A gas recognition system and method based on an array gas sensor

Abstract

The present invention relates to a gas recognition system and method based on an array gas sensor. The system includes a detection tube. The detection tube at least includes a gas sensor array. The gas sensor array consists of a shunt channel and a plurality of sensors, and the plurality of sensors are arranged in the shunt channel. The gas inlet of the detection tube is connected to at least two shunt channels through the tube body. In at least two shunt channels, filter membranes and sensors are provided based on several mixed components in the gas to achieve the differentiation and concentration detection of several mixed components. Through the design scheme of several shunt channels, filter membranes and sensors of the present invention, the reasons for the occurrence of the target gas can be distinguished. This rapid judgment method not only enables the gas pipeline network dispatching center to select different safety preplans according to the actual failure types, but also enables the detailed detection and determination of each component in the gas, so as to comprehensively record the gas changes in the entire urban gas pipeline network, prevent the large accumulation of combustible gases, and ensure safety.

Description

Technical Field

[0001] The present invention relates to the technical field of gas identification, and particularly to a gas identification system and method based on an array gas sensor. Background Art

[0002] Flammable gases include, but are not limited to, natural gas, coal gas, methane, acetylene, hydrogen, carbon monoxide, and the vapors of some flammable liquids such as ethanol, methanol, acetone, etc. When these gases reach a certain concentration in the air and encounter a spark, they will explode and burn. A large part of the urban gas pipeline network is set in places such as urban sewers, water supply wells, power cable trenches, and telecommunication pipeline wells. In these places, a large amount of debris often accumulates, and the debris ferments and precipitates in an oxygen-deficient environment for a long time to produce biogas with different concentrations, which brings great interference to gas leakage detection. Therefore, in the inspection work of the gas pipeline network, the main problems that trouble the staff are not only the portable, accurate and rapid detection of the methane concentration in natural gas, but also how to quickly determine whether the gas is biogas. The difference between natural gas and biogas is that natural gas contains ethane while biogas does not. When it is detected that the gas sample contains ethane, it can be determined that the gas is leaked from the gas pipeline. If the presence of ethane is not detected, it can be determined that it is underground biogas. The existing technology for identifying natural gas and biogas is mainly chromatographic separation. The defect of this technology is that it not only requires the equipped with hydrogen, but also the volume and convenience of the instrument are limited. To solve this deficiency, the present invention uses the combined differential response of several shunt channels, filter membranes and sensors to measure the concentrations of methane and ethane (or other gas components to be distinguished) in the target gas to distinguish biogas and natural gas, thus avoiding the use of consumable equipment such as hydrogen, making the instrument more convenient to carry and having a low maintenance cost.

[0003] Chinese Patent CN215415308U discloses a portable combustible gas detector, including a detector main body. A wire tube is arranged on the surface of the detector main body. The wire tube is a flexible metal wire tube. A detection probe is arranged on the upper surface of the wire tube. A threaded sleeve is connected to the outer surface of the detection probe by a thread. A square frame is fixedly connected to the inner surface of the threaded sleeve. One end of the square frame is fixedly connected to a motor. A fan blade is arranged on the outer surface of the driving shaft of the motor. An air inlet hole is arranged on the lower surface of the threaded sleeve. By providing an external air inlet component, the fan blade can be driven by the motor to rotate to conduct air outwards. The air flow quickly enters through the air inlet hole and can be sensed by the detection probe, which is convenient for improving the air intake detection amount, with sensitive detection, convenient use and convenient carrying.

[0004] Chinese Patent CN109752344B discloses a portable non-methane total hydrocarbon concentration detector and a non-methane total hydrocarbon concentration detection method. The portable non-methane total hydrocarbon concentration detector includes a housing and a sampling tube, a methane concentration detection device, a sampling pump, a total hydrocarbon concentration detection device, and a control system that are sequentially connected inside the housing. The control system can control the operations of the methane concentration detection device, the sampling pump, and the total hydrocarbon concentration detection device. Since the sample gas used in the front and back detection operations of the portable non-methane total hydrocarbon concentration detector of this patent does not need to be replaced and is the same sample gas, the detection result is not distorted, the detection accuracy is improved, at the same time, the time consumption caused by the switching of the two analyses is reduced, the detection efficiency is improved, and the volume and weight of the instrument are greatly reduced, and it can be miniaturized and is convenient to carry. However, neither of the above two patents can perform targeted, portable, and rapid detection of the remaining components in the gas to be detected, resulting in the inability of the staff to quickly and effectively conduct the inspection work on the gas pipeline network.

[0005] In addition, on the one hand, there are differences in the understanding of those skilled in the art; on the other hand, although the inventor studied a large number of documents and patents when making this invention, due to space limitations, all details and contents were not listed in detail. However, this does not mean that this invention does not possess the features of these prior arts. On the contrary, this invention already possesses all the features of the prior arts, and the applicant reserves the right to add relevant prior arts in the background art. Summary of the Invention

[0006] The prior art usually detects gas leakage in gas pipeline networks by detecting methane. However, since some parts of urban gas pipeline networks are in an oxygen-deficient environment, biogas with different concentrations may be generated, and biogas also contains a large amount of methane, resulting in the inability of the staff to distinguish the cause of the failure in the gas pipeline network. However, the difference between natural gas and biogas is that natural gas also contains ethane. For example, if a large amount of gas containing methane but not ethane appears in the underground gas pipeline network, it indicates that biogas has been generated under the long-term sedimentation in the underground gas pipeline network, rather than a gas leakage in the gas pipeline network. On this basis, the present invention sets several shunt channels so that the detection tube can judge various components and concentrations in the gas to be detected, thereby making a quick judgment on it and giving corresponding solutions.

