Gas detection device

Abstract

The invention relates to a gas detection device which comprises a circulating gas channel, gas flow generation equipment, at least one group of gas sensors, a protective layer and a permeable membrane, wherein the circulating gas channel is provided with or communicated with an interface used for being communicated with a to-be-detected gas environment; the gas flow generating equipment and the at least one group of gas sensors are connected in series in the circulating gas passage; the protective layer covers the interface and is used for pressing the permeable membrane and allowing gas to pass through; the permeable membrane covers the interface, is arranged on one side, deviating from the to-be-detected gas environment, of the protective layer, and is used for permeating the gas filtered by the protective layer; the gas detection device at least has the following beneficial effects that the defect of low response speed of a traditional diffusion type sensor is avoided, the problems of flow reduction and damage caused by high-load operation of a pump body due to direct suction of dusty gas in a pump suction manner are also avoided, and the gas detection device has the advantages of good dust resistance and high response speed.

Description

Technical Field

[0001] This invention relates to the field of detection or detection devices, and more specifically, to a gas detection device. Background Technology

[0002] Gas sensors, based on their detection principles, can be divided into telemetry sensors and contact detection sensors. Telemetry sensors are difficult to use in high-dust environments due to dust obstruction. Contact sensors require actual contact with the gas being measured and are classified into pump-suction and diffusion types according to different sampling methods. Pump-suction sensors use a pump to draw gas into the device, causing the gas to flow across the sensor surface and generate a response. Diffusion sensors do not use a pump; they rely on the gas concentration gradient to drive diffusion to the sensor surface for detection. Pump-suction and diffusion types are widely used in structures such as semiconductor gas sensors (resistive and hot-wire types), catalytic combustion sensors, photoionization sensors, electrochemical sensors, and infrared sensors.

[0003] In normal environments, the above methods of using gas sensors can meet the requirements; however, in high-dust environments, these two methods are insufficient to meet real-time gas sensing needs. For example, in high-dust pipelines, directly placing the gas sensor in the main pipeline often leads to maintenance difficulties. The high concentration of dust in the pipeline can easily impact the sensor surface, causing dust accumulation and sensor damage. Installation and replacement require disassembling the main pipeline, resulting in a large workload. If a bypass installation method is used for the gas sensor, when using a pump-suction sensor, a large amount of dust will be drawn in, greatly affecting the pump's lifespan. Filter materials often need to be replaced frequently, otherwise, problems such as reduced flow rate and pump damage due to high load operation will occur. If a diffusion sensor is used, there are drawbacks such as smaller bypass airflow, slower gas diffusion speed, and a significantly reduced sensor response speed. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a gas detection device with good dust resistance and fast response speed, which can be used for gas detection in various detection environments, especially suitable for the detection of relevant gases in high dust environments (such as pipelines with high dust content).

[0005] The objective of this invention is achieved through the following technical solution: Gas detection device, including: A recirculating airway, which has or is connected to an interface for connecting to the gas environment to be detected; An airflow generating device, which is connected in series in the circulating air duct, is used to generate circulating airflow in the circulating air duct; At least one set of gas sensors is connected in series in the recirculating airway; A protective layer, which covers the interface, is used to press the permeation membrane mentioned later and allow gas to pass through; A permeation membrane, which covers the interface and is placed on the side of the protective layer away from the gas environment to be detected, is used to permeate the gas filtered by the protective layer.

[0006] The gas detection device of the present invention has at least the following beneficial effects: By constructing a set of circulating gas channels outside the gas environment to be detected, and connecting the circulating gas channels to the gas environment through an interface, and placing a permeable membrane on the interface, the gas molecules that permeate through the permeable membrane can be rapidly transferred under the action of airflow in the circulating gas channels, thereby increasing the gas concentration gradient on both sides of the permeable membrane and accelerating the permeation rate of molecules into the circulating gas channels; under the action of airflow in the circulating gas channels, gas molecules can quickly enter the gas sensor, thereby improving the response speed of the gas sensor.

[0007] In addition, the protective layer and the permeable membrane effectively prevent dust from entering the entire gas detection device, ensuring the airflow rate of the circulating gas channel.

[0008] The gas detection device of the present invention avoids the disadvantage of slow response speed of traditional diffusion sensors, and also avoids the problems of reduced flow rate and damage to the pump body caused by directly sucking in dusty gas through pumping. It has the advantages of good dust resistance and fast response speed.

