first cavity 12 is a closed cavity, and the second cavity 22 is connected to the external gas of the gas detection device 7; the gas detection device 7 includes a first thermistor 111 and a second thermistor 211, the first thermistor 111 is located in the first cavity 12, and the second thermistor 211 is located in the second cavity 22, and the thermal conductivity of the gas in the first cavity 12 is higher or lower than the thermal conductivity of the air.

[0028] Furthermore, the thermal conductivity of the gas in the first chamber 12 is lower than the thermal conductivity of air, and the gas in the first chamber 12 includes at least one of chlorine, sulfur dioxide, difluoromethane, hydrogen sulfide, carbon dioxide, nitric oxide, propane, argon, ethylene, water vapor, ethane, 2,3,3,3-tetrafluoropropylene or a mixture of difluoromethane and 2,3,3,3-tetrafluoropropylene; or, the thermal conductivity of the gas in the first chamber 12 is higher than the thermal conductivity of air, and the gas in the first chamber 12 includes at least one of methane, helium or hydrogen.

[0029] The detection accuracy of the gas detection device 7 is related to the gas concentration. The greater the difference in thermal conductivity between the gas in the first chamber 12 of the gas detection device 7 and the gas to be detected in the second chamber 22, that is, the greater the concentration difference between the gas in the first chamber 12 and the gas to be detected, the higher the relative concentration of the gas to be detected. The higher the concentration of the gas to be detected, the higher the detection accuracy of the gas detection device 7. Therefore, the difference between the thermal conductivity of the gas in the first chamber 12 and the thermal conductivity of the gas to be detected is greater than 10mW / m·K. For example, R32 (chemical name: difluoromethane, a halogenated hydrocarbon, chemical formula: CH2F2) refrigerant is used in air-conditioning systems. This refrigerant will not damage the atmospheric ozone layer, but R32 is slightly flammable and can form an explosive mixture when mixed with air. There is a risk of combustion and explosion when exposed to heat sources or open flames, posing a safety hazard. At this time, the gas detection device 7 provided in the present application can be used in an air-conditioning system. When at least one of methane, helium or hydrogen is injected into the first chamber 12, the thermal conductivity of the gas in the first chamber 12 is greatly different from that of R32, and the concentration of R32 gas is relatively increased. The gas detection device 7 can detect more accurately, further reducing safety hazards to ensure the safety of the air-conditioning system.

[0030] In one embodiment, as shown in Figure 4, the gas detection device 7 includes an outer shell 80, a circuit board 6, a detection probe 2 and the reference probe 1, wherein the circuit board 6, the detection probe 2 and the reference probe 1 are all located inside the outer shell 80, wherein the outer shell 80 has a vent 81; the reference probe 1 includes a first shell 71 and a first thermistor 111, and the detection probe 2 includes a second shell 72 and a second thermistor 211, and the first thermistor 111 and the second thermistor 211 are both electrically connected to the circuit board 6.

[0031] Furthermore, in one embodiment, the first thermistor 111 and the second thermistor 211 are both negative temperature coefficient (NTC) thermistor chips, thereby facilitating component selection.

[0032] The gas detection device 7 of the present application is electrically connected to the circuit board 6 and can be used in air-conditioning systems such as household air conditioners and car air conditioners, and can also be used in refrigeration equipment such as refrigerators. The air-conditioning system may include a refrigerant conveying component (such as a pipe connecting a heat exchanger or an internal channel of a heat exchanger, etc.) for conveying refrigerant (such as R32, R454B, etc.). When the thermal conductivity of the gas injected into the reference probe 1 is higher or lower than the thermal conductivity of the air, the gas detection device 7 prepared using the reference probe 1 of the present application can not only be used to measure the gas concentration around various components of the air-conditioning system, but also more accurately determine whether there is a refrigerant leak or other phenomena, which is conducive to eliminating safety hazards. Of course, in some other embodiments, the gas detection device 7 can also be used to detect other types of gases.

[0033] For example, the gas detection device 7 is used to detect the gas concentration in its surrounding environment and issue an alarm. The detection probe 2 in the gas detection device 7 can collect the gas concentration signal, and compare the collected gas concentration signal with the gas concentration signal in the reference probe 1. When the difference reaches the set data, the signal will be transmitted to the processing unit of the gas detection device 7 and processed by the processing unit of the gas detection device 7. In this way, the gas detection device 7 and the air-conditioning system will take corresponding countermeasures, such as taking alarm processing, to ensure the safety of the air-conditioning system.

[0034] The second shell 72 has a through hole 721, which is connected to the second cavity 22, and the through hole 721 is connected to the external gas of the gas detection device 7; in order to enable the second thermistor 211 to sense the changes in the gas to be detected more quickly and make rapid detection, in one embodiment, as shown in Figures 3 and 4, the second thermistor 211 is at least partially aligned with the through hole 721, and the air vent 81 is at least partially aligned with the through hole 721.