[0007] Aiming at the deficiencies of the prior art, the technical solution of the present invention is to provide a gas recognition system based on an array gas sensor, including a detection tube. The detection tube at least includes a gas sensor array, and the gas sensor array is composed of a shunt channel and a plurality of sensors, and the plurality of sensors are arranged in the shunt channel. The gas inlet of the detection tube is connected to at least two of the shunt channels through a tube body, so that the gas entering from the gas inlet is split into at least two fluid streams. In at least two of the shunt channels, filter membranes and sensors are provided based on several mixed components in the gas to achieve the distinction and concentration detection of several mixed components. Through the above method, the reason for the appearance of the target gas can be distinguished, that is, the target gas appears due to a certain fault in the gas pipeline network. For example, a large amount of gas containing methane but not ethane appears in the underground gas pipeline network, indicating that biogas is generated under the long-term precipitation in the underground gas pipeline network, rather than a leakage in the gas pipeline network. This rapid judgment method not only enables the gas pipeline network dispatching center to select different safety plans according to the actual fault type, but also enables the detailed detection and determination of each component in the gas, so as to comprehensively record the gas changes in the entire urban gas pipeline network, prevent the large accumulation of combustible gases, and ensure safety. The present invention measures each gas component in the target gas through the combined differential response of several shunt channels, filter membranes and sensors. It is not only used for the daily inspection work of the gas pipeline network, but also can be effectively detected in dangerous environments such as sewage treatment plants, septic tanks, chemical enterprises, gas stations, and dangerous chemical warehouses, so as to prevent accidents and provide a technical basis for accident handling.

[0008] According to a preferred embodiment, the shunt channel has a streamlined structure to enable the gas to flow smoothly along the streamlined structure, and to make the gas flow direction fixed to enter the gas sensor array from the gas inlet, thereby increasing the intake detection amount.

[0009] According to a preferred embodiment, after at least two of the shunt channels split the gas at the gas inlet of the detection tube, and after passing through the filter membrane and the sensor, they are connected into a single channel, so that at least two fluid streams converge, thereby discharging the detected gas from the detection tube centrally. The converging process of at least two fluid streams can block the reverse flow of the gas along the detection tube. With such a setting, the gas to be measured is independently divided into two parts, and the components are detected separately, so as to obtain the component types and concentrations in the gas to be measured.

[0010] According to a preferred embodiment, the flow splitter includes a flow splitting end and a flow converging end. The flow splitting end is the end that contacts the gas and splits the gas; the flow converging end is the end where the gas leaves the flow splitter for flow convergence. Wherein, the radius of curvature of the flow converging end is greater than that of the flow splitting end. In addition to providing a space for splitting the gas and then detecting it separately, the flow splitter is also used to divide the gas flow path into multiple pressure zones, and generate resistance through the change of pressure difference to make the target gas flow out from the air outlet, preventing the remaining gas from flowing into the air outlet and interfering with the detection of the target gas, thus ensuring the accuracy of its detection. The radius of curvature of the flow converging end being greater than that of the flow splitting end reduces the kinetic energy of the gas overflowing from the air outlet. The gas is separated by multiple pressure zones in the flow splitter, so that under the action of the pressure gradient, the gas flow process is hindered. The setting of the flow splitter is beneficial to the unidirectional flow performance of the target gas. The set flow splitter blocks the reverse flow of the gas and acts as a one-way valve for gas flow. For example, when there is a tendency of reverse gas flow, due to the radius of curvature of the flow converging end being greater than that of the flow splitting end, the reverse gas is squeezed and hindered at the flow converging end, and even forms a vortex, so that the reverse gas cannot flow, preventing the reverse gas from flowing to the sensor and causing a decrease in the accuracy of concentration detection or even misjudgment.

[0011] According to a preferred embodiment, before the gas enters the flow splitter, the detection tube is at least provided with a basic sensor for detecting the initial gas to obtain the basic response of the gas. After the first sensor, there is an air pump for pumping in the initial gas, and the air pump also pushes the initial gas into the flow splitter. The air pump can suck the gas to be measured into the detection tube under the pumping action, and can accelerate the gas flow rate in the detection tube, thereby forming a pressure difference to force the gas to better enter several flow splitters.

[0012] According to a preferred embodiment, at least two of the flow splitters are provided with a first filter membrane, a second filter membrane, a first sensor and a second sensor. Among them, the first filter membrane and the first sensor are set as a group in one flow splitter; the second filter membrane and the second sensor are set as a group in another flow splitter. When the initial gas enters at least two of the flow splitters, the initial gas is split into two fluid streams to respectively pass through the first filter membrane and the second filter membrane, and flow to the first sensor and the second sensor respectively.

[0013] According to a preferred embodiment, the first filter membrane and / or the second filter membrane is based on the principle of like dissolves like to filter the interfering gas present in the gas, so that the gas to be measured in the gas passes through the first filter membrane and / or the second filter membrane to the first sensor and / or the second sensor. The interfering gas is at least composed of ethanol and / or water, and the gas to be measured at least includes methane or ethane.

[0014] According to a preferred embodiment, the first sensor and the second sensor respectively obtain a first response and a second response based on the gas to be measured, and the first response and the second response are compared with the base response through differential response comparison to calculate the types and concentrations of various components in the gas.

[0015] According to a preferred embodiment, the detection tube is provided with an air outlet for discharging gas, and the air outlet is arranged at the end of the gas sensor array along the gas flow direction.