[0009] Furthermore, the interface is also covered by a purging assembly, which is arranged on the side of the permeation membrane away from the protective layer; the purging assembly has multiple gas passages that communicate with the permeation membrane, and all gas passages are connected to the circulation gas channel.

[0010] With the above configuration, the purging assembly guides the flow of gas molecules permeating through the membrane, facilitating the rapid entry of gas into the circulation channel.

[0011] Furthermore, in the purging assembly, one end of all the gas passages is covered by a permeable membrane and the other end is a closed end, and the inlet and outlet for connecting the circulating gas passages are all located on the closed end of the gas passages.

[0012] The above settings ensure stable flow between the purging assembly and the recirculating airway.

[0013] Furthermore, in the purging assembly, all air passages are connected to the recirculation airway in parallel.

[0014] Furthermore, the interface also includes a support component for supporting the permeation membrane, thereby ensuring the stability of the permeation membrane structure.

[0015] Furthermore, the support assembly includes a support ring adapted to the contour of the inner wall of the interface and a support mesh arranged within the support ring; the permeation membrane is supported on the mesh surface of the support mesh.

[0016] With the above setup, the support ring and the central support mesh can both support the permeable membrane and prevent the gas molecules from being blocked.

[0017] Furthermore, the interface is also equipped with a heat source to improve the permeability of the permeation membrane, and the heat source is arranged on the side of the permeation membrane close to the protective layer.

[0018] The above setup accelerates the permeation of gas molecules under the influence of heat.

[0019] Furthermore, the gas detection device contains multiple gas sensors connected in series in the circulating gas duct.

[0020] With the above settings, multiple gas sensors can be flexibly set up according to different detection needs.

[0021] For example, multiple gas sensors with different detection targets can be set up to detect different gases.

[0022] Alternatively, multiple gas sensors targeting the same target can be set up to obtain multiple sets of detection data, thereby improving detection accuracy.

[0023] Furthermore, the airflow generating device is a rotary vane pump, a diaphragm pump, a piezoelectric pump, or a fan.

[0024] Furthermore, the gas detection device also includes a set of containers with an interface provided on the containers; the circulating gas duct, the airflow generating device and all gas sensors are located inside the containers. Attached Figure Description

[0025] Figure 1 A schematic diagram of the gas detection device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the support component structure provided in an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the installation relationship between the support component and the permeation membrane provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a first embodiment of the purging assembly of the present invention; Figure 5 This is a schematic diagram of the structure of a second embodiment of the purging assembly of the present invention; Figure 6 This is a schematic diagram of the structure of the purging assembly of the present invention in embodiment three; Figure 7 This is a dynamic response diagram of the sensor of the gas detection device of the present invention when it detects the characteristic gas produced by smoldering cotton; The attached diagram lists the components represented by each number as follows: 1. Circulating airway; 10. Airflow generating device; 11. Gas sensor; 2. Container; 20. Interface; 3. Protective layer; 4. Permeable membrane; 5. Purge assembly; 50. Gas path; 500. Inlet; 501. Outlet; 51. Housing; 52. Partition; 6. Support assembly; 60. Support ring; 61. Support mesh; 7. Heat source; a. Gas environment to be detected. Detailed Implementation

[0026] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0027] Reference Figure 1 This invention provides a gas detection device, including a circulating gas channel 1, a protective layer 3, and a permeable membrane 4.

[0028] The circulating airway 1 has its own interface 20 or is connected to the interface 20 of the external structure. The function of the interface 20 is to connect with the gas environment a to be detected, so that the circulating airway 1 can be connected with the gas environment a to be detected through the interface 20.

[0029] The circulating air passage 1 is equipped with an airflow generating device 10, which drives the gas to circulate within the circulating air passage 1.

[0030] In addition, at least one set of gas sensors 11 is provided on the circulating airway 1, that is, the target gas detected by the gas sensors 11 is located inside the circulating airway 1.

[0031] Reference Figure 1 A protective layer 3 and a permeable membrane 4 are covered on the interface 20. The function of the protective layer 3 is to press the permeable membrane 4 and allow gas to pass through, so that the gas in the gas environment a to be detected can enter the circulation channel 1 along the interface 20. The permeable membrane 4 is arranged on the side of the protective layer 3 away from the gas environment a to be detected, and is used to permeate the gas filtered by the protective layer 3. That is, the gas in the gas environment a to be detected needs to be processed by the protective layer 3 and the permeable membrane 4 in sequence before entering the circulation channel 1.