[0035] To improve the detection accuracy of the gas detection device 7, the gas detection device 7 further includes a waterproof and breathable membrane 722 to prevent impurities such as moisture and dust from entering the second cavity 22 and affecting the detection accuracy. In some embodiments, as shown in FIG2 , the waterproof and breathable membrane 722 is connected to the second housing 72 and covers the through-hole 721. The waterproof and breathable membrane 722 may include a waterproof and breathable porous material attached to a polyester fiber fabric through a specific process. The pore size of the waterproof and breathable membrane is at the nanometer level, thereby achieving waterproof, dustproof, and breathable properties. The use of the waterproof and breathable membrane 722 also extends the service life of the product.

[0036] In some embodiments, the gas detection device 7 has a first direction H, and a plane perpendicular to the first direction H is defined as a projection plane. Along the first direction H, the orthographic projection of the hole wall corresponding to the through hole 721 on the projection plane is a first projection, and the orthographic projection of the waterproof and breathable membrane 722 on the projection plane is a second projection. The first projection is located within the outer contour of the second projection.

[0037] In order to facilitate the installation of the detection probe 2 and the reference probe 1 in the outer shell 80, in one embodiment, as shown in Figure 5, the first shell 71 and the second shell 72 are integrated into one piece, and the outer shell 70 includes a connecting wall 73, and the first shell 71 and the second shell 72 are both connected to the connecting wall 73.

[0038] To reduce the impact of external temperature on the first cavity 12 and, in turn, the detection accuracy of the gas detection device 7, in one embodiment, as shown in FIG6 , a gap is provided between the first shell 71 and the second shell 72. Furthermore, a spacing groove 74 is provided between the first shell 71 and the second shell 72. The first shell 71 includes a top wall 713 and side walls 714, both of which are located at the periphery of the first cavity 12. The gas detection device 7 has a first direction H, which is parallel to the height direction of the gas detection device 7. Along the first direction H, at least a portion of the side wall 714 is closer to the first thermistor 111 relative to the top wall 713. The connecting wall 73 is spaced away from the top wall 713 relative to the spacing groove 74. The dimension of the spacing groove 74 along the first direction is greater than the dimension of the connecting wall 73 along the first direction. Thus, the spacing groove 74 isolates heat conduction between the shared partition wall of the first shell 71 and the second shell 72, thereby further improving the detection accuracy of the gas detection device 7.

[0039] In one embodiment, as shown in Figure 6 , the dimension of the spacing groove 74 in the first direction H of the gas detection device 7 is h1, and the dimension of the connecting wall 73 in the first direction H of the gas detection device 7 is h2, where h1 and h2 satisfy the following relationship: 2≤h1 / h2≤4. When the dimension of the spacing groove 74 in the first direction H is at least twice and less than four times the dimension of the connecting wall 73 in the first direction H, heat transfer between the first cavity 12 and the second cavity 22 is further reduced, thereby further improving the detection accuracy of the gas detection device 7 while also ensuring the connection strength of the spacing groove 74. Preferably, h1 / h2 = 3, which achieves both reduced heat transfer between the first cavity 12 and the second cavity 22 and a sufficiently strong connection between the first shell 71 and the second shell 72.

[0040] In one embodiment, the first detection element 11 includes a first base 112, the first base 112 is provided with a first step 1121, and along the first direction H, the first step 1121 protrudes from the first base 112 toward the top wall 713; the second detection element 21 includes a second base 212, the second base 212 is provided with a second step 2121, and along the first direction H, the second step 2121 protrudes from the second base 212 toward the top wall 713.

[0041] The first shell 71 includes a first flange portion 715. Along the first direction H, the first flange portion 715 is close to the first base 112 relative to the first thermistor 111. The second shell 72 includes a second flange portion 723. Along the first direction H, the second flange portion 723 is close to the second base 212 relative to the top wall 713.

[0042] For easy installation, the first flange portion 715 is connected to the wall of the first step 1121, and the second flange portion 723 is connected to the wall of the second step 2121, wherein the connection method includes a sealed connection, and the sealed connection method includes welding or sealant connection or connection through a sealing ring.

[0043] The first detection element 11 includes a first conductive portion 113 and a first lead 114. The first thermistor 111 is electrically connected to the first lead 114, which is in turn electrically connected to the first conductive portion 113. The first conductive portion 113 extends through the first base 112 and is fixedly connected to the first base 112. Along the first direction H, the first conductive portion 113 has a first end 1131, which is located closer to the top wall 713 relative to the first base 112. In related art, the first thermistor 111 of the gas detection device 7 is positioned away from the first base 112 relative to the first end 1131. During the manufacture of the gas detection device 7, the first housing 71 can easily contact the first thermistor 111, thereby affecting detection accuracy. Therefore, to improve the detection accuracy of the gas detection device 7, in one embodiment, as shown in Figures 7 and 3, the first thermistor 111 is no higher than the first end 1131 along the first direction H of the gas detection device 7.