[0016] The present invention also relates to a gas identification method based on an array gas sensor. When the detection tube at least includes a gas sensor array, and the gas sensor array is composed of a shunt channel and several sensors, and several of the sensors are arranged in the shunt channel, the method at least includes: the gas inlet of the detection tube is connected to at least two of the shunt channels through the tube body, so that the gas entering from the gas inlet is split into at least two fluid streams. Filters and sensors are provided in at least two of the shunt channels based on several mixed components in the gas to achieve the differentiation and concentration detection of several mixed components.

[0017] The beneficial technical effects of the present invention:

[0018] (1) Through the design scheme of several shunt channels, filters and sensors of the present invention, the reason for the appearance of the target gas can be distinguished, that is, the target gas appears due to a certain fault in the gas pipeline network. For example, when a large amount of gas containing methane but not ethane appears in the underground gas pipeline network, it indicates that biogas is generated under the long-term precipitation in the underground gas pipeline network, rather than a leakage in the gas pipeline network. This rapid judgment method not only enables the gas pipeline network dispatching center to select different safety preplans according to the actual type of fault, but also enables the detailed detection and determination of various components in the gas, so as to comprehensively record the gas changes in the entire urban gas pipeline network, prevent the large accumulation of combustible gas, and ensure safety. Through the combined differential response of several shunt channels, filters and sensors of the present invention, the gas components in the target gas are measured, which is not only used for the regular inspection work of the gas pipeline network, but also can be effectively detected in dangerous environments such as sewage treatment plants, septic tanks, chemical enterprises, gas stations, and dangerous chemical warehouses, so as to prevent accidents and provide a technical basis for accident handling;

[0019] (2)In addition to providing a space for shunting the gas for separate detection, the shunt channel is also used to divide the gas flow path into multiple pressure zones. By the change of the pressure difference, resistance is generated to make the target gas flow out from the air outlet, preventing the remaining gas from flowing into the air outlet and interfering with the detection of the target gas, thus ensuring the accuracy of its detection. The radius of curvature of the confluence end is greater than that of the shunt end, so that the gas overflowing into the air outlet has its kinetic energy reduced. The gas is separated by multiple pressure zones in the shunt channel, and under the action of the pressure gradient, its flow process is hindered. The setting of the shunt channel is beneficial to the unidirectional flow performance of the target gas. The set shunt channel blocks the reverse flow of the gas and acts as a one-way valve for gas flow. For example, when there is a tendency of reverse gas flow, due to the radius of curvature of the confluence end being greater than that of the shunt end, the reverse gas is squeezed and hindered at the confluence end, and even forms a vortex, so that the reverse gas cannot flow, preventing the reverse gas from flowing to the sensor and causing a decrease in the accuracy of concentration detection or even misjudgment. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of a preferred embodiment of the detection tube of the present invention;

[0021] Figure 2 is a module flow chart of a preferred embodiment of a gas recognition system based on an array gas sensor of the present invention;

[0022] Figure 3 is a schematic structural diagram of a preferred embodiment of the gas sensor array of the present invention;

[0023] Figure 4 is a schematic structural diagram of another preferred embodiment of the gas sensor array of the present invention.

[0024] List of Reference Numerals

[0025] 1: Detection tube; 2: Gas sensor array; 3: Shunt channel; 4: Signal processing circuit; 5: Main control unit; 6: Communication interface circuit; 101: Basic sensor; 102: Air pump; 103: First sensor; 104: Second sensor; 105: First filter membrane; 106: Second filter membrane; 107: Air outlet; 108: Third sensor; 109: Fourth sensor; 110: Branch channel. Detailed Description of the Embodiment

[0026] The following is a detailed description with reference to the drawings. Embodiment 1

[0027] This application relates to a gas identification system based on an array gas sensor, including a detection tube 1. The detection tube 1 at least includes a gas sensor array 2, and the gas sensor array 2 is composed of a flow splitter 3 and several sensors, and the several sensors are arranged in the flow splitter 3. The gas inlet of the detection tube 1 is connected to at least two flow splitters 3 through the tube body, so that the gas entering from the gas inlet is split into at least two fluid streams. In at least two flow splitters 3, filters and sensors are provided based on several mixed components in the gas to achieve the differentiation and concentration detection of several mixed components. The setting of multiple flow splitters 3 divides the interior of the detection tube 1 into multiple detection spaces, and performs a parallel detection on the target gas to detect different types of components (such as methane and ethane) contained in the target gas. Through the above method, the reason for the appearance of the target gas can be distinguished, that is, the target gas appears due to a certain fault in the gas pipeline network. For example, in the underground gas pipeline network, a large amount of gas containing methane but not ethane appears, indicating that under the long-term precipitation effect in the underground gas pipeline network, biogas is generated rather than the gas pipeline network leaks. This rapid judgment method not only enables the gas pipeline network dispatching center to select different safety plans according to the actual type of fault, but also enables a detailed detection and determination of each component in the gas, so as to overall record the gas changes in the entire urban gas pipeline network, prevent the large accumulation of combustible gas, and ensure safety. The present invention measures each gas component in the target gas through the combined differential response of several flow splitters 3, filters and sensors. It is not only used for the usual inspection work of the gas pipeline network, but also can be effectively detected in dangerous environments such as sewage treatment plants, septic tanks, chemical enterprises, gas stations, and dangerous chemical warehouses, so as to prevent accidents and provide a technical basis for accident handling.