[0032] The airflow within the circulating airway 1 allows gas molecules to pass rapidly through the permeation membrane 4 without generating macroscopic airflow.

[0033] Therefore, the most basic gas detection device constructed using the above structures can achieve the following objectives: First, a set of circulating gas channels 1 is set outside the gas environment a to be detected, which is equivalent to constructing a detection bypass structure. The circulating gas channels 1 are connected to the gas environment a to be detected through interface 20. A permeable membrane 4 is set on interface 20. Under the action of airflow in the circulating gas channels 1, the gas molecules that permeate through the permeable membrane 4 can be quickly transferred, thereby increasing the gas concentration gradient on both sides of the permeable membrane 4. This can accelerate the permeation rate of molecules into the circulating gas channels 1, which can make the gas molecules in the gas environment a to be detected diffuse quickly into the circulating gas channels 1. Since the gas molecules do not easily generate macro airflow through the permeable membrane 4, it also avoids the disadvantage of the traditional gas detection device that uses a pump to directly suck in a large amount of dust.

[0034] Then, under the action of airflow in the circulating airway 1, gas molecules are rapidly introduced into the gas sensor 11, thereby improving the response speed of the gas sensor 11.

[0035] When the gas concentration in the gas environment a to be detected decreases, the concentration inside the circulating airway 1 is higher than that outside, and the gas to be detected can be discharged in reverse.

[0036] What is easy to understand is that the so-called gas environment 'a' in the text refers to the spatial environment in which the gas being detected exists. This can be a closed environment such as inside a pipe or a warehouse, or an open environment such as outdoors.

[0037] The technical feature of covering mentioned in the text (such as the protective layer 3 and the permeation membrane 4 covering the interface 20 as described above) means that all gas introduced into the circulating airway 1 through the interface 20 must pass through the protective layer 3 and the permeation membrane 4, and does not limit the direct physical contact between the protective layer 3 and the interface 20 or between the permeation membrane 4 and the interface 20.

[0038] In addition, the permeation membrane 4 mentioned in the text is generally 10μm to 100μm thick, and the material can be organic materials such as polydimethylsiloxane (PDMS) film, polyethylene (PE) film, and polypropylene (PP) film, which can be selected according to the type of gas to be detected.

[0039] Therefore, in fact, one or both of the protective layer 3 and the permeable membrane 4 can be directly installed on the interface 20; or, one or both of the protective layer 3 and the permeable membrane 4 can be indirectly installed on the interface 20 through other external structures.

[0040] The aforementioned airflow generating device 10 can be a rotary vane pump, diaphragm pump, piezoelectric pump, or fan, etc. Those skilled in the art can also select other airflow generating and driving structures based on factors such as the overall size of the gas detection device and the airflow size in the circulating airway 1, which will not be listed here.

[0041] Furthermore, the shape of the aforementioned interface 20 can be circular, elliptical, triangular, quadrilateral, pentagonal, T-shaped, cross-shaped, or other irregular shapes, without limitation, as long as the structural components installed in the interface 20 are adapted to the outline of the interface 20.

[0042] In addition, the protective layer 3 can be made of materials such as glass fiber or filter cloth.

[0043] Furthermore, the gas detection device of the present invention can be used for gas detection in gas environments a containing dust and those not containing dust, and is particularly suitable for gas environments a with high dust content.

[0044] The following text will use a high-dust-content conveying pipeline as an example of the gas environment to be detected, and will elaborate on the detailed structure and working principle of the gas detection device of the present invention.

[0045] Based on the aforementioned gas detection device, in order to further enhance the permeation rate of gas molecules through the permeation membrane 4, in some embodiments, a purge assembly 5 is also covered on the interface 20. The purge assembly 5 is arranged on the side of the permeation membrane 4 away from the protective layer. The purge assembly 5 has multiple gas passages 50 that communicate with the permeation membrane 4, and all gas passages 50 are connected to the circulation gas channel 1. Through the physical gas passages 50, the purge assembly 5 can provide a guiding effect for the flow of gas molecules that permeate from the permeation membrane 4, so that the gas can quickly enter the circulation gas channel 1.

[0046] The so-called air passage 50 refers to several physical channels that divide the interior of the housing 51 by the partition 52; the housing 51 can be a structure that is set separately in the interface 20, in which case the housing 51 is sealed with the inner wall of the interface 20; or, the housing 51 can be the interface 20 itself, which is not limited here.