[0044] In some embodiments, the first conductive portion 113 includes a first sub-conductive portion 1132 and a second sub-conductive portion 1133. The first sub-conductive portion 1132 has a first sub-end 1134, and the second sub-conductive portion 1133 has a second sub-end 1135. Along the first direction H of the gas detection device 7, the first sub-end 1134, the second sub-end 1135, and the first thermistor 111 are all located on the same side of the first base 112, with the first thermistor 111 at least partially located between the first sub-end 1134 and the second sub-end 1135. Alternatively, along the first direction H of the gas detection device 7, the first sub-end 1134 and the second sub-end 1135 are both located away from the first base 112 relative to the first thermistor 111. This helps reduce the height of the first detection element 11 and reduces the risk of the first thermistor 11 contacting the first housing 71 during assembly of the first detection element 11 with the first housing 71, causing the first detection element 11 to fail.

[0045] Meanwhile, the second detection element 21 includes a second conductive portion 213 and a second lead 214. The second thermistor 211 is electrically connected to the second lead 214, which is in turn electrically connected to the second conductive portion 213. Along the first direction H, the second conductive portion 213 has a second end 2131, which is closer to the top wall 713 relative to the second base 212. Along the first direction H of the gas detection device 7, the second thermistor 211 is no higher than the second end 2131. The circuit board 6 has a first opening 61 and a second opening 62. The first conductive portion 113 is electrically connected to the wall of the first opening 61, and the second conductive portion 213 is electrically connected to the wall of the second opening 62.

[0046] In some embodiments, the gas detection device 7 of the present application includes an outer shell 80, a circuit board 6, and a reference probe 1. The reference probe 1 is electrically connected to the circuit board 6, and the circuit board 6 is at least partially located within the outer shell 80. The reference probe 1 includes a first shell 71 and a first thermistor 111. The first shell 71 has a first cavity 12, which is a closed cavity. The first thermistor 111 is located in the first cavity 12. The thermal conductivity of the gas in the first cavity 12 is higher or lower than the thermal conductivity of air.

[0047] In some embodiments, the gas detection device 7 includes the detection probe 2 described above, which is electrically connected to the circuit board 6. At least a portion of the detection probe 2 and at least a portion of the reference probe 1 are both located within the outer shell 80. The detection probe 2 and the reference probe 1 are separately mounted on the circuit board 6, with a gap between them.

[0048] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A reference probe for gas detection, characterized in that: The reference probe has a first cavity, the first cavity is a closed cavity, the reference probe includes a first detection element, the first detection element includes a first thermistor, and the first thermistor is located in the first cavity; The thermal conductivity of the gas in the first chamber is higher or lower than the thermal conductivity of air.

2. The reference probe according to claim 1, characterized in that: The thermal conductivity of the gas in the first cavity is lower than that of air, and the gas in the first cavity comprises at least one of chlorine, sulfur dioxide, difluoromethane, 2,3,3,3-tetrafluoropropylene or a mixture of difluoromethane and 2,3,3,3-tetrafluoropropylene; or, The thermal conductivity of the gas in the first cavity is higher than that of air, and the gas in the first cavity includes at least one of methane, helium or hydrogen.

3. The reference probe according to claim 1, characterized in that: The difference between the thermal conductivity of the gas in the first cavity and the thermal conductivity of the detected gas is greater than 10 mW / m·K.

4. The reference probe according to any one of claims 1 to 3, characterized in that: The first thermistor is a negative temperature coefficient thermistor.

5. A gas detection device, characterized in that: The gas detection device comprises a first cavity and a second cavity, the first cavity is a closed cavity, and the second cavity is connected to the external gas of the gas detection device; The gas detection device comprises a first thermistor and a second thermistor, the first thermistor is located in the first cavity, and the second thermistor is located in the second cavity; The thermal conductivity of the gas in the first chamber is higher or lower than the thermal conductivity of air.

6. The gas detection device according to claim 5, characterized in that: The thermal conductivity of the gas in the first chamber is lower than that of air, and the gas in the first chamber includes at least one of chlorine, sulfur dioxide, difluoromethane, 2,3,3,3-tetrafluoropropylene or a mixture of difluoromethane and 2,3,3,3-tetrafluoropropylene; or, The thermal conductivity of the gas in the first cavity is higher than that of air, and the gas in the first cavity includes at least one of methane, helium or hydrogen.