[0028] According to a preferred embodiment, the flow splitter 3 has a streamlined structure to enable the gas to flow smoothly along the streamlined structure, and to make the gas flow direction fixed from the gas inlet into the gas sensor array 2, thereby increasing the intake detection amount.

[0029] According to a preferred embodiment, after at least two flow splitters 3 split the gas at the gas inlet of the detection tube 1, and after passing through the filter and the sensor, they are connected into a single channel, so that at least two fluid streams converge, thereby discharging the detected gas from the detection tube 1 in a concentrated manner. The converging process of at least two fluid streams can block the reverse flow of the gas along the detection tube 1. With such a setting, the gas to be measured is independently divided into two parts, and the components are respectively detected, so as to obtain the types and concentrations of the components in the gas to be measured.

[0030] According to a preferred embodiment, the flow divider 3 includes a flow dividing end and a flow converging end. The flow dividing end is the end that contacts the gas and divides the gas; the flow converging end is the end where the gas leaves the flow divider 3 for confluence. Among them, the radius of curvature of the flow converging end is greater than that of the flow dividing end. In addition to providing a space for dividing the gas and then separately detecting it, the flow divider 3 is also used to divide the gas flow path into multiple pressure zones, generating resistance through the change of pressure difference to make the target gas flow out from the air outlet 107, preventing the remaining gas from flowing into the air outlet 107 and interfering with the detection of the target gas, thus ensuring the accuracy of its detection. The fact that the radius of curvature of the flow converging end is greater than that of the flow dividing end reduces the power of the gas that overflows into the air outlet 107. The gas is separated by multiple pressure zones in the flow divider 3, so that under the action of the pressure gradient, the gas flow process is hindered. The setting of the flow divider 3 is beneficial to the unidirectional flow performance of the target gas. The radius of curvature of the flow dividing end is between 0.2 and 0.5 cm. The radius of curvature of the flow converging end is between 0.5 and 1 cm. Too large or too small a radius of curvature will cause different pressure drops at the inlet and outlet when the air flow enters it, which will instead cause the air flow to not flow stably. The provided flow divider 3 blocks the reverse flow of the gas and acts as a one-way valve for the gas flow. For example, when there is a tendency for the gas to flow reversely, due to the fact that the radius of curvature of the flow converging end is greater than that of the flow dividing end, the reverse gas is squeezed and hindered at the flow converging end, and even forms a vortex, so that the reverse gas cannot flow, preventing the reverse gas from flowing to the sensor and causing a decrease in the accuracy of the concentration detection or even a misjudgment.

[0031] According to a preferred embodiment, before the gas enters the flow divider 3, the detection tube 1 is provided with at least a basic sensor 101 for detecting the initial gas to obtain the basic response of the gas. After the basic sensor 101, there is an air pump 102 for pumping in the initial gas, and the air pump 102 also pushes the initial gas into the flow divider 3. The air pump 102 can suck the gas to be measured into the detection tube 1 under the pumping action and can accelerate the gas flow rate in the detection tube 1, thereby forming a pressure difference to force the gas to better enter several flow dividers 3.

[0032] According to a preferred embodiment, a first filter membrane 105, a second filter membrane 106, a first sensor 103, and a second sensor 104 are provided in at least two flow channels 3. Among them, the first filter membrane 105 and the first sensor 103 are set as a group in one flow channel; the second filter membrane 106 and the second sensor 104 are set as a group in another flow channel. When the initial gas enters at least two flow channels 3, the initial gas is split into two streams of fluid to pass through the first filter membrane 105 and the second filter membrane 106 respectively, and flow to the first sensor 103 and the second sensor 104 respectively. The first sensor 103 and the second sensor 104 can be set as a methane sensor array, such as a metal oxide-based one. This application also has a component for removing the influence of interfering gases such as humidity and ethanol. The detection tube 1 is internally provided with a basic sensor 101, a first sensor 103, and a second sensor 104. Among them, the basic sensor 101 is a relatively distal sensor, and the first sensor 103 and the second sensor 104 are relatively proximal sensors. The first filter membrane 105 and the second filter membrane 106 are dehumidifying membranes or VOC filter membranes. The differential response between the first sensor 103 and the second sensor 104 and the basic sensor 101 is used to judge the type and concentration of the gas. The air pump 102 can use a pump suction component to accelerate the gas flow rate. The first filter membrane 105 and the second filter membrane 106 are porous polar filter cottons (dehumidifying membranes or VOC filter membranes). According to the principle of "like dissolves like", that is, polar molecules are easily soluble in polar solvents, and non-polar molecules are easily soluble in non-polar solvents. The first filter membrane 105 and the second filter membrane 106 can use polar filter membranes, including PTFE membranes, etc., to filter interfering gases such as ethanol and humidity, so as to ensure that the passage of the target gas is not affected. It should be noted that for the functions required in the specific embodiments of the present invention, the first filter membrane 105 and the second filter membrane 106 based on the principle of like dissolves like are proposed, but this does not mean that the present invention does not include other principles required to achieve the same effect. Under the inspiration of the corresponding functions of the present invention, various other principle solutions are conceived, and these solutions also belong to the disclosure scope of the present invention and fall within the protection scope of the present invention.

[0033] According to a preferred embodiment, the first filter membrane 105 and / or the second filter membrane 106 are based on the principle of like dissolves like to filter interfering gases present in the gas, so that the gas to be detected in the gas passes through the first filter membrane 105 and / or the second filter membrane 106 to the first sensor 103 and / or the second sensor 104. The interfering gases consist of at least ethanol and / or water, and the gas to be detected includes at least methane or ethane.