[0047] In the purging assembly 5, one end of all the air passages 50 is covered by the permeation membrane 4 and the other end is a closed end. The inlet 500 and outlet 501 used to connect the circulating air passage 1 are both opened on the closed end of the air passage 50. Each group of air passages 50 has a certain depth in the extension direction of the interface 20.

[0048] Reference Figure 4 As one embodiment of the purging assembly 5, multiple air passages 50 are divided within the housing 51 by several intersecting partitions 52. Each air passage 50 has an independent inlet 500 and a common set of outlets 501 at the closed end of the purging assembly 5.

[0049] Reference Figure 5 As a second embodiment of the purging assembly 5, several parallel baffles 52 are divided within the housing 51 to form multiple independent air passages 50. Each air passage 50 has an independent inlet 500 and an independent outlet 501 at the closed end of the purging assembly 5.

[0050] Reference Figure 6 As a third embodiment of the purging assembly 5, several parallel baffles 52 divide the housing 51 to form multiple independent air passages 50; a second set of baffles 52 is also provided in the internal space of the housing 51 where each set of air passages 50 is located. One end of the second set of baffles 52 is closed and connected to the housing 51, and the other end is left with a gap, so as to divide the space where each set of independent air passages 50 is located into two cavities that can communicate with each other. One cavity of each set of air passages 50 is provided with an inlet 500 and the other cavity is provided with an outlet 501.

[0051] Through the above-described embodiments of the purging assembly 5, the flow rate between the purging assembly 5 and the circulating airway 1 is ensured to be stable and uniform; in addition, in the above-described embodiments of the purging assembly 5, all airways 50 are connected to the circulating airway 1 in parallel.

[0052] The preceding text discussed that the permeation membrane 4 can be installed directly or indirectly within the interface 20, referring to... Figure 3 In one embodiment, the interface 20 also has a support component 6 for supporting the permeation membrane 4, which can be installed in the interface 20 through the support component 6.

[0053] The support component 6 includes a support ring 60 that is fitted to the inner wall contour of the interface 20. A support net 61 or several support rods can be installed inside the support ring 60 to support the permeation membrane 4.

[0054] For example, the support component 6 includes a support ring adapted to the contour of the inner wall of the interface 20 and a support mesh 61 arranged within the support ring. The permeable membrane 4 is supported on the mesh surface of the support mesh 61, and the mesh spacing of the support mesh 61 is 10 μm to 1000 μm.

[0055] Furthermore, in some embodiments, reference is made to Figure 3 The interface 20 is also equipped with a heat source 7 to improve the permeability of the permeation membrane 4. The heat source 7 is arranged on the side of the permeation membrane 4 near the protective layer 3. The function of the heat source 7 is to increase the permeation rate of gas molecules.

[0056] It is important to note that heat source 7 is not necessary for the gas detection device. If the permeation rate of the permeation membrane 4 in the gas detection device is sufficient to be detected under normal operating temperature conditions, then there is no need to set up heat source 7. Alternatively, heat source 7 can be set up in the gas detection device, which can be activated when needed and deactivated when not needed.

[0057] When the gas detection device is equipped with a heat source 7, the heat source 7 is installed between the protective layer 3 and the permeation membrane 4, but a certain distance must be left between the permeation membrane 4 and the heat source 7 to avoid the heat source 7 damaging the permeation membrane 4.

[0058] Reference Figure 3 When the gas detection device has both a heat source 7 and a support component 6, the heat source 7 and the permeation membrane 4 are separated by the support component 6.

[0059] Furthermore, when the gas detection device has both a support assembly 6 and a purging assembly 5, the permeation membrane 4 is pressed against the end faces of the housing 51 and the partition 52 by the support assembly 6.

[0060] In addition, as needed, the gas detection device has multiple gas sensors 11 connected in series on the circulating gas channel 1.

[0061] In addition, in order to reduce the dilution of the permeated gas concentration in the recirculating airway 1, the spacing between the multiple gas sensors 11 should be as small as possible; furthermore, the multiple gas sensors 11 can also be located as close as possible downstream of the interface 20 on the recirculating airway 1 to reduce the dilution of the gas concentration in the recirculating airway 1 before entering the gas sensor 11.

[0062] In the gas detection device of the present invention, the internal circulation airway 1 adopts a closed air path, and the multiple gas sensors 11 are set with a small spacing, so that the internal gas volume of the entire gas detection device is reduced to less than 1 cubic centimeter, thereby increasing the internal permeation molecule concentration of the gas detection device.

