Reference probe and gas detection device
By injecting gases with different thermal conductivity into the closed chamber of the gas detection device, the problem of insufficient gas detection accuracy in the prior art is solved, and higher detection accuracy and more accurate gas concentration judgment are achieved.
Patent Information
- Application Number
- CN202310943536.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-28
- Publication Date
- 2025-02-14
AI Technical Summary
When the existing gas detection device detects the gas to be tested, the accuracy is insufficient, making it difficult to accurately detect the concentration of the gas.
By injecting gas with a thermal conductivity higher or lower thermal conductivity into the closed chamber of the gas detection device, the thermal conductivity difference from the gas to be measured is large, thereby improving the detection accuracy.
By increasing the difference in thermal conductivity of the gas, the detection accuracy of the gas detection device is improved, and the concentration of the gas to be tested can be more accurately judged, reducing safety hazards.
Smart Images
Figure CN119438332A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of measurement technology, and in particular to a reference probe and a gas detection device. Background Art
[0002] 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 shell has a first cavity, and the second shell 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 have a thermistor-type sensing element. Air or nitrogen with the same thermal conductivity as air is generally injected into the traditional closed cavity. 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, there will be a difference between 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 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. Summary of the invention
[0003] 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.
[0004] 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 closed cavity, the reference probe comprising a first detection element, the first detection element comprising a first thermistor, and the first detection element being located in the first cavity;
[0005] The thermal conductivity of the gas in the first chamber is higher or lower than the thermal conductivity of air.
[0006] The reference probe provided in the first aspect of the present application has a thermal conductivity of 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 and can be more clearly compared with the detection probe, thereby improving the detection accuracy of the gas detection device.
[0007] A second aspect of the present application provides a gas detection device, the gas detection device having a first cavity and a second cavity, the first cavity being a closed cavity, and the second cavity being in communication with external gas of the gas detection device;
[0008] 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;
[0009] The thermal conductivity of the gas in the first chamber is higher or lower than the thermal conductivity of air.
[0010] 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 having a thermal conductivity different from that of air is injected into the closed cavity, so that a large difference appears in the thermal conductivity between 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. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 An explosion diagram of a gas detection device provided in one embodiment of the present application;
[0012] Figure 2 An explosion diagram of a gas detection device provided in one embodiment of the present application;
[0013] Figure 3 A cross-sectional schematic diagram of a gas detection device provided in one embodiment of the present application;
[0014] Figure 4 An explosion diagram of a gas detection device provided in one embodiment of the present application;
[0015] Figure 5 A schematic diagram of a gas detection device provided in one embodiment of the present application;
[0016] Figure 6 for Figure 5 A cross-sectional schematic diagram of a gas detection device is provided;
[0017] Figure 7 A cross-sectional schematic diagram of a gas detection device provided in one embodiment of the present application. DETAILED DESCRIPTION
[0018] 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.
[0019] It should be clear that the described embodiments are only part of the embodiments of this application, not all of the embodiments. 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.
[0020] At present, the relevant gas detection device has 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, and 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, and 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 an alarm prompt from the gas detection device 7. The detection accuracy of the gas detection device 7 is crucial.
[0021] The present application provides a reference probe 1 that can improve the detection accuracy of a gas detection device 7. In one embodiment, referring to Figure 1 As shown, the reference probe 1 has a first cavity 12, the first cavity 12 is a closed cavity, the reference probe 1 includes a first detection element 11, the first detection element 11 includes a first thermistor 111, and the first detection element 11 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 the air.
[0022] 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.
[0023] Further, the thermal conductivity of the gas in the first cavity 12 is lower than the thermal conductivity of air, and the gas in the first cavity 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 cavity 12 is higher than the thermal conductivity of air, and the gas in the first cavity 12 includes at least one of methane, helium or hydrogen.
[0024] 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 will be. 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 / mK. For example, R32 (chemical name is difluoromethane, a halogenated hydrocarbon, chemical formula is CH2F2) refrigerant is used in the air-conditioning system. 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 encountering heat sources or open flames, which poses 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.
[0025] In one embodiment, if Figure 4 As shown, 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, 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.
[0026] Furthermore, in one embodiment, both the first thermistor 111 and the second thermistor 211 are NTC thermistor chips, thereby facilitating component selection.
[0027] 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 with the reference probe 1 of the present application can not only be used for the gas concentration around each component of the air-conditioning system, but also more accurately determine whether there is a phenomenon such as refrigerant leakage, 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.
[0028] 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, so that the gas detection device 7 and the air-conditioning system will take corresponding countermeasures, such as taking alarm processing, to ensure the safe use of the air-conditioning system.