7. The gas detection device according to claim 5, characterized in that: The gas detection device comprises a first shell and a second shell, the first shell having the first cavity, the second shell having the second cavity and a through hole, the through hole being in communication with the second cavity, and the through hole being in communication with external gas of the gas detection device; There is a distance between the first shell and the second shell; or, The first shell and the second shell are an integral piece, the outer shell comprises a connecting wall, and the first shell and the second shell are both connected to the connecting wall.

8. The gas detection device according to claim 7, characterized in that: A spacing groove is provided between the first shell and the second shell; The first housing comprises a top wall and a side wall, wherein the top wall and the side wall are both located at the periphery of the first cavity; the gas detection device has a first direction, and along the first direction, the side wall is at least partially close to the first thermistor relative to the top wall; The connecting wall is away from the top wall relative to the spacing groove, and a dimension of the spacing groove along the first direction is greater than a dimension of the connecting wall along the first direction.

9. The gas detection device according to claim 8, characterized in that: The dimension of the spacing groove along the first direction is H1, and the dimension of the connecting wall along the first direction is H2, wherein H1 and H2 satisfy the following relationship: 2≤H1 / H2≤4.

10. The gas detection device according to claim 7, characterized in that: The gas detection device comprises an outer shell, a circuit board, a detection probe and a reference probe, wherein the circuit board, the detection probe and the reference probe are all located inside the outer shell; The reference probe includes the first shell and the first thermistor, the detection probe includes the second shell and the second thermistor, and the first thermistor and the second thermistor are both electrically connected to the circuit board.

11. The gas detection device according to claim 5, characterized in that: The first thermistor is a negative temperature coefficient thermistor, and the second thermistor is a negative temperature coefficient thermistor.

12. A gas detection device, characterized in that: It comprises an outer shell, a circuit board and a reference probe, wherein the reference probe is electrically connected to the circuit board, and the circuit board is at least partially located inside the outer shell; The reference probe comprises a first shell and a first thermistor, wherein the first shell has a first cavity, the first cavity is a closed cavity, the first thermistor is located in the first cavity, The thermal conductivity of the gas in the cavity may be higher or lower than the thermal conductivity of air.

13. The gas detection device according to claim 12, characterized in that: The thermal conductivity of the gas in the first cavity is lower than that of air, and the gas in the first cavity comprises at least one of chlorine, sulfur dioxide, difluoromethane, 2,3,3,3-tetrafluoropropylene or a mixture of difluoromethane and 2,3,3,3-tetrafluoropropylene; or, The thermal conductivity of the gas in the first cavity is higher than that of air, and the gas in the first cavity includes at least one of methane, helium or hydrogen.

14. The gas detection device according to claim 12, characterized in that: The difference between the thermal conductivity of the gas in the first cavity and the thermal conductivity of the detected gas is greater than 10 mW / m·K.

15. The gas detection device according to claim 12, characterized in that: The reference probe includes a first detection element, the first detection element includes the first thermistor, a first conductive part, a first lead and a first base, the first thermistor is electrically connected to the first lead, the first lead is electrically connected to the first conductive part, and the first conductive part passes through the first base; The first conductive portion includes a first sub-conductive portion and a second sub-conductive portion, the first sub-conductive portion has a first sub-end, and the second sub-conductive portion has a second sub-end; along a first direction of the gas detection device, the first sub-end, the second sub-end and the first thermistor are all located on the same side of the first base, and the first thermistor is at least partially located between the first sub-end and the second sub-end; or, the first sub-end and the second sub-end are both far away from the first base relative to the first thermistor.

16. The gas detection device according to claim 12, characterized in that: The gas detection device comprises a detection probe, and the detection probe is electrically connected to the circuit board; The detection probe comprises a second shell and a second thermistor, the second shell has a second cavity, the second cavity is an open cavity, and the second thermistor is located in the second cavity; The first thermistor and the second thermistor are both negative temperature coefficient thermistors.

17. The gas detection device according to claim 16, characterized in that: The second shell has a through hole, the through hole is connected to the second cavity, and the through hole is connected to the external gas of the gas detection device; The gas detection device comprises a waterproof and breathable membrane, the waterproof and breathable membrane and the second shell The waterproof and breathable membrane at least partially covers the through hole.

18. The gas detection device according to claim 17, characterized in that: The gas detection device has a first direction, and a plane perpendicular to the first direction is defined as a projection plane. Along the first direction, the orthographic projection of the hole wall corresponding to the through hole on the projection plane is a first projection, and the orthographic projection of the waterproof and breathable membrane on the projection plane is a second projection. The first projection is located within the outer contour of the second projection.

19. The gas detection device according to claim 16, characterized in that: The detection probe and the reference probe are respectively installed on the circuit board, and there is a distance between the detection probe and the reference probe.

20. The gas detection device according to any one of claims 5 to 19, characterized in that: The gas detection device is used to detect refrigerant leakage.

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