[0034] According to a preferred embodiment, the first sensor 103 and the second sensor 104 respectively obtain a first response and a second response based on the gas to be detected, and the first response and the second response are compared with the basic response by differential response to calculate the type and concentration of each component in the gas.

[0035] According to a preferred embodiment, the detection tube 1 is provided with an air outlet 107 for discharging gas, and the air outlet 107 is arranged at the end of the gas sensor array 2 along the gas flow direction.

[0036] According to a preferred embodiment, a branch channel 110 for changing the pressure borne by the confluence end of the shunt channel can be arranged in the part of the shunt channel after the first sensor 103 and the second sensor 104. The gas after being detected by the first sensor 103 and the second sensor 104 needs to be discharged from the air outlet 107 to prevent accumulation in the shunt channel and affect the next detection. The curvature radius of the confluence end of the present invention is set to discharge the gas in the shunt channel as soon as possible. The discharge method is to form a pressure difference to accelerate the gas flow rate, so that the gas is discharged from the air outlet 107. However, the defect of this method is that: the too fast gas flow rate will cause an increase in the pressure difference, so that the first sensor 103 and the second sensor 104 are squeezed in the shunt channel 3, and even cause the shunt channel to deform and break. In view of this, the present invention arranges the branch channel 110 at the confluence end. As Figure 3 shown, multiple branch channels can be arc-shaped, Y-shaped, trapezoidal, etc., or set to other shapes according to needs. The diameter of the branch channel 110 is one-third to one-ninth of the shunt. The branch channel 110 is used to further change the pressure difference in the shunt channel 3, so that the gas can flow out of the air outlet 107 faster, and the gas pressure in the shunt channel 3 is reduced, preventing the shunt channel 3 from deforming, breaking, etc., and increasing the service life of the shunt channel 3.

[0037] According to a preferred embodiment, the first sensor 103 and the second sensor 104 can be arranged at the connection point between the shunt end and the confluence end. Since the curvature radius of the shunt end is small, when the gas reaches this connection point, the gas flow rate reaches the lowest point. Setting the sensor at the lowest gas flow rate is beneficial to improving the accuracy of gas component detection. Preferably, the third sensor 108 and the fourth sensor 109 can also be arranged at the shunt end inlet of the shunt channel. As Figure 4As shown, the flow rate of the gas at the inlet of the diverging end of the runner is not weakened by the pressure difference, that is, it is not hindered by the radius of curvature of the diverging end. The gas still maintains the maximum flow rate. The third sensor 108 and the fourth sensor 109 provided here can be used as the control group of the first sensor 103 and the second sensor 104. By detecting the component concentration of the gas at different flow rates, control group data can be obtained. This data can be used to determine whether the first sensor 103 and the second sensor 104 have detection failures, that is, the gas data detected by the first sensor 103 and the second sensor 104 and the gas data detected by the third sensor 108 and the fourth sensor 109 should be consistent or within the allowable error range. Otherwise, the sensor has a detection failure and needs to be repaired or replaced. Preferably, when the gas data detected by the first sensor 103 and the second sensor 104 is inconsistent with the gas data detected by the third sensor 108 and the fourth sensor 109, the gas flow rate can be increased to perform a secondary detection of the gas at different flow rates and determine whether there is a detection failure caused by too low gas flow rate or blockage. The increase in the gas flow rate can be achieved by increasing the power of the air pump 102. After the initial gas flow rate increases, the flow rate entering the runner 3 increases, so that the gas data measured by the first sensor 103, the second sensor 104, the third sensor 108, and the fourth sensor 109 are all under the condition of further increasing the gas flow rate.

[0038] According to a preferred embodiment, the setting of multiple sensors is also used to calibrate the measured gas component and concentration data. For example, when only a part of methane leaks in the gas pipeline network, it is possible that only a single sensor or not all sensors detect methane in the gas, while the remaining sensors do not detect methane in the gas. In this regard, the main control unit 5 re-collects and detects the gas through multiple sensors to calibrate the methane concentration or early warning detected at the previous moment, preventing misdetection. If the sensor also detects methane, it is determined that the methane concentration or early warning at the previous moment is the initial moment. If the sensor does not detect methane, it is determined that the methane concentration or early warning at the previous moment is a misdetection. During the second detection process, after the sensor detects methane, the main control unit 5 records the detection time points and measured concentrations of each sensor in the form of a time axis. The methane time point detected at the previous moment is set as the initial moment, and the methane concentration detected at the previous moment is the initial concentration, so that the main control unit 5 not only issues an early warning for methane leakage, but also issues corresponding early warnings in combination with the time axis for the change in methane concentration and the change in methane leakage time, and provides them to the gas pipeline network dispatching center so that the gas pipeline network dispatching center can make targeted deployments and propose corresponding solutions.