[0029] The second housing 72 has a through hole 721, which is connected to the second chamber 22, and the through hole 721 is connected to the external gas of the gas detection device 7; in order to make the second thermistor 211 sense the change of the gas to be detected more quickly and make a rapid detection, in one embodiment, as Figure 3 and Figure 4 As shown, the second thermistor 211 is at least partially aligned with the through hole 721 , and the air hole 81 is at least partially aligned with the through hole 721 .
[0030] In order to improve the detection accuracy of the gas detection device 7, the second housing 72 further includes a waterproof and breathable membrane 722 to prevent impurities such as moisture or dust from entering the second cavity 22 to affect the detection accuracy. In some embodiments, refer to Figure 2 As shown, the waterproof and breathable membrane 722 covers the through hole 721. The waterproof and breathable membrane 722 may include a waterproof and breathable porous material attached to a polyester fiber cloth processed by a specific process, and the pore size thereof is at the nanometer level, so that it can play the role of being waterproof, dustproof and breathable. The use of the waterproof and breathable membrane 722 also extends the service life of the product.
[0031] In order to facilitate the installation of the detection probe 2 and the reference probe 1 in the outer shell 80, in one embodiment, Figure 5 As shown, the first shell 71 and the second shell 72 are an integral piece, and the housing 70 includes a connecting wall 73 , and the first shell 71 and the second shell 72 are both connected to the connecting wall 73 .
[0032] In order to reduce the influence of the external temperature on the first cavity 12, thereby affecting the detection accuracy of the gas detection device 7, in one embodiment, as Figure 6As shown, there is a spacing between the first shell 71 and the second shell 72; further, 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 a side wall 714, and the top wall 713 and the side wall 714 are both located at the periphery of the first cavity 12; the gas detection device 7 has a first direction H, and the first direction H is parallel to the height direction of the gas detection device 7. Along the first direction H, the side wall 714 is at least partially close to the first thermistor 111 relative to the top wall 713; the connecting wall 73 is away from the top wall 713 relative to the spacing groove 74, and the size of the spacing groove 74 along the first direction is greater than the size of the connecting wall 73 along the first direction, so that the spacing groove 74 isolates the 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.
[0033] In one embodiment, if Figure 6 As shown, the size of the spacing groove 74 in the first direction H of the gas detection device 7 is h1, and the size of the connecting wall 73 in the first direction H of the gas detection device 7 is h2, wherein h1 and h2 satisfy the following relationship: 2≤h1 / h2≤4. When the size of the spacing groove 74 in the first direction H is more than twice and less than four times the size of the connecting wall 73 in the first direction H, the 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 taking into account the connection strength of the spacing groove 74. Preferably, h1 / h2=3, which can reduce the heat transfer between the first cavity 12 and the second cavity 22, and the connection strength between the first shell 71 and the second shell 72 is strong enough.
[0034] 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 direction close to 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 direction close to the top wall 713.
[0035] The first shell 71 includes a first flange portion 715 , and 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 , and along the first direction H, the second flange portion 723 is close to the second base 212 relative to the top wall 713 .
[0036] 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.
[0037] 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. The first lead 114 is electrically connected to the first conductive portion 113. Along the first direction H, the first conductive portion 113 has a first end 1131. The first end 1131 is close to the top wall 713 relative to the first base 112. In the related art, the first thermistor 111 of the gas detection device 7 is far away from the first base 112 relative to the first end 1131. When the gas detection device 7 is manufactured, the first shell 71 is easy to hit the first thermistor 111, thereby affecting the detection accuracy. Therefore, in order to improve the detection accuracy of the gas detection device 7, in one embodiment, as shown in FIG. Figure 7 and Figure 3 As shown, along the first direction H of the gas detection device 7, the first thermistor 111 is not higher than the first end 1131. At the same time, 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, the second lead 214 is electrically connected to the second conductive portion 213, along the first direction H, the second conductive portion 213 has a second end 2131, and the second end 2131 is close 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 not higher than the second end 2131. Among them, the circuit board 6 has a first opening 61 and a second opening 62, the first conductive portion 113 is electrically connected to the hole wall of the first opening 61, and the second conductive portion 213 is electrically connected to the hole wall of the second opening 62.
[0038] 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 spirit 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 detection element 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 / mK.
4. 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.
5. The gas detection device according to claim 4, 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.
6. The gas detection device according to claim 4 or 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.
7. The gas detection device according to claim 6, 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.
8. The gas detection device according to claim 7, 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.
9. The gas detection device according to claim 6, 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.
10. The gas detection device according to claim 4, characterized in that: The first thermistor is an NTC thermistor, and the second thermistor is an NTC thermistor.