[0063] In addition, it should be noted that the aforementioned circulating air duct 1 can be the physical housing of the gas detection device, while the several gas sensors 11 connected in series on the circulating air duct 1 can be independently configured with protective housings; in this case, the interface 20 is opened on the circulating air duct 1.

[0064] Or, refer to Figure 1 In one embodiment, the gas detection device further includes a set of containers 2, with the interface 20 being an opening provided on the containers 2. The circulating air passage 1, the airflow generating device 10, and all the gas sensors 11 are all located inside the containers 2. In this case, the containers 2 form a detection bypass provided on the gas environment a to be detected.

[0065] Taking a cotton pneumatic conveying pipeline as an example of the gas environment to be detected (a), this paper illustrates a specific application scenario of the gas detection device of the present invention.

[0066] During the cotton ginning process, impurities entering the raw materials may cause the temperature of the cotton ginning machine to rise, leading to the ignition of the cotton passing through. Subsequently, the cotton is transported to the baling machine through airflow-driven pipes, carrying the ignition source into the compressed cotton bales, which may cause a fire during storage and transportation. During the cotton ginning process, the pneumatic conveying pipes for cotton are high-dust pipes. The gas detection device of this invention can be used for early detection of fire gases, thereby providing an early warning to stop the production line and eliminate the fire hazard. At this time, two gas sensors 11 are selected on the circulating air duct 1 of the gas detection device, namely a carbon monoxide electrochemical sensor and a photoionization sensor, which detect carbon monoxide and volatile organic compounds (VOCs), respectively. These two gases are the hallmark gases of very early fires.

[0067] in, Figure 7 The demonstration showed that the gas detection device successfully detected carbon monoxide and VOCs produced by smoldering cotton in a cotton conveying pipeline. As can be seen from the attached figure, the sensor's response time to the gas is on the order of seconds, indicating that the gas detection device can achieve rapid detection in high-dust environments. At the same time, the sensor in the gas detection device can still output a stable signal in high-dust, high-flow-rate pipelines, thus enabling timely and accurate early warning before the fire spreads.

[0068] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0069] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0070] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0071] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0072] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A gas detection device, characterized in that, include: A recirculating airway, which has or is connected to an interface for connecting to the gas environment to be detected; An airflow generating device, connected in series in the circulating air passage, is used to generate circulating airflow in the circulating air passage; At least one set of gas sensors is connected in series in the circulating airway; A protective layer that covers the interface and allows gas to pass through; and A permeation membrane is provided, which covers the interface and is disposed on the side of the protective layer away from the gas environment to be detected. The protective layer is used to press the permeation membrane, and the permeation membrane is used to permeate the gas filtered by the protective layer.

2. The gas detection device according to claim 1, characterized in that, The interface is also covered by a purging assembly, which is arranged on the side of the permeation membrane away from the protective layer. The purging assembly has multiple gas passages communicating with the permeation membrane, and all of the gas passages are connected to the circulating gas channel.

3. The gas detection device according to claim 2, characterized in that, In the purging assembly, one end of all the gas passages is covered by the permeation membrane and the other end is a closed end. The inlet and outlet for connecting the circulating gas passages are all located on the closed end of the gas passages.

4. The gas detection device according to claim 3, characterized in that, In the purging assembly, all the air passages are connected to the circulating air passage in parallel.

5. The gas detection device according to claim 1 or 3, characterized in that, The interface also includes a support component for supporting the permeation membrane.

6. The gas detection device according to claim 5, characterized in that, The support assembly includes a support ring adapted to the contour of the inner wall of the interface and a support mesh arranged within the support ring; the permeable membrane is supported on the mesh surface of the support mesh.

7. The gas detection device according to claim 1, characterized in that, The interface is also provided with a heat source for improving the permeability of the permeation membrane, and the heat source is arranged on the side of the permeation membrane close to the protective layer.

8. The gas detection device according to claim 1, characterized in that, The gas detection device has multiple gas sensors connected in series in the circulating gas channel.

9. The gas detection device according to claim 1, characterized in that, The airflow generating device is a rotary vane pump, diaphragm pump, piezoelectric pump, or fan.

10. The gas detection device according to claim 1, characterized in that, The gas detection device also includes a set of containers, and the interface is an opening provided on the containers; the circulating air passage, the airflow generating device and all the gas sensors are all located inside the containers.

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