[0039] According to a preferred embodiment, the master control unit 5 can control the detection frequency of each sensor according to the gas flow rate in the runner 3. For example, the first sensor 103 and the second sensor 104 are synchronously detected as the same group of sensors, while the third sensor 108 and the fourth sensor 109 are synchronously detected as the same group of sensors, and the detection time points of the above two groups of sensors are different. That is, the above two groups of sensors use the cross-detection method to perform a covering detection on the gas to be measured. The purpose of this setting is that the covering detection at multiple time points can reduce the invalid data measured by multiple sensors, and the cross-detection method can cover the time axis so that the master control unit 5 can monitor the real-time data of the gas pipeline network and transmit it to the gas pipeline network dispatching center. The covering detection method makes the detection data of the gas pipeline network perfect, and at the same time reduces the detection times of a single sensor, thereby extending the service life of the sensor. The prior art often uses a single resistive sensor measurement method to detect the methane concentration. However, in the inspection work, the sensor needs to be frequently used to undertake a large amount of detection work. The multi-frequency use leads to the high-duration and low-efficiency operation of the sensor, resulting in a short service life. The covering cross-detection method adopted by the present invention can effectively solve the problem of the short service life of the sensor, and this method reduces the acquisition of invalid data, can also cover the detection time axis, and improves the detection accuracy and detection efficiency while having a low cost. Preferably, the first sensor 103 and the fourth sensor 109 can also be synchronously detected as the same group of sensors, while the second sensor 104 and the third sensor 108 are synchronously detected as the same group of sensors. The above improvements can be adaptively adjusted according to needs, and will not be elaborated here. The present invention also relates to a gas recognition method based on an array gas sensor. When the detection tube 1 at least includes a gas sensor array 2, and the gas sensor array 2 is composed of a runner 3 and several sensors, and several sensors are arranged in the runner 3, the method at least includes: the gas inlet of the detection tube 1 is connected to at least two runners 3 through the tube body, so that the gas entering from the gas inlet is split into at least two fluid streams. In at least two runners 3, filters and sensors are provided based on several mixed components in the gas to realize the distinction and concentration detection of several mixed components. Embodiment 2

[0040] This embodiment is a further and / or supplementary to the above embodiment, and the repeated content will not be elaborated.

[0041] According to a preferred embodiment, the differential response is compared at least by the processing module. Among them, the gas sensor array 2 sends the measured gas component concentration to the signal processing circuit of the processing module through A / D sampling, and the signal processing circuit is connected to the main control unit. The main control unit determines the type of gas and whether the methane and / or ethane gas concentration in the gas exceeds the safety threshold by comparing the baseline response with the difference between the first response and the second response. Since a filter membrane is provided between the sensors, the differential response characteristics of the sensors can reflect the gas type.

[0042] According to a preferred embodiment, the differential response judgment process for methane is as follows: When there is data interference, the responses of the basic sensor 101 and the first sensor 103 are th, which is the response value of the sensor and reflects the magnitude of the detection signal of the sensor. When the basic response is greater than th and the first response is less than th, the gas contains polar molecules blocked by the first filter membrane 105 and does not contain methane gas; when the basic response is greater than th, the first response is greater than th, and the basic response is greater than 0.8 times the first response and less than 1.2 - 5 times the first response, the methane gas concentration is judged according to the concentration conversion algorithm, and it is judged whether it exceeds the safety threshold; when the basic response is greater than th, the first response is greater than th, and the basic response is greater than 1.2 - 5 times the first response, then the gas contains non-polar interfering gases. Assume that data interference will cause the response to be th. When the basic response > th and the first response < th, the target gas is high-humidity water molecules or other polar molecules blocked by the filter membrane, and the processing unit 202 does not perform the concentration conversion algorithm to judge the methane gas concentration; the basic response > th, the first response > th, and (1.2 - 5) × the first response > the basic response > 0.8 × the first response, then the target gas contains methane gas, the methane gas concentration is judged according to the concentration conversion algorithm, and it is judged whether it exceeds the safety threshold to determine whether to alarm; the basic response > th, the first response > th, and the basic response > (1.2 - 5) the first response, then the target gas still contains non-polar interfering gases, and then according to the ratio of the basic response / the first response, combined with the machine learning algorithm, the types and concentrations of various mixed gases are calculated. Similarly, the differential response process for ethane can be carried out by replacing different filter membranes and sensors, which will not be elaborated here. It can be understood that for the remaining gas components that need to be detected, the same can be done by replacing the filter membranes and sensors. In the present invention, the first filter membrane 105 and the first sensor 103 can be set as the first component detection structure for detecting the methane component in the gas, and the second filter membrane 106 and the second sensor can be set as the second component detection structure for detecting the ethane component in the gas. The gas is split at the splitting end so that the gases entering the first component detection structure and the second component detection mechanism are the same, without detection error. If the sensors are placed in the same gas flow channel at the same time, it will cause the measured components and concentrations to affect each other, and the interfering gases affecting the detection of methane are different from those affecting the detection of ethane, and different filter membranes (i.e., the first filter membrane 105 and the second filter membrane 106) need to be used to filter them respectively. If only one gas flow channel is set, it will cause both the detection of methane and ethane to be affected by interfering gases, resulting in a reduction in detection accuracy and even misdetection. For this reason, the present invention sets several splitting channels 3 and sets different component detection structures therein to perform separated detection on the components and concentrations of the gas to be detected. It should be noted that the above basic response refers to the sensor response threshold caused by the methane concentration that needs to alarm.The ranges 1.2 to 5 above show the ranges of responses required for specific embodiments of the present invention, and do not mean that the ranges of responses required for other implementations with the same effects are not included.

[0043] In the prior art, catalytic combustible gas detectors are usually used for the detection of combustible gases, mainly utilizing the thermal effect principle of catalytic combustion. The sensor in the catalytic combustible gas detector can measure the gas by using the resistance change of a refractory metal platinum wire after heating under certain temperature conditions. However, the defect of this prior art is that the combustion values of different gases are different, and the sensor measures the resistance change caused by combustion rather than the change in concentration. Therefore, different gases may have different readings even at the same concentration. It has no selectivity within the gas range, and the sensor is vulnerable to the influence of compounds in the gas, resulting in a reduced service life. This detector also has many disadvantages such as too high working temperature and inability to be used in an oxygen-deficient environment.

[0044] Different from the prior art which detects by the change in resistivity, the present invention adopts a combined differential response method of several shunt channels 3, a filter membrane and a sensor, and quantitatively determines by differentially comparing the response values of the gas in the sensor. The response value is proportional to the component concentration, so as to obtain the concentrations of various gas components in the target gas, and a filter membrane is provided to filter the interfering components in the gas. This detection method avoids the problem that the target gas contains other mixed gases, resulting in the concentration measured by the combustion value being interfered by the mixed gases, making the detector non-selective, and this detection method will not generate heat to cause the service life of the detector to decrease. Its portable form enables the device to be used in a variety of complex environments. For example, when inspecting the urban underground gas pipeline network, in a narrow environment, the oxygen content is low, resulting in the problem of inability to burn. This detection method can not only detect the methane leaked due to the loss of the gas pipeline network, but also can detect the remaining gas components at the same time by setting different filter membranes and sensors, such as detecting ethane, so as to distinguish various mixed components in the target gas.

[0045] In the prior art, the gas leakage of the gas pipeline network is usually detected by detecting methane. However, since part of the urban gas pipeline network is in an oxygen-deficient environment, biogas with different concentrations may be generated, and biogas also contains a large amount of methane, resulting in the inability of the staff to distinguish the cause of the failure in the gas pipeline network. However, the difference between natural gas and biogas is that natural gas also contains ethane components. For example, in the underground gas pipeline network, if a large amount of gas containing methane but not ethane appears, it indicates that biogas is generated under the long-term sedimentation in the underground gas pipeline network rather than the gas pipeline network leaking. On this basis, the present invention sets several shunt channels 3, so that the detection tube can judge various components and concentrations in the gas to be detected, thereby making a quick judgment on it and giving corresponding solutions.

[0046] According to a preferred embodiment, the processing module is also provided with a communication interface circuit for connecting with an intelligent device for data interaction. The interactive data includes sensor calibration, sensor fault self-checking and methane concentration data storage, etc., so as to perform real-time recording and intelligent alarm through the intelligent device.

[0047] According to a preferred embodiment, the detection tube 1 and the gas sensor array 2 of the present invention can be connected to a mobile phone through a mobile phone charging port for charging or data transmission, thereby realizing a convenient outdoor gas pipeline network inspection. The detection tube 1 and the gas sensor array 2 can be configured with a large-capacity battery (with a remaining power prompt). The present invention also includes an alarm instrument, which includes the following functions: data storage function, alarm function, battery undervoltage prompt, wireless communication mode and sampling probe. The alarm instrument can also use a mobile phone module to realize sensor calibration, sensor fault self-check and intelligent alarm functions. Communication mode of the alarm instrument: data transmission through a mobile phone (such as a type-C port) through a protocol; communication through a Bluetooth module, and data transmission in conjunction with a mobile phone program or a WeChat applet. The alarm instrument can be developed and set up through a mobile phone program, wherein the system of the mobile phone can be an Android and / or IOS system. The alarm instrument can establish a database through tools such as MongoDB, SQL and Oracle. The positioning function of the alarm instrument can be used for GPS positioning, realizing real-time inspection, real-time trajectory, trajectory playback, equipment power management, pipeline management, official website drawing, third-party supervision, equipment management, account management and attendance photography and clocking in. Example 3

[0048] This embodiment is a further development and / or supplement to the above embodiments, and repeated contents will not be repeated here.

[0049] According to a preferred embodiment, the detection tube 1 is a single tube and has a built-in methane sensor array, for example, a metal oxide-based sensor to remove the influence of interfering gases such as humidity and ethanol.

[0050] According to a preferred embodiment, the detection tube 1 is a single tube and has one far and two near basic sensors 101, a first sensor 103 and a second sensor 104 built in, which are separated in the middle by a first filter membrane 105 and a second filter membrane 106, such as a dehumidification membrane or a VOC filter membrane, respectively. The differential response of the three sensors is used to determine the type and concentration of the gas, and a pump-suction air pump 102 can be used at the tail end to accelerate the gas flow rate.

[0051] According to a preferred embodiment, the air pump 102 can be placed between the basic sensor 101 and the first sensor 103 and / or the second sensor 104 to increase the pumping effect on the external gas.

[0052] According to a preferred embodiment, the detection tube 1 is a single tube, with a methane sensor array built therein, and a chromatographic column is also provided inside. The methane sensor is located at the end of the chromatographic column. The chromatographic column can separate different gases according to the boiling points, polarities, and adsorption properties of the flowing components, or determine the types of gases based on the flow time of the gases.

[0053] According to a preferred embodiment, the detection tube 1 is a single tube and internally provided with a basic sensor 101, a first sensor 103, and a second sensor 104, with one far and two near sensors. And a chromatographic column is also provided inside. The basic sensor 101 is located at the head end of the chromatographic column, and the first sensor 103 and the second sensor 104 are located at the end of the chromatographic column. The first sensor 103 and the second sensor 104 further determine the gas type.

[0054] According to a preferred embodiment, the detection tube 1 is a three-section single tube, internally provided with a basic sensor 101, a first sensor 103, and a second sensor 104, with one far and two near sensors. The first section internally houses the basic sensor 101, the third section internally houses the first sensor 103 and the second sensor 104, and the second section is the first filter membrane 105 and the second filter membrane 106, and the second section is a consumable. Whether the second section needs to be replaced is judged according to the responses of the basic sensor 101, the first sensor 103, and the second sensor 104; the three-section detection tube is connected by threads. When a problem occurs in the second tube containing the filter membrane, turn the threads to replace it. Specifically, when the basic sensor 101 in the first section has a response while the first sensor 103 and / or the second sensor 104 has no response, the device gives an alarm signal and the second tube needs to be replaced; or it can be tested with alcohol gas, change the working mode of the device to the test mode, and when the test result shows that the basic sensor 101, the first sensor 103, and the second sensor 104 all have responses, it is tested that the second tube needs to be replaced.

[0055] Throughout the text, the features guided by "preferably" are only an optional manner and should not be understood as must be set. Therefore, the applicant reserves the right to waive or delete the relevant preferred features at any time.

[0056] It should be noted that the above specific embodiments are exemplary. Those skilled in the art can come up with various solutions inspired by the disclosure content of the present invention, and these solutions also belong to the disclosure scope of the present invention and fall within the protection scope of the present invention. Those skilled in the art should understand that the description and drawings of the present invention are illustrative and do not constitute a limitation to the claims. The protection scope of the present invention is defined by the claims and their equivalents.

Claims

1. A gas recognition system based on an array gas sensor, comprising a detection tube (1), characterized in that, The detection tube (1) at least includes a gas sensor array (2), and the gas sensor array (2) is composed of a shunt channel (3) and a plurality of sensors, and the plurality of sensors are arranged in the shunt channel (3). The gas inlet of the detection tube (1) is connected to at least two of the shunt channels (3) through the tube body, so that the gas entering from the gas inlet is split into at least two fluid streams. In at least two of the shunt channels (3), a filter membrane and sensors are provided based on several mixed components in the gas to achieve the differentiation and concentration detection of several mixed components. The shunt channel (3) includes a shunt end and a confluence end. The shunt end is the end that contacts the gas and splits the gas; the confluence end is the end where the gas leaves the shunt channel (3) for confluence. Among them, the radius of curvature of the confluence end is greater than the radius of curvature of the shunt end.

2. The gas recognition system based on an array gas sensor according to claim 1, characterized in that, The shunt channel (3) has a streamlined structure to enable the gas to flow smoothly along the streamlined structure, and makes the gas flow direction fixed to enter the gas sensor array (2) from the gas inlet, thereby increasing the intake detection amount.

3. The gas recognition system based on an array gas sensor according to claim 2, characterized in that, After at least two of the shunt channels (3) split the gas at the gas inlet of the detection tube (1) and pass through the filter membrane and sensors, the two shunt channels (3) are connected into a single channel, so that at least two fluid streams are confluent, thereby discharging the detected gas out of the detection tube (1) centrally. The confluence process of at least two fluid streams can block the reverse flow of the gas along the detection tube (1).

4. The gas recognition system based on an array gas sensor according to claim 3, characterized in that, Before the gas enters the shunt channel (3), the detection tube (1) is at least provided with a basic sensor (101) for detecting the initial gas to obtain the basic response of the gas. After the basic sensor (101), an air pump (102) for pumping in the initial gas is provided, and the air pump (102) also pushes the initial gas into the shunt channel (3).

5. The gas recognition system based on an array gas sensor according to claim 4, characterized in that In at least two of the shunt channels (3), a first filter membrane (105), a second filter membrane (106), a first sensor (103) and a second sensor (104) are provided. Among them, the first filter membrane (105) and the first sensor (103) constitute a first component detection structure and are arranged in one shunt channel (3); the second filter membrane (106) and the second sensor (104) constitute a second component detection structure and are arranged in another shunt channel (3). Among them, When the initial gas enters at least two of the shunt channels (3), the initial gas is split into two fluid streams to respectively pass through the first filter membrane (105) and the second filter membrane (106), and flow to the first sensor (103) and the second sensor (104) respectively.

6. The gas recognition system based on an array gas sensor according to claim 5, characterized in that, The first filter membrane (105) and / or the second filter membrane (106) filter the interfering gas present in the gas based on the principle of like dissolves like, so that the gas to be measured in the gas passes through the first filter membrane (105) and / or the second filter membrane (106) in at least two of the shunt channels (3) and reaches the first sensor (103) and / or the second sensor (104). The interfering gas consists of at least ethanol and / or water, and the gas to be measured includes at least methane or ethane.

7. The gas recognition system based on an array gas sensor according to claim 6, characterized in that, The first sensor (103) and the second sensor (104) respectively obtain a first response and a second response based on the gas to be measured. The first response and the second response are compared with the baseline response by differential response to calculate the types and concentrations of various components in the gas.

8. The gas recognition system based on an array gas sensor according to claim 7, characterized in that, The detection tube (1) is provided with an air outlet (107) for discharging gas, and the air outlet (107) is arranged at the end of the gas sensor array (2) along the gas flow direction.

9. A gas recognition method based on an array gas sensor, characterized in that, When the detection tube (1) includes at least a gas sensor array (2), and the gas sensor array (2) is composed of a flow splitter (3) and several sensors, and several of the sensors are arranged in the flow splitter (3), the method at least includes: The gas inlet of the detection tube (1) is connected to at least two of the flow splitters (3) through the tube body, so that the gas entering from the gas inlet is split into at least two fluid streams. In at least two of the flow splitters (3), filters and sensors are provided based on several mixed components in the gas to distinguish and detect the concentrations of several mixed components. The flow splitter (3) includes a splitting end and a confluence end. The splitting end is the end that contacts the gas and splits the gas; the confluence end is the end where the gas leaves the flow splitter (3) for confluence; wherein, the radius of curvature of the confluence end is greater than the radius of curvature of the splitting end